Study On A New Technology Of Synthesis Of Mesitylene From Pseudocumene

In this paper, a new process was developed which can be usedto produce high-pure 1,3,5-trimethylbenzene(mesitylene) from 1,2,4-trimethylbenzene(pseudocumene). The technique had isomerizationof 1,2,4-trimethylbenzene and precise distillation as a union, whichis unique and feasible . The catalyzed isomerization without the present of hydrogenoccurred over M-2 composited mordenite in the MR-80 isothermalintegrating tube reactor, which use pseudocumene as raw material. Theeffects of reaction temperature, pressure and weight space velocity onthe catalytic activity were investigated. The experimental results showedthat at the reaction conditions of 340℃-360℃ ,2.5MPa, 1.2-1.4(v./v./hr ),the percent conversion of pseudomene was 39.32% with selectivity ofmesitylene 49.57% and the percent productivity of mesitylene was21.85%. The catalyst had high catalytic activity and selectivity . Because of the components of C₉ aromatic hydrocarbons thatcontained o-ethylmethylbenzene were complex and were mostly isomers,separation of mesitylene was difficult. Pseudocumene was converted tomesitylene with elimination of o-ethylmethylbenzene by isomerization.By means of precise distillation mesitylene was separated from thereaction mixture as much as possible with high purity. The separationprocess of mesitylene was simulated by the way of PROâ…¡. The resultsshowed that high-pure mesitylene whose purity's 98.97% and recycledpsedocumene whose purity's 90.72% were attained in the three-towerprocess.The purity of mesitylene has exceeded the industrycriterion(≥98.5%). At the same time, recycle feed of pseudocumenemade the productive cost much lower. The once-through productivity ofmesitylene was up to 17.25%, and the total productivity was up to40.41%.The once-through conversion of pseudocumene reached 42.52%,and the total conversion was up to 99.63%. This new method ofproduction of mesitylene was theoretical and applicable.