Cellulose nitrates and polyvinyl alcohol nitrates

The present invention relates to a process for the preparation of a cellulose sulfate ester, respectively of a polysaccharide partially substituted with ether or ester groups. ⁵

Methods for obtaining esters of polyhydroxyl polymers are known. The physical and chemical properties of these ester derivatives depend largely on the particular nature of the polymer, its molecular weight, the type of the substituent ester group and the degree of substitution of the polymer. Due to the method of preparing esters of polyhydroxyl polymers, according to known procedures, the degree of substitution of the resulting esters is not relatively uniform. These processes lead to the production of ester derivatives whose properties, such as water solubility and compatibility with ²⁰different metal ions are generally not satisfactory and restrict the area of ​​use of the obtained esters.

The process for preparing a cellulose sulfate ester from activated cellulose 25 by converting it to nitrite and converting nitrogen to sulfate, according to the invention, removes the above disadvantages by the fact that cellulose activated with a water content of up to 12% by weight, distributed uniform throughout the cellulose mass, it is treated with a strong polar aprotic solvent, to reduce the water content below 4% by weight, it is then contacted with nitrous tetraoxide or nitrosyl chloride at about 50 ° C, in the presence of a proton acceptor and a swelling or solubilizing solvent present in an amount of about three parts by weight for one part. activated cellulose, and the resulting nitrogenous cellulose ester is reacted with sulfur trioxide or a complex thereof, at a temperature between 0 and 25 ° C, giving a mixed ester of nitrite and cellulose sulfate, which is further treated with an aprotic solvent, to remove residual nitrogen groups, then the cellulose sulfate ester is treated with a base to obtain the cellulose sulfate ester in the form of salt.

16 examples of embodiments of the invention are given below.

Example 1. In a three-neck, round-bottomed vial, equipped with a mechanical stirrer and a calcium chloride tube, 20 g of cellulose powder are introduced, us76171

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pre-overnight, at a temperature of 11O ° C. 200 ml of Ν, oz-dimstyl are added to the cellulose powder^:ormamide and the mixture is stirred at room temperature. To this mixture is slowly added, in the absence of moisture, nitrogen tetraoxide (N₂A₄), within 2 hours.

A thickening of the mixture is observed when about 7 ... 8 g of N is added₂A₄and the appearance of a viscous, transparent mixture ¹⁰rent, without the appearance of any coloration, when adding about 15 g of N₂A₄.

After introduction of approximately 30 g of N₂A₄, the mixture forms a viscous blue-green solution and, upon addition 15 further of N₂A₄, the color turns to dark green, while the viscosity seems to remain constant.

It is added to a sample of the three ₂o solutions an excess of pyridine and the weak alkaline mixture is stirred with ice over water. A fibrous precipitate is formed which is removed, washed with ice water and squeezed, temperature₂5 being kept at this time at 0 ...

5 ° C. The fibrous precipitate in the first two samples is inflatable, and that in the third sample is soluble in ordinary solvents of polymeric esters, such as: dimethylformamide, dimethylacetamide, benzene, acetone and ethyl acetate. When trying to dry the fibrous precipitate, it decomposes, as shown by the gray smoke emissions. The resulting dry product 35 is insoluble in ordinary solvents of the polymeric esters described above.

In order to identify the resulting product as being nitrogen by cellulose and to determine the degree of substitution or esterification, the product is decomposed and cellulose and azPtos acid are determined. The products isolated from the above three solutions are washed with ice water and suspended in distilled water, in a closed Erlenmeyer flask, acidified with sulfuric acid and stirred magnetically at room temperature for one hour. The mixture is then neutralized with sodium hydroxide and the insoluble cellulose is regenerated, separated by filtration, washed with distilled water and dried in vacuo at 1 ° C. The filtrate is collected for testing, as described below.

The identity of the regenerated cellulose was determined by comparing the regenerated cellulose with the raw material, by infrared spectrophotometry, by nitrogen analysis and found identical by the Kjieldahl method and by the absence of carboxyl groups.

In order to determine the lack of depolymerization of the molecule during the reaction and during the storage of the reaction medium, the viscosity of the regenerated cellulose from reaction mixtures is kept for different periods of time in Cupro-ammoniacal hydroxide solution, with the viscosity of the raw material in the same solution and at a concentration of 0.5%. The viscosity was measured with a viscometer at 25 ° C. The results of these tests are presented in the following table.

Table 1

<td>The material</td><td>Time of depositors, in hours</td><td>Storage temperature, in ° C</td><td>Viscosity, in seconds</td>

<td>Cellulose-raw material {control)</td><td></td><td></td><td> 28,8</td>

<td>Regenerated cellulose</td><td> 6</td><td> 5</td><td> 27,0</td>

<td>Regenerated cellulose</td><td> 30</td><td> 5</td><td> 28,8</td>

<td>Regenerated cellulose</td><td> 120</td><td> 5</td><td> 28,3</td>

<td>Regenerated cellulose</td><td> 238</td><td> 5</td><td> 27,8</td>

The sulfur in the filtrate is determined by oxidation with permanganate solution to nitric acid. The presence of nitric acid as a result of oxidation is determined by its determination as nitrate nitrogen. 40

The degree of substitution was calculated from the weight of cellulose and the amount of nitric acid. The degree of substitution calculated for the first solution, which contains 45

7 ... 8 g of N₂A₄, was 0.7, for the second solution, which contains about 15 g of N₂A₄, was 1.5 and for the third solution, which contains about 30 g of N₂A₄, was 2.8.

Similar results were obtained when, instead of cellulose powder, pulp of cotton liner, cellulose from

70 171 wood or insulated from shells of rice, maize, barley, oats and cane. However, when using the above materials, the amount of dimethylformamide used must be increased due to the high viscosity of the resulting products. Partially substituted celluloses, such as methyl or carboxymethylcellulose, may also be used, with substantially similar results, except that the amount of reagent required for complete nitrosation is smaller due to the smaller number of free hydroxyl groups present. . Also, results similar to the above were obtained and when N, N-dimethylformamide was replaced with the following solvents: · Ν, Ν-dimethifacetamide, pyridine, quinine and mixtures thereof, as well as mixtures of one or more of the above solvents, with benzene, ethyl acetate or acetone. It has also been observed that nitrogen tetraoxide in the form of gas may be replaced with liquid tetraoxide or liquid solution of nitrogen tetraoxide or with nifrozil chloride, in one of the above solvents to obtain similar results. essentially.

Example 2. For the preparation of hemicellulose nitrogen from hemicellulose, a 500 ml round-bottomed three-necked bottle is provided, equipped with mechanical stirrer and calcium chloride tube, with 40 g of hemicellulose extracted from corn husks and suspended. in 300 ml of dimethylformamide. The suspension is stirred mechanically and, under conditions of exclusion of moisture, slowly add 50 g of nitrogen gas tetraoxide at room temperature, obtaining a clear, viscous solution of hemicellulose nitrogen.

To a portion of this solution is added an excess of pyridine and the weak alkaline solution is slowly poured, with shaking, in ice water, to separate a fibrous precipitate. Remove the precipitate, wash egg-water with ice and squeeze. The resulting precipitate is soluble in the ordinary solvents of the polymer esters described in Example 1. Upon drying, the precipitate decomposes, yielding a brown smoke.

Hemicellulose was regenerated for analysis by the slow addition of a portion of the remaining hemicellulose nitrate solution to 4 volts of methanol, stirring egg, when a precipitate is obtained which is filtered, washed with methanol and dried. The precipitate was identified to be hemicellulose, by infrared spectrophotometry and by nitrogen analysis according to the Kjieldahl method.

The absence of depolymerization of regenerated hemicellulose was determined by pre-setting a 2% aqueous solution of regenerated product and raw material and adjusting the pH of the solutions to 6.7, an egg solution of dilute sodium hydroxide. Dream⁵ the cohesions of the two solutions were measured with a viscometer, at 25 ° C. The viscosity of the regenerated hemicellulose was 138.5 s and the raw material was 146.2 s.

^ίθ To identify the product as. being nitrogen and to determine the degree of substitution, an excess of triethyls is added · amine takes the reaction mixture and the weak alkaline solution is poured slowly and with stirring¹⁵ in ice water, resulting from the separation of nitrite from hemicellulose. Remove the hemicellulose nitrogen, suspend it in water, and the mixture is acidified with sulfuric acid and stirred for^2&lt;! about 1 h. The mixture is then neutralized with sodium hydroxide and the neutral solution is added to 4 volts of methanol, when the hemicellulose is separated, which is removed, washed with methanol, ²⁵ dry and, $ e weighs.

Collect the filtrate, remove the methanol by vacuum concentration and the resulting aqueous nitrogen solution is oxidized with a permanganate solution,^it tru to form nitric acid, the presence of which is determined by its determination as nitrate nitrogen, by the Hick method.

The degree of substitution is calculated from the weight of hemicellulose and the quantity ³⁵ of nitric acid, obtaining a value of about 2.0. When using a quantity smaller than N₂A₄, the degree of substitution was correspondingly lower.

