Preparation method of core-shell titanium silicalite molecular sieve coated zinc-cadmium alloy particle catalyst and method for preparing N, N-diethylhydroxylamine by using core-shell titanium silicalite molecular sieve coated zinc-cadmium alloy particle catalyst

Abstract

The invention belongs to the technical field of chemical engineering, and particularly relates to a preparation method of a core-shell type titanium silicalite molecular sieve coated zinc-cadmium alloy particle catalyst and a method for preparing N, N-diethylhydroxylamine by using the core-shell type titanium silicalite molecular sieve coated zinc-cadmium alloy particle catalyst. Tetrabutyl titanate is used as a titanium source to assemble a shell, and the core-shell type titanium silicalite molecular sieve coated zinc-cadmium alloy particle catalyst is used for preparing N, N-diethylhydroxylamine through diethylamine green oxidation reaction. The core-shell type titanium silicalite molecular sieve coated zinc-cadmium alloy particle catalyst has both titanium oxygen sites and transition metal particles, is a bifunctional catalyst, has the advantages of large pore diameter, large specific surface area, stable skeleton, high catalytic oxidation activity, high selectivity on N, N-diethylhydroxylamine, easy separation and recovery after reaction, reusability, and wide application prospect. Good application prospects are realized.

Description

Technical field [0001] The present invention belongs to the field of chemical technology, in particular to the preparation of a nuclear shell-type titanium silicon molecular sieve coastal cadmium alloy particle catalyst and a method of preparing N, N-dieethyl hydrochloride. Background technique [0002] N, N-diethylhydroxylamine is an important olefin monomer-acting agent, end-based terminator, antioxidant, and organic synthetic intermediate, with N, N-diethyl hydroxylamine use expansion, my country demand year by year increase. At present, N, N-diethylhydroxylamine industrial production technology mainly use triathylene oxidation method, that is, the oxidation and pyrolysis process of triethylamine is oxidized and pyrolysis process, and the process is cumbersome. The pollution is heavy and the production cycle is long, especially in the reaction, producing flammable and explosive gas ethylene, so that there is a certain safety hazard in the production process. Diethylamine and H...

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Problems solved by technology

[0003] Titanium-silicon molecular sieves with titanyl-oxygen sites are green and environmentally friendly catalysts for the catalytic oxidation of secondary amines, but their poor selectivity to the target product hydroxylamine and the characteristics of promoting the deep oxidation of hydroxylamine to nitrones limit their use in the oxidation of secondary amines. In addition, traditional titanium-silicon molecular sieves have smaller pore size (0.56-0.58nm) and specific surface area (360-420m 2 / g) and steric hindrance, making diffusion a controlling process during the reaction

Compared with the traditional titanium-silicon molecular sieve, the hollow titanium-silicon molecular sieve has high titanium content and large pore volume, but the skeleton collapse caused by the dissolution and shedding of the skeleton in the secondary amine catalytic oxidation system is inevitable.

In the presence of transition metal salts - zinc salts or cadmium salts, with H 2 o 2 Hydroxylamine products can also be obtained by solution oxidation of secondary amines, and the presence of transition metal cations reduces the activation energy of the reaction and makes the reaction easier to occur, but there are problems that the catalyst is difficult to recycle and reuse and the selectivity of hydroxylamine is low

What patent CN111909054A discloses is diethylamine, H 2 o 2 , acetone and other solvents in the mixed contact reaction of titanium silicon oxygen catalyst, the selectivity of N,N-diethylhydroxylamine is low, it is not suitable for the efficient conversion of diethylamine oxidation, and it is difficult to reach the level of industrial application

The core-shell titanium-silicon molecular sieve-coated zinc-cadmium alloy particle catalyst is a dual-functional catalyst with both titanium-oxygen sites and transition metal particles. At present, there is no preparation of core-shell titanium-silicon molecular sieve-coated zinc-cadmium alloy particle catalysts. and its public report on the preparation of N,N-diethylhydroxylamine

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