Application Of Additives In The Preparation Of Furfural By Hydrolysis Of Corncobs

Furfural is an important organic compound, which is widely used in drug synthesis, foodadditives, spices synthesis, synthetic resin, and many other fields. At present, the industrialproduction of furfural is a hydrolysis process which uses lignocellulosic biomass as rawmaterial and the sulfuric acid as catalyst. In this process, because of raw material’s incompletehydrolysis, side reactions, severe losses and waste of furfural, low refining rate of grossfurfural and so on. The “three wastes” pollution is serious which greatly restricts thedevelopment of furfural industry. This thesis focused on the side reactions which had greateffect on the yield in the preparation of furfural. The furfural yield was improved by addingpolymerization inhibitors to restrain the side reactions and optimizing sulfuric acid catalytichydrolysis process to strengthen the hydrolysis.The following innovative results were achieved:1、The industrial production process of furfural was simulated by injecting watercontinuously into the high pressure reaction kettle during the reaction. The effects of thesulfuric acid concentration, reaction temperature and hydrolysis time on the furfural yieldhave been studied. The results showed that under the conditions of reaction temperature180℃, sulfuric acid concentration0.5%, catalytic hydrolysis time3.5h, the furfural yield of70.3%was obtained, which is about10%~20%higher than that of the industrial productionprocess;2、Based on the analysis of the production mechanism of furfural, hydroquinone,diphenylamine, thiourea and triphenylphosphine as additives were chosen to restrain the sidereactions in the process. The results showed that all of the four additives can significantlyimprove the yield of furfural. When hydroquinone was added in the amount of0.25%of thetotal weight of corncob, the furfural yield was83%; When diphenylamine addition amountwas0.2%of the total weight of corncob, the furfural yield was80%; whentriphenylphosphine addition amount was0.25%of the total weight of corncob, the furfuralyield was86%; when thiourea addition amount was0.2%of the total weight of corncob, thefurfural yield was85%;3、The action mechanism of triphenylphosphine was preliminarily investigated. Thecompositions of the distillates, the waste water and furfural slag were analyzed using high performance liquid chromatography and gas chromatography-mass spectrometry (GC-MS).The results show that triphenylphosphine increases furfural yield but does not affect thecomposition of the distillates. As a desirable additive, triphenylphosphine has a goodapplication prospect in furfural production which uses lignicellulosic biomass as raw material.