Similar results are obtained ¹ above, when instead of N, N-dimethyl formamide was used N, N-dimefilacetamide, pyridine, quinine and mixtures thereof, as mixtures of one or more of the above solvents, ⁴⁵ with benzene, ethyl acetate or acetone. Also, in order to obtain similar results, liquid nitrogen tetraoxide or nitrosyl chloride may be used instead of nitrogen gas teiraoxide.

Hemicellulose nitrate is prepared from hemicellulose nitrogen.

Example 3. For the preparation of starch nitrite from pregelatinized starch, 40 g of pregelatinized starch is introduced, ⁵⁵ in a 500 ml round-bottomed bottle with three necks, equipped with a mechanical stirrer and a calcium chloride tube and suspended in 300 ml of N, N-dimethylformamide. In the conditions of lack of humidity, in⁶⁰ the reaction mass is gradually introduced about 64 g of nitrogen gas tetraoxide, at room temperature and the mixture is stirred mechanically, to obtain a viscous, clear, a65 nitrogen starch solution.

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To test the resultant solution, an excess of pyridine is added to a portion of the solution and the weak alkaline mixture is slowly poured, with shaking, into water with. ice, to separate a fibrous precipitate. The precipitate is removed, if. wash with ice water and squeeze egg. The resulting precipitate is soluble in the ordinary solvents of the polymeric esters described in Example 1, upon drying, the precipitate decomposes to give off brown vapors indicating the presence of nitrogen. The dry precipitate is tested again for solubility, noting that it is insoluble in ordinary solvents of polymer esters.

The other portion of the solution of starch nitrate solution is slowly added to 4 volts of methanol, with stirring, and the precipitate is identified as starch by infrared spectrophotometry and nitrogen analysis by the Kjieidah method].

The absence of depolymerization of the regenerated starch was · determined by preparing a 1% aqueous solution of regenerated product and comparing its viscosity or that of the raw material. The solutions were adjusted to pH = 6.0 with a dilute solution of sodium hydroxide and the viscosities of the two solutions were measured with a viscometer, at a temperature of 25 ° C. The viscosity of the regenerated starch was

29.3 s compared to 30.4 s for the raw material.

The product was identified as starch nitrogen, its degree of substitution being determined by the hemicode method, described in example 2. The degree of substitution calculated from the weight of starch and from the amount of nitric acid was about 2.8. The degree of substitution was lower, when smaller quantities of nitrogen tetraoxide were used for niirose.

Results similar to the above were obtained when, instead of the starch, the following raw materials were used. alginic acid, agar, polysaccharides in some species of acacia, as well as starch derivatives containing free hydroxyl groups, such as hydroxyethyl starch. Similar results are also obtained when, in place of N, N-dimethylformamide, N is used; N-dimethylacetamide, pyridine, quinoline and mixtures thereof, as well as mixtures of one or more of the above solvents, with benzene, ethyl acetate or acetone. Similar results are also obtained if, instead of nitrous nitrogen tetraoxide, nitrous chloride, liquid nitrogen tetraoxide or a solution of nitrogen tetraoxide is used in one of the above solvents.

EXAMPLE 4 For the preparation of azotituS of polyvinyl alcohol from polyvinyl alcohol, in a dry 500 ml flask, with three thrips and a round bottom, 10 g of finely ground polyvinyl alcohol having a degree of saponification greater than 90% is suspended, in 100 ml of NiN-dimethylformamide. The mixture is stirred mechanically and tetraoxide of nitrogen gas is introduced, the absence of moisture. The vessel is cooled to a cold temperature, keeping the temperature at about 25 ° C. When adding about 20 g of tetraoxide nitrogen gas, a clear, viscous solution is obtained.

In the analysis, after. the methods described in Examples 2 and 3, the resulting product sq. identified to be polyvinyl nitrate with a substitution degree of 0.8.

It was observed that crunches when polyvinyl atococl. used as raw material has a degree of saponification of less than. 90%, (for example, a product containing about 50% acetyl groups and 50% free hydroxyl groups), obtain essentially the same results as above, by means of which the amount of nitrogen tetraoxide gas required to solubilize the starting material is smaller.

Example 5t To prepare cellulose sulfuric ester, suspend 10 g of high quality polymer liner pulp, in 500 ml of N, N-dimethylformamide and se. treats with nitrogen t-etraoxide to obtain nitrogen with a maximum degree of substitution, according to example 1. To the mixture containing nitrogen is added 40 ml of Ν, Ν-dimethylformamide containing 3.5 g of sulfur trioxide dropwise over a period of about 40 minutes, maintaining the solution temperature at 15 ° C, with vigorous agitation, to close a solution, viscous. To the viscous solution, add 20 ml of water and then pour slowly, with vigorous agitation, into 3 volts of acetone, to precipitate the sulfuric ester of cellulose. The precipitate is kneaded, washed with acetone and dissolved again in ice water.

For the preparation of sodium cellulose sulfate, the solution prepared above is neutralized by the addition of sodium hydroxide at a pH of about 8.0 to form a viscous solution of sodium cellulose sulfate. The solution is added slowly and with stirring, your 3 vol. acetone, for precipitating and isolating the product. The precipitated product is kneaded, collected, washed with fresh acetone and dried. In the analysis, the yield of sodium cellulose sulphate was 13.9 g, the product having a substitution degree of 0.65 and a viscosity of 6500 cP, as aqueous solution ^1θ/ Ο ·

The viscosity was measured with a viscometer, at 12 rpm, at a temperature of 25 ° C. To determine the degree of substitution, dissolve 0.4 g aliquots in a 20% aqueous hydrochloric acid solution and heat for 15 hours at 10 ° C. A dark brown solution is formed, which is filtered. To the filtrate is added an excess of acetate. barium, for precipitation of sulfuric acid as barium sulfate. The barium sulphate is dried and weighed, from the data, obtained by increasing the degree of substitution.

The results are obtained, essentially, similar to the above, when instead of the cotton liner pulp, as raw materials, were used: cellulose from other sources and / or with a polymer maadedus arad. , hemtceluTose arabic gum, starch, alginic acid, agar, polysaccharides ^ from acacia and alcohol, polyvinyl. Other solvents, capable of forming a complex with sulfur trioxide, and which may replace N, N-dimethylformamide in the complex N, N-dimethylformamide - sulfur trioxide, are N, N-dimethylacetamide, pyridine, tri alkylamines, dimethylsulfoxide and dioxane. Sulfur trioxide can also be added to the solution in liquid or gaseous form or diluted with an inert solvent, such as aryl in carbon tetrachloride, although the reaction is strongly exothermic, with the use of an ice bath.

Upon repetition, in the above process, with the amount of sulfur trioxide reduced to 2.5 g, the resulting product has a substitution degree of about Q, 5 and a viscosity of about 6000, cR. The yield is slightly reduced, being 13.4 g.

The size of the sulfur trioxide at about 4 ... 5 g and at about 6 ... 7 g results in a sulfation degree of about 0.7 ... 0.9 and about 1.0 ... 1.1 and at viscosities of about 6000 ... 8000 cR and about 3000 .., 4000 cP respectively. However, under these conditions, a greater increase in the amount of trioxide: sulfur does not lead to · values ​​of the degree of sulfation far above the value of 1,0, 1,1.

To. obtained - similar results, when cellulose nitrogen was used, with a sulphate degree of 2.4 ... 2.5.

Values ​​of 1.2 ... 1.3 and about

1.5, .. 1.6 of the degree of sulfation, when using a cellulose nitrogen, having a degree of sulfation of about 1.7 ... 2.0 and about 1.4 ... 1.6, by increasing the amount of sulfur trioxide takes about 8 ... 10 g and 12, -14 g respectively. The viscosities of the 1% aqueous solutions of the products were about 1500 ... 2000 cR and about 800 ... 1500 cP respectively. Similar results were obtained by using starch, ager and polysaccharides from acacia - as well as hemicelluloses. Also, for nitrosuration the sum of_: sulphates are suitable methyl cellulose with a. degree of sulphate of waxy as 1,0, 1,5, carboxymethyl cellulose, hydroxy-ilamidone, alginic and pectic acids acetylated (with an acetylation degree below about 1.5) and hydroxypropyl agar. However, the amount of reagent required for complete nitration depends only on the number of free hydroxyl groups.

When using cellulose from cotton liner, with a lower degree of polymerization, the degree of sulfation was similar, but the viscosities were correspondingly lower. Similarly, by using cellulose from other sources, products with lower viscosities were generally obtained.

Example! 6. Suspend 25 g of cellulose in 1000 ml of Ν, Ν-dimethylformamide and enter about 38 g of N 2 O 2 to obtain cellulose nitrogen. A solution of complex N, N-cHmethylformamide - sulfur trioxide in N, N-dimethylformamide, in calculated quantities is then added slowly, to give a degree of sulfation of about 0.8.

