JPH07121359B2 - Method for forming metallosilicate layer on ceramic foam - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for forming a metallosilicate layer on a ceramic foam having a flow channel structure.

Conventional technology, the problem to be solved by the invention Conventionally, metallosilicate catalysts have a large diffusion resistance of the reaction components to the micropores, so if the metallosilicate can be supported by direct synthesis on a porous carrier having a small air flow resistance, the diffusion resistance will be increased. Since the flow path is not linear due to the honeycomb structure, the self-stirring efficiency of the reaction gas is increased, and the advantage that the catalyst between the catalyst and the reaction gas is good can be obtained.

The present invention forms a metallosilicate layer on a ceramic foam effective as a practical catalyst by crystallizing a metallosilicate on a ceramic foam to form a channel structure such as a ceramic foam into a pore structure obtained by secondarily modifying the constituent. It provides a way to do it.

Means for Solving the Problems The present invention has a chemical composition of 0.30TPA: 0.20Na: 1 / R Me: 1Si: 7.5H ₂ O.
(Wherein R: Si / Me atomic ratio 40 to 950, TPA: tetraalkylammonium, Me is a metal atom), an equivalent amount of TPAB (tetraalkylammonium bromide) is added to an aqueous solution of sodium hydroxide. Tetrapropylammonium bromide, water-soluble metal salt and SiO ₂ are sequentially dissolved to make an aqueous mixed solution containing no free sodium ion,
This solution is impregnated with ceramic foam having a pore size of mesopores or more (20 Å or more), and the excess impregnation solution is, for example, centrifuged and crystallized at a temperature of 100 to 200 ° C, and the resulting ceramic foam is washed with water and dried. 500-600 ℃ in rear air flow
After that, the metal ions of the metallosilicate layer supported on the ceramic foam are exchanged with ammonium ions, washed again with water, and dried at 500 to 600 ° C.
The present invention provides a method for forming a metallosilicate layer on a ceramic foam, which is characterized by firing at.

The reason why the metallosilicate impregnating solution does not contain free sodium ions is that when sodium ions are present, the surface of the ceramic foam, which is a carrier, is easily melted by the sodium ions remaining in the subsequent firing step and the like. This is because the flow channel structure may be damaged.

The amount of metallosilicate supported on the ceramic foam is
It can be easily adjusted by the concentration of the aqueous metallosilicate mixture, the number of centrifugations to remove excess impregnating liquid, the number of times the ceramic foam is impregnated with the impregnating liquid, and the like.

The type of metallosilicate metal supported on the ceramic foam is selected depending on the purpose of use, but is not particularly limited as long as it is a water-soluble metal salt such as nitrate, sulfate and chloride.

For example, when the metallosilicate-supported ceramic foam is a catalyst, particularly a Ga-silicate catalyst which is a catalyst for the conversion reaction of methanol to lower olefins, Ga ₂ (So ₄ ) ₃ · nH ₂ O is used as the metal salt. .

Also the conversion reaction of catalytic syngas Co-Mn-Ru system when a catalyst Co as the metal salt _{(NO 3) 2 · 6H 2} O, Mn (N
O _{3) 2 ·} 6H 2 O and RuCl ₃ 3H ₂ O is used.

(Example) An example is shown below and the present invention is explained still in detail.

Example 1 Ga- silicate / ceramic foam: For _{(R 40) SiO 2 20g,} Ga 2 (So 4) 3 · nH 2 O3.43g, NaOH2.66g and T
When making an impregnating solution from 26.58 g of PAB (tetrapropylammonium bromide), an aqueous solution of sodium hydroxide was first prepared, and TPAB, Ga ₂ (So ₄ ) ₃ , nH ₂ O and Si were added to it.
Added in the order of O ₂ dissolved to make a water-based solution of metallosilicate no free sodium ions, the solution to a diameter 10 mm, 30 seconds at 1000 revolutions was immersed for 1 minute ceramic foam 0.97g length 50mm It was centrifuged. The obtained ceramic foam was crystallized at 170 ° C. for 48 hours. Next, the ceramic foam was washed with water and dried overnight. Next, the temperature was raised from room temperature to 540 ° C. in 1 hour in an air stream, and then firing was performed for 3.5 hours. After firing, ion exchange was performed with a 1N NH ₄ NO ₃ solution at 80 ° C. for 1 hour. Next, it was washed with water, dried and calcined to obtain a catalyst.

