Crystalline Zeolite and Method of Preparing Same

1. Field of the Invention

This invention relates to a novel family of crystalline aluminosilicates, to a method for preparation thereof and to use thereof in catalytic conversion of hydrocarbons.

2. Description of the Prior Art

Zeolitic materials, both natural and synthetic, have been demonstrated in the past to have catalytic properties for various type of hydrocarbon conversions. Certain zeolitic materials are ordered, porous crystalline aluminosilicates having a definite crystalline structure within which there are a large number of smaller cavities which may be interconnected by a number of still smaller channels. These cavities and channels are precisely uniform in size. 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 aluminosilicates. These aluminosilicates can be described as a rigid three-dimensional framework of SiO.sub.4 and A1O.sub.4 in which the tetrahedra are cross-linked by the sharing of oxygen atoms whereby the ratio of the total aluminum and silicon atoms to oxygen is 1:2. The electrovalence of the tetrahedra containing 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 aluminum to the number of various cations, such as Ca/2, Sr/2, Na, K or Li is equal to unity. One type of cation may be exchanged either entirely or partially by 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 aluminosilicate 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 aluminosilicates. These aluminosilicates have come to be designated by letter or other convenient symbols, as illustrated by zeolite A (U.S. Pat. No. 2,882,243), zeolite X (U.S. Pat. No. 2,882,244), zeolite Y (U.S. Pat. No. 3,130,007), zeolite ZK-5 (U.S. Pat. No. 3,247,195), zeolite ZK-4 (U.S. Pat. No. 3,314,752) and zeolite ZSM-5 (U.S. Pat. No. 3,702,886), merely to name a few.

One such crystalline aluminosilicate, a rare natural zeolite, is ferrierite. Ferrierite has been described by Graham (Roy, Soc. Canada, Proc. and Trans., 3rd Ser., 12, 185-190) and by Staples (Am. Mineral. 40, 1095-99). The formula of the natural mineral ferrierite is given as (Na, K).sub.4 Mg.sub.2 (Si.sub.30 Al.sub.6) O.sub.72 (OH).sub.2 .18 H.sub.2 O. Barrer and Marshall (Am. Mineral. 50,484-85) in 1965 reexamined the X-ray powder diffraction pattern of a strontium zeolite Sr-D, synthesized by Barrer and Marshall in 1964 (J. Chem. Soc., 485-89) and concluded that it was closely related to natural ferrierite. A synthetic sodium form was briefly described by Senderov (Geokhimiya 9, 820-29) and a Ca-Na form of ferrierite produced by Coombs, Ellis, Fyfe and Taylor (Geochem. Cosmochin. Acta 17, 53-107) was not identified as such.

The present invention relates to a novel family of synthetic ferrierite-type crystalline aluminosilicates, hereinafter designated "zeolite ZSM-21" or simply "ZSM-21", to a method for preparation thereof and to hydrocarbon conversion conducted therewith. The family of ZSM-21 compositions has a characteristic X-ray diffraction pattern, the values of which are set forth in Table 1, hereinafter. The family of ZSM-21 compositions can also be identified, in terms of mole ratios of oxides and in the anhydrous state, as follows:

wherein R is an organic nitrogen-containing cation and M is an alkali metal cation. It will be noticed that the ratio of R.sub.2 O to Al.sub.2 O.sub.3 may exceed unity in this material due to the occlusion of excess organic species (R.sub.2 O) within the zeolite pores.

The ZSM-21 family can further be characterized by its sorptive capacity at 90.degree. C, as will be hereinafter established.

In a preferred synthesized form, the family of zeolite ZSM-21 compositions has a formula, in terms of mole ratios of oxides and in the anhydrous state, as follows:

wherein R is an organic nitrogen-containing cation, especially a cation derived from ethylenediamine, pyrrolidine or 2-(hydroxyalkyl) trialkylammonium compounds, wherein alkyl is methyl, ethyl or a combination of the two, M is an alkali metal, especially sodium, and x is from greater than 8 to about 50.

