Abstract: Benzopyrans of the formula ##STR1## where X is a radical ##STR2## and R.sup.1, R.sup.2, R.sup.3, R.sup.4 and the ring A have the meanings stated in the description, a process for their preparation, and their use in pressure-sensitive or heat-sensitive layers.

Abstract: A thermoplastic molding material contains, in each case based on the molding material comprising A+B,A from 80 to 60% by weight of a hard matrix composed of polystyrene andB from 20 to 40% by weight of a soft phase which is obtainable by polymerization of styrene in the presence of a linear styrene/butadienne block copolymer which has an ill defined transition, contains from 35 to 45% by weight of styrene and from 65 to 55% by weight of butadiene and has a block polystyrene content of from 25 to 35% by weight, the soft phase being uniformly distributed in the hard matrix and having a particle diameter of less than 0.8 .mu.m.The typical features of the said molding material are that the median particle diameter d.sub.50 (volume average of the soft phase B is from 0.25 to 0.38 .mu.m, the width of the particle size distribution, (d.sub.95 14 d.sub.5), is from 0.2 to 0.6 .mu.m, the d.sub.60 value is from 0.26 to 0.40 .mu.m and the d.sub.90 value is from 0.40 to 0.75.

Abstract: Homo- or copolymers which have terminal mercapto groups, are composed of one or more monomers from the group consisting of butadiene, isoprene and styrene and are obtained by anionic polymerization of one or more of the stated monomers in the presence of one or more organolithium compounds followed by reaction (of the living anions) with an episulfide of the general formula I ##STR1## where R is hydrogen, alkyl of 1 to 18 carbon atoms or aryl of 6 to 10 carbon atoms, with the formation of one or more primary or secondary mercapto groups at the end of the polymer chain(s) are prepared by a process in which a thiolcarboxylic acid of the general formula II ##STR2## where R.sup.1 is hydrogen, alkyl of 1 to 10 carbon atoms or --CH.sub.2 --COOH and R.sup.2 is 0 or from 1 to 10 CH.sub.2 units, is added directly to the resulting reaction mixture in an amount of from 0.

Abstract: Compact pore-free silicon carbide moldings are produced by compressing amorphous silicon carbide powder in the absence of sintering assistants at from 1400.degree. to 1800.degree. C. and under from 100 to 2000 kp/cm .sup.2 to give dense, glassy moldings. In a subsequent stage the resulting glassy moldings are converted into crystalline .alpha.-silicon carbide at from 1950.degree. to 2200.degree. C.

Abstract: 4-methyl-4-phenyl-1-pentanals of the general formula I ##STR1## where R.sup.1 is hydrogen or C.sub.1 -C.sub.4 -alkyl and R.sup.2 is hydrogen or methyl, with the exception of 4-methyl-4-phenyl-1-pentanal, and the use of the methylphenylpentanals of the formula I for imparting fragrance properties to, or improving or modifying the fragrance properties of, perfumes and perfumed products, and the preparation of these compounds by hydroformylation of the corresponding 3-methyl-3-phenyl-1-butenes of the general formula II ##STR2## and, if required, subsequent reaction with formaldehyde and partial hydrogenation.

Abstract: Disazothiphene dyes of the formula ##STR1## where X is an electron withdrawing group, Z is an electron withdrawing group, D is the radical of a diazo component and K is the radical of a coupling component, are highly suitable for dyeing synthetic fibers, in particular polyesters.

Abstract: This invention relates to a process for the preparation of non-cellular or cellular polyurethane elastomers by the reaction of(a) an organic polyisocyanate, preferably in the form of NCO groups containing prepolymers and/or modified urethane group containing organic polyisocyanates with(b) a higher molecular weight compound having at least two reactive hydrogen atoms,(c) a polyester polyol containing tin and/or titanium compounds as catalysts, and optionally(d) a chain extending agent and/or crosslinking agent in the presence of(e) blowing agents,(f) auxiliaries and/or additiveswhereby from 0.1 to 10 parts by weight, based on 100 parts by weight of the (b) component, of a polyester polyol is used as a catalyst, which is prepared by the polycondensation of organic polycarboxylic acid with multivalent alcohols in the presence of from 0.002 to 5 weight percent, based on the weight of the polycondensation mixture, of a titanium and/or tin compound used as a catalyst at temperatures from 150.degree. to 200.degree.

Abstract: Pure hydroxylammonium salts of fatty acids of 1 to 4 carbon atoms are prepared by reacting hydroxylammonium sulfate and alkali metal salts of fatty acids with 1 to 4 carbon atoms in solution at elevated temperatures and separating off the hydroxylammonium salts of fatty acids of 1 to 4 carbon atoms by(a) reacting hydroxylammonium sulfate and alkali metal salts of fatty acids of 1 to 4 carbon atoms in solution in water or alkanols of 1 to 3 carbon atoms or mixtures thereof at 20.degree.-70.degree. C.,(b) evaporating the solvent out of the reaction mixture to obtain a dry residue,(c) isolating the hydroxlammonium salts of fatty acids of 1 to 4 carbon atoms from the dry residue thus obtained by sublimation under reduced pressure.

Abstract: High-impact polyamide molding compositions contain as essential components(X) from 40 to 98% by weight, based on (X)+(Y), of a thermoplastic polyamide,(Y) from 2 to 60% by weight, based on (X)+(Y), of a rubberlike polymer which contains, as copolymerized units, an acrylic or methacrylic ester or an unsaturated carboxylic acid,(Z) from 0.001 to 2% by weight, based on (X)+(Y), of a metal compound selected from the group consisting of(Z.sub.1) salts of divalent, trivalent or tetravalent metals with C.sub.2 -C.sub.4 -carboxylic acids,(Z.sub.2) oxides of germanium or antimony and(Z.sub.3) alkyl orthotitanates and dialkyltin dilaurates.

