Characterization of polyarylamide fibers by inverse gas chromatography.

Two types of commercial polyaramide fibers have been characterized by inverse gas chromatography. Using the fibers as stationary phases, adsorption isotherms for nonane, decane and undecane were obtained. Specific surface areas and isosteric heats of adsorption were also obtained by this method. Experimental results have been discussed as a function of hydrocarbon--fiber interaction and fiber crystallinity.

Catalytic hydrodechlorination of tetrachloroethylene over red mud.

Hydrodechlorination of tetrachloroethylene was investigated using red mud (RM, a by-product in the production of alumina by the Bayer process) as the catalyst. Use of RM as a hydrodechlorination catalyst is of interest from an industrial point of view because its cost is much lower than that of commercial catalysts. Hydrodechlorination reactions were carried out in a continuous fixed bed reactor. The influence of catalyst sulfiding, temperature (50-350 degrees C), pressure (2-10MPa), hydrogen flow rate and the presence of solvents (hexane, heptane, benzene and toluene) on the reaction was studied. Sulfided red mud is active as a hydrodechlorination catalyst, conversion of tetrachloroethylene increases as the pressure and temperature increase. The solvents did not influence the conversion, nor were side reactions involving the solvent observed. The kinetics of the reaction was studied at 350 degrees C and 10MPa, conditions for which mass transfer limitations were negligible. A good fit of a Langmuir-Hinselwood model to the experimental data was obtained.