A class of pillared interlayered clay molecular sieve products with regularly interstratified mineral structure.

This invention relates to pillared interlayered clay molecular sieve (PICMS) products and methods of their preparation. These products can be used as hydrocarbon conversion catalysts, absorbents and catalyst carriers. More particularly, the present invention relates to cross-linked regularly interstratified mineral clay (RIMC) products and methods of their preparation.

Until now, prior PICMS products were all cross-linked smectites type molecular sieve products prepared from smectites clays. PICMS products prepared from clays other than smectites have never been reported in the literature.

The smetites is a type of single layer mineral clay which is represented by the general formula: <chemistry id="chem0001" num="0001"><img file="EP0197012A2_D0001.tif" /></chemistry>The smectites clay group includes motmorillonite, bentonite, beidellite, hectorite, vermiculite and the like. Their characteristic designation is basal spacing (d₀₀₁) 0 of 9-15 A for air drier samples.

The cross-linked smectites type PICMS products are prepared by insertion of organic cross-linking agent or inorganic polyreric cationic hydroxy metal complexes into ever the improvement is not good enough as the resulting product can only withstand treatment at 676°C with 5 psi steam for 8 hours.

So far, the thermal and hydrothermal stabilities of the PICMS product prepared by smectite clays is still an open question. Sample treated at 730°C with steam for 4 hours, 90 per cent of its surface area and 80 per cent of its pore volumes were lost. Its microactivities drop sharp ly from 80 per cent to 30 per cent (Occelli, M.L., I &amp; E. C. Prod. Res. &amp; Dev., 22, 553, 1983).

All the data mentioned above have clearly indicated that the prior PICMS product is not as good as REY type zeolite catalysts with respect to high temperature stability in order to be used in catalytic cracking process. Hence no cracking catalysts from cross-linked smectites type PICMS products was ever used in commercial scale.

An object of the present invention is to develop another class of catalytic materials other than smectites and thereby to prepare a class of new PICMS with large pore size and excellent hydrothermal stability so as to improve the deficiency of prior PICMS of cross-linked smectites. Another object of the present invention is to provide the method of preparation and the application of said new PICMS.

The present invention provides a class of PICMS products with RIMC structure, such as cross-linked rectorites, mica/smectites, illite/smectites, glauconite/smectites, chlorite/smectites, vermiculite/smectites, kaolinite/ structure of RIMC used by the present invention.' <ul id="ul0001" list-style="none"><li>- Fig. 2 is a cross-sectional view of the structure of the PICMS products provided by the present invention.</li><li>- Fig. 3 shows X-ray powder diffraction patterns (001) of cross-linked rectorites and cross-linked smectites after thermal treatment at different temperatures.</li><li>- Fig. 4 shows the microactivity curves of the PICMS of cross-linked rectorites, PICMS of cross-linked smectites, amorphous silica-alumina catalysts containing 13 per cent alumina and commercial REY zeolite cracking catalysts after hydrothermal treatment with 100 per cent steam at atmospheric pressure and various temperatures.</li></ul>

The present invention provides a class of PICMS made from the catalytic materials with the structure of RIMC such as cross-linked rectorites, -mica/smectites, -illite/ smectites, -glauconite/smectites, -chlorite/smectites, -vermiculite/smectites, ,kaolinite/smectites.

The PICMS products comprises the unit layers which is actually the non-swelling component in the RIMC, the pillars made of inorganic oxides inserted into the interlayers of the swelling components in the RIMC structure, and the micropores formed by the unit layers and the pillars.

The RIMC consist of swelling and non-swelling components arranged in a manner that alternatively shareing a 2:1 clay layer which formed a regularly crystalline structure. It retains not only the characters of swelling single layer mineral clays, so that enables pillared interlayers could be formed, but also because of the existence free) are represented as follows: <chemistry id="chem0002" num="0002"><img file="EP0197012A2_D0002.tif" /></chemistry>

The main character of the rectorites are narrated as follows: <ul id="ul0002" list-style="none"><li>1. The rectorite structure contains a swelling clay component part. On its 2:1 clay layers there are isomorphous substitutions. In its interlayer zones there are exchangeable cations. The swelling clay component part can be propped to form large micropores under substitution of cross-linked agent e.g. polymeric cationic hydroxy metal (Al or Zr) complex for exchangeable cations.</li><li>2. The 2:1 clay layers are shared by mica and smectites components in the rectorite structure.Thereof isomorphous substitutions occur on the tetrahedral silica-oxygen sheet in the 2:1 clay layers so as to form stable ionic bonds between exchangeable cations and the ions which are deficient in the positive charges on the 2:1 clay layers. Thus it is advantageous to form the stable connections of clay layers and the pillars.</li><li>3. The structure of the rectorites clay layers are stable under a temperature as high as 800°C for 17 hours.</li></ul>

The present invention has found that the PICMS products prepared from RIMC with the characteristics of above said mineral clays have extraordinary thermal and hydrothermal Noorgan. Khim., 8(7), 1923 (1963).

