SYNTHETIC POROUS CRYSTALLINE MCM-58. ITS SYNTHESIS AND USE This invention relates to a novel synthetic porous crystalline material, referred to herein as MCM-58, to a method for its preparation and to its use in catalytic conversion of organic compounds. Zeolitic materials, both natural and synthetic, have been demonstrated in the past to have catalytic properties for various types of hydrocarbon conversion. Certain zeolitic materials are ordered, porous crystalline aluminosilicates having a definite crystalline structure as determined by X-ray diffraction, within which there are a large number of smaller cavities which may be interconnected by a number of still smaller channels or pores. These cavities and pores are uniform in size within a specific zeolitic material. Since the dimensions of these pores are such as to accept for adsorption molecules of certain dimensions while rejecting those of larger dimensions, these materials have come to be known as "molecular sieves" and are utilized in a variety of ways to take advantage of these properties. Such molecular sieves, both natural and synthetic, include a wide variety of positive ion-containing crystalline silicates. These silicates can be described as a rigid three-dimensional framework of Si0 ₄ and Periodic Table Group IIIA element oxide, e.g., A10 ₄ , in which the tetrahedra are cross-linked by the sharing of oxygen atoms whereby the ratio of the total Group IIIA element, e.g., aluminum, and silicon atoms to oxygen atoms is 1:2. The electrovalence of the tetrahedra containing the Group IIIA element, e.g., aluminum, is balanced by the inclusion in the crystal of a cation, for example an alkali metal or an alkaline earth metal cation. This can be expressed wherein the ratio of the Group IIIA element, e.g., aluminum, to the number of various cations, such as Ca/2, Sr/2, Na, K or Li, is equal to unity. On _* - type of cation may be exchanged either entirely or partially with another type of cation

utilizing ion exchange techniques in a conventional manner. By means of such cation exchange, it has been possible to vary the properties of a given silicate by suitable selection of the cation. The spaces between the tetrahedra are occupied by molecules of water prior to dehydration.

Prior art techniques have resulted in the formation of a great variety of synthetic zeolites. Many of these zeolites have come to be designated by letter or other convenient symbols, as illustrated by zeolite A (U.S. Patent 2,882,243); zeolite X (U.S. Patent 2,882,244); zeolite Y (U.S. Patent 3,130,007); zeolite ZK-5 (U.S. Patent 3,247,195); zeolite ZK-4 (U.S. Patent 3,314,752); zeolite ZSM-5 (U.S. Patent 3,702,886); zeolite ZSM-11 (U.S. Patent 3,709,979); zeolite ZSM-12 (U.S. Patent 3,832,449), zeolite ZSM-20 (U.S. Patent 3,972,983); ZSM-35 (U.S. Patent 4,016,245); zeolite ZSM-23 (U.S. Patent 4,076,842); zeolite MCM-22 (U.S. Patent 4,954,325); and zeolite MCM-35 (U.S. Patent 4,981,663) .

The SiO- _j /Al- _j O- ratio of a given zeolite is often variable. For example, zeolite X can be synthesized with SiO /Al-0 ratios of from 2 to 3; zeolite Y, from 3 to about 6. In some zeolites, the upper limit of the SiO_/Al _? 0 ratio is unbounded. ZSM-5 is one such example wherein the SiO_/Al ₂ <0_ ratio is at least 5 and up to the limits of present analytical measurement techniques. U.S. Patent 3,941,871 (Re. 29,948) discloses a porous crystalline silicate made from a reaction mixture containing no deliberately added alumina in the recipe and exhibiting the X-ray diffraction pattern characteristic of ZSM-5. U.S. Patents 4,061,724, 4,073,865 and 4,104,294 describe crystalline silicate of varying alumina and metal content.

In one aspect, the present invention is directed to a novel synthetic porous crystalline material, named MCM-58, having an X-ray diffraction pattern including the lines listed in Table I below:

In a further aspect, the invention resides in a process for synthesizing MCM-58 which comprises the steps of (i) preparing a mixture comprising sources of alkali or alkaline earth metal (M) , an oxide of trivalent element (X) , an oxide of tetravalent element (Y) , water, and directing agent (R) comprising benzylquinuclidinium cations, and having a composition, in terms of mole ratios, within the following ranges:

Y0 ₂ /X ₂ 0 ₃ 15 to 1000

H ₂ 0/Y0 ₂ 5 to 200

OH~/YC> ₂ 0 to 3 M/Y0 ₂ 0 to 3

R/YO- 0.02 to 1.0

(ii) maintaining said mixture under crystallization conditions including a temperature of 80°C to 250°C until crystals of said material are formed; and (iii) recovering said crystalline material from step (ii) . In yet a further aspect, the invention resides in the use of MCM-58 as a catalyst in the conversion of organic compounds.

