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Experiments were conducted for the hydrogenolysis of CFC-12 (CCl2F2) to CH2F2 over bimetallic palladium catalysts (Pd-Bi, Pd-Ru) supported on activated carbon. The characteristics of the bimetallic palladium catalysts were examined with ICP, XRD, TPD, TEM, and N2 physisorption/H2 chemisorption and the Pd-F formation was identified by XPS analysis. The catalytic activity of the bimetallic palladium catalyst (Pd-Bi/C, or Pd-Ru/C) was superior to that of the monometallic palladium catalyst. The bimetallic palladium catalysts showed much higher conversion rates (more than 99% of it was converted) than did the monometallic palladium catalyst ( 320 ‡C). The bimetallic components maintained the good dispersion of the Pd on the activated carbon support.

An equilibrium study was conducted on the adsorption of chloropentafluoroethane (CFC-115, CF3CF2Cl) on activated carbon powder between 298.15 K and 373.15 K. Experimental data were fitted with several isotherm equations. Among the twoparameter equations, the BET equation showed the best results over the entire relative pressure range studied. When the pressure range was divided into two regions, a better result was obtained by applying the Langmuir equation in the lower pressure range and the BET equation in the higher relative pressure region. Among the threeparameter equations, the Langmuir-Freundlich equation gave better results than the RedrichPeterson equation. The isosteric heat of adsorption of CFC-115 on the activated carbon powder was estimated. It was found to have the same order of magnitude with the heat of condensation, which indicates that the adsorption was primarily due to physical forces.

The thermal degradation of polytetrafluoroethylene was studied in the helium flowing atmosphere and the temperature range 510–600°C. The products of the thermal degradation of polytetrafluoroethylene were analyzed by an on-line gas Chromatograph and the product distribution was obtained. The products consist of tetrafluoroethylene (TFE), perfluoropropene (PFP) and cyclic-perfluorobutane (c-PFB). Under most conditions the main product was TFE. The c-PFB was regarded as the secondary product formed from TFE because the formation of c-PFB strongly depended upon the degradation rate. However, the production of PFP was not related to the degradation rate, but it was influenced by diffusion limitation of gaseous product in the sample matrix. These phenomena were also verified with Curie-point pyrolyser. The results showed that the production of PFP reached a maximum point under diffusion limitation condition. The degradation mechanism of polytetrafluoroethylene was proposed in terms of unzipping mechanism and other mechanism like radical chain transfer reaction.

The thermal degradation of polytetrafluoroethylene in flowing helium atmosphere was studied in the temperature range 510–600C. The products of thermal degradation were analyzed by an on-line gas chromatography and the rates of degradation were obtained. At relatively lower temperatures (less than 530°C) the rate curves as a function of time showed two peaks. This phenomenon was explained in terms of diffusion limitation of the gaseous products. Further research was carried out by scanning electron microscopy (SEM) in order to observe the diffusion limitation and these facts were confirmed by observing the matrix of partially degraded polymer. The rate curves which have two peaks indicated that the diffusion limitation was disappeared above ca. 50% conversion. The activation energy in diffusion limitation free region was 78.1 kcal/mole and it was very similar to the result obtained by Madorsky (80.5 kcal/mole). The activation energy was also consistent with that obtained by thermogravimetry.

HCFC-133a (l-chloro-2,2,2-trifluoroethane) was thermally chlorinated in an integral reactor under atmospheric pressure in a temperature range between 573 and 723 K. From the analysis of the data it was confirmed that the reaction was a two-step series-parallel reaction and each step was a second-order reaction. The ratio of the second-step rate constant to the first-step rate constant did not change with temperature and its value was 1.13. The activation energy was 106 kJ/g-mol. These results indicate that the product distribution is the sole function of conversion of HCFC-133a.

The reaction mechanism for the methylformate formation on Cu/ZnO catalysts from methanol and CO was investigated by the labeling study with13C methanol. It was found that methylformate could be formed through two parallel reaction routes, i.e., methanol-formaldehyde reaction and carbonylation of methanol depending upon the catalyst composition as well as the reaction conditions. The major reaction route on the high ZnO-contcnt catalyst (Cu/ZnO=30/70) was found to be the methanol-formaldehyde reaction, and changed to the carbonylation reaction with the increase ol CO partial pressure. On the other hand, the major reaction route on the high Cu-content catalyst (Cu/ZnO=80/20) remained as methanol-formaldehyde reaction even under the high CO pressure.