Propylene oxide coproduct with MTBE

Hydroperoxide Process. The hydroperoxide process to propylene oxide involves the basic steps of oxidation of an organic to its hydroperoxide, epoxidation of propylene with the hydroperoxide, purification of the propylene oxide, and conversion of the coproduct alcohol to a useful product for sale. Incorporated into the process are various purification, concentration, and recycle methods to maximize product yields and minimize operating expenses. Commercially, two processes are used. The coproducts are / fZ-butanol, which is converted to methyl tert-huty ether [1634-04-4] (MTBE), and 1-phenyl ethanol, converted to styrene [100-42-5]. The coproducts are produced in a weight ratio of 3—4 1 / fZ-butanol/propylene oxide and 2.4 1 styrene/propylene oxide, respectively. These processes use isobutane (see Hydrocarbons) and ethylbenzene (qv), respectively, to produce the hydroperoxide. Other processes have been proposed based on cyclohexane where aniline is the final coproduct, or on cumene (qv) where a-methyl styrene is the final coproduct. 

The / f/-butanol (TBA) coproduct is purified for further use as a gasoline additive. Upon reaction with methanol, methyl tert-huty ether (MTBE) is produced. Alternatively the TBA is dehydrated to isobutylene which is further hydrogenated to isobutane for recycle ia the propylene oxide process. 

Standard Oil of California added the petrochemicals of Gulf Oil, purchased in 1984, to its subsidiary Chevron Chemical. Other United States petrochemical producers took advantage of special circumstances. Amoco was served by a strong terephthalic (TPA) base and its good performance in polypropylene Arco, by its Lyondell subsidiary in Channelview, Texas, and by its development of the Oxirane process through which propylene oxide could be produced by direct oxidation with styrene as a coproduct. The process also led to MTBE (methyl tertiary-butyl ether), the antiknock agent used as a substitute for tetraethyl lead. 

PO has historically been produced by the chlorohydiin method or the organic peroxide method. While these processes generate large amounts of by-products (namely, calcium chloride) they also deliver coproducts such as teft-butanol, which may be used for the production of methyl tertiary-butyl ether (MTBE), or styrene. Key producers of PO are Sumitomo, Repsol, and Huntsman (275). Shell s SMPO (Propylene Oxide with... 

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