WO1993007106A1

WO1993007106A1 - Isoparaffin:olefin alkylation

Info

Publication number: WO1993007106A1
Application number: PCT/US1992/008114
Authority: WO
Inventors: Altaf Husain; Albin Huss, Jr.; Donald Joseph Klocke; Hye Kyung Cho Timken
Original assignee: Mobil Oil Corporation
Priority date: 1991-10-10
Filing date: 1992-09-24
Publication date: 1993-04-15
Also published as: AU2668792A; US5254792A

Abstract

The invention provides an isoparaffin:olefin alkylation process comprising contacting isoparaffin and olefin with the synthetic porous crystalline material MCM-49 which is characterized, in its uncalcined form, by an X-ray diffraction pattern including the lines listed in Table 1.

Description

ISOPARAFFIN:OLEFIN ALKYLATION

The present invention relates to an isoparaffin-olefin alkylation process carried out in the presence of a synthetic porous crystalline material to provide an alkylate product useful, inter alia, as an octane enhancer for gasoline.

As a result of the curtailment in the use of tetraethyl lead as an octane-improving additive for gasoline, not only has the production of unleaded gasoline increased but the octane number specification of all grades of gasoline have increased as well. Isoparaffin-olefin aklylation is a key route to the production of highly branched paraffin octane enhancers which are to be blended into gasolines. Alkylation involves the addition of an alkyl group to an organic molecule. Thus, an isoparaffin can be reacted with an olefin to provide an isoparaffin of higher molecular weight. Industrially, alkylation often involves the reaction of C_-C,_ olefins with isobutane in the presence of an acidic catalyst.

Alkylates are valuable blending components for the manufacture of premium gasoline due to their high octane ratings.

In the past, alkylation processes have included the use of hydrofluoric acid or sulfuric acid as catalysts under controlled temperature conditions. Low temperatures are utilized in the sulfuric acid process to minimize the undesirable side reaction of olefin polymerization and the acid strength is generally maintained at 88-94 percent by the continuous addition of fresh acid and the continuous withdrawal of spent acid. The hydrofluoric acid process is less temperature-sensitive and the acid is easily recovered and purified. The typical types of alkylation currently used to produce high octane gasoline blending component (processes such as hydrofluoric acid and sulfuric acid aklylation) have inherent drawbacks including acid consumption and disposal of corrosive materials. With the increasing demands for octane and the increasing environmental concerns,^' it is desirable to develop an alkylation process based on a solid catalyst system. The catalyst of the present invention offers a refiner a more environmentally acceptable alkylation process than the currently used hydrofluoric and sulfuric acid alkylation processes.

Crystalline metallosilicates, or zeolites, have been widely investigated for use in the catalysis of isoparaffin alkylation. For example, U.S. Patent No. 3,251,902 describes the use of a fixed bed of ion-exchanged crystalline aluminosilicate having a reduced number of available acid sites for the liquid phase alkylation of C.-C_₀ branched-chain paraffins with C_-C₁₂ olefins. The patent further discloses that the C.-C_p0 branched-chain paraffin should be allowed to substantially saturate the crystalline aluminosilicate before the olefin is introduced to the alkylation reactor.

U.S. Patent No. 3,549,557 describes the alkylation of isobutane with C₆-C_ olefins using certain crystalline aluminosilicate zeolite catalysts in a fixed, moving or fluidized bed system, the olefin being preferably injected at various points in the reactor.

U.S. Patent No. 3,644,564 discloses the alkylation of a paraffin with an olefin in the presence of a catalyst comprising a Group VIII nobel metal present on a crystalline aluminosilicate zeolite, the catalyst having been pretreated with hydrogen to promote selectivity.

U.S. Patent No. 3,647,916 describes an isoparaffin-olefin alkylation process featuring the use of an ion-exchanged crystalline aluminosilicate, isoparaffin/olefin mole ratios below 3:1 and regeneration of the catalyst.

U.S. Patent No. 3,655,813 discloses a process for alkylating C.-C₅ isoparaffins with C₃~C_g olefins using a crystalline aluminosilicate zeolite catalyst wherein a halide adjuvant is employed in the alkylation reactor. The isoparaffin and olefin are introduced into the alkylation reactor at specified concentrations and catalyst is continuously regenerated outside the alkylation reactor.

