Abstract: A method for activating supported chromium oxide catalysts in which a chromium-containing catalyst on a silica-containing base is first heated in an oxidizing atmosphere at temperatures up to about 850.degree. C. and then cooled down. During the cooling step of the catalyst, the oxidizing atmosphere is replaced by a non oxidizing one, leading to an activated catalyst.A process for the polymerization of alpha-olefins, especially ethylene, in which at least one alpha-olefin is contacted, under polymerization conditions, with the catalyst activated by the method described above.

Abstract: A method for activating supported chromium oxide catalysts in which a chromium-containing catalyst on a silica-containing base is first heated in an oxidizing atmosphere at temperatures up to about 850.degree. C. and then cooled down. During the cooling step of the catalyst, the oxidizing atmosphere is replaced by a non-oxidizing one, leading to an activated catalyst. A process for the polymerization of alpha-olefins, especially ethylene, in which at least one alpha-olefin is contacted, under polymerization conditions, with the catalyst activated by the method described above.

Abstract: Disclosed are compounds of the formula, ##STR1## wherein the X's are the same and are hydrogen or --SO.sub.3 M,Y is hydrogen, C.sub.1-4 alkyl, C.sub.1-4 alkoxy, hydroxy, halogen, --COOM or --SO.sub.3 M,K.sub.1 and K.sub.2 are the same or different and are both radicals of a coupling component,either A.sub.1 is --SO.sub.3 M and one of B.sub.1 and C.sub.1 is --SO.sub.3 M, the other being hydrogen,or A.sub.1 and C.sub.1 are both hydrogen and B.sub.1 is --SO.sub.3 M, andM is hydrogen or a non-chromophoric cation, their production and use in dyeing anionic dyeable substrates, for example, natural and regenerated cellulose, natural and synthetic polyamides, polyurethanes, polypropylene modified to contain basic groups, anodized aluminum, paper and, particularly, leather.

Abstract: 1:2 Metal complexes of the formula ##STR1## in which each of X.sub.1 and X.sub.2, independently, is --COO-- or --O--,each of B.sub.1 and B.sub.2, independently, is a radical of a coupling component of the benzene or oxyquinoline series,M is a metal capable of forming a 1:2 complex and,each of ##STR2## independently, is the radical of a diazo component of the benzene series, with the proviso that at most one of such diazo component radicals contains a single sulpho group,and mixtures thereof with one or more of the corresponding symmetrical 1:2 metal complexes,which complexes and mixtures of complexes are in free acid or salt form and are useful as anionic dyes for dyeing and printing substrates such as natural and regenerated cellulose, natural and synthetic polyamides, polyurethanes and polymers modified to contain basic groups, especially leather.

Abstract: Complexes of the formula ##STR1## in which each of X.sub.1 and X.sub.2, independently, is --COO-- or --O--,each of B.sub.1 and B.sub.2, independently, is the radical of a coupling component of the benzene series containing up to two non-condensed benzene rings or a radical of a coupling component of the quinoline series, which coupling component radicals are free from acid groups,each of ##STR2## independently, is the radical of a diazo component of the benzene series in which the rings A.sub.1 and A.sub.2 shown are free from acid groups bound directly thereto,each of the floating sulpho groups on the naphthalene rings, independently, is in the 3- or 4-position, which complexes are free from fibre reactive groups and are in free acid or salt form, and mixtures of such complexes are useful as anionic dyestuffs for substrates comprising or consisting of, for example, natural or regenerated cellulose, natural or synthetic polyamides, leather, polyurethanes or polymers modified to contain basic groups.

Abstract: Disclosed are compounds of the formula, ##STR1## wherein THE X's are the same and are hydrogen or --SO.sub.3 M,Y is hydrogen, C.sub.1-4 alkyl, C.sub.1-4 alkoxy, hydroxy, halogen, --COOM or --SO.sub.3 M,K.sub.1 and K.sub.2 are the same or different and are both radicals of a coupling component,Either A.sub.1 is --SO.sub.3 M and one of B.sub.1 and C.sub.1 is --SO.sub.3 M, the other being hydrogen,Or A.sub.1 and C.sub.1 are both hydrogen and B.sub.1 is --SO.sub.3 M, andM is hydrogen or a non-chromophoric cation, their production and use in dyeing anionic dyeable substrates, for example, natural and regenerated cellulose, natural and synthetic polyamides, polyurethanes, polypropylene modified to contain basic groups, anodized aluminum, paper and, particularly, leather. The dyes are well-soluble in water, possess good resistance to acid, have relatively high substantivity especially to paper and leather and give good penetration dyeings with leather.Compounds of the formula ##STR2## wherein Q is --NH.sub.2, --NO.

Abstract: Compounds of the formula ##STR1## in which X signifies hydrogen, halogen or --SO.sub.3 M,M signifies hydrogen or a non-chromophoric cation, andK.sub.1 and K.sub.2, which are the same or different, each signifies a coupling component which has at least one free amino, enolic hydroxy or phenolic hydroxy group,And mixtures thereof, are useful as anionic dyes for natural and regenerated cellulose, natural and synthetic polyamides, polyurethanes, basically modified polyolefins, paper and, particularly, leather. The dyes are well-soluble in water, resistant to acid, have relatively low substantivity on leather, produce level dyeings and have no hardening effect on chrome-tanned leather and exhibit good fastness to light and wet treatments on paper. Also disclosed are compounds of the formula ##STR2## wherein M and X are as defined above, which are useful as intermediates.