RU2313486C1 - Method of production of synthetic zeolite - Google Patents

Abstract

FIELD: production of synthetic zeolite and use of such zeolite as adsorbents and catalysts.

SUBSTANCE: proposed synthetic alumo-silicate zeolite is produced by means of hydro-thermal crystallization of reaction mix at temperature of 150-280°C continued for 2-7 days; reaction mix contains source of silicon oxide, aluminum oxide, alkaline metal cations, zeolite "seed", organic structure-forming additive and water; its chemical composition is expressed in the following molar ratio: SiO₂/Al₂O₃ =20-100; Na⁺/SiO₂ = 0.1-1.0; OH/SiO₂= 0.1-1.0; H₂)/SiO₂ = 10=100; R/SiO₂ = 0.03-1.0, where alcohol fraction of caprolactam production process is used as organic structure-forming additive (R). Zeolites thus produced have structure, type MFI; they may be used for production of highly effective catalysts on their base for various reactions of hydrocarbon conversion.

EFFECT: enhanced efficiency.

3 cl, 4 tbl, 9 ex

Description

The invention relates to synthetic zeolite, to a method for its preparation and use as adsorbents and catalysts.

It is known that crystalline aluminosilicates and various substituted aluminosilicates with a micro-, mesoporous zeolite structure are used as adsorbents and catalysts for the conversion processes of various types of hydrocarbon feedstocks. Currently, there are a large number of different micro-, mesoporous aluminosilicate and isomorphically substituted by various elements aluminosilicate zeolite structures, each of which is characterized by individual physicochemical and adsorption properties and has the structure of MFI, MEL, MFI / MEL and other types of zeolites.

The synthesis of aluminosilicate and various substituted aluminosilicate zeolites is carried out from aqueous solutions containing sources of silicon, aluminum, isomorphically substituting aluminum elements, an alkali metal, an organic structure-forming compound and a zeolite as a “seed”.

A known zeolite and a method for producing zeolite (Pat. RU No. 2056354, C01B 39/00, 1993). The method of producing zeolite includes the preparation of seed, the preparation of pulp, consisting of sources of silicon, aluminum, isomorphically substituting aluminum elements or without them, water, alkali, organic matter in an amount of not more than 10 wt.% Of the mass of the pulp or without it and pre-ground seed crystallization of zeolite and boron and iron are used as isomorphically substituting aluminum elements in an amount of not more than 0.5 wt.% by weight of the pulp and the seed is prepared by grinding at a moisture content of 5-60 wt.%. Butanol is used as an organic structure-forming compound; after crystallization of the reaction mixture, a zeolite of the ZSM-5 type is obtained.

A known zeolite and a method for producing high-silica zeolites of the ZSM-5 type (Pat. RU No. 1527154, C01B 33/28, 1987). High-silica zeolites of the ZSM-5 type with a silicate module SiO ₂ / Al ₂ O ₃ = 30-200 are obtained by hydrothermal crystallization of the reaction mixture at 120-180 ° C for 1-7 days, containing sources of silicon oxide, aluminum oxide, alkali metal oxide, the product of the oxidation of hexamethylenediamine and water.

A known zeolite and a method for producing zeolites having a crystalline structure of MTT using small neutral amines (US Pat. RU No. 2148015, C01B 39/48, 1990).

The preparation of zeolite includes the preparation of an aqueous solution from sources of alkali metal oxide, alkaline earth metal oxide or mixtures thereof, sources of an oxide selected from oxides of aluminum, iron, gallium, indium, titanium or mixtures thereof, sources of oxide selected from silicon oxides, germanium or mixtures thereof and at least one neutral amine having a total of four to eight carbon atoms and capable of forming said zeolite, said amine contains only carbon, nitrogen and hydrogen atoms, one primary, a secondary or tertiary but not quaternary amino group and a tertiary nitrogen atom or at least one tertiary carbon atom or a nitrogen atom attached directly to at least one secondary carbon atom; maintaining an aqueous solution under conditions sufficient to form zeolite crystals. Isobutylamine, diisobutylamine, diisopropylamine and trimethylamine are used as small neutral amines for the synthesis of MTT zeolite and hydrothermal synthesis is carried out at a temperature of from 100 to 250 ° C for 1-7 days.

