摘要:
The present invention relates to compounds with a metal-carbon bond suitable for insertion of acrylonitrile, a process for the preparation of these compounds and the use of these compounds for further insertions of acrylonitrile and/or other monomers.
摘要:
The invention refers to a linear, isotactic polymer which has a structure of one or several C2 to C20 olefins, of which the isotacticity, due to a statistic distribution of stereoscopic errors in the polymer chain, is within the range of from 25 to 60% of [mmmm] pentad concentration with the proviso that an arbitrary or rather regular sequence of isotactic and atactic blocks is excluded, the polymer having a mean molecular weight Mw within the range of from 100,000 to 800,000 gms/mol and a TG of from −50 to +30.
摘要:
In functionalized linear alternating carbon monoxide copolymers of carbon monoxide and at least one 1-alkene (A), compound (A) is an aryl derivative substituted with at least one terminal allyl and/or homoallyl moiety and containing one or more polar groups, with the proviso that 4-allylanisole is excluded.
摘要:
A process for preparing a compound of the formula I where R1 and R2 are hydrogen or C1-C4-alkyl and R3 is C1-C10-alkyl, phenyl or C1-C4-alkyl-substituted phenyl, comprises reacting a compound II with a compound of the formula III where X is chlorine, bromine or iodine, in the presence of a Friedel-Crafts catalyst in one step to give a compound I.
摘要:
A catalyst system suitable for the polymerization of C.sub.2 -C.sub.10 -alk-1-enes comprising, as active ingredients, a complex compound of metals in Sub-groups IV and V of the Periodic Table and an oligomeric alumoxan compound is obtained by a procedure in which metals in Sub-groups IV and V of the Periodic Table are mixed with the oligomeric alumoxan compound and the resulting mixture is then applied to finely divided polymer. The catalyst system of the invention can be isolated after manufacture and is particularly suitable for the gas-phase polymerization of C.sub.2 -C.sub.10 -alk-1-enes.
摘要:
Novel phenylcyclohexanes of the formula I ##STR1## in which n is 0 to 7, Q.sup.1 and Q.sup.2 are H, or one of these radicals is alternatively CH.sub.3, 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, --CF.sub.3, --CN, --OCF.sub.3 or --OCHF.sub.2, 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, Q.sup.1 =Q.sup.2 =H and simultaneously X=CN, Y and/or Z are F.
摘要:
The invention relates to a nematic liquid-crystal composition especially for active matrix displays with high voltage holding ratio, good low temperature stability and without reversed domains.
摘要:
Catalyst systems for the polymerization of C.sub.2 -C.sub.10 -alk-1-enes contain, as active components,a) a metallocene complex of the general formula I ##STR1## where M is titanium, zirconium, hafnium, vanadium, niobium or tantalum, X is halogen or C.sub.1 --C.sub.8 -alkyl, Y is carbon, phosphorus, sulfur, silicon or germanium, Z is C.sub.1 -C.sub.8 -alkyl, C.sub.3 -C.sub.10 -cycloalkyl or C.sub.6 -C.sub.10 -aryl, R.sup.1 and R.sup.2 are identical or different and are each C.sub.1 -C.sub.4 -alkyl, R.sup.3 to R.sup.6 are identical or different and are each hydrogen or C.sub.1 -C.sub.8 -alkyl, or two adjacent radicals R.sup.3 and R.sup.4 and R.sup.5 and R.sup.6 in each case together form a hydrocarbon ring system of 4 to 15 carbon atoms and n is 0, 1 or 2, andb) an open-chain or cyclic alumoxane compound of the general formula II or III ##STR2## where R.sup.7 is C.sub.1 -C.sub.4 -alkyl and n is from 5 to 30. The novel catalyst systems are particularly suitable for the preparation of polyalk-1-enes having high molecular weights.
摘要:
The invention relates to a liquid-crystalline medium for electrooptical display elements based on the ECB effect, containing two components A and B which themselves comprise one or more individual compounds, component A having clearly negative dielectric anistropy and giving the liquid-crystalline phase a dielectric anistrophy of .ltoreq.-0.3, and component B having pronounced nematogeneity and a viscosity of not more than 30 mPa.s at 20.degree. C., characterized in that component A contains one or more compounds containing a structural element ##STR1##
摘要:
The present invention relates to soluble catalyst systems for the polymerization of C.sub.2 - to C.sub.10 -alk-l-enes, containing, as active constituents,a) a metallocene complex of the general formula I ##STR1## where R.sup.1 and R.sup.2 are branched C.sub.4 - to C.sub.10 -alkyl, 5- to 7-membered cycloalkyl, which may itself be substituted by C.sub.1 - to C.sub.6 -alkyl, or are C.sub.6 - to C.sub.15 -aryl or aralkyl;R.sup.3 to R.sup.6 are C.sub.1 - to C.sub.8 -alkyl,M is titanium, zirconium, hafnium or vanadium,Y is silicon or germanium, andX is halogen or C.sub.1 - to C.sub.8 -alkyl,b) and an open-chain or cyclic aluminoxane compound of the general formula II or III ##STR2## where R.sup.7 is C.sub.1 -C.sub.4 -alkyl, and m is from 5 to 30. These catalyst systems are particularly suitable for the preparation of polypropylene and copolymers of propylene with lesser amounts of other C.sub.2 - to C.sub.10 -alky-l-enes.