Review of Established and Emergent Methods for the Production of C4 Olefins

Abstract

Review of Established and Emergent Methods for the Production of C4 Olefins James Koval Current production of C4 olefins is dominated by naphtha cracking and butane dehydrogenation, but significant research interest is developing in alternate feedstocks due to an abundance of inexpensive natural gas and bioethanol. The current C4 olefin production methods are costly, make use of already-depleted petroleum resources, and are often hazardous to workers, which forms the impetus for investigation into alternative methods and assessment of their viability as a future means of olefin production. Methods of natural gas conversion to higher order hydrocarbons are discussed, including Fischer-Tropsch synthesis and oxidative methane coupling, each of which could form the first step in a hypothetical natural gas-to-olefins process. The historically common Lebedev, Ostromislensky, and Fripiat methods for 1,3-butadiene production from ethanol feedstocks are described and analyzed, although these processes largely fell out of favor in the decades following World War II in favor of sources derived from naphtha cracking. Another well-known process involving C4 olefins, olefin metathesis, is considered, although the reaction is more commonly used to produce propylene. Biological processes are discussed as well, including the well-known production of bioethanol from sugars and starches, and also more novel processes such as an effort to use genetically engineered microorganisms to produce specific intermediates for olefin production, and in some cases, direct olefin production from these organisms. Finally, several promising schemes are identified and analyzed, in an attempt to compare their potential viability in key areas. Two of the most promising emergent methods today identified in this review are the bio-catalyzed production of 1,4-butanediol and/or butadiene using E. coli, and a microwave radiation-assisted scheme in which methane is selectively dimerized twice to form 1-butene.