The present invention further relates to a novel synthetic crystalline aluminosilicate zeolite member of the ZSM-21 family of synthetic ferrierite-type zeolites, hereinafter designated "zeolite ZSM-38" or simply "ZSM-38", to a method for its preparation and to hydrocarbon conversion conducted therewith. The ZSM-38 composition has a characteristic X-ray diffraction pattern, the values of which are set forth in Table 1A, hereinafter. The X-ray pattern values for ZSM-21 are generic to those of ZSM-38 as is demonstrated by comparison of Tables 1 and 1A. The ZSM-38 composition can also be identified, in terms of mole ratios of oxides and in the anhydrous state, as follows:

wherein R is an organic nitrogen-containing cation derived from a 2-(hydroxyalkyl)trialkylammonium compound and M is n alkali metal cation. It will be noticed that the ratio of R.sub.2 O to Al.sub.2 O.sub.3 may exceed unity in this material due to the occlusion of excess organic species (R.sub.2 O) within the zeolite pores.

ZSM-38 can further be characterized by its sorptive capacity at 90.degree. C, as will be hereinafter established.

In a preferred synthesized form, zeolite ZSM-38 has a formula, in terms of mole ratios of oxides and in the anhydrous state, as follows:

wherein R is an organic nitrogen-containing cation derived from a 2-(hydroxyalkyl)trialkylammonium compound, wherein alkyl is methyl, ethyl or a combination thereof, M is an alkali metal, especially sodium, and x is from greater than 8 to about 50.

The original cations of the as synthesized ZSM-21 family of zeolites and, therefor, ZSM-38 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 are those which render the zeolite catalytically active especially for hydrocarbon conversion. These include hydrogen, rare earth metals, aluminum, metals of Groups IIA, IIIB, IVB, VIB, VIII, IB, IIB, IIIA, IVA.

The synthetic ZSM-21 family of zeolites possesses a definite distinguishing crystalline structure whose X-ray diffraction pattern shows substantially the significant lines set forth in Table 1. It is observed that this X-ray diffraction pattern (with respect to significant lines) is similar to that of natural ferrierite with a notable exception being that natural ferrierite patterns exhibit a significant line at 11.33A.

The synthetic ZSM-38 member of the ZSM-21 family of synthetic ferrierite-type zeolites possesses a definite distinguishing crystalline structure whose X-ray diffraction pattern shows substantially the significant lines set forth in Table 1A. Again it is observed that this X-ray diffraction pattern (with respect to significant lines) is similar to that of natural ferrierite with a notable exception being that natural ferrierite patterns exhibit a significant line at 11.33A.

The values of Tables 1 and 1A were determined by standard technique. The radiation was the K-alpha doublet of copper and a scintillation counter spectrometer with a strip chart pen recorder was used. The peak heights, I, and the positions as a function of 2 times theta, where theta is the Bragg angle, were read from the spectrometer chart. From these, the relative intensities, 100 I/Io, where Io is the intensity of the strongest line or peak, and d (obs.), the interplanar spacing in Angstrom units, corresponding to the recorded lines, were calculated. It should be understood that the X-ray diffraction pattern data of Table 1 is characteristic of all the species of ZSM-21 family compositions and the data of Table 1A is characteristic of all species of ZSM-38 compositions. Ion exchange of the sodium ion with cations reveals substantially the same pattern with some minor shifts in interplaner spacing and variation in relative intensity. Other minor variations can occur depending on the silicon to aluminum ratio of the particular sample, as well as if it has previously been subjected to thermal treatment.

A further characteristic of the ZSM-21 family of zeolites and, therefore, ZSM-38 is their sorptive capacity proving said zeolites to have increased capacity for 2-methylpentane (with respect to n-hexane sorption by the ratio n-hexane/2-methylpentane) when compared with a hydrogen form of natural ferrierite resulting from calcination of an ammonium exchanged form. The characteristic sorption ratio n-hexane/2-methylpentane for the ZSM-21 family of zeolites and, therefore, ZSM-38 (after calcination at 600.degree. C) is less than 10, whereas that ratio for the natural ferrierite is substantially greater than 10, for example, as high as 34 or higher.

While synthetic ZSM-21 family zeolites and, therefore, ZSM-38 may be used in a wide variety of hydrocarbon conversion reactions, they are notably useful in the processes of polymerization, aromatization and cracking. Other hydrocarbon conversion processes for which the zeolite compositions of this invention may be utilized in one or more of their active forms include, for example, hydrocracking and converting light aliphatics to aromatics such as in U.S. Pat. No. 3,760,024.

