Abstract: A method for cleaning an exhaust gas containing at least one toxic component selected from the group consisting of arsine, phosphine, diborane and hydrogen selenide is disclosed. The method comprises contacting the toxic component with a molded cleaning agent having a composition consisting essentially of (1) cupric oxide and (2) at least one metal oxide selected from the group consisting of silicon oxide, aluminum oxide and zinc oxide and having a density of from about 1.5 to about 3.5 g/ml, said composition having a metal atomic ratio M/(M+Cu) in the range of from about 0.02 to about 0.7 wherein Cu represents a number of gram atom of copper and M represents a total number of gram atom of silicon, aluminum and/or zinc, to remove the toxic component from the exhaust gas.

Abstract: A solid detecting reagent for gaseous hydrides and a gaseous hydride detecting method are disclosed, said reagent comprising a basic copper carbonate as a color changing component and undergoing color change upon contact with at least one gaseous hydride selected from the group consisting of arsine, phosphine, diborane, hydrogen selenide, germane, monosilane, disilane and dichlorosilane. The reagent is applicable to all of these gaseous hydrides and, upon contact therewith, rapidly changes from an initial blue color to a black color, said black color standing for a long period of time.

Abstract: Trimellitic acid is produced in higher yield by liquid phase air oxidation of pseudocumene in acetic acid as a solvent in the presence of cobalt, manganese, and bromine as a catalyst, where the oxidation is carried out at two stages comprising a first stage of reaction at a temperature of 110.degree. to 170.degree. C. and a second stage of reaction at a temperature of 180.degree. to 240.degree. C. while maintaining a reaction pressure under a condition of the following formula throughout the reaction:1.20 Psolv.ltoreq.P.ltoreq.2.20 Psolvwherein P represents a reaction pressure as absolute pressure and Psolv represents a total vapor pressure of acetic acid and water present in a reaction system at a given reaction temperature.