NL8006977A - METHOD FOR PREPARING CRYSTALLINE ZEOLITES - Google Patents

Description

ÏÏ.O. 29,704

Process for the preparation of crystalline zeolites.

The family of crystalline aluminosilicate zeolites known in the literature as ZSM-5 are recognized as particularly suitable as catalysts in various hydrocarbon conversion and adsorption processes. Due to the extraordinary catalytic properties of the ZSM-5 zeolites, there is ongoing research to determine the catalytic effects of the ZSM-5 zeolites on chemical processes, to determine applications and operating parameters for the use of ZSM-5 zeolites in technical hydrocarbon processing and the zeolites can be used technically.

The literature has taught the preparation of ZSM-5 zeolites by crystallization from a heated aqueous reaction mixture containing both the suitable metal oxides and the sources of tetrapropyl ammonium ions or alkylenediamines with 5 to 7 and more carbon atoms. Unfortunately, the organic compounds, especially tetrapropylammonium hydroxide and tetrapropylammonium halides, are expensive and therefore the cost of the completed ZSM-5 zeolite is high compared to other zeolites used in this field.

Br is a continued study of methods for the preparation of ZSM-5 zeolites using inexpensive materials. The object of the present invention is to teach such a method.

It has been found that ZSM-5 zeolites can be prepared using the common, inexpensive chemical ethylenediamine in place of the more expensive tetrapropylammonium or other nitrogenous organic compounds. It was found that the preparation of ZSM-5 from ethylenediamine is sensitive to the group present in the reaction mixture.

Organic nitrogenous bases have been used in the synthesis of crystalline zeolites. It is believed that these organic bases direct the polymerization of aluminate and silica ions in the formation of the zeolite crystal lattice and may be "molds" for the formation of the cores from which the zeolite crystals grow. This structure directing property, from the outset, determines the size and shape of the zeolite crystal frame and consequently the molecular sieve properties of the crystals. In addition, depending on the reaction conditions and the composition of the reaction mixture, different zeolites can be formed from the same organic molds. For example, zeolites ZK-4 * ZSM-4 »faujasite and PHI are prepared from tetramethylammonium compounds; zeolite ZK-5 and ZSM-10 from N, N'-dimethyltriethylene ammonium compounds »ZSM-23 is prepared, from pyrrolidine; ZSM-21 5 from 2-hydroxymethyltrimethylammonium compounds; ZSM-11 from 2-tetra-2-butylammonium hydroxide compounds and ZSM-18 from 1,3 »4» 6,7 »9-hexahydro-2,2,5i5» 8,8-hexamethyl-2H-benzo [1, 2C; 3 * 4C '; 5 6Cn] tri-pyrolium trihydroxide.

ZSM-5 family crystalline zeolites have until recently been prepared only from tetrapropylammonium ion sources, U.S. Patent 3 * 702 * 886 #

US Patent 4 * 108 * 881 describes the preparation of ZSM-5 * ZSM-35 and ZSM-11 from a series of alkylene diamines. * ZSM-5 is described as being prepared from alkyl 15-diamines with 5 * 8 »7 and 12 carbon atoms #

U.S. Pat. No. 4,046,856 discloses the preparation of ferririte-type synthetic aluminosilicates of the ZSM-21 family using organic nitrogen-containing cations derived from ethylenediamine, pyrrolidine, and 2- (hydroxyalkyl) trialkylammonium compounds.

Ethylenediamine has been used to prepare ZSM-35 zeolites »US Patent 4 * 016,245 and ZSM-21 zeolites, US Patent 4 * 046,859 *

The X-ray diffraction patterns of ZSM-35 and ZSM-21 and the chemical and catalytic properties of ZSM-35 and ZSM-21 are not those of ZSM-5 »the zeolites have different crystal structures and different catalytic properties * according to literature *

The finding that ZSM-5 zeolites can be prepared from ethylene-diamine has been embodied in a process for preparing a crystalline aluminosilicate zeolite of the ZSM-5 structure, which (a) comprises the preparation of a mixture of water, a source of ethylenediamine and sources of alkali metal oxide, aluminum or gallium oxide and silicon or germanium oxide (b) allows the formation in this mixture of crystals of the zeolite and (c) includes the recovery of the zeolite.

