Cosden Technology, Inc.

Kevin P Menard

James R Butler

James M Watson

Debra L Kendall

J Randall Curtis

Eugene W Cotten, Jr

A process for the alkylation of aromatic compounds employing silicalite of extremely low sodium content. A feedstock containing an aromatic substrate such as benzene is supplied along with an alkylating agent such as ethylene to a reaction zone containing a silicalite alkylation catalyst having a sodium content of less than 100 ppm Na.sub.2 O. Steam may be cofed to the reaction zone in an amount of at least 1 wt. % based upon the aromatic substrate. The low sodium silicalite has a substantially better aging quality in the alkylation process than does silicalite which normally has a higher sodium content.

Aromatic alkylation process

A process for the disproportionation of a toluene feedstock containing ethylbenzene over an aluminum deficient mordenite catalyst. The mordenite catalyst has a silica/alumina mole ratio of at least 30. The feedstock contains at least 5 wt. % ethylbenzene. Hydrogen is supplied to the disproportionation reactor zone along with the toluene feedstock.

Toluene disproportionation process

A process for the disproportionation of a toluene containing feedstock over an aluminum deficient mordenite catalyst having a silica/alumina mole ratio of at least 30. The feedstock and hydrogen co-feed are supplied to a reaction zone containing the mordenite catalyst and which is operated under a temperature and pressure condition to effect the disproportionation of toluene to benzene and xylene. The supply of toluene feedstock to the reaction zone is interrupted while continuing the supply of hydrogen to the reaction zone. By continuing the supply of hydrogen to the reaction zone during periods of interruption of the toluene feedstock, the aging quality of the aluminum-deficient mordenite catalyst is improved.

Process for the isomerization of a xylene feedstock employing a silicalite catalyst. A xylene feedstock containing a mixture of xylene isomers and ethylbenzene is passed to a reaction zone containing the silicalite catalyst. Para-xylene is present in the feedstock in less than an equilibrium amount, and ethylbenzene is present in a concentration greater than the para-xylene concentration. Hydrogen and/or water are also supplied to the reaction zone. The reaction zone is operated under conditions to effect isomerization of xylene isomers to provide an increased para-xylene content, and disproportionation of ethylbenzene to provide a decreased ethylbenzene content.

Xylene isomerization process

Process for the isomerization of xylene feedstock employing an aluminum-deficient mordenite catalyst. The xylene feedstock is passed into a reaction zone and in contact with a mordenite catalyst having a silica/alumina mole ratio of at least 30. The xylene feedstock may comprise a substantially pure meta-xylene, a mixture of xylene isomers, or in the preferred embodiment, a mixture of xylene isomers and ethylbenzene in which para-xylene is present in less than an equilibrium amount, and ethylbenzene present in an amount greater than the para-xylene content. The reaction zone is operated at a temperature within the range of 350.degree.-600.degree. C. and a hydrogen pressure within the range of 200-1000 psig to effect isomerization of xylene isomers to provide an increased para-xylene content and disproportionation of ethylbenzene to provide a reduced ethylbenzene content in the product.

Process for the disproportionation of toluene employing an aluminum deficient mordenite catalyst. A toluene containing feedstock is supplied to a reaction zone containing a mordenite catalyst having a silica/alumina mole ratio of at least 30. The toluene WHSV is more than one. A hydrogen cofeed is supplied at a hydrogen/toluene mole ratio of 3-6, and the reaction zone is operated at a temperature within the range of 370.degree.-500.degree. C. and a hydrogen pressure of at least 500 psig. The toluene feedstock can have a moisture content in excess of 25 ppm and typically will have a water content ranging from about 50 ppm up to about the saturation point, about 250 ppm. A start-up procedure employs passing a hot preflush gas over the catalyst to dehydrate water from the catalyst prior to passing the toluene feedstock to the catalyst.

A process for the distillation of readily polymerizable vinyl aromatic compounds which comprises subjecting said compounds to distillation conditions in the presence of an effective amount of a pretreated polymerization inhibitor selected from the group consisting of asphalts, asphaltenes and any combination thereof. The inhibitor is pretreated by subjecting the inhibitor to a process for substantially increasing the free radical content therein.

Polymerization inhibitor for vinyl aromatic compounds

A process for the distillation of readily polymerizable vinyl aromatic compounds which comprises subjecting said compounds to distillation conditions in the presence of oxygen and an effective amount of asphaltene as a polymerization inhibitor.

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Big Spring, TX, United States of America

Kevin P Menard