Annex 1 Alkane Feedstocks. Alternative Routes to Acetic Acid and Acrylonitrile

Annex 1 Alkane Feedstocks. Alternative Routes to Acetic Acid and Acrylonitrile 

The direct synthesis of chemicals from alkanes is an attractive alternative to that via olefins. Alkanes are abundant and cheaper, while the elimination of the dehydrogenation unit allows simplified process designs and energy savings. Oxidations of several alkanes are of industrial interest and are being investigated (Table 3) at the most advanced stage are those of ethane to acetic acid and of propane to acrylonitrile. 

The appeal of an acetic acid process, based on ethane oxidation, lies mostly in the absence of the need for the energy demanding step for syngas production. On the other hand, it has to compete not only with the well established methanol carbonylation (Section 4.2), but also with the current utilization of ethane in steam crackers for ethylene manufacture. In fact, ethane feedstock becomes attractive for acetic acid production if it is locally abundant and can be supplied at minimal cost, e.g., in a petrochemical complex close to a large gas field. The construction of a semi-commercial plant of 30 kt/a in the Persian Gulf region has been announced. 

The oxidation of ethane to acetic acid is believed to proceed via the intermediate formation of ethylene (Equation Al). The catalysts are multicomponent mixed oxides, having optimized compositions for ethane oxydehydro-genation (Mo-V oxides) and ethylene oxidation (Pd, Nb oxide). Reported 

Propane Acrylonitrile Acrolein, Acrylic acid Pilot plant 

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