Study On Calcium Carbide Used In Acetone Condensation And Aromatization Reaction

Organic resources such as coal and biomass can directly generate oil,gas or chemicals through pyrolysis and hydroliquefaction.The solid residual coke and calcium oxide generated by the above reactions generate calcium carbide through oxythermal or electrothermal methods.Its main use is hydrolysis to acetylene gas,acetylene further converted into high value-added chemicals,such as polyethylene(PE),polyvinyl chloride(PVC),vinyl acetate and so on.However,acetylene is flammable and explosive,which brings great hidden dangers to safe production.Therefore,directly using the in-situ reaction of alkynyl ions in calcium carbide to prepare pure chemicals has become a research hotspot in the application field of calcium carbide.In the preliminary work of this research group,it was discovered that calcium carbide not only catalyzes the condensation of acetone to form isophorone(IP),but also participates in the subsequent aromatization reaction as a reactant to form methyl naphthalene compounds.However,multiple aromatization reactions are carried out in the reaction system at the same time,and there are too many kinds of products,resulting in low yield and selectivity of a single product.Therefore,in order to deeply explore the application potential of calcium carbide in acetone condensation and aromatization reactions,this paper focuses on the reaction behavior of calcium carbide and acetone at different temperatures,and further investigates the influence of 33,6,8-Tetramethyl-3,4-Dihydronaphthone(3,3,6,8-TMNO),aromatic compounds and IP yield factors,draw the following conclusions:(1)Calcium carbide acts as a basic catalyst,dehydrating agent and reactant in the condensation and aromatization of acetone.On the one hand,calcium carbide catalyzes the aldol condensation reaction of acetone to generate IP;on the other hand,calcium carbide participates in the aromatization reaction of IP to generate methylbenzene compounds,methyl naphthalene compounds and 3,5-dimethylphenol.The optimal reaction temperature to produce 3,5-dimethylphenol is 300℃,and the highest yield is 14.8%.When the reaction temperature is 400℃,the total yield of the liquid target product is 52.3%.(2)The best yield of IP is 34.1%.Low temperature is conducive to the self-condensation of acetone to form IP,and reducing the particle size of calcium carbide is conducive to increasing the rate of acetone aldol condensation reaction and shortening the reaction time to obtain the best yield of IP.When the molar ratio of acetone to calcium carbide is low,calcium carbide is excessive,strong catalytic activity and reaction activity,which is conducive to the further conversion of IP to 3,3,6,8-TMNO.When the molar ratio of acetone to calcium carbide is high,it is conducive to regulating the reaction at the stage of condensation of acetone to produce IP,thereby improving The selectivity and yield of isophorone.(3)The best yield of 3,3,6,8-TMNO is 30.1%.The formation of 3,3,6,8-TMNO is the result of the joint reaction of acetone,IP and calcium carbide.Increasing the mass concentration of IP in the reaction system is beneficial to increase the yield of 3,3,6,8-TMNO.