Method for producing zeolites with reduced surface acidity
First Claim
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1. A process for the selective surface dealumination of an organic-containing zeolite comprising contacting said zeolite with dicarboxylic acid for a sufficient time to effect at least about a 25% reduction in surface acidity with less than about 50% overall dealumination.
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Abstract
A process for the selective surface dealumination of organic-containing zeolites by contacting the zeolite with dicarboxylic acid, such as oxalic acid. The treatment results in a reduction in surface acidity without a significant reduction in overall activity. The organic may be a directing agent used in the zeolite synthesis or introduced into the pores of the zeolite after thermal treatment.
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28 Claims
- 1. A process for the selective surface dealumination of an organic-containing zeolite comprising contacting said zeolite with dicarboxylic acid for a sufficient time to effect at least about a 25% reduction in surface acidity with less than about 50% overall dealumination.
- 23. A process for the selective surface dealumination of a zeolite containing at least about 5 wt % of an organic material comprising contacting the zeolite with oxalic acid for a sufficient time to effect at least about a 25% reduction in surface acidity with less than about 50% overall dealumination.
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26. A process for the selective surface dealumination of an organic-containing zeolite comprising contacting said zeolite with dicarboxylic acid for a time in the range of about 10 minutes to about 1 hour to effect at least about a 25% reduction in surface acidity with less than about 50% overall dealumination.
- 27. A process for the selective surface dealumination of an organic-containing zeolite Beta comprising contacting said zeolite Beta with dicarboxylic acid for a sufficient time to effect at least about a 25% reduction in surface acidity with less than about 50% overall dealumination.
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