Process for the bulk separation of inositol and sorbitol by se-lective adsorption on zeolitic molecular sieves

DESCRIPTION OF THE INVENTION for

PROCESS FOR THE NET SEPARATION OF INOSITOL AND / OR SORBITOL BY ADSORPTION

SELECTIVE FOR ZEOLITE MOLECULAR Sieves featuring

UNION CARBIDE CORPORATION, North American (New York State), industrial, established in Old Ridgebury Road, Danbury, Connecticut 06817,

USA

RESUME

The present invention relates to a process for the liquid phase separation of inositol and / or sorbitol comprising its selective adsorption by certain types of zeolite molecular sieves. The process is especially useful for separating inositol from aqueous solutions containing it, using type X and type Y zeolite additives whose cations are Na,

Ca or Ba.

GENERAL BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a process for the liquid phase separation of inositol and / or sorbitol from mixtures containing these compounds. More particularly and according to a preferred embodiment, the present invention relates to such selective adsorption separation by

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certain types of zeolite molecular sieves.

Description of the Prior Art

Both inositol and sorbitol are sugar alcohols that have a higher commercial value than ordinary sugars. Inositol is a generic name for a family of cyclohexanehexols (hexahydroxycyclohexanes) of formula

O₆B₆(OH)₆ that there are nine possible stereoisomers. Of these possible isomeric forms, one occurs predominantly in nature and is known by several names including meso-inositol, myo-inositol, i-inositol, inosite, dambose, meat sugar or muscle sugar. Myo-inositol is a commercially important compound and has a number of physiological activities. A member of the Vitamin-B complex, in which it has the activity of being growth factor for certain animals and microorganisms. It is also a factor in regulating fat and cholesterol metabolism in higher animals. For convenience only, myo-Inositol will be referred to herein simply as inositol. Furthermore, while the present invention has been found to be useful for the separation of myo-inositol, it is expected that other isomers of inositol other than myo-inositol may be separated by the same process. For a fuller description of inositol and its properties see Encyolopedla of Chemical Technology by Kirk-Othmer, 2 &amp;. Edition, Volume 11, (1966), p. 673-676.

As far as the Applicant knows, no commercial process for the production of inositol by synthesis is known. However, as it exists to a large extent in living cells, it is possible to extract inositol from plants. Inositol exists in free form in many fruits; for example, about 8% by weight of soluble carbohydrates in almond shells and about 1.2% by weight of lorantacene fruits is inositol. 0 Inositol also exists as hexaphosphate (ie phytic acid) in the seeds of many plants. For example, about 25% by weight of the water solids of

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Corn maceration (by-product of wet corn processing) is phytic acid and inositol is currently produced on a commercial scale from this maceration water. Specifically, phytic acid, which has the following composition (as acid)

O₆^H5 / BK) (0H)₂ 7g is primarily precipitated as calcium / magnesium salt. The salt is hydrolyzed to inorganic phosphate and inositol, with inorganic phosphate precipitated out and inositol recovered by repeated crystallization. This process is expensive and costly, involving digestion at 100-200²C in acids or bases, etc.

Sorbitol can be prepared by reducing sugars and is a commercially important polyfunctional alcohol in its pure form. Sorbitol has many applications, for example it is used as a wetting agent in cosmetics or can be used to make polyesters that are useful in plastics.

Co-pending Patent Application Serial Number 329 608, filed December 10, 1981 (D-13 261). Applicant discloses a process for the liquid phase separation of sorbitol and mannitol by selective adsorption by certain types of zeolite molecular sieves. Specifically, Table II on page 7 indicates sorbitol selectivity of various cationic forms of type X and type e zeolite.

SUMMARY OF THE INVENTION

The present invention, in its broadest aspects, relates to a process for the liquid phase separation of inositol and / or sorbitol from solutions containing them by selective adsorption through X-type zeolite molecular sieves. or type Y with the exchanged cations. The process generally comprises contacting the solution at a pressure sufficient to maintain the liquid phase system with an adsorbent composition comprising at least

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a crystalline aluminosilicate zeolite chosen from the group consisting of type X zeolites and type Y zeolites, wherein the zeolite cations are selected from the group consisting of sodium, barium and calcium, so as to selectively adsorb inositol and / or sorbitol ; removing the non-adsorbed portion of the solution from contact with the adsorbent; and desorbing the adsorbed from it by contacting it with a desorbent agent and recovering the unsorbed inositol and / or sorbitol.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is an elution curve of a mixture of sugars and sugar-alcohols wherein the adsorbent is sodium-substituted Y-type zeolite.

