Isomerization of dimethylnaphthalene to produce 2,6- dimethylnaphthalene

摘要

The present invention relates to a method of preparing 2,6- dimethylnaphthalene from a feed stream that contains hydrocarbons which contain dimethylnaphthalene isomers. The method includes the following steps:PPI. distillation and concentration of the dimethylnaphthalene isomers from the feed stream, to form a dimethylnaphthalene fraction,P PII. isomerization of the dimethylnaphthalene fraction to enrich the dimethylnaphthalene fraction in 2,6-dimethylnaphthalene, to form a 2,6- enriched dimethylnaphthalene fraction,PPIII. purification of 2,6- dimethylnaphthalene from the 2,6-enriched dimethylnaphthalene fraction, PP wherein step II is conducted in the presence of a catalyst composition containing a synthetic zeolite characterized by an X-ray diffraction pattern including interplanar d-spacing (Å)PP12.36.+ - .10.4PP11.03.+-.0.2PP8.83.+-.10.14 PP6.18.+-.0.12PP6.00.+- .0.10P P4.06.+-.0.07PP3.91.+-.0.01PP3.42.+-. 0.06,PP wherein the purification includes crystallization under pressure.