Aerobic coupling of aqueous phenol catalyzed by cuprous chloride: basis of a novel dephenolization scheme for phenolic wastewaters

Abstract

Ind. Eng. Chem. Process Des. Dev. 1983, 22, 477-482 y = dimensionless amount adsorbed (= q/qo), dimensionless 2 dimensionless axial position in the column (= kpG/u), z = axial position in the column, m or cm ZE = column length, m or cm Greek Letters Subscripts in = value at the column inlet out = value at the column outlet dimensionless = value at equilibrium Registry No. CH,Br, 74-83-9; C, 7440-44-0. 477 t = void fraction of the bed, dimensionless { = dimensionless parameter (= kfR/5De), dimensionless 0 = dimensionless time (= kp,(t -('/u)z)/pb(qo/co)), di-I.L = viscosity of the gas, g/cm s [ = dimensionless radial position (= r / R ) , dimensionless pb = bulk density of the bed, g/cm3 pf = density of the gas, g/cm3 ps = particle density, g/cm3 r = dimensionless parameter (= kp,(u/ V)/Pb(qo/Co)), di-mensionless m e n s i o n 1 e s s Literature Cited Carberry, J. J. AIChE J . 1960, 6 , 460. Chang, F. H. I.; Tan, K. S.; Spinner, I. H. AZChE J . 1973, 79, 188, Chu, J. C.; Kaiii, J.; Wetteroth, W. A. Chem. Eng. Rog. 1953, 49, 141. Cooney, D. 0.; Shieh, D. AIChE J. 1972, 78, 245. Hashimoto, K.; Miwa, K.; Negate, S. J. W m . Eng. Jpn. 1975, 8 , 367. Mor, L.; Mor, L. A.; Sldeman, S.; Brandes, J. Chem. Eng. Sci. 1980, 35, 725.The discovery that cuprous chloride can effect specifically the aerobic coupling of aqueous phenol under mild reaction conditions ( T < 60 O C , Po? < 1 atm) has led us to propose a novel dephenoiization scheme for high strength phenolic wastewaters. As envisioned In the proposed scheme, aqueous phenols will be converted aerobically and catalytically into insoluble coupling products which may then be easily separated from the wastewaters. The recovered soli organics may be disposed of as a fuel. The low costs of cuprous chloride and oxygen, the simplicity of the scheme, and the fuel value of the recovered organics make the scheme highly promising. Kinetic studies with ammoniacal phenol solutions indicate that the coupling reaction is first order with respect to cuprous chloride catalyst, half order with respect to oxygen, approximately 1.7th order with respect to phenol, and second order with respect to base. At 26 O C and pH 9.7, the rate constant is such that the half-life of a 0.05 M aqueous phenol solution in the presence of 1.58 g/L of capper catalyst and 1 atm oxygen pressure is about 2 h. The reaction activation energy is 12.5 kcal/g-mol. Humic acids are believed to the the major components of the coupling products. A preliminary study with actual coal gasification wastewater confirms the promising nature of the proposed coupling-dephenolization scheme.Fault detection and diagnosis are Wustrated by application of on-line parameter estimation techniques to a nonlinear chemical reactor. An extended Kalman filtering algorithm was successfully used to estimate both the states and time varylng parameters corresponding to faults in a lumped parameter system. Trajectories of parameter estimates were compared with predetermined confidence limits established under normal operating conditions. The ...

Oxidative coupling and the irreversible adsorption of phenol by graphite

“…1 [8,11], including dihydroxybiphenyls and phenoxyphenols, in good agreement with proposed theory [12]. Such products have been identified in organic solvent extracts of phenol-loaded carbons [6,[8][9][10]16].…”

Oxidative coupling of phenols on activated carbon: impact on adsorption equilibrium

“…Close to 100% of the compound loaded on the GAG surface during both oxic and anoxic adsorption isotherm experiments was recovered by extraction with methanol and methylene chloride, indicating the absence of irreversible uptake under oxic conditions. Lim et al (25) calculated that a high activation energy of 12.5 Kcal/mol is required for the oxic coupling of phenol in an alkaline media and in the presence of a strong catalyst such as cuprous oxide. Therefore, the adsorption behavior of nitrophenols can be explained by the fact that activated carbon is a much weaker catalyst, that the adsorption experiments were conducted in a neutral medium, and that the addition of electron-withdrawing functional groups like NO2 increases the potential required to oxidize the organic compound (1 7 , 2 4 , 2 6 ) .…”

Catalytic wet air oxidation of phenol using active carbon: performance of discontinuous and continuous reactors

“…Results on homogeneous aerobic coupling of aqueous phenol catalysed by cuprous chloride at temperatures and partial pressures of oxygen below 60°C and 1 bar, respectively, reported a comparable activation energy of about 50 kJ mol À1 . 44 According to the authors the relatively low value was consistent with the free-radical nature of the reaction. Figure 8 compares the results obtained at same conditions of temperature and pressure in trickle bed reactor and slurry reactor.…”