Known synthetic porous crystalline material and the method of its production, adopted as a prototype (Pat. RU No. 2058815, B01J 37/00, B01J 29/04, 1990). A synthetic porous crystalline material, which is a composition of oxides of trivalent metal and silicon, while the oxide of trivalent metal contains aluminum oxide, or boron, or gallium, in the following molar ratio: X ₂ O ₃ · nSiO _2, where X is trivalent metal, n = 20-40, the specified material is designated MCM-22.

A method for producing a synthetic porous crystalline material based on trivalent metal and silicon oxides, comprising preparing a reaction mixture containing sufficient amounts of alkali metal cations, a silicon oxide source, a trivalent metal oxide source, water and hexamethyleneimine, crystallizing this mixture, separating the precipitate formed, drying and calcining however, as the source of silicon oxide using an oxide-containing silicon compound containing at least 30 wt.% solid silicon dioxide, oxide-containing compounds of aluminum, or boron, or gallium are used as a source of trivalent metal oxide, the preparation of the reaction mixture is carried out under conditions providing the following composition of the mixture in a molar ratio:

SiO ₂ / X ₂ O ₃ = 6.1-30.0;

H ₂ O / SiO ₂ = 18.6-44.9;

OH / SiO ₂ = 0.056-0.18;

M / SiO ₂ = 0.056-0.18;

R / SiO ₂ = 0.30-0.35;

where X is aluminum, or boron, or gallium;

M is an alkali metal;

R is hexamethyleneimine,

and crystallization is carried out under conditions sufficient to form a crystalline material having the following molar ratio X ₂ O ₃ · nSiO _2, where X is a trivalent metal, n = 20-40, the material is designated MCM-22.

The objective of the invention is to obtain a synthetic aluminosilicate zeolite structure of the zeolite MFI.

The technical result is achieved by the fact that the synthetic aluminosilicate zeolite, which is a composition of aluminum and silicon oxides with a molar ratio of Al ₂ O ₃ · nSiO ₂ , where n = 20-100, has a MFI zeolite structure and the following radiographic characteristics:

Interplanar distance, d, Å, Relative intensity, 100 · I / I _about ; % 11.05 one hundred 10.00 58 6.76 5 6.39 10 6.03 fifteen 5.72 9 5.59 13 5.02 9 4.63 8 4.40 13 4.29 twenty 4.07 16 4.02 13 3.87 one hundred 3.83 80 3.73 63 3.66 34 3.45 fifteen 3.32 16 3.06 13 2.99 eighteen 2.49 8 2.02 eleven 2.00 eleven

A method of producing a synthetic aluminosilicate zeolite based on aluminum and silicon oxides involves the preparation of a reaction mixture containing an aluminum source, a silicon source, an alkali metal source, water and an organic structure-forming additive, while the preparation of the reaction mixture is carried out under conditions that provide the following general composition of the mixture in molar ratio :

SiO ₂ / Al ₂ O ₃ = 20-100;

Na ⁺ / SiO ₂ = 0.1-1.0;

OH ^- / SiO ₂ = 0.1-1.0;

H ₂ O / SiO ₂ = 10-100;

R / SiO ₂ = 0.03-1.0;

where R is an organic structure-forming additive;

an alcohol fraction (caprolactam production waste) is used as an organic structure-forming additive, the reaction mixture is crystallized under hydrothermal conditions at 150-180 ° C for 2-7 days, necessary for the formation of an aluminosilicate zeolite having a molar ratio of SiO ₂ / Al ₂ O ₃ = 20-100; the structure of the zeolite MFI and the following radiographic characteristics indicated above.

After crystallization, the synthetic zeolite is washed with water, dried and calcined.

The invention is illustrated by the following examples.

Example 1. To 206.9 g of water glass (29% SiO ₂ , 9% Na ₂ O, 62% H ₂ O), 24.0 g of the alcohol fraction (R), 24.98 g of Al (NO ₃ ) are added with stirring ₃ · 9H ₂ O in 160 g of H ₂ O, 1 g of “seed” of high-silica zeolite and a 0.1 N HNO ₃ solution is added.

