Application Of Micro Channel Reactor In Nitrification Reaction

Nitration reaction occupies an important position in the synthesis of organic compounds occupies, but there are a lot of problems with it, such as safety production problem, regioselectivity problems. So we introduced the micro channel reactor into the nitration reaction, aimed to reach safe production of the nitration reaction and improve the selectivity of the target product by use of the micro reactor’s unique advantages.Fatty alcohol and simple aromatic nitration were studied, we used 2-ethyl-1-hexanol and o-xylene as the major nitrification, the micro channel reactor was applied to the synthesis of the nitrate ester and aromatic nitro compounds.(1)With mixed acid of nitric acid and sulfuric acid as nitrating agent, the optimum reaction conditions in micro channel reactor was obtained through investigating the influences of reaction temperature, mixed acid ratio, concentration of nitric acid, molar ratio of nitrate and 2-ethyl-1-hexanol and the use of different solvents on the nitration. The experimental results show that, at the room temperature, with n(HNO3):n(H2SO4)=1:2.5, nitrate concentration was 55%, n(HNO3):n(2-ethyl-1-hexanol)=1.4, the purity of 2-ethylhexyl nitrate as high as 99.6%, the yield reached 99.5%. We discussed the reaction mechanism of nitrate by mixed acid in micro channel reactor.(2) O-xylene was used as the major research object, from the nitration system such as HNO3、HNO3-H2SO4 and N2O5, we selected the green nitration system N2O5 as nitrating agents in the end, systematically studied on the nitration process of o-xylene in the micro channel reactor, based on the factors such as reaction temperature, reaction time. The best nitration process of o-xylene in the micro channel reactor as follows:o-xylene and N2O5 molar ratio of 1:1.2, the reaction temperature was 30℃, residence time was 29.6, the solvent we used the CH3CN, at this time the conversion of o-xylene was 87.6%, and the selectivity of the 4-nitro-o-xylene was more than 57.3%.(3)The micro channel reactor was applied to the nitration of other aliphatic alcohols and simple aromatic hydrocarbons. Compared with conventional reactors, it was found that both the conversion rate and the selectivity were significantly improved.