DE2749024C2 - Crystalline aluminosilicate zeolites, processes for their preparation and their use - Google Patents

Description

The invention relates to a new crystalline aluminosilicate zeolite, to processes for its preparation and to its use as a catalyst in a variety of transformations of organic compounds.

Well-known zeolites, sometimes referred to as "molecular sieves", include a variety of positive ion-containing crystalline aluminosilicates, both natural and synthetic. Synthetic zeolites include A, Y, L, D, R, S, T, Z, E, F, Q, B, X; erionite and offretite are well-known natural zeolites. All can be described as a rigid three-dimensional lattice of SiO[deep]4 and AlO[deep]4, in which the tetrahedra are linked by shared oxygen atoms, so that the ratio of total aluminum and silicon atoms to oxygen atoms is 1:2. The charge of the aluminum-containing tetrahedra is negative and the composition is balanced by the inclusion of the cation in the crystal structure, for example an alkali metal or an alkaline earth metal cation. The spaces between the tetrahedra are occupied by water molecules before dehydration: it is common to dehydrate zeolites before their use as sorbents or catalysts.

According to the invention, a new crystalline aluminosilicate zeolite, a ZSM-34, has the following composition (in molar ratios of oxides):

M[deep](2/n)O : Al[deep]2O[deep]3 : (8-50) SiO[deep]2

where M is a cation of valence n and is alkali metal, alkaline earth metal, hydrogen, hydrogen precursors, metals of groups IB, II, III, VIIB, VIII (corresponds to groups 1B, 2, 3, 7A, 8 according to IVPAC Rule 1.21) or rare earth metals, having a powder X-ray diffraction pattern as given in Table I and a sorption capacity after firing at 538°C for n-hexane at room temperature and an n-hexane pressure of 20 mm of at least 9.5 wt.%.

The SiO[deep]2/Al[deep]2O[deep]3 molar ratio is preferably 8 to 30, particularly preferably 8 to 20.

In contrast, the zeolite in the anhydrous form as synthesized has the following composition (in molar ratios of oxides):

(0.5-1.3) R[deep]2O: (0-0.15) Na[deep]2O: (0.1-0.5) K[deep]2O: Al[deep]2O[deep ]3 : (8-50) SiO[deep]2,

where R is an organic nitrogen-containing cation derived from choline. The formula given for the synthesized form of the zeolite clearly indicates a larger cation/aluminium equivalent than the unit required by structural considerations. This is because chemical analysis of the zeolites in the synthesized form rarely gives the complete cation/aluminium equivalent, especially when nitrogen-containing cations play a role in the synthesis: The general formula given here first, in which cations are designated by M, is, on the other hand, the ideal formula.

According to a further aspect of the invention, a process for producing a crystalline

Aluminosilicate zeolites involve the formation of a mixture containing sodium oxide, potassium oxide, silicon dioxide, alumina, a choline compound and water and having a composition in molar ratios of oxides within the following ranges:

SiO[deep]2/Al[deep]2O[deep]3 10-70

OH[high]-/SiO[low]2 0.3-1.0

H[low]2O/OH[high]- 20-100

K[deep]2O/M[deep]2O 0.1-1.0

R[high]+/R[high]+ + M[high]+ 0.1-0.8

where R[high]+ choline and M is sodium + potassium, heating the mixture to a temperature between 80 and 175°C for a period of 12 hours to 200 days until zeolite crystals form. The zeolite crystals formed are filtered off, washed with water, dried and optionally fired at temperatures of 200 to 750°C and subjected to an ion exchange treatment.

The mixture advantageously has a composition within the following ranges:

SiO[deep]2/Al[deep]2O[deep]3 10-55

OH[high]-/SiO[low]2 0.3-0.8

H[low]2O/OH[high]- 20-80

K[deep]2O/M[deep]2O 0.1-1.0

R[high]+/R[high]+ + M[high]+ 0.1-0.50

The invention further relates to a process for converting an organic material, in which the organic material is contacted under conversion conditions with a catalyst containing zeolite ZSM-34. Conversions which are particularly effectively carried out with respect to hydrocarbon materials include cracking and polymerization.

A particularly effective conversion of a non-hydrocarbon material is the conversion of methanol and/or dimethyl ether to a hydrocarbon product rich in ethylene and propylene, the conversion conditions being a temperature between 260 and 538°C (500 and 1000°F), a pressure of 0.1 to 30 atmospheres, and a weight hourly space velocity between 0.1 and 30. In this embodiment, ethylene and propylene may constitute the major portion of the hydrocarbon reaction product, with the ethylene content of the product often exceeding the propylene content. Typically, the amount of ethylene and propylene formed exceeds 35 weight percent, and the amount of methane formed is not more than 10 weight percent of the hydrocarbon reaction product.

Whatever the nature of the conversion, the zeolite is preferably thermally treated at a temperature of 200 to 750°C prior to use, and at least 10% of its cation sites are preferably occupied by ions other than alkali or alkaline earth metals. Suitable replacing cations are hydrogen, hydrogen precursors, metals of Groups IB, II, III, VIIB, VIII or rare earth metals, of which hydrogen and/or rare earth are particularly preferred. Advantageously, the catalyst may be composed of the zeolite with a porous matrix. In addition, in some applications, the zeolite benefits from prior steam treatment for 1 to 100 hours at 371 to 649°C (700 to 1200°F).