U.S. Patent No. 3,865,894 describes the alkylation of C -C isoparaffin with C -C monoolefin employing a substantially anhydrous acidic zeolite, for example acidic zeolite Y (zeolite HY) , and a halide adjuvant.

U.S. Patent No. 3,893,942 describes an isoparaffin alkylation process employing, as catalyst, a Group VIII metal-containing zeolite which is periodically hydrogenerated with hydrogen in the gas phase to reactivate the catalyst when it has become partially deactivated.

U.S. Patent No. 4,377,721 describes an isoparaffin-olefin alkylation process utilizing, as catalyst, ZSM-20, preferably HZSM-20 or rare earth cation-exchanged ZSM-20.

U.S. Patent No. 4,384,161 describes a process of alkylating isoparaffins with olefins to provide alkylate employing as catalyst a large pore zeolite capable of absorbing 2,2,4-trimethylpentane, e.g., ZSM-4, ZSM-20, ZSM-3, ZSM-18, zeolite Beta, faujasite, mordenite, zeolite Y and the rare earth metal-containing forms thereof, and a Lewis acid such as boron trifluoride, antimony pentafluoride or aluminum trichloride. The use of a large pore zeolite in combination with a Lewis acid in accordance with this patent is reported to greatly increase the acidity and selectivity of the zeolite thereby effecting alkylation with high olefin space velocity and low isoparaffin/olefin ratio. U.S. Patent No. 4,992,615 teaches isoparaffin:olefin alkylation in the presence of a synthetic porous crystalline material designated as MCM-22. MCM-22, as a composition of matter, is described in U.S. Patent 4,954,325. The present invention is directed to a process for isoparaffin:olefin alkylation in the presence of a novel porous crystalline material, referred to herein as MCM-49, which is related to but distinguishable from MCM-22. In accordance with the invention, it has been found that the novel porous crystalline material MCM-49 exhibits surprising activity and longevity for isoparaffin:olefin alkylation.

Accordingly, the invention resides in an isoparaffin:olefin alkylation process comprising contacting an isoparaffin and an olefin with a synthetic porous crystalline material which is characterized, in its uncalcined form, by an X-ray diffraction pattern including the lines listed in Table 1 below. The invention will now be more particularly described with refence to the accompanying drawings, in which:

Figures 1-5 are X-ray diffraction patterns of the as-synthesized crystalline material products of Examples l, 3, 5, 7 and 8, respectively; Figure 6 compares the 27Al MAS NMR spectra of calcined MCM-49 and calcined MCM-22; and

Figure 7 compares the isoparaffin:olefin alkylation performance of MCM-22 catalyst with that of isoparaffin:olefin alkylation performance of an MCM-49 catalyst of the present invention, showing weight percent C olefin conversion as a function of grams C olefin converted per gram of catalyst.

The porous crystalline material employed in the process of the invention, MCM-49, is characterized in its as-synthesized form by an X-ray diffraction pattern including the lines listed in Table 1 below:

TABLE I

Interplanar d-Spacin (A) Relative Intensity. I/Io x 100 13.15 + 0.26 w-s*

12.49 ± 0.24 vs

11.19 ± 0.22 m-s

6.43 + 0.12 W

4.98 ± 0.10 W 4.69 ± 0.09 w

3.44 + 0.07 VS

3.24 + 0.06 W

* shoulder.

The X-ray diffraction peak at 13.15 + 0.26 Angstrom Units (A) is usually not fully resolved for

MCM-49 from the intense peak at 12.49 + 0.24, and is observed as a shoulder of this intense peak. For this reason, the precise intensity and position of the 13.15

+ 0.26 Angstroms peak are difficult to determine within the stated range.

On calcination, the crystalline MCM-49 material of the invention transforms to a single crystal phase with little or no detectable impurity crystal phases having an X-ray diffraction pattern which is not readily distinguished from that of MCM-22 described in U.S.

Patent 4,954,325, but is distinguishable from the patterns of other known crystalline materials. The

X-ray diffraction pattern of the calcined form of

MCM-49 includes the lines listed in Table II below:

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/I 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 (60-100) , s = strong (40-60) , m = medium (20-40) and w = weak (0-20) .

