Study On Technology Of Furfural Preparation From Xylose Dehydration

Furfural is an important chemical material and widely used in many fields such as petroleum refining, petrochemical industry, pharmaceuticals industry, food industry, synthetic rubber and synthetic resin. But its technology is out-of-date in our country. The mostly employed technology in industry is one-step process, which leads to a lower yield about 50% and severe wastes. Compared with one-step process, two-step process is characterized by many merits such as higher yield and sufficient utilization of raw materials. In fact, the first step of two-step process, i.e. production of pentose from pentosan by hydrolysis, is developed, but as the second step, the technology of production of furfural from pentose is under-developed and needs further researches. In this thesis, the effects of reaction temperature, catalyst amount and the initial concentration of xylose on the yield of furfural during production of furfural from xylose dehydration were investigated. Acetic acid, sulfuric acid and phosphoric acid were used as catalyst in the experiments. When acetic acid and phosphoric acid were used as catalysts, the pure xylose and water were adopted as reactant and solvent respectively. Whereas sulfuric acid was used as catalyst, the raw material was pentose solution hydrolyzed from corn core.As an intermittent reaction, the experiments were conducted in autoclave. In the experiments all the raw materials were put into the autoclave and during the reaction process the azeotropic mixture of furfural and water in vapor phase was removed from the systems and collected. In comparison with the industrial process, which added steam into the reactor during the furfural production, the furfural can turn into vapor phase more immediately and completely in our experiments.The experiments results show that with the reaction temperature increase, furfural production rate and agglomeration increase and the amount of catalyst and its effect on furfural yield decrease, at the same time, the yield of furfural increases and then decreases. With the amount of catalysts increase, agglomeration increase whereas the yield of furfural increases and then decreases. With the initial concentration of xylose increase, the amount of catalyst increases whereas the yield of furfural increases and then decreases. With the acidity of catalysts from acetic to sulfuric acid increase, the reaction temperature decreases due to increase in catalysis.When acetic acid, phosphoric acid, sulfuric acid were used as catalyst, the maximum yield of furfural were 81%, 68% and 62% respectively under our...