The finding that the preparation of ZSM-5 from ethylenediamine is sensitive to the composition of the reaction mixture is embodied in a process for the preparation of a crystalline 40 aluminosilicate zeolite of the ZSM-5 structure, which (a) produces 8006977 3 * comprises a mixture of what is, a source of ethylene amine and sources of alkali metal oxides, alumina and silica, which mixture has a composition expressed in the molar ratios of oxides within the following ranges 50H / SiO of about 0.1 to about 0.5 2 H 2 O / OH ™ from about 75 to about 600

SiQ / Al 2 O, from about 20 to about 240 2 2 5 and having a molding value of about 0.1 to about 1.0, (b) allows the formation of zeolite crystals in the mixture and ( (c) includes extraction of the zeolite.

Using the present invention, crystalline aluminosilicate zeolites of the ZSM-5 structure can be prepared using inexpensive ingredients. ZSM-5 zeolites are described in U.S. Pat. No. 3,702 * 886. They have a composition expressed in molar ratios of oxides of: 0.9 - 0.2 τΡ 1 W2 ° 3 * Sro-fcer ^ 2: 2Ï2020 where M is at least one cation with the valence n, W is selected from the group consisting of from aluminum and gallium, Y is selected from the group consisting of silicon and germanium and z is from 0 to 40. The ZSM-5 20 zeolite is characterized by the X-ray diffraction pattern in Table A.

Table A

Interplanar distance d (D): Helative intensity 11.1 ί 0.2 s.

25 10.0 ί 0.2 s.

7> 4 - <M5 z.

7.1 ί 0.15 z.

6.3 - 0.1 z.

6.04) + 0 _ 5.97) 0.1 30 5.56 - 0.1 z.

5.01 ± 0.1 z.

4.60 i 0.08 z.

4.25 ί 0, 8 z.

3.85 i 0.07 s.

35 3.71 - 0.05 s.

3.04 - 0.03 3.

2.99 - 0.02 z.

2.94 - 0.02 z.

The significant lines of Table A as observed in the X-ray diffraction pattern of zeolite ZSM-5 were determined according to standard techniques. Radiation from the copper K-alpha doublet was the source of X-rays and the diffraction pattern was measured using a scintillation counter. The Sig-5 sew was recorded on a strip card holder. The peak signal intensities (I) were recorded as a function of 2 (theta) twice the diffraction angle according to Bragg. From the location of the peak, the corresponding interplanar distances j d, in angstroms, were calculated. The corresponding peak intensities are given by the symbols z.s = very strong, s = strong, m = medium, z = weak and viz = very weak.

Even though standard zeolite crystallization and synthetic methods are used in the preparation of ZSM-5 zeolites from ethylene diamine »the relative concentrations of the components of the reaction mixture * from which the ZSM-5 zeolite is crystallized should be used» be carefully controlled to minimize the occurrence of other unwanted aluminosilicates and silicates. It is believed that ZSM-5 can be prepared from ethylenediamine, because the physical and chemical properties of ethylenediamine in aqueous solution are such that it functions as a mold why ZSM-5 crystal nuclei will be formed. Other cationic and molecular components of the reaction mixture also have the ability to function as molds for the formation of the crystal lattices of other zeolites and minerals. For example, ethylenediamine has been used for the preparation of ZSM-35 and sodium for the preparation of mordenite and zeolite of X and Y type. Therefore, the relative concentrations of all mold types, the types present for which crystal nuclei can be formed, should be controlled. In addition, the relative concentrations of metal oxide, alkali metal oxide and silica sources should be carefully controlled to minimize the generation of undesirable amounts of alumino-silicates such as ZSM-35> magadiite and mordenite * as well as contaminants such as quartz, cristobalite, tridymite and amorphous materials. to make 35.

A number of parameters are used to determine the composition of the solutions from which ZSM-5 is prepared using ethylenediamine.

