Research On Hydrothermal Transformation Of Alkali Lignin Of Bamboo Willow Tree

With the construction of human ecological civilization,environmental protection needs more and more attention.The original energy release a lot of carbon dioxide,dust and a small amount of nitrogen and sulfur compounds,which undermine air quality,reduce the quality of the human lives.Therefore,we urgently need to find a new,non-polluting,renewable,wide variety of sources of raw materials of new energy,utilizing these materials to replace the old energy system.In this research,the chemical structure of alkali lignin was characterized by NM and infrared IR.However,the hydrothermal transformation experiment of black liquor and four kinds of catalysts were studied.The lignin products are variety of aromatic phenolic compounds.The influence of the reaction temperature as well as the reaction time on the distribution of the product was studied by the hydrothermal transformation experiment without adding the catalysts.The small molecular substances were produced by the hydrothermaldegradationofthelignin,includingphenol,guaiacol,2,6-dimethoxyphenol,3-methoxy-1,2-benzenediol,vanillin,3,5-dimethoxy-4-Benzyl,alcohol,2-methoxy-4-propylphenol,3-hydroxy-4-methoxyphen ylethanone.The temperature is in range of 280? to 330? and the reaction time was extended to 30min-70min.The optimum temperature of the crude oil is about 300? and bio-oil the best reaction time is 60 min,the yield of 93%.In addition,the reaction of adding ethanol,bio-oil with the increase in ethanol yield decreased linearly.From the quantitative analysis of various components of biological oil,it was found that guaiacol,phenol,2,6-dimethoxyphenol quantitative value of 310? is the optimal value.The quantitative range of 3-methoxy-1,2-benzenediol varies little with temperature.From the reaction time,the change of the content of phenol and 3-methoxy-1,2-benzenediol over time was very small,and the content of the two was basically fixed at 0.20 mg/g.Guaiacol at 60 min has an optimum value of 1.7908 mg/g,2,6-dimethoxyphenol at 60min has an optimal value of 2.0237 mg/g.Bio-carbon infrared analysis shows that the temperature changes have no effect on the bio-carbon structure,but the reaction time is prolonged and the fraction of the benzene ring compound increases.The addition of the catalyst Pt/C,alkali lignin degradation product contains the small molecular weight 3-furancarboxaldehyde produced by the oxidized cleavage of the alkali lignin benzene ring structure and the alkali lignin hydrothermal conversion product without the addition of the catalysts.5-methyl-2-furanaldehyde was not detected at 220?,The content remained at 0.06 mg/g.The quantitative value of phenol at 220? is 0.0470 mg/g,and after 250?,the content is stable at 0.15 mg/g.The content of guaiacol increased with increasing temperature,and the best value at 280? was 0.3932mg/g.2,6-dimethoxyphenol with the temperature increases,its content is also gradually increased at 280? to reach the maximum 0.50 mg/g.The addition of the catalyst Pd/C,the alkali lignin degradation product component is similar to the addition of Pt/C degradation product.From the quantitative analysis of Pd/C bio-oil products,The content of guaiacol gradually increased with the increasing of temperature,reaching a maximum of 3.37 mg/g at 280?.2,6-dimethoxyphenol content is relatively high,at 300? reached a maximum of 21.26 mg/g.4-hydroxy-3,5-dimethoxy benzaldehyde and 4-hydroxy-3,5-dimethoxyacetophenone content increased first and then decreased with the increase of temperature,Dimethoxybenzaldehyde content reached a maximum of 7.46 mg/g at 260?.The optimum temperature of 4-hydroxy-3,5-dimethoxyacetophenone was 280? and the maximum was 3.85 mg/g.Addition of catalyst Pd-Ru/C,the alkali lignin degradation product component is similar to the hydrothermal conversion reaction product without the addition of the catalyst.From quantitative analysis of the product,2,6-dimethoxyphenol and guaiacol contain the amount increasing with the increase of temperature,2,6-dimethoxyphenol reached a maximum of 19.70 mg/g at 300?,guaiacol reached a maximum of 5.54 mg/g at 300.The content of 4-hydroxy-3,5-dimethoxybenzaldehyde increases first and then decreases with increasing temperature,the optimal temperature is 280?.There was no significant differences between the content of 4-hydroxy-3,5-dimethoxyacetophenone and the temperature change.The addition of Pt/Al₂O₃,the alkali lignin degradation product component is similar to the hydrothermal conversion reaction product without the addition of the catalyst.Quantitative analysis of the product shows that 2,6-dimethoxyphenol and guaiacol content with the increase of temperature gradually increased,guaiacol content at 300? reaches the maximum 5.64 mg/g,The maximum content of 2,6-dimethoxy benzenephenol is 21.05 mg/g at 300?.4-hydroxy-3,5-dimethoxybenzaldehyde decreases with increasing temperature at a maximum of 2.26 mg/g at 240?.4-hydroxy-3,5-dimethoxyacetophenone gradually increased with increasing temperature and reach the maximum value 8.99 mg/g at 240?.