ZSM-34 is similar in some respects to offretite or erionite, but differs from these zeolites in its ability to sorb at least 9.5 weight percent n-hexane at room temperature and an n-hexane pressure of 20 mm after firing at 538°C (1000°F) for at least a time sufficient to remove any organic cation, which is more than any known member of the offretite-erionite group. ZSM-34 is further characterized by an obvious tabular structure, and its X-ray diffraction pattern shows the following characteristic lines:

Table I

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°2 big theta D (Angstrom) Relative intensity

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7.68 11.5 +/- 0.2 very strong

9.62 9.2 +/- 0.2 weak

11.67 7.58 +/- 0.15 medium

13.39 6.61 +/- 0.13 strong

14.01 6.32 +/- 0.12 weak

15.46 5.73 +/- 0.11 medium

16.57 5.35 +/- 0.10 weak

17.81 4.98 +/- 0.10 weak

19.42 4.57 +/- 0.09 strong - very strong

20.56 4.32 +/- 0.08 very strong

21.36 4.16 +/- 0.08 weak

23.35 3.81 +/- 0.07 strong - very strong

23.79 3.74 +/- 0.07 very strong

24.80 3.59 +/- 0.07 strong - very strong

27.02 3.30 +/- 0.06 medium - strong

28.33 3.15 +/- 0.06 medium

30.62 2.92 +/- 0.05 weak

31.41 2.85 +/- 0.05 very strong

31.93 2.80 +/- 0.05 weak

33.50 2.67 +/- 0.05 weak

35.68 2.52 +/- 0.05 weak

36.15 2.48 +/- 0.05 weak - medium

38.30 2.35 +/- 0.04 weak

39.49 2.28 +/- 0.04 weak

These values were determined by standard techniques. The radiation was the K[deep]small alpha doublet of copper, and a scintillation counting spectrometer with a strip chart recorder was used. The peak heights I and position as a function of 2 major theta, where major theta is the Bragg angle, were read from the spectrometer strip. From these the relative intensities 100 I/I[deep]0, where I[deep]0 is the intensity of the strongest line or peak and d (obs.) is the interplanar spacing in angstroms, were calculated corresponding to the chart recorder lines. The intensity in the above table is expressed as follows:

_____________________________________________________________________________

Relative intensity 100 I/I[deep]0

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Very strong 60-100

strong 40-60

medium 20-40

weak 0-20

ZSM-34 shows "l" odd or redundant lines which would not be expected if it had the open offretite structure. These "1" odd lines (at about 9.6, 16.6, 21.4 and 31.9° 2 major theta) are broad as opposed to sharp in erionite. Without being constrained by any theory, these data can be taken to indicate that ZSM-34 is not a physical mixture of offretite and erionite, but rather an intergrowth of very small erionite regions throughout an offretite structure. These erionite regions appear as a multitude of defects and may contribute to blockages of the main offretite channel.

Zeolite T was described by Bennett and Gard, Nature 214, 1005 (1967) as a disordered intergrowth of erionite and offretite. Although the X-ray diffraction pattern of ZSM-34 indicates it as an intergrowth of offretite and erionite, ZSM-34 differs from zeolite T. As shown in Table II below, ZSM-34 shows a line at 14.01° 2 theta and the "l" odd lines at about 16.62 and 31.92° 2 theta, which are absent in zeolite T. The latter, on the other hand, shows some faint lines at about 14.74, 21.78, 24.28° 2 theta and a doublet at about 31.2° 2 theta.

A comparison of the X-ray diffraction patterns of ZSM-34, offretite, erionite and zeolite T is shown below.

Table II

The equilibrium adsorption properties of ZSM-34 are compared with those of representatives of the offretite-erionite group in Table III below.

Table III

The above adsorption data were determined as follows:

A weighed sample of the zeolite was contacted with the desired pure adsorbate vapor in the adsorption chamber at a pressure below the vapor-liquid equilibrium pressure of the adsorbate at room temperature, e.g. about 25°C. This pressure was kept constant during the adsorption period, which did not exceed 8 hours. Adsorption was complete when a constant pressure was reached in the adsorption chamber, i.e. 12 mm Hg for water and 20 mm for n-hexane and cyclohexane. The weight gain was calculated as the adsorption capacity of the sample.

From the data tabulated above, it can be seen that ZSM-34 was characterized by the highest sorption capacity for water and n-hexane. A unique property of ZSM-34 is that, in contrast to other known representatives of the offretite-erionite group, this zeolite has the ability to sorb at least 9.5 weight percent of n-hexane.

The original cations of ZSM-34 can be at least partially replaced by ion exchange with other cations, preferably after firing, according to techniques well known in the art. Preferred replacing cations are tetraalkylammonium cations, metal ions, ammonium ions, hydrogen ions and mixtures thereof. Particularly preferred cations are those which render the zeolite catalytically active, particularly for hydrocarbon conversion. These include hydrogen, rare earth metals, aluminum, manganese and metals of Groups II and VIII of the Periodic Table.