At this stage, a small portion of the mixture is removed and, after removal of the nitrogen and neutralization groups, the product is dialyzed, isolated and analyzed. The degree of sulfation was 0.8.

The main portion is mixed with the stoichiometric quantity of methanol, necessary for the quantitative removal of the nitrite groups, and then another portion of complex, Ν-dimethylformamide - sulfur trioxide, theoretically sufficient for growth, is added in a period of 2 h. of the sulphate degree at about 2.0. After a total reaction period of about 3 hours, the mixture is neutralized and the product is isolated, as described above, dialyzed and its degree of sulfation determined. The calculated sulfation degree was 0.8, indicating that no further substitution occurred after removal of the nitrogen groups.

Similar results were obtained when using acar and polysaccharides from acacia. This illustrates the fact that sulfation under these conditions does not take place without the prior nitration step.

Example 7. To test the compatibility of the various sodium cellulose sulphates with the metal ions, a 1% aqueous solution of the esters is mixed, with an equal volume of 20% salt solution, In cases where 20% means a higher than saturated concentration , a saturated salt solution is used.

Products with any degree of de-sulfation have proven to be compatible, not necessarily precipitation or gelling with ammonium sulfate, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, calcium hydroxide, strontium chloride, hydroxide strontium, aluminum sulphate, sodium alumina, zinc sulphate, sodium zinc, nickel sulphate, cobalt sulphate, copper sulphate, cadmium chloride, ferrous sulphate, chromic chloride, lead acetate, mercuric acetate, silver nitrate, tin chloride and sodium tin.

To perform a simple test to determine compatibility with metal ions, mix a 2% solution of cellulose sulfate in aqueous medium, with a 2% solution of potassium chloride, taken in equal volumes, after heating both solutions at a temperature of about 80 ° C. After mixing, the mixture is allowed to cool. The compatibility of cellulose sulphate with potassium ions is shown by the absence of the precipitate and the absence of gelling.

Sodium cellulose sulphate, with a sulphate grade of about 1.3 and smaller, is also compatible with barium acetate, barium hydroxide, waxy chloride and ferric chloride.

In most cases, the solutions can be saturated with salt, without this causing precipitation or gelling.

Example S. Preparation of a thickening alcoholic composition, of removal, consisting of 5.0% by weight cellulose nitrogen, 25.0% by weight water and 70.0% by weight ethyl alcohol. The composition has a high viscosity, which tends to slow the evaporation of the alcoholic solution, prolong the contact with the skin and thus increase the absorption.

Example 9, Prepare a slow-moving slurry, consisting of 150.0 g of glue, 5 g of cellulose sulfate ds sodium and 1000 g of water. This improvement glue has a high viscosity that tends to delay glue leakage, especially¹ from vertical surfaces. This special composition has a viscosity of 1,000 cP, at 25 ° C and about 300 cP, at SOȚ and does not interfere with or modify the properties of the solder glue.

Among other uses of cellulose sulphate, obtained by the process according to the invention, its application is mentioned in oil drilling muds, as a suspending agent, in the secondary recovery of crude oil by flotation with water, as a thickening agent of the aqueous phase, in cosmetics, as emulsifier and emollient, in foodstuffs, a thickening and stabilizing agent, in cleaning compositions, as a stabilizer and thickening agent, in wax emulsions, paints and in photo-emulsions, for example, for protein reactivation efc,

By using the process, as described above, esters of polyhydroxyl polymers can be prepared, such as: polysaccharides, polyvinyl alcohols, polysaccharides and partially substituted, etherified or esterified polyvinyl alcohols, which still contain a large number. free, thus obtaining the following specific products:

- Nitrates of polysaccharides, polyvinyl alcohols, polysaccharides partially substituted with stable radicals and polyvinyl alcohols, partially substituted, with stable radicals;

- nitrates of starch, starch, polysaccharides from acacia, hemicellulose, gum arabic, manganese, alginic and pectic acid, egg with a degree of sulfation between 0.1 and maximum _;

- cellulose nitrite, with a degree of sulfation between about 0.1 and about 2.0;

- cellulose nitrogen, with a degree of sulfation between about 2.0 and about 3.0;

- water-soluble nitrates of polysaccharide and polyvinyl alcohols, with a degree of sulfation of less than 1.0;

- sulfuric acid esters of polysaccharides and polyvinyl alcohols, as well as their salts, with a degree of sulfation of less than 2,0 and a substantially uniform distribution of sulfate groups in the molecule;

- sulfuric acid esters of acgarine and polysaccharides from acacia, with a degree of sulfation between 1.0 and 2.0;

- sulfuric acid esters of cellulose, with a degree of sulfation between 1.0 and 2.0;

- sulfuric acid esters of water-soluble cellulose, with a degree of sulfation between 0.3 and 1.0 _;

- cellulose sulfuric acid esters, with a degree of sulfation between 1.0 and 1.3, whose aqueous solutions are compatible and not negligible in the presence of potassium, barium, strontium, cerium, aluminum and ferric iron ions;

- sulfuric acid esters of cellulose, with a degree of sulfation of less than 2.0 and with a substantially uniform distribution of sulphate groups in moles, whose aqueous solutions are compatible and not detectable in the presence of potassium, strontium and aluminum ions.

Example 10, Dry at 100, 110 ° C, in vacuo, in the presence of P2O5, an amount of liner pulp. Cotton, for 5 hours, a dry portion of 20 g, of this quantity is introduced into a round-bottomed bottle, with 3 necks, provided with a calcium chloride tube, a strong stirrer and a dropper and is added 1 L of N, N-dimethylpharm76171 amide: Se: then enter an amount of '30 g- of N₂A₄ with - stirring, for a period of about 30: min, maintaining the temperature of the reaction mixture below 30 ° C, by cooling in a cold water bath, the mixture is thickened; but the reaction is not complete even after: mixing, time. for several hours, as indicated by the presence of turbulence and fibers, apparently reacted to us. By adding cr additional 3 g of N₂0₄ no substantial improvement is achieved.

To isolate and analyze the resulting cellulose nitrogen, a small portion of the mixture is added. excess pyridine. The weak alkaline mixture is poured over ice water, sc collects the precipitate, is washed with ice / water and squeezed, the temperature being maintained at 0 ° C. The material is dispersed in distilled water, in a closed Erict'.meyar vial and acidified with sulfuric acid. After stirring, magnetic, for about 1 h, the mixture is neutralized and the regenerated cellulose is removed, washed, dried: and weighed. Fâltralubse collects · quantitatively and is determined to azotruth, by oxidation with. permanganate to nitric acid. Presence: nitric acid after oxidation is determined by its determination as nitro nitrate, according to the Hi'ck method. The degree of non-delivery was about 2.7 ... 2.8.

The reaction mixture of nitrogen de-cellulose, prepared from 20 g of cellulose and 30 g _;from N₂A₄ is sulfated by the gradual addition (in about 30 min) of a solution of N complex; N-dimethylformamide - sulfur trioxide (about 6 g SGj) in

N, Nrdymethyl, formamide. The reaction is carried out with strong agitation and, in the absence of moisture, the temperature is kept below about 20 C. The mixture remains cloudy, and still contains fibers, even after a mixing of about 1 ... 2 h. The reaction mixture. is then transferred to an anisphere. diluted with about 500 ml of water and the plrl is adjusted to 7 ... 8, by gradual addition of sodium carbonate solution, during neutralization, the temperature of the mixture was kept below 2O ... 25 ° C, by addition, of. ice. It. add a sufficient quantity of isopropanol, to separate the product, the product is squeezed, washed, twice · egg an aqueous solution of isopropanol, dried again, dried in vacuo at 100 ° C and ground. The product has a sulfation degree of approx

O, 6 and the 1% aqueous solution has a viscosity · of about 3000'cP, but it has a long • appearance and contains fibers.

In another experiment, 20 g of anhydrous cotton detergent pulp is treated, as described above, but using only 15 g of N / O &lt;for nephrosion, to obtain a degree of sulfation of approx. 1.5 and an amount of complex N, N-dimethylformamide - sulfur trioxide, with a content of about 12 g of SO₃, for further sulfation. The results were similar to the ones above. The cellulose sulphate had a sulfation rate of about 1.5 and a 1% aqueous solution had a viscosity of about 500 cP, but it was cloudy and contained fibers.

Similar, essentially, results were obtained, then, instead of the cotton liner pulp, wood cellulose, cellulose from vegetable bark or from sugar cane and chemically treated and degraded cellulose, such as powdery mildew, were used. cellulose. However, it appears that the reaction with cellulose powder proceeds more smoothly and that the solution of the final sulphate product is less cloudy and contains a smaller amount of fiber than when using other types of cellulose.

By replacing N, N'-dimethylformamide with dimethylacetamide or pridine or mixtures of these compounds in the reaction medium, the results do not change substantially. Also, no essential difference was observed when sulfur trioxide was used in complex form with other solvents, such as dimethylacetamide, dioxane, dimethylsulfoxide and others or peanuts when, instead of N₂A₄, NOCI was used provided the molar quantity of NOCI was increased by 2.5 up to 3 times.