Figures 2-4 represent elution curves of the same sugar / sugar-alcohol mixture in which the adsorbents used are, respectively, barium-substituted adsorbents and sodium-substituted barium-zeolite type X adsorbents.

Figure 5 is a diagram of a method using the process according to the present invention.

DESCRIPTION OF EMBODIMENTS

Preferred

The present invention provides a process for the liquid phase separation of inositol and / or sorbitol from feed solutions containing them. The feed solution may, for example, be a mixture of sugars and / or sugar-alcohols such as liquid fruit extract; or the feed may comprise a sugar-alcohol mixture only or a mixture of inositol and / or sorbitol with other carbohydrates. 0 The solvent used to prepare the feed solution is not a critical factor and can be any substance that has a reasonable ability to dissolve the carbohydrate species involved, is a liquid and is chemically inert to the adsorbent and essential compounds of the product. solute under the adsorption conditions imposed to carry out the separation process. Water is the preferred solvent but alcohols, ketones, esters and the like may also be employed.

The present inventors have been informed of the existence of a proposed process which, in part, applies the selective adsorption aspects of the present invention to recover inositol from almond shells by treating an aqueous extract thereof. As inositol can constitute as much as 8 percent by weight of the soluble carbohydrates in almond shells, an aqueous extract thereof which also contains significant amounts of sorbitol, sucrose, glucose and fructose is the preferred feed material for use in the process. according to the present invention when the adsorbing agent has a marked preference for inositol or sorbitol. Although the present invention is generic to appropriately treatable feed materials, the specific embodiment utilizing the almond peel extract does not therefore fall within the scope of the present invention.

Carbohydrates which, together with inositol and / or sorbitol, constitute the solutions suitably treated using the present process are well known in the art; are any well-known monosaccharides, disaccharides and even polysaccharides, of which lactose, maltose, sucrose, mannose, galactose, alulose, fructose, sorbose and starch are representative. Other sugar alcohols such as mannitol, xylitol, ribitol and iditol may also be present and are considered to be carbohydrates for the purposes of the present invention but are not, strictly speaking, true carbohydrates.

Zeolite molecular sieves (hereinafter referred to as "zeolites" herein) are crystalline aluminosilicates which have a three-dimensional structure and contain interchangeable cations. The number of cations per unit cell is determined by their silica to alumina ratio and the cations are distributed in the channels of the zeolite structure. Carbohydrate molecules may diffuse into the zeolite channels and then interact with the cation and be adsorbed to the cations. Cations are, in turn, attracted by the aluminosilicate structure which is a

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gigantic anion multiply charged. The selectivity of zeolite adsorption depends on the concerted action of electrostatic field intensity, cation radius, channel size, shape and cation density and spatial distribution. As spherical effects play an important role, the adsorption selectivity of zeolites is highly unpredictable.

The Applicant has found that while most zeolites do not adsorb inositol, NaX, BaX and BaY zeolites adsorb particularly intense inositol substantially more than sucrose, fructose, glucose or sorbitol. They are therefore particularly suitable for inositol recovery. The Applicant also found that the CaX and CaY zeolites have different adsorption selectivities for the five carbohydrates mentioned above but it is sorbitol and not inositol which is the most intensely adsorbed compound. CaX has the following selectivity sequence: sorbitol, inositol fructose, glucose, sucrose.

CaY has the following selectivity sequence sorbitol&gt; -inositol = fructose&gt; glucose&gt; sucrose. The distinctive CaX selectivities allow the adsorbing agent to be used to isolate both sorbitol and inositol from the other three compounds by chromatographic elution. However, while CaY itself can be used to separate sorbitol, it cannot easily isolate inositol in a pure form. It must be used in conjunction with another adsorbing agent that can separate inositol from fructose.

Zeolite Y and the method for its manufacture are described in detail in United States Patent No.².

130 007, issued April 21, 1954 to DW Breck. Zeolite X and the method for its manufacture are described in detail in United States Patent No.². No. 2,882,244, issued April 14, 1959 to RM Milton. The disclosures of both of these patents are incorporated herein by reference.