The reaction mixture has the following chemical composition, expressed in molar ratios:

SiO ₂ / Al ₂ O ₃ = 30;

Na ⁺ / SiO ₂ = 0.60;

OH ^- / SiO ₂ = 0.60;

H ₂ O / SiO ₂ = 10;

R / SiO ₂ = 0.30.

The resulting mixture was loaded into stainless steel autoclaves, heated to 175 ° C and kept at this temperature for 7 days, then cooled to room temperature. The synthesized product is washed with water, dried at 110 ° C for 7-8 hours and calcined at 550-600 ° C for 12 hours. The calcined product according to the data of IR spectroscopy and X-ray diffraction analysis has a high degree of crystallinity and a set of basic reflexes are given in table. one.

To convert to the H-form, the zeolite is decationized by treatment with a 25 wt.% Aqueous solution of NH ₄ Cl at 90 ° C for 2 hours, then washed with water, dried at 110 ° C for 4-6 hours and calcined at 600 ° C for 8 hours. the surface of the calcined crystalline material is 329 m ² / g.

Example 2. Zeolite receive the same as in example 1, but instead of 24.0 g of the alcohol fraction and 24.98 g of Al (NO ₃ ) ₃ · 9H ₂ O take 8.0 g of the alcohol fraction, 15.00 g of Al ( NO ₃ ) ₃ · 9H ₂ O and 5.38 g of NaOH. The crystallization time of the reaction mixture at 180 ° C for 2 days.

The reaction mixture has the following chemical composition, expressed in molar ratios:

SiO ₂ / Al ₂ O ₃ = 50;

Na ⁺ / SiO ₂ = 0.73;

OH ^- / SiO ₂ = 0.73;

H ₂ O / SiO ₂ = 30;

R / SiO ₂ = 0.10.

Example 3. Zeolite is obtained in the same way as in example 1, but instead of 24.0 g of the alcohol fraction and 24.98 g of Al (NO ₃ ) ₃ · 9 H ₂ O take 40.0 g of the alcohol fraction, 12.5 g of Al (NO ₃ ) ₃ · 9H ₂ O and 13.38 g of NaOH. The crystallization time of the reaction mixture at 180 ° C for 4 days.

The reaction mixture has the following chemical composition, expressed in molar ratios:

SiO ₂ / Al ₂ O ₃ = 60;

Na ⁺ / SiO ₂ = 0.93;

OH ^- / SiO ₂ = 0.93;

H ₂ O / SiO ₂ = 50;

R / SiO ₂ = 0.50.

Example 4. Zeolite is obtained in the same way as in example 1, but instead of 24.0 g of the alcohol fraction and 24.98 g of Al (NO ₃ ) ₃ · 9H ₂ O take 32.0 g of the alcohol fraction and 10.5 g of Al ( NO ₃ ) ₃ · 9H ₂ O. The crystallization time of the reaction mixture at 180 ° C for 4 days.

The reaction mixture has the following chemical composition, expressed in molar ratios:

SiO ₂ / Al ₂ O ₃ = 70;

Na ⁺ / SiO ₂ = 0.60;

OH ^- / SiO ₂ = 0.60;

H ₂ O / SiO ₂ = 50;

R / SiO ₂ = 0.40.

Example 5. Zeolite is obtained in the same way as in example 1, but instead of 24.0 g of the alcohol fraction and 24.98 g of Al (NO ₃ ) ₃ · 9H ₂ O take 12.0 g of the alcohol fraction and 8.33 g of Al ( NO ₃ ) ₃ · 9H ₂ O. The crystallization time of the reaction mixture at 175 ° C for 6 days.

The reaction mixture has the following chemical composition, expressed in molar ratios:

SiO ₂ / Al ₂ O ₃ = 90;

Na ⁺ / SiO ₂ = 0.60;

OH ^- / SiO ₂ = 0.60;

H ₂ O / SiO ₂ = 40;

R / SiO ₂ = 0.15.

Example 6. Zeolite is obtained in the same way as in example 1, but instead of 206.9 g of water glass, 24.0 g of the alcohol fraction and 24.98 g of Al (NO ₃ ) ₃ · 9H ₂ O take 200 g of an aqueous solution of silica sol ( 30 wt.% SiO ₂ , 1 wt.% NaOH), 8.0 g of the alcohol fraction, 6.0 g of NaOH in 50 g of H ₂ O and 18.75 g of Al (NO ₃ ) ₃ · 9H ₂ O. Crystallization time the reaction mixture at 175 ° C for 6 days.