Example 11. The cotton liner pulp, described in the previous example, is suspended in water and mixed in a mixer, for 2 minutes, squeezed, washed with Ν, Ν-dirnetylfonnamide and squeezed again in this currently, cellulose has a water content of about 8 ... 10%. A 20 g portion of this cellulose: it is then nitrided with 30 g of N₂A₄, as described above. The resulting solution is clear and contains no fibers after a reaction time of 20 ... 30 min, with no excess N required.₂A₄to get a quantitative reaction. The sulfation was carried out as described above, obtaining a product which forms perfectly clear solutions, which do not contain fibers.

Similar results were obtained when the residual water content was 5% and 2% or when, instead of cotton cellulose, wood cellulose or sugar cane or chemically treated cellulose was used.

When the quantity of complex

Ν, Ν-dimethylformamide - sulfur trioxide added 'was equal to the amount calculated' to produce a strong sulfur16 degree of less than about 0.3 ... 0.4, the resulting product was insoluble, but strongly inflatable in the water.

Example 12. A quantity of cotton linen pulp is hydrated by water treatment in a blender, as described above. Then cellulose · was squeezed and divided into 4 portions. One of the portions was dried in vacuo at 3O ... 4O'C with continuous stirring, up to a water content of about 20%. The other three portions were dried under the same conditions, up to water contents of 8 ... 10%, 4 ... 5% and 1 ... 2% respectively. For the last sample, the temperature was slightly higher. Nitrogen amounts of 20 g of each portion, as described above, were nitrified with 30 g of N₂A₄. The reactions of the portions containing 8 ... 10% and 4 ... 5% humidity proceeded quietly and were completed after about 20 ... 30 minutes, forming clear, viscous solutions. Cellulose containing 20% ​​moisture required about 35 g of N₂A₄ and formed a clear solution, soon after adding an excess of 5 g. The cellulose portion with a content of 1 ... 2% moisture required a long mixing time and remained slightly cloudy and with fiber content even after adding a moderate excess of N₂A₄.

By subsequent sulfation, using a complex of Ν, Ν-dimethylformamide - sulfur trioxide, with an SO content₃ about 6 g, were obtained in each case cellulose sulfates with a degree of sulfation of about 0.6, producing clear, shiny solutions in water, when using cellulose with a moisture content of 20%, 8. .10% and 4 ... 5%. However, the reaction products obtained from cellulose, with the lowest moisture content, had a slightly cloudy appearance and fiber content.

Similar results were obtained when, instead of cotton liner pulp, cellulose of hmn or cellulose from vegetable bark or cane was used or when instead of N, N-dimethylformamide, dimethylacetamide or when, instead of the complex of Ν, Ν-dimethylformamide - sulfur trioxide, an egg dioxane complex, dimethylacetamide, dimethylsulfoxide and the like was used.

In another identical series of experiments, in which 20 g cellulose portions were nitrosated, with about 20 g cell. N₂A₄(about 25 g of N₂A₄ egg was needed for cellulose with. (about 20% moisture content) and sulphated with complex of Ν, dim-dimethylformamide - sulfur trioxide containing about 10 ... 12 g of SO₃, the products obtained values ​​of the degree of sulfation of 1.1 ... 1,2, although, from other points of view, the results were similar.

Subsequent nitration and sulfation also proceeded quietly and led to the production of sulphated products which formed clear aqueous solutions, when used directly with linter pulp: cotton or wood cellulose, with a moisture content between about 4%. and about 12%. By simultaneously adding 5%, 10%, or 20% water to anhydrous cellulose, just before the reaction was performed, the results were similar to those obtained in the previous example, with anhydrous cellulose.

Example 13. 5 samples of cotton liner pulp of 20 g each were nitrided, as described above, with about 30 g of N₂A₄ each, and then sulphated with a complex of Ν, Ν-dimethylformamide - sulfur trioxide changing theoretical amounts of SO₃, calculated for values ​​of the degree of sulfation of about 0.4, 0.6, 0.8, 1.1 and 1.6. After neutralization and isolation, the values ​​of the sulfonation degree were about 0.4, 0.6, 0.8, 1.1 and 1.1 respectively. The same values ​​of the degree of sulphatation of about 1.0 ... 1.1 were also obtained when the amount of N₂A₄ it was reduced to 25 g or about 20 g and SO₃ was calculated for a degree of sulfation of about 1.1 and 1.6.

From 20 g of cotton liner pulp, nitrosated with 14 ... 15 g of N₂A₄, was obtained, after sulfation with the theoretical quantity or with a small excess of SO_3t a product with a degree of sulfation of about 1.5 ... 1.6. By increasing the quantity of N₂A₄ at 17 ... 18 g, with the theoretical quantity or with a small excess of SO₃ a sulfation degree of 1.3 ... 1.4 is obtained. However, if about 25 g of N is used in nitrosation₂A₄, sufficient theoretical quantities of SO are sufficient₃ to obtain values ​​of the degree of sulfation of about 0.5 ... 1.1. If, for nitriding purposes, quantities smaller than about 10 g of N are used₂A₄, complete sulfation with the complex ·, Ν-dimethylformamide - sulfur trioxide is not obtained, even if it is used in moderate excess. Similar results were obtained when cellulose made from wood or sugar cane was used instead of cotton liner pulp.

Example 14. 10 g of carboxymethylcellulose with a degree of sulfation of about 1.0 is suspended in about 500 ml of Ν, Ν-dimethylformamide and 7.5 to 8.0 g of N is introduced.₂A₄ in the absence of moisture and with strong agitation. The mixture forms a viscous, light-green solution of carboxymethyl cellulose diazotite.

For the isolation and identification of the ester, the same procedure as that used in Example 1 is used for cellulose nitrogen. If less than N is used for nitriding₂A₄, gra17 · the peak of: nitrosation is correspondingly lower.

.Similar results are obtained when: n-nitrosated under similar conditions, with .can- 'titates: stoichiometric. from N₂A₄, for, to obtain the> complete · or parfia-: esterification of the free hydroxyl groups; methyl cellulose with a degree of sulfation of 1; 0 and 1.5, hydroxypropyl cellulose · egg - a degree of sulfation of 0.8, acidic acid esters at Iginic, with a degree of 'sulfation of -0.5 and 0.8 ; hydroxyethylamidium; · with a degree of sulfation of about 0.2, polyvinyl acetate · partially. hydrolyzed, with 'a degree: of sulfation of 0.4, ester-l-acid', ipectic acids, with a degree of sulfation of 1.2, ΚίΗτοχίθΗ ^ αΓυΐ Αϊ the polysaccharides of. '· salcîm, with a 'sulfation degree' of about 0.4 and 0.7, hemicellulose nitrate with a: sulfation degree of about 0.3, sulfuric ester of polyvinyl alcohol; with a degree of sulfation of 0.3, starch phosphate, · carrageenan. (free acid), gum .χάη-^:hay (free acid) or gumaliaraya. .

Similar results are obtained when instead of Ν, Ν-dime.tilformamide, di-methyl acetamide, pyridine, isoquinoline, -quinoline and others were used; when ·. NOCS was used instead of N₂A₄, with the condition, that the quantity to be triple the quantity: mo'ldfă, of NOCS. ' Of^; Also, the reaction medium may contain substantial amounts of an inert solvent, such as ethyl acetate, ethyl formate, benzene, toluene, dichloromethane, acetone, methylethylketone, and the like, without essential modification of the reaction. .

Example 15. Pour 100 ml of e N, 'N-dimefilformamide · into a vial; 250: rnl, with round bottom, with two necks, equipped with calcium chloride tube and magnetic stirrer. 23. g of N is then added₂A₄ (1/4 mol) with stirring and grinding, obtaining a color solution: dark green. Ld this solution is added slowly, may_;guitars, 12 g of absolute ethyl alcohol (about 1/4 moO). ^!During the addition of the last milliliter, the solution becomes light-yellow, indicating complete consumption of N₂A₄. The solution is then neutralized by the addition of pyridine and subjected to fractional distillation. The first fraction is collected in a · bottle cooled with acetone-ice us-. each consists of about 18 'g of yellowish liquid, with a boiling point of 17 ... 1S ° C. Ethyl alcohol is not recovered during the study.

In the same conditions, it is replaced. ethyl coolant with propqnol, isoprop'ano-1; bu- .tanol, isobutanol, tert-butyl alcohol, amyl alcohol, isoamyl alcohol and hexyl alcohol and 1./8.,mol of ethylene glycol. At fractional distillation, the corresponding nitrogen is recovered, with yields of 80 .. '90%, with. boiling points of about 57 ° C, 45 ° C, 77'C, 68 ° C, 63 ° C, 104 ° C, 99 ° C / Ί30Τ and · -98 ° C respectively. ! rr none of the cases^: some alcohol was recovered.