Synthetic ZSM-21 family zeolites and, therefore, ZSM-38 can be used either in the organic nitrogen-containing and alkali metal containing form, the alkali metal form and hydrogen form or another univalent and multivalent cationic form. They can also be used 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 components can be exchanged into the composition, impregnated therein or physically intimately admixed therewith. Such components can be impregnated in or on to the present zeolite compositions, by, for example, in the case of platinum, treating the zeolite with 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. Combinations of metals and methods for their introduction can also be used.

As prepared, R can be one or more of a variety of organic nitrogen-containing cations for the ZSM-21 family of zeolites present in quantity of not less than 40% of the whole, non-limiting examples of which include those cations derived from pyrrolidine, 2-(hydroxyalkyl) trialkylammonium compounds, such as, for example, 2-(hydroxyethyl)trimethylammonium chloride, and ethylenediamine. Non-limiting examples of the 2-hydroxyalkyl) trialkylammonium compounds useful in this invention for R include the halides, e.g., fluorides, chlorides and bromides, the sulfates, the acetates, the nitrates and others. Of course, when the zeolite is ZSM-38 of the ZSM-21 family, as prepared, R is a 2-(hydroxyalkyl)trialkylammonium cation.

Also, M can be one or more of a variety of alkali metal cations, suitably defined as including all alkali metal ions derived from alkali metal oxide or hydroxide as well as alkali metal ions included in alkali metal silicates and aluminates (not including alkali metal salts such as sodium chloride or sodium sulfate which may be derived from neutralization of added inorganic acids such as HCl or H.sub.2 SO.sub.4 or acid salts such as Al.sub.2 (SO.sub.4).sub.3). Non-limiting examples of such suitable alkali metal ions include sodium and potassium.

Synthetic ZSM-21 family zeolites and, therefore, ZSM-38, when employed either as an adsorbent or as a catalyst in a hydrocarbon conversion process, should be dehydrated at least partially. This can be done by heating to a temperature in the range of 200.degree. to 600.degree. C in an inert atmosphere, such as air, nitrogen, etc. and at atmospheric or subatmospheric pressure for between 1 and 48 hours. Dehydration can also be performed at lower temperature merely by placing the catalyst in a vacuum, but a longer time is required to obtain a sufficient amount of dehydration.

Zeolites of the present invention can be suitably prepared by preparing a solution containing sources of an alkali metal oxide, preferably sodium oxide, an organic nitrogen-containing oxide, an oxide of aluminum, an oxide of silicon and water and having a composition, in terms of mole ratios of oxides, falling within the following ranges:

wherein R is an organic nitrogen-containing cation derived from ethylenediamine, pyrrolidine or, in the case of ZSM-38, from a 2-(hydroxyalkyl)trialkylammonium compound, and M is an alkali metal ion, and maintaining the mixture until crystals of the zeolite are formed. The quantity of OH.sup.- in the above ranges is calculated only from the inorganic sources of alkali without any organic base contribution. Thereafter, the crystals are separated from the liquid and recovered. Typical reaction conditions consist of heating the foregoing reaction mixture to a temperature of from about 90.degree. to about 400.degree. F for a period of time of from about 6 hours to about 100 days. A more preferred temperature range is from about 150.degree. to about 400.degree. F with the amount of time at a temperature in such range being from about 6 hours to about 80 days.

The digestion of the gel particles is carried out until crystals form. The solid product is separated from the reaction medium, as by cooling the whole to room temperature, filtering and water washing.

The crystalline product is dried, e.g. at 230.degree. F, for from about 8 to 24 hours. Of course, milder conditions may be employed if desired, e.g. room temperature under vacuum.

The composition for the synthesis of synthetic ZSM-21 family zeolites and, therefore, ZSM-38 can be prepared utilizing materials which can supply the appropriate oxide. Such compositions include aluminates, alumina, silicates, silica hydrosol, silica gel, silicic acid and hydroxides. It will be understood that each oxide component utilized in the reaction mixture for preparing the present zeolites can be supplied by one or more essential reactants and they can be mixed together in any order. For example, any oxide can be supplied by an aqueous solution, sodium hydroxide or by an aqueous solution of a suitable silicate; the organic nitrogen-containing cation can be supplied by a compound of that cation, such as, for example, the hydroxide or a salt, as well as by the indicated amines. The reaction mixture can be prepared either batchwise or continuously. Crystal size and crystallization time of the zeolte composition will vary with the nature of the reaction mixture employed.

