Abstract: The preparation of vinyl halide monomer, and further to polyvinyl halide, starting from C1 compounds, involving conversion of methane or methanol to methyl halide; condensation of methyl halide to ethylene and co-product hydrogen halide; oxidative halogenation of ethylene to vinyl halide monomer; separation of vinyl halide monomer from any methyl halide present in the vinyl halide monomer stream; optional recycling of the methyl halide recovered to the condensation step; and recovery and optional recycling of the co-product hydrogen halide. Optionally, the vinyl halide monomer may be polymerized to polyvinyl halide to facilitate separation of the monomer from methyl halide. Methyl halide may be obtained via oxidative halogenation of methane in the presence of a rare earth halide or rare earth oxyhalide catalyst. Optionally, the methyl halide may be converted to methanol.

Abstract: The saw blade has a base body on which are mounted uncrossed teeth with cutting edges. The teeth are combined to form successive groups of at least three teeth and are disposed symmetrically to the longitudinal center plane of the base body. The teeth of one group increase in height from tooth to tooth while simultaneously decreasing in width.