Abstract: The present invention relates to poly-(C.sub.2 -C.sub.10 -.alpha.-olefine)-carboxylic acids of Mw (weight average) 2000 to 350,000, to their preparation by oxidative degradation of polyolefines or by reaction of "Living" polyolefines with CO.sub.2, to their conversion into poly-(C.sub.2 -C.sub.10 -.alpha.-olefine)-carbonyl halides and to their use for preparing polyolefine/polycarbonate block copolymers and the block copolymers obtainable by the process according to the invention.

Abstract: Syndiotactic 1,2-polybutadiene of high quality may be obtained in excellent yield by solution polymerization of butadiene-(1,3) in hydrocarbons, using organometallic mixed catalysts composed of trialkylaluminium, hydrocarbon-soluble chromium-III compounds and a dialkylphosphite corresponding to the formula ##STR1## wherein R denotes straight chained or branched C.sub.1 -C.sub.8 -alkyl andR.sub.1, R.sub.2 and R.sub.3 denote methyl or ethyl orR and R.sub.1 together form a methylene group.

Abstract: A gas-cooled nuclear reactor whose nuclear-fuel elements are constituted by graphite-encapsulated nuclear fuel particles and have graphite coatings is shut down in accordance with the present invention by introducing into the primary coolant gas circulation, a gadolinium-containing substance which is dispersed in the primary cooling gas before the latter enters the space between the fuel elements within the reactor core so that the gadolinium-containing substance is at least partly deposited on the free graphitic surfaces of the fuel elements.

Abstract: A catalyst comprising(a) a reaction mixture formed by reacting M(RCO.sub.2).sub.3 with AlR.sub.3.sup.1,(b) AlR.sub.3.sup.2 and/or HAlR.sub.2.sup.2 and(c) a Lewis acidwherein M denotes a trivalent rare earth element with an atomic number of 57 to 71, R denotes a saturated or unsaturated, straight chain or branched chain alkyl group having 1 to 20 C-atoms which may be substituted one or more times with cycloalkyl having 5 to 7-atoms and/or phenyl, the carboxyl group being attached to a primary, secondary or tertiary C-atom; a cycloalkyl group having 5 to 7 ring carbon atoms, which may be substituted one or more times with alkyl groups having from 1 to 5 C-atoms; or an aromatic group having from 6 to 10 ring carbon atoms, which may be substituted one or more times with alkyl groups having 1 to 5 C-atoms, and R.sup.1 and R.sup.2 are identical or different, straight chain or branched chain alkyl groups having from 1 to 10 C-atoms. Said catalyst may be used for polymerizing diene monomers in solution.

Abstract: A catalyst comprising(a) a reaction mixture formed by reacting M(RCO.sub.2).sub.3 with AlR.sub.3'.sup.1(b) AlR.sub.3.sup.2 and / or HAlR.sub.2.sup.2 and(c) a Lewis acidwherein M denotes a trivalent rare earth element with an atomic number of 57 to 71, R denotes a saturated or unsaturated, straight chain or branched chain aliphatic hydrocarbon group having 1 to 20 C-atoms which may be substituted one or more times with cycloalkyl having 5 to 7-atoms and/or phenyl, the carboxyl group being attached to a primary, secondary or tertiary C-atom; a cycloalkyl group having 5 to 7 ring carbon atoms, which may be substituted one or more times with alkyl groups having from 1 to 5 C-atoms; or an aromatic group having from 6 to 10 ring carbon atoms, which may be substituted one or more times with alkyl groups having 1 to 5 C-atoms, and R.sup.1 and R.sup.2 are identical or different, straight chain or branched chain alkyl groups having from 1 to 10 C-atoms.

Abstract: A catalyst composition comprising (a) TiI.sub.4 and/or TiOR.sup.1 I.sub.3, (b) AlR.sub.3 and/or HAlR.sub.2 and (c) TiXCl.sub.3 can be used for polymerizing butadiene. Said catalyst can be obtained by mixing the components a, b and c in any order at temperatures from -10.degree. to +80.degree. C. R' represents C.sub.1-8 alkyl and X represents a C.sub.1-12 alkoxy radical optionally substituted one or more times by halogen, C.sub.6 or C.sub.7 cycloalkyl and/or phenyl, a C.sub.5-7 cycloalkoxy radical optionally substituted one or more times by C.sub.1-5 alkyl groups, a phenoxy group corresponding to the formula ##STR1## wherein R.sub.2 and R.sub.6 can be the same or different and are hydrogen or C.sub.1-5 alkyl, a carboxyl group having the formula R.sup.7 --COO wherein R.sup.7 is C.sub.1-12 alkyl optionally substituted one or more times by halogen, C.sub.5-7 cycloalkyl and/or phenyl, a C.sub.5-7 cycloalkyl radical optionally substituted one or more times by C.sub.1-5 alkyl groups, or phenyl.

Abstract: A process for the production of strictly alternating copolymers of trans-1,4-butadiene and propylene units by the solution copolymerization of butadiene and propylene with vanadium-containing organometallic mixed catalysts, wherein vanadyl dialkoxy halides of which the alkoxy groups are branched in the 2-position to the oxygen atom are used as the vanadium compounds.

Abstract: Uranium-containing mixed catalysts containing uranium in the formal oxidation state +4 as uranium salts of carboxylic acids, a Lewis acid, and an organometallic aluminum compound are prepared and can be used for stereospecific polymerization of diolefins or mixtures of diolefins and monoolefins.