By *, malformation value ,, as used herein is meant to be an empirically valued quantity, which is determined in the following 8006977 * 5 manner »

The amount "t" represents the mole fraction of mold species * believed to be present in solution as molecular (nonionic) species * for example ethylenediamine instead of ethylenediammonium cation * compared to all potential mold types in solution, ionic and nonionic »t = T / T + S ++ RQ ++ M ++ B + uTn represents the molar concentration of the added 10 nonionic molecular molding species» "B u is the molar concentration of an alkali metal cation * such as sodium or potassium, which is present in the reaction mixture and which is a source of hydroxide ions, MM "is the molar concentration of cations from other sources of hydroxide, for example a tetraalkylammonium-15 hydroxide," RQ * "is the molar concentration of an organic nitrogen source supplied as a 1: 1 salt, for example a tetraalkylammonium halide and "S" is the molar concentration of cation present of added inorganic salts, for example d sodium chloride · 20 The amount of "s" is the mole fraction of cations present in the reaction mixture from salts added to or formed in the reaction mixture. These salts may have been added to facilitate crystallization of the zeolite and prevent silicon oxide lock-up in the grid, as described in U.S. Pat. No. 3 * 849 * 463, compared to all cations present: S + S ss ..... ..

S + + RQ + + M + + B + where MS +, r is the molar concentration of the cation of the added salt, e.g. sodium from sodium chloride.

The amount of "r" is the mole fraction of an ionic organic nitrogen compound, which provides a molding cation type with respect to other ionic molding species. Ionic organic nitrogen compounds, which provide molding cations, are usually in the form of an organic nitrogen salt. -35 substance base, for example ethylenediamine hydrochloride or tetraethyl-amraonium bromide: r = HQ + / RQ + + M + + B +

The amount of nbH is the mole fraction of cations of hydro-8 0 069 7 7 xyl groups contributing species BOH or B ^ O to the total of the species contributing hydroxyl species as defined above, both inorganic and organic nitrogenous base compounds: b = B + / B + + M + 5 Next, the mole fraction of a particular mold type will be one of the following expressions: γ = t = T / (T + S ++ R ++ M ++ B +) = s (1-t) = S + / ( T + S ++ R ++ M + B +)

Zj = r (1-s) (1-t) = R + / (T + S ++ R ++ M ++ B +) 10 = b (1-r) (1-s) (1-t) = B + / (T + S ++ R ++ M ++ B +) = (1-b) (1-r) (1-s) (1-t) = M + / (T + S ++ R ++ M + + B +) 5 where the sum of ^ * 1.

For the present invention, the mold type will be a reaction mixture, for example, 15 T = ethylenediamine, S + = sodium cations from the addition of a sodium salt, RQ + = ethylenediammonium cations from a salt such as ethylenediammonium hydrochloride, 20 B + = sodium cations from sodium hydroxide or after triumoxide and M + = 0, no second source of hydroxide cation has been added. Then, the critical mold value is the ethylene diamine ratio of when the ethylene diamine is added as such, or when it is added as a salt such as ethylene diamine hydrochloride.

The mold value (also called / 0) can range from about 0.1 to about 1, but most preferably is about 0.55 to about 0.80.

It will be appreciated that the ethylene diamine molding type can be fed to the reaction mixture as a hydroxide ion source, eg ethylene diamine oxide, as ethylene diamine, as an ethylene diamine hydrohalide or as a mixture of these compounds.

Each of the species, the concentrations of which are represented by T, S +, RQ +, M + or B +, have the ability to function as molders to form an aluminosilicate lattice. The mold value gives the relative concentration of the components of the reaction mixture, which allow the formation of a crystal structure 1 * 0 of predominantly ZSM-5 type.

8006977 7

The molar ratio of silica to alumina (SiC 2 / A 2 O 2) in the reaction mixture should be in the range of about 20: 1 to about 240: 1, preferably about 40: 1 to about 160; 1 and most preferably from about 70: 1 to about 160: 1.

The hydroxide ion to silica ratio in the reaction mixture should be from about 0.1: 1 to about 0.8: 1, and preferably from about 0.3: 1 to about 0.45: 1. Even when the molding value is within the appropriate range, undesirable amounts of ZSM-35 can be generated when the hydroxide: silica ratio is high, while undesirable amounts of the mineral magadiite can be generated when the ratio is low.

