Chemistry of hydrocarbon compounds – Purification – separation – or recovery – By plural serial diverse separations
Patent
1980-02-12
1981-05-05
O'Keefe, Veronica
Chemistry of hydrocarbon compounds
Purification, separation, or recovery
By plural serial diverse separations
585834, 585843, 585845, 585847, 585837, 585852, C07C 7177
Patent
active
042660866
ABSTRACT:
Conjugated diolefins contaminated with relatively high levels of acetylenic impurities in a hydrocarbon feedstream are purified by a cyclic, liquid phase, predominantly catalytic cracking process which selectively removes alpha-acetylenes in a single pass. The energy requirement for removing the alpha-acetylenes in this liquid phase process are from about one-third to about one-fifth as great as that required in a comparable vapor phase process. A feedstream containing about equal weights of butadiene and mixed monoolefins and alkanes contaminated with alpha-acetylenes including vinyl acetylene and methyl acetylene, inter alia, in an amount up to about 1.0 percent by weight (% by wt) of the feedstream, is contacted in the liquid phase with a supported Group I B metal oxide catalyst in the absence of hydrogen, at a temperature in the range from about 200.degree. F. to about 260.degree. F. Despite the relatively high temperature range at which butadiene monomer is contacted with the catalyst for a relatively long time, the loss of diolefin due to polymerization is less than 1% by wt, due to the use of an inhibitor which inhibits polymerization but does not affect the performance of the catalyst. Vinyl acetylene content of the effluent is generally less than bout 50 ppm in the single pass process which is carried out in a fixed bed reactor operating at elevated pressure. In an analogous process, from a crude isoprene feedstream containing up to about 1.0% by wt of isopropenyl acetylene and methyl acetylene, inter alia, an isoprene effluent is recovered having less than about 50 ppm alpha-acetylenes. The isoprene effluent, substantially free from poisons for a polyisoprene polymerization catalyst, contains essentially all the cyclopentadiene present in the feedstream. Cracking of impurities in the liquid phase minimizes the loss of this known cracking catalyst, permits it to have a much longer life, and, like the vapor phase catalytic cracking process using the same catalyst, produces at least 90% conversion of the acetylenes.
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Lobo Alfred D.
O'Keefe Veronica
Powell, Jr. J. Hughes
The B. F. Goodrich Company
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