As shown in Figure 6, a difference between calcined MCM-49 and calcined MCM-22 can be demonstrated by 27Al MAS NMR. When calcined completely to remove the organic material used to direct its synthesis, (Figure 6D) MCM-49 exhibits a 27Al MAS NMR spectrum different from that of fully calcined MCM-22 (Figure

6A) . In each case, calcination is effected at 538°C for 16 hours. The NMR spectra are obtained using a Bruker

MSL-400 spectrometer at 104.25 MHz with 5.00 KHz spinning speed, 1.0 μs excitation pulses (solution π/2

— 6/xs) , and 0.1S recycle times. The number of transients obtained for each sample is 2000 and the

27Al chemical shifts are referenced to a IM aqueous solution of A1(N0 ) at 0.0 ppm. As shown in Figures

6B and 6C, fully calcined MCM-22 exhibits a ²⁷A1 MAS

NMR spectrum in which the T, Al region can be simulated as comprising 3 peaks centered at 61, 55 and 50 ppm having approximate relative areas of 10:50:40. In contrast, fully calcined MCM-49 exhibits a ²⁷A1 MAS NMR spectrum in which the T, Al region can be simulated as comprising the 3 peaks center at 61, 55, and 50 ppm but having approximate relative areas of 20:45:35, together with a fourth broad peak centered at 54 ppm (Figures 6E and 6F) . Formation of the broad T- component does not appear to be dependent on the calcination environment (air or nitrogen) . Calcined MCM-49 also exhibits distinctly different catalytic properties than calcined MCM-22, particularly in the process of the invention.

The crystalline material used in the present invention has a composition comprising the molar relationship:

X₂0₃:(n)Y0₂, wherein X is a trivalent element, such as aluminum, boron, iron and/or gallium, preferably aluminum; Y is a tetravalent element such as silicon and/or germanium, preferably silicon; and n is less than 35, preferably from 11 to less than 20, most preferably from 15 to less than 20. More specifically, the crystalline material of this invention has a formula, on an anhydrous basis and in terms of moles of oxides per n moles of YO_?, as follows: (0.1-0.6)M₂O: (l-4)R:X₂0₃:nY0₂ 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 crystalline material of the invention is thermally stable and in the calcined form exhibits high

2 surface area (greater than 400 m /gm) and an

Equilibrium Adsorption capacity of greater than 10 wt.% for water vapor, greater than 4.3 wt.%, usually greater than 7 wt.%, for cyclohexane vapor and greater than 10 wt.% for n-hexane vapor.

The present crystalline material can be prepared from a reaction mixture containing sources of alkali or alkaline earth metal (M) , e.g. sodium or potassium, cation, an oxide of trivalent element X, e.g. aluminum, an oxide of tetravalent element Y, e.g. silicon, organic directing agent (R) , and water, said reaction mixture having a composition, in terms of mole ratios of oxides, within the following ranges: Reactants Broad Preferred

In the present synthesis method, the source of YO„ should predominately be solid YO_?, for example at least about 30 wt.% solid Y0_, in order to obtain the crystal 0 product of the invention. Where YO 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 SiO containing about 87 wt.% 5 silica, about 6 wt.% free H_0 and about 4.5 wt.% bound H₂0 of hydration and having a particle size of about 0.02 micron) favors crystalline MCM-49 formation from the above mixture. Preferably, therefore, the Y0_, e.g. silica, source contains at least about 30 wt.% solid Y0₂, e.g. silica, and more preferably at least about 40 wt.% solid YO , e.g. silica.

The directing agent R is selected from the group consisting of cycloalkylamine, azacycloalkane, diazacycloalkane, and mixtures thereof, alkyl -^> comprising from 5 to 8 carbon atoms. Non-limiting examples of R include cyclopentylamine, cyclohexylamine, cycloheptylamine, hexamethyleneimine, heptamethyleneimine, homopiperazine, and combinations thereof. However, in the case of hexamethyleneimine, 0 which is the preferred directing agent, it is found that pure MCM-49 can only be produced within the narrow silica/alumina range of 15 to less than 20, since above this range the product contains at least some MCM-22. Thus when R is hexamethyleneimine, the YO /X O. range in the reaction mixture composition tabulated above should be 15 to 25.

