JPH06644B2 - Method for producing iron-titanium-metal-containing crystalline silicate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a novel iron-titanium-metal-containing crystalline silicate.

Conventionally, a method for producing a hydrocarbon by reacting carbon monoxide and hydrogen in the presence of a catalyst is a Fischer
It is known as Tropsch synthesis and is a catalytic reaction in which a C—C bond is formed from CO and H ₂ as shown in the following formula.

In _{CO + 2H 2 → 1 / nÅCH} 2 Å n + H 2 O The Fischer-Tropsch synthesis, because CO is not go polycondensed while receiving hydrogenation, the catalyst type and reaction conditions of n in the formula The value, that is, the C—C degree of polymerization of the product varies variously, and the types of the product include olefin and paraffin as well as aldehyde and ketone which are incomplete products of hydrogenation and dehydration.

In the Fischer-Tropsch synthesis, an iron-based catalyst is generally adopted, and addition of a trace amount of an alkali metal salt gives a product having a significantly increased C—C polymerization degree,
It has a drawback that the carbon number distribution of the product is extremely difficult to control, and improvement of this drawback is the biggest technical problem in the Fischer-Tropsch synthesis.

On the other hand, among various solid inorganic compounds used for the catalyst, in the porous substance, the area of the inner wall of the pores is several tens to several hundreds times that of the outer surface, so most of the active sites of the catalyst are inside the pores. it is conceivable that. Therefore, if the pore size of the catalyst is appropriate, there are both molecules that are too large to be put in the pores and molecules that are not put in the pores, and molecules that cannot be put in have a very small chance of reacting as compared to molecules that put them. Become. With respect to the product, a molecule having a size larger than the pore is not produced in the narrow pore. Thus, the relationship between the structure of the pores and the shape of the molecule determines the selectivity of the catalyst, and zeolite is one such catalyst. Zeolites are generally crystalline aluminosilicates, which are porous crystals in which (SiO ₂ ) and (AlO ₂ ) ⁻ are three-dimensionally combined, and the entrance of the pores is a crystalline substance. Since they have the same size, they are suitable as a molecular shape selective catalyst.

From such a viewpoint, some combinations of the Fischer-Tropsch synthesis catalyst and zeolite have been made. (PD Caesar, JA Brennan, WE Garwood, J. Cit
io, J.Catal., 56 , 274 (1979); VUSRao, RJGormley, Hyd
rocarbon Proceeding, Nov.139 (1980), EP20140,20141;
However, the conventionally proposed combination of the Fischer-Tropsch synthesis catalyst and the zeolite has been such that the both are simply mixed, or the zeolite is simply impregnated with the Fischer-Tropsch catalytically active component, and the product carbon In terms of number distribution control, it has not yet given satisfactory results.
Recently, crystalline metal silicates such as Fe, Ni, Ti, Ru and Rh have been synthesized and tried to be used as catalysts for Fischer-Tropsch reaction.
(USP3941871; EP0050525 Al; JP-A-56-96720;
JP-A-57-183316; JP-A-57-183317; JP-A-57-1833
20; JP-A-58-74521). In this case, although some improvement was observed in controlling the carbon number distribution of the product, it was not sufficient yet.

In addition, the ratio of olefins in the product is small, which is insufficient as a lower olefin synthesis catalyst.

The present inventors have solved the above problems found in the prior art,
As a result of intensive research to develop a catalyst having high activity and a high proportion of olefins in the product as well as controlling the carbon number distribution of the product, iron sources, titanium sources and various metal sources have been developed. Hydrothermally synthesized iron using the mixture-
The inventors have found that titanium-various metal-containing crystalline silicates meet the purpose, and have completed the present invention.

The iron-titanium-various metal-containing crystalline silicate of the present invention is formed by using a mixture of an iron source, a titanium source and various metal sources in synthesizing the crystalline silicate according to a conventionally known hydrothermal synthesis method. is there.

As mentioned above, the crystalline metal silicate itself is known, but in addition to iron-titanium, V, Mn,
An iron-titanium-metal-containing crystalline silicate formed by using a mixture containing a metal compound such as Sr is not known, and it was used as a catalyst for hydrocarbon synthesis from a mixed gas of carbon monoxide and hydrogen. There is no example.

The iron-titanium-various metal-containing crystalline silicate of the present invention is obtained by hydrothermally synthesizing an aqueous mixture of a silica source, an iron source, a titanium source, various metal sources and an alkali metal ion source according to a conventionally known method. Manufactured. In this case, as the reaction aid, for example, a conventional organic compound such as various tetraalkylammonium compounds can be used. As the silica source, water glass, silica gel, silica sol or silica is used. As the iron source, ferrous sulfate, ferrous chloride, ferric sulfate, ferric chloride
Iron or the like is used. As the titanium source, titanium oxysulfate, titanium sulfate, titanium tetrachloride, etc. are used. As the alkali metal ion source, sodium oxide in water glass, sodium aluminate, sodium hydroxide, potassium hydroxide or the like is used. As the reaction aid, conventionally known various organic compounds, for example, tetraphosphonium compounds, tetraalkyl compounds, ethylenediamine, choline and the like can also be used, but preferably tetraalkylammonium compounds, among which tetraalkylammonium bromide is particularly preferable. preferable.

When the iron-titanium-metal-containing crystalline silicate of the present invention is produced, the raw material reaction mixture generally preferably has the following composition.

Si / Fe (molar ratio): 2 or more Ti / Fe (〃): 0.01 to 3 M / Fe (〃): 0.01 to 3 H ₂ O / SiO ₂ (〃): 30 to 70 R ₄ N ⁺ / SiO ₂ (〃): 0.08 to 0.16 OH ⁻ / SiO ₂ (〃): 0.07 to 0.3 where OH ⁻ represents the amount of hydroxide ion in the mixture, and adjustment of this value can be performed by alkali metal hydroxide, alkali metal oxidation. Use things etc. R ₄ N ⁺ represents the amount of tetraalkylammonium ion. Further, M represents various metals such as V, Mn, Zn, Sr, and Mo.

