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AssigneeEnichem S.p.A.
InventorsGiannino Pazzuconi, Carlo Perego, Giuseppe Bellussi
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A highly selective process is described for preparing 2,6-dimethylnaphthalene which comprises reacting a naphthalene hydrocarbon selected from naphthalene, methylnaphthalenes, dimethylnaphthalenes, trimethylnaphthalenes, polymethylnaphthalenes, and/or their mixtures with one or more benzene hydrocarbons selected from benzene, toluene, xylenes, trimethylbenzenes, tetramethylbenzenes, pentamethylbenzene and/or hexamethylbenzene, under at least partially liquid phase conditions and in the presence of a catalytic composition comprising a zeolite belonging to the MTW structural type and at least one element selected from P, B and Si. The process is preferably carried out in the presence of a methylating agent.
1) A process for preparing 2,6-dimethylnaphthalene which comprises reacting a naphthalene hydrocarbon selected from naphthalene, methylnaphthalenes, dimethylnaphthalenes, trimethylnaphthalenes, tetramethylnaphthalenes, pentamethylnaphthalenes, hexamethylnaphthalenes and/or their mixtures with one or more benzene hydrocarbons selected from benzene, toluene, xylenes, trimethylbenzenes, tetramethylbenzenes, pentamethylbenzene and/or hexamethylbenzene, under at least partially liquid phase conditions and in the presence of a catalytic composition comprising a zeolite belonging to the MTW structural type and at least one element A selected from P, Si and B, optionally in the presence of a methylating agent.
11) The process according to any of the claims from 1 to 10, wherein the cationic sites of the zeolite are occupied by at least 50% of hydrogen ions.
33) A process for preparing 2,6-dimethylnaphthalene which comprises:
34) A process for preparing 2,6-dimethylnaphthalene which comprises:
35) A process for preparing 2,6-dimethylnaphthalene which comprises:
38) A process for preparing 2,6-dimethylnaphthalene which comprises subjecting to isomerization 1,6 and/or 1,5-dimethylnaphthalenes, optionally mixed with other isomers of dimethylnaphthalene, by treating said compounds at a temperature ranging from 100 to 400° C., under at least partially liquid phase conditions, in the presence of a catalytic composition containing an MTW zeolite and one or more elements selected from P, Si and B.
40) A method for regenerating the exhausted catalyst deriving from the preparation process of 2,6-dimethylnaphthalene by the reaction, under at least partially liquid phase conditions and in the presence of a catalytic composition comprising a zeolite belonging to the MTW structural type and at least one element A selected from P, B and Si, optionally in the presence of a methylating agent, a naphthalene hydrocarbon selected from naphthalene, methylnaphthalene, dimethylnaphthalene, trimethylnaphthalene, tetramethylnaphthalene, pentamethylnaphthalene, hexamethylnaphthalene and/or their mixtures with one or more benzene hydrocarbons selected from benzene, toluene, xylenes, trimethylbenzenes, tetramethylbenzenes, pentamethylbenzene and/or hexamethylbenzene, said regeneration method comprising treating the exhausted catalytic composition with one or more of said benzene hydrocarbons, in at least partially liquid phase, at a temperature ranging from 200 to 450° C., said temperature being at least equal to that used during the preparation process of 2,6-dimethylnaphthalene.
42) The process according to one or more of the previous claims, wherein the naphthalene hydrocarbon or hydrocarbons are contained in a naphthalene cut obtained by the fractionation of petrochemical streams such as FOK, LCO and heavy fractions from catalytic reforming.
43) The process according to any of the previous claims, wherein the naphthalene hydrocarbon or hydrocarbons are contained in a naphthalene cut obtained by the fractionation of suitable petrochemical streams and subsequent treatment of the cut thus obtained with a solid acid.
48) The process according to any of the claims from 43 to 47, wherein the cut to be subjected to treatment is obtained by the fractionation of FOK, LCO, or the heavy fraction from catalytic reforming.
49) A catalytic composition comprising a zeolite belonging to the MTW structural type and at least one element A selected from P, Si and B.
Dependencies are inferred from the claim text.