liquid-phase oxidation of cyclohexane to adipic acid in a single stage

Abstract

Systematic studies on the liquid-phase catalytic oxidation of cyclohexane to adipic acid by oxygen in a single stage using acetic acid as the solvent and cobalt acetate as the catalyst were carried out in the temperature range 90-140 °C under a pressure of 5 atm in a semicontinuous stirred reactor. Cyclohexanone to an extent of 1 % was used as the initiator. The reaction was found to be first-order with respect to cyclohexane. The effects of the various operating parameters, viz., temperature, catalyst concentration, solvent concentration, stirrer speed, and pressure of oxidation, on the overall reaction rate constant were assessed. The influence of mass transfer on the overall rate was deciphered. The mass-transfer coefficients were computed on the basis of penetration theory by employing the linearization approximation technique. The results were compared with those predicted by simple expressions in the literature.The liquid-phase oxidation of cyclohexane is an industrially important process for making cyclohexanol, cyclohexanone, and adipic acid. Adipic acid is extensively used

Liquid-phase oxidation of cyclohexanone to dibasic acids with immobilized cobalt catalyst

“…The reaction was carried out in a homogeneous liquid-phase system in the presence of a solvent (acetic acid appeared to be most useful) using salts of transition metals (such as Co, Mn, Cr, etc.) as the catalysts (Reis, 1965(Reis, ,1971; Onopchenko and Schulz, 1973; Tanaka, 1974; Danly and Campbell, 1978;Rao and Raghunathan, 1986). Dibasic acids (including adipic acid, glutaric acid, and succinic acid) are the major products, and this makes the mechanism of the oxidation of cyclohexane different from the classical autoxidation of cyclohexane.…”

Emerging catalytic processes for the production of adipic acid

“…Sporadic reports over the past decades have proposed the direct oxidation of cyclohexane to AA using Co and Mn catalysts with acetic acid as the solvent. [61][62][63][64][65] Inspired by this work, Bonnet et al investigated the combination of lipophilic carboxylic acids and low loadings of Co and Mn salts. 66 The choice for lipophilic carboxylic acids was motivated by the need to facilitate their recycling after partitioning of AA in the aqueous phase ( Fig.…”

Adipic Acid

“…Reaction temperature is a moderate 70-1008C. References to air oxidation processes have continued to appear through the 1990s (131)(132)(133)(134)(135)(136).…”