The R/M ratio is also important in the synthesis of MCM-49 in preference to other crystalline phases, such as MCM-22, since it is found that MCM-49 is favored when the R/M ratio is less than 3 and preferably is less than 1.

Crystallization of the present crystalline material can be carried out at either static or stirred conditions in a suitable reactor vessel, such as for example, polypropylene jars or teflon lined or stainless steel autoclaves. Crystallization is generally performed at a temperature of 80°C to 225°C for a time of 24 hours to 60 days. Thereafter, the crystals are separated from the mother liquid and recovered.

It should be realized that the reaction mixture components can be supplied by more than one source. The reaction mixture can be prepared either batchwise or continuously. Crystal size and crystallization time of the new crystalline material will vary with the nature of the reaction mixture employed and the crystallization conditions.

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. Useful seed crystals include MCM-22 and/or MCM-49. To the extent desired, the original sodium 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 cation^'s. 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.

When used as a catalyst for the process of the invention, the crystalline material of the invention may be subjected to treatment to remove part or all of any organic constituent. Typically this treatment involves heating at a temperature of 370 to 925°C for at least 1 minute and generally not longer than 20 hours.

As in the case of many catalysts, it may be desirable to incorporate the crystalline material with another material resistant to the conditions employed in the alkylation process of the invention. 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 the crystalline material, i.e. combined therewith or present during synthesis of the new crystal, which is active, may change the conversion and/or selectivity of the catalyst under certain alkylation conversion conditions. Inactive materials suitably serve as diluents to control the amount of conversion 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 commerical 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 the crystalline material 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, and anauxite. Such clays can be used in the raw state as originally mined or intitally subjected to calcination, acid treatment or chemical modification. Binders useful for compositing with the present crystal also include inorganic oxides, notably alumina.

In addition to the foregoing materials, the crystalline material 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-alumina-thoria, silica-alumina-zirconia silica-alumina-magnesia and silica-magnesia-zirconia. T e relative proportions of finely divided crystalline material and inorganic oxide matrix vary widely, with the crystal 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 2 to 80 weight percent of the composite. Feedstocks

Feedstocks useful in the present alkylation process include at least one isoparaffin and at least one olefin. The isoparaffin reactant used in the present alkylation process preferably has from 4 to 8 carbon atoms. Representative examples of such isoparaffins include isobutane, isopentane, 3-methylhexane, 2-methylhexane, 2, 3-dimethylbutane and 2,4-dimethylhexane. The olefin component of the feedstock preferably has 2 to 12 carbon atoms. Representative examples of such olefins include butene-2, isobutylene, butene-1, propylene, ethylene, hexene, octene, and heptene. The preferred olefins include the C. olefins, for example, butene-1, butene-2, isobutylene, or a mixture of one or more of these C. olefins, with butene-2 being the most preferred. Suitable feedstocks for the process of the present invention are described in U.S. Patent 3,862,258 to Huang et al. at column 3, lines 44-56.

The molar ratio of isoparaffin to olefin is generally from 1:1 to 100:1, preferably from 1:1 to 50:1, and more preferably from 5:1 to 20:1. Process Conditions

The operating temperature of the alkylation process herein can extend over a fairly broad range, e.g., from -25°C to 400°C, and preferably from 75°C to 200°C. The practical upper operating temperature will often be dictated by the need to avoid an undue occurrence of undesirable side reactions.

The pressures employed in the present process can extend over a considerably wide range, e.g., from subatmospheric pressure to 34600 kPa (5000 psig) , and preferably from 100 to 800 kPa (atmospheric pressure to 100 psig) . The amount of MCM-49 material used in the present alkylation process can be varied over relatively wide limits. In general, the amount of MCM-49 material as measured by the weight hourly space velocity (WHSV) based on olefin can range from 0.01 to 100 hr~ ,

—₁ pref rably from 0.04 to 10 hr

The isoparaffin and/or olefin reactants can be in either the vapor phase or the liquid phase and can be neat, i.e., free from intentional admixture or dilution with other material, or the reactants can be brought into contact with the catalyst composition with the aid of carrier gases or dilutents such as, for example, hydrogen or nitrogen. For example, the reactants can be introduced to the alkylation reaction zone together with one or more other materials which serve to enhance the overall conversion operation. Thus relatively small quantities of hydrogen and/or hydrogen donors can be present in the reaction zone to suppress catalyst aging. Water and/or materials such as alcohols which provide water under the alkylation conditions selected can also be introduced into the reaction zone for this purpose. Oxygen and/or other materials which tend to suppress oligomerization of the olefin feed can be present in the typically very small amounts which are effective to achieve this benefit.

