Extraction And Degradation Of Lignin From Wheat Straw

As the population growth and industrial development,the resource consumption is increasing,it is urgently necessary to find new sources of energy to replace non-renewable,gradually depletion-able fossil energy,the renewable biomass energy has become one of the fastest growing alternative energy in the world,meanwhile the proportion of the usage of biofuels continues to increase.Biomass energy from renewable resources has been considered an alternative source of energy,and the growing contribution of biomass to the world energy also gives a new way to solve the problems such as global warming,the soaring fuel costs and environmental pollution.Lignocellulose is the main component of plant cell walls and is also one of the most abundant renewable resources on earth.Because lignin is one of the most abundant components in the lignocellulosic biomass besides polysaccharides,so it is important to make rational utilization of lignin,and degradation of it into phenolic compounds will gradually become the research focus in this field.The main purpose of this article research is that through the two-step alcoholysis-hydrogen solution method to extract the wheat straw lignin degradation.First step is alcoholysis to cleave the C-O bonds of lignin effectively.Through analysis the effect of temperature,time,liquid-solid ratio of NaOH and the types of alcoholysis reagent.The second step is hydrogenolysis to further reduce substituents on the benzene ring.Through analysis the effect of temperature,time,types of hydrogenation catalyst and the amount of hydrogenation catalyst.The optimum process conditions of the degradation of lignin is alcoholysis conditions: 200 °C,reaction time for 6 h,methanol volume fraction of 50%.Hydrogenolysis solution conditions: 120 °C,reaction time for 3 h,atmosphere: hydrogen,atmosphere at 2 MPa,5 to 1 NaOH to Pd/C catalyst ratio.Under the condition of the process,the degradation of lignin product yield is 47%.The product of the lignin degradation can be examed by GC-MS,when the temperature is controlled at 160°C,the content of 4-vinyl phenol up to 24.53%;when the temperature controlled at 200°C,the content of phenol up to 8.89%,he content of 4-ethyl phenol up to 27.85%,he content of guanaco up to 10.37%.These compounds are important industrial raw materials,this experimental process is important to the production of fine chemical products research.