ZSM-34 can be conveniently synthesized by preparing a gel reaction mixture of a composition in molar ratios of oxides within the following ranges:

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Widely Preferred

_____________________________________________________________________________________

SiO[deep]2/Al[deep]2O[deep]3 10 - 70 10 - 55

OH[high]-/SiO[low]2 0.3 - 1.0 0.3 - 0.8

H[low]2O/OH[high]- 20 - 100 20 - 80

K[deep]2O/M[deep]2O 0.1 - 1.0 0.1 - 1.0

R[high]+/R[high]+ + M[high]+ 0.1 - 0.8 0.1 - 0.50

where R[high]+ is choline [(CH[low]3)[low]3 x N-CH[low]2CH[low]2OH] and M is Na + K and the mixture is maintained until zeolite crystals form. OH[high]- is calculated from inorganic base, not neutralized by any addition of a mineral acid or acid salt. The resulting zeolite crystals are separated and recovered. Typical reaction conditions consist of heating the above reaction mixture to a temperature of 80 to 175°C for a time of 12 hours to 200 days. A more preferred temperature range is between about 90 and 160°C, with the time being between about 12 hours and 50 days.

The resulting crystalline product is filtered from the mother liquor, washed with water and dried, e.g., for 4 to 48 hours at 110°C (230°F). If desired, milder conditions can be used, e.g., room temperature under vacuum.

When ZSM-34 is used either as an adsorbent or as a catalyst in a hydrocarbon conversion process, it should be at least partially dehydrated and the organic cation at least partially removed. This can be done by heating to a temperature in the range of 200 to 750°C in an atmosphere such as air, nitrogen, etc. and at atmospheric or sub-atmospheric pressure for between 1 and 48 hours. Pre-dehydration can also be done at lower temperatures by merely placing the catalyst in a vacuum, but more time is required to achieve adequate dehydration.

The starting agent for the ZSM-34 can be prepared using materials that provide the appropriate oxide. Such agents include sodium aluminate, alumina, sodium silicate, silica hydrosol, silica gel, silica, sodium hydroxide, aluminum sulfate, potassium hydroxide, potassium silicate, and a choline compound such as the halide, i.e., fluoride, chloride or bromide; sulfate, acetate or nitrate. Of course, each oxide component employed in the reaction mixture to prepare ZSM-34 can be supplied by one or more original reaction components, and they can be mixed together in any order. The reaction mixture can be prepared either batchwise or continuously. Crystal size and crystallization time of the ZSM-34 mass will vary with the type of reaction mixture used.

In many cases it is desirable to admix the ZSM-34 with another material which is resistant to the temperature and other conditions employed in organic conversion processes. Such materials include active and inactive materials and synthetic or naturally occurring zeolites such 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 or gels including mixtures of silica and metal oxides. The use of an active material in conjunction with, i.e. combined with, ZSM-34 results in improving the conversion and/or selectivity of the catalyst in certain organic conversion processes. Inactive materials suitably serve as diluents to control the degree of conversion in a given process so that products can be obtained economically and methodically without further measures to control the reaction rate. Typically, zeolite materials have been admixed with naturally occurring clays, e.g. B. Bentonite and kaolin, are incorporated to improve the attrition resistance of the catalyst under industrial working conditions. These materials, i.e. clays, oxides and the like, act as binders for the catalyst. A catalyst with good attrition resistance is desired because in a petroleum refinery the catalyst is often subjected to rough handling which leads to the catalyst breaking apart into powder-like materials, causing processing problems. These clay binders are used to improve the attrition resistance of the

catalyst was used.

Naturally occurring clays which can be contacted with the ZSM-34 catalyst are those of the montmorillonite and kaolin groups, which include the subbentonites and the kaolins commonly referred to as Dixie, McNamee Georgia and Florida clays, or others in which the principal mineral constituent is halloysite, kaolinite, dickite, nacrite or anauxite. Such clays may be used in the raw state as originally mined or initially calcined, acid treated or chemically modified.

In addition to the above materials, ZSM-34 can be blended with a porous matrix material such as silica/alumina, silica/magnesia, silica/zirconia, silica/thoria, silica/beryllia, silica/titania, and ternary blends such as silica/alumina/thoria, silica/alumina/zirconia, silica/alumina/magnesia, silica/magnesia/zirconia. The matrix can be in the form of a cogel. The relative ratio of finely divided ZSM-34 to inorganic oxide gel matrix can vary widely, with the content of crystalline aluminosilicate ranging from about 1 to about 90 percent by weight, and more usually from about 2 to about 50 percent by weight of the composition.

As mentioned above, ZSM-34 is useful as a catalyst in organic compound conversions. Representative hydrocarbon conversions are cracking, hydrocracking, alkylation, isomerization of n-paraffin and naphthenes, polymerization of compounds containing an olefinic or acetylenic C-C bond such as propylene, isobutylene and butene-1, reforming, isomerization of polyalkyl substituted aromatics, e.g., o-xylene, and disproportionation of aromatics such as toluene to a mixture of benzene, xylenes and higher methylbenzenes. The ZSM-34 catalysts are characterized by high selectivity under the hydrocarbon conversion conditions and provide a high percentage of the desired products.

ZSM-34 is generally used in the ammonium, hydrogen or monovalent or polyvalent cationic form. It may also be used in intimate admixture with a hydrogenating component such as 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. Such a component may be introduced into the zeolite by exchange, applied thereto by impregnation or intimately physically mixed therewith.

