Study On The Basic Problem Of Lignin Separation From Grasses

Green chemistry grown up in recent decades, is a measure to eliminate pollution from the source, which had solved the chemical industry pollution to the environment effectively and achieved sustainable economic and social development. With the overexploitation of non-renewable resources, the research and development of renewable resources had been paid more and more attention gradually. The plant is the most abundant recycle resources on the planet, most of them are untapped every year. The Utilization rate of plant is low, which result in a large waste of resources. As the major component of plant, lignin is the second most abundant recycle resource, and the only renewable aromatic compounds that occur in nature. With acid, alkali or organic solvent solution as a solvent to separation lignin, the solvent mostly have serious pollution, high cost and low recovery faults.Here, the processes and mechanis of lignin separation from grasses has been fully investigated, including microwave radiation lye cooking pulping, several ionic liquid cooking pulping, and the reaction kinetics of delignification.Firstly, pulp cooking condition of wheat straw in different traditional alkaline solution including NaOH solution and NaOH-NH4OH solution was tracked. When microwave-assisted the pulping, short reaction time and low temperature can achieve good removal effect and smaller reaction activation energy.Secondly, pulp cooking in four ionic liquids were carried out, including sulfonate triethylamine ionic liquids([HN+-(C2H5)3]HSO4-)、alcohol amine alkaline ionic liquids ([NH-(C2H4OH)3]+) and neutral ionic liquids ([Emim]Br)by traditional heating, alkaline ionic liquids ([Emim]OH) with microwave heating. Experiments of different solid-liquid ratio、temperature and time were carried out. Compared with the traditional method, ionic liquids as solvents have excellent chemical and thermal stability, and good solubility. Meanwhile, the reaction process does not generate waste liquid, the ionic liquid can be recycled recycling, the ionic liquid recycled back can be repeatedly used many times, the effect of dissolved basically unchanged. Recovery of ionic liquid can be repeatedly used many times, the effect of dissolution basically unchanged. The ionic liquid combined with microwave technology has high-speed, high efficiency, energy-saving, environmentally friendly and other features. The research on the kinetics of lignin dissolution process can control the reaction easier.The microwave radiation reaction has smaller activation energy when compared each cooking experiment data. The different ionic liquid pulping data had shown neutral ionic liquid and acidic ionic liquid cooking better.