In its as-synthesized form, the crystalline MCM-58 material of the invention appears to be a single crystalline phase. It can be prepared in essentially pure form with little or no detectable impurity crystal phases and has an X-ray diffraction pattern which is distinguished from the patterns of other known as-synthesized or thermally treated crystalline materials by the lines listed in Table I below:

TABLE I Interplanar d-Spacincr (A) Relative Intensity, I/Io x 100 10.89 + 0.30 Ξ-VΞ

9.19 ± 0.30 vw 6.55 + 0.29 ^' vw-w

5.86 ± 0.28 vw-w

5.57 + 0.27 vw-w

5.43 ± 0.26 vw-w

4.68 + 0.25 vw-m 4.36 + 0.25 w-vs

4.17 + 0.23 vw-m

4.12 ± 0.23 vw-s

3.78 ± 0.20 wv-s

3.61 ± 0.15 vw-w 3.54 ± 0.15 vw

3.44 ± 0.15 vw-m

3.37 ± 0.15 vw-m

3.06 + 0.15 vw-w

2.84 + 0.15 vw 2.72 ± 0.13 vw

2.66 + 0.12 vw

2 . 46 + 0. 12 vw

2 . 17 + 0 . 10 VW

These X-ray diffraction data were collected with a

Scintag diffraction system, equipped with a germanium solid state detector, using copper K-alpha radiation. The diffraction data were recorded by step-scanning at 0.02 degrees of two-theta, where theta is the Bragg angle, and a counting time of 10 seconds for each step. The interplanar spacings, d's, were calculated in Angstrom units (A) , and the relative intensities of the lines, I/Io is one- hundredth of the intensity of the strongest line, above background, were derived with the use of a profile fitting routine (or second derivative algorithm) . The intensities are uncorrected for Lorentz and polarization effects. The relative intensities are given in terms of the symbols vs = very strong (80-100) , s = strong (60-80) , m = medium (40- 60) , w = weak (20-40) , and vw = very weak (0-20) . It should be understood that diffraction data listed for this sample as single lines may consist of multiple overlapping lines which under certain conditions, such as differences in crystallographic changes, may appear as resolved or partially resolved lines. Typically, crystallographic changes can include minor changes in unit cell parameters and/or a change in crystal symmetry, without a change in the structure. These minor effects, including changes in relative intensities, can also occur as a result of differences in cation content, framework composition, nature and degree of pore filling, and thermal and/or hydrothermal history. The crystalline material of this invention has a composition involving the molar relationship:

X ₂ 0 ₃ :(n)Y0 ₂ , wherein X is a trivalent element, such as aluminum, boron, iron, indium, and/or gallium, preferably aluminum; Y is a tetravalent element such as silicon, tin, and/or germanium, preferably silicon; and n is from greater than 10 to 1000,

usually from greater than 10 to 400, more usually from 20 to 200. In the as-synthesized form, the material has a formula, on an anhydrous basis and in terms of moles of oxides per n moles of Y0_, as follows: (0.1-2)M ₂ O: (0.2-2)R:X ₂ O ₃ :nYO ₂ wherein M is an alkali or alkaline earth metal, and R is an organic directing agent. The M and R components are associated with the material as a result of their presence during crystallization, and are easily removed by post- crystallization methods hereinafter more particularly described.

The organic directing agent R for use herein is the cation benzylquinuclidinium, having a formula C U I , and may be represented as follows:

The source of this organic cation may be, for example, the halide, e.g., chloride or bromide, or hydroxide salt. The source of organic directing agent used in the Examples was synthesized by reacting quinuclidine with benzylbromide as follows. A benzylbromide-ethanol mixture was added to a quinuclidine-ethanol mixture at room temperature in a flask equipped with a reflux condenser and stirrer. The reaction mixture was refluxed overnight with stirring and then quenched to -40°C with a dry ice-acetone mixture. The cold product was then filtered and washed with anhydrous diethylether. White crystals of benzylquinuclidinium bromide were recovered.

