摘要:
Methods for purifying a p,p-bisphenol A generally include distilling a feed stream comprising p,p-BPA in a distillation column at a pressure less than or equal to 20 millibars. The distillation column separates the bisphenol feed stream to produce a light fraction, an intermediate fraction and a heavy fraction. The intermediate fraction comprising the purified bisphenol contains lesser impurities that the p,p-BPA in the feed stream. In one embodiment, the intermediate stream is recovered using a side-draw. The side-draw is located between a first zone and a third zone in the distillation column.
摘要:
A polyetherimide resin is described herein. The resin includes a structure of repeating units of the formula (I) wherein each aromatic ring in the structure can be substituted with at least one halogen atom, nitro group, cyano group, alkyl group, cycloalkyl group, or aryl group. Another embodiment relates to a method for preparing a polyetherimide polymer. The method includes the step of reacting metaphenylenediamine bis(4-nitrophthalimide) with a bisphenolic mixture of a salt of bisphenol A and a salt of an arylcyano-modified bisphenol.
摘要:
A monomer and polycarbonate resin are provided, as are methods of making the monomer. The resin may be used to provide a thin film that has a higher dielectric constant and higher glass transition temperature, and similar breakdown strength and similar dissipation factor to films prepared from polycarbonate resins not so modified. The thin films, in turn, may advantageously be used to form, wholly or in part, articles such as capacitors, sensors, batteries, flexible printed circuit boards, keyboard membranes, motor/transformer insulations, cable wrappings, industrial tapes, interior coverage materials, and the like. In particular, a capacitor comprising the polycarbonate resin is also provided.
摘要:
Catalytic materials including divalent palladium compounds, divalent cobalt compounds and bromide sources such as tetraalkylammonium and hexaalkylguanidinium bromides are removed from organic carbonylation reaction mixtures comprising said materials in combination with diaryl carbonate and hydroxyaromatic compound. The removal steps include extraction with an aqueous complexing solution for palladium, extraction with an aqueous non-basic and preferably ionic extractant for cobalt, and extraction with water to remove bromide source. These steps may be combined into an integrated process. Further steps of recycle of the palladium by reduction to elemental palladium and conversion to a catalytically active species, and conversion of cobalt to a catalytically active species, may be included in the integrated process.
摘要:
A method for regenerating deactivated sulfonated cation exchange catalysts comprises washing the deactivated catalyst with phenol-water mixtures comprising about 5-20 wt. % of water in phenol at a temperature of about 70-95° C.
摘要:
Hydroxyaromatic compounds such as phenol are converted to diaryl carbonates by reaction with oxygen and carbon monoxide in the presence of a catalyst package which comprises a Group VIIIB metal, preferably palladium, salt of at least one aliphatic .beta.-diketone such as 2,4-pentanedione. The catalyst package also preferably comprises an inorganic cocatalyst, an organic cocatalyst and a bromide or chloride, preferably bromide, source such as a hexaalkylguanidinium bromide. The use of the .beta.-diketone salt confers such advantages as long shelf life under normal storage conditions, high activity upon recycle and capability of carbonylation at relatively low temperatures.
摘要:
Hydroxyaromatic compounds such as phenol are converted to diaryl carbonates by reaction with oxygen and carbon monoxide in the presence of a catalyst package which typically comprises a group VIIIB metal or compound thereof, an inorganic cocatalyst, an organic cocatalyst and a hexaalkylguanidinium bromide or chloride, preferably bromide. The use of the hexaalkylguanidinium salt causes an increase in the yield of diaryl carbonate without a decrease in selectivity.
摘要:
Hydroxyaromatic compounds such as phenol are converted to diaryl carbonates by reaction with oxygen and carbon monoxide in the presence of a catalyst package and an added diluent free from active hydrogen. The preferred catalyst packages comprise a Group VIIIB metal or salt thereof, an inorganic cocatalyst, and organic cocatalysts and a bromide or chloride source. The amount of added diluent is an effective amount to improve selectivity to diaryl carbonate. Preferred diluents are diphenyl carbonate and N-methylpyrrolidone.
摘要:
Adducts of hydroxyaromatic compounds such as phenol and diaryl carbonates such as diphenyl carbonate are washed with a washing composition comprising a major proportion, typically about 90%, of the hydroxyaromatic compound and a minor proportion, typically about 10%, of the diaryl carbonate.
摘要:
A method for recovering substantially pure p,p-bisarylols from a mixture comprising the same by subjecting the mixture to vacuum distillation and melt crystallization in the absence of an adduct crystallization and the generation of a reaction recycle stream.