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In this paper, glycolysis of toluenedilsocyanate based water-blown polyurethane foam has been examined by high performance liquid chromatography and gel permeation chromatography to determine the product distribution. Glycolysis with diethylene glycol (DEG) yields toluenediamlne (TDA), TDA mono-and di-DEG carbamates, a series of urea-linked mono-and di-DEG carbamate TDA oligomers, and polyether triol (polyol). The complexity of the product mixture suggests problems In applying simple glycolysis to the recovery of mixed and/or contaminated polyurethane wastes. A simpler product mixture results when water and a base catalyst are added to the glycolysis reaction (hydroglycolysis). Hydroglycolysis yields TDA and polyol as principal products. Data for the rate of the hydroglycolysis reaction are presented In the temperature range of 150 to 190 °C. These results suggest that hydroglycolysis could be used to recover polyols from mixed and/or contaminated water-blown polyurethane wastes.

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Kinetic and mechanistic investigations of liquid phase autcxidation of hexadecane at 120 to 190°C have shown that, in the early stages of oxidation, the initiation process involves homolytic decomposition of hydroperoxides. The values of a composite first order rate constant for this decomposition, k l , have been determined in stirred flow reactor experiments from the rate of formation of termination products and in batch reactor studies using inhibitor methods.Arrhenius parameters derived from these studies (log (A/s-') = 8.5 and E, = 26 kcal mol-') allow calculation of k l as a function of temperature. This permits determination of the rate of initiation as a function of hydroperoxide concentration and facilitates determination of absolute rate constants for other oxidation reactions occurring in this system.

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A kinetic and mechanistic study of the autoxidation of liquid pentaerythrityl tetraheptanoate (PETH) a t 180-22OOC has been carried out utilizing a stirred-flow reactor. The results are consistent with the occurrence of a chain reaction scheme similar to that proposed for n -hexadecane autoxidation, namely, the formation of monohydroperoxides by the intermolecular abstraction reaction (3), the formation of a,?-and cu,d-dihydroperoxides and a,?-and a,b-hydroperoxyketones by intramolecular peroxy radical abstraction reactions (4) and (4*), the bimolecular termination of peroxy radicals, reaction (61, and the rapid conversion of a,?-hydroperoxyketones to the corresponding cleavage acids and methyl ketones, reaction (7). Comparisons ofvarious rate parameters for the n-hexadecane and PETH systems reveal that the values of k7 and (k&l atom)/(2 hfi)1/2 are within experimental uncertainties identical for the two systems a t 180°C. The proposed reaction scheme includes the concurrent formation of hydroxy radicals and hydroperoxyketone species. The results of kinetic analysis and the experimentally observed isomer distributions of primary and secondary monohydroperoxide products a t high and low oxygen pressures suggest that ~6 0 % of the hydrogen abstractions from PETH a t high oxygen pressures occur by hydroxy radicals.

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