| 摘要 |
PURPOSE:To obtain the aimed compound 2,5-dihalogenated toluene useful as a raw material for medicines and agricultural chemicals, etc. advantageously in high selectivity, by halogenating a 2-halogenated toluene in the presence of zeolite L as a catalyst. CONSTITUTION:The 5-position of a 2-halogenated toluene is selectively and efficiently halogenated in the presence of zeolite L. The above-mentioned method has very high effect as follows; Not only the production of the aimed compound 2,5-dihalogenated toluene is improved but also the production of trihalogenated toluenes is reduced to 4-5% even on increasing the rate of reaction to 95- 96%. Thus, the yield of the aimed compound is improved. The reaction and post- treatment operation is easy, and the catalyst can be reused, etc. The zeolite L used in this method is a crystalline aluminosilicate having 4-8mol ratio (Al2O3/ SiO2) between Al2O3 and SiO2, contains usually potassium as an ion exchangeable cation and may further contain another cationic component. |
