Method of prolonging service life of catalyst in dehydration of glycerol for production of acrolein

Abstract

The invention discloses a method for prolonging the service life of catalyst in dehydration of glycerol for production of acrolein. Reaction conditions in a fixed-bed reactor are changed for reaction of aqueous solution of glycerol of certain concentration at the low temperature of 240 DEG C and high space velocity of 15h-1, the product acrolein and unreacted glycerol are separated, and thus carbon deposition of the catalyst can be well inhibited and unreacted raw materials can be recycled. By adopting the process, the carbon deposition of the catalyst can be greatly inhibited, so that the catalyst can maintain high activity in a long time. Meanwhile, the problem of low conversion rate of raw materials under the conditions can be solved due to separation of the product, and the process is efficient and environmentally friendly.

Description

technical field [0001] The present invention relates to the field of catalytic glycerin dehydration to produce acrolein. The specific method is to react glycerin aqueous solution under low temperature and high space velocity conditions in a fixed bed reactor, and separate the product acrolein from unreacted glycerin. Under this condition It can well inhibit the carbon deposition of the catalyst, and the activity of the catalyst will not decrease for a long time. Background technique [0002] Acrolein is an unsaturated aldehyde with high chemical activity and can be used to sterilize or synthesize important chemical intermediates. The traditional production process of acrolein is too dependent on the development of petroleum resources, and the preparation of acrolein by dehydration of biological glycerol is a green and efficient process method. [0003] At present, the dehydration of glycerol to acrolein is mainly carried out in homogeneous and heterogeneous systems. In the ...

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Problems solved by technology

[0004]Because of the homogeneous system of glycerol dehydration, there are problems such as harsh reaction conditions and the catalyst is easy to coke and cannot be recovered, so people turn the research direction to the heterogeneous reaction system , the currently reported heterogeneous reaction device for glycerin dehydration is mainly a fixed-bed reactor, and the catalysts used include solid acid, acidic molecular sieve and immobilized heteropolyacid, etc. For example, FR695931 reported that phosphate was immobilized on pumice Above, at 400-420°C, the yield of acrolein can reach 70%, but this result cannot be repeated after testing; US Patent No. 5,387,720 reports that using solid phosphoric acid as a catalyst, the conversion rate of glycerin can reach 100% at 340°C. %, the selectivity of acrolein reached 70.5%, but the activity of the catalyst decreased rapidly; Chinese patent CN 102267882 reported the use of immobilized acidic ionic liquid as catalyst, at 300°C and 6 h-1 Under optimal conditions, the selectivity of acrolein and the conversion rate of glycerin are both high. Although the catalyst has good activity, the carbon deposition of the catalyst is still serious after long-term use.

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