Published June 1981
A propylene oxide process has been developed wherein the propylene is epoxidized through the use of an organic hydroperoxide as the oxidizing agent. During the reaction the hydroperoxide is itself converted to an alcohol. In the present study, ethylbenzene hydroperoxide, made by oxidation of ethylbenzene, is used in an analogous operation for the epoxidation of mixed n-butylenes to butylene oxides. At the same time, ethylbenzene hydroperoxide forms the corresponding alcohol, methylphenylcarbinol, which on dehydration becomes styrene, a coproduct of the process. The mixed 1-butene and 2-butene oxides are reduced with hydrogen to n- and sec-butanols. The n-butanol is recovered as a plant product. The sec-butanol is dehydrogenated to methyl ethyl ketone, which constitutes the other principal plant product.
For the present evaluation, we have designed a unit to produce 172 million lb/yr (78,000 metric tons/yr) of n-butanol plus MEK. The feedstock is the C4 raffinate from an MTBE unit. The C4 raffinate amounts to 175 million lb/yr; the ethylbenzene requirement is 336 million lb/yr. Plant production rates are 300 million lb/yr of styrene, 90 million lb/yr of n-butanol and 82 million lb/yr of MEK.
The process has the disadvantage of requiring the marketing of several chemical products in fixed proportions. On the other hand, the economics appear moderately attractive, and would improve in locations where mixed n-butylenes are valued only as fuel, rather than as alkylation plant feed as was assumed in this study.