Type X and Type Y zeolites useful in accordance with the present invention are those whose zeolitic cations are predominantly sodium, barium or calcium; that is, these zeolites may contain a minimum amount of another cation, provided that the zeolite is capable of effecting the desired separation. For example, calcium or zeolite-exchanged zeolites. Barium may be prepared from sodium-exchanged zeolite using known techniques and the product may contain a small amount of sodium and still be useful in accordance with the present invention. Similarly, other cations such as potassium may be added to zeolites in small amounts or present as impurities without adversely affecting the utility of these zeolites in the present invention. More specifically, it is preferred that at least about 50%, and more preferably than about 70 on an equivalent load basis, of the A10 tetrahedrons._iLof type X or type Y zeolite are electrovalently satisfied with the specified cation.

The adsorption affinities of the various zeolites for the different carbohydrates were determined by an impulse assay. This assay consisted of filling a column with the appropriate zeolite, placing it on a heater block to maintain constant temperature and eluting solutions through the column with water to determine the solute retention volume. Solute retention volume is defined as the elution volume minus the void volume. 0 void volume is the volume of solvent required to elute a non-adsorbent solute through the column. To determine void volume, a soluble fructose and inulin polymer which was too large to be adsorbed within the pores of the zeolite was chosen as a solute. The volume of inulin elution was first determined. Elution volumes of the five carbohydrates identified above were then determined under similar experimental conditions. Retention volumes were calculated and are pooled in Table I. From the retention volume data, the following separation factors (SF) were calculated.

Inositol

Ϋ (ie SPj- ^ q),

Glucose

Inositol (ie SF_{I / Sa}) and

Sucrose according to the following equation

Inositol (iSto is, SF-jyg),

Fructose

Inositol (ie SF_{I / Sq})

Typical Sorbitol:

SP

I / &amp;

Inositol

Glucose

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retention volume for inositol peak retention volume for glucose peak

A factor SFj / q greater than unit indicates that the particular adsorbing agent was selective for glucos inositol and, similarly, for the other separation factors listed in Table II. Separation factor values ​​calculated according to the above method are shown in Table II.

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<img file="PT77337B_D0010.tif" />

By a similar technique, retention volumes and separation factors for inositol and various carbohydrates were obtained using a NaX zeolite (SiC4 / AlgO2 molar portion equal to 2.5) and the results obtained find are gathered in the following Table III:

TABEDA III

Fixed Retention Volumes and NaX Separation Factors

Column Dimensions: 40cm x 7.6mm Inner Diameter (15.75 inches x 0.30 inches)

Flow velocity; 2.2 cm per minute (0.53 gpm / ft) Temperature: 71.1 ° (160 ° P)

Pore ​​of zeolite: powder

<td>Carbohydrate</td><td>Corrected retention volume (in ml)</td><td>Inositol of Carbohydrate</td>

<td>Inulin</td><td> 0,0</td><td> -</td>

<td>L-Arabinose</td><td> 2,0</td><td> 4,4</td>

<td>D-Galactose</td><td> 1,0</td><td> 8,7</td>

<td>D-Mannose</td><td> 1,5</td><td> 5,8</td>

<td>D-Ribose</td><td>0</td><td> &gt;43,0</td>

<td>D-Xylose</td><td> 1,0</td><td> 8,7</td>

<td>D-Cellobiose</td><td> 0^0</td><td> &gt;43,0</td>

<td>D-Rafinose</td><td> 1,2</td><td> 7,3</td>

<td>D-Xylitol</td><td> 2,2</td><td> 4,0</td>

<td>Inositol</td><td> 8,7</td><td> 1,0</td>

In order to separate inositol and / or sorhitol from other carbohydrates into solutions by the process according to the present invention, preferably a solid zeolite adsorbent bed is loaded with adsorbed products, the unabsorbed mixture is removed or The adsorbed bed is adsorbed and the inositol and / or sorbitol adsorbed by the adsorbent zeolite is desorbed by means of a desorbent. 0 ? ?^:·./ •OK.

