Synthesis Of A Diesel Fuel Cetane Number Improver-Cyclohexyl Nitrate

Emissions caused by incomplete combustion of diesel engines at this stage is still plagued by environmental pollution control. The most common method is to add cetane improvers to promote diesel full combustion. From this perspective, we research one kind of the cetane improver–the improvement synthesis of cyclohexyl nitrate.The existing synthesis of industrial cyclohexyl nitrate is use H2SO4 as catalyst under conditions of low temperature, added to the feedstock of cyclohexanol and 65% nitric acid,but the catalyst is strong corrosion, and the reaction need harsh conditions, and have the disadvantages of difficult to recover and exist factors of instability during the reaction.Considering many disadvantages of H2SO4 as catalyst, the subject choose the strong acid NKC-9 strong acid cation exchange resin as catalyst, and explore the catalytic synthesis of cyclohexyl nitrate is feasible and the viable optimal conditions. The subject innovation is the use of heterogeneous catalyst for the reaction to avoid the drawbacks of H2SO4 as catalyst,reduce the instability in the reaction process. Heterogeneous catalysts compared with conventional homogeneous catalysts because of easy separation and recovery, and the resulting "waste less" is more meet the advantages of green chemical requirements.This article describes the domestic and foreign research status of synthesis of cyclohexyl nitrate, and expounded in terms of the reaction mechanism, catalyst type, and other factors. In the early experiment preparation stage we conducted the preparation process of NKC-9 strong acid cation exchange resin, and we use acid-base titration to detect the resin acidity. In the exploratory phase of synthesis conditions, from experimental stability and controllability point consideration, we through single factor experiment to determine the roughly range of the main factors affecting proceed smoothly experiments. Three key factors were studied which were the ratio of acid to alcohol, the reaction temperature and the amount of catalyst the experiment used. And then determined the number of factors and the number of levels, whichwere needed to investigate in the orthogonal experiment. And by the orthogonal experiments determined the sort of various factors affecting the amount of the yield: experimental reaction temperature, the ratio of acid to alcohol, the amount of catalyst and the reaction time. The optimal reaction conditions for the experimental reaction are the temperature is 30 °C, the acid and alcohol molar ratio is 0.75:1, the reaction time is 100 min, the amount of catalyst is12.5%.After the study of NKC-9 strong acid cation exchange resin catalyst synthesis reaction,we investigated the effect of adding a secondary catalyst ferric chloride catalyst. On the basis of the experiments we have been carried out, we directed the orthogonal experiment, we found that the addition of ferric chloride assisted catalytic effect is not very obvious, which can only raise a small yield.By the orthogonal experiments determined the sort of various factors affecting the amount of the yield: the ratio of acid to alcohol, experimental reaction temperature, the amount of catalyst, the reaction time and the amount of ferric chloride. The optimal reaction conditions for the experimental reaction are the acid and alcohol molar ratio is 0.75:1, the temperature is 30 °C, the reaction time is 80 min, the amount of catalyst is 12.5%, and the amount of ferric chloride is 14.7%.