The alkylation process of the present invention can be carried out as a batch-type, semi-continuous or continuous operation utilizing a fixed or moving bed of the MCM-49 catalyst component. A preferred embodiment entails use of a catalyst zone wherein the hydrocarbon charge is passed concurrently or countercurrently through a moving bed of particle-form catalyst. The latter, after use, is conducted to a regeneration zone where coke is removed, e.g. , by burning in an oxygen-containing atmosphere (such as air) at elevated temperature or by extracting with a solvent, after which the regenerated catalyst is recycled to the conversion zone for further contact with to organic reactants.

The invention will now be more particularly described with refence to the Examples.

In the Examples, whenever sorption data are set forth for comparison of sorptive capacities for water, cyclohexane and/or in 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 1.6 kPa (12 Torr) of water vapor and 5.3 kPa (40 Torr) of n-hexane or cyclohexane vapor, pressures less than the vapor-liquid equilibrium pressure of the respective adsorbate at 90°C. 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 new crystal, 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 g/100 g of calcined adsorbant. The new synthetic material of this invention always exhibits

Equilibrium Adsorption values of greater than about 10 wt.% for water vapor, greater than about 4.3 wt.%, usually greater than about 7 wt.% for cyclohexane vapor and greater than about 10 wt.% for n-hexane vapor. These vapor sorption capacities are a notable distinguishing feature of the present crystalline material.

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 give 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 ). The Alpha Test is described in U.S. Patent 3,354,078; in the Journal of Catalysis. Vol. 4, p. 527 (1965); Vol. 6, p. 278 (1966) ; and Vol. 61, p. 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. Vol. 61, p. 395.

EXAMPLE 1 A 1 part quantity of Al (SO ) x^H ₂° ^{was d}i^ssolvec* in a solution containing 1.83 parts of 50% NaOH solution and 13 parts of H„0. To this were added 1.78 parts of hexamethyleneimine (HMI) followed by 6.6 parts of amorphous silica precursor (46% solids) . The mixture was thoroughly mixed until uniform. The reaction mixture had the following composition in mole ratios:

The mixture was crystallized in a stirred reactor at 150°C for 4 days. The crystals were filtered, washed with water and dried at 120"C. A portion of the product was submitted for X-ray analysis and identified as the new crystalline material MCM-49. The material exhibited the X-ray powder diffraction pattern as shown in Table III and Figure 1.

The chemical composition of the product was, in wt.%:

N 1.81

Na 0.38

A1₂0₃ 7.1

SiO 72.8 Ash 79.2

The SiO /Al O molar ratio of this product was 17.4.

The sorption capacities, after calcining for 6 hours at 538 |C were, in wt.%: Cyclohexane 4.4 n-Hexane 12.8 H₂0 11.1

A portion of the sample was calcined in air for 16 hours at 538°C. This material exhibited the X-ray diffraction pattern shown in Table IV.

sh = Shoulder

* = Impurity peak

sh = Shoulder

* = Impurity peak EXAMPLE 2 The calcined portion of the product of Example 1 was ammonium exchanged and calcined at 538°C in air for 16 hours to provide the hydrogen form transformation product of the crystalline MCM-49. The Alpha Test proved this material to have an Alpha Value of 291.

EXAMPLE 3 A 1.45 part quantity of sodium aluminate was added to a solution containing 1 part of 50% NaOH solution and 53.1 parts H₂0. A 5.4 part quantity of HMI was added, followed by 10.3 parts of Ultrasil, a precipitated spray-dried silica (about 90% SiO,) . The reaction mixture was thoroughly mixed and transferred to a stainless steel autoclave equipped with a stirrer. The reaction mixture had the following composition in mole ratios:

Si0₂/Al₂0₃ = 25 OH~/Si0₂ = 0.19

Na/Sill. 0₂ = 0.19 HMI/Stll. 0₂ = 0.35

H₂0/SiO = 19.3

The mixture was crystallized with stirring at 1501C for 8 days. The product was identified as MCM-49 and had the X-ray pattern which appears in Table V and Figure 2.