When the ZSM-34 catalyst of the invention is used for cracking, hydrocarbon feedstocks can be cracked at a liquid hourly space flow rate of between about 0.5 and 50, a temperature of between 288 and 593°C (550 and 1100°F), and a pressure of between about atmospheric and several hundred atm. When used to polymerize olefins, the temperature is between about 288 and 454°C (550 and 850°F) using a weight hourly space flow rate of between about 0.1 and about 30 and a pressure of between about 0.1 and about 50 atm.

In accordance with a particularly preferred embodiment of the invention, it has been found that the use of ZSM-34 as catalyst provides a substantially higher selectivity of the formation of ethylene and propylene from methanol and/or dimethyl ether than when using other crystalline aluminosilicate zeolites. It has also been found that when using the particular crystalline aluminosilicate zeolite catalyst as described herein, the C[low]2-C[low]3 olefin content of the resulting reaction product can be in excess of 35 weight percent and preferably represents a major portion of such reaction product. This is substantially free of aromatic hydrocarbons and, as a result of the use of the particular catalyst, contains less than 20 weight percent and preferably not more than 10 weight percent methane.

The methanol feedstock can be produced from synthesis gas, i.e. a mixture of CO and H[low]2, from coal or by fermentation.

In the ZSM-34 used in this embodiment, preferably at least 10% of the cation sites are occupied by ions other than alkali or alkaline earth metal ions. Replacement of the original ions is generally accomplished by ion exchange, preferably after firing. Typical, but not limiting, replacement ions are ammonium, hydrogen, rare earth, zinc, copper, nickel and aluminum. Of these, particularly preferred are ammonium, hydrogen, rare earth or combinations thereof. In a preferred embodiment, the zeolites are converted predominantly to the hydrogen form, generally by replacing the alkali metal or other ion originally present with a hydrogen ion precursor, e.g., ammonium ions, which upon firing yield the hydrogen form. This replacement is conveniently accomplished by contacting the zeolite with an ammonium salt solution, e.g., ammonium chloride, using well-known ion exchange techniques. The extent of replacement is such as to form a zeolite material in which at least 50% of the cation sites are occupied by hydrogen ions.

Occasionally it has been found desirable to subject the ion-exchanged zeolite to a steam treatment for about 1 to 100 hours at a temperature above about 371°C (700°F) but below about 649°C (1200°F).

The methyl alcohol and/or dimethyl ether conversion is typically carried out in the vapor phase by contact in a reaction zone, such as a fixed catalyst bed, under effective conversion conditions. Such conditions include an operating temperature between about 260 and about 538°C (500 and 1000°F), a pressure between about 0.1 and about 30 atm, and preferably atmospheric pressure, and a weight hourly space velocity between about 0.1 and about 30, and preferably between about 1 and about 10. Carrier gases or diluents may be introduced into the reaction zone, such as hydrogen, carbon monoxide, carbon dioxide, or nitrogen.

The methyl alcohol and/or dimethyl ether conversion process described herein can be carried out as a batch process, semi-continuously or continuously using a fixed bed, fluidized bed or moving bed catalyst system. A preferred embodiment employs a catalyst zone in which the alcohol or ether feedstock is passed cocurrently or countercurrently through a moving or fluidized bed or particulate catalyst. This is passed after use to a regeneration zone wherein the coke is burned off in an oxygen-containing atmosphere, e.g. air, at elevated temperature, whereupon the regenerated catalyst is returned to the conversion zone for further contact with the alcohol and/or ether feedstock.

The product stream contains steam and a hydrocarbon mixture of paraffins and olefins which is essentially free of aromatics. This mixture is particularly rich in light olefins, i.e. ethylene and propylene. Generally, a major portion of the total olefins is ethylene + propylene, with the ethylene content of the product exceeding the propylene content. Thus, the major hydrocarbon product represents valuable petrochemicals. The steam and the hydrocarbon products can be separated by methods well known in the art.

The following examples serve to illustrate the synthesis and use of the new crystalline aluminosilicates described above.

example 1

4.43 g KOH (86.4%), 13 g NaOH (96%) and 5.74 g sodium aluminate (43.1% Al[deep]2O[deep]3, 33.1% Na[deep]2O, 24% H[deep]2O) were dissolved in 90 g water. Choline chloride (38 g) was added to the resulting solution, followed by 130 g colloidal silica (30 wt% SiO[deep]2 and 70 wt% H[deep]2O). A gel of the following molar composition was formed:

SiO[deep]2/Al[deep]2O[deep]3 = 26.6

R[high]+/R[high]+ + M[high]+ = 0.38

OH[high]-/SiO[low]2 = 0.68

H[low]2O/OH[high]- = 22.9

K[deep]2O/M[deep]2O = 0.15

where R is choline [(CH[deep]3)[deep]3NCH[deep]2CH[deep]2OH] and M is Na + K:

The resulting gel was mixed for 15 minutes and allowed to crystallize in a propylene container at 99°C (210°F) for 25 days. The resulting crystalline product was filtered from the mother liquor, washed with water and dried at 110°C (230°F). This product showed by analysis the following composition in molar ratios:

0.64 R[deep]2O: 0.47 K[deep]2O: 0.13 Na[deep]2O: Al[deep]2O[deep]3: 10.8 SiO[deep]2

and had the following X-ray diffraction pattern:

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°2 large theta D (Angstrom) intensity

