Building blocks light olefins

The attempted synthesis of [njcyclophenacenes has also been reported. Kuwata-ni and coworkers reported the synthesis of a pentabenzo[20]annulene, as a possible precursor to [10]cyclophenacene (Scheme 2.3) [16]. Light-induced electrocycli-zation of the precursor was unsuccessful because of isomerization of the (Z)-olefin into the (E)-olefin, which undergoes an undesirable transannular reaction [17]. St. Martin and Scott tried to synthesize [12]cyclophenacene, but attempts at the macrocyclic oligomerization of substituted naphthalene and phenanthrene building blocks by flash vacuum pyrolysis method were unsuccessful [18]. 

Thus, the building blocks for synthesis of commodity organic chemicals— synthesis gas, the light olefins ethylene, propylene, and butadiene, and BTX— can be obtained from biomass feedstocks by thermochemical conversion. 

After they leave a refinery, most petrochemicals are used as feedstock for petrochemical plants. Among olefins, ethylene and propylene are building blocks for plastics and specialty chemicals. The olefin butadiene is processed to eventually form synthetic rubber. Among aromatics, benzene is used in the production of synthetic dyes, detergents, and such innovative products as polycarbonates that form light hard plastic shells in many electronic items such as mobile phones. Toluene and xylene are used for solvents or as building blocks for other chemicals, creating, for example, polyester fibers. 

C-C coupling is at the core of organic synthesis and serves as the foundation for generating more complex organic compounds from simpler ones [10]. Light olefins such as ethene and propene, are often used as building blocks in the production of chemicals. 

As with the reformer, the properties of the FCC gasoline are affected by the operating conditions, feedstock, catalyst selection, additives and new hardware technology. In addition, the FCC produces light olefins which are the building blocks for the major new clean ftiel processes such as etherification and alkylation. 

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