The chemical composition of the product was, in wt.%:

N 2.29

Na 0.19 A1₂0₃ 6.3

Si0₂ 71.0

Ash 77.9

The silica/alumina mole ratio of the product was' 19.2. The sorption capacities, after calcining for 16 hours at 538IC were, in wt.%: Cyclohexane 9.9 n-Hexane 14.6

H₂0 ^' 15.1

A portion of the sample was calcined in air for 16 hours at 538°C. This material exhibited the X-ray diffraction pattern shown in Table VI.

+ = Non-crystallographic MCM-49 peak

* = Impurity peak

** = May contain impurity peak

sh = Shoulder

+ = Non-crystallographic MCM-49 peak

* = Impurity peak

** = May contain impurity peak EXAMPLE 4 The calcined portion of the product of Example 3 was ammonium exchanged and calcined at 538°C in air for 16 hours to provide the hydrogen form transformation product of the crystalline MCM-49. The Alpha Test proved this material to have an Alpha Value of 286.

EXAMPLE 5 A 10.5 part quantity of gallium oxide was added to a solution containing 1.0 part sodium aluminate, 3.05 parts 50% NaOH solution and 280 parts H₂0. A 25.6 part quantity of HMI was added followed by 56.6 parts of Ultrasil and 1.7 parts of MCM-22 seeds. The slurry was thoroughly mixed.

The composition of the reaction mixture in mole ratios:

The mixture was crystallized with stirring at 150°C for 10 days. The product was identified as MCM-49 and had the X-ray pattern which appears in Table VII and Figure 3.

The chemical composition of the product was, in wt.%:

N 1.89

Na 0.40 Ga 8.5

A1₂0₃ 0.81

Si0₂ 65.6

Ash 79.3 with silica/alumina and silica/gallia molar ratios for the product of: Si0₂/Al₂0₃ 138 Si0₂/Ga₂0₃ 17.9 The sorption capacities, after calcining for 3 hours at 538"C were, in wt.%: Cyclohexane 13.3

N-Hexane 11.3

H₂0 12.3

A portion of the sample was calcined in air for 16 hours at 538°C. This material exhibited the X-ray diffraction pattern shown in Table VIII.

sh = Shoulder

+ = Non-crystallographic MCM-49 peak

* = Impurity peak

sh = Shoulder

+ = Non-crystal lographic MCM-49 peak * = Impurity peak EXAMPLE 6

The calcined portion of the product of Example 5 was ammonium exchanged and calcined at 538°C in air for 16 hours to provide the hydrogen form transformation product of the crystalline MCM-49. The Alpha Test proved this material to have an Alpha Value of 64.

EXAMPLE 7 A solution containing 1 part of Al (S0.)₃ xH₂0, 1.31 parts of 50% NaOH solution and 14.0 parts of H₂0 was prepared. To this were added 2.8 parts of Ultrasil precipitated silica followed by 1.48 parts of HMI. The reaction mixture was thoroughly mixed. The composition of the reaction mixture in mole ratios was: Si0₂/Al₂0₃ = 25.5 0H~/Si0₂ = 0.15

Na/SiVI. 0₂ = 0.39 HMI/Si0₂ = 0.35 H₂0/Si0₂ = 19.4 The mixture was crystallized for 5 days at 143°C. The product was washed, dried at 120"C and identified by X-ray analysis as MCM-49. It exhibited an X-ray pattern as shown in Table IX and Figure 4.

The sorption capacities, after calcining for 16 hours at 538 |C were, in wt.%:

Cyclohexane 8.8 n-Hexane 15.9 H₂0 13.6

The chemical composition of the product was in wt.%:

N 1.83

Na 0.27

A1₂0₃ 6.8

Si0₂ 73.8

Ash 80.5 The silica/alumina mole ratio of the product was 18.4.

The surface area of this material was measured to

2 be 459 m /g.

