摘要:
The present invention relates to a process for preparing carbonates by reacting propylene oxide, ethylene oxide, styrene oxide and/or cyclohexene oxide with carbon dioxide in the presence of one or more catalysts of the formula I where R1 is hydrogen, C1-C6-alkyl, C1-C6-haloalkyl, NR′4—(CH2)2-6—where R′ is C1-C6-alkyl; R2 is hydrogen, C1-C4-alkyl, C1-C4-haloalkyl, halogen, amino, nitro, C1-C6-alkoxy or cyano; R3, R4 are each hydrogen or together are a butadienylene moiety which bears the R5 substituent; R5 is C1-C4-alkyl, C1-C4-haloalkyl, halogen, amino, nitro, C1-C6-alkoxy or cyano; M is Zn(II), Mg(II), Cr(II), Cr(III), Co(II), Co(III), Fe(II) or Fe(III); and X1, X2 are each OCOCH3, OCOCF3, OSO2C7H7 or halogen. More particularly, the invention relates to a process for preparing cyclic carbonates, and to a process for preparing aliphatic polycarbonates using these catalysts I, and to particularly preferred catalysts of the formulae Ia and Ib.
摘要:
A macrocycle based on β-diketimines, a process for preparing the inventive macrocycle, an uncharged macrocyclic dimetallic complex based on the inventive macrocycle, and a process for preparing the uncharged macrocyclic dimetallic complex, the use of the uncharged macrocyclic dimetallic complex as a polymerization catalyst in the polymerization of carbon dioxide with one or more epoxides, a process for preparing polycarbonates by reacting carbon dioxide with one or more epoxides in the presence of the inventive uncharged macrocyclic dimetallic complex, and a polycarbonate prepared by the process according to the invention.
摘要:
A macrocycle based on β-diketimines, a process for preparing the inventive macrocycle, an uncharged macrocyclic dimetallic complex based on the inventive macrocycle, and a process for preparing the uncharged macrocyclic dimetallic complex, the use of the uncharged macrocyclic dimetallic complex as a polymerization catalyst in the polymerization of carbon dioxide with one or more epoxides, a process for preparing polycarbonates by reacting carbon dioxide with one or more epoxides in the presence of the inventive uncharged macrocyclic dimetallic complex, and a polycarbonate prepared by the process according to the invention.
摘要:
Disclosed are novel liquid-crystal compounds, processes and intermediates for the preparation thereof, the use thereof for optical, electro-optical and electronic purposes, in particular in liquid-crystal (LC) media and LC displays, and to LC media and LC displays containing the same.
摘要:
The invention relates to a matrix liquid crystal display containing integrated non-linear elements and a liquid crystal mixture which has a particularly high resistivity.
摘要:
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.
摘要:
The invention relates to a catalytical process for preparing poly(3-hydroxyalkanoates) by copolymerizing an oxirane compound with carbon monoxide in the presence of a) at least one single- or multicenter neutral transition metal complex (A) based on a metal of groups 5 to 11 of the Periodic Table of the Elements, in which the metal center(s) is/are present in the formal oxidation state 0, and/or b) at least one single- or multicenter anionic transition metal complex (B) based on a metal of groups 5 to 11 of the Periodic Table of the Elements, where multicenter transition metal complexes have metal centers which, without exception, are of the same transition metal, which comprises carrying out the copolymerization in the presence of at least one nucleophile other than hydroxy-substituted pyridine compounds.
摘要:
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.
摘要:
Novel phenylcyclohexanes of the formula I in which n is 0 to 7, Q1 and Q2 are H, or one of these radicals is alternatively CH3, r is 0, 1, 2, 3, 4 or 5, A is trans-1,4-cyclohexylene, 1,4-phenylene, 3-fluoro-1,4-phenylene or a single bond, X is F, Cl, —CF3, —CN, —OCF3 or —OCHF2, and Y and Z are each, independently of one another, H or F, with the proviso that, in the case where A is a single bond, Q1=Q2=H and simultaneously X=CN, Y and/or Z are F.