Abstract: Lactones are prepared by catalytic carbonylation of oxiranes using a catalyst system comprising a) at least one cobalt compound as component A and b) at least one metal compound of the formula (I) as component B, MXxRn-x ??(I) where M is an alkaline earth metal or a metal of group 3, 4 or preferably 12 or 13 of the Periodic Table of the Elements, R is hydrogen or a hydrocarbon radical which may be substituted on the carbon atoms other than the carbon atom bound to M, X is an anion, n is a number corresponding to the valence of M and x is in the range from 0 to n, with n and x being selected so that the compound is uncharged, as catalyst.

Abstract: Lactones are prepared by catalytic carbonylation of oxiranes using a catalyst system comprising a) at least one carbonylation catalyst A comprising uncharged or anionic transition metal complexes of metals of groups 5 to 11 of the Periodic Table of the Elements and b) at least one chiral Lewis acid B, with the exception of [(salph)Al(THF)2][Co(CO)4], as catalyst.

Abstract: Disclosed is a method for producing an aqueous polymer dispersion, according to which unsaturated monomers are first polymerized by means of suitable catalysts, whereupon the obtained polymers that are swelled with all or some of the remaining unreacted monomers are added to surface-active substances and water in a last step in which the obtained polymers are not entirely separated from the remaining monomers.

Abstract: A process is described for preparing polyoxymethylene by contacting a formaldehyde source with a catalyst of the formula I [ML1aL2b]cm+Zc·m/nn???(I) where M is a metal of group VIII; L1 is a ligand having at least one ?-electron pair; each L2 is independently tetrahydrofuran or a ligand which is displaceable by tetrahydrofuran; Z is an anion; a is 1 or 2; b is an integer from 0 to 4; c is 1 or 2; and m and n are integers from 1 to 4.

Abstract: A process is described for preparing polyoxymethylene by contacting a formaldehyde source with a catalyst of the formula I [CpvMLw]m+Zm/nn???(I) where M is Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh or Ir, Cp is a cyclopentadienyl ligand C5H(5?u)R1u, where u is from 0 to 5 and R1 is alkyl, alkenyl, aryl, heteroaryl, aralkyl, COOR2, COR2, CN or NO2, and R2 is H, alkyl, aryl or aralkyl, v is 1 or 2, each L is independently a nitrile, CO or a ligand displaceable by CO, w is an integer from 0 to 4, Z is an anion, and m and n are each independently an integer from 1 to 3.

Abstract: A process for preparing thermoplastic poly(3-hydroxyalkanoates) with a molar mass greater than 6 000 g/mol and a melting point in the range from 70 to 170° C., by reacting an oxirane compound with carbon monoxide in the presence of a transition metal catalyst which has rhodium(0), nickel(0), iron(0), cobalt(0) or palladium(0) as central metal and has been chelated with neutral Lewis bases, and also in the presence of diisocyanates, ortho esters, acetals, anhydrides, P2O5, MgO, MgCl2, MgSO4, zeolites, or a mixture of these, at a pressure in the range from 1 to 250 bar and at from room temperature to 150° C.

Abstract: A polyalkylene carbonate, an alternating copolymer, may be prepared by the ring opening of an alkene oxide or an alkene oxide precursor in the presence of carbon dioxide or any substance delivering carbon oxide, in the presence of at least one catalyst comprising a metal-organic framework material, wherein said framework material comprises pores and a metal ion and an at least bidentate organic compound, said bidentate organic compound being coordinately bound to the metal ion.

Abstract: In a process for polymerizing dienes in a solvent comprising vinylaromatic monomers, the polymerization is carried out in the presence of a metal compound of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo or W as catalyst and a Lewis acid as cocatalyst and, if desired, an alkylating agent and, if desired, a regulator. This process can be used for preparing high-impact polystyrene, acrylonitrile-butadiene-styrene copolymers or methyl methacrylate-butadiene-styrene copolymers.