A portion of the sample was calcined in air for 16 hours at 538°C. This material exhibited the X-ray diffraction pattern shown in Table X.

sh = Shoulder

+ = Non-crystallographic MCM-49 peak

sh = Shoulder

+ = Non-crystallographic MCM-49 peak

EXAMPLE 8 A 2.24 part quantity of 45% sodium aluminate was added to a solution containing 1.0 part of 50% NaOH solution and 43.0 parts H_?0 in an autoclave. An 8.57 part quantity of Ultrasil precipitated silica was added with agitation, followed by 4.51 parts of HMI.

The reaction mixture had the following composition, in ratios:

Si0₂/Al₂0₃ = 23 OH /Si0₂ = 0.21

Na/S$II. 0₂ = 0.21 HMI/Stll. O = 0.35 H₂0/SiIX. 0₂ = 19.3 The mixture was crystallized at 150°C for 84 hours with stirring. The product was identified as MCM-49 and had the X-ray pattern which appears in Table XI .and Figure 5.

The chemical composition of the product was, in wt.%: N 1.70

Na 0.70

A1_Λ 7.3

Si0₂ 74.5

Ash 84.2 The silica/alumina mole ratio of the product was 17.3.

The sorption capacities, after calcining at 538°C for 9 hours were, in wt.%:

Cyclohexane 10.0 n-Hexane 13.1 H₂0 15.4

A portion of the sample was calcined in air for 3 hours at 538°C. This material exhibited the X-ray diffraction pattern shown in Table XII.

sh = Shoulder

+ = Non-crystallographic MCM-49 peak

* = Impurity peak

sh = Shoulder

+ = Non-crystallographic MCM-49 peak EXAMPLE 9 The calcined portion of the product of Example 8 was ammonium exchanged and calcined at 538°C in air for 3 hours to provide the hydrogen form transformation product of the crystalline MCM-49. The Alpha Test proved this material to have an Alpha Value of 308.

EXAMPLE 10 Synthethic crystalline MCM-49 was prepared by charging 43.0 parts of H O and 1.0 part of NaOH solution (50% by weight) to an autoclave, followed by 2.2 parts of sodium aluminate solution (45% by weight). After mixing thoroughly, 8.6 parts of Nasilco's Ultrasil VN3SP and 4.5 parts of hexamethyleneimine were added and mixed thoroughly. The autoclave was heated to 150°C with stirring and maintained at these conditions until crystallization was complete. The product was identified as MCM-49 by X-ray diffraction. After flashing the hexamethyleneimine, the slurry was cooled, washed, filtered, and dried. MCM-49 composite catalyst was prepared by combining one part of dried

MCM-49 crystalline material with 0.54 part of La Roche Versal brand alumina. The mix was mulled and extruded to form 1/16 inch pellets which were dried at 120°C. The pellets were then calcined in flowing nitrogen for 6 hours at 480°C. The cooled catalyst was exchanged with 1 N NH.NO (5 cc/g catalyst) at room temperature for one hour and then washed with water. The exchange was repeated two more times. The catalyst was then dried at 120"C. The exchange extrudates were calcined in flowing air at 538°C for 12 hours. The calcined material was found to have an Alpha value of 254.

Sorption capacities of the calcined catalyst are shown below in weight percent.

Synthetic crystalline material MCM-22 was prepared by charging 43.5 parts of H,0 and 1.0 part of NaOH solution (50% weight) to an autoclave, followed by 1.7 parts of sodium aluminate solution (45% by weight) . After mixing thoroughly, 8.6 parts of Nasilco's Ultrasil VN3SP and 4.5 parts of hexamethyleneimine were added and mixed thoroughly. The autoclave was heated to 143°C while stirring and was maintained at these conditions until crystallization was complete. The product was identified as MCM-22 by X-ray diffraction. After flashing the hexamethyleneimine, the slurry was cooled, washed, filtered, and dried. MCM-22 composite catalyst was prepared from one part of the dried MCM-22 zeolite crystals and 0.54 part of Kaiser SA alumina. The MCM-22 and alumina mix was mulled and extruded to form 1/16 inch pellets which were dried at 120"C. The extruded pellets were then calcined in flowing nitrogen for 3 hours at 480°C and in air for 6 hours at 538°C. The catalyst was cooled down and exchanged with 1 N NH.NO- at room temperature for two hours. The exchange was repeated two more times and then washed with water. The exchanged extrudates were dried at 120"C and then calcined in flowing air at 538°C for 3 hours.