The crystalline material of the invention is thermally stable and in the calcined form exhibits significant hydrocarbon sorption capacity. To the extent desired, the original sodium and/or potassium cations of the as-synthesized material can be replaced in accordance with techniques well known in the art, at least in part, by ion exchange with other cations. Preferred replacing cations include metal ions, hydrogen ions, hydrogen precursor, e.g., ammonium, ions and mixtures thereof. Particularly preferred cations are those which tailor the catalytic activity for certain hydrocarbon conversion reactions. These include hydrogen, rare earth metals and metals of Groups IIA, IIIA, IVA, IB, IIB, IIIB, IVB and VIII of the Periodic Table of the Elements. Prior to use, the crystalline material of the invention may be subjected to treatment to remove part or all of any organic constituent. This is conveniently effected by thermal treatment at a temperature of at least 370°C for at least 1 minute and generally not longer than 20 hours. While subatmospheric pressure can be employed for the thermal treatment, atmospheric pressure is desired for reasons of convenience. The thermal treatment can be performed at a temperature up to about 925°C. The thermally treated product, especially in its metal, hydrogen and ammonium forms, is particularly useful in the catalysis of certain organic, e.g., hydrocarbon, conversion reactions.

The crystalline material MCM-58 can also be used as a catalyst in intimate combination with a hydrogenating component such as tungsten, vanadium, molybdenum, rhenium, nickel, cobalt, chromium, manganese, or a noble metal such as platinum or palladium where a hydrogenation- dehydrogenation function is to be performed. Such component can be in the composition by way of cocrystallization, exchanged into the composition to the extent a Group IIIA element, e.g., aluminum, is in the

structure, impregnated therein or intimately physically admixed therewith. Such component can be impregnated in or on to it such as, for example, by, in the case of platinum, treating the silicate with a solution containing a platinum metal-containing ion. Thus, suitable platinum compounds for this purpose include chloroplatinic acid, platinous chloride and various compounds containing the platinum amine complex.

The crystalline material of this invention, when employed either as an adsorbent or as a catalyst in an organic compound conversion process should be dehydrated, at least partially. This can be done by heating to a temperature in the range of 200°C to 370°C in an atmosphere such as air, nitrogen, etc. , and at atmospheric, subatmospheric or superatmospheric pressures for between 30 minutes and 48 hours. Dehydration can also be performed at room temperature merely by placing the MCM-58 in a vacuum, but a longer time is required to obtain a sufficient amount of dehydration. The present crystalline material can be prepared from a reaction mixture containing sources of alkali or alkaline earth metal (M) , e.g., sodium and/or potassium, cation, an oxide of trivalent element X, e.g., aluminum and/or boron, an oxide of tetravalent element Y, e.g., silicon, directing agent (R) , and water, said reaction mixture having a composition, in terms of mole ratios of oxides, within the following ranges:

Reactants Useful Preferred

Y0 ₂ /X ₂ 0 ₃ 15 to 1000 25 to 500 H ₂ 0/Y0 ₂ 5 to 200 20 to 100

OH ^" /Y0 ₂ 0 to 3 0.10 to 0.50

M/Y0 ₂ 0 to 3 0.10 to 2

R/YO, 0.02 to 1.0 0.10 to 0.50

In the present synthesis method, the preferred source of Y0 ₂ comprises predominately solid Y0 ₂ , for example at least about 30 wt.% solid Y0 ₂ . Where Y0 ₂ is silica, the use

of a silica source containing at least about 30 wt.% solid silica, e.g., Ultrasil (a precipitated, spray dried silica containing about 90 wt.% silica) or HiSil (a precipitated hydrated Si0 ₂ containing about 87 wt.% silica, about 6 wt.% free H_0 and about 4.5 wt.% bound H_0 of hydration and having a particle size of about 0.02 micron) is preferred for MCM-58 formation from the above mixture. Preferably, therefore, the YO , e.g., silica, source contains at least about 30 wt.% solid YC< , e.g., silica, and more preferably at least about 40 wt.% solid Y0 ₂ , e.g., silica.

