DE3886952T2 - SYNTHETIC, POROUS, CRYSTALLINE MATERIAL, AND THEIR SYNTHESIS AND USE. - Google Patents

Description

This invention relates to a synthetic porous crystalline material, to a process for its preparation and to its use in the catalytic conversion of organic compounds.

Zeolite materials, both natural and synthetic, have been shown in the past to have catalytic properties for various types of hydrocarbon conversion. Certain zeolite materials are required, porous crystalline aluminosilicates with a particular crystalline structure, as determined by X-ray diffraction, within which there are a large number of smaller voids, which may be interconnected by a number of even smaller channels or pores. These voids and pores are of uniform size within a specific zeolite material. Since the dimensions of these pores are such that the adsorption of molecules of certain dimensions is permitted, while those of larger dimensions are retained, these materials have become known as "molecular sieves" and are used in many ways to exploit these properties.

These molecular sieves, both natural and synthetic, include a wide variety of crystalline silicates containing positive ions. These silicates can be described as a rigid three-dimensional lattice of SiO₄ and the oxide of an element of Group IIIA of the periodic table, e.g. AlO₄, in which the tetrahedra are interconnected by the sharing of oxygen atoms, whereby the ratio of the sum of the Group IIIA elements, e.g. aluminium, and the silicon atoms to the oxygen atoms is 1:2. The electrochemical valence of the tetrahedra containing the Group IIIA element, e.g. aluminium, is balanced by the inclusion of a cation in the crystal, e.g. an alkali metal or alkaline earth metal cation. This can be expressed as the ratio of the Group IIIA element, e.g. aluminium, to the number of different cations, e.g. Ca/2, Sr/2, Na, K or Li, equal to one. One type of cation can be exchanged either completely or partially by another type of cation using ion exchange techniques in a conventional manner. By this cation exchange it has been possible to vary the properties of a given silicate by appropriate selection of the cation.

Conventional processes have led to the production of a wide variety of synthetic zeolites. Many of these zeolites have been designated by a letter or other suitable symbols, such as zeolite A (US Patent 2,882,243), zeolite X (US Patent 2,882,244), zeolite Y (US Patent 3,130,007), zeolite ZK-5 (US Patent 3,247,195), zeolite ZK-4 (US Patent 3,314,752), zeolite ZSM-5 (US Patent 3,702,886), zeolite ZSM-11 (US Patent 3,709,979), zeolite ZSM-12 (US Patent 3,832,449), zeolite ZSM-20 (US Patent 3,972,983), ZSM-35 (US Patent 4,016,245) and zeolite ZSM-23 (US Patent 4,076 842).

The SiO2/Al2O3 ratio of a given zeolite is often variable. For example, zeolite X can be made with SiO2/Al2O3 ratios of 3 to 2, zeolite Y from 3 to 6. For some zeolites, the upper limit of the SiO2/Al2O3 ratio is not fixed. ZSM-5 is one such example where the SiO2/Al2O3 ratio is at least 5 and up to the limits of current analytical measurement techniques. US Patent 3,941,871 (Re 29,948) describes a porous crystalline silicate prepared from a reaction mixture containing no intentionally added alumina and exhibiting the X-ray diffraction pattern characteristic of ZSM-5. US Patent Nos. 4,061,724, 4,073,865 and 4,104,294 describe a crystalline silicate with varying alumina and metal contents.

According to a first aspect, this invention consists in a synthetic porous crystalline material characterized by an X-ray diffraction pattern comprising the values substantially set out in Table I of the description and having equilibrium adsorption capacities of more than than 10 wt.% for water, more than 4.5 wt.% for cyclohexane vapor and more than 10 wt.% for n-hexane vapor.

The porous crystalline material of the present invention appears to be related to the compositions referred to as "PSH-3" described in U.S. Patent 4,439,409. However, the crystalline material of the present invention does not appear to contain all of the components that appear to be present in the PSM-3 compositions. In particular, the composition of this invention is not contaminated with other crystal structures, e.g., ZSM-12 or ZSM-5, exhibits unusual sorption capacities, and unique catalytic applicability compared to the PSH-3 compositions synthesized in U.S. Patent 4,439,409.

