摘要:
Amorphous polymers, including homopolymers and co-polymers, containing residues of vinyl cyclohexane and/or substituted vinyl cyclohexane are described. The polymers of the present invention have a syndiotactic configuration in which the quantity of diads is greater than 50.1% and less than 74%. The polymers of the invention have high transparency, low birefringence and high heat defection temperature, and can be used to prepare molded articles (e.g., optical data storage media and lenses) and films.
摘要:
Hydrogenation products of copolymers prepared by ring-opening metathetical polymerisation of a cyano-substituted norbornene and at least one multicyclic olefin, which contains 95.5 to 5 wt. % of the cyano-substituted norbornene incorporated in the polymer and in which at least 60% of the initially present olefinic double bonds have been saturated by hydrogenation and the preparation of the new hydrogenation products by polymerisation in the presence of a catalyst and optionally a chain transfer agent at -20.degree. C. to 100.degree. C. at atmospheric pressure in an inert solvent, followed by hydrogenation in the presence of a homogeneous or heterogeneous hydrogenation catalyst at 0.degree. C. to 200.degree. C. under a hydrogen pressure of 2 to 200 bar in an inert solvent.
摘要:
Process for hydrogenating aromatic polymers in the presence of catalysts, wherein a metal or mixture of metals from group VIII of the Periodic Table together with a support of silicon dioxide, aluminium dioxide or a mixture thereof is used as the catalyst, and the catalyst pore volume defined by pores of diameters between 100 and 1000 Å, measured by mercury porosimetry, is generally from 100 to 15%, in relation to the total pore volume, measured by mercury porosimetry.
摘要:
A process for the hydrogenation of aromatic polymers is disclosed. Accordingly, the solvent used comprise an ether that contains no &agr;-hydrogen atom on a carbon atom adjacent to the ether function. The process results in virtually complete hydrogenation of the aromatic units.
摘要:
A process for hydrogenating aromatic polymers is disclosed. The process entails using a supported catalyst wherein support contains alumina and where the catalyst comprise at least one metal of subgroup VIII of the Periodic Table. The catalyst is characterized in that the pore volume of the pores having diameters of 1000 to 10,000 Angstrom is 15 to 100% relative to the total pore volume, as determined by mercury porosimetry.
摘要:
A catayltic process for the hydrogenation of aromatic polymers is disclosed. The catalyst used in the process is a metal or mixture of metals of sub-group VIII of the periodic table together with a support of silicon dioxide, aluminum oxide or a mixture thereof. The catalyst, having pores is characaterized in that the pores having diameters of 100 to 1,000 Å constitute less than 15 percent of the total volume of pores. The hydrogenation, that is carried out in the presence of at least one oxygen-containing hydrocarbon is characterized in that it is essentially complete and without significant degradation of molecular weights.
摘要:
The invention provides a process for preparing diaryl carbonates from dialkyl carbonates and aromatic hydroxyl compounds using at least two reaction columns, a process section for recovering the dialkyl carbonate used in the reaction and for removing the alcohol of reaction, one or more process steps for removing the by-products obtained in the process which have a boiling point between that of the dialkyl carbonate and that of the alkyl aryl carbonate formed during the preparation of the diaryl carbonate, and a process step for further purification of the diaryl carbonate obtained from the reaction columns.
摘要:
The invention relates to bimetallic complexes in which the ligand contains a salophen unit which complexes copper, manganese or cobalt and a phenanthroline unit which complexes palladium and the two systems are linked by a continuous conjugated system. The invention further relates to the use of these bimetallic complexes as catalysts for the oxidative carbonylation of aromatic hydroxy compounds to form diaryl carbonates, a process for preparing diaryl carbonates using the bimetallic complex as catalyst and also diaryl carbonates prepared by oxidative carbonylation of aromatic hydroxy compounds using the bimetallic complexes of the invention as catalysts.
摘要:
The invention relates to a process for the pretreatment of material surfaces in order to minimize the interaction between polycarbonate and metal and, in the processing and synthesis of polycarbonate, to obtain a high-quality polymer which in particular does not become discolored and is free of insoluble constituents.
摘要:
The present invention relates to a process for continuously preparing diaryl carbonates from dialkyl carbonates and at least one monohydroxyl compound in the presence of catalysts, and to the use thereof for preparation of polycarbonates. The alkylene glycol obtained in the preparation of the dialkyl carbonate used is recycled by oxidative carbonylation with carbon monoxide in the presence of a catalyst to give the cyclic alkylene carbonate which is in turn converted to the dialkyl carbonate. More particularly, the process utilizes the alkylene glycol obtained for the diphenyl carbonate preparation process (DPC process).