The water to hydroxide ion molar ratio in the reaction mixture 15 should be in the range from about 75: 1 to about 600: 1, and preferably from about 80: 1 to about 225: 1.

The ZSM-5 zeolite is usually formed from an aqueous reaction mixture or an aqueous mother liquor from sources of ethylenediamine, sodium silicate solution, sodium eliminate, sodium chloride and hydrogen chloride. Other compounds, which provide sodium, aluminum and silicon oxides, can be substituted as equivalents for these specific reagents in the preparation of the reaction mixture. Each of these oxides can also be supplied from one or more initial reagents and can be mixed in any order. The sodium chloride and hydrogen chloride are used to maintain the appropriate pH and ionic strength levels and facilitate crystal growth and purity.

The pH of the aqueous reaction mixture is usually higher than about 8 and usually in the range of from about 10 to about 13 * Within these wide ranges, it is not necessary to record or control the pH during the crystallization.

After the reaction mixture has been prepared, it can be aged.

The optional aging step can be from about 12 55 hours to about 16 days at about 10 ° C to about 35 ° C.

The zeolite crystals are allowed to form in the reaction mixture either immediately after mixing the ingredients or after the aging step. The reaction mixture is usually kept at an elevated temperature under autogenous pressure during crystallization. The elevated temperature at which the reaction mixture is maintained is usually in the range of from about 50 ° C to about 250 ° C, preferably from about 80 ° C to about 200 ° C, and most preferably from about 100 ° C to about 175 ° C * The elevated temperature is maintained until the 5 ZSM-5 crystals are formed »which can last from several hours to several weeks depending on the composition of the reaction mixture» but usually lasts 5 to 15 days. The elevated temperature is usually achieved in an autoclave or a similar reaction vessel in which the mixture is subjected to autogenous pressures created by heating the mixture.

After the zeolite crystals are formed, they are usually recovered from the cooled reaction mixture by mechanical separation, e.g. filtration. After recovery, the crystals are washed with water, dried and calcined. The calcination usually takes place in air at temperatures above 510 ° C. The catalyst may be subject to the usual ion exchange treatments known to replace the original cations with hydrogen, ammonium, aluminum and rare earths and other metal ions. The catalyst can also be formulated with conventional matrix materials such as natural or synthetic zeolites and inorganic oxides such as clays, silica or metal oxides.

Examples I-XII

Crystallizations were carried out at 1 9 ° C for 8 days under autogenous pressure after aging the mother liquor for 2 days at 25 ° C, except in Example VII, which was not aged. Solutions were prepared with the content expressed in number of moles and mole ratios as described in Table B (ED = ethylenediamine). The amounts of reagents were chosen to give the parameters of Table C. * The crystal structures of the products of the examples were identified and the approximate content of ZSM-5 zeolite was determined from random powder x-ray by di-di ffracti patterns · 8006977 9

Jabel B.

Number of moles of reagents per mole of SiO4 calculated as:

Example ED Na20 NaCl Al2 O ^ SiC> 2 × 20 I 1 * 2 0.2 0.2 0 * 025 1 * 0 60 II 1.2 0.2 0.2 0.0125 1 * 0 120 III 1.2 0.2 0.2 0.00625 1 * 0 120 IV 1.2 0.2 0.2 0.00625 1 * 0 90 V 1.2 0.2 0.2 0.0125 1 * 0 90 VI 0, 9 0.15 0.15 0.025 1 * 0 90 VII 1.2 0.2 0.2 0.025 1 * 0 90 VIII 1.5 0.25 0.25 0.025 1.0 90 IX 0.2 0.2 0 0.0125 1 * 0 90 X 0.4 0.2 0 0.0125 1 * 0 90 XI 0.8 0.2 0 0.0125 1 * 0 90 XII 1.2 0.2 0 0.0125 1 * 0 90

