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: The present invention relates to the production of catalysts and adsorbents which can be used for the removal of nitrogen oxides from exhaust gases containing the same.

Abstract: Copper-containing zeolites are prepared by subjecting a zeolite having the lattice spacings (d value) indicated in Table 1 as estimated by powder X-ray diffraction to ion exchange with copper ions in an aqueous solution containing a water soluble copper salt and ammonia. Nitrogen oxides can be decomposed with the copper-containing zeolite catalyst.

Abstract: Bromine is advantageously recovered from a free bromine-containing aqueous solution or gas by placing the solution or gas in contact with an adsorbent comprising a ZSM-5 zeolite having an SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio of at least 70 and heating the adsorbent at a temperature of at least 60.degree. C.

Abstract: Hydrogen ion-exchanged dealuminated mordenite having a reduced alumina content is advantageously prepared by filtering a crystallization slurry composed of a crystallization mother liquor and synthetic sodium type mordenite and obtained when the crystallization is completed, through a filter to form a wet cake layer of the sodium type mordenite; passing through the cake layer an aqueous solution of a mineral acid having a concentration of 0.1N to 5N; and then, washing the cake layer.

Abstract: Disclosed is a zeolite having a composition of the following formula: xM.sub.2/n O.Al.sub.2 O.sub.3.(5-10)SiO.sub.2.yH.sub.2 O wherein M is at least one cation having a valency of n, and x is 0.8-2 and y is 0-10, and exhibiting an X-ray powder diffraction pattern shown in Table 1. This zeolite is prepared by a process wherein a reaction mixture comprising a silica source, an alumina source, an alkali source, a potassium source and water and having a composition satisfying the following molar ratios: SiO.sub.2 /Al.sub.2 O.sub.3 =6-40, OH/SiO.sub.2 =0.3-1, K.sub.2 O/M.sub.2 O=0.1-0.9 (M: the total of alkali metals), and H.sub.2 O/SiO.sub.2 =10-70, is crystallized at 120.degree. to 200.degree. C. with stirring. The zeolite is also prepared by a process wherein a granular amorphous aluminosilicate containing aluminum in an amount of 4 to 22 wt. % as Al.sub.2 O.sub.

Abstract: A ferrierite type zeolite having a high purity and a high SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio is prepared by reacting simultaneously and continuously an aqueous sodium and/or potassium silicate solution with an aluminum-containing solution to obtain a homogeneous phase compound of a granular amorphous aluminosilicate containing Al in an amount of 3 to 14 wt. % as calculated as anhydrous Al.sub.2 O.sub.3 and Na and/or K in an amount of 1 to 17 wt. % as calculated as anhydrous Na.sub.2 O and/or K.sub.2 O; and then, crystallizing the homogeneous phase compound in the form of a slurry in water or in an aqueous sodium hydroxide and/or potassium hydroxide solution. The molar ratio of K.sup.+ to the total of (K.sup.+ +Na.sup.+) in the slurry is 0.1 to 0.9.

Abstract: A zeolite similar to ZSM-5, having lattice spacings (d-values), shown in Table 1, of the X-ray powder diffraction pattern, and a ferrierite zeolite are prepared by crystallizing a homogeneous phase compound of a granular amorphous aluminosilicate in water or in an aqueous solution of an alkali metal hydroxide and/or an alkali metal silicate.

Abstract: A stable calcium hypochlorite composition and a method for the preparation thereof. The composition has a calcium hypochlorite anhydride and/or a calcium hypochlorite dihydrate used as main constituent and comprises at least 60 wt % of calcium hypochlorite; at least 5 wt % of calcium hydroxide; at least 4 wt % of water content; and 5 wt % or less of than that calcium chloride. The composition is stable and decomposes only in a less degree at a high temperature and during storage over a long period.

Abstract: A dihydrate of calcium hypochlorite of a prismatic crystal shape in which the lengths of axes a, b and c thereof are in the ratios satisfying the following formulas (1), (2) and (3):0.5.ltoreq.b/a.ltoreq.2.0 (1)c/a.gtoreq.1.5 (2)c.gtoreq.5.mu. (3)and a method for the manufacture of the prismatic dihydrate. Further a method for the manufacture of a coarse dihydrate of calcium hypochlorite carried out by using the prismatic dihydrate of calcium hypochlorite as seed crystal.