_____________________________________________________________________________________

7.65 11.56 100

9.60 9.21 3

11.65 7.60 25

13.37 6.62 52

14.01 6.32 10

15.45 5.74 31

16.62 5.33 4

17.82 4.98 10

19.40 4.58 64

20.50 4.33 61

21.35 4.16 7

23.31 3.82 55

23.67 3.76 86

24.77 3.59 86

27.03 3.30 34

28.25 3.16 40

30.55 2.926 9

31.35 2.853 84

31.92 2.804 11

33.45 2.679 16

35.70 2.515 4

36.10 2.488 21

39.41 2.286 4

41.02 2.200 7

42.90 2.108 6

43.50 2.080 4

45.75 1.983 4

46.42 1.956 3

48.15 1.890 19

48.83 1.865 5

49.84 1.830 6

A portion of the product of Example 1, fired at 538°C (1000°F) for 16 hours, had the following sorption and surface properties:

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Sorption wt%

____________________________________________________

Cyclohexane = 4.4

n-Hexane = 11.5

Water = 22.2

Surface area, m[high]2/g = 523

Examples 2-7

These examples were performed similarly to Example 1 and resulted in essentially the same X-ray diffraction pattern. The composition of the resulting gel and the product composition together with the adsorption properties and surface area are shown in Table IV below.

Example 8

ZSM-34 can also be synthesized from mixtures containing aluminum sulfate and sodium silicate. Using these reactants, a solution containing 15.98 g of Al[deep]2(SO[deep]4)[deep]3 x 18 H[deep]2O in 100 g of water was added to a solution of 135.4 g of Q-Brand sodium silicate (22.8% SiO[deep]2, 8.9% Na[deep]2O, and 62% H[deep]2O) and 40 g of water to which 4.4 g of KOH (86.4%) and 38 g of choline chloride had been added. A gel of the following molar composition was formed:

SiO[deep]2/Al[deep]2O[deep]3 = 27.2

R[high]+/R[high]+ + M[high]+ = 0.46

OH[high]-/SiO[low]2 = 0.48

H[low]2O/OH[high]- = 39.6

K[deep]2O/M[deep]2O = 0.22

This material was allowed to crystallize in a propylene container at a temperature of 99°C (210°F) for 98 days. The resulting crystalline product was filtered, washed with water and dried at 110°C (230°F) and was found by analysis to be ZSM-34 of the following molar composition:

0.93 R[deep]2O: 0.22 K[deep]2O: 0.08 Na[deep]2O: Al[deep]2O[deep]3: 13.7 SiO[deep]2

The resulting product had the following sorption and surface properties after firing at 538°C (1000°F) for 16 hours:

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Sorption wt%

____________________________________________________

Cyclohexane = 3.1

n-Hexane = 10.5

Water = 19.0

Surface area, m[high]2/g = 528

Example 9

ZSM-34 can also be used to prepare potassium silicate. Using this reactant, a solution of aluminum sulfate containing 15.98 g Al[deep]2(SO[deep]4)[deep]3 x 18 H[deep]2O and 4.4 g H[deep]2SO[deep]4 in 100 g water was added to a solution of 187.5 g potassium silicate (20.8% SiO[deep]2, 8.3% K[deep]2O and 72.9% H[deep]2O), 0.2 g quercetin and 20 g water. Then 9.6 g NaOH and 38 g choline chloride were added.

A gel with the following composition was formed:

SiO[deep]2/Al[deep]2O[deep]3 = 27.2

R[high]+/R[high]+ + M[high]+ = 0.44

OH[high]-/SiO[low]2 = 0.52

H[low]2O/OH[high]- = 40.4

K[deep]2O/M[deep]2O = 0.97

This gel was heated to 99°C (210°F) for 73 days after mixing for 15 minutes. After filtration, the product was washed with water and dried at 110°C (230°F). Upon analysis, the product was found to be ZSM-34 with the following molar composition:

0.94 R[deep]2O: 0.4 K[deep]2O: 0.02 Na[deep]2O: Al[deep]2O[deep]3: 14.5 SiO[deep]2

After firing, this product had the following sorption and surface properties:

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Sorption wt%

____________________________________________________

Cyclohexane = 5.3

n-Hexane = 10.7

Water = 17.8

Surface area, m[high]2/g = 499

Table IV

Example 10

ZSM-34 was prepared by mixing the following solutions:

A. Alkali aluminate

69.89 g sodium aluminate (20% Na,

43.1% Al[deep]2O[deep]3, remainder H[deep]2O)

29.28 g NaOH (77.5% by weight Na[deep]2O)

26.4 g KOH (86.4% KOH)

540 g H[deep]2O

B. Silicon dioxide "solution"

780 g colloidal silicon dioxide sol (30% SiO[deep]2)

C. Choline chloride

228g

Solution C was added to Solution A in a 2-liter autoclave with mixing, then Solution B was added and mixed continuously for 15 minutes. The autoclave was then sealed and heated to 149°C (300°F) and held at that temperature for 8 days. The contents were constantly stirred during this 8-day crystallization period.