The crystalline material of this invention can be synthesized by crystallizing a reaction mixture containing sources of the required oxides together with the hexamethyleneimine precursor. However, it has been found to be important to use a silica source having a relatively high solids content, particularly when the crystalline material of this invention is a silicate.

Accordingly, in a second aspect, this invention consists in a process for preparing the synthetic crystalline material of the first aspect of the invention, which comprises preparing a reaction mixture capable of forming said material upon crystallization, said reaction mixture containing sufficient amounts of alkali or alkaline earth metal cations, a source of a tetravalent oxide YO₂ containing at least about 30 wt% solid YO₂, a source of a trivalent oxide X₂O₃, water and hexamethyleneimine, and maintaining said reaction mixture under sufficient crystallization conditions until crystals of said material are formed.

The crystalline material of this invention has the composition having the molar ratio: X₂O₃: (n)YO₂ wherein X is a trivalent element, e.g. aluminium, boron, iron and/or gallium, preferably aluminium, Y is a tetravalent element, e.g. silicon and/or germanium, preferably silicon, and n is at least 10, usually from 10 to 150, preferably from 10 to 60 and most preferably from 20 to 40. In the form so synthesized, the material has the following formula on an anhydrous basis and in terms of moles of oxides per n moles of YO₂:

(0.005-0.1)Na₂O:(1-4)R:X₂O₃:nYO₂

where R is the organic moiety. The components Na and R are associated with the material as a result of their presence during crystallization and are readily removed by post-crystallization processes as will be particularly described hereinafter.

The crystalline material of the invention is thermally stable and exhibits a large specific surface area (more than 400 m2/g) and an unusually high sorption capacity compared to similar crystal structures. As is clear from the formula given above, the crystalline material of this invention is synthesized almost free of Na cations. It can therefore be used as a catalyst with acid activity without an exchange step. However, the original sodium cations of the synthesized material can be replaced, to the desired extent, at least partially by ion exchange with other cations according to methods well known in the art. Preferred exchanging cations include metal ions, hydrogen ions, a hydrogen precursor, e.g. ammonium, ions and mixtures thereof. Particularly preferred cations are those that tailor the catalytic activity for particular hydrocarbon conversion reactions. These include hydrogen, rare earth metals and metals from groups IIA, IIIA, IVA, IB, IIB, IIIB, IVB and VIII of the periodic table of elements.

In its calcined form, the crystalline material of the invention appears to be composed of a single crystal phase with little or no detectable impurity crystal phases and has an X-ray diffraction pattern which distinguishes it from the patterns of other known crystalline materials by the lines shown in Table I below: Table I d-Plane spacing (Å) Relative intensity, I/Io x 100

More specifically, it is distinguished by the lines listed in Table II below: Table II d-Plane spacing (Å) Relative intensity. I/Io x 100

and more specifically by the lines listed in Table III below: Table III d-Latch spacing (Å) Relative intensity, I/Io x 100

In particular, the calcined crystalline material of the invention has an X-ray diffraction pattern comprising the lines shown in Table IV below Table IV d-Plane spacing (Å) Relative intensity. I/Io x 100This Values were determined by standard methods. The radiation was the K-α doublet of copper and a diffractometer equipped with a scintillation counter and associated computer was used. The peak heights I and positions as a function of 2 theta, where theta is the Bragg angle, were determined by algorithms in the computer connected to the diffractometer. From this the relative intensities 100 I/Io were determined, where Io is the intensity of the strongest line or peak and d (observed) is the interplanar spacing in Angstrom units (Å) corresponding to the strongest lines. In Tables I to IV the relative intensities are given as symbols W = weak, M = medium, S = strong and VS = very strong. In terms of intensities these can be generally referred to as:

W = 0 - 20

M = 20 - 40

S = 40 - 60

VS = 60 - 100

It should be clear that this X-ray diffraction pattern is characteristic of all types of the crystalline composition of the invention. The sodium form and also the other cationic forms show essentially the same pattern with some slight shifts in the interplanar spacing and a small deviation in the relative intensity. Other minor changes may occur, depending on the ratio Y to X, e.g. silicon to aluminum, of the particular sample as well as the degree of heat treatment.