The reaction mixture has the following chemical composition, expressed in molar ratios:

SiO ₂ / Al ₂ O ₃ = 40;

Na ⁺ / SiO ₂ = 0.20;

OH ^- / SiO ₂ = 0.20;

H ₂ O / SiO ₂ = 20;

R / SiO ₂ = 0.10.

Example 7. 7 g of a zeolite with a silicate module SiO ₂ / Al ₂ O ₃ = 50, obtained according to example 2, is mixed with 3.53 g of boehmite AlO (OH). The resulting powder is molded, dried for 4 hours at 20-25 ° C, then at 110 ° C for 8 hours and calcined in air for 8 hours at 550-600 ° C.

The resulting catalyst has a composition, wt.%:

Zeolite (SiO ₂ / Al ₂ O ₃ = 50) 70.0; Al ₂ O ₃ 30.0.

For catalytic tests, a catalyst fraction of 2-3 mm is prepared. The conditions for the methanol conversion reaction and the catalytic properties of the prepared catalyst are given in table 2.

Example 8. 7 g of a zeolite with a silicate module SiO ₂ / Al ₂ O ₃ = 30, obtained according to example 1, is mixed with 3.53 g of boehmite AlO (OH).

The resulting powder is formed, dried for 2 hours at 20-25 ° C, then at 110 ° C for 12 hours and calcined in air for 12 hours at 550-600 ° C.

The resulting catalyst has a composition, wt.%:

Zeolite (SiO ₂ / Al ₂ O ₃ = 30) 70.0; Al ₂ O ₃ 30.0.

For catalytic tests, a catalyst fraction of 2-3 mm is prepared. The reaction conditions for the conversion of straight-run gasoline fraction n. K. -190 ° C and the catalytic properties of the prepared catalyst are given in table.3.

Example 9. 7 g of a zeolite with a silicate module SiO ₂ / Al ₂ O ₃ = 50 are mixed with 0.082 g of LiNO ₃ · 3H ₂ O, 3.34 g of boehmite AlO (OH). The resulting powder is molded, dried for 2 hours at 20-25 ° C, then at 110 ° C for 2-3 hours and calcined in air for 6 hours at 550-600 ° C.

The resulting catalyst has a composition, wt.%:

Zeolite (SiO ₂ / Al ₂ O ₃ = 50) 70.0; Li ₂ O 1.6; Al ₂ O ₃ 28.4.

For catalytic tests, a catalyst fraction of 2-3 mm is prepared. The conditions for the conversion reaction of gaseous saturated hydrocarbons C ₂ -C ₄ and the catalytic properties of the prepared catalyst are given in table 4.

In the IR spectra of the obtained synthetic aluminosilicate zeolites, absorption bands are observed at 445, 550, 810 cm ^-1 and a wide band in the region of 1000-1300 cm ^-1 , characteristic of zeolites with a MFI type structure. The results of x-ray analysis (Cu - anode, Ni-filter) of a typical synthetic aluminosilicate zeolite obtained using an alcohol fraction as the organic structure-forming additive (caprolactam production waste) are presented in Table 1. The examples given clarify the invention without limiting it.

The proposed technical solution allows to obtain a synthetic aluminosilicate zeolite without the use of expensive organic quaternary ammonium salts, while the chemical composition and properties of the final aluminosilicate zeolite having a MFI type zeolite structure can be controlled by the composition of the initial reaction mixture. Thus, the advantage of this method of preparing a synthetic aluminosilicate zeolite having the structure of an MFI zeolite compared to known methods is that it is possible to obtain zeolites with a structure of zeolites of the MFI type using a cheap organic structure-forming additive - an alcohol fraction (a waste product of caprolactam). While obtaining these zeolites is carried out in a wide range of chemical composition of the initial reaction mixture and the conditions for obtaining the crystallization product.

Synthetic zeolites with the structure of MFI zeolites prepared according to the proposed method using an alcohol fraction as an organic structure-forming additive (caprolactam production waste) can be used to obtain highly effective catalysts for various hydrocarbon conversion reactions: cracking, dehydrogenation, isomerization and aromatization of hydrocarbons normal structure, the conversion of methanol to hydrocarbons and others.