FIG. 1 is a photographically reduced copy of the actual X-ray powder diffraction pattern tracing of the crystalline aluminosilicate zeolite ZSM-38 prepared in Example 1, hereinafter presented.

FIG. 2 is a photographically reduced copy of the actual X-ray powder diffraction pattern tracing of the crystalline aluminosilicate zeolite ZSM-38 prepared in Example 2, hereinafter presented.

FIG. 3 is a photographically reduced copy of the actual X-ray powder diffraction pattern tracing of the crystalline aluminosilicate zeolite member of the ZSM-21 family prepared in Example 7, hereinafter presented.

FIG. 4 is a photographically reduced copy of the actual X-ray powder diffraction pattern tracing of the crystalline aluminosilicate zeolite member of the ZSM-21 family prepared in Example 24, hereinafter presented.

The numbers on the bottom scale of the figures indicate degrees 2 theta.

Synthetic zeolites of the ZSM-21 family and, therefore, ZSM-38 can have the original cations associated therewith replaced by a wide variety of other cations according to techniques well known in the art. Typical replacing cations include hydrogen, ammonium and metal cations including mixtures thereof. Of the replacing metallic cations, particular preference is given to cations of metals such as rare earth, Mn, Ca, Mg, Zn, Cd, Pt, Pd, Ni, Co, Ti, Al, Sn, Fe and Co.

Typical ion exchange techniques would be to contact the synthetic zeolite with a salt of the desired replacing cation or cations. Although a wide variety of salts can be employed, particular preference is given to chlorides, nitrates and sulfates.

Representative ion exchange techniques are disclosed in a wide variety of patents including U.S. Pat. Nos. 3,140,249; 3,140,251; and 3,140,253.

Following contact with the salt solution of the desired replacing cation, the zeolite is then preferably washed with water and dried at a temperature ranging from 150.degree. F to about 600.degree. F and thereafter may be calcined in air or other inert gas at temperatures ranging from about 500.degree. to 1500.degree. F for periods of time ranging from 1 to 48 hours or more to produce a catalytically-active thermal decomposition product thereof.

Regardless of the cations replacing the alkali metal in the synthesized form of the zeolite, the spatial arrangement of the aluminum, silicon and oxygen atom which form the basic crystal lattices of the zeolite remains essentially unchanged by the described replacement of alkali metal as determined by taking an X-ray powder diffraction pattern of the ion-exchanged material.

The alumiosilicate prepared by the instant invention is formed in a wide variety of particle sizes. Generally speaking, the particles can be in the form of a powder, a granule, or a molded product, such as extrudate having particle size sufficient to pass through a 2 mesh (Tyler) screen and be retained on a 400 mesh (Tyler) screen. In cases where the catalyst is molded, such as by extrusion, the aluminosilicate can be extruded before drying or dried or partially dried and then extruded.

In the case of many catalysts, it is desired to incorporate the zeolite of the ZSM-21 family, and therefore, ZSM-38 with another material resistant to the temperatures and other conditions employed in organic conversion processes. Such matrix 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. The latter may be either naturally occurring or in the form of gelatinous precipitates, sols or gels including mixtures of silica and metal oxides. Use of a material in conjunction with the synthetic zeolite i.e. combined therewith, which is active, tends to improve 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. Frequently, zeolite materials have been incorporated into naturally occurring clays, e.g. bentonite and kaolin. These materials, i.e. clays, oxides, etc., function, in part, as binders for the catalyst. It is desirable to provide a catalyst having good crush strength, because in a petroleum refinery the catalyst is often subjected to rough handling, which tends to break the catalyst down into powder-like materials which cause problems in processing.

Naturally occurring clays which can be composited with the synthetic zeolites of this invention include the montmorillonite and kaolin family, which families include the sub-bentonites, and the kaolins commonly known as Dixie, McNamee, Georgia and Florida clays or others in which the main mineral constituents 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.