The crystalline material of this invention can be prepared from a reaction mixture containing sources of alkali or alkaline earth metal (M), e.g. sodium or potassium, a cation, an oxide of the trivalent element X, e.g. aluminum, an oxide of the tetravalent element Y, e.g. silicon, the organic conductive agent (R) described in more detail hereinafter, and water, said reaction mixture having a composition based on the molar ratios of the oxides within the following ranges: Reactants Advantageous Preferred

It has been found that crystallization of the material of the invention is favored when the source of YO2 contains at least 30 wt.% solid YO2, particularly when YO2 is silica. Suitable commercial silica sources include Ultrasil (a precipitated spray dried silica containing about 90 wt.% silica) and HiSil (a precipitated hydrated SiO2 containing about 87 wt.% silica, about 6 wt.% free H2O and about 4.5 wt.% bound H2O of hydration and having a particle size of about 0.02 µm). When a different source of silica is used, e.g., grade Q (a sodium silicate consisting of about 28.8 wt.% SiO2, 8.9 wt.% Na2O, and 62.3 wt.% H2O), it has been found that crystallization yields little or no crystalline material of this invention and instead impurity phases of other crystal structures are formed, e.g., ZSM-12. The YO2 source thus preferably contains at least 30 wt.% solid YO2, preferably silica, and more preferably at least 40 wt.% solid YO2.

The organic conducting agent (R) used in the synthesis of the crystalline material according to the invention from the above-mentioned reaction mixture is hexamethyleneimine, which has the following structural formula:

The crystallization of the crystalline material according to the invention can be carried out either in a static or stirred state in a suitable reactor vessel, eg polypropylene vessels or Teflon-lined or stainless steel autoclaves. Crystallization is generally carried out at a temperature of 80 to 225ºC for a period of 24 hours to 60 days. The crystals are then separated from the liquid and recovered.

Crystallization is facilitated by the presence of at least 0.01%, preferably 0.10% and more preferably 1% of crystal nuclei of the desired crystalline product (this is based on total weight).

Before use as a catalyst or adsorbent, the synthesized crystalline material should be calcined to remove some or all of the organic constituents.

The crystalline material of the invention can be used in close combination with a hydrogenation component as a catalyst, e.g. tungsten, vanadium, molybdenum, rhenium, nickel, cobalt, chromium, manganese, or a noble metal such as platinum or palladium, when a hydrogenation/dehydrogenation function is to be performed. This component can be present in the composition by simultaneous crystallization, base exchange into the composition, impregnation into the composition, or by being intimately physically mixed therewith. This component can be impregnated into or onto the composition, e.g. in the case of platinum by treating the silicate with a solution containing an ion containing a platinum metal. Suitable platinum compounds for this purpose thus include chloroplatinic acid, platinum (II) chloride and various compounds containing the platinum amine complex.

The crystalline material of the present invention can be formed into a variety of particle sizes. Generally speaking, these particles can be in the form of a powder, a granule or a shaped product, e.g. in the form of an extrudate. In the latter case, the crystalline Material can be extruded before drying, or partially dried and then extruded.

When the crystalline material of this invention is used either as an adsorbent or as a catalyst in an organic compound conversion process, it should be at least partially dehydrated. This can be done by heating it in an atmosphere, e.g. air, nitrogen, etc. and at atmospheric pressure, vacuum or pressure, to a temperature in the range of 200 to 595°C for a period of between 30 minutes and 48 hours. Dehydration can also be done at room temperature by simply placing the silicate in a vacuum, but a longer period of time is necessary to obtain a sufficient amount of dehydration.

The crystalline material of the invention can be used to catalyze a wide variety of organic conversion processes, these include, for example, the hydration of C2 - C7 olefins, e.g. propylene, to alcohols and ethers, wherein the reaction conditions include a temperature of from 50 to 300°C, preferably from 90 to 250°C, a pressure of at least 5 kg/cm2, preferably at least 20 kg/cm2, and a molar ratio of water/olefin of from 0.1 to 30, preferably from 0.2 to 15.

