摘要 |
<p>Preparation of high yields of mixtures rich in polychlorinated pyridines by maintaining a chlorine to beta-picoline weight ratio of greater than about 5:1 when reacting chlorine and beta-picoline or beta-picoline hydrochloride non-catalytically in the liquid phase at temperatures of at least about 190oC, the reactants being contained in a well mixed diluent producing less than one mole of hydrogen chlorine per mole of diluent by reaction with the chlorine in the indicated temperature range. Chlorination of the beta-picoline or beta-picoline hydrochloride in a primary reactor (R1) is followed by selective further chlorination thereof in finishing reactor means (R3A and R3B) at a temperature of at least about 190oC to obtain high yields of desired final products useful as intermediates in the formation of herbicides and the like. Like further chlorination to obtain such final products is also applicable to mixtures rich in monochloro- and dichloro-3-trichloromethyl pyridines produced by other processes. </p> |