Crystallization of the present crystalline material can be carried out at either static or stirred conditions in a suitar e reactor vessel, such as for example, polypropyle.ra jars or teflon lined or stainless steel autoclaves, at a temperature of 80°C to 250°C for a time sufficient for crystallization to occur, normally from 12 hours to 100 days. Thereafter, the crystals are separated from the liquid and recovered.

Synthesis of the new crystals may be facilitated by the presence of at least 0.01 percent, preferably 0.10 percent and still more preferably 1 percent, seed crystals (based on total weight) of crystalline product.

The crystalline material of this invention can be used to catalyze a wide variety of chemical conversion processes including many of present commercial/industrial importance. Examples of chemical conversion processes which are effectively catalyzed by the crystalline material of this invention, by itself or in combination with one or more other catalytically active substances including other crystalline catalysts, include those requiring a catalyst with acid activity. Specific examples include:

(1) toluene disproportionation, with reaction conditions including a temperature of 200°C to 760°C, a pressure of 100 to 6000 kPa (atmospheric to 60 atmospheres), a weight hourly space velocity (WHSV) of 0.1 hr -l to 20 hr-1, and a hydrogen/hydrocarbon mole ratio of

fro 0 (no added hydrogen) to 50, to provide disproportionation product, including p-xylene;

(2) transalkylation of aromatics, in gas or liquid phase, with reaction conditions including a temperature of 100°C to 500°C, a pressure of from 100 to 20000 kPa (1 to 200 atmospheres), and a WHSV of from 1 hr~ to 10,000 hr ^" ;

(3) reaction of paraffins with aromatics to form alkylaromatics and light gases with reaction conditions including a temperature of 260°C to 375°C, a pressure of 100 to 7000 kPa (0 to 1000 psig) , a WHSV of 0.5 hr ^"1 to 10 -1 hr , and a hydrogen/ hydrocarbon mole ratio of from 0 (no added hydrogen) to 10;

(4) paraffin isomerization to provide branched paraffins with reaction conditions including a temperature of 200°C to 315°C, a pressure of 800 to 7000 kPa (100 to 1000 psig), a WHSV of 0.5 hr ^"1 to 10 hr ^"1 , and a hydrogen/hydrocarbon mole ratio of 0.5 to 10; and

(5) alkylation of aromatics with olefins with reaction conditions including a temperature of 200°C to 500"C, a pressure of 0 to 500 psig, a total WHSV of 0.5 hr to 50 hr , a hydrogen/ hydrocarbon mole ratio of from 0 (no added hydrogen) to 10, and an aromatic/olefin mole ratio of 1 to 50.

In the case of many catalysts, it may be desirable to incorporate MCM-58 with another material resistant to the temperatures and other conditions employed in organic conversion processes. Such materials include active and inactive materials and synthetic or naturally occurring zeolites as well as inorganic materials such as clays, silica and/or metal oxides such as alumina. The latter may be either naturally occurring or in the form of gelatinous precipitates or gels including mixtures of silica and metal oxides. Use of a material in conjunction with MCM-58, i.e., combined therewith or present during synthesis of the new crystal, which is active, tends to change the conversion and/or selectivity of the catalyst in certain

organic conversion processes. Inactive materials suitably serve as diluents to control the amount of conversion in a given process so that products can be obtained economically and orderly without employing other means for controlling the rate of reaction. These materials may be incorporated into naturally occurring clays, e.g., bentonite and kaolin, to improve the crush strength of the catalyst under commercial operating conditions. Said materials, i.e., clays, oxides, etc., function as binders for the catalyst. It is desirable to provide a catalyst having good crush strength because in commercial use it is desirable to prevent the catalyst from breaking down into powder-like materials. These clay and/or oxide binders have been employed normally only for the purpose of improving the crush strength of the catalyst.

Naturally occurring clays which can be composited with MCM-58 include the montmorillonite and kaolin family, which families include the subbentonites, and the kaolins commonly known as Dixie, McNamee, Georgia and Florida clays or others in which the main mineral constituent is halloysite, kaolinite, dickite, nacrite, or anauxite. Such clays can be used in the raw state as originally mined or initially subjected to calcination, acid treatment or chemical modification. Binders useful for compositing with MCM-58 also include inorganic oxides, such as silica, zirconia, titania, magnesia, beryllia, alumina, and mixtures thereof.