In another 'series of' experiments, 45 g of cellulose in '100 ml of N, N-dimethylformamide is suspended before addition of N₂A₄"By adding 23 g of N₂A₄, with strong agitation, a solution of triazophil · cellulose is obtained. · To this solution is added alcohol, under the conditions and in the quantities mentioned above - (1 'mol of * alcohol or 0.5 mol of diol per mol of N₂A₄) Separate and remove the free cellulose. The filtrate is neutralized and distilled as described above, obtaining the corresponding alkylazothiites, with yields of 80 ... 85% compared to the theoretical. Similar results are obtained if stoichiometric quantities are used in these residues. methylcellulose, starch, alginic acid: or. polyvinyl alcohol.

in a third series of experiments, on cellulose triazotite solutions, obtained in. the conditions and in the quantities described above, slowly and continuously stirring quantities of the 'complex of Ν, Ν-dimethi'formamide - trioxide' of sulfur, to obtain .-. esters: sulfuric herds of cellulose nitrogen, ,. having sulphate degrees of about 0.4, 0.8 and 1.1. To these ester solutions is added the alcohol, under the conditions and in the quantities described above, the sulfuric ester of cellulose precipitates by addition of acetone in sufficient quantity, and the filtrate is removed. neutralize with pyridine and fractionate distillate. The corresponding alehylazothiites are recovered, with purities and yields similar to those obtained from the triazotite solutions of cellulose from above.

Example 16. Mix 400 g · of cotton swab, with a moisture content of about 5 ... 6%, - with 2.1 'N, N-dime1ylformamide, in an omes ·· double planetary chopper with -draw and in the absence of moisture and add 600 g ds N₂0_;4 .in a period of about 30 minutes to obtain cellulose triazotite. Then add a paste of N, N-dime; iForrnamida - trioxide dc sulfur, containing about 200 g of SO₃, over a period of about 30 minutes and the mixing is continued for a further 10 ... 15 ml n. Slowly add a quantity of 485 g of isobutyl alcohol and the mixture is neutralized (pH = 7., .8) by adding aqueous sodium carbonate solution or a saturated solution of carbonate, sodium or by adding dry sodium carbonate. In this step of 'neutralization' a mixture is required, it has, good and complete the presence of water producing; in gentral, better results. The temperature of the reaction mixture is. maintain below -20 ° C, throughout the reaction, up to 'the completion of neutralization and, until' neutralization, the reaction is exe>

damp in the absence of moisture. The neutral mixture is then strained or centrifuged and if the solids are too much. Soft to be squeezed, add some isopropanol caries to strengthen them sufficiently. The solids are suspended in aqueous isopropanol solution of about 60 ... 70%, dried again, dried and ground. In order to obtain a higher purity, the solids are suspended in aqueous isopropanol solution a second time or, if necessary, a third time, before the final drying and milling.

The filtrates are combined and subjected to fractional distillation, for solvent recovery. One of the fractions distilling at about 66, 67 ° C was identified a^: be nitrogen isobutyl, the yield being over 80%. The brown-crystalline residue from distillation contains the theoretical amount of sodium nitrite. An aliquot sample from it was purified by recrystallization.

In other identical experiments, isobutyl alcohol was replaced with η-propanol, amyl alcohol and ethylene glycol. Instead of isobutyl nitrate, the corresponding nitrites of n-propanol, amyl alcohol or ethifenglicol were recovered, but from the other points of view the results were similar. In another similar experiment, in one isobutane a Iul was replaced with an equivalent amount of water, similar results were obtained, but the solvent recovery residue contained equivalent amounts of sodium nitrite and sodium sulfate with theoretical yields. .

Part of the residue was recrystallized to obtain a purified salt mixture.

Sodium cellulose sulphate had a sulfation degree of 1,0., 1,1 and a 1% aqueous solution had a viscosity of 1 500 ...

000 cP.

in another series of experiments, products were obtained in. similar conditions, but the amount of SO₃ used for sulfation a. has been reduced to obtain products with sulphate values ​​of about 0.4, 0.6 and 0.9. These values ​​of the degree of sulfation were obtained with_;amounts. theoretical SO₃, and the 1% aqueous solutions of the products showed viscosities between about 5000 and approx. ca 2000 cP. In another experiment, the quantity of N₂O »was reduced to about · 300 g and that of SO₃ was increased to about 300 g to obtain sulphates. sodium cellulose with one degree. of sulfation of 1.5 ... 1.6 having viscosities of aqueous solutions 1% of about 600 ... 700 cP.

Equally successful, 1 other cellulose materials, such as wood cellulose or peel cellulose, were used. vegetables, but the final products had slightly lower viscosity of the solutions than those obtained from the cotton liner pulp. Also, the neutralization can be carried out with carbonates, bicarbonates, and hydroxides of other alkaline metals, such as lithium or potassium !, of alloy-, flax-earth metals, such as magnesium! and calcium and manganese, cobalt and nickel, with ammonium hydroxide and amines, in the case of alkali metals, carbonates and bicarbonates are preferred to hydroxides, because of the high alkalinity of hydroxides and the danger of degradation.

According to the present invention, esterified polyhydroxyl polymers are prepared, with new and unique properties, from nitrogen from polyhydroxyl polymers, Nitrites are used as intermediates, because of the instability of the nitrogen groups and because of the solubility of this ester in the environment. In the use of nitrogenous intermediates, polymeric products are obtained, such as nitrates and sulphates of polyhydroxy polymers with new properties and generally with a uniform substitution of nitrate groups. and sulfate, in the polymer units. Due to the relative instability of the nitrite groups, the nitrogenous polycrystalline polymers can also be used for the manufacture of films, fibers and other shaped articles, consisting of homogeneous mixtures of different polyhydroxyl polymers or mixers of one or more polymers or more polymers. many other polymers.

When esters of polyhydroxide polymers are formed, the amount of depolymerization resulting from the reaction is negligible. Thus, products that produce solutions with very high viscosities are obtained. In the case of sulphates of polyhydroxyl polymers, for example, solutions of products with viscosities several times higher than the viscosities of sulphate solutions, obtained by known processes were obtained. In the present invention it is possible to obtain esterified polyhydroxyl polymers, with degrees of substitution which cannot be obtained by the known methods. For example, cellulose sulfates with low substitution degrees below 0.3 were obtained, where ester groups are uniformly distributed in the cellulose polymer units. Sulfuric acid esters of polysaccharide were also obtained. from acacia and greyhound, with a substitution degree greater than 1. Water-soluble nitrates of polyhydroxyl polymers with a lower substitution degree have also been prepared. 1. The properties of these nitrates are, in particular, special, as the nitrates of polyhydroxyl polymers known so far are, in general, strongly substituted and insoluble in water.

The uniformly-relative distribution of the substituent ester groups in the molecule results, in part, from the fact that the nitrogen intermediate used in the reaction is solvated or even dissolved in the reaction medium. In contrast to the present process, in the known processes, the polymeric raw material is generally suspended in the reaction medium in the form of insoluble particles. The homogeneity of the products, prepared according to the present invention, is of particular importance when the degree of substitution of the esterified products is considerably lower than the maximum degree of substitution of the polyhydroxyl polymer, such as in sulphates and, in particular, in sulphates! of cellulose. For example, in known sulfation processes, such as preparation, cellulose sulphates, insoluble cellulose fibers are used as starting material. When sulphating the fibers, the reaction mechanism involves a simplified process of "peeling," in which, firstly, the surface of the fibers is partially substituted, which is then solvated and removed by the reaction medium, and then it is strongly substituted by reaction with the reactant. excess sulfation in the reaction medium. During the process of peeling, the next inner layers of cellulose fiber are similarly exposed and sulphated, the process containing until most of the fiber or reactant is consumed.

As a result of the "peeling" process, the polymeric sulphates obtained so far are strongly substituted and have a degree of substitution very close to the maximum, regardless of the amount of sulfating agent used. Even when the average degree of substitution has! the polymer is smaller than the maximum degree of substitution, the distribution of the substituent ester groups is not uniform and a considerable number of polymeric units are completely substituted, while other polymeric units have a very low degree of substitution or are not substituted at all. These disadvantages are eliminated in the present invention, as the nitrogen used as an intermediate is solvated or solubilized and the substituent ester groups in the final products are thus evenly distributed in the polymer units of the product. Thus, taking the cellulose sulphate products of the invention, with a substitution degree of 2 or 1, in essence, all the polymer units in the cellulose molecule contain only 2 groups of sulphates or only one group of sulphates.

Due to the uniform distribution of the ester groups in the polymeric units in the products, they generally have unusual solubility characteristics. Also, the solutions of these products have unusual properties with metal ions. For example, cellulose sulfates, obtained according to the invention, which have substitution degrees of about 0.3 to about 1, are water soluble. This is surprising, since the known colloidal cellulose sulfate must have a substitution degree greater than 1 in order to be soluble in water, in addition, the sulfates of the polyhydroxyl polymers of the present invention are also different from apparently similar, known materials, in terms of compatibility with a variety of metal ions and also in terms of compatibility with relatively high concentrations of metal ions. There are also other differences between the products of the present invention and similar known materials, for example sulfates of polyhydroxy polymers, in terms of reactivity to water soluble proteins.

