Synthesis of 1,3-Butadiene and Its 2-Substituted Monomers for Synthetic Rubbers

Abstract

Synthetic rubbers fabricated from 1,3-butadiene (BD) and its substituted monomers have been extensively used in tires, toughened plastics, and many other products owing to the easy polymerization/copolymerization of these monomers and the high stability of the resulting material in manufacturing operations and large-scale productions. The need for synthetic rubbers with increased environmental friendliness or endurance in harsh environments has motivated remarkable progress in the synthesis of BD and its substituted monomers in recent years. We review these developments with an emphasis on the reactive routes, the products, and the synthetic strategies with a scaling potential. We present reagents that are primarily from bio-derivatives, including ethanol, C4 alcohols, unsaturated alcohols, and tetrahydrofuran; the major products of BD and isoprene; and the by-products, activities, and selectivity of the reaction. Different catalyst systems are also compared. Further, substituted monomers with rigid, polar, or sterically repulsive groups, the purpose of which is to enhance thermal, mechanical, and interface properties, are also exhaustively reviewed. The synthetic strategies using BD and its substituted monomers have great potential to satisfy the increasing demand for better-performing synthetic rubbers at the laboratory scale; the laboratory-scale results are promising, but a big gap still exists between current progress and large scalability.

Direct 1,3-butadiene biosynthesis in Escherichia coli via a tailored ferulic acid decarboxylase mutant

“…One of the most valuable industrial raw materials used to produce synthetic rubber (e.g., styrenebutadiene rubber and polybutadiene rubber) and engineering plastic (e.g., acrylonitrile-butadiene-styrene resin) is 1,3-butadiene, a C4 conjugated diene with the simplest structure. 12 The global market size of 1,3butadiene was $19 billion in 2019, and its global annual demand is >12 million MT. Conventionally, almost all of 1,3-butadiene is synthesized from a C4 fraction that is a by-product of naphtha cracking during ethylene production.…”

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

“…With two successive dehydrations, 1,4-butanediol could potentially be converted to 1,3butadiene, thus completing the production of highly valuable and sought after C4 olefins from sugar with relatively little energy input. This potential reaction mechanism was proposed by Qi et al with 3-butene-1-ol as the key intermediate [15]. However, the use of conventional catalysts, both acidic and basic, can lead to problems, particularly the formation of cyclic compounds during dehydration rather than the straight chain butadiene [27,28].…”

“…In several of the aforementioned methods, particularly bioethanol production, the desired One ethanol molecule is dehydrogenated to form acetaldehyde, which then couples with another ethanol to form a four-carbon chain which then undergoes two dehydrations and a hydrogenation to form the final product, 1,3-butadiene [15].…”

“…Historic ethanol-to-BD production routes were proven to work in a somewhat limited fashion with up to 60 percent butadiene yield and 70 percent selectivity achieved by the German company I.G. Farben at atmospheric pressures [15]. These methods largely fell out of favor in industry by the 1960s as massive naphtha cracking operations in ethylene plants began to be able to produce cheaper 1,3-butadiene as a side product.…”

“…Instead, C4+ olefins have historically been produced via the selective dehydrogenation of C4+ alkanes or as a byproduct from other processes such as naphtha cracking. An estimated 95 percent of worldwide production of 1,3butadiene, an important polyunsaturated olefin used in the production of rubber for automobile tires, was produced in one (or both) of these two ways as of 2018 [15]. These processes, which already rely on the use of C4+ feedstocks, leave the price of the important C4 olefins in flux due to inconsistent feedstock supply, and may be unsustainable regardless due to limited natural resources, creating the impetus for a well-established direct synthesis route to these important monomers [1,3,[12][13][14][15].…”