In addition to the foregoing materials, MCM-58 can be composited with a porous matrix material such as silica- alumina, silica-magnesia, silica-zirconia, silica-thoria, silica-beryllia, silica-titania as well as ternary compositions such as silica-alu ina-thoria, silica-alumina- zirconia silica-alumina-magnesia and silica-magnesia- zirconia. The relative proportions of finely divided MCM-58 and inorganic oxide matrix vary widely, with the MCM-58 content

ranging from 1 to 90 percent by weight and more usually, particularly when the composite is prepared in the form of beads, in the range of 2 to 80 weight percent of the composite. The invention will now be more particularly described with reference to the Examples and the accompanying drawings, in which:

Figure 1 shows the X-ray diffraction pattern of the as-synthesized product of Example 6; Figure 2 shows the 2 , 2-dimethylbutane sorption isotherm for the product of Example 14; and

Figure 3 shows the n-hexane sorption isotherm for the product of Example 14.

In the examples, whenever sorption data are set forth for comparison of sorptive capacities for 2,2- dimethylbutane (2,2-DMB) and n-hexane, they were Equilibrium Adsorption values determined as follows. A weighed sample of the calcined adsorbant was contacted with the desired pure adsorbate vapor in an adsorption chamber, evacuated to less than 1 mm and contacted with 5.3 kPa (40 Torr) of n-hexane or 2,2-DMB vapor, pressures less than the vapor-liquid equilibrium pressure of the respective adsorbate at 30°C for n-hexane and 90°C for 2,2-DMB. The pressure was kept constant (within about + 0.5 mm) by addition of adsorbate vapor controlled by a manostat during the adsorption period, which did not exceed about 8 hours. As adsorbate was adsorbed by the MCM-58, the decrease in pressure caused the manostat to open a valve which admitted more adsorbate vapor to the chamber to restore the above control pressures. Sorption was complete when the pressure change was not sufficient to activate the manostat. The increase in weight was calculated as the adsorption capacity of the sample in mg/g of calcined adsorbant. When Alpha Value is examined, it is noted that the

Alpha Value is an approximate indication of the catalytic

cracking activity of the catalyst compared to a standard catalyst and it gives the relative rate constant (rate of normal hexane conversion per volume of catalyst per unit time) . It is based on the activity of silica-alumina cracking catalyst taken as an Alpha of 1 (Rate Constant = 0.016 sec -1). The Alpha Test is described in U.S. Patent

3,354,078; in the Journal of Catalysis, 4, 527 (1965); 6,

278 (1966) ; and 61, 395 (1980) . The experimental conditions of the test used herein include a constant temperature of 538°C and a variable flow rate as described in detail in the Journal of Catalysis. 61, 395.

EXAMPLES 1-11 Experiments -ere conducted for synthesis of crystalline proά.,;.:t material. In these experiments, A1_(S0.) ₃ • 18H-0 and KOH pellets were dissolved in deionized water. The benzylquinuclidinium bromide prepared above was then dissolved in the solution. Colloidal silica sol (30 wt.% SiO_) was then mixed into the solution. The mixture was stirred for 2 minutes to produce a uniform, fluid hydrogel, having, respectively, the compositions shown in Table II where R is the cation of benzylquinuclidinium bromide.

The hydrogel of each experiment was then transferred to a 300 ml stainless steel autoclave equipped with a stirrer. The autoclave was capped and sealed; and 400 psig of inert gas was introduced into the autoclave. Stirring and heating were started immediately. Crystallizations were carried out at 170°C with stirring.

Crystalline products were recovered, filtered, washed with deionized water, and dried on a filter funnel in an air stream under an infrared lamp. The dried crystalline powder products were then submitted for X-ray diffraction and chemical analysis.

25 0.62 7 MCM-58 + mordenite

H ₂ 0/Si0 ₂ = 40, OH~/Si0 ₂ = 0.30, R/SiC> ₂ = 0.20

The X-ray diffraction data for the as-synthesized products of Examples 6 and 7 are presented in Tables III and IV, respectively. The X-ray diffraction pattern generated by the product of Example 6 is presented in Figure 1.