The autoclave and its contents were then cooled to room temperature, filtered and washed to separate the crystalline product from the reaction mixture. By X-ray diffraction analysis, the resulting product was found to be ZSM-34 with the following contents:

% by weight

0.68

K3.59

Al[deep]2O[deep]3 13.5

SiO[deep]2 78.5

N2.0

This product had the following molar composition:

0.54 R[deep]2O: 0.11 Na[deep]2O: 0.35 K[deep]2O: Al[deep]2O[deep]3: 9.87 SiO[deep]2

The adsorption and surface properties were as follows:

____________________________________________________

Sorption wt%

____________________________________________________

Cyclohexane = 3.5

n-Hexane = 9.6

Water = 19.7

Surface area, m[high]2/g = 448

Example 11

This example was carried out as in Example 10 except that the reaction temperature was lowered to 121°C (250°F) and the reaction time was extended to 11 days.

The product obtained had the following molar composition:

0.52 R[deep]2O: 0.159 Na[deep]2O: 0.34 K[deep]2O: Al[deep]2O[deep]3: 9.65 SiO[deep]2

and a surface area of 512 m[high]2/g.

Example 12

A ZSM-34 sample prepared as in Example 7 was ion exchanged to yield the hydrogen form of the zeolite by treating it with a 10 weight percent aqueous solution of ammonium chloride for five cycles of one hour at 85°C (185°F) followed by firing in air at 538°C (1000°F) for 10 hours.

Catalytic cracking of n-hexane was carried out using the obtained exchanged ZSM-34 as catalyst by means of a small alpha assay described in the Journal of Catalysis, Volume IV, No. 4, August 1965, pages 527-529.

In this test, 0.5 cm3 of catalyst, sized to 1.4 to 0.7 mm (14 to 25 mesh), was contacted with n-hexane at a vapor pressure of 110 mm. This test was run at 371°C (700°F) with the products analyzed after 5 minutes showing 21.3 weight percent conversion. The calculated small alpha value, or relative activity in cracking n-hexane compared to standard silica/alumina, was 877.

Example 13

Cracking with NH[low]4[high]+-exchanged ZSM-34, prepared as in Example 6, was evaluated as described in Example 12, but at 427°C (800°F), conversion 22.1 wt% after 5 min, calculating a small alpha value of 163.

Example 14

Propylene polymerization with the hydrogen form of ZSM-34 prepared as in Example 6 was carried out as described below.

Propylene was passed over a fired sample of 2.6 cm3 (1.0348 g) of ZSM-34 catalyst contained in a tubular glass reactor equipped with an axial heat source at atmospheric pressure. The catalyst was preheated in air flowing at 10 cm/min at 538°C (100°F) for 1.25 h and then purged with helium while the reactor temperature was adjusted to 316°C (600°F).

The reactor effluent was collected and analyzed between 1 and 2 hours of operation. Under these conditions, weight hourly space velocity of 1.3, 316°C (600°F), 81.7 weight percent of the propylene was converted based on recovered products. On a converted products basis, the yield was 96.6 weight percent C[low]4[high]+ and 83.7 weight percent C[low]5[high]+.

Testing of the same catalyst at a weight hourly space velocity of 7.9 and 316°C (600°F) resulted in 34.2 weight percent conversion of the propylene with a yield of 97.5 weight percent C[low]4[high]+ and 90.6 weight percent C[low]5[high]+ based on converted products. At a weight hourly space velocity of 8.4 and 371°C (700°F) the conversion was 52 weight percent with a yield of 82.5 weight percent C[low]5[high]+ based on converted products.

Example 15

Cracking with a fired NH[low]4[high]+-exchanged ZSM-34 prepared as in Example 5 was evaluated as described in Example 12, but at 427°C (800°F), resulting in 27 weight percent conversion to

5 min with a calculated small alpha value of 205.

Example 16

Propylene polymerization with the hydrogen form of ZSM-34 prepared as in Example 15 was evaluated as described in Example 14. Here, 0.67 cm[high]3 (0.25 g) of catalyst was contacted with the propylene at 316°C (600°F). Under these conditions, with a weight hourly space velocity of 7.9, 316°C (600°F), 31.6 weight percent was converted and, based on the products converted, the yield was 96.8 weight percent C[low]4[high]+ and 88.1 weight percent C[low]5[high]+. Another approach using 2.5 cm[high]3 (1.0249 g) of catalyst at 316°C and a weight hourly space velocity of 1.3 resulted in 76.1 weight percent conversion of the propylene feed and a yield of 96 weight percent C[low]4[high]+ and 83 weight percent C[low]5[high]+ based on converted products.

Example 17

Cracking of NH[low]4[high]+-exchanged ZSM-34, prepared as in Example 3, was evaluated at 427°C (800°F) as described in Example 12. Conversion after 5 min was 38.9%, which calculates a small alpha value of 322.

Example 8

Propylene polymerization with the hydrogen form of ZSM-34 prepared as in Example 17 was evaluated as in Example 14.

Using 0.6 cm3 (0.2535 g) and running at 316°C (600°F) and a weight hourly space velocity of 7.7, 40.1 weight percent of the propylene, based on recovered material, was converted, yielding 97.1 weight percent C4+ and 86.8 weight percent C5+, based on converted products.

Example 19

A sample of the product of Example 3 was processed by firing at 538°C (1000°F) for 10 hours and exchanging with a 10 weight percent NH4Cl solution at 85°C (185°F) and 5 one-hour contacts. After the last contact, the exchanged product was filtered, washed with water, dried at 110°C (230°F), pelletized, sized to a size corresponding to a 1.4 to 0.7 mm (14-25 mesh) clear mesh, and fired in air at 538°C (1000°F) for 10 hours.

