| 摘要 |
2-chloro-methyl-pyridine hydrochloride is prepared in a solvent medium in the presence of an acid scavenger by partial chlorination. Resulting 2-chloro-methyl-pyridine is treated by hydrochloric acid. Based on the number of 2-methyl-pyridine mols present, 0.5-2 mols. pref. 0.8-1.0 mols Cl-gas is introduced. Chlorination takes place at 20-70 degrees C temp., pref. at 30-40 degrees C. The reaction mix. is cooled to 30 degrees C, and treated with at least a stoichiometric quantity of HCl. Solvent is recovered from the solvent phase and is reciculated. The pH of the aq. phase is set to a value of 3-4.5, using a base. The aq. phase contains a mixt. of chlorinated prods. These are septd. by solvent extraction. The aq. phase contains 2-methylpyridine HCl as the largest component. 2-methyl-pyridine is liberated by alkaline treatment extracted by solvent and returned to prodn. The aq phase is treated again with at least a stoichiometric quantity of HCl. The 2-chloro-methyl-pyridine-hydrochloride found in the aq. phase is dehydrated by evaporation and opt. recrystallised from ethanol. |
