摘要:
The invention relates to a process for extruding plastic compositions. The process in particular relates to the conveying, kneading and/or mixing of plastic compositions, in particular of polymer melts and mixtures of polymer melts, above all thermoplastics and elastomers, particularly preferably polycarbonate and polycarbonate blends, also with the incorporation of other substances such as for example solids, liquids, gases or other polymers or other polymer blends.
摘要:
The invention relates to polycarbonates with extremely low residual levels of volatile constituents and thermal degradation products, and also improved optical properties, especially Yellowness Index (YI) and good thermal stability, from solvent-containing polymer melts. The invention further relates to an apparatus and a process for preparing these polycarbonates with the aid of a devolatilizing extruder with at least three devolatilizing zones, and zones for introducing entraining agent into dispersion are present upstream of at least three devolatilizing zones.
摘要:
The invention relates to a process for extruding plastic compositions, in particular polymer melts and mixtures of polymer melts, above all thermoplastics and elastomers, particularly preferably polycarbonate and polycarbonate blends, also with the incorporation of other substances such as for example solids, liquids, gases or other polymers or other polymer blends with improved optical characteristics, with the assistance of a multi-screw extruder with specific screw geometries.
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:
A platinum metal-containing supported catalyst in which the support contains mixed oxides of metals, transition metals and semiconductor elements, which can act as redox catalysts under the reaction conditions is disclosed. Also disclosed is the preparation of these catalysts and their use in a process for preparing diaryl carbonates.
摘要:
In the process for preparing an aromatic carbonate from an aromatic hydroxy compound, CO and O.sub.2 in the presence of a quaternary salt and a base, use is advantageously made of supported catalysts which, in the reaction-ready state, contain a platinum metal, a platinum metal compound or a complex containing a platinum metal compound on a support comprising a metal oxide whose metal can occur in a plurality of oxidation states.
摘要:
In the process for the production of diaryl carbonates by oxidative carbonylation of the underlying aromatic hydroxy compounds in the presence of a catalyst containing a platinum group metal, a co-catalyst, a quaternary salt and a base, the catalyst is used as a supported catalyst in a stationary arrangement or in the fluid phase and the reaction is performed in the condensed phase. The co-catalyst is preferably also attached to the support.
摘要:
In the preparation of diaryl carbonates from an aromatic hydroxy compound, CO and O.sub.2, use is made not only of a quaternary salt, a base, a platinum metal catalyst and a cocatalyst, but additionally of a heterogeneous promoter which is a compound of the formulaA.sub.x B.sub.y C.sub.z,whereA and B are each, independently of one another, an element of group IIIA, IVA, VA, IIIB, IVB, VB, VIB or VIIB of the Periodic Table of the Elements (Mendeleev),C represents an element of the 2nd period of the Periodic Table of the Elements (Mendeleev),x is a number from 1 to 3,y is a number from 0 to 3 andz is a number from 1 to 12.
摘要:
In a new process for the production of aromatic carbonates from aromatic hydroxy compound, CO and O.sub.2 in contact with a platinum-group metal catalyst, a co-catalyst, a quaternary salt and a base at elevated temperature and elevated pressure, an improvement is achieved if the reaction water is removed continuously from a partial flow of the reaction under reduced pressure and largely isothermal conditions and the dehydrated partial flow is again supplied to the reaction.