RU2313487C1 - High-silica zeolite and method of production of such zeolite - Google Patents

Abstract

FIELD: production and use of high-silica alumo-silicate zeolite.

SUBSTANCE: proposed high-silica zeolite is used as absorbents and catalysts. Proposed zeolite is produced by hydro-thermal crystallization of reaction mix at temperature of 150-180°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; it has the following chemical composition at molar ratio: SiO₂/Al₂O₃ = 20-100; Na⁺/SiO₂ = 0.1-1.0; OH^-/SiO₂ = 0.1-1.0; H₂O/SiO₂ = 10-100 and mass ratio R/SiO₂ = 0.03-1.0. Used as organic structure-forming additive (R) is "X-oil" fraction -waste of caprolactam production process. Synthetic alumo-silicate zeolites which have structure of type MF1 zeolites and are prepared according to the proposed method with the use of organic structure-forming additive - "X-oil" fraction may be used for production on their base of highly effective catalysts for various reactions of conversion of hydrocarbons.

EFFECT: enhanced efficiency.

3 cl, 4 tbl, 8 ex

Description

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

There are a large number of different high-silica 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 high-silica aluminosilicate zeolites is carried out from aqueous solutions containing sources of silicon, aluminum, an alkali metal, an organic structure-forming compound and a zeolite as a “seed”.

Known zeolite and a method for producing zeolite (US 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 (US 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 an 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 (US 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 while the source of silicon oxide is used 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 high-silica aluminosilicate zeolite structure of the zeolite MFI.

The technical result is achieved by the fact that high-silica 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, E, Relative intensity, 100 · I / I _o ;% 11.31 94 10.12 60 6.31 9 6.03 12 5.79 9 5.67 9 4.98 5 4,58 5 4.37 eleven 4.23 23 4.07 19 3.85 one hundred 3.70 49 3.65 29th 3.48 eleven 3.36 13 3.04 eleven 2.98 twenty 2.48 9 2.12 13 1.99 fifteen

A method of obtaining a high-silica 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 providing 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,

and the mass ratio of R / SiO ₂ = 0.03-1.0;

where R is an organic structure-forming additive;

as an organic structure-forming additive, the “X-oils” fraction (caprolactam production waste) is used, the reaction mixture is crystallized under hydrothermal conditions at 150-180 ° C for 2-7 days, necessary for the formation of high-silica 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 high silica aluminosilicate zeolite is washed with water, dried and calcined.

The invention is illustrated by the following examples.

Example 1. To 103.0 g of water glass (29% SiO ₂ , 9% Na ₂ O, 62% H ₂ O) with constant stirring, add 12.0 g of the fraction of "X-oil" (R), 12.5 g Al (NO ₃ ) ₃ · 9H ₂ O in 200 g of H ₂ O, 0.5 g of the “seed” of the zeolite and added 0.1 N. HNO ₃ solution.

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 = 20.

The mass ratio of R / SiO ₂ = 0.40.

The resulting mixture was loaded into stainless steel autoclaves, heated to 180 ° C and maintained at this temperature for 6 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 calcined aluminosilicate zeolite is 350 m ² / g.

Example 2. Zeolite is obtained in the same way as in example 1, but instead of 12.0 g of the fraction of "X-oil" and 12.50 g of Al (NO ₃ ) ₃ · 9H ₂ O take 6.0 g of the fraction of "X-oil ", 7.50 g of Al (NO ₃ ) ₃ · 9H ₂ O. 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 = 0.60;

OH ^- / SiO ₂ = 0.60;

H ₂ O / SiO ₂ = 20.

The mass ratio of R / SiO ₂ = 0.20.

Example 3. Zeolite is obtained in the same way as in example 1, but instead of 12.0 g of the X-oil fraction and 12.5 g of Al (NO ₃ ) ₃ · 9H ₂ O, 18.0 g of the X-oil fraction are taken ", 6.25 g of Al (NO ₃ ) ₃ · 9H ₂ O and 6.7 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.

The mass ratio of R / SiO ₂ = 0.60.

Example 4. Zeolite is obtained in the same way as in example 1, but instead of 12.0 g of the X-oil fraction and 12.5 g of Al (NO ₃ ) ₃ · 9H ₂ O, 9.0 g of the X-oil fraction is taken "and 4.17 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.

The mass ratio of R / SiO ₂ = 0.30.

Example 5. Zeolite is obtained in the same way as in example 1, but instead of 103.0 g of water glass, 12.0 g of the X-oil fraction and 12.5 g of Al (NO ₃ ) ₃ · 9H ₂ O are taken 100 g an aqueous solution of silica sol (30 wt.% SiO ₂ ), 4.0 g of the X-oil fraction, 3.0 g of NaOH in 50 g of H ₂ O and 9.4 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 = 40;

Na ⁺ / SiO ₂ = 0.15;

OH ^- / SiO ₂ = 0.15;

H ₂ O / SiO ₂ = 20.