As is the case with many catalysts, the crystalline material of this invention can be incorporated into another material that is resistant to the temperatures and other conditions used in organic conversion processes. These 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 can be either naturally occurring or in the form of gelatinous precipitates or gels, including mixtures of silica and metal oxides. The use of a material in association with the new crystal, combined therewith or present during the synthesis of the new crystal, which active tends to alter the conversion and/or selectivity of the catalyst in certain organic conversion processes. Inactive materials conveniently serve as diluents to control the amount of conversion in a given process so that the products can be obtained economically and consistently without resorting to other means of controlling the reaction rate. These materials can be incorporated into naturally occurring clays, e.g., bentonite and kaolin, to improve the crush strength of the catalyst under ordinary process conditions. These materials, namely clays, oxides, etc., act as binders for the catalyst. It is desirable to form a catalyst with good crush strength because in ordinary application it is desirable to prevent collapse of the catalyst into powdery materials. These clay binders have normally been used only to improve the crush strength of the catalyst.

Naturally occurring clay materials which can be composed with this new crystal include the montmorillonite and kaolin groups, these groups including the subbentonites and the kaolins commonly known as Dixie, McNamee, Georgia and Florida clays, and others in which the main mineral constituent is halloysite, kaolinite, dickite, nactrite or anauxite. These clays can be used in the raw state as originally mined or can be initially subjected to calcination, acid treatment or chemical modification. Binders useful in the composition with the crystal of the invention also include inorganic oxides, particularly alumina.

In addition to the above materials, the new crystal can be composed 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-alumina-thoria, silica-alumina-zirconia, Silica-alumina-magnesia and silica-magnesia-zirconia.

The relative proportions of the finely divided crystalline material and the inorganic oxide matrix vary widely, with the crystal content ranging from 1 to 90% by weight and more typically, particularly when the composite material is made in the form of beads, ranging from 2 to 80% by weight of the composite material.

This invention will be described in more detail with reference to the examples and the accompanying drawings, in which Figures 1 to 5 show X-ray diffraction patterns of the calcined products of Examples 1, 3, 4, 5 and 9, respectively. When sorption values are given in the examples to compare the sorption capacities of water, cyclohexane and/or n-hexane, these were the equilibrium adsorption values determined as follows:

A weighed sample of the calcined adsorbent was contacted with the desired pure adsorbate vapor in an adsorption chamber, evacuated to less than 1 mm, and contacted with 12 torr of water vapor and 40 torr of n-hexane or cyclohexane vapor at a pressure less than the vapor/liquid equilibrium pressure of the corresponding adsorbate at 90°C. This pressure was kept constant (within about ± 0.5 mm) by the controlled addition of adsorbate vapor by a manostat during the adsorption period, which did not exceed 8 hours. When the adsorbate had been adsorbed by the new crystal, the decrease in pressure caused the manostat to open a valve which admitted more adsorbate vapor into the chamber to restore the above-mentioned controlled pressure. Sorption was complete when the pressure change was not sufficient to activate the manostat. The weight gain was calculated as the adsorption capacity of the sample in g/100 g of the calcined adsorbent. The synthetic material of this invention always showed equilibrium adsorption values of more than 10 wt.% for water vapor, more than 4.5 wt.%, typically more than 7 wt.% for cyclohexane vapor and more than 10 wt.% for n-hexane vapor.

