Study On The New Method Of The Chloromethylation Of Aryl Hydrocarbon

Blanc chloromethylation is a very classical reaction, which is a very important method on inducting chloromethyl in aryl hydrocarbon. It has very comprehensive application on the synthesis of pesticide,medicament,dye,spicery and other fine chemicals. The chloromethyl can be turned into many other groups, such as -CH₂OH,-CHO,-CH₂CN,-CH₂NH₂,-CH₃,-CH₂R and so on, which will be easily preparared for many new ramifications.In this paper, the catalyst which consists of different concentration of H₂SO₄, HAc and the liquid Lewis acid, which was used to catalyze Blanc chloromethylation. The catalyst can reach a good control effect by changing the chroma and the proportion of these components of it, which will be behooved for catalysing on the chloromethylation of the different activated aryl hydrocarbon. The reaction selecti- vity can be greatly improved, the outgrowth decreased and the yield can be obviously improved. It can be used repeatedly and represent well recycling. So it overcome the insufficiency of the one-time deplete of the already chloromethylation catalyst, which decreased its disserve to our entironment and realized the friendly entironmental chloromethylation. To be different from the already chloromethylation catalyst, it has a certain amount of moisture wet, which will not produce huge amounts of doughtic cancerogenic chloromethyl methyl ether during and after the reaction.4,4'-bis(chrolomethyl)biphenyl, 1,4-bis(chloromethyl)benzene, 1,4-bis(chloro- methyl)-2,5-dimethylbenzene, 1,5-bis(chloromethyl)-2,4-dimethylbenzene, 4-(chlor- omethyl)-1,2-dimethylbenzene, 1,2-bis(chloromethyl)-4,5-dimethylbenzene, 5,8-bis( chloromethyl)-1,2,3,4-tetrahydronaphthalene, 3,3',5-tris(chlomethyl)-4,4'-bis(methy- l)biphenyl and 3,3', 5,5'-tetrakis(chloromethyl)-4,4'-bis(methyl)biphenyl were synth- esized by using this new catalyst. Results indicated that when the reaction temperature was 55～60℃, the reaction time was 12h, the catalyst which consists of the concentration of 80%H₂SO₄, HAc and Lewis acid, the amount of Lewis acid 0.15 mol(nLewis:nbiphenyl=1.5:1), yield of biphenyl chloromethylation product (4,4'-bis(chrolomethyl)biphenyl) can reach a maximum 85%. The results of benzene indicated that when the reaction temperature was 70℃, the reaction time was 8h, the catalyst which consists of the concentration of 80%H₂SO₄, HAc and Lewis acid, the amount of Lewis acid 0.1 mol(n Lewis : n benzene=1:1), yield of chloromethylation product (1,4-bis(chloromethyl)benzene) can reach a maximum 75%. The results of p-xylene indicated that when the reaction temperature was 40℃, the reaction time was 10h, the catalyst which consists of the concentration of 60%H₂SO₄, HAc and Lewis acid, the amount of Lewis acid 0.1 mol(n Lewis:nbenzene=1:1), yield of chloromethylation product (1,4-bis(chlormethyl)-2,5-dimethylbenzene) can reach a maximum 78.5%. The results of m-xylene indicated that when the reaction temperature was 35℃, the reaction time was 10h ,the catalyst which consists of the concentration of 60%H₂SO₄, HAc and Lewis acid, the amount of Lewis acid 0.1 mol(n Lewis: n benzene=1:1), yield of chloromethylation product (1,5-bis(chlorome- thyl)-2,4-dimethylbenzene) can reach amaximum 81.5%. Besides, The results of Blanc chloromethylation on o-xylene, 1,2,3,4-tetrahydronaphthalene and 4,4'-bis(m- ethyl)biphenyl were also good. The yields of chloromethylation product of o-xylene (contain 4-(chloromethyl)-1,2-dimethylbenzene and 3-(chloromethyl)-1,2-dimethyl- benzene) can reach a maximum 81.5%, the yield of another chloromethylation product of o-xylene (1,2-bis(chloromethyl)-4,5-dimethylbenzene) can reach a maximum 75.9%; the yield of chloromethylation product of 1,2,3,4-tetrahydro- naphthalene (5,8-bis(chloromethyl)-1,2,3,4-tetrahydronaphthalene) can reach a maximum 78.6%; the yield of chloromethylation product of 4,4'-bis(methyl)biphenyl (the product 3,3',5-tris (chlomethyl)-4,4' bis(methyl)biphenyl can reach a maximum 45.8% and the product 3,3', 5,5'-tetrakis(chloromethyl)-4,4'-bis(methyl)biphenyl can reach a maximum 31.9%. Calculate the conversion of raw material, selectiveity and yields of product to inspect the possible factor affecting the reaction and regularity of chloromethylation of benzene derivate catalyzed by such a catalyst. Screening the best efficiency catalyst that will be used in single factor experiment (contain reaction temperature, reaction time, catalyst and the cycle catalyzation of catalyst). Main products were compared with standard material, 1HNMR and 13CNMR were used to make sure the molecular structure. Among these compounds, 1,4-bis(chloromethyl)-2,5-dimethylbenzene,1,5-bis(chloromethyl)-2,4-dimethylben-zene,1,2-bis(chloro-methyl)-4,5-dimethylbenzene,5,8-bis(chloromethyl)-1,2,3,4-tet- rahydronaphthalene,3,3',5-tris(chlomethyl)-4,4'-bis(methyl)biphenyl and 3,3',5,5'- tetrakis(chloromethyl) -4,4'-bis(m- ethyl)biphenyl are new compounds.Besides, we tried to find out the cycle catalyzation of the catalyst, the results of the research indicated that the yield of chloromethylation of biphenyl, benzene, p-xylene, m-xylene, o-xylene, 1,2,3,4-tetrahydronaphthalene, and 4,4'-bis( methyl)biphenyl catalysed by it changed not so much during the repetition experim- ents, which demonstrated that the catalyst can be recycled and reused successfully for Blanc reactions of them.