Example 20

Methanol was passed over 1.0 g of the ion-exchanged catalyst of Example 19 at a flow rate of 3.85 mL/h at atmospheric pressure and a nominal temperature of 371°C (700°F). The catalyst bed had an axial bed length of 60.3 mm (2 3/8"). The catalyst was pretreated in situ with an air flow of 10 cm[high]3/min at 538°C for 1 hour, followed by a nitrogen purge of 10 cm[high]3/min for 10 minutes, during which the reactor temperature dropped to 371°C (700°F). When methanol was passed over the bed, its temperature profile changed as shown in Table II after 2 hours of operation. The reactor effluent was collected between 1 and 2 hours of operation. Operating conditions and product analysis are given in Table III. In this example, 87.9% of the methanol was converted, of which 21% was converted to an oxygen-free hydrocarbon product. This product consisted of 50.9% ethylene and 27.3% propylene.

Example 21

Dimethyl ether (DME) was passed over 1.0 g of the ion-exchanged catalyst product of Example 19 at a rate of 2.0 L/h and a nominal temperature of 371°C (700°F). The catalyst bed had an axial bed length of 61.9 mm (2 7/16"). The catalyst was pretreated in place with an air flow of 10 cm[high]3/min at 538°C for 1 hour, followed by a nitrogen purge for 10 minutes, during which the temperature dropped to 371°C (700°F). DME was then passed over the bed. The temperature profiles of the catalyst bed after 2 and 6 hours of operation were as shown in Table V. The reactor effluent was collected between 1 and 2 hours and between 5 and 6 hours of operation. The operating conditions and product analyses are shown in Table VI. Between 1 and 2 hours of operation, 39.5% of the DME feed was converted, of which 54.2% was hydrocarbon (oxygen-free). 22.0% of the hydrocarbon phase was ethylene and 15.3% propylene.

Example 22

The catalyst used in Example 21 was fired in situ for 16 hours to burn off residual carbon at 538°C (1000°F) in an air flow of 10 cm[high]3/min. The bed was purged with nitrogen at a flow of 10 cm[high]3/min for 10 minutes during which the temperature dropped to 371°C (700°F). Methanol was passed over the bed at a rate of 4.0 ml/hr at a nominal temperature of 371°C (700°F). The temperature profiles (Table V) of the bed were determined after 2 and 5.5 hours of operation. The reactor effluent was collected between 1 and 2 hours and 4.5 and 5.5 hours of operation. The operating conditions and product analyses are shown in Table VI.

Example 23

Methanol was passed at a flow rate of 3.75 mL/h over 1.0 g of the ion-exchanged catalyst product of Example 19 which had been steamed at 482°C (900°F) for 20 h. The catalyst was nominally 371°C (700°F) and the reactor was at atmospheric pressure with an axial bed length of 57.15 mm (2 1/4"). The catalyst was pretreated in situ with an air flow of 10 cm[high]3/min at 538°C (1000°F) for one hour, then purged with nitrogen at 10 cm[high]3/min for 10 minutes, during which the reactor temperature dropped to 371°C (700°F). When methanol was passed over the bed, its temperature profile changed as shown in Table V after 2 hours of operation. The reactor effluent was collected between 1 and 2 hours of operation.

The operating conditions and product analyses are shown in Table VI. 87.2% of the methanol was converted, of which 17.8% was an oxygen-free hydrocarbon product. This product was 54.6% ethylene and 29.4% propylene.

Example 24

Addition of steam as a diluent improved the selectivity to ethylene. A feed solution of 30 wt. % methyl alcohol and 70 wt. % water was passed over 1.0 g of the catalyst of Example 22 at 3.6 g/h. The reaction was carried out at a nominal temperature of 371°C (700°F) and atmospheric pressure. The catalyst bed had an axial bed length of 63.5 mm (2 1/2"). The catalyst of Example 22 was fired in situ with an air flow of 10 cm[high]3/min at 538°C (1000°F) for 5 hours, then purged with nitrogen at 10 cm[high]3/min for 10 minutes while the reaction temperature dropped to 371°C (700°F). The temperature distribution of the bed after 2 hours of feed overrun is shown in Table V. The effluent from the reactor was collected between 1 and 2 hours of operation. Batch conditions and product analysis are shown in Table VII. The batch converted 72.2% of the methyl alcohol, of which 41.4% was oxygen-free hydrocarbon product. The selectivity to ethylene was 59.7%.

Table V

Table VI

Table VII

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Example 24

Feed material

MeOH/H[low]2O

________________________________________________________________________________

Operating hours 2

Temp.-°C (°F) (nominal) 371 (700)

hourly room flow rate (total) 3.6

MeOH 1.2

Water 2.4

Molar ratio (H[low]2O/MeOH) 3.4/1

Conversion of MeOH, wt% 72.2

Product (wt.%)

DMÄ 3.9

Water (excluding water in feed material) 54.7

Hydrocarbon phase 41.4

Hydrocarbon phase (wt.%)

C[low]1 1.6

C[deep]2= 59.7

C[low]2 1.1

C[deep]3= 23.6

C[low]3 5.2

C[low]4= 5.8

C[low]4 1.3

C[low]5= 1.4

C[low]5 0.3

Example 25

A 603 g sample of 1.4 x 0.7 mm (14 x 25 mesh) ion exchanged ZSM-34 prepared as in Example 19 was fired at 538°C (1000°F) for 10 hours and then placed under vacuum for half an hour. Then the sample was contacted by shaking with 6.3 ml of Zn(NO[deep]3)[deep]2 solution containing 0.291 g Zn(NO[deep]3)[deep]2 (0.0636 g Zn) to introduce about 1 weight percent zinc. The resulting material was then dried at 110°C (230°F) and fired at 538°C for 10 hours. When analyzed, the catalyst contained 0.96 weight percent zinc.