When checking the α value, it must be noted that this α value is an approximate characterization of the catalytic cracking activity of the catalyst compared with a standard catalyst and indicates the relative rate constant (rate of conversion of n-hexane per volume of catalyst per unit time) compared with that of the highly active silica-alumina cracking catalyst, which is assumed to be α = 1 (rate constant = 0.016 s-1). This α value check is described in U.S. Patent 3,354,078 and in Journal of Catalysis, Vol. IV, pp. 522-529 (August 1965). It is important to note that for a given crystalline silicate catalyst, its own rate constants for many acid-catalyzed reactions are proportional to the α value, namely the rates for the disproportionation of toluene, the isomerization of xylene, the conversion of alkenes, and the conversion of methanol (see "The Active Site of Acidic Aluminosilicate Catalysts," Nature, Vol. 309, No. 5969, pp. 588-591, June 14, 1984).

example 1

12.86 g of sodium aluminate (43.5% Al2O3, 32.2% Na2O, 25.6% H2O) were dissolved in a solution containing 12.8 g of a 50% NaOH solution and 1320 g of H2O. 57.6 g of hexamethyleneimine were added. The resulting solution was added to 109.4 g of Ultrasil, a pleasing spray dried silica (about 90% SiO2).

The reaction mixture had the following composition in molar ratios:

SiO₂/Al₂O₃ = 30.0

OH⊃min;/SiO₂ = 0.18

H₂O/SiO₂ = 44.9

Na/SiO₂ = 0.18

R/SiO₂ = 0.35

where R is hexamethyleneimine.

The mixture was crystallized in a stainless steel reactor with stirring at 150ºC for 7 days. The crystalline product was filtered, washed with water and dried at 120ºC. After calcination for 20 hours at 583ºC, the X-ray diffraction pattern contained the main lines listed in Table V. Figure 1 shows the X-ray diffraction pattern of this calcined product. The sorption capacities of the calcined material were measured as follows:

H₂O (12 Torr) 15.2 wt.%

Cyclohexane (40 Torr) 14.6 wt.%

n-Hexane (40 Torr) 16.7 wt.%

The specific surface area of this calcined crystalline material was measured to be 494 m²/g.

The chemical composition of this calcined material was determined as follows: Component wt.% Table V 2 Theta, degree d-Latium spacing (Å)

Example 2

A portion of the calcined crystalline product of Example 1 was tested in the α-test and an α-value of 224 was found.

Examples 3 to 5

Three separate synthesis reaction mixtures were prepared with the compositions shown in Table VI. These mixtures were prepared with sodium aluminate, sodium hydroxide, Ultrasil, hexamethyleneimine (R) and water. The mixtures were maintained in a stirred (350 rpm) stainless steel autoclave at autogenous pressure at 150°C, 143°C and 150°C for 7, 8 and 6 days, respectively. The solids were separated from any unreacted components by filtration and then washed with water, followed by drying at 120°C. The crystals of the product were analyzed by X-ray diffraction, sorption, specific surface area and chemical analyses. These products were found to be the new crystalline material of this invention. The results of the sorption, specific surface area and chemical analyses are also shown in Table VI. The X-ray diffraction patterns of the calcined products (538 °C, for 3 hours) of Examples 3, 4 and 5 are shown in Figures 2, 3 and 4, respectively. The sorption and specific surface area measurements were for the calcined product. Table VI Example number Synthesis mixture, molar ratios Composition of product, wt.% Ash Molar ratio adsorption, wt.% Cyclohexane n-hexane Specific surface area, m²/g

Example 6

Quantities of the calcined (538°C for 3 hours) crystalline silicate products of Examples 3, 4 and 5 were tested in the α test and found to have α values of 227, 180 and 187, respectively.

Example 7

A calcined sample of the crystalline silicate of Example 4 was impregnated with a Pt(NH3)4Cl2 solution to about 1 wt% Pt. This material was then heated in air at 349°C for 3 hours.

Example 8

1 g of the resulting product of Example 7 was added as a catalyst to a small reactor equipped with a preheater and embedded in a thermocouple. The catalyst was then heated to 482°C with flowing hydrogen to reduce the Pt component. n-decane and hydrogen were passed over the catalyst to obtain a WHSV of 0.4 h-1 for decane and a hydrogen/hydrocarbon molar ratio of 100/1. The reaction was carried out in the temperature range of 130 - 250°C and at atmospheric pressure.

