JPH03123640A - Formation of metallosilicate layer on ceramic foam - Google Patents

Abstract

PURPOSE:To synthetically deposite metallosilicate directly on a porous carrier having a small air permeation resistance by a method wherein a ceramic foam is immersed in a solution of the metallosilicate having a specific chemical composition and crystallized and baked at a specific temp. CONSTITUTION:A ceramic foam is immersed into an aq. solution of sodium hydroxide having a chemical composition 0.30 TPA:0.20Na:1/RMe:1Si:7.5 H2O (wherein R is Si/Me having an atomic ratio of 40-950, TPA represents tetraalkyl ammonium and Me is metal atom), followed by crystallization at a temp. of 100-200 deg.C and then baking in an air stream at a temp. of 500-600 deg.C. After ion- exchange of sodium ions in a metallosilicate layer formed on the ceramic foam with ammonium ions, it is dried and then baked at a temp. of 500-600 deg.C. The passage structure of the ceramic foam is secondarily modified into a porous structure which is effective as a practical catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a metallosilicate layer on a ceramic foam having a channel structure.

Conventionally, metallosilicate catalysts have a high diffusion resistance of reaction components into micropores, so if metallosilicates can be supported by direct synthesis on a porous support with low ventilation resistance, the diffusion resistance can be reduced. Moreover, since the flow path is not linear due to the honeycomb structure, the self-stirring efficiency of the reaction gas is increased, and there are advantages such as good contact between the catalyst and the reaction gas.

The present invention provides metacon IJ'7- to ceramic foam.
The present invention provides a method for forming a metallosilicate layer on a ceramic foam that is effective as a practical catalyst by crystallizing a ceramic foam to create a pore structure that is a secondary modification of the channel structure of the ceramic foam. be.

The present invention has a chemical composition of 0.30 TPA: 0.2 ON.
a: 1/RMe: 1Si: 7.5HzO (in the formula, R: Si/Me atomic ratio 40 to 950, TPA: tetraalkylammonium, Me is a metal atom) in an aqueous solution of sodium hydroxide in an amount corresponding to the composition. Chemical equivalent of TP
AB (tetraalkylammonium bromide) For example, tetrapropylammonium bromide, a water-soluble metal salt, and 5i01 are sequentially dissolved to prepare an aqueous mixture containing no free sodium ions.
or above), and the excess impregnating liquid is centrifuged and then crystallized at a temperature of 100 to 200°C.The obtained ceramic foam is then washed with water and dried. ℃, then the sodium ions in the metallosilicate layer supported on the ceramic foam are ion-exchanged with ammonium ions, washed again with water, dried, and fired at 500 to 600℃. A method of forming a metallosilicate layer is provided.

The reason why the metallosilicate impregnating solution was made to be free of sodium ions is that if sodium ions are present, the surface of the ceramic foam that is the carrier is likely to be melted by the remaining sodium ions in the subsequent firing process, and the foam This is because there is a risk that the flow path structure may be scratched.

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

The type of metal in the metallosilicate 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, or chloride.

For example, when the metallosilicate-supported ceramic foam is a catalyst, in particular a Ga-silicate catalyst for the conversion reaction of methanol to lower olefins, Gat<5ot)s.nHzO is used as the metal salt.

In addition, Co -Mn - is a catalyst for the conversion reaction of synthesis gas.
In the case of a Ru-based catalyst, C0(NO3) is used as a metal salt.
!・68zO, Mn(NOz)z ・6HzO and R
uCl 53H1O is used.

(Example) EXAMPLES The present invention will be explained in further detail by way of Examples below.