The present invention relates to a process for the preparation of sulphates of polyhydroxy polymers, respectively of polysaccharides or polyvinyl alcohol, partially substituted, with ether or ester groups. Etherified or esterified polyisinides or polyvinyl alcohol are known materials, which include, for example, substituent groups such as formate, acetate, carboxymethyl, methyl ether, ethyl ether and propionate. Typical known etheric or ester materials that can be used as starting materials are: carboxymethyl cellulose, methyl cellulose, hydroxyethikellulose, alginic acid acetate, alginic acid propionate, starch phosphate, hydroxypropyl agaric, poetic acid butyrate, carboxymethyl acetate [amide] partially hydrolyzed polyvinyl, natural sulfates, such as carrageenan, natural acetyl esters such as karaya gum and xanthan gum, etc.

For the preparation of nitrates or sulphates of polysaccharides or polyvinyl alcohol, etherified or estenified, it is necessary that the reactants contain free hydroxyl groups. Thus, polyether vinyl alcohol or etherified or esterified alcohol, used as starting materials are only partially substituted and contain free hydroxyl groups, which are used as reactive groups according to the present invention. The free hydroxyl groups of the etherified or esterified starting materials can thus be nitrosated, nitrated and also sulphated similar to the nitrosated, nitrated and sulphated unsubstituted polyhydroxy polymers to obtain the corresponding esters of partially etherified polyhydroxy polymers.

Nitrogenous polyhydroxy polymers, used as reaction intermediates in the present invention, are prepared by nitrosating a suspension of the desired polyhydroxy polymer,

70 171 used as a starting material in a suitable organic solvent, at a reaction temperature below about 50 ° C. The reactant of. nitrosation is preferably nitrogen tetraoxide, which is in equilibrium with nitrogen dioxide, the monomer. or. By using nitrogen as a reaction intermediate, nitrogen and sulfate can be easily synthesized according to the invention. The obtained nitrates and sulfates have a negligible · depollmerization degree and a selective esterification degree. Also, the nitrogen and sulphate obtained are distinguished by. homogeneity of the substitution, which means that the ester groups, for example sulfate groups, are distributed relatively homogeneously in the molecule. Thus, the properties of the products differ substantially from the properties. products apparently similar, known, in that they have higher viscosities · and some metal ions are compatible.

The polymeric sulphates are prepared according to the present invention, by suifatation of a polysaccharide azofif or polyvinyl alcohol with sulfur trioxide or a complex thereof, at a relatively low reaction temperature. Then the residual nitrite groups are removed from the polymer, by reaction with a propane solvent, to obtain a relatively non-degraded sulfuric, polymeric, ester, and the sulfuric ester can then be neutralized or slightly alkalized to obtain the more stable salt form of the sphere. . The alkaline salt of the non-degraded ester is very soluble and its aqueous solutions have a high viscosity. Thus, sulphate salts are used as thickening agents in aqueous media.

Typical known polyhydroxyl pblls that can be used as raw materials are¹ polysaccharides such as cellulose, starch, herofcellulose, agar, acacia polysaccharides, gum arabic and mannies, polyuronic acids represented by alginic and poetic acids and synthetic hydroxyl polynomial polymers, as. would be the aicool. Polyvinyl. Partially etherified or esterified polyhydroxyl polymers as described above are used as starting materials in the preparation of nitrate or sulphate, partially substituted polyhydroxyl polymers.

Polyhydroxyl polymers used as materials; primers are suspended in a suitable solvent, which includes a swelling or softening agent for the polymeric reaction product and a propane acceptor. Suitable solvents, both as proton acceptors and as inflating or solubilizing agents, include weak tertiary amines, such as pyridine, quinoline, and isoquinoline, and also N, N-dialkylacylamides, such as Ν , Ν-dimethylformam'ida and N, N24

-dimethylacetamide, as well as their mixtures. Suitable swelling or solubilizing agents are generally solvents capable of dissolving polymeric esters. Typical examples of such swelling or solubilizing agents are ethyl acetate, ethyl formate, benzene, acetone, methylethylketone and the like, as well as mixtures thereof. Suitable compounds as proton acceptors are compounds capable of producing the swelling or solubilization of polymeric nitrogen and also acting as proton acceptors.

The amount of solvent that can be used to suspend the polyhydroxyl polymer is not critical and can vary over a relatively wide range. However, a sufficient amount of solvent must be used to avoid difficulties in handling the resulting viscous mixture. In general, it has been observed that the minimum weight to solvent ratio of the polymer must be 3. · 1, respectively three parts by weight of solvent for each part by weight of the polymer, in general, it is preferable that the solvent be capable of to inflate as well as to solubilize the nitrogen of the resulting polyhydroxy polymer, and also to act as a proton acceptor. When using a mixture of proton acceptor and inflator or. of solubilization, the use of a single solvent is more economical, as it simplifies · the recovery and reuse of the solvent. However, when using a proton acceptor mixture with a swelling or solubilizing agent, the mixture must contain at least one mole of proton acceptor for each mole of nitrosating agent, for example nitrogen tetraoxide.

As mentioned, during nitration or suifatization of a nitrite, the product obtained is a new polysaccharide or a new polyvinyl alcohol, substances containing a mixture of nitrogen groups with sulphate or nitrate groups, this mixture being uniformly distributed in the units. polymers of polysaccharide or polyvinyl alcohol. These new products are valuable intermediates for the preparation of polysaccharide sulphate or nitrate or polyvinyl alcohol, wherein the ester groups of sulphate or nitrate are uniformly distributed in the polymeric units of polysaccharide or polyvinyl alcohol.

The use of polysaccharide or polyvinyl alcohol azophytes as feedstocks for the preparation of other polysaccharide esters or polyvinyl alcohol is of particular importance for the preparation of cellulose sulphates. By controlling the degree of substitution of cellulose azotif, used as a raw material, the degree of substitution of the obtained cellulose sulphate can also be controlled. Thus, when cellulose nitrogen has a substitution degree of 2 to 3, cellulose sulphate, obtained by the process according to the invention, will have a substitution degree of up to approx.

1.1, However, when cellulose nitrile has a substitution degree less than 2, cellulose sulfate will have a substitution degree greater than about

1.1. In each case, the sum of the degree of substitution of cellulose sulphate and the degree of substitution of cellulose azo-oxide is approximately 3.0.

Another aspect of the invention relates to the new water-soluble cellulose sulphates, with a substitution degree of about 0.3 to about 1.0, in which the sulfate groups are uniformly distributed in the polymer units of the cellulose. The water solubility of these materials is surprising, as cellulose sulfate prepared by other known processes is not soluble in water unless the degree of substitution is greater than 1.0. These water-soluble cellulose esters can be used to obtain thickened aqueous media, do they contain water and water-soluble cellulose sulfate, with a substitution degree of about 0.3 to about 1.0, having the sulfate groups evenly distributed in the polymer units of the cellulose, the sulphate being found to be effective in thickening the aqueous environment.

Another aspect of the invention relates to cellulose esters insoluble in water, but which. however, they are strongly inflatable in the presence of water. These cellulose sulphates, insoluble in water, have a substitution degree of less than about 0.3, the fiirid sulphate groups also uniformly distributed in the polymer units of cellulose. The inflatability in the water of these materials is quite unusual. Due to the unusual properties of cellulose esters, which are inflatable in water, having a substitution degree of less than about 0.3, these materials acquire new uses in the preparation of absorbent materials, such as towels, towels and others.

Another aspect of the invention relates to the polysaccharide or polyvinyl alcohol nitrates, which have substitution degrees of less than about 2.0. In particular, cellulose nitrates having a substitution degree of less than 2.0 have a special value, since they can be used to obtain cellulose sulphates, as mentioned above, with substitution degrees of about 1.1 to at 2.0, the sum of the degree of substitution of the nitrogen groups and the degree of substitution of the sulphate groups in the mixed ester, the precursor, being equal to the airca 3.0.

Another aspect of the present invention relates to the process for the preparation of cellulose azophytes. As described, the use of cellulose nitrogen as an intermediary makes it possible to prepare new cellulose esters, such as cellulose sulfate or cellulose nitrate, in which the properties of the final product can be attributed to the uniform distribution of ester groups in the polymer units of cellulose. . It has been observed that cellulose nitration with nitrogen tetraoxide or nitrosyl chloride and subsequent sulfation, as described above, can be further improved if the cellulose reagent is in the activated state. According to this improved process, the cellulose is in a hydrated state and contains from about 4 to about 12% by weight of water, the water being evenly distributed in the mass of the cellulose reagent.

By using the hydrated cellulose reagent, the nitrosating reaction can be effected in a shorter time, using essentially stoichiometric quantities of the nitrosating reagent. This results in a more homogeneous reaction mixture and a high clarity product, thus allowing easier separation of the product from the reaction mixture and reducing the need for filtration.