Table 1
X-ray data of a synthetic aluminosilicate zeolite obtained using an alcohol fraction No. / No. of peak Degrees 2θ Interplanar distance, d, Å Relative intensity, I / I _o 100 one
2
3
four
5
6
7
8
9
10
eleven
12
13
fourteen
fifteen
16
17
eighteen
19
twenty
21
22
23
24 8.00
8.85
13.09
13.85
14.68
15,51
15.85
17.68
19.17
20.34
20.85
21.85
22.10
23.00
23.17
23.85
24.34
25.85
26.85
29.17
29.85
36.00
44.85
45.40 11.05
10.00
6.76
6.39
6.03
5.72
5.59
5.02
4.63
4.40
4.29
4.07
4.02
3.87
3.83
3.73
3.66
3.45
3.32
3.06
2.99
2.49
2.02
2.00 one hundred
58
5
10
fifteen
9
13
9
8
13
twenty
16
13
one hundred
80
63
34
fifteen
16
13
eighteen
8
eleven
eleven

table 2
The conversion of methanol on a zeolite-containing catalyst (example 7) at 450 ° C and a methanol space velocity of 2 h ^-1 The conversion of methanol,% The yield of products, wt.% Amount C _4- n-alkanes C ₅₊ i-Alkanes C ₅₊ Arenas C ₅₊ Amount C ₅₊ one hundred 30.5 4.3 35.7 28,4 69.5

Table 3
The conversion of straight-run gasoline fraction NK-190 ° C on a zeolite-containing catalyst (example 8) at 425 ° C and a space velocity of 1 h ^-1 Pentane conversion,% The yield of products, wt.% Amount C _4- n-alkanes C ₅₊ i-Alkanes C ₅₊ Arenas C ₅₊ Amount C ₅₊ 97 40.6 4.1 11.5 37.7 59.4

Table 4
The conversion of gaseous saturated hydrocarbons With ₂ -C ₄ on a zeolite-containing catalyst (example 9) at 650 ° C and a space velocity of 340 h ^-1 Propane conversion,% The yield of products,% Selectivity,% Alkenes C ₂ -C ₄ Arenas Alkenes C ₂ -C ₄ Arenas 55 43.5 0.5 81.7 0.9

Claims (2)

1. Synthetic aluminosilicate zeolite, which is a composition of aluminum and silicon oxides, characterized in that the zeolite has a molar ratio of Al ₂ O ₃ · nSiO ₃ , where n = 20-100, the structure of the zeolite type MFI and the following radiographic characteristics: Interplanar distance, d, Å, Relative intensity, 100 · I / I _about ; % 11.05 one hundred 10.00 58 6.76 5 6.39 10 6.03 fifteen 5.72 9 5.59 13 5.02 9 4.63 8 4.40 13 4.29 twenty 4.07 16 4.02 13 3.87 one hundred 3.83 80 3.73 63 3.66 34 3.45 fifteen 3.32 16 3.06 13 2.99 eighteen 2.49 8 2.02 eleven 2.00 eleven 2. A method of producing a synthetic aluminosilicate zeolite based on aluminum and silicon oxides, comprising preparing a reaction mixture containing an aluminum source, a silicon source, an alkali metal source, water and an organic structure-forming additive, crystallization of the reaction mixture, separating the precipitate formed, drying and calcining, characterized in that the preparation of the reaction mixture is carried out under conditions that ensure the overall composition of the mixture in a molar ratio: SiO ₂ : Al ₂ O ₃ = 20-100; Na ⁺ : SiO ₂ = 0.1-1.0; OH ^- : SiO ₂ = 0.1-1.0; H ₂ O: SiO ₂ = 10-100; R: SiO ₂ = 0.03-1.0; as the organic structure-forming additive (R), the alcohol fraction of caprolactam production waste is used, the reaction mixture is crystallized under hydrothermal conditions necessary for the formation of a zeolite having a molar ratio of SiO ₂ : Al ₂ O ₃ = 20-100; the specified zeolite belongs to the class of zeolite having a structure of the MFI type and the following radiographic characteristics specified in paragraph 1.