Method for preparing monophenol compounds through microwave depolymerization of lignin

A technology of monophenolic compounds and lignin, which is applied in the preparation of organic compounds, chemical instruments and methods, organic chemistry, etc., can solve the problems of low degradation efficiency, high cost input, and low conversion product yield, and improve efficiency And conversion rate, collection efficiency improvement effect

Active Publication Date: 2017-11-10
SHAANXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

A certain degree of degradation of lignin can be achieved by means of thermochemical conversion. However, at present, there are problems such as low degradation efficiency, serious charring phenomenon, low conversion product yield, and difficult product collection, which seriously restrict lignin. Efficient transformation and utilization of nutrients
At present, most of the researches realize the degradation of lignin under high pressure, high temperature and a large amount of hydrogen atmosphere, but the high cost input and the unsatisfactory product quality restrict the development of technology

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Taking the alkali lignin raw material as an example to introduce the implementation process of the present invention is as follows:

[0035] Mix 10g of alkali lignin (particle diameter 0.2-0.5mm, water content 8%) with 5g nano-silicon carbide particles (particle diameter 0.1-0.45mm) and perform microwave depolymerization reaction. In the microwave depolymerization reaction, a mixture of 100mL / min nitrogen, 1mL / min hydrogen and 10mL / min methanol was continuously introduced to start the microwave depolymerization reaction. The microwave depolymerization reaction conditions were microwave frequency 2.45GHz, microwave power 600W, heating temperature 500°C, reaction time 8 minutes. The thermal cracking vapor generated by microwave depolymerization is cooled at a condensation temperature of 1°C to obtain a solvent-based thermal cracking liquid. The solvent-based pyrolysis liquid is subjected to vacuum distillation, the vacuum distillation temperature is 20°C, and the relativ...

Embodiment 2

[0037] Taking the pyrolysis lignin raw material as an example to introduce the implementation process of the present invention is as follows:

[0038] Mix 10g of pyrolytic lignin (particle size: 0.05-0.1mm, moisture content: 3%) with 10g of α-silicon carbide particles (particle size: 0.45-1.0mm), and carry out microwave depolymerization reaction. In the microwave depolymerization reaction, a mixture of 300mL / min nitrogen, 3mL / min hydrogen and 150mL / min acetaldehyde was continuously introduced to start the microwave depolymerization reaction. The microwave depolymerization reaction conditions were microwave frequency 2.45GHz, microwave power 1200W, heating The temperature was 650°C, and the reaction time was 5 minutes. The thermal cracking vapor generated by microwave depolymerization is cooled at a condensation temperature of 5°C to obtain a solvent-based thermal cracking liquid. The solvent-based pyrolysis liquid is subjected to vacuum distillation, the vacuum distillation t...

Embodiment 3

[0040] Taking the lignosulfonate raw material as an example to introduce the implementation process of the present invention is as follows:

[0041] 10 g of lignosulfonate (0.1-0.3 mm in particle size, 5 percent moisture content) and 8 g of β-silicon carbide particles (0.45-0.6 mm in particle size) were uniformly mixed for microwave depolymerization. In the microwave depolymerization reaction, a mixture of 200mL / min nitrogen, 2mL / min hydrogen and 50mL / min methyl formate was continuously introduced to start the microwave depolymerization reaction. The microwave depolymerization reaction conditions were microwave frequency 2.45GHz, microwave power 1000W, The heating temperature was 550° C., and the reaction time was 6 minutes. The pyrolysis vapor generated by microwave depolymerization is cooled at a condensation temperature of 3°C to obtain a solvent-based pyrolysis liquid. The solvent-based thermal cracking liquid is subjected to vacuum distillation, the vacuum distillation tem...

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Abstract

The invention discloses a method for preparing monophenol compounds through microwave depolymerization of lignin. The method comprises the following steps: uniformly mixing, by mass, 10 parts of lignin and 5-10 parts of silicon carbide particles, and placing the obtained mixture in a microwave depolymerization reaction environment; continuously introducing a carrier gas and reaction gas mixed gas into the microwave depolymerization reaction environment to start a microwave depolymerization reaction; cooling pyrolysis gas generated during the microwave depolymerization reaction to obtain a solvent-based pyrolysis liquid; and carrying out reduced pressure distillation on the solvent-based pyrolysis liquid until no distillate is distilled off in order to obtain an undistilled component which is the monophenol compounds. The method greatly improves the yield of the monophenol compounds by changing the reaction atmosphere, and provides an important technical support for the high-efficiency conversion of the lignin into the monophenol compounds.

Description

technical field [0001] The invention belongs to the technical field of biomass energy, and in particular relates to a method for preparing monophenolic compounds through microwave depolymerization of lignin. Background technique [0002] Lignin is one of the important components of biomass, and it is a renewable carbon source second only to cellulose in abundance on earth. At present, the source of lignin is mainly industrial lignin, which is a by-product of the pulp and paper industry. The amount of lignin from the paper industry in the world reaches more than 50 million tons every year. The value of lignin is very low, and it is urgent to find a new way of high-value utilization of lignin. [0003] Lignin has both carbon chains and aromatic rings in its structure, and is connected with methoxyl groups (-OCH 3 ), hydroxyl (-OH), carboxyl (-CO) and other active functional group structures, it is an ideal raw material for the production of high-value fine chemicals such as ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C37/52C07C39/00
CPCC07C37/52C07C39/00
Inventor 王文亮李新平侯青青
Owner SHAANXI UNIV OF SCI & TECH
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