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<img file="PT77337B_D0011.tif" />

<img file="PT77337B_D0012.tif" />

The adsorbing agent may, if desired, be contained in a single bed, in a plurality of beds using conventional oscillating bed operation techniques or in a type of countercurrent simulated moving bed apparatus depending on the zeolite and which of the two. inositol and / or sorbitol is adsorbing. Thus, a chromatographic elution method (such as described in United States Patent No.^s. 3,928,193, the specification of which is incorporated herein by reference) to recover each of the five carbohydrates identified above in pure form, including inositol. As adsorbent zeolite, BaY, NaX and CaX can be used. CaX cannot be used alone as inositol / fructose separation must be by means of a second bed which may contain any of CaX, NaX, BaX or BaY.

Based on the data in Tables I and II, it is generally preferred that the 3 sodium forms of zeolites X and Y have a smaller silica to alumina ratio as such zeolites generally allow greater separation factors to be achieved.

A preferable method for carrying out the process according to the present invention in practice is chromatographic column separation. In this method, feed solution is injected briefly into the top of a column and eluted down through the column with water. As the mixture passes through the column, chromatographic separation gives rise to an increasingly enriched zone in the adsorbed carbohydrate. The degree of separation increases as the mixture passes further down the column to the desired degree of separation. At this time, the column effluent may first be diverted to a container collecting a pure product. Then, during the time that there is a carbohydrate mixture coming out of the column, the effluent may be directed to a mixed product container. Then, when the adsorbed carbohydrate zone emerges from the end of the column, the effluent may be directed to a container for that product.

Once the chromatographic bands have passed a sufficient distance through the column, a new charge is introduced at the entrance of the column and the entire cycle is repeated.

<img file="PT77337B_D0013.tif" />

the process. The mixture exiting the end of the column between moments of appearance of pure fractions is recycled back to the feed and passed back through the column until extinction.

The degree of separation of the peaks as they pass through this chromatographic column will increase as the column length increases. Therefore, a column of sufficient length can be designed to achieve any desired degree of separation of the two components from each other.

Accordingly, it is also possible to operate such a process so that it does not essentially involve the recirculation of an undivided mixture backward to the feed. However, if high purity is required, such a high degree of separation may require an exceptionally long column. In addition, as components are eluted through the column, their average concentrations gradually decline. In case carbohydrates are eluted with water, this means that product streams will be increasingly diluted with water. Therefore, it is very likely that an optimal process (to achieve high purity of components will include the use of a much shorter column (than would be necessary for complete peak separation) and also involve separation of the effluent portion. which contains the mixture of peaks and their recirculation for food as mentioned above.

It is also possible to use NaX, BaX and BaY in a simulated moving bed process (for example, as described in United States Patent No. 2,985,589, the specification of which is incorporated herein by reference). However, it is impossible to use CaX or CaY alone in a one-stage simulated moving bed process to produce inositol when sorbitol is also present because for such a process only the least intensely adsorbed adsorbent can be obtained in pure form. the most strongly adsorbed. However, it is possible to design a two stage process using, for example, CaX on the first floor to separate (inositol + sorbitol) into a fraction of (sucrose + fructose + glucose) and then use CaY on the second floor to separate inositol. of sorbitol.

In the operation of a simulated moving bed technique

<img file="PT77337B_D0014.tif" />

The choice of a desorbent agent or fluid (solvent) must take into account the need for it to be able to easily displace the adsorbed carbohydrate from the adsorbent bed and also that the carbohydrate in the feed mixture is capable of displacing it. the adsorbed desorption agent from a prior adsorption stage. In addition, the desorption agent employed should be easily separable from the mixture with the carbohydrate components of the feed. Therefore, it is envisaged to use a desorbing agent which has characteristics that allow it to be easily fractionated from the carbohydrate. For example, desorbing agents such as alcohols, ketones, water, mixtures thereof, mixtures of alcohols and water, particularly methanol and ethanol, etc. should be used. The preferred desorbing agent is water.

BaX and BaY are very strong adsorbents for inositol, which makes them particularly suitable for use in inositol recovery where inositol is a relatively sparse component in the mixture and its concentration is low. This strong affinity means a high adsorption capacity even at low concentrations. However, intense affinity also means a broad front of desorption. In this case, it may be very economically convenient to use a fixed bed adsorption / desorption process. In this type of process, the feed is allowed to flow through the bed until most of the bed is saturated with inositol. Then the bed is unsorbed. The effluent fraction containing pure inositol is collected and the fraction containing contaminated inositol recirculated.