10

15

20

Δ

30

35

40

45 ^* Peak attributed to unidentified impurity phase

TABLE IV

Interplanar d-Spacinσ (A) I/I„

10.91 73 9.21 6

6.57 16 5.87 5

5.58 5

5.43 12 5.03 2

4.97 ^* < 1 ^*

4.69 27

4.59 4

4.36 100 4.23 7

4.17 28

4.13 58

3.95 ^* 1"

3.77 64 3.70 1

3.61 17

3.55 10

3.44 42

3.37 26 3.33 7

3.30 5

3.29 8

3.26 8

3.22 6 3.18 9

3.12 2

3.07 16

3.00 7

2.934 3 2.889 4

2.845 10

2.816 4

2.790 5

2.716 5 2.661 8

2.607 5

2.561 7

2.536 4

2.513 7 2.464 11

2.173 4

Peak attributed to unidentified impurity phase

Chemical analysis results for the as-synthesized products of Examples 2, 3, 5, 6, 8, 9, and 10 are presented in Table V.

TABLE V

( 2'. R = benzylqui .nucli.di.ni.um cation

There appears to be no clear trend in the alkali metal content per 100 tetrahedra, but there does appear to be approximately 4-6 template cations per 100 tetrahedra in the MCM-58 framework, indicating templating activity for the benzylquinuclidinium cation.

EXAMPLES 12-14 MCM-58 products of Examples 4, 5, and 6 were weighed into quartz boats, then placed into a Heviduty ^® tube furnace and sealed with nitrogen gas flowing through the furnace tube. The heating of the furnace was begun at 2°C/minute from room temperature to 538°C. When the furnace reached the maximum temperature, the flowing gas was switched to air, and the calcination of the zeolite was continued for 15 hours before termination.

The air calcined samples were ammonium exchanged with 1 M NH.N0_ at 80°C for 6 hours. After ammonium exchange, the zeolites were filtered, washed with deionized water, and dried in an air stream on the filter funnel under an infrared heat lamp.

The calcination procedure was repeated on the ammonium-exchanged materials in the tube furnace in the same manner as described above, except this time the samples were held at 538 °C for 8 hours to convert them to HMCM-58. Examples 12, 13, and 14 products were MCM-58 materials from the products of Examples 4, 5, and 6, respectively.

EXAMPLE 15 Samples of the HMCM-58 products of Examples 12, 13, and 14 were tested for acid catalytic activity in the Alpha Test and found to have Alpha Values of 521, 164, and 510, respectively.

EXAMPLE 16 The Constraint Index (as described in U.S. Patent No. 4,016,218) of the HMCM-58 product of Example 13 was determined to be 0.3 at 316°C. This value falls within the classification of the more open structures having 12- membered rings. Hence, it is concluded from the catalytic Constraint Index Test result that HMCM-58 contains at least a 12-membered ring structure.

EXAMPLE 17 A sample of the HMCM-58 product of Example 14 was subjected to sorption evaluation. Figure 2 shows the 2,2- dimethylbutane (2,2-DMB) sorption measurements at 90°C for this sample. The rapid uptake of 2 , 2-dimethylbutane indicates a very open pore structure.

EXAMPLE 18 A sample of the HMCM-58 product of Example 14 was also subjected to n-hexane sorption evaluation. Figure 3 shows the n-hexane sorption measurement at 30°C for this sample. The rapid uptake of n-hexane into the HMCM-58 sample indicates a very open structure.

EXAMPLE 19 A solution was prepared by dissolving 0.99 g of boric acid and 4.93 g KOH pellets into 138.24 g deionized water.

After the boric acid and KOH dissolved, 13.54 g of the organic template benzylquinuclidinium bromide was added to the solution and stirred until it dissolved. This solution was then transferred to a 300 ml stainless-steel autoclave. Now 48.0 g of colloidal silica sol (30% SiO„) was added directly to the autoclave and the mixture was stirred for 2 minutes to produce a uniform, fluid hydrogel.

The autoclave was sealed, and stirring and heating were begun immediately. The autoclave was heated at a rate of 2°C/min. to the reaction temperature of 170"C. The autoclave was then held at 170°C for 7 days with stirring at 400 rpm.

The resultant product was filtered, washed with boiling water, then dried in an air stream on the filter under an infrared heat lamp. The dried product was analyzed by X-ray powder diffraction analysis which showed that the material was crystalline borosilicate MCM-58.

SUBSTITUTESHEET(RUIE2S _I