Phillips olefin disproportionations

Disproportionation of Olefins. Disproportionation or the metathesis reaction offers an opportunity to convert surplus olefins to other desirable olefins. Phillips Petroleum and Institut Fransais du Petrc le have pioneered this technology for the dimerization of light olefins. The original metathesis reaction of Phillips Petroleum was intended to convert propylene to 2-butene and ethylene (58). The reverse reaction that converts 2-butene in the presence of excess ethylene to propylene has also been demonstrated (59). A commercial unit with a capacity of about 136,000 t/yr of propylene from ethylene via 2-butene has been in operation in the Gulf Coast since 1985 (60,61). In this process, ethylene is first dimerized to 2-butene foUowed by metathesis to yield propylene. Since this is a two-stage process, 2-butene can be produced from the first stage, if needed. In the dimerization step, about 95% purity of 2-butene is achieved at 90% ethylene conversion. 

A second route based on olefin disproportionation was developed by Phillips Petroleum (131). Here isobutylene reacts with propylene to form isoamylenes, which are dehydrogenated to isoprene. 2-Butene can be used in place of propylene since it also yields isoamylene and the coproduct propylene can be recycled. Use of mixed butylenes causes the formation of pentenes, giving piperjlene, which contaminates isoprene. 

The first commercial application of olefin disproportionation was in 1966 87) Shawinigan Chemicals Ltd. at the Varennes complex near Montreal, Quebec brought onstream the Phillips Triolefin Process88) for converting propylene into polymerization-grade ethylene and high-purity butenes. Pilot plant development, reported by Johnson 89), showed that during a 20-hour test propylene conversion remained nearly constant at 43 per cent and efficiency of converted propylene to ethylene and n-butenes increased from 93 to 99 per cent. 

Robert Banks Phillips Petroleum Olefin disproportionation... 

Table 8-5 indicates the wide variety of catalysts that can effect this type of disproportionation reaction, and Figure 8-7 is a flow diagram for the Phillips Co. triolefm process for the metathesis of propylene to produce 2-butene and ethylene. Anderson and Brown have discussed in depth this type of reaction and its general utilization. The utility with respect to propylene is to convert excess propylene to olefins of greater economic value. More discussion regarding olefin metathesis is noted in Chapter 9. 

Triolefin Also called Phillips Triolefin. A process for disproportionating propylene into a mixture of ethylene and 2-butene. The reaction takes place at 160°C over a cobalt-molybdenum catalyst on an alumina base. Developed by the Phillips Petroleum Company from 1963. A commercial plant was built by Gulf Oil Canada in 1966 and operated by Shawinigan between 1966 and 1972 before closing for economic reasons. See also Olefin Conversion Technology, Meta-4. 

The results of the above and similar studies provided the basis for a key contribution that aided the development of olefin metathesis technology at Phillips D. L, Crain, in 1963, recognized that product distributions obtained by disproportionation of various olefins and mixtures of olefins could be explained by a concerted "four-center" mechanistic scheme (Figure 5A). This mechanism was proposed in a later publication of Bradshaw and coworkers of British Petroleum (11), Although the simple "four-center", or "quasi-cyclobutene," scheme is no longer the... 

Olefins Conversion Technology [OCT] A process for converting mixtures of ethylene and butenes to propylene by metathesis (disproportionation). Based on technology developed by Phillips Petroleum in the... 

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