Another aspect of the invention relates to a variant of the improved nitrosation process, wherein the cellulose reagent is uniformly hydrated. In this embodiment, the hydrated cellulose, which may contain an excess of about 4% by weight of water, evenly distributed in the cellulose mass, is washed with a strong polar solvent, to reduce the cellulose water content to less than about 4%. by weight. Surprisingly, it has been observed that cellulose remains in the activated state after washing the aprotic solvent, even though the washed cellulose has a water content of less than about 4% by weight. The washed cellulose can then be used in the manner described above, in nitrosation with nitrogen tetraoxide or with nitrosyl chloride.

It has been observed that the substituent groups of nitrite, which are found in the nitrogenous polyhydroxyl polymers, for example cellulose or. mixture of nitrite / nitrate or nitrite / sulfate of polyhydroxyl polymer are surprisingly labile. Thus, unlike other nitrogens, the substituent groups of nitrite from cellulose (or other polyhydroxyl polymers) can be readily removed to form alkyl-nitrates during the formation of nitrates or cellulose sulphates from cellulose nitrates, asylproducts. when obtaining cellulose nitrate or cellulose sulfate.

70171

In the formation of an alkyl nitrite as a by-product, an alkyl alcohol is added to the reaction mixture containing a nitrogen / nitrogen or nitrite / sulfate mixture of a polysaccharide or a ροϊ-ΐν-ΐηϊlic alcohol, whereas a nitrogen or of sulfation is generally formed the mixed ester, in the reaction mixture from the obtaining of nitrogen, the nitrogen tetraoxide can be released and can be found in the reaction mixture. When the alkyl alcohol is added, the alcohol reacts with both the free nitrogen tetraoxide and the labile nitrogen groups of polysaccharide or polyvinyl alcohol. The reaction of teiraoxide by nitrogen egg, the aqueous alcohol, leads to the formation of elcS-nitrites by direct nitrosation, comparable, as a mechanism, with the reaction of the nitrogen oxide with a polysaccharide or with polyvinyl alcohol, to the formation of nitrogen. However, the reaction of substituent nitrogen groups, from polysaccharide or from polyvinyl alcohol, with alkyl alcohol occurs by transesterification rather than by direct nitrosation. Although unconnected with any theory, it seems. that the transesterificars reaction favors the production of the most stable nitrogen in the system, which, in this case, is the alkyl-sulfite which is produced quantitatively.

Whatever the reaction mechanism, the most important thing is that both the free nitrogen tetraoxide and the nitrous substituent groups dir> polysaccharide or in the polyvinyl alcohol quantitatively form the same alkyl-nitrogen, so that the excess of. Nitrogen tetraoxide enters the production of the valuable by-product, alkyl nitrogen.

As. Alkyl alcohol can be used in various alkanols and alkandies such as; propanol, butanol, amyl alcohol, ethanediol, 1,2-propcindiol, etc. In addition, higher alcohols, such as decanol, can be used, containing up to about 10 carbon atoms. Also suitable for the reaction are primary alcohols, such as butanol, secondary alcohols, such as isopropanol, and also tertiary alcohols, such as tert-butyl alcohol. For the purpose of quantitative reaction of nitrogen tetraoxide, the alkyl alcohol must be in an amount of at least one mole of alkanol or half a mole of alkanoyl, for each mole of nitrogen tetraoxide initially added to the formation. of polysaccharide nitrite or polyvinyl alcohol, the alcohol being added after the formation of the mixed ester of! polysaccharide or polyvinyl alcohol.

as the alkyl azophytes are relatively stable in. comparison with · polysaccharide or polyvinyl alcohol nitrates, the following reaction steps for the formation of nitrate or sulfate, respectively neutralization,

2j separation and isolation of nitrate. or the resulting polysaccharide sulphate or polyvinyl alcohol, can be made without too clever removal of the alkyl nitrite. Thus, for example, for the formation of the mixed nitrogen ester / cellulose sulfate, with the subsequent addition of the required amount of alcohol, the resulting cellulose sulfuric ester may be precipitated by addition of acetone to the reaction medium, followed by removal of the precipitate by. further processing. Alkylazotite remains in the filtrate and both solvents and alkyhazotite can be easily recovered by fractional distillation or by other means: suitable. As the filtrate is alid, it may be neutralized to a suitable base, before distillation, to reduce the decomposition of the various compounds. One way to reduce decomposition is to perform distillation under reduced pressure.

In order to separate the ester, for example from the sulfuric ester ah cellulose, it is generally preferred to neutralize the entire mass of the reaction mixture without prior isolation of the ester. This allows a great deal of solvent to be saved, not necessarily the alkyl-nitrogen decomposition, in this way the product is recovered. Thus, after the addition of alkanol or alkanediol, a suitable base, such as an ammonium salt or an N-substituted ammonium salt, is added, hydroxides, carbonates or bicarbonates alkali or alkaline-earth, in the form of an aqueous solution, or in the form suspension of an excess of base in its saturated solution, with continuous stirring of the reaction mass during addition of the base. Preferred bases are alkaline carbonates and alkaline bicarbonates, which can also be added in the form of dry powder. To prevent any degradation of the polysaccharide ester or polyvinyl alcohol obtained, for example cellulose sulfate, the reaction mixture is preferably kept at a temperature of less than 15 ... 20¾ until the neutralization is completed.

If the concentration of solids in the reaction mixture is high enough and the concentration of water in the mixture is relatively low, cellulose sulphate can be found in a solid, moist form, and can be easily separated. If, however, cellulose sulfate is found as a paste after neutralization, a sufficient amount of miscible egg water solution, such as acetone, methanol, ethanol or isopropanol, is added to obtain the separation of the product, after which it may be separated, dried and dried or purified. If the product is directly dried, the resulting product is a technical product, of relatively crude quality, which confines salt as the main impurity. The purified product can be. prepared by extracting moist solids, once or more often, with an aqueous solution of another ^scool, such as methanol, ethanol or isopropanol! containing about 20 ... 40% by weight water, followed by drying the product, at high temperature. Of course, it is. as far as possible, to extract 'θ the dry technical product, with an aqueous alcoholic solution to obtain a purified product.

As described above, the filtrate can confine both solvents and alkylates. ¹⁵rumbling, both of which can be easily recovered by distillation. In the case of the higher alkyls, for example with more than about 7 carbon atoms, some of them may remain together with the solids,²⁰because of their low solubility, in the aqueous alcoholic solution. In this case, a final extraction with anhydrous alcohol or an alcohol with a water content of less than about 20% can be performed. A-25 will completely separate the nitrogen-alkyls, resulting in higher yields during distillation. In addition, it is also possible to dry solids in a closed system so that all absorbed solvents, including alkyl azorite, can be recovered! retained.

A second by-product that can be formed in equivalent quantities is an inorganic nitrate, for example, nitrogen nitrate. ³⁵sodium, in the case of the use of sodium hydroxide or sodium carbonate, when neutralized. If it is not desired to obtain an alkyl nitrite simultaneously with the inorganic nitrogen, to the mixture of⁴⁰an equivalent amount of water can be added instead of the alcohol. This will lead to the formation of equivalent amounts of inorganic nitrate and inorganic nitrogen, for example a-⁴⁵rubbed with sodium and sodium azoiite. Both salts will be found in the filtrate and will remain in the residue after the solvent recovery. The salts can be purified by crystallization or by other known methods.⁵⁰you, to obtain salts of medium, or high purity. However, if the salts are to be used as fertilizers, purification is not necessary.

The first step of the process of the invention ⁵⁵consists of the nitrosation of a pollen hydroxyl polymer suspended in a suitable solvent, with nitrogen tetraoxide, nitrosyl chloride or mixtures thereof, to obtain the corresponding nitrogen of the hydroxyl polymer ic.

The nitrosating agent is used in the mixture! of reaction in a molar ratio between anhydroglucose or unifold poly- 6?

general limerica and nitrogen tetraoxide or nitrosyl chloride about! : 0.1 to 1: 3, resulting in a degree. of substitution from 0.1 to 3. Since the reaction-. is quantitative, the degree of substitution coincides approximately with the molar amount of de-nitrosating agent used. If chloride is used; nitrosyl together with dimethylformamide or dimethylacetamide, to obtain the same degree of substitution it is necessary to use an excess of. nitr-ozore agent 2.5 ... 3.0 times higher. In other words, a nitrogen tetraoxide or nitrosyl chloride mole is required to replace a mole of hydroxyl radical in the polyhydroxyl polymer, if nitrosyl chloride is used together with a Ν, Ν-dialkylacylqmide as a proton acceptor , with a ratio of 2.5 to 3.0 mol of nitrosyl chloride.