In addition to the foregoing materials, the ZSM-21 family of zeolites and, therefore, ZSM-38 can be composited with a porous matrix material such as silica-alumina, silica-magnesia, silica-zirconia, silica-thoria, silica-beryllia, silica-titania, titania-zirconia as well as ternary compositions such as silica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesia and silica-magnesia-zirconia. The matrix can be in the form of a cogel. A mixture of these components could also be used. The relative proportions of finely divided crystalline aluminosilicate zeolite of this invention and inorganic oxide gel matrix vary widely with the crystalline aluminosilicate content ranging from about 1 to about 90 percent by weight and more usually in the range of about 2 to about 50 percent by weight of the composite.

In employing the zeolite catalyst of this invention for polymerization of olefin-containing liquid or gaseous charge stocks, such charge stocks can be polymerized at temperatures between 550.degree. and 850.degree. F at an hourly space velocity of between 0.5 and 50 WHSV and a pressure between 0.1 and 800 psig.

In employing the catalyst of the present invention for aromatization of gaseous or liquid charge stocks which may be olefinic or paraffinic with or without aromatics present, such stocks can be aromatized at temperatures between 800 and 1200.degree. F and pressures from 1 to 10 atmospheres and space velocities between 0.1 and 10 WHSV.

In order to more fully illustrate the nature of the invention and the manner of practicing same, the following examples are presented.

In the examples which follow, whenever adsorption data are set forth for comparison of sorptive capacities for water, cyclohexane and n-hexane, they were determined as follows:

A weighed sample of the calcined zeolite was contacted with the desired pure adsorbate vapor in an adsorption chamber, evacuated to 12 mm when checking capacity for water and 20 mm when checking capacity for cyclohexane and n-hexane, pressures less than the vapor-liquid equilibrium pressure of the respective adsorbate at room temperature. 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 eight hours. As adsorbate was adsorbed by the zeolite, 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.

When the sorptive capacities for 2-methylpentane and n-hexane were measured for distinguishing comparisons of ratios of n-hexane/2-methylpentane sorption, a weighed sample of zeolite was heated to 600.degree. C and held at that temperature until the evolution of basic nitrogenous gases ceased. The zeolite was then cooled and the sorption test run essentially as above with the sorption being conducted at 90.degree. C and the sorbate being chilled at 0.degree. C.

Illustrating a preparation of a synthetic zeolite of the ZSM-21 family of zeolites, i.e. ZSM-38, a first solution was prepared comprising 34.4g sodium silicate (28.8% SiO.sub.2, 8.9% Na.sub.2 O and 62.2% H.sub.2 O), 2.4g sodium aluminate (44.7% Al.sub.2 O.sub.3, 31.3% Na.sub.2 O and 24.0% H.sub.2 O), 9.7g NaOH and 76.4g water. A second solution was prepared by first mixing 23.74g Al.sub.2 (SO.sub.4).sub.3 .14 H.sub.2 O, 12.5g H.sub.2 SO.sub.4 and 75.0g water and then adding to that mixture 135.0g of the sodium silicate. At this point, the second solution was added to the first solution to provide a gel which was mixed until homogeneous and aged at 99.degree. C for 1-2 hours. The solid which formed was filtered out and the filtrate was discarded. A third solution, made up of 18.72g of 2-(hydroxyethyl) trimethylammonium chloride, 10.0g of 10% NaOH solution and 20.0g water, was then added to the above solid and the resulting mixture was mixed until homogeneous and crystallized (99.degree. C for 83 days).

The crystallization mixture was comprised of the following components in mole ratios:

The crystalline product was filter separated, water washed and X-ray analyzed. The X-ray analysis showed the crystalline product of this example to have the diffraction pattern shown below:

A photographically reduced exact copy of the actual X-ray diffraction pattern of the ZSM-38 product of Example 1 is shown in FIG. 1 of the drawings.

