Study On Preparation Of Vinyl Ether From Calcium Carbide And Fatty Alcohol

Calcium carbide was once the mother of organic synthesis.It reacted with water to generate acetylene,and then synthesized polyvinyl chloride,polyvinyl alcohol,1,4-butanediol,vinyl acetate and so on.In the 1960 s,the global petrochemical industry boomed,which led to the gradual shrinking of calcium carbide synthetic chemical routes.However,the resource endowment of my country’s rich coal,poor oil and little gas makes coal-to-calcium carbide and calcium carbide-acetylene route still play an important role in organic synthesis.Our country’s calcium carbide production continues to increase,reaching 27.58 million tons in 2020.Calcium carbide has long been used to produce downstream products from acetylene.Since acetylene has certain safety hazards in storage and transportation,and the downstream products are not rich enough,the direct use of calcium carbide as an acetylene source to prepare downstream products has become an increasingly popular research direction.The research group has done a lot of exploratory research on the direct reaction between calcium carbide and organic matter in the early stage,and found that the reaction of calcium carbide with methanol and ethanol can produce vinyl ether compounds,but the product yield is low and the process is not clear.In order to deeply explore the reaction between calcium carbide and fatty alcohols,the effect of reaction conditions on the product distribution and yield of the reaction between calcium carbide and various alcohols(methanol,ethanol,npropanol,isopropanol and n-butanol)was studied in detail.The main conclusions were as follows:(1)Reaction of calcium carbide and methanol indicated that the reaction time affects the product distribution,and acetylene is mainly generated in a short time.Extending the reaction time is conducive to the formation of methyl vinyl ether;low temperature is favorable for vinyl reaction,and the yield of methyl vinyl ether decreases slightly at high temperature.(2)The first-order kinetic model was used to obtain the rate equation for the synthesis of methyl vinyl ether from calcium carbide and methanol at225°C-300°C,where the activation energy Ea=49.73 k J/mol,and the preexponential factor A=3334.(3)Sodium methoxide,nickel carbonate and potassium carbonate have certain catalytic effects on the reaction of calcium carbide and methanol.When the reaction temperature is 190,only acetylene is generated without catalyst,but after adding sodium methoxide or potassium carbonate to the reaction system,the catalytic effect is obvious.The highest yield of methyl vinyl ether is 70%,and the optimum yield under the catalysis of nickel carbonate was 40%.(4)The results of the reaction of calcium carbide and ethanol to prepare ethyl vinyl ether show that when the reaction temperature is lower than275 °C,the temperature rise is conducive to the formation of ethyl vinyl ether.The longer the reaction time,the higher the yield of ethyl vinyl ether.The highest yield is 33.5%.The process is accompanied by the growth of the ethanol chain,and the temperature is higher than 275 °C,which is conducive to the formation of n-butanol.The reactivity of isopropanol is higher than that of n-propanol,and the temperature lower than 275 ℃ is favorable for the formation of propyl vinyl ether.