Method for preparing catalyst for shape-selective disproportionation of methylbenzene

Abstract

The invention relates to a method for preparing a catalyst for shape-selective disproportionation of methylbenzene, and mainly aims to solve the problem that the selectively of the catalyst to dimethylbenzene is low in the prior art. The problem is well solved by adopting the method which comprises the following steps of: (a) fully mixing 20-95% by weight of a ZSM-5 molecular sieve with 5-80% by weight of an adhesive to obtain a catalyst precursor; (b) forming hydrosol by using organic silicon and water, performing soaking modification on the catalyst precursor, heating and dehydrating under a vacuum condition, and roasting after dehydrating; and (c) performing the step (b) for 1 to 6 times on the product after roasting to obtain the catalyst for the shape-selective disproportionation of methylbenzene. The method can be used for industrial production of the catalyst for the shape-selective disproportionation of methylbenzene.

Description

technical field

[0001] The invention relates to a preparation method of a toluene shape-selective disproportionation catalyst. Background technique

[0002] Toluene disproportionation reaction is one of the common reactions in industry. It can convert toluene into benzene and xylene with higher application value. The xylene product is an equilibrium composition mixture of its three isomers. Toluene only accounts for about 24%. Therefore, someone proposed a new process of shape-selective disproportionation, so that the reaction system can selectively generate p-xylene. Conventional toluene disproportionation catalysts use mordenite as the main active component. Due to the large pore diameter of mordenite, the three isomers of p-xylene cannot achieve the shape-selective effect. Since ZSM-5 was synthesized in the early 1970s, it has been widely valued due to its unique catalytic performance for reactions such as alkylation, isomerization, disproportionation, selective crackin...

Examples

Embodiment 1

[0016] 100g of the modified precursor containing ZSM-5 molecular sieve with a silicon-aluminum molecular ratio of 25 and 20% by weight of silicon dioxide is impregnated with 100g of hydrosol containing 30% by weight of 275 silicone oil for 2 hours, and then the excess organic silicon hydrosol is filtered off , dried at a temperature of 50°C and a vacuum of 0.08MPa for 10 hours, and then calcined in air at a constant temperature from room temperature to 600°C for 3 hours, and then repeated the above modification process 5 times to obtain catalyst A.

Embodiment 2

[0018] 100g of the modified precursor containing ZSM-5 molecular sieve with a silicon-aluminum molecular ratio of 12.5 and 5% by weight of silicon dioxide is impregnated with 600g of hydrosol containing 40% by weight of methyl silicone oil for 2 hours, and then the excess organic silicon water is filtered off The sol was dried at a temperature of 100°C and a vacuum of 0.06MPa for 6 hours, and then calcined in the air at a constant temperature from room temperature to 700°C for 1 hour, and the above process was repeated twice to obtain catalyst B.

Embodiment 3

[0020] 10g of the modified precursor containing ZSM-5 molecular sieve with a silicon-aluminum molecular ratio of 100 and 80% by weight of silicon dioxide was impregnated with 6000g of 275 silicone oil and 2% by weight of hydrosol for 2 hours, and then filtered off the excess organosilicon hydrosol. Dry at a temperature of 60°C and a vacuum of 0.0001MPa for 100 hours, and then calcine in nitrogen at a constant temperature from room temperature to 500°C for 0.5 hours to obtain catalyst C.

technical field

[0001] The invention relates to a preparation method of a toluene shape-selective disproportionation catalyst. Background technique

[0002] Toluene disproportionation reaction is one of the common reactions in industry. It can convert toluene into benzene and xylene with higher application value. The xylene product is an equilibrium composition mixture of its three isomers. Toluene only accounts for about 24%. Therefore, someone proposed a new process of shape-selective disproportionation, so that the reaction system can selectively generate p-xylene. Conventional toluene disproportionation catalysts use mordenite as the main active component. Due to the large pore diameter of mordenite, the three isomers of p-xylene cannot achieve the shape-selective effect. Since ZSM-5 was synthesized in the early 1970s, it has been widely valued due to its unique catalytic performance for reactions such as alkylation, isomerization, disproportionation, selective crackin...

Examples

Embodiment 1

[0016] 100g of the modified precursor containing ZSM-5 molecular sieve with a silicon-aluminum molecular ratio of 25 and 20% by weight of silicon dioxide is impregnated with 100g of hydrosol containing 30% by weight of 275 silicone oil for 2 hours, and then the excess organic silicon hydrosol is filtered off , dried at a temperature of 50°C and a vacuum of 0.08MPa for 10 hours, and then calcined in air at a constant temperature from room temperature to 600°C for 3 hours, and then repeated the above modification process 5 times to obtain catalyst A.

Embodiment 2

[0018] 100g of the modified precursor containing ZSM-5 molecular sieve with a silicon-aluminum molecular ratio of 12.5 and 5% by weight of silicon dioxide is impregnated with 600g of hydrosol containing 40% by weight of methyl silicone oil for 2 hours, and then the excess organic silicon water is filtered off The sol was dried at a temperature of 100°C and a vacuum of 0.06MPa for 6 hours, and then calcined in the air at a constant temperature from room temperature to 700°C for 1 hour, and the above process was repeated twice to obtain catalyst B.

Embodiment 3

[0020] 10g of the modified precursor containing ZSM-5 molecular sieve with a silicon-aluminum molecular ratio of 100 and 80% by weight of silicon dioxide was impregnated with 6000g of 275 silicone oil and 2% by weight of hydrosol for 2 hours, and then filtered off the excess organosilicon hydrosol. Dry at a temperature of 60°C and a vacuum of 0.0001MPa for 100 hours, and then calcine in nitrogen at a constant temperature from room temperature to 500°C for 0.5 hours to obtain catalyst C.