EXAMPLES 12-17 Examples 12-17 were carried out in a fixed bed reactor using a 50:1 wt. :wt. mixed isobutane:2-butene feed. The activity and product selectivity were monitored by gas chromaographic analysis of the off-gas and liquid product using a fused silica capillary column (Alltech's Durabond DB-1) . The isobutane and olefin feeds (both C.P. Grade) were obtained from Matheson Chemical Company and used without further purification.

The experiments using the MCM-22 catalyst of Example 11 (Examples 15-17) and the MCM-49 catalyst of

Example 10 (Examples 12-14) were conducted at 150"C

(300°F) and 3550 kPa (500 psig) . Both catalysts were crushed to 30/60 mesh size prior to charging to the fixed bed reactor. The weight hourly space velocity (based on catalyst) for Examples 12-17 was 0.045 hr

The data contained in Table XIII and in Figure 7 clearly demonstrate the improvement in catalyst stability shown by the catalyst of the present invention. Table XIII compares the performance of the MCM-49 catalyst with that of the MCM-22 catalyst. The

MCM-49 catalyst showed superior stability while providing comparable product yield and quality to that of MCM-22 catalyst (as measured both by the ratio of high octane trimethylpentanes (TMP) to low octane dimethylhexanes (DMH) and by the Cg yield). (1.8 by the C +yield) . For example at 59 hours on stream (HOS)

(1.8 g C =conv/g catalyst), MCM-49 gave >70%

C =conversion while with MCM-22, at 64 HOS (1.7 g

C4=conv/g catalyst) , the C = conversion dropped to <45%. With MCM-49, ' the C4=conversion was 58% even at

128 HOS (3.9 g C4=conv/g catalyst).

TABLE XIII Fixed-Bed Alkylation: Comparison of Alumina-bound MCM-22 and MCM-49 Catalysts

Catalyst MCM-49/Al₂0₃ MCM-49/Al₂0₃

Reaction Conditions

EX . 12 Ex. 13 Ex. 14 EX . 15 Ex. 16 Ex. 17

Time on Stream (hrs) C =WHSV (hr ) C^=Conv. (wt.%)

10 Grams C. olefin converted per gram of catalyst 0.46 1.83 3.89 0.23 0.59 1.67 C₅+yield, grams C_g+ per gram

15 of olefin converted 1.6 1.7 1.5 1.4 1.6 1.7

C-+Analvsis (weight percent) :

C T ^Co5t^"Ca7l C

Total '8"_rTMP

20 Total DMH

Total Unknown C

225-TMH

V Co_ Composition (weight p

25 TMP DMH Unk C TMP/DMH

Claims

CLAIMS : :

1. An isoparaffin:olefin alkylation process comprising contacting an isoparaffin and an olefin with a synthetic porous crystalline material which is characterized, in its uncalcined form, by an X-ray diffraction pattern including the lines listed in Table 1 below:

TABLE I

Interplanar d-Spacin (A) Relative Intensity, I/Io x 100

13.15 + 0.26 w-s 12.49 + 0.24 vs

11.19 + 0.22 m-s

6.43 + 0.12 w 4.98 ± 0.10 W 4.69 + 0.09 W

3.44 + 0.07 VS _# 3.24 + 0.06 W shoulder.

2. The process of claim 1 wherein said synthetic porous crystalline material has a composition - comprising the molar relationship

X₂0₃:(n)Y0₂, wherein n is less than 35, X is a trivalent element and Y is a tetravalent element.

3. The process of claim 2 wherein x is 15 to less than 20.

4. The process of Claim 2 wherein X comprises aluminum and Y comprises silicon.

5. The process of claim 1 wherein the isoparaffin has from 4 to 8 carbon atoms and the olefin has from 2 to 12 carbon atoms.

6. The process of claim 1 wherein said contacting is effected at a temperature of -20"C to 400°C, a pressure up to 36400 kPa (5000 psig) and a WHSV of 0.01 to 100.

7. The process of claim 1 wherein said contacting is effected at a temperature of -75°C to 200°C, a pressure of 100 to 7000 kPa (atmospheric to 1000 psig) and a WHSV of 0.04 to 10.