Chemical analysis of the product of this example provided the following compositional figures:

Physical analysis of the product of this example indicated that the surface area of the crystals after calcination at 1000.degree. F for 16 hours was 372 m.sup.2 /g. Adsorption tests provided the following data:

In another illustration of the preparation of a ZSM-21 family zeolite, i.e. ZSM-38, a first solution was prepared comprising 103.2g sodium silicate (as defined in Example 1), 7.2g sodium aluminate (as defined in Example 1), 29.1g sodium hydroxide and 229.2g water. A second solution was prepared by first mixing 71.22g Al.sub.2 (SO.sub.4).sub.3.14 H.sub.2 O, 37.5g H.sub.2 SO.sub.4 and 225g water and then adding to that mixture 405g of the sodium silicate. The second solution was then added to the first solution and the resultant gel was mixed until homogeneous and aged at 99.degree. C for 1-2 hours. The solid which formed was then filtered out of solution and the filtrate was discarded. A third solution, made up of 56.2g 2-(hydroxyethyl) trimethylammonium chloride, 30.0g of 10% sodium hydroxide solution and 60.0g water, was then added to the above solid and the resulting mixture was mixed until homogeneous and crystallized (99.degree. C for 70 days).

The crystallization mixture was comprised of the following components in mole ratios:

The crystalline product was filter separated, water washed and X-ray analyzed. The X-ray analysis showed the crystalline product of this example to have the diffraction pattern of Table 1A. A photographically reduced copy of the actual X-ray powder diffraction pattern from the zeolite ZSM-38 product of Example 2 is shown in FIG. 2 of the drawings.

Chemical analysis of the product of this example provided the following compositional figures:

Physical analysis of the product of this example calcined 16 hours at 1000.degree. F indicated that the surface area of the crystals was 403 m.sup.2 /g. Adsorption tests provided the following data:

Another illustration of the preparation of a ZSM-21 family zeolite, i.e., ZSM-38, follows with first, second, and third solutions being prepared and mixed according to those of Example 2. The final product crystallization, however, was produced by holding the crystallizing liquid at 99.degree. C for 78 days. X-ray analysis showed the crystalline product to have the diffraction pattern shown in Table 1A, and adsorption tests demonstrated the following properties:

The product crystalline zeolite ZSM-38 of Example 2 was calcined at 1000.degree. F for 10 hours and exchanged with ammonium chloride solution to yield an ammonium exchanged ZSM-38 product. The exchanged zeolite was then dried at 230.degree. F for 16 hours and calcined at 1000.degree. F for 10 hours to give the hydrogen form of the ZSM-38 zeolite (HZSM-38).

This HZSM-38 then was used as a catalyst in a polymerization reaction as hereinbefore generally described utilizing propylene as the feed with a reaction temperature of 600.degree. F, reaction pressure of one atmosphere and space velocity of 0.98. The propylene feed was converted to liquid product at conversion of 88.1 weight percent with a product composition of C.sub.4 -C.sub.11 olefinic compounds having a clear research octane number of 95 (motor octane number 81) and a density of 0.72g/cc. The refractive index of the reaction product was 1.4173.

The HZSM-38 zeolite of Example 4 was also used as a catalyst in an aromatization reaction as hereinbefore generally described utilizing propylene as the feed with a reaction temperature of 1100.degree. F, reaction pressure of one atmosphere and space velocity of 3.48. The propylene feed was converted to liquid product comprising predominantly aromatic mixtures at a conversion of approximately 5.1 weight percent of liquid product have a clear research octane number of 110 (motor octane number of 91) and a density of 0.87g/cc. The refractive index of the reaction product was 1.48.

A quantity of natural ferrierite with a mole ratio of SiO.sub.2 to Al.sub.2 O.sub.3 of 12 was ammonium exchanged and calcined as in Example 4. A batch of the H-ferrierite product was subjected to the aforementioned sorption test for measuring the distinctive sorption capacity ratio of n-hexane/2-methylpentane at 90.degree. C. Results of that test showed sorption of 3.4 weight percent n-hexane and less than 0.1 weight percent 2-methylpentane (n-hexane/2-methylpentane = > 34).

Illustrating preparation of another synthetic zeolite ZSM-21 family member, a first solution comprising 3.3g sodium aluminate (41.8% Al.sub.2 O.sub.3, 31.6% Na.sub.2 O and 24.9% H.sub.2 O), 87.0g H.sub.2 O and 0.34 NaOH (50% solution with water) was prepared. The organic material pyrrolidine was added to the first solution in 18.2g quantity to form a second solution. Thereupon, 82.4g colloidal silica (29.5% SiO.sub.2 and 70.5% H.sub.2 O) was added to the second solution and mixed until a homogeneous gel was formed. This gel was composed of the following components in mole ratios:

The mixture was maintained at 276.degree. F for 17 days, during which time crystallization was complete. The product crystals were filtered out of solution and water washed for approximately 16 hours on continuous wash line.