The results of this experiment are summarized in Table VII along with the results of the same experiment but changing the crystalline material to ZSM-5 (US Patent 3,702,886), ZSM-11 (US Patent 3,709,979) and Zeolite Beta (US Patent 3,308,069) which are listed for comparison purposes. It is observed that the crystalline silicate of the present invention is a very active catalyst for the hydroconversion of n-decane and has good isomerization activity. In Table VII, "5MN/2MN" is the molar ratio of 5-methylnonane/2-methylnonane. Due to the position of its methyl group, 5-methylnonane presents a slightly greater steric hindrance to entry into the zeolite pores. The ratio 5MN/2MN provides information about the porosity of the tested zeolite. Table VII Zeolite Catalyst SiO₂/Al₂O₃ Molar Ratio of Zeolite Temp.(ºC) for 50% Conversion % Isomers at 50% Conversion Example 7 Beta

Example 9

To demonstrate the more extensive approach to the crystalline material of this invention, 1200 g of hexamethyleneimine was added to a solution containing 268 g of sodium aluminate, 267 g of a 50% NaOH solution and 11800 g of H2O. To this combined solution was added 2280 g of Ultrasil silica. The mixture was crystallized with stirring (about 200 rpm) at 145°C in a 5 gallon reactor. The crystallization time was 95 hours. The product was washed with water and dried at 120°C.

The X-ray diffraction pattern of the calcined (538°C) product crystals is shown in Figure 5 and proves that this product is the crystalline material of this invention. The chemical composition of the product, the specific surface area and the adsorption analysis results were as follows: Table VIII Composition of the product SiO₂/Al₂O₃, molar ratio Adsorption, wt.% Cyclohexane n-hexane Specific surface area, m²/g

Example 10

A 25 g quantity of the solid crystal product of Example 9 was calcined in an atmosphere of flowing nitrogen at 538°C for 5 hours, after which it was purged with 5% oxygen gas (balance N2) for an additional 16 hours at 538°C.

Individual 3 g samples of the calcined material were separately ion exchanged with 100 ml of 0.1 N TEABr, TPABr and LaCl3 solution. Each exchange was carried out for 24 hours at ambient temperature and repeated three times. The exchanged samples were collected by filtration, washed with water to remove halide and dried. The compositions of the exchanged samples are summarized in the table below and show the exchange capacity of the crystalline silicate of the invention for different ions. Exchange ions Ionic composition, wt.%

Example 11

The above La-exchanged sample was brought to a size of 14 to 25mesh and then placed in Air at 538ºC. The calcined material had an α-value of 173.

Example 12

The calcined sample of the La-exchanged material of Example 11 was subjected to a severe steam treatment in 100% steam at 649ºC for 2 hours. This steamed sample had an α value of 22, which shows that the crystalline silicate has very good stability under severe hydrothermal treatment.

Example 13

To prepare the crystal of the invention, where X represents boron, an amount of 17.5 g of boric acid was added to a solution containing 6.75 g of a 45% KOH solution and 290 g of H₂O. To this was added 57.8 g of Ultrasil silica and the mixture was thoroughly homogenized. An amount of 26.2 g of hexamethyleneimine was added to the mixture.

The reaction mixture had the following composition in molar ratios:

SiO₂/B₂O₃ = 6.1

OH₂/SiO₂ = 0.06

H₂O/SiO₂ = 19.0

K/SiO₂ = 0.06

R/SiO₂ = 0.30

where R is hexamethyleneimine.

The mixture was crystallized in a stainless steel reactor at 150ºC for 8 days with stirring. The crystalline product was filtered, washed with water and dried at 120ºC. A portion of the product was calcined at 540ºC for 6 hours and found to have the following sorption capacities:

H₂O (12 Torr) 11.7 wt.%

Cyclohexane (40 Torr) 7.5 wt.%

n-Hexane (40 Torr) 11.4 wt.% The specific surface area of the calcined crystalline material was measured to be 405 m²/g.

