Zeolite composition for use in olefinic separations
AssigneeExxon Research & Engineering Co.
InventorsEdward Kantner, David W. Savage, Richard J. Bellows
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Abstract
Basically, the present invention is predicated on the discovery that zeolites that have a high silica to alumina ratio, e.g., a ratio of 20 and above, pore diameters of greater than about 5.0.ANG., and which have substantially no active acid sites, i.e., zeolites which are non-reactive toward olefin isomerization and oligomerization, are especially useful in substantially separating linear olefins and paraffins from hydrocarbon mixtures containing at least linear and branched aliphatic hydrocarbons and optionally containing aromatic and other hydrocarbons.
Claims11
A process for substantial separation of linear olefins and paraffins from mixtures containing at least linear and branched aliphatic hydrocarbons comprising:
- contacting the mixture with a zeolite molecular sieve having a silica to alumina ratio of greater than about 50:1, internal pore diameters of at least 5.0.ANG., and which has been first treated with an acid in an amount sufficient to dissolve at least some of the acid soluble impurities in the zeolite and then treated with sufficient base to neutralize the acidic impurities whereby the sieve is substantially non-reactive toward olefin isomerization and oligomerization, the contacting being conducted under conditions sufficient to effect adsorption of linear olefins and linear paraffins by the zeolite to the substantial exclusion of branched aliphatic hydrocarbons whereby the linear olefins and paraffins are substantially separated from the mixture of aliphatic hydrocarbons.
A method for rendering a high silica to alumina zeolite sieve substantially non-reactive toward olefin isomerization at temperatures ranging from about 10.degree. C. to about 150.degree. C., comprising:
- washing a zeolite sieve having a silica to alumina ratio of greater than about 50:1 with an acid in an amount sufficient to dissolve at least some of the acid soluble impurities in the zeolite and then treating the acid washed zeolite with sufficient base to remove the acid impurities.
A zeolite composition having reduced acid sites prepared by:
- washing a zeolite sieve having a silica to alumina ratio of greater than about 50:1 with an acid in an amount sufficient to dissolve at least some of the acid soluble impurities in the zeolite and then treating the acid washed zeolite with sufficient base to remove the acid impurities.
Dependencies are inferred from the claim text.