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This work describes the reductive dehalogenation of carbon tetrachloride (CT) in a novel liquid-phase electrochemical reactor. The reactor consists of a cylindrical porous copper cathode with a concentric carbon-cloth anode wrapped around the cathode. The results show that CT destruction can be achieved, even in low conductivity solutions (i.e., deionized water), reaching 80% conversion of CT with a residence time of 10 min when a cathode potential of −0.4 V (versus a standard hydrogen electrode) is used. A mathematical model was formulated to simulate reactor performance. The model accounted for CT reductive dechlorination, hydrogen evolution on the cathode surface, and CT mass-transfer limitations. The equilibrium potential for CT reduction on the cathode surface was the only adjustable parameter. The model adequately represented experimental data under high-conductivity (2.2 S/m) and low-conductivity (0.05 S/m) conditions. The model results and experimental observations suggest that the entire cathode was active during CT reduction experiments, i.e., solution potential did not render portions of the cathode nonreactive, even in the low-conductivity experiments.

In this work we investigate the use of a continuous-flow, laboratory-scale electrochemical reactor for the destruction of aqueous-phase carbon tetrachloride (CT). The reactor consists of a porous copper foam cathode and a carbon-cloth anode section located downstream from the cathode. Experimental results show that appreciable conversions of CT can be obtained in the reactor, as long as the electrical conductivity of the liquid exceeds 1 S/m. At lower conductivities, most of the cathode exhibits low reactivity for CT-destruction due to relatively low charge transfer overpotentials. A mathematical model was formulated to predict reactor performance. The model takes into account the CT-reduction reaction and the hydrogen evolution reaction on the cathode surface as well as mass transfer limitations. Using the equilibrium potential for CT reduction as the only adjustable parameter, the model adequately represents experimental data for highly conductive solutions.

A procedure for collecting gas chromatographic fractions from a packed column and transferring them directly to a capillary column for subsequent mass spectral analysis is described. The fractions are trapped in 6 in lengths of 0.03 in, i.d., stainless steel capillary tubing and introduced without splitting into the capillary column through a modified inlet system while the capillary column is connected to the high vacuum system of the mass spectrometer. The technique is applicable to flavor chemistry studies in which the identify of compounds present in minute concentration in a flavor mixture is sought.

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