Acetylene, conversion from toluene

Ethylene from cracking of the alkane gas mixtures or the naphtha fraction can be directly polymerized or converted into useful monomers. (Alternatively, the ethane fraction in natural gas can also be converted to ethylene for that purpose). These include ethylene oxide (which in turn can be used to make ethylene glycol), vinyl acetate, and vinyl chloride. The same is true of the propylene fi action, which can be converted into vinyl chloride and to ethyl benzene (used to make styrene). The catalytic reformate has a high aromatic fi action, usually referred to as BTX because it is rich in benzene, toluene, and xylene, that provides key raw materials for the synthesis of aromatic polymers. These include p-xylene for polyesters, o-xylene for phthalic anhydride, and benzene for the manufacture of styrene and polystyrene. When coal is used as the feedstock, it can be converted into water gas (carbon monoxide and hydrogen), which can in turn be used as a raw material in monomer synthesis. Alternatively, acetylene derived from the coal via the carbide route can also be used to synthesize the monomers. Commonly used feedstock and a simplified diagram of the possible conversion routes to the common plastics are shown in Figure 2.1. 

Desulfurization of petroleum feedstock (FBR), catalytic cracking (MBR or FI BR), hydrodewaxing (FBR), steam reforming of methane or naphtha (FBR), water-gas shift (CO conversion) reaction (FBR-A), ammonia synthesis (FBR-A), methanol from synthesis gas (FBR), oxidation of sulfur dioxide (FBR-A), isomerization of xylenes (FBR-A), catalytic reforming of naphtha (FBR-A), reduction of nitrobenzene to aniline (FBR), butadiene from n-butanes (FBR-A), ethylbenzene by alkylation of benzene (FBR), dehydrogenation of ethylbenzene to styrene (FBR), methyl ethyl ketone from sec-butyl alcohol (by dehydrogenation) (FBR), formaldehyde from methanol (FBR), disproportionation of toluene (FBR-A), dehydration of ethanol (FBR-A), dimethylaniline from aniline and methanol (FBR), vinyl chloride from acetone (FBR), vinyl acetate from acetylene and acetic acid (FBR), phosgene from carbon monoxide (FBR), dichloroethane by oxichlorination of ethylene (FBR), oxidation of ethylene to ethylene oxide (FBR), oxidation of benzene to maleic anhydride (FBR), oxidation of toluene to benzaldehyde (FBR), phthalic anhydride from o-xylene (FBR), furane from butadiene (FBR), acrylonitrile by ammoxidation of propylene (FI BR)... 

Since the meso-ionic reactants (1) are readily accessible from (6) (and ultimately from mercaptoarylacetic acids), their conversion into isothiazoles (8) has been successfully developed as a synthetic route. They are treated with acetylene-mono- or -di-carboxylic acid esters in toluene at 60—100 °C, and afford, with loss of carbon dioxide, good yields of isothiazoles (8), probably by way of labile intermediates of type (7). 

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