The mass ratio of R / SiO ₂ = 0.13.

Example 6. 10 g of a zeolite with a silicate module SiO ₂ / Al ₂ O ₃ = 50, obtained according to example 2, is mixed with 5.1 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 7. 10 g of a zeolite with a silicate module SiO ₂ / Al ₂ O ₃ = 30, obtained according to example 1, is mixed with 5.1 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 a straight-run gasoline fraction with a boiling range of NK-190 ° C and the catalytic properties of the prepared catalyst are shown in Table 3.

Example 8. 10 g of a zeolite with a silicate module SiO ₂ / Al ₂ O ₃ = 50 are mixed with 0.1 g of LiNO ₃ · 3H ₂ O and 4.8 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 reaction conditions for the conversion of paraffinic saturated hydrocarbons With ₂ -C ₄ and the catalytic properties of the prepared catalyst are given in table.4.

In the IR spectra of the obtained high-silica 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 having a structure of the MFI type.

The results of x-ray analysis (Cu-anode, Ni-filter) of a typical high-silica aluminosilicate zeolite obtained using an "X-oil" fraction (caprolactam production waste) as an organic structure-forming additive are presented in Table 1.

The examples given clarify the invention without limiting it.

The proposed technical solution allows to obtain high-silica 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 high-silica aluminosilicate zeolite having an MFI zeolite structure compared to known methods is that it is possible to obtain high-silica aluminosilicate zeolites with an MFI zeolite structure using a cheap organic structure-forming additive — X-oil fraction (waste caprolactam production). While obtaining these zeolites is carried out in a wide range of chemical composition of the initial reaction mixture and in a wide range of crystallization product.

High-silica aluminosilicate crystalline materials having a MFI type zeolite structure prepared in accordance with the invention can be used to produce highly effective catalysts for various hydrocarbon conversion reactions: cracking, dehydrogenation, isomerization and aromatization of normal hydrocarbons, methanol conversion to hydrocarbons and other .

Table 1
X-ray data of high-silica aluminosilicate zeolite obtained using the fraction "X - oil" 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 7.82
8.75
14.06
14.68
15.30
15.62
17.80
19.36
20.30
21.00
21.87
23.12
24.06
24.37
25.62
26.55
29.36
30.00
36.24
44.68
45.62 11.31
10.12
6.31
6.03
5.79
5.67
4.98
4,58
4.37
4.23
4.07
3.85
3.70
3.65
3.48
3.36
3.04
2.98
2.48
2.12
1.99 94
60
9
12
9
9
5
5
eleven
23
19
one hundred
49
29th
eleven
13
eleven
twenty
9
13
fifteen

table 2
The conversion of methanol on a zeolite-containing catalyst (example 6) 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 33.1 5.3 29.1 31.7 66.9

Table 3
The conversion of straight-run gasoline fraction n. K. - 190 ° C on a zeolite-containing catalyst (example 7) 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₊ 99 45.6 2.7 8.0 41.2 54,4

Table 4
The conversion of paraffinic saturated hydrocarbons C ₂ -C ₄ on a zeolite-containing catalyst (example 8) at 650 ° C and a space velocity of 340 h ^-1 Conversion
propane% The yield of products,% Selectivity,% Alkenes C ₂ -C ₄ Arenas Alkenes C ₂ -C ₄ Arenas 51 40.3 0.1 79.3 0.2

Claims (2)

1. High-silica aluminosilicate zeolite, which is a composition of aluminum and silicon oxides, characterized in that the zeolite has a molar ratio of Al ₂ About ₃ · nSiO ₂ , where n = 20-100, the MFI structure and the following radiographic characteristics: Interplanar distance, d, Å, Relative intensity, 100 · I / I _o ; % 11.31 94 10.12 60 6.31 9 6.03 12 5.79 9 5.67 9 4.98 5 4,58 5 4.37 eleven 4.23 23 4.07 19 3.85 one hundred 3.70 49 3.65 29th 3.48 eleven 3.36 13 3.04 eleven 2.98 twenty 2.48 9 2.12 13 1.99 fifteen 2. A method of producing a high-silica 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 and the mass ratio of R: SiO ₂ = 0.03-1.0; and as an organic structure-forming additive (R), an X-oil fraction is used — a caprolactam production waste, crystallization of the reaction mixture is carried out under hydrothermal conditions necessary for the formation of a zeolite having a molar ratio of SiO ₂ : Al ₂ O ₃ = 20-100; said zeolite belongs to the class of zeolites having an MFI structure and the following radiographic characteristics indicated in paragraph 1.