- Processes for producing aromatic polycarbonate oligomer and aromatic polycarbonate
-
A process for producing continuously an aromatic polycarbonate oligomer by reacting an aromatic dihydroxy compound and an alkali metal base or an alkaline earth metal base with a carbonyl halide compound comprises: (1) feeding continuously to a tank reactor an aromatic dihydroxy compound, water, a molecular weight controlling agent, a polymerization catalyst, a carbonyl halide compound, and an organic solvent, and an alkali metal base or an alkaline earth metal base in an amount of 1.15-1.6 equivalents based on the aromatic dihydroxy compound, (2) carrying out the reaction with a residence time as defined by the following formula, where X is an amount of the polymerization catalyst in terms of mole % based on the amount of mole of the aromatic dihydroxy compound fed per unit time, and Y is a residence time (min.), and (3) continuously withdrawing the reaction mixture from the tank reactor to obtain an aromatic polycarbonate oligomer having a number average molecular weight of 1,000-10,000. An aromatic polycarbonate is produced by polycondensation of the aromatic polycarbonate oligomer.
- -
-
-
- Method for preparing aromatic bischloroformate compositions
-
Bischloroformate oligomer compositions are prepared by passing phosgene into a heterogeneous aqueous-organic mixture containing at least one dihydroxyaromatic compound, with simultaneous introduction of a base at a rate to maintain a specific pH range and to produce a specific volume ratio of aqueous to organic phase. By this method, it is possible to employ a minimum amount of phosgene. The reaction may be conducted batchwise or continuously. The bischloroformate composition may be employed for the preparation of cyclic polycarbonate oligomers or linear polycarbonate, and linear polycarbonate formation may be integrated with bischloroformate composition formation in a batch or continuous process.
- -
-
-
- Hydrogen Bonding. Part 18. Gas-Liquid Chromatographic Measurements for the Design and Selection of some Hydrogen Bond Acidic Phases Suitable for Use as Coatings on Piezoelectric Sorption Detectors
-
A number of involatile liquids based on 4,4'-isopropylidenediphenol (bisphenol-A) or other bisphenols have been prepared as candidate coatings for piezoelectric sorption detectors.The liquids have been used as GLC stationary phases, and gas-liquid partition coefficients of a series of solutes have been obtained for these phases.Application of the linear solvation energy equation below has revealed that two particular liquids (8 and 9) possess very large hydrogen bond acidities coupled to rather small hydrogen bond basicities, and hence might be suitable as coatings with selectivity towards solutes that are hydrogen bond bases.One other compound (10) is not suitable as a coating because it is a solid at room temperature, but it has very considerable hydrogen bond acidity, and may be suitable as a novel GLC stationary phase.In the linear solution energy equation above, K is the gas-liquid partition coefficient for a series of solutes on a given phase, and the explanatory variables R2, ?H2, αH2, βH2 and log L16 are solute parameters that we have described before.A term by term analysis of the equation can be used to evaluate quantitatively how specific solute-solvent interactions influence the magnitude of the various log K values.
- Abraham, Michael H.,Hamerton, Ian,Rose, John B.,Grate, Jay W.
-
p. 1417 - 1423
(2007/10/02)
-
- Bischoloroformate preparation method with phosgene removal and monochloroformate conversion
-
Aqueous bischloroformates are prepared by the reaction of a dihydroxyaromatic compound (e.g., bisphenol A) with phosgene in a substantially inert organic liquid (e.g., methylene chloride) and in the presence of an aqueous alkali metal or alkaline earth metal base, at a pH below about 8. After all solid dihydroxyaromatic compound has been consumed, the pH is raised to a higher value in the range of about 7-12, preferably 9-11, and maintained in said range until a major proportion of the unreacted phosgene has been hydrolyzed. At the same time, any monochloroformate in the product may be converted to bischloroformate.
- -
-
-
- Cyclic monocarbonate bishaloformates
-
Cyclic monocarbonate bischloroformates are prepared by the reaction of a carbonyl halide such as phosgene with a bridged substituted resorcinol or hydroquinone such as bis(2,4-dihydroxy-3-methylphenyl)methane or bis(2,5-dihydroxy-3,4,6-trimethylphenyl)methane in the presence of aqueous alkali metal hydroxide. The cyclic monocarbonate bischloroformates may be used for the preparation of linear or cyclic polycarbonates containing cyclic carbonate structural units, which may in turn be converted to crosslinked polycarbonates.
- -
-
-
- Polyetherimide bisphenol compositions
-
Polyetherimide bisphenols and bischloroformates are prepared by the reaction of dianhydrides or certain bisimides with aminophenols or mixtures thereof with diamines. They are useful as intermediates for the preparation of cyclic heterocarbonates, which may in turn be converted to linear copolycarbonates. The bisphenols can also be converted to salts which react with cyclic polycarbonate oligomers to form block copolyetherimidecarbonates.
- -
-
-