摘要:
The present invention relates to a process for the continuous preparation of diaryl carbonates from phosgene and at least one monohydroxy compound (monophenol) in the presence of catalysts, and also the use thereof for preparing polycarbonates. The hydrogen chloride formed in the reaction is converted by thermal oxidation into chlorine, with the chlorine being recirculated to the preparation of phosgene. In particular, the process comprises utilization of the hydrogen chloride formed for the process for preparing diphenyl carbonate (DPC process).
摘要:
The invention provides a process for the preparation of diaryl carbonates and/or alkylaryl carbonates from dialkyl carbonates and aromatic hydroxy compounds using one or more intermediate condensers for improving heat integration.
摘要:
The present invention relates to a process for the continuous preparation of polycarbonates or diaryl carbonates by the method of the phase boundary process, in which both the mixing of the organic and aqueous phase and the upstream oligomerization step or aryl chloroformate and/or diaryl carbonate preparation step are effected in a special pump.
摘要:
The invention relates to a combined process for the preparation of polycarbonate by the phase boundary process and downstream electrolysis of sodium chloride-containing process wastewater.
摘要:
The invention relates to a process for preparing diaryl carbonates by reacting monophenols with phosgene or aryl chlorocarbonates with elimination of hydrogen chloride in the presence of mixed hydroxides of elements from groups 2-14 of the periodic table (IUPAC, new) as heterogeneous catalysts.
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:
Processes comprising: (a) reacting phosgene and a monohydroxyl aryl compound in the presence of a suitable catalyst to form a diaryl carbonate and a solution comprising an alkali chloride; (b) separating the diaryl carbonate from the solution; (c) adjusting the pH of the solution to a value of less than or equal to 8 to form a pH-adjusted solution; (d) treating the pH-adjusted solution with an adsorbent to form a treated solution; (e) subjecting at least a portion of the treated solution to electrochemical oxidation to form chlorine and an alkali hydroxide solution; and (f) recycling at least a portion of one or both of the chlorine and the alkali hydroxide solution.
摘要:
Low-pressure, mercury vapor discharge lamp has at least two dual-shaped lamp parts (1; 2; 3), each comprising a first and a second tube (11,21,31; 12;22;32). The first and second tube are interconnected via tube interconnection means (10; 20; 30) at a first end portion (11a, 12a;21a, 22a;31a,32a). A discharge path is formed through the tubes between two electrodes (13; 33). Each electrode is provided at a second end portion (11b; 32b) of one of the tubes (11; 32). Further second end portions (12b; 21b; 22b; 31b)are provided with respective sealed ends (12c; 21c; 22c; 31c). Bridge parts (50; 60) for interconnecting tubes (12,21; 22,31) of mutually adjacent dual-shaped lamp parts (1,2; 2,3) are provided in the proximity of the second end portions (12b,21b; 22b,31b). At least one of the sealed ends (21c) is provided with an exhaust tube (71) which is directly provided on the respective sealed end.
摘要:
Disclosed herein is a process for the preparation of carboxylic acid benzyl esters from dibenzyl ethers, comprising reacting dibenzyl ethers with carboxylic acids in the presence of a homogeneous acidic catalyst.
摘要:
The invention relates to new substituted 1-arylpyrazoles of the general formula (I) to a plurality of processes for their preparation, and to their use as pesticides.