Thermal properties phosgene

Phosgene proved to be an appropriate reactant to remove aluminium from the zeolite framework [1,2]. Detailed measurements have been carried out to investigate the adsorption of phosgene [3], the mechanism of dealumination by infrared spectroscopic and thermogravimetric methods [4], structural consequences [5], adsorption and catalytic properties of modified mordenites [6]. In addition an NMR study has been carried out, to measure the thermal stability of so-called hydroxy nests in H-mordenite dealuminated with phosgene [7]. 

Owing to their low flammability and excellent degreasing properties, the chlorinated hydrocarbons are commonly used as solvents in the laboratory, office and industrial workplaces. These materials, however, are particularly susceptible to thermal or photochemical decomposition to phosgene in normal environments. 

White solid with a chlorine-llke odor. Odor and eye irritation occur below the TLV and are adequate warning properties. Not combustible. Thermal-breakdown products include hydrogen chloride, phosgene, oxides at nitrogen, and chlorine gas. 

Tetrachloronaphthalene (Halowax [CAS 1335-88-2]) Causes chlor-acne and Jaundice, Stored In body fat. Dermal absorption occurs. 2 mg/m White to lightyellow solid. Aromatic odor of unknown value as a warning property. Vapor pressure is less than 1 mm Hg at 20°C (68°F). Thermal-breakdown products include hydrogen chloride and phosgene. 

Alternatively polycarbonate can be made in a melt process using diphenyl carbonate in lieu of phosgene. Mainly due to some issues with inferior properties such as color and thermal aging, the melt process was not used commercially to any significant extent until the early 1990s when these problems were solved. A 1 1 molar ratio of BPA and diphenyl carbonate is combined and heated in the presence of a catalyst. The BPA dissolves in the molten diphenyl carbonate and phenol is generated by a transesterification reaction. Vacuum is applied and removal of phenol shifts the equilibrium to the polycarbonate. The molten polycarbonate is extruded through a die and pelletized. 

Polycarbonates are polyesters of carbonic acid formed by reaction of diols (aromatic, aliphatic or a mixture of both) with a derivative of carbonic acid. The first preparations of polycarbonates were reported by Einhorn in 1898 [155], by reaction of phosgene with resorcinol or hydroquinone in a pyridine solution. Bischoff and van Hedenstrom in 1902 [156] obtained the same aromatic polycarbonates via transesterification with diphenyl carbonate (DPC). Thus the main routes to polycarbonates were established early, but the properties of the products seemed uninteresting. Around 1930 aliphatic polycarbonates were studied by Carothers and van Natta [157]. These carbonates have low melting points and thermal resistance and are not commercially interesting as stand-alone thermoplastics. Low molecular... 

Another polyester type, i.e., polycarbonate, is rather seldom solvolytically depolymerized because of losing (at least partially) carbonate groups/bonds obtained via phosgene route synthesis. Troev et al. [29] recently described PC chemical degradation with dialkyl phosphonates (dimethyl or diethyl) or triethyl phosphate. The products, oligomeric carbonates containing phosphorus atoms, can be considered as precursors for the modification of various polymers by improving their flame-retardant properties, thermal stability, and adhesion. 

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