The PICMS of present invention were prepared by cross-linking the clay slurry of the RIMC mentioned above with the solution of the polymeric cationic hydroxy metal complex mentioned above. The following general procedure may be used: <ul id="ul0003" list-style="none"><li>(a). The preparation of mineral clay slurry: the purified naturally occurring Ca-form mineral clay was changed into that of Na-, NH₄- or RE-form by ion-exchange method and thereby the clay slurry with a solid content of less than 5% (wt.) and a particle size of smaller than 2 p is obtained.</li><li>(b). The preparation of the solution of polymeric cation ic hydroxy metal complex (cross-linking reagent): the polymer was diluted with deionized H₂0 so as to obtain the aqueous solution of polymeric cationic hydroxy metal complex with a concentration of 10-1000, preferably 30-500 milligram-atom aluminum per litre or 5-100, preferably 10-50 milligram-atom zirconium per litre.</li><li>(c). The cross-linking reaction: the mineral clay slurry prepared as mentioned above was added to cross-linking reagent at a ratio of 1.5-5.0 milligram-atom aluminum or 2.0-5.0 milligram-atom zirconium per gram clay (dry basis). The reaction proceeds under stirring at the temperature ranging from room temperature to 100°C for more than 5 minutes.</li></ul>During the reaction the pH of said mixture is adjusted with NH₄0H and kept within the range of 4-6. <ul id="ul0004" list-style="none"><li>(d). Ageing: the resulting product was stilled and aged, with a pH of 4-6 at the temperature ranging from room temperature to 75°C for O-24 hours.</li></ul>a (001) basal spacing of 27.0-31.0 A, an interlayer distance of 6.0-10.0 A, and have greater than 50% of its 0 pore volume in pores of less than 50.0 A in radius.

The PICMS of present invention have the characteristics of a microporous structure and a solid acid sites, and are suitable for catalysts, used in carbonium-ion reactions, adsorbents and carriers. More particularly, the PICMS cross-linked rectorites in present invention and the products thereof possess not only the characteristics mentioned above but also have extraordinary thermal and hydrothermal stability which are far superior to that of the prior PICMS of cross-linked smectites type and also better than that of some commercial REY-type zeolite catalysts. After hydrothermal treatment at 800°C under atmospheric pressure with 100% steam for 17 hours, said PICMS remain essentially the constant structure and the constant interlayer distance. It retains a surface area of 70%, MAT conversion of 90%. Furthermore, the PICMS of cross-linked rectorites in present invention are beneficial to crack heavy feedstocks and are especially suitable for preparation of cracking catalysts for petroleum processing.

The PICMS of present invention may be combined with other inorganic oxide adsorbents and catalysts such as silica, alumina, silica-magnesia, silica-alumina hydrogel or hydrosol, and natural or synthetic zeolites, and clays. Said PICMS are particularly useful in the preparation of catalysts which contain active/stabiliz- ing metals such as platinum, palladium, cobalt, molybdenum, nickel, tungsten, rare-earths and so forth, as Then the resulting mixture was aged for 24 hours at room temperature. The pH was maintained at 4-6, filtered, washed to be free of Cl , dried at 110°C, calcined in air for 2 hours at 650°C, thereby the PICMS with Al₂0₃ pillars of cross-linked rectorites type were obtained.

The structure characteristics of said molecular sieves measured by conventional X-ray powder diffraction method are as follows: they possess a layer thickness of 20.0- 21.0 A, a (001) basal spacing of 27.0-31.0 A with various water content, and an interlayer distance of 6.0-10.0 A. The major components of said molecular sieves measured by standard chemical analysis is listed in Table 1. The surface areas, pore volumes and distribution of said molecular sieves measured by BET low temperature N₂ adsorption method are listed in Table 2. <tables id="tabl0001" num="0001"><img file="EP0197012A2_D0003.tif" /></tables><tables id="tabl0002" num="0002"><img file="EP0197012A2_D0004.tif" /></tables>these four samples after hydrothermally treated with 100% steam under 1 atm. at various temperatures for light diesel feedstock. The evaluation test was carried out in a MAT unit. The evaluation conditions were as follows: reactant: Dagang light diesel oil (235-337°C), reaction temperature: 460°C, contact time: 70 seconds, WHSV: 16 hr^-1, catalyst-to-oil ratio: 3.2, sample used: 5 g. In Fig. 4, curve 1,2,3 and 4 represent respectively the decline in activities of the PICMS of cross-linked rectorites, the PICMS of cross-linked smectites, amorphous silica-alumina cracking catalysts and commercial REY-type zeolite cracking catalysts.

Figure 4 shows that the microactivity of the PICMS of cross-linked rectorites retains a value of 46%, while that of the commercial REY-type zeolite cracking catalysts declines to a value of 23% after the hydrothermal treatment at 800°C with 100% steam for 28 hours. Furthermore, the microactivity of the PICMS of cross-linked smectites and amorphous silica-alumina cracking catalysts have dropped sharply to values of 12% and 20% respectively after the hydrothermal treatment at 800°C with 100% steam for 4 hours.

EXAMPLE 4

The PICMS of cross-linked rectorite type prepared by the method in Example 1 is capable to resist contaminations of heavy metals.

