Selective surface dealumination of zeolites using dicarboxylic acid
AssigneeMobil Oil Corporation
InventorsMinas R. Apelian, Anthony S. Fung
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Abstract
A process for the selective surface dealumination of a zeolite having a Constraint Index greater than 1 by contacting the zeolite with dicarboxylic acid, such as oxalic acid.
Claims22
A process for the selective surface dealumination of a zeolite having a Constraint Index greater than 1 comprising contacting the zeolite with dicarboxylic acid for a sufficient time to effect at least about a 40% reduction in surface acidity with less than about 50% overall dealumination.
A process for the selective surface dealumination of a zeolite having a Constraint Index greater than 1 comprising contacting the zeolite with oxalic acid for a sufficient time to effect at least about a 40% reduction in surface acidity with less than about 50% overall dealumination.
A process for the selective surface dealumination of a zeolite having a Constraint Index greater than 1 comprising contacting the zeolite with dicarboxylic acid for a time in the range of about 10 minutes to about 1 hour to effect at least about a 40% reduction in surface acidity with less than about 50% overall dealumination.
A process for the selective surface dealumination of a zeolite having the structure of ZSM-23 comprising contacting the zeolite with dicarboxylic acid for a sufficient time to effect at least about a 40% reduction in surface acidity with less than about 50% overall dealumination.
A process for the selective surface dealumination of a zeolite having the structure of ZSM-5 comprising contacting the zeolite with dicarboxylic acid for a sufficient time to effect at least about a 40% reduction in surface acidity with less than about 50% overall dealumination.
Dependencies are inferred from the claim text.