Technology for preparing micro-molecular phenolic compound through microwave reinforced continuous degradation of lignin in hydrogen donor

Abstract

The invention discloses a technology for preparing a micro-molecular phenolic compound through the microwave reinforced continuous degradation of lignin in a hydrogen donor. The technology comprises the following steps: 1, continuously adding lignin to a microwave reinforced screw rod continuous degradation reacting device through a solid charging system, continuously adding the hydrogen donor and a catalyst to the continuous degradation reacting device through pumps, and carrying out a continuous degradation reaction of lignin at 150-200DEG C for 10-40min; 2, neutralizing degradation products in a neutralization pool in a degradation product separation device with an aqueous solution of NaOH, allowing the neutralized degradation products to enter a primary settling pool and a secondary settling pool, mixing lower-layer products of the primary settling pool and the secondary settling pool, filtering to obtain a water-phase product, using hydrochloric acid in an acidifying pool to adjust the pH to 2-3 in order to obtain the micro-molecular phenolic compound; and 3, filtering a used hydrogen donor which is the upper-layer product of the secondary settling pool, and regenerating in a Pd / C catalytic fixed bed hydrogenation device to obtain a regenerated hydrogen donor for cycle use. The technology which adopts continuous operation enables the treatment amount to be large and is suitable for the large-scale industrial application.

Description

technical field [0001] The invention relates to a process for preparing small-molecular phenolic compounds through continuous degradation of microwave-enhanced lignin in a hydrogen-donating agent. Background technique [0002] Lignin is a precious resource endowed by nature to human beings. It is the third natural organic matter after cellulose and chitin. It is estimated that 150 billion tons of lignin can be produced by plant growth in the world every year. Lignin is an aromatic polymer compound composed of phenylpropane structural units connected by ether bonds and carbon-carbon bonds. The three basic phenylpropane structural units are guaiacylpropane, syringylpropane and p-hydroxybenzene propane, as shown in the molecular formula. Therefore, lignin is the only raw material from which renewable aromatic compounds can be obtained from natural resources. The effective utilization of lignin will achieve huge economic and social benefits in industries such as agriculture, f...

AI Technical Summary

Problems solved by technology

Although the hydrogenolysis technology of solid acid and hydrogen donor can be used to degrade lignin to obtain higher yields of phenolic compounds, there are still problems such as high reaction temperature, long reaction time, discontinuous preparation process, and high energy consumption. There is still a considerable distance from large-scale industrialization

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