Muconic acid, catalytic hydrogenation

McBride and Hall (37,38) reported the first observation of a controlled catalytic reaction on alumina using IETS. They studied the catalytically induced transfer hydrogenation from water vapor to unsaturated hydrocarbon chains chemisorbed on alumina at both ends of the chain. They absorbed muconic acid ( trans-trans-1,3 butadiene 1,4 dicarboxylic acid, HOOC-CH=CH-CH=CH-COOH ) onto oxidized aluminum strips using the liquid doping technique. The samples were returned to the vacuum system, and in the presence of 0.3 torr of D2O vapor, heated to up to 400° C by passing current through a heater strip evaporated on the back of the glass slide. The films were then allowed to cool and the junctions completed by evaporation of the Pb counter electrode. 

Another synthesis of adipic acid involves the microbial degradation of toluene to muconic acid (hexa-2,4-dienedioic acid), which undergoes catalytic hydrogenation to give adipic acid. If this process can be made economically competitive, it might produce less environmental impact than the chemical synthesis from benzene. 

Adipic acid (1,4-butanedicarboxylic acid/hexanedioic acid) is tiie most essential aliphatic dicarboxylic acid and is white crystalline powder in nature. Adipic acid is largely used for the production of nylon 6,6. The synthesis of adipic acid is as follows biosynthesis of cisfiis-muconic acid by the fermentation of glucose, followed by catalytic hydrogenation to adipic acid. In addition to tiie optimization of culture conditions for its production, the separation of adipic acid from an aqueous medium at high purity levels is necessary for polymer-grade products. The catalytic conversion of muconic acid to adipic acid requires to be furtiier explored. 

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