Chemistry of hydrocarbon compounds – Purification – separation – or recovery – By addition of extraneous agent – e.g. – solvent – etc.
Reexamination Certificate
1997-07-03
2001-05-15
Griffin, Walter D. (Department: 1764)
Chemistry of hydrocarbon compounds
Purification, separation, or recovery
By addition of extraneous agent, e.g., solvent, etc.
C585S801000, C585S002000, C585S003000, C210S909000, C210S702000, C210S710000, C210S711000
Reexamination Certificate
active
06232518
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to methods for separating benzene from mixtures of other hydrocarbons, and recovering a high concentration of benzene from such mixtures. In particular, the invention relates to a method for removing and recovering a high concentration of benzene from gasoline or reformate using cyclodextrins as complexing agents.
BACKGROUND OF THE INVENTION
Benzene is a highly carcinogenic compound which either is found in or produced during the processing of many hydrocarbon streams. One hydrocarbon substrate or stream in which benzene is found is motor gasoline. In an attempt to reduce pollution from automobile exhaust, environmental regulations have been passed in the United States and in other countries setting limits on the amount of benzene that can exist in motor gasoline in order for the sale of that gasoline to be legal. These regulations can be met only if benzene is removed either from the motor gasoline, itself, or from reformate, which is a major source of the benzene found in motor gasoline.
A typical reformate contains in the range of from about 2-4 wt % benzene in a mixture of paraffins, olefins, naphthenes, toluene, xylenes, ethylbenzene (EB), 9-carbon aromatics (A9s), 10-carbon aromatics (A10s), and other heavy hydrocarbons. Currently, no economically satisfactory technology is capable of directly removing benzene from such a mixture. Existing processes require the use of an expensive benzene heart-cut distillation column, which makes a C6-C7+split of the reformate, producing an overhead stream of 20-30% benzene and 70-80% non-aromatics. The heart-cut benzene stream then must be treated using other known methods, such as adsorption, extraction, etc., to produce high purity benzene or other benzene products.
An economically efficient method is needed for directly removing benzene from hydrocarbon substrates, such as reformate and/or motor gasoline.
SUMMARY OF THE INVENTION
The present invention provides a method of separating benzene from a hydrocarbon mixture comprising providing a mixture comprising benzene and at least one other hydrocarbon, treating said mixture with a complexing agent comprising at least one cyclodextrin in an amount and under conditions effective to form complexes comprising said cyclodextrin and at least a portion of said benzene, and separating said complexes from said mixture.
REFERENCES:
patent: 3456028 (1969-07-01), Gerhold et al.
patent: 3465055 (1969-09-01), Gleim et al.
patent: 3472835 (1969-10-01), Buckler et al.
patent: 4426292 (1984-01-01), Wernick et al.
patent: 5095173 (1992-03-01), Uemasu et al.
patent: 5177302 (1993-01-01), Uemasu et al.
patent: 5200517 (1993-04-01), Uemasu et al.
patent: 4238430 (1994-05-01), None
patent: 42 38 430 A1 (1994-05-01), None
patent: 0487818A1 (1992-06-01), None
Chemical Abstracts, vol. 84, No. 19, May 10, 1976, Columbus, Ohio, US; abstract No. 135074g, p. 449; XP002077719.
PCT US98/13403 International Search Report.
Exxon Mobil Chemical Patents Inc.
Griffin Walter D.
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