The conventional REY-type zeolite and the PICMS of cross-linked rectorites were impregnated respectively with NH₄V0₃ aqueous solution at the ratio (wt./wt.) of 1: <tables id="tabl0003" num="0003"><img file="EP0197012A2_D0005.tif" /></tables>

EXAMPLE 5

The cracking catalyst with an active component of PICMS of cross-linked rectorites has higher reactivity in crack ing heavy distillate than the commercial REY-type zeolite cracking catalyst.

The mixture of the Na- form rectorite clay slurry prepared in Example 1 and Suzhou machine-selected 2 # halloy- site was slurried at a weight ratio of 1:1 (dry basis). After perfectly mixing by stirring the cross-linking reaction was proceeded in the way of Example 1 (the used weight of cross-linking reagent was based on the weight of rectorite), then aged, filtered, washed, spray dried, calcined by the method in Example 1, thereby the microspheric cracking catalyst containing the PICMS of cross-linked rectorites was obtained.

The cracking activities for light diesel feedstock and heavy distillate of the commercial REY-type zeolite

EXAMPLE 6

The cracking catalyst containing the PICMS of cross-link ed rectorites prepared by the method in Example 5 demonstrate similar selectivity in cracking a feedstock of mixed distillate-residue to that of the commercial REY-type zeolite cracking catalyst.

The selectivities of the commercial REY-type zeolite cracking catalyst and the cracking catalyst containing the PICMS of cross-linked rectorites after the hydrothermal treatment at 800°C with 100% steam under 1 atm for 10 hours were evaluated respectively in a pilot fixed bed reactor. The evaluation conditions were as follows: reactant: mixture of 40% (wt.) Da-Gang 330-520°C distillate with 60% (wt) Sheng-Li atmospheric residue therein the Conradson carbon residue content is 6.85% (wt), reaction temperature: 500°C, reaction period: 230 seconds, WHSV: 10 hr ¹, catalyst-to-oil ratio: 1.6, catalyst used: 20 g. The data are listed in Table 5. the conventional amorphous silica-alumina catalyst for the oligomerization are 30% and 20% respectively.

EXAMPLE 8 -

The PICMS of cross-linked mica-montmorillonites type were prepared from mica-montmorillonite by the method in Example 1. The structure characteristics of said molecular sieves measured by conventional X-ray powder diffraction method are as follows: they possess a layer thickness of 20.0-21.0 A, a (001) basal spacing of 29.5 A ( a basal spacing of 24.5 A before cross-linking), and an inter- layer distance of 7.5-8.5 A. After the thermal treatment at 800°C for 4 hours the (001) basal spacing decreased only slightly to 27.3 A. Thereby it is concluded that said molecular sieves have good thermal stability.

EXAMPLE 9

The PICMS of cross-linked chlorite-smectites type were prepared from chlorite-smectite by the method in Example 1. The structure characteristics of said molecular sieves measured by conventional X-ray powder diffraction method are as follows:they possess a layer thickness 0 0 of 23.0-24.0 A, a (001) basal spacing of 32.0 A (a basal spacing of 28.0 A before cross-linking), and an inter- layer distance of 8.0-10.0 A.

EXAMPLE 10

The polymerized zirconium chlorohydroxide cross-linking reagent was prepared by polymerizing 0.33 mole ZrOCl₂ in itself with refluxing under 1 atm at boiling temperature for 20.5 hours, then 120 ml of this polymer was taken out and diluted with 1530 ml of deionized H₂0. Na₂0 ratio of 3.0 was diluted to 100 ml with deionized H₂0. A diluted chlorhydric acid solution obtained by diluting 1 ml of 37% HC1 to 100 ml with deionized H 0 was added to the diluted Na₂SiO₃ sol mentioned above, thereby a silicon sol with a pH of 3-5 was obtained. <ul id="ul0005" list-style="none"><li>(3) The preparation of the solution of cross-linking reagent: the clear and colorless solution of aluminium cross-linking reagent containing silicon was obtained by mixing aluminium polymers with silicon hydrosol prepared above, adjusting the pH of said mixture with 3% NH₄0H and keeping within the range of 4-6, then ageing at room temperature for 24 hours.</li><li>(4) The preparation of molecular sieves: 873.4 g of the rectorite clay slurry prepared in Example 1 was added to the solution of aluminium cross-linking reagent containing silicon prepared above. The mixture was reacted, aged, filtered, washed, dried and calcined in the way of that in Example 1 and thereby the PICMS with SiO₂-Al₂O₃ pillars of cross-linked rectorites type were obtained. 0</li></ul>

A(001) basal spacing of 27.0-30.0 A was measured by conventional X-ray powder diffraction method. By the evaluation method in Example 3, the initial microactivity (MAT) was 61% (wt) and decreased to 40% (wt) after the hydrothermal treatment at 800°C with 100% steam under 1 atm for 17 hours.

EXAMPLE 12

The PICMS of present invention can be also prepared by using polymerized aluminium chlorohydroxide containing boron as the cross-linking reagent.