Abstract: Surfactant-modified metal catalysts which can be used in a process for hydrogenating mediators.

Abstract: Disk-shaped nickel-plated aluminum substrates which are used as bases in the production of magnetic recording disks having a magnetizable metallic layer are surface treated by polishing and texturing.

Abstract: Chlorate is removed from aqueous caustic soda by reducing with iron pentacarbonyl and separating off the resulting iron oxide containing precipitate.

Abstract: A process for the preparation of esters of tetrahydropyran-4-carboxylic acid of the general formula I, where R.sup.1 is an alkyl, cycloalkyl, or aryl group, by treating butyrolactones of the general formula II, where R.sup.2 is a hydrogen atom, an alkyl group, or an acyl group --CO--R.sup.3, R.sup.3 being a hydrogen atom or an alkyl group with from 1 to 6 carbon atoms, with alcohols of the general formula III at temperatures of from 150.degree. C. to 400.degree. C. in the presence of acid catalysts.

Abstract: Compounds useful as stabilizers have the general formula I ##STR1## where the radicals are as defined in claim 1.

Abstract: Polyaryl ether ketones are prepared by reacting aromatic dihydroxy compounds with aromatic dihalogen compounds in polar aprotic solvents in the presence of alkali metal carbonates, in particular by reacting aromatic dihydroxy compounds I ##STR1## or ring-substituted C.sub.1 -C.sub.8 -alkyl, C.sub.1 -C.sub.8 -alkoxy, aryl, chlorine or fluorine derivatives thereof, n and m each being 0 or 1, with aromatic dihalogen compounds ##STR2## or ring-substituted C.sub.1 -C.sub.8 -alkyl, C.sub.1 -C.sub.8 -alkoxy, aryl, chlorine or fluorine derivatives thereof, r and s each being 0 or 1, A being oxygen or a chemical bond and X being chlorine or fluorine.

Abstract: Polyoxymethylene molding materials having improved heat stability and consisting of(A) one or more polyoxymethylene homopolymers and/or copolymers and(B) one or more antioxidants having a sterically hindered phenolic structure,(C) with or without additives, contain(D) as an additive, one or more alkaline earth metal silicates and/or alkaline earth metal glycerophosphates, advantageously in an amount of from 0.002 to 2.0% by weight, based on the weight of component (A),for improving the heat stability, reducing the tendency to discoloration and minimizing the free formaldehyde content.To prepare the novel polyoxymethylene molding materials, the components are advantageously melted in an extruder at from 150.degree. to 260.degree. C.The polyoxymethylene molding materials are useful for the production of films or, preferably, moldings, which are used, for example, in the automotive, electrical appliances and electronics industries.

Abstract: 2,2-Disubstituted 3-chloropropionic esters I ##STR1## where R.sup.1 and R.sup.2 are each C.sub.1 -C.sub.6 -alkyl, C.sub.2 -C.sub.6 -oxaalkyl, C.sub.2 -C.sub.6 -alkenyl, C.sub.2 -C.sub.6 -oxaalkenyl, aryl or C.sub.7 -C.sub.12 -aralkyl or R.sup.1 -C-R.sup.2 is 5-, 6- or 7-membered ring, R.sup.3 is C.sub.2 -C.sub.6 -oxaalkyl, C.sub.2 -C.sub.6 -alkenyl, C.sub.2 -C.sub.6 -oxaalkenyl or C.sub.7 -C.sub.12 -aralkyl, are prepared by converting 2,2-disubstituted 3-hydroxypropanals II ##STR2## into the esterdiol III ##STR3## reacting this esterdiol III in the presence of a transesterification catalyst with an alcohol R.sup.3 OH to give the 3-hydroxyester IV ##STR4## reacting the hydroxyester IV with a stoichiometric or greater than stoichiometric amount of the thionyl chloride and thermally decomposing the product to give the chloropropionic ester I.

Abstract: Sulfatobetaines are prepared by reacting an adduct of a base having a tertiary N atom and sulfur trioxide with an alkylene oxide in the presence of an alkylene carbonate as a solvent.

Abstract: Sizing agents for paper are based on finely divided aqueous dispersions of copolymers obtainable by copolymerizing from 40 to 140 parts by weight of a monomer mixture of(a) from 20 to 65% by weight of (meth)acrylonitrile,(b) from 35 to 80% by weight of one or more acrylates of monohydric saturated C.sub.3 -C.sub.8 -alcohols and(c) from 0 to 10% by weight of other ethylenically unsaturated copolymerizable monomers,the weight percentages (a), (b) and (c) always adding up to 100, in the manner of an emulsion polymerization in 100 parts by weight of an aqueous solution containing in solution from 2.7 to 15% by weight of a degraded starch having a viscosity n.sub.i from 0.04 to less than 0.12 dl/g at from 40.degree. to 100.degree. C. in the presence of a peroxide initiator.

Abstract: Polymers and copolymers of conjugated dienes and aromatic vinyl compound which have a carboxyl end group and are present as salts, the salts containing metal cations or metal cation complexes which are bivalent or polyvallent and also a process for preparing such salts of polymers which contain carboxyl end groups and their use for modifying thermoplastic materials or as vulcanizable materials.