Methanol was passed over 1 g of the above catalyst at a rate of 3.8 ml/hr. The catalyst was air burned in place at 538°C for 1 h with an air flow of 10 cm[high]3/min. Nitrogen was passed over the bed at 10 cm[high]3/min for 10 min, during which the temperature dropped to 371°C (700°F). The operating conditions, temperature profile of the bed and product analysis of the product stream leaving the reactor collected between 1 and 2 h of operation are shown in Table VIII below:

Table VIII

_______________________________________________________________________________

Example

25

_______________________________________________________________________________

Feed material MeOH, wt% 100

axial bed length in mm (inches) 57.15 (2 1/4)

Reactor diameter (mm OD) 8

Temperature profile mm (inches) from top

0 359.4 (679)

12.7 (1/2) 373.9 (705)

25.4 (1) 373.9 (705)

38.1 (1 1/2) 369.3 (697)

50.8 (2) 376.7 (710)

Operating hours of temperature profile 2

Weight-based hourly space velocity 3.0

converted MeOH (wt%) 88.7

Products (excluding feedstock), wt.%

Water 38.3

DMÄ 42.0

Hydrocarbon phase 19.5

Hydrocarbon phase composition (wt.%)

C[low]1 2.6

C[deep]2= 45.2

C[low]2 0.4

C[deep]3= 26.8

C[deep]3 0

C[deep]4= 6.5

C[low]4 2.9

C[low]5[high]+ 15.5

It is shown that of the 88.7% of methanol converted, 19.5% was oxygen-free hydrocarbon product with an ethylene content of 45.2 wt.%.

Example 26

A sample of the calcined alkali ZSM-34 of Example 10 was further processed by contacting it with a 10 weight percent NH[low]4Cl solution for 1 hour at about 85°C (185°F) using 10 ml of solution per gram of ZSM-34. A total of four contactings were made under these conditions, followed by filtration and washing with water until substantially free of chloride.

The product was dried at 110°C (230°F) and fired at 538°C (1000°F) for 10 hours. The residual alkali content, expressed as Na, was 0.035 wt.%, while the residual potassium content was 1.47 wt.%. The product had a surface area of 517 m[high]2/g and the following sorption capacity:

Cyclohexane 2.6 wt.%

n-Hexane 10.0 wt.%

H[deep]2O 18.7 wt.%

Example 27

A feed of 30 weight percent methanol and 70% water was passed over 2.0 g of the catalyst of Example 26 at 7.7 ml/hr. The catalyst, in a 15 ml OD tubular glass reactor, had an axial bed length of 47.6 mm (1 7/8"). The catalyst was air-fired in place at 538°C (1000°F) with an air flow of 10 cm[high]/min for 1 hour. Nitrogen was passed over the bed at a rate of 10 cm[high]/min for 10 minutes during which the temperature dropped to 371°C (700°F). The operating conditions, bed temperature profile, and product analysis of samples of the stream leaving the reactor taken at four different time intervals during operation are shown in Table IX below.

Table IX

From these data it can be seen that the use of ZSM-34 in the conversion of methanol resulted in exceptionally high selectivity for ethylene and propylene. Dimethyl ether converted in the presence of this catalyst also gave good yields of ethylene, although somewhat lower than for methanol. The introduction of steam into the methanol feed served to improve the overall selectivity for ethylene.

Claims (3)

1. Crystalline aluminosilicate zeolite with the composition expressed in molar ratios of oxides M[deep](2/n)O : Al[deep]2O[deep]3 : (8-50) SiO[deep]2 wherein M is a cation of valence n and represents alkali metal, alkaline earth metal, hydrogen, hydrogen precursors, metals of groups 1B, 2, 3, 7A, 8 or rare earth metals, having a powder X-ray diffraction pattern as given in Table I and a sorption capacity after firing at 538°C for n-hexane at room temperature and an n-hexane pressure of 20 mm of at least 9.5 wt.%. 2. Process for the preparation of the zeolites according to claim 1, characterized in that a mixture containing sodium oxide, potassium oxide, silicon dioxide, aluminum oxide, a choline compound and water is prepared with a composition expressed in molar ratios of the oxides: SiO[deep]2/Al[deep]2O[deep]3 10-70 OH[high]-/SiO[low]2 0.3-1.0 H[low]2O/OH[high]- 20-100 K[deep]2O/M[deep]2O 0.1-1.0 R[high]+/R[high]+ + M[high]+ 0.1-0.8 where R[high]+ choline and M is sodium + potassium, heating the mixture to a temperature between 80 and 175°C for a period of 12 hours to 200 days, filtering off the zeolite crystals formed, washing them with water, drying them and, if necessary, firing them at temperatures of 200 to 750°C and subjecting them to an ion exchange treatment. 3. Use of the zeolites according to claim 1 for the preparation of catalysts for the catalytic conversion of an organic feed material.