The aqueous gel mixture having such a component composition is hydrothermally synthesized while being kept under the conditions of usual temperature, pressure and time for producing crystalline silicate. In this case, the reaction temperature is 90-200 ℃,
The temperature is preferably 95 to 170 ° C, and the reaction mixture is subjected to hydrothermal synthesis by heating and stirring for 10 to 200 hours while performing reflux under normal pressure or under self-pressure in a closed container. -Titanium-A variety of metal-containing crystalline silicates can be obtained. The reaction product is processed by filtration or centrifugation to separate the solid matter from the aqueous solution. By subjecting the obtained solid material to a water washing treatment to remove excess ionic substances, and then drying, iron-titanium-various metal-containing crystalline silicates containing an organic compound used as a reaction aid are obtained. Obtainable. This product in air at a temperature of 300-900 ℃, preferably 400-700 ℃ 1-10
By firing for 0 hour, an iron-titanium-various metal-containing crystalline silicate containing no organic compound can be obtained.

The iron-titanium-various metal-containing crystalline silicate of the present invention is usually used as a catalyst in a form in which the organic compound used as the reaction aid is removed. In this case, the iron-titanium-various metal-containing crystalline silicate is used. Can also be used by exchanging an alkali metal ion contained as a cation with another cation. INDUSTRIAL APPLICABILITY The iron-titanium-various metal-containing crystalline silicate of the present invention is used as a catalyst for synthesizing hydrocarbons using a mixed gas of carbon monoxide and hydrogen as a raw material, that is, a Fischer-Tropsch synthesis catalyst. In this case, the Fischer-Tropsch synthesis reaction conditions include:
Conventionally known conditions are adopted, for example, as the reaction temperature
200-500 ° C, preferably 300-450 ° C is adopted, and the reaction pressure is 1-100 atm, preferably 10-50 atm. The H ₂ / CO molar ratio in the raw material mixed gas is 0.2 to
3, preferably 0.5 to 1.

The iron-titanium-various metal-containing crystalline silicate of the present invention is advantageously used as a catalyst for the Fischer-Tropsch synthesis reaction, and other various reactions using zeolite as a catalyst, for example, hydrocarbons from methanol or dimethyl ether. In addition to reactions for synthesis, hydrocarbon decomposition reactions,
It can also be used as a catalyst in an olefin polymerization reaction, an organic compound hydrogenation reaction, an aromatic alkylation reaction, and the like.

Next, the present invention will be described in more detail with reference to examples.

Examples 1 to 6 Colloidal silica (Cataloid SI-3, manufactured by Catalyst Kasei Co., Ltd.)
0), ferrous sulfate heptahydrate, titanium oxysulfate dihydrate, various metal compounds, potassium hydroxide (purity 85%),
Tetra-n-propylammonium bromide and water were added to the first
A uniform aqueous gel-like mixture containing the composition shown in the table,
The mixture was placed in a closed container and heated and stirred at 150 ° C. for 40 hours under self-pressure. The reaction mixture is centrifuged to separate solids, and the solids are washed with water until free of ionic substances,
After drying at 100 ° C., it was baked at 500 ° C. for 15 hours to obtain iron-titanium-various metal-containing crystalline silicate. The X-ray diffraction patterns of these are all ZSM from Mobil.
It was confirmed to be substantially the same as that of -5 zeolite. The BET surface area was about 300 m ² / g.

Examples 8 to 14 The fired bodies of the iron-titanium-various metal-containing crystalline silicates obtained in Examples 1 to 7 were tabletted at a pressure of 400 kg / cm ² .
Then, this was crushed and 20 ml prepared by arranging it to 15 to 30 mesh was filled in a reaction tube having an inner diameter of 20 mm. 100 ml /
Hydrogen treatment is performed for 15 hours at a speed of 400 to 500 ° C for min, and then hydrogen is switched to a mixed gas of carbon monoxide and hydrogen (molar ratio 1: 1) at GHSV = 1000hr ^-1 at 300 ° C to 450 ° C at 25 ° C intervals. The reaction was carried out. The analysis of the product was carried out using a gas chromatograph with argon as an internal standard. Table 2 shows the reaction results. Incidentally, a carbon basis both conversion and selectivity are shown below, were calculated as the selectivity excluding conversion to CO ₂ of the CO conversion rate (CO ₂ yield) as 100.

Comparative Example 1 An iron-containing crystal silicate calcined body was obtained in the same manner as in the example using only the iron source (FeSO ₄ .7H ₂ O). Using this, the reaction was carried out under the same conditions as in the examples. The results are shown below.

As can be seen by comparing this reaction result with that in Table 2 above, it is clear that iron-titanium-various metal-containing crystalline silicates are superior as Fischer-Tropsch synthesis catalysts, especially lower olefin synthesis catalysts. is there.

Front page continued (72) Inventor, Hiroshi Yanagisawa, 1-1, Higashi, Yatabe-cho, Tsukuba-gun, Ibaraki Chemical Research Laboratory (72) Inventor, Haruo Takaya, 1-1, Yatabe-cho, Tsukuba-gun, Ibaraki (56) ) Reference JP-A-53-76199 (JP, A) JP-A-58-74521 (JP, A)

Claims (1)

[Claims] 1. A method for producing an iron-titanium-metal-containing crystalline silicate, which comprises subjecting a mixture containing an iron source, a titanium source, and a metal source of a metal other than iron and titanium to a hydrothermal synthesis reaction.