The loading of Ga-silicate was 57 wt%.

Measurement of physical properties: The X-ray diffraction pattern of the metallosilicate catalyst supported on the ceramic foam obtained by the method of Example 1 is shown in FIG.

Equipment used: Rigaku Denki X-ray diffractometer, Geigerflex-201
3, radiation source Cuk α, 2θ = 5 to 70 °, in Fig. 1, c) is a carrier ceramic foam (CF)
Pattern, a) is a metallosilicate pattern, b)
Is a pattern of metallosilicate-supported ceramic foam.

As is clear from the comparison between patterns a) and b), characteristic peaks appear at values of 2θ around 8 to 9 ° and around 24 °, which means that b) is similar to c). It shows that it has a pentasil structure.

From this, it was confirmed that the metallosilicate was synthesized as a pentasil-type metallosilicate on the carrier ceramic foam.

Reference Example Using the Ga-silicate supported ceramic catalyst obtained by the method of Example 1, a synthesis reaction of lower olefinic hydrocarbon from methanol was performed.

Reaction: A methanol conversion reaction was carried out using a methanol atmospheric pressure reactor. Directly supported catalyst is 6 mm
The reaction tube of No. 1 was used by filling. The unsupported catalyst was used by crushing synthetic crystals into tablets and crushing into 15 to 20 mesh. A raw material gas of 20% MeOH diluted with N ₂ was passed through them at GHSV 10500h ^{-1 based} on the total volume of the catalyst including the carrier, and the reaction was performed while maintaining the temperature at 300 ° C. After 3 hours, the product was analyzed by a gas chromatograph equipped with an integrator.

Equipment used is Shimadzu GC-8A (MeOH, MeOMe, Co), Shimadzu GC-1.
It was 2 A (gaseous hydrocarbon). The experimental results are shown in FIG.

In FIG. 2, a) is a case where an H-Ga-silicate supported ceramic foam catalyst is used, and b) is a case where an H-Ga-silicate catalyst is used. In the case of a), the conversion of methanol is 9
8.3%, in case of b) the conversion of methanol is 100%
Met. Fraction C ₂ ⁼ and C ₃ ⁼ lower hydrocarbons a)
The case was superior to the case of b), and the characteristics of the flow path structure carrier were utilized, and the effect of suppressing coke formation during the reaction was obtained.

(Effects of the Invention) (1) The loading rate of metallosilicate on a ceramic foam can be easily adjusted.

(2) The flow path structure such as ceramic foam has a pore structure in which the structure is secondarily modified to be effective as a practical catalyst.

(3) The zeolite catalyst could be effectively supported and dispersed.

[Brief description of drawings]

FIG. 1 is an X-ray diffraction diagram of a Ga-silicate supported ceramic catalyst synthesized by the method of the present invention, and FIG. 2 is a distribution of hydrocarbons produced by a methanol conversion reaction by the Ga-silicate supported ceramic catalyst synthesized by the method of the present invention. It is a figure.

Claims (1)

[Claims] 1. Chemical composition 0.30TPA: 0.20Na: 1 / R Me: 1Si: 7.5H
₂ O (wherein R: Si / Me atomic ratio 40 to 950, TPA: tetraalkylammonium, Me is a metal atom) is added to an aqueous solution of sodium hydroxide in a chemical equivalent amount of TPAB (tetraalkylammonium bromide). ), Water-soluble metal salts and SiO ₂
Are sequentially dissolved to form an aqueous mixed solution containing no free sodium ion, this solution is impregnated with ceramic foam, and the excess impregnating solution is separated and then crystallized at a temperature of 100 to 200 ° C. It is characterized in that it is fired at 500 ° C. to 600 ° C., then the sodium ions of the metallosilicate layer supported on the ceramic foam are ion-exchanged with ammonium ions, then dried, and fired at 500 ° C. to 600 ° C. A method of forming a metallosilicate layer on a ceramic foam.