Several modifications of this process are possible which will be obvious to those skilled in the art. For example, after loading the bed of BaX or BaY to near the point where inositol begins to break bonds and appear in the effluent, the feed may become a co-current of pure inositol in water, which may be It is passed through the bed to displace the adsorbent inositol components and the voids in the bed. When these components other than inositol have been properly displaced from the bed, it may be counter-absorbed with water to recover adsorbent inositol.

<img file="PT77337B_D0015.tif" />

and the voids. This type of co-product bed loading / countercurrent purge / counter-current desorption can be particularly interesting when inositol is present in low concentrations and is to be recovered at higher levels of purity.

NaX is also a particularly suitable adsorbent for inositol recovery because of its unusually high selectivity over inositol. Although its adsorption capacity is not as high as. BaX and BaY, NaX inositol desorption is faster than BaX and BaY. Thus, NaX can be used for a separation process that has a shorter cycle time than BaX and BaY and is suitable for both fixed bed and simulated moving bed processes.

Although it is possible to use activated zeolite crystals in a non-agglomerated form, it is generally more feasible, particularly when the process involves the use of a fixed adsorption bed, to agglomerate the crystals into larger particles to reduce the loss of moisture. system load. 0 The particular binding agent and the manner of proceeding employed in the agglomeration are not critical factors but it is important that the binding agent be as inert as possible with respect to the carbohydrates being adsorbed and the desorption agent. The ratios of zeolite to binder are advantageously within the range of 4 to 20 parts of zeolite per binder on an anhydrous weight basis.

The temperature at which the process adsorption operation should be performed should be between 0 and 150 ° C.^andC. As the temperature rises, the temperature at which the desorbing agent boils is reached. Preferably, the adsorption operation should be carried out at a temperature of about 15 ° C.²0 and about 100^andC. Pressure conditions must be maintained to maintain the system in liquid phase. High process temperatures unnecessarily necessitate the use of high pressure apparatus and increase the cost of the process.

Another method for carrying out the process according to the present invention in practice is shown in the drawing of Figure 5. In this method, a number of fixed beds are limited.

<img file="PT77337B_D0016.tif" />

<img file="PT77337B_D0017.tif" />

connected to each other by ducts that are connected to a special valve (for example, of the type described in United States Patent No.^The. 2,985,589). The valve sequentially moves the liquid feed and product extraction points to different positions around an arrangement of the individual fixed beds such that the countercurrent movement of the adsorbent is simulated. This process is appropriate for binary separations.

In the drawings, Pigura 5 represents a hypothetical moving bed countercurrent flow diagram involved in the practical embodiment of a typical embodiment of the process according to the present invention. Referring to the drawing, it is understood that while the liquid current inputs and outputs are represented as being fixed and the adsorbent mass is represented as moving in countercurrent relationship with the feed and the desorbent material, this representation is intended primarily make it easier to describe how the system works. In practice, the adsorbent mass is generally in a fixed bed with the liquid stream inlets and outlets moving relative to each other. Accordingly, a feed material is introduced into the system through the tubing 10 to the adsorbent bed 12 which contains adsorbent zeolite particles transiting down therethrough. The temperature is equal to 70²0 throughout the system and the pressure is substantially atmospheric pressure. 0 The feed component or components are preferably adsorbed onto the zeolite particles moving through the bed 12 and the refined is entrained by the liquid water stream acting as a desorbent exiting the bed 12 through the tubing 14 and its largest. The part is extracted through the pipe 16 and fed to the evaporator 18 in which the mixture is fractionated and the refined concentrate is discharged through the pipe 20. Water acting as a desorbent exits from the evaporator 18 through the tubing 22 and is fed to the tubing 24 through which it is mixed with additional desorbent which exits the adsorbent bed 26 and is recirculated to the bottom of the adsorbent bed 30. The zeolite having the adsorbed carbohydrates passes down through the tubing 44 to the bed 30 where it is countercurrently contacted with the recycled desorbent which effectively desorbs the hi (/

<img file="PT77337B_D0018.tif" />

carbonate before the adsorbent passes through the bed 30 and enters the tubing 32 through which it is recreated to the top of the adsorbent bed 26. The desorbent and the deadsorbed carbohydrate exits the bed 30 through the tubing 34. A portion of this liquid mixture is diverted through the tubing 36 through which the evaporator 38 passes and the remainder passes upwards through the adsorbent bed 12 for further treatment as described hereinbefore. In evaporation device 38, the desorbent and carbohydrate are fractionated and the produced carbohydrate is recovered via tubing 40 and the desorbent is either discarded or passed through tubing 42 to tubing 24 to recirculation as described above. The non-bypassed portion of the desorbent / refined mixture passes from bed 12 through tubing 14, enters bed 26 and moves upwardly countercurrent with the adsorbent agent constituted by the charged zeolite / desorbent agent passing down through from the recycling pipe 32. 0 The desorbent agent passes from bed 26 in relatively pure form through recirculation tubing 24 and to bed 30 as described hereinbefore.

