Process for the preparation of 2,6-dimethylnaphthalene using a MTW zeolitic catalyst

A process for preparing 2,6-dimethylnaphthalene which comprises

• 1) reacting, under at least partially liquid phase conditions, in the presence of a zeolite having a MTW structure and optionally a methylating agent, a naphthalene hydrocarbon selected from the group consisting of naphthalene, methylnaphthalenes, dimethylnaphthalenes, trimethylnaphthalenes, tetramethylnaphthalenes, pentamethylnaphthalenes, hexamethylnaphthalenes, and their mixtures with one or more benzene hydrocarbons selected from the group consisting of benzene, toluene, xylenes, trimethylbenzenes, tetramethylbenzenes, pentamethylbenzene, and hexamethylbenzene to produce a product;
• 2) separating the product obtained in step (1) into fractions comprising (a) a fraction containing benzene aromatic hydrocarbons, naphthalene and methylnaphthalene, (b) a fraction containing dimethylnaphthalenes and (c) a fraction containing polymethylnaphthalenes;
• 3) separating fraction (b) into a fraction containing 2,6-dimethylnaphthalene and a fraction (d) containing 1,5 and/or 1,6-dimethylnaphthalenes, optionally mixed with other isomers of dimethylnaphthalene;
• and
• 4) feeding fractions (a), (c) and (d) to step 1).

A process for preparing 2,6-dimethylnaphthalene which comprises

• 1) reacting, under at least partially liquid phase conditions, in the presence of a zeolite having a MTW structure and optionally a methylating agent, a naphthalene hydrocarbon selected from the group consisting of naphthalene, methylnaphthalenes, dimethylnaphthalenes, trimethylnaphthalenes, tetramethylnaphthalenes, pentamethylnaphthalenes,hexamethylnaphthalenes, and their mixtures with one or more benzene hydrocarbons selected from the group consisting of benzene, toluene, xylenes, trimethylbenzenes, tetramethylbenzenes, pentamethylbenzene, and hexamethylbenzene to produce a product;
• 2) separating the product obtained in step (1) into fractions comprising (a) a fraction containing benzene aromatic hydrocarbons, naphthalene and methylnaphthalene, (b) a fraction containing dimethylnaphthalenes and (c) a fraction containing polymethylnaphthalenes;
• 3) separating fraction (b) into a fraction containing 2,6-dimethylnaphthalene and a fraction (d) containing 1,5 and/or 1,6-dimethylnaphthalenes, optionally mixed with other isomers of dimethylnaphthalene;
• 4) reacting fractions (a), (c) and (d), optionally enriched with naphthalene and/or methylnaphthalene, under at least partially liquid phase conditions, in the presence of a zeolite having a MTW structure, with one or more benzene hydrocarbons selected from the group consisting of benzene, toluene, xylenes, trimethylbenzenes, tetramethylbenzenes, pentamethylbenzene, and hexamethylbenzene.

A process for preparing 2,6-dimethylnaphthalene which comprises

• 1) reacting, under at least partially liquid phase conditions, in the presence of a zeolite having a MTW structure and optionally a methylating agent, a naphthalene hydrocarbon selected from the group consisting of naphthalene, methylnaphthalenes, dimethylnaphthalenes, trimethylnaphthalenes, tetramethylnaphthalenes, pentamethylnaphthalenes, hexamethylnaphthalenes, and their mixtures with one or more benzene hydrocarbons selected from the group consisting of benzene, toluene, xylenes, trimethylbenzenes, tetramethylbenzenes, pentamethylbenzene, and hexamethylbenzene to produce a product;
• 2) separating the product obtained in step (1) into fractions comprising (a) a fraction containing benzene aromatic hydrocarbons, naphthalene and methylnaphthalene, (b) a fraction containing dimethylnaphthalenes and (c) a fraction containing polymethylnaphthalenes;
• 3) separating fraction (b) into a fraction containing 2,6-dimethylnaphthalene and a fraction (d) containing 1,5 and/or 1,6-dimethylnaphthalenes, optionally mixed with other isomers of dimethylnaphthalene;
• 4) subjecting fraction (d) to isomerization, under at least partially liquid phase conditions, in the presence of an MTW zeolite, at a temperature ranging from 100 to 400.degree. C.