Study On The Purification Of 1, 2, 3-trimethylbenzene

Hemimellitene, also named 1,2,3-trimethylbenzene, is widely used in producing aniline dye, alkyd resin, polyester resin and Trihemimellitic acid and so on. But now, hemimellitene, which is mostly from the solvent oil of by-product of pseudocumene, is often used as a component to gasoline additive or as general solvent for its low purity. The aim of this article is to gain high-purity hemimellitene. The results of experiments provide the fundamental data for industry manufacture.This article develops advanced methods to separate hemimellitene from the solvent oil 190#. The results from GC/MC/DS analysis demonstrate that most of the components are C9 and C10 aromatics isomers which have little relative volatility. And It also shows that the key point of purifying hemimellitene was to separate it from indane whose boiling point is very close to.According to the former result, the vacuum batch distillation is adopted to purify the hemimellitene. In order to separate effectively, the design of process parameters for distillation column is indicated. The minimum theoretical plate number, minimum reflux ratio and total reflux time are estimated with shortcut calculation method in this paper.Solvent oil 190# is purified by vacuum batch distillation. On the premise of strict control of other conditions, the impact of reflux ratio on product purity and yield is focused on during the distillation. After 2 rectifications, product purity is up to 74.7% and yield 31.4% by introducing variable reflux ratios which is set as 4 during the initial produced stage and as 20 during the late produced stage.