Optimization of distillation operation parameters of high purity 2,3-dichloro-5-trifluoromethylpyridine

2,3-Dichloro-5-trifluoromethylpyridine is rectified by vacuum distillation with high efficient packed tower with θ filler,the product purity is over 99%,99.3% at instant,the yield is over 75%.Through the study of multivariable batch distillation process,the optimized operation parameters were obtained,the pressure is 10kPa～30kPa,the reflux ratio is 4～1 2,The experimentation indicated that multivariable batch distillation process could improve the yield.