Table C

Example Parameters Product analysis

Si02 / Al203 0H "/ Si02 H20 / 0H" p # ZSM-5 others I 40 0.4 300 2/3 91 II 40 0.4 150 2/3 75 III 80 0.4 300 2/3 56 magadiite IV 160 0.4 300 2/3 46 Magadiite, V 160 0.4 225 .2 / 3 32 Quartz: Tridymite VI 160 0.4 150 2/3 74 Quartz: Tridymite VII 80 0.3 225 2/3 103 VIII 40 0 .4 300 2/3 88 IX 40 0.5 225 2/3 96 X 80 0.4 150 1/3 27 XI 80 0.4 225 1/2 54 XII 80 0.4 225 2/3 73

Examples I-XII show that the production of ZSM-5 zeolite crystals is quite sensitive to the relative concentrations of the components of the reaction mixture.

8006977

Examples XIII-XVIII

Crystallizations were performed at 149 ° C under autogenous pressure for 8 days after aging the reaction mixture at 25 ° C for 2 days. The reaction mixture was prepared using amounts producing the parameters of Table D.

The crystal structures were identified and the approximate content of ZSM-5 zeolite was determined from random powder X-ray beam diffraction patterns.

Table D

Example Parameters Product ana- _ __

SiO 2 / Al 2 O 5 0H "/ SiO 2 H 2 O / 0H" {Q # ZSM-5 others XIII 80 0.4 150 2/3 95 magadiite XIV 90 0.4 150 2/3 90 zsm-35; magadiite XV 80 0.4 75 2/3 95 ZSM-35 XVI 80 0.4 225 2/3 100 XVII 100 0.4 150 2/3 90 amorphous XVIII 80 0.3 150 2/3 90 magadiite

As can be seen from Examples I-XVIII, ZSM-5 can be produced with good purity and reproducibility using ethylenediamine, especially when controlling the relative concentrations of the reagents. Examples XIX - XXX

As discussed above, the preparation of ZSM-5 from ethyl-15-diamine is sensitive to the composition and treatment of the reaction mixture. Examples XIX - XXX illustrate this sensitivity. The mother liquor was prepared to give the parameters of Table E. The aging and crystallization steps were performed as in Examples XIII-XVIII.

8006977 11

Table E

Pre-Parameters image Si02 / A12Q3 0H "/ Si02 H20 / 0H" Product analysis XIX 80 0.1 * 100 2/3 5% ZSM-5; 55% magadiite; 1 * 0% asaoT £ XX 8o 0.3 150 1/3 10% ZSM-5; 90% amorphous XXI 1 * 0 0.1 * 150 2/3 25% ZSM-5; 75% ZSM-35 XXII 80 0.6 150 2/3 100 # ZSM-35 XXIII 80 0.6 100 2/3 100% mordenite xxiv 80 0.1 * 150 2/3 5% ZSM-5; 95% amorphous XXV 1 * 0 0.1 * 750 0.21 100% amorphous XXVI 80 0.5 150 2/3 5% ZSM-5; 5% ZSM-35; 90 # amorphous XXVII 80 0.6 300 1/3 1 * 0% mordenite; 50% ZSM-35 XXVIII 80 0.2 750 0.11 * amorphous XXIX 160 0.1 * 25Ο 0.22 31+% ZSM-5? 66% mordenite XXX 80 0.6 200 1/3 80% mordenite; 10% quartz; 10% ZSM-35

Example XXXI

This example illustrates the preparation of ZSM-5 using ethylenediamine * ΧΛ = 0.6667, ï10 / SiO2 = 0.3, H 2 O / 0H "= 300, SiO 2 / Al 2 O = 1 * 0.

5 An aqueous aluminosilicate suspension of nominal (mol) composition.

0.15 Na2Q0.15 NaCl: 0.9 ED; 0.025 Al2 / SiOgj 70 E ^ was prepared as follows:

To a solution of 1.19 g sodium aluminate (38% 10 33% Na 2 O, 19% H 2 O), 12.32 g ethylenediamine and 1.97 g sodium chloride dissolved in 50 g water, a silica sol consisting of 1 * was added. 1.55 g Ludox AS (30.1% SiO2) dissolved in 270 g water and a sodium hydroxide solution consisting of 2.09 g sodium hydroxide (97% NaOI) dissolved in 9.90 g distilled water. The aqueous suspension was homogenized for 15 minutes and stored at room temperature for 1 * 8 hours. The final pH was 13.0.