The following Examples are presented to illustrate the present invention. However, they do not limit the present invention to the embodiments mentioned in the Examples. All examples are based on actual experimental work. In the following Examples, the following abbreviations and symbols having the following meanings are used;

NaX = sodium exchange zeolite X

NaY = sodium exchange zeolite Y

BaX = barium exchanged zeolite X p

gpm / ft = gallons per minute per square meter

<img file="PT77337B_D0019.tif" />

Example 1

A 40 cm (15.75 inch) column with an internal diameter of 7.6 mm (0.3 inch) was filled with powdered NaY zeolite (SiOg / AlgO 4 molar ratio = 5.0). It was then filled with water and kept at a temperature of 71.1^The0 Water was then pumped through the column and a passage rate of 2.2 æm per minute (0.53 gpm / ft) was maintained. Over a period of time, the feed was switched on to a mixture containing 3.9 µg glucose, 3.7 µg fructose, 0.6 µg saoarose, 1.0 µg sorbitol and 0.8 µg inositol and then it went back to water. The column effluent composition was controlled with a refractive index detector. A refractive index detector cannot differentiate one carbohydrate from another but detects the presence of carbohydrate in the effluent. These detectors are most useful when each component emerges into the effluent as a completely separate peak. The identity of each peak can then be determined by its characteristic retention volume. However, such detection techniques may also be useful to show that there is a lack of separation power in a column or under certain conditions. In such circumstances, the mixture will come out with a single peak with a small width. Figure 1 of the drawings represents the elution curve for the above five-component mixture that emerged from the NaY-containing column as a single peak. 0 The single observed peak indicates that the separation capacity of this NaY zeolite was insufficient under the above conditions to allow resolution of inositol or other components and to obtain separate peaks. However, based on the data in Table I above, it is evident that this single peak is the sum of separate peaks attributable to each component. In addition, those skilled in the art understand that using different conditions (e.g., a larger column, lower flow rate, thinner zeolite foot, different feed such as without fructose, different detector, etc.) can be obtained. An observable separation is achieved using this NaY zeolite (compare with the results obtained in Example 4, infra, where NaX separated inositol with a completely separated pod under similar experimental conditions).

<img file="PT77337B_D0020.tif" />

Example 2

The same column and the same experimental conditions were used as in Example 1, except that Bax zeolite powder (Si0 molar ratio) was used.₂/ AlgO = 2.5). Figure 2 represents the elution curves. The order of elution is sucrose, glucose, fructose, sorbitol and inositol. Inositol is well separated from all other carbohydrates.

Example 3

A 160 cm (63 inch) column with an internal diameter of 7.6 mm (0.3 inch) was loaded with BaX zeolite (Si0 molar ratio₂ / AlgO ^ = 2.5) (particles 30 x 40 meshes) and remained at 71.1^sC. The column was loaded with a feed containing 15.6% glucose, 14% fruitBe, 2.4% sucrose, 4.0% sorbitol and 3.2% inoaitol. After the spine reached equilibrium, regeneration began. Water was used as a desorbent and pumped through the column at a flow rate of 1.03 liters per minute (0.27 gallon per minute). The effluent was collected and analyzed by liquid chromatography. The results obtained are shown in Figure 3. 80 ciP of pure inositol was collected with an average concentration of 1% by weight.

The same column as in Example 3 was loaded with zeolite NaX (molar ratio SiO₂ / Al₂O = 2.5) (30 x 40 mesh particles) and held at 71.1 ° C (1660 ° F). The column was subjected to the same operative mode as described in Example 1. Figure 4 represents the elution curves. Sorbitol, sucrose, glucose and fructose emerge as a peak. Inositol emerges as the second peak, well separated from the first.