5iOz20 gSGas(Soa)s・nHzo
3.43 gs NaOH2, 66g and TPAB
(Tetrapropylammonium bromide) 26.58g
To prepare the impregnating solution from the reagents, first make an aqueous sodium hydroxide solution, and add T P A B -, Gat (S
on) 3HnHzO and Sin are added and dissolved in this order to create an aqueous metallosilicate solution containing no free sodium ions, and 0.97 g of ceramic foam with a diameter of 10 mm and a length of 50 mm is added to this solution. After soaking for a minute, it was centrifuged at 1000 rpm for 30 seconds. The obtained ceramic foam was crystallized at 170° C. for 48 hours. The ceramic foam was then washed with water and dried overnight. Next, after increasing the temperature from room temperature to 540℃ in an air stream for 1 hour, 3.5
Baked for an hour. After calcination, ion exchange was carried out at 80° C. for 1 hour with 1N Nl (, NO3 solution). Next, the product was washed with water for q, and after drying, calcination was performed to obtain a catalyst.

The loading rate of Ga-silicate was 57-t%.

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 X-ray diffraction device, Geigerfl
ex-2013, radiation source Cuk ex, 2θ=5~706
In FIG. 1, C) is a carrier ceramic foam (CF
) pattern, a) is a metallosilicate pattern, b
) is a pattern of ceramic foam with one metallosilicate.

As is clear from the comparison of patterns a) and b), characteristic peaks appear around the 2θ value of 8 to 9″ and around 24°, which means that b) is similar to C). This indicates that it has a pentasil structure.

This confirmed that the metallosilicate was synthesized into a pentasil-type metallosilicate on the solid ceramic foam.

A synthesis reaction of lower olefinic hydrocarbons from methanol was carried out using the Ga-silicate supported ceramic catalyst obtained by the method of I3 twist Example 1.

Reaction: A methanol conversion reaction was carried out using a methanol atmospheric pressure flow reactor. Supported catalyst is directly connected to 61
It was used by filling it into a reaction tube. The unsupported catalyst was used by molding synthetic crystals into tablets and crushing them into 15 to 20 mesh pieces. Add to them a raw material gas of 20% MeOH diluted with N2, based on the total volume of the catalyst including the carrier (7) GH5V 1050
The mixture was circulated for 0 h-' and kept at 300°C for reaction. After 3 hours, the produced acid was analyzed using a gas chromatograph equipped with an inch grater.

The equipment used is Shimadzu GC-8A (MeOHlMeOMe,
Co), Shimadzu GC-12A (gaseous hydrocarbon).

The experimental results are shown in Figure 2.

In FIG. 2, a) shows the case where an H-Ga-silicate supported ceramic foam catalyst is used, and b) shows the case where an H-Ga-silicate catalyst is used. In case a), the conversion rate of methanol was 98.3%, and in case b), the conversion rate of methanol was 100%. The fraction of lower hydrocarbons of 62' and C1° is better in case a) than in case b),
Furthermore, the characteristics of the channel structure carrier were utilized to suppress coke formation during the reaction.

(Effects of the Invention) (1) The supporting ratio of metallosilicate on ceramic foam can be easily adjusted.

(2) A channel structure such as a ceramic foam is made into a pore structure by secondary modification of the structure, making it effective as a practical catalyst.

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

[Brief explanation of drawings]

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

Claims (1)

[Claims] Chemical composition 0.30TPA:0.20Na:1/RMe:
1Si:7.5H_2O (in the formula, R: Si/Me atomic ratio 40 to 950, TPA: tetraalkylammonium,
Chemical equivalents of TPAB (tetraalkylammonium bromide), water-soluble metal salts, and SiO_2 are sequentially dissolved in an aqueous solution of sodium hydroxide in an amount corresponding to the composition of Me (Me is a metal atom) to create an aqueous mixture containing no free sodium ions. and impregnate ceramic foam with this solution,
After separating the excess impregnating liquid, it is crystallized at a temperature of 100-200°C and then calcined at 500-600°C in a stream of air, and then the sodium ions of the metallosilicate layer supported on the ceramic foam are A method for forming a metallosilicate layer on a ceramic foam, the method comprising ion-exchanging with ammonium ions, drying, and firing at 500°C to 600°C.