The maximum degree of substitution of hexozanes, such as cellulose, starch, agar, acacia gums, peanuts and others, is about three, of pentozanes, such as hemicellulose and polyuronic acids, for example alginic acid and pecic acid. , is about two and polyvinyl alcohols here is about one or less. Thus, the molar amount of nitrogen tetraoxide required to obtain complete esterification of hexozanes is about three mol per mole of anhydrohexane unit, of penan-oxides and polyuronic acids is about two mole per mo! of anbidropentose or uronic acid unit, and of polyvinyl alcohols is about one mole or less, depending on the degree of saponification;

Maternal re p rime, · The same molar ratio of nitrosyl chloride is required J for the complete esterification of each of the classes of polyhydroxyl polymers desorbed above, apart from the case of use of dimethylformamide or di- ί meylacetamide. In the latter case, the quantity of the juice should be substantially triple;

your. An amount of nitrosating agent may be added greater than the amount required for complete esterification, single egg:

the effect of increasing the speed of esterification. :

The nitrosation reaction is preferably carried out with constant stirring of the reaction mixture. It is necessary that the nitrosating agent be introduced into the polymer suspension in the absence of moisture. It is preferable to cool the reaction vessel on an ice bath, as the reaction is moderately exothermic, and it is also desirable that the reaction mixture temperature be kept below 50 ° C.

If maximum esterification is desired, the end of the reaction is indicated by the formation of a clear solution or a paste, while in J the partial esterification is indicated by the partial swelling and / or dissolution of the product in the reaction mixture.

Polymeric nitrites are relatively sensitive products and decompose immediately upon addition of a protic solvent, such as water, methanol, ethanol, isopropanol and the like, in the presence of a mineral acid, as a catalyst. This results in the regeneration of the non-degraded polyhydroxyl polymer, used as a raw material.

Since the polymeric nitrates of the invention are primarily used as intermediates for obtaining other esters, such as nitrogenous and polymeric sulphates, it is not necessary to isolate the nitrites from the reaction mixture, as they can be used in the processes for obtaining such esters. it was mentioned. However, the polymeric nitrogen can be isolated by neutralizing the reaction mixture by adding a base, such as mono-, di- or trialkylamines, pyridine, hydroxides, carbonates, bicarbonates! alkaline or alkaline-earth metals and others. The addition of the base is only required when using a Ν, Ν-diacylaciamide as a proton acceptor, due to the formation of an equimolar amount of nitric acid or hydrochloric acid during nitration with nitrogen tetraoxide or nitrosyl chloride. In the case of the use of a weak tertiary amine base, such as pyridine or quinoline, as a proton acceptor, the addition of a base is not necessary, as the acid formed is neutralized by the tertiary amine and cannot serve as a catalyst for decomposition of polymeric azotituiui.

The neutralized or preferably weakly alkaline solution is then poured into ice water with stirring to separate the polymeric nitrogen as a fibrous material, which can be easily separated. Products with a considerably lower degree of substitution than the maximum may be inflatable or even water soluble, in which case an alcohol is used instead of water.

The isolated product is relatively unstable, which is why for storage purposes it is preferable to solvate it in a suitable solvent, such as benzene, ethyl acetate], dichloromethane, dimethylformamide, dimethylacetamide, or the like, storing at room temperature. low, preferably below 1 ° C.

For the formation of polymeric sulfate, the second step of the process of sulfation of the polymeric nitrite solution is passed, preferably with a low temperature sulfur trioxide complex, to obtain a mixed nitrogen / sulfuric ester.

The polymeric nitrite solution preferably contains the reaction mixture from the first step, in which an N, N-dialkylacylamide was used as a proton acceptor. The temperature of the reaction mixture should be maintained in the range of about 0 to 25 ° C and preferably 5 to 15 ° C to avoid depolymerization of the molecule during sulfation.

The preferred sulfating agent is sulfur trioxide, which can be added to the reaction mixture in liquid or gaseous form or in solution form, in an inert solvent, such as carbon tetrachloride. However, since the addition of sulfur dioxide is exothermic, when a low reaction temperature is critical, in order to obtain the desired viscosity of the product, the sulfur trioxide must be added slowly, with stirring and with the reaction mixture being kept in a cooling medium. , such as an ice bath.

In practice, it is preferred that the sulfating agent first be added to a solvent, preferably a solvent identical to that contained in the reaction mixture for ease of solvent recovery, to form a complex which, upon addition to the reaction mixture, produces a less exothermic reaction. Examples of capable solvents_eto form a complex with sulfur trioxide are: dimethylformamide, dimethylacetamide, dioxane and pyridine. In general, the molar ratio of sulfur trioxide to solvent in the complex is 1: 1. However, it is preferable to use an excess of solvent to obtain a suspension or a complex solution in the solvent.

The complex is added slowly, to the reaction mixture, with stirring and in the absence of moisture. The amount of sulfating agent that is added to the mixture depends on the degree of substitution desired in the final product. A reduced degree of substitution, between 0.1 and 1.0, requires about 0.1 to about 1.0 mo] of sulfur trioxide per mole of anhydroglucose unit. A substitution value of from about 1.0 to about 2.0 requires about 1.0 to 4.0 mol of sulfur trioxide for the anhydroglucose unit. A substitution degree greater than 2.0 is difficult to achieve under the reaction conditions, with a large excess of sulfur trioxide required.

By adding the sulfating agent to the polymer nitrogen mixture, a mixed nitrogen / sulfuric polymeric ester is obtained. Although polymeric nitrogen with a maximum substitution degree can be used for sulfation, to obtain products with a sulfation degree of up to about 1.1, it is preferable to use polymeric nitrates with low substitution degrees, for economic reasons, in the species! in the. if substitution degrees greater than 1.1 are desired. The cellulose, of exernpio, can be easily sulphated to a degree of substitution between about 1 and 2 only when the degree of nitration is between about 2 and 1, However, if the degree of nitrosation falls considerably below 1, the sulphate becomes increasingly difficult and incomplete and the distribution of increasingly uneven sulfate groups. Generally, the higher the degree of sulfation desired, the lower the degree of nitration, so that the mixed nitrogen / sulfuric polymeric ester has a maximum degree of substitution. In other words, the sum of the degree of nitrosation and the degree of sulfation must be about 3, for hexozanes, about 2, for pentoses and polyuronic acids and about 1 or more, for polyvinyl alcohols.

The next step of the process consists in treating the nitrogenous / sulfuric mixed polymeric ester with a protic solvent to obtain the corresponding sulfuric ester of the polymer.

By adding a protic solvent, such as water, methanol or ethanol, the pure sulfuric ester of the polymer is obtained. The protic solvent replaces the nitrogen groups in the product with hydroxyl groups; it is added in stoichiometric quantities or in excess.

To isolate the obtained polymeric sulphate, add 2 to 4 vol to the mixture! of water-miscible solvent, for example acetone, to separate the sulphate from the amesiac, the ester is removed and washed with fresh solvent, then dissolved in ice water again.

The next step of the process consists in neutralizing the sulfuric ester of the polymer with a base, to form a salt thereof.

The isolated sulfuric ester degrades upon storage and, therefore, it is preferable to convert from a neutral salt. Preferred bases for sulfate neutralization are hydroxides, carbonates and bicarbonates of alkaline and alkaline-earth metals, ammonium hydroxide and amines can also be used for this purpose. The resulting salt is isolated by adding the neutralized mixture, with stirring, to a water miscible solvent, such as acetone, methanol, ethanol and isopropanol, or vice versa. The isolated product can be washed with an aqueous solution of a solvent and dehydrated by washing with an anhydrous solvent. The separated polymeric sulfate salt can then be removed and dried for storage.

Instead of neutralizing an aqueous solution of the isolated sulfuric ester, the reaction mixture from the previous step, consisting of the sulfuric ester and the protic solvent, can be directly neutralized to obtain the sulfate salt, in this case, the base may be added as a solution. aqueous or in the form: dry. In the neutralized mixture, the product can be found in wet but solid form, it can be separated directly by centrifugation or filtration, dried and dried, to obtain a product of technical quality, which contains salts as impurities, the pure product can be obtained by washing the product damp, once or more times, with an aqueous alcoholic solution, before drying. If there is a relatively large amount of water in the neutralized mixture, the product is too soft to be collected or even partially dissolved. In this case, a sufficient amount of alcohol is added to harden the product or precipitate it, so that it can be separated by filtration or centrifugation.

The product is water soluble and, since it does not depolymerize, a 1% aqueous solution is a very viscous and very stable solution. Sodium cellulose sulphate becomes water soluble if its degree of substitution exceeds about 0.3 and has a high viscosity of 8000 ... 9000 cP.

As a result of these unique physical properties, the products are useful as thickening, suspending and emulsifying agents. In general, the viscosity decreases somewhat as the degree of substitution increases, simply due to the increased molecular weight of the polymer. However, in application, in bone glue, it is preferable to use a product with a substitution degree greater than about 1.0 for which, in this particular case, the best results are obtained with products with degrees larger substitutions.

The process, according to the invention, has the advantage that it allows to obtain products useful as thickening, suspending and emulsifying agents.