| 摘要 |
2139785 9400409 PCTABS00030 Novel nonextractive processes for producing high purity and chemical grade aromatics (e.g., benzene, toluene, xylene) from hydrocarbon streams are described. For aromatic feedstocks containing close-boiling nonaromatic components, the stream is contacted with an acidic catalyst. As a result, nonaromatic impurities having boiling points in the aromatic range are catalytically converted to other species having boiling points substantially outside the aromatic boiling range. The desired aromatics in the product may be separated by simple distillation. Nonextractive processes incorporating a dual catalyst treatment are also described. Naphtha feeds are aromatized in a first stage by contact with a nonacidic catalyst, producing a mixture of aromatics and nonaromatic impurities with boiling points in the aromatic range. In a second stage, the mixture is contacted with an acidic catalyst under conditions that produce an effluent substantially free of nonaromatic impurities having boiling points in the aromatic range. High purity aromatics may be obtained by performing a simple distillation of the product.
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