The chemical composition of the calcined material was determined as follows:

N 1.94 wt.%

Na 175 ppm

K 0.60 wt.%

Boron 1.04 wt.%

Al₂O₃ 920 ppm

SiO₂ 75.9 wt.%

Ash 74.11 wt.%

SiO₂/Al₂O₃, molar ratio 1406

SiO₂/ (Al+B) ₂O₃, molar ratio 25.8

Example 14

A portion of the calcined crystalline product of Example 13 was treated with NH4Cl and recalcined. The final crystalline product was tested in the α test and found to have an α value of 1.

Example 15

To prepare the crystalline material of the invention, where X comprises boron, an amount of 35.0 g of boric acid was added to a solution comprising 15.7 g of a 50% NaOH solution and 1160 g of H₂O. To this solution was added 240 g of silicon dioxide, HiSil, followed by 105 g of hexamethyleneimine. The reaction mixture had the following composition in molar ratios:

SiO₂/B₂O₃ = 12.3

OH⊃min;/SiO₂ = 0.056

H₂O/SiO₂ = 18.6

Na/SiO2 = 0.056

R/SiO₂ = 0.30

where R is hexamethyleneimine. The mixture was crystallized in a stainless steel reactor at 300ºC for 9 days with stirring. The crystalline product was filtered, washed with water and dried at 120ºC. The sorption capacities of the calcined material (6 hours at 540ºC) were measured as follows:

H₂O (12 Torr) 14.4 wt.%

Cyclohexane (40 Torr) 4.6 wt.%

n-Hexane (40 Torr) 14.0 wt.%

The specific surface area of the calcified crystalline material was measured to be 438 m²/g.

The chemical composition of the calcined material was determined as follows: Component wt. % SiO₂/Al₂O₃, molar ratio SiO₂/(A1+B)₂O₃, molar ratio

Example 16

A portion of the calcined crystalline product of Example 15 was tested in the α-test and an α-value of 5 was found.

Example 17

To demonstrate the importance of using the silica source containing at least 30% solid silica in the process of the invention, Example 3 was repeated but using Q grade sodium silicate as the silica source (containing only about 29% solid silica by weight). In this example, 67.6 g of aluminum sulfate was dissolved in a solution of 38.1 g of H₂SO₄ (96.1%) and 400 g of water. The resulting solution was treated with 120 g of hexamethyleneimine and added to a mixture of 712.5 g of sodium silicate grade Q (28.8% SiO₂ and 8.9% Na₂O) and 351 g of water. The resulting mixture had the following composition expressed as molar ratios:

SiO₂/Al₂O₃ = 30.0

OH/SiO2 = 0.18

H₂O/SiO₂ = 19.4

Na/SiO₂ = 0.60

R/SiO₂ = 0.35

was thoroughly mixed and crystallized with stirring in a stainless steel reactor at 246°C for 8 days. The product solids were separated from the unreacted components by filtration, then washed with water, and then dried at 120°C. The product was analyzed by X-ray diffraction and found to be a mixture of an amorphous material, magadiite and mordenite. No crystals of the invention were found.

Example 18

In this example, the properties of the crystalline material of the present invention in the hydration of propylene were compared with those of ZSM-12 and PSH-3 prepared according to Example 4 of U.S. Patent No. 4,439,409.

The crystalline material of the present invention was prepared by adding 15.9 parts by weight of hexamethyleneimine to a mixture containing 3.5 parts of 50% NaOH, 3.5 parts of sodium aluminate, 30.1 parts of Ultrasil VN3 silica and 156 parts of deionized H₂O. The reaction mixture was immediately heated to 290°F (143°C) and stirred at that temperature in an autoclave to effect crystallization. After complete crystallinity was achieved, the resulting crystals were separated from the residual liquid by filtration, washed with water and dried. A portion of the crystals were combined with alumina to form a mixture of 65 parts by weight of zeolite and 35 parts by weight of alumina. Sufficient water was added to the mixture so that the resulting catalyst could be extruded. This catalyst was activated by calcination in nitrogen at 1000ºF (540ºC), then exchanged with 1.0N aqueous ammonium nitrate and calcined in air at 1000 to 1200ºF (540 to 650ºC).