X-ray analysis of the crystalline product proved the crystals to have a diffraction pattern within the confines of that shown in Table 1. A photographically reduced exact copy of the X-ray powder diffraction pattern tracing for the zeolite product of this example is shown in FIG. 3 of the drawings.

Chemical analysis of the crystalline product led to the following compositional figures:

Physical analysis of the crystalline product of Example 7 calcined 16 hours at 1000.degree. F showed it to have a surface area of 304 m.sup.2 /g and adsorption tests (conducted as hereinbefore described) produced the following results:

A batch of another member of the ZSM-21 family of zeolites was prepared by first making a solution of 101.6g sodium silicate (28.8% SiO.sub.2, 8.9% Na.sub.2 O and 62.2% H.sub.2 O), 6.5g NaOH (50% solution) and 59.8g H.sub.2 O. Then 30.0g ethylenediamine was added to the first solution. To this mixture was added a solution comprised of 19.4g Al.sub.2 (SO.sub.4).sub.3.18H.sub.2 O, 4.5g H.sub.2 SO.sub.4 and 174g H.sub.2 O, and the resultant gel was mixed until homogeneous. This gel was composed of the following components in mole ratios:

The gel mixture was maintained at 210.degree. F for 62 days, during which time crystallization was complete. The product crystals were filtered out of solution and water washed.

X-ray analysis of the crystalline product proved the crystals to have a diffraction pattern within the confines of that shown in Table 1 and chemical analysis proved them to have a mole ratio of SiO.sub.2 to Al.sub.2 O.sub.3 of 14.4

In the aforementioned sorption test for measuring the distinctive sorption capacity ratio of n-hexane/2-methylpentae at 90.degree. C, the sample of ZSM-21 prepared according to this example sorbed 5.1 weight percent n-hexane and 2.8 weight percent 2-methylpentane (n-hexane/2-methylpentane = 1.82).

A quantity of the zeolite product of Example 8 was processed as in Example 4 to produce an HZSM-21 zeolite.

A quantity of H-ferrierite prepared as in Example 6 and the HZSM-21 product of Example 9 were subjected to a modified version of the alpha-test described by P. B. Weisz and J. N. Miale in Journal of Catalysis, 4, 527-529 (1965) to determine cracking rate of n-hexane with the liquid hourly space velocity maintained at 1.0 and the temperature maintained at 800.degree. F. The alpha-test of this example differs from that described by Weisz and Miale only in that the feed here is a mixture of n-hexane, 3-methyl pentane and 2,2-dimethylbutane. The results, indicating vast superiority of HZSM-21 in comparison with H-ferrierite in cracking activity, were as follows:

Further examples are presented by way of tabular accumulation of data as follows in Tables 2, 2A, 3, 3A, 4 and 4A. Tables 2 and 2A show examples of preparation of the ZSM-38 member of the ZSM-21 family of zeolites, while using 2-(hydroxyethyl) trimethylammonium chloride as the source of organic nitrogen-containing cation. In each example presented by way of Tables 2 and 2A, R is [(CH.sub.3).sub.3 -N-CH.sub.2 -CH.sub.2 OH] and M is sodium. X-ray analysis of the products of each of the examples presented by Tables 2 and 2A proved them to have a diffraction pattern as shown in Table 1A.

Tables 3 and 3A show examples of ZSM-21 family zeolite preparation while using pyrrolidine as the source of organic nitrogen-containing cation. In each example of Tables 3 and 3A, R.sup.+ is the pyrrolidine ion and M is sodium.

Tables 4 and 4A show examples of ZSM-21 family zeolite preparation while using ethylenediamine as the organic nitrogen-containing cation source, wherein R is [H.sub.2 N(CH.sub.2).sub.2 NH] and M is sodium.

X-ray analysis of the products of each of the examples presented in Tables 3, 3A, 4 and 4A proved them to have a diffraction pattern within the confines of that shown in Table 1.