Chloromethylation Reaction Catalysted By Ionic Liquids For Ethyl Benzene, 1,2-Xylene And Anisole

Today, "Green Chemistry" is already accepted as one of the most important Scintific fields in 21 century, which is the most fundamental science method being prevented from contaminating. Room temperature ionic liquid as one kind of late-model green solvents and catalytic materials, broadly applicated in many chemical industry fields because of its environmental friendship and architectural plasticity, has long been under people during the past few years.In this paper, 12 kinds of ILs were synthesized to catalyze Blancchloromethylation on ethyl benzene, 1,2-xylene, anisole and pyridine. Product quantitation adopted intemal standard curve method whose accuracy rating was good. Calculate the conversion of raw material, selectivity and yields of product to inspect the possible factor affecting the reaction and regularity of chloromethylation of benzene derivate catalyzed by ionic liquids. Screening the best efficiency ionic liquid that will be used in single factor experiment (contain the contents of ionic liquid, reaction temperature and reaction time). Results indicated that when the reaction temperature was 90℃, the reaction time was 4 h, the content of catalyst [C₈mim] Br was 10%, yields of ethyl benzene chloromethylation products (contain 4-ethylbenzyl chloride and 2-ethylbenzyl chloride) can reach a maximum 54.08%. The results of 1,2-xylene chloromethylation indicated that when the reaction temperature was 70℃, reaction time was 10h, the content of ionic liquid [C₁₂mim]Br was 4%, yield could reach a maximum 89.86%, including 57.51% 1-chloromethyl-3,4-dimethylbenzene and 24.15% 1-chloromethyl-2,3-dimethylbenzene. Main products were compared with standard material and GC-MS was used to make sure the molecular structure. We trid to fred out the cycle catalyzation of ionic liquid and the results were that the yield of chloromethylation of ethyl benzene catalysed by [C₈mim]Br and chloromethylation of 1,2-xylene catalysed by [C₁₂mim]Br changed little during the 6 times repetition experiment.The chloromethylation activity of different substrates are different, we've tried anisole and pyridine catalyzed by [C₁₂mim]Br and the result was that the activity of anisole was high. Tested by MS, we found that the products were complicated, including benzene, 1-(chloro-methyl)-3-methoxyl; benzene, 1-bromo-4-(chloromethyl)-; benzene, 1-bromo-2-(bromome-thyl);benzene, 1-methoxy-2-[(4-methoxyphenyl) meth-yl]- and etc.;pyridine couldn't be chloromethylated using catalyst [C₁₂mim]Br.