Published October 1971
The subject of butylenes (including butene-l, butenes-2, and isobutylene) is of current interest mainly for one of two reasons: (1) The prospective removal or reduction of lead in gasoline will create increased demands for butylenes in the United States. (2) The higher growth rate in demand for ethylene than for its by-products in Japan and Europe has created surpluses of butylenes that often result in these olefins being left in LFG fuels rather than being used in more profitable chemicals. Hence, more than usual emphasis is given to the industry status in this report, including technical factors affecting supply.
Generally, the processing of butylenes is relatively simple in that the largest scale uses do not require separation and purification of these olefins. For several uses, however, pure C4 olefin isomers or mixtures of isomers are required, and the principal ways of producing them are covered here, except for dimerization of ethylene and by production of isobutylene in propylene oxide manufacture, which are covered in other PEP reports. However, the by-product of propylene oxide is made by dehydration of t-butanol, which is also part of the BASF process covered in this report.
There is extensive literature on double bond isomerization of n-butylenes, No significant current demand for such a process is apparent, however, and the subject is not covered herein.
