Abstract: To provide a novel lithium styrene sulfonate which is capable of solving a problem of an increase of the production cost due to drying under atmospheric pressure or reduced pressure at a temperature of at least 40° C. and a problem of polymerization of lithium styrene sulfonate. The lithium styrene sulfonate is characterized in that when measured by using a Thermogravimetric-Differential Thermal Analyzer under measuring condition of heating at a temperature raising rate of 2° C./min in a nitrogen stream, the temperature at the top of the main endothermic peak in a range of from 80 to 170° C., is at least 120° C.

Abstract: To provide a novel lithium styrene sulfonate which is capable of solving a problem of an increase of the production cost due to drying under atmospheric pressure or reduced pressure at a temperature of at least 40° C. and a problem of polymerization of lithium styrene sulfonate. The lithium styrene sulfonate is characterized in that when measured by using a Thermogravimetric-Differential Thermal Analyzer under measuring condition of heating at a temperature raising rate of 2° C./min in a nitrogen stream, the temperature at the top of the main endothermic peak in a range of from 80 to 170° C., is at least 120° C.

Abstract: A method for removing nitrogen oxides from an oxygen-rich exhaust gas containing nitrogen oxides and hydrocarbons comprising bringing the oxygen-rich exhaust gas into contact with a catalyst comprising (1)(i) a zeolite containing an apatite compound and having an SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio of at least 15 and (ii) at least one active metal or (2)(ii) a zeolite containing an apatite compound and having an SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio of at least 15, (ii) an alkaline earth metal and (iii) at least one active metal.

Abstract: A catalyst, for purifying an exhaust gas, is a zeolite catalyst for removing nitrogen oxides, carbon monoxide and hydrocarbons from an oxygen-rich exhaust gas containing the nitrogen oxides, carbon monoxide and hydrocarbons, wherein the zeolite has an SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio of 10 or more and contains nickel, or wherein the zeolite has an SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio of 15 or more, and contains nickel and a rare earth metal or an alkaline earth metal.

Abstract: A process for removing nitrogen oxides from oxygen rich exhaust gas containing nitrogen oxides and hydrocarbons using a catalyst composed of at least one active metal and zeolite having a molar ratio of SiO.sub.2 /Al.sub.2 O.sub.3 of at least 15, treated with a vapor of at least one silicon compound selected from alkylchlorosilanes, alkoxysilanes, alkoxyalkylsilanes, and silicon tetrachloride or treated with an alkoxysilane or silicon tetrachloride in an organic solvent.

Abstract: A catalyst for purifying an exhaust gas comprising a zeolite catalyst ion exchanged with cobalt and at least one alkaline earth metal and a zeolite catalyst ion-exchanged with copper, provided on an inlet side of an exhaust gas stream and an outlet side of the exhaust gas respectively, or randomly present in a mixed state.

Abstract: A method for purifying an exhaust gas containing an excess amount of oxygen, to remove nitrogen oxides, carbon monoxide and hydrocarbons therefrom, by bringing a catalyst into contact with the exhaust gas, the catalyst comprising a zeolite ion-exchanged with (a) cobalt or (b) both cobalt and at least one metal selected from the group consisting of alkaline earth metals and rare earth metals, the zeolite being selected from the group consisting of ferrierite, ZSM-5, ZSM-11, ZSM-12 and ZSM-20, and having a silica-to-alumina molar ratio of from 15 to 1,000.

Abstract: Nitrogen oxides are removed from an oxygen rich exhaust gas containing nitrogen oxides and hydrocarbons by bringing the oxygen rich exhaust gas into contact with a catalyst composed of phosphorus and at least one active metal contained in a zeolite having a molar ratio of SiO.sub.2 /Al.sub.2 O.sub.3 of at least 15.

Abstract: A method for purifying an exhaust gas using a transition metal-containing zeolite having a high hydrothermal stability having the formula, in terms of a molar composition of oxides:aA.sub.2 O.bM.sub.2/n O.Al.sub.2 O.sub.3.cSiO.sub.2.dH.sub.2 O(I)wherein a is 0.2 to 1.0, b is more than 0 but not more than 1.5, c is at least 10, d is an arbitrary number, A is potassium or cesium, M is a transition metal and n is a valence number of the metal M.

Abstract: A catalyst for reducing nitrogen oxides from an exhaust gas containing the same in an oxygen rich atmosphere comprising (i) a zeolite having a molar ratio of SiO.sub.2 /Al.sub.2 O.sub.3 of at least 10, (ii) copper, and (iii) a rare earth ion, an alkaline earth metal and/or a valence variable metal.

Abstract: A catalyst for purifying an exhaust gas comprising: a crystalline aluminosilicate containing a rare earth or alkaline earth metal produced by allowing a rare earth or alkaline earth metal salt to exist in reactants for a synthesis of a crystalline aluminosilicate, and introduced therein, at least one element selected from the consisting of the group Ib metals and VIII metals of the periodic table.

Abstract: A method for cleaning an exhaust gas, entailing bringing the exhaust gas into contact with a crystalline aluminosilicate having a primary particle size of not less than 0.5 micron, containing one or more kinds of metal ions selected from the group of metals of Group Ib and Group VIII of the periodic table in an amount ranging from about 0.2 to 0.8 equivalent relative to one gram atom of aluminum, and having a mole ratio of SiO.sub.2 /Al.sub.2 O.sub.3 of not less than about 20.

Abstract: Synthetic mazzite having a small particle size is advantageously prepared by making present a transparent liquid phase compound in a starting mixture containing a silica source, an alumina source, an alkali source and a tetramethylammonium source.The transparent liquid phase compound is obtained by mixing an aqueous solutuion of an alkali metal silicate, an aqueous solution of an alkali metal aluminate, an aqueous solution of an alkali metal hydroxide and a tetramethylammonium compound and aging the mixture.