| 摘要 |
PURPOSE:To obtain the title compound by simultaneously performing the transmethylation of naphthalene using a methylbenzene and disproportionation of the methylbenzene and by making the disproportionation of the monomethylnaphthalene separated followed by transmethylation and then isomerization. CONSTITUTION:(1) Transmethylation, i.e. methylation of naphthalene using a xylene, and disproportionation of the xylene are performed simultaneously, and (2) the resulting reaction mixture is separated into a benzene-toluene fraction, xylene-trimethylbenzene-tetramethylbenzene fraction, unreacted naphthalene, monomethylnaphthalene (MMN), dimethylnaphthalene (DMN), and trimethylnaphthalene (TMN). (3) DMN production by disproportionation and/or transmethylation of the MMN in the presence of the DMN and TMN and isomerization of the DMN are made simultaneously followed by separation of DMN, which is then mixed with the DMN in the step (2) followed by separation and recovery of the objective 2,6-DMN. The present method will decrease methyl group loss and produce the objective compound in high purity. |
