Copper-silicon catalyst silanized and modified by nitrogen-containing silane coupling agent and preparation method and application thereof

Abstract

The invention discloses a copper-silicon catalyst silanized and modified by a nitrogen-containing silane coupling agent. The copper-silicon catalyst comprises a copper species, silicon dioxide and silicon dioxide silanized and modified by the nitrogen-containing silane coupling agent, wherein the copper species accounts for 10-30wt% of the weight of the copper-silicon catalyst, the silicon dioxideaccounts for 60-85wt% of the weight of the copper-silicon catalyst, and the nitrogen element in the silicon dioxide silanized and modified by the nitrogen-containing silane coupling agent accounts for 0.1-2wt% of the weight of the copper-silicon catalyst. The invention also discloses a preparation method of the catalyst and application of the catalyst in preparation of ethylene glycol through hydrogenation of dimethyl oxalate. After silicon hydroxyl in the copper-silicon catalyst is covered with the nitrogen-containing silane coupling agent, desorption of methyl glycolate is promoted so thatthe stability of the catalyst under severe conditions is improved, and the alkalinity of the catalyst is weakened and generation of by-products is inhibited. The activity of the catalyst is improved by doping the nitrogen element in the catalyst, the electron donating effect of the nitrogen element enables the active copper species to have more excellent hydrogenation activity, and the conversionrate of the catalyst is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of catalysts, and relates to a gas-phase ester hydrogenation catalyst, in particular to a copper-silicon catalyst modified by silanization with a nitrogen-containing silane coupling agent, and a preparation method and application thereof. Background technique [0002] Ethylene Glycol (EG) is an essential chemical product widely used as a solvent, antifreeze, PET raw material, etc. Compared with the petroleum-derived route, the process of producing MEG from coal has become more and more attractive. The process consists of three steps: pressurized gasification of coal to generate syngas, carbon monoxide obtained by catalytic coupling reaction Dimethyl oxalate (DMO), and hydrogenation of dimethyl oxalate to ethylene glycol. Due to the abundance of syngas resources, short process flow and low cost, this process has become one of the main development directions of my country's coal chemical industry. As a key s...

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Problems solved by technology

One is that the silanol on the surface of the copper-silicon catalyst has a certain degree of alkalescence, and the side reaction Guerbet reaction generates alcohols containing three or four carbon atoms as a by-product (hereinafter also used C 3,4 -OH), such as 1,2-butanediol and 1,2-propanediol, the reaction by-products 1,2-butanediol and ethylene glycol have close boiling points, resulting in a significant increase in separation costs and energy consumption; the second is the initial hydrogenation product Methyl glycolate is easy to adsorb and polymerize on the isolated silanol on the surface of the catalyst, resulting in coking and deactivation of the catalyst, and the silanol on the surface of the catalyst may also react with the product methanol to form tetramethoxysilane. Long-term use of the catalyst silica carrier will gradually Corroded, resulting in agglomeration of copper species and catalyst deactivation

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