The ZSM-12 was prepared by adding one part by weight of ZSM-12 seed crystals to a mixture containing 41.5 parts of Hi-Sil 233 silica, 67.7 parts of 50% tetraethylammonium bromide, 7.0 parts of 50% NaOH and 165.4 parts of deionized H2O. The reaction mixture was immediately heated to 280°F (138°C) and stirred at that temperature in an autoclave to crystallize. After complete crystallinity was achieved, the resulting crystals were separated from the remaining liquid by filtration, washed with water and dried. One part of the crystals was combined with alumina to form a mixture of 65 parts by weight of zeolite and 35 parts of alumina. To this mixture, sufficient water was added so that the resulting catalyst could be formed into extrudates. This catalyst was activated by calcining in nitrogen at 1000ºF (540ºC), then exchanged with 1.0N aqueous ammonium nitrate and calcined at 1200ºF (650ºC).

Hydration of propylene was carried out at a temperature of 330ºF (166ºC), a pressure of 1000 psig (7000 kPa) and a WHSV of propylene of 0.6. The results of 2 days under steam are compared in Table IX below. Table IX Material of the Invention Propylene Conversion, % Water Conversion, % IPA Selectivity DIPE Selectivity Oligomer Selectivity IPA = Isopropyl Alcohol DIPE = Diisopropyl Ether

The above results clearly demonstrate the advantageous properties of the material according to the invention in comparison with PSH-3 as well as ZSM-12, by achieving a higher conversion rate in conjunction with a good selectivity towards disopropylbenzene and a low production of propylene oligomers.

Claims (10)

1. Synthetic porous crystalline material, characterized by an X-ray diffraction pattern which essentially comprises the values shown in Table I below and has equilibrium adsorption capacities of more than 10% by weight for water vapor, more than 4.5% by weight for cyclohexane vapor and more than 10% by weight for n-hexane vapor: Table I d-Latch spacing (Å) Relative intensity, I/Iox100 2. Synthetic porous crystalline material according to claim 1, characterized by an X-ray diffraction pattern which essentially comprises the values listed in Table II below: Table II d-Latch spacing (Å) Relative intensity, I/Iox100 3. Synthetic porous crystalline material according to claim 1, characterized by an X-ray diffraction pattern which essentially comprises the values listed in Table III below: Table III d-Latch spacing (Å) Relative intensity, I/Iox100 4. Synthetic porous crystalline material according to claim 1, characterized by an X-ray diffraction pattern which essentially comprises the values listed in Table IV below: Table IV d-Latch spacing (Å) Relative intensity, I/Iox100 5. Crystalline material according to any one of the preceding claims having a composition comprising the molar ratio: X₂O₃: (n) YO₂, where n is at least 10, X is a trivalent element and Y is a tetravalent element. 6. A crystalline material according to claim 5, wherein x comprises aluminum and Y comprises silicon. 7. Crystalline material according to claim 6, wherein n is 20 to 40. 8. A process for preparing the synthetic crystalline material of claim 5, said process comprising preparing a reaction mixture capable of forming said marial upon crystallization, said reaction mixture containing sufficient amounts of alkali or alkaline earth metal cations, a source of a tetravalent Y oxide containing at least 30% by weight of solid YO₂, a source of a trivalent X oxide, water, and hexamethyleneimine, and maintaining said reaction mixture under sufficient crystallization conditions until crystals of said material are formed. 9. The process according to claim 8, wherein the reaction mixture has a molar composition within the following ranges: YO₂/X₂O₃ = 10 to 80 H₂O/YO₂ = 5 to 100 OH⊃min;/YO₂ = 0.01 to 1.0 M/YO2 0.01 to 2.0 R/YO₂ 0.05 to 1.0 where R is hexamethyleneimine and M is an alkali or alkaline earth metal. 10. The process according to claim 8, wherein the reaction mixture has a molar composition within the following ranges: YO₂/X₂O₃ = 10 to 60 H₂O/YO₂ = 10 to 50 OH⊃min;/YO₂ = 0.1 to 0.5 M/YO₂ = 0.1 to 1.0 R/YO₂ = 0.1 to 0.5