The Teflon autoclave was closed and the reaction mixture was heated to 153 ° C without stirring under autogenous pressure for 8 days. At the end of the crystallization period, 8006977, the reservoir was cooled and the crystalline product was collected by filtration. The pH of the filtrate was 11 * 7 * After the zeolite was washed with distilled water free from chloride * the crystalline product was dried overnight at 110 ° C under a nitrogen vacuum of 6.6 kPa and then for a total of 10 hours Calcined at 540 ° C to remove organic and other volatile impurities.

X-ray analysis of the product indicated 100% ZSM-5

The silica / alumina molar ratio was 57 ea and the product contained less than 0.05 Na 2 O.

Example XXXII

This example illustrates the preparation of HZ5M-5 catalyst particles from the product of Example XXXI.

11.4 g of the calcined product of Example XXXI were mixed with 0.7 g of "Keltrol" (a guar gum food product) and 10.4 g of water to form an extrudable paste. The plastic mass was extruded through a 1.6 mm nozzle to form a bonded zeolite mass. This was dried in an air drying oven overnight at 66 ° C.

The extruded particles were then exchanged four times at 80 ° C for one hour with amounts of 220 ml of 2 molar NH 2 NO 2 in a solvent of equal parts of isopropanol and water and then washed twice with room temperature of 250 ml of isopropanol at room temperature. The exchanged zeolite was dried in an air drying oven overnight at 66 ° C.

The extruded particles were calcined in air at 540 ° C for 10 hours to remove the Keltrol binder and impurities, as well as to decompose the ammonium zeolite to the hydrogen form.

This product showed essentially no decomposition and contained less than 200 ppm N, less than 150 ppm Cl and less than 50 ppm Na. When this product was evaluated for catalytic activity for o-xylene isomerization, the results indicated that it was comparable to other HZSM-5 products prepared with more expensive reagents. (A mixture of 10 moles # o-xylene in benzene was reacted with the zeolite product at 204 ° C by passing the feed through a catalyst bed at a transfer rate of 10 and h 2 / hc = 10).

40 8006977

Claims (7)

2. Process for preparing a crystalline aluminosilicate zeolite with ZSM-5 structure, characterized in that (a) a mixture is prepared of water, a source of ethylene diamine and sources of alkali metal oxides, aluminum oxide and silicon oxide. , which mixture has a composition expressed in mole ratios of oxides within the following ranges: 0H "/ SiO2 0.1 to 0.5 H 2 O / 0H ~ 75 to 600 SiO 2 / Al 2 O 20 to K0 20 and having a mold value of about 0 , 1 to about 1.0, (b) the crystals of the zeolite in this mixture are formed and (c) the zeolite is recovered. 3. Process according to claim 2, characterized in that a mold-forming value from about 0.55 to about 0.80 is used. J *. Process according to claim 2, characterized in that a SiO 2 / Al 2 O 0 mol ratio is used from about ifO to about 160. 5. Process according to claim 4, characterized in that a SiO- / Al-0 molar ratio of from about 70 to about 10O is used. 6. Process according to claim 2, characterized in that a molar ratio of HgO / OH ** is used from approximately 80: 1 to approximately 225: 1 * 35. Process according to claim 2, characterized in that step b allows the zeolite crystals to form from this mixture while the mixture is kept at an elevated temperature. 8. Process according to claim 7, characterized in that an elevated temperature is used from about 80 069 7 7 50 ° C to about 250 ° C. 9. Process according to claim 2, characterized in that the aging of the mixture of step (a) is used as an additional step. 10. Process according to claim 9, characterized in that the aging is carried out at a temperature from about 10 ° C to about 35 ° C for about 12 hours to about 16 days. 11. Process according to claim 2, characterized in that the additional step (d) is to use the calcination of the zeolite in air. ********* 8 0 069 7 7