摘要:
Polycarbonates are prepared in homogeneous solutions from dihydric phenols and phosgene wherein the stoichiometric end point for the addition of phosgene is accurately controlled by using 4-(p-nitrobenzyl) pyridine as a colorometric indicator for the end point in a series of samples of the reaction solution.
摘要:
A process for the preparation of phenol-phthalein wherein phenol and phthalic anhydride are reacted in the presence of a crosslinked sulfonic cation exchange resin in the acid form and wherein the water content of the reaction mixture is reduced by the use of aryl phosphites.The sulfonic cation exchange resin can be in the macroporous form or in the gel form. The range of useful crosslinking is 4-40 percent for the macroporous resin and 2-16 percent for the gel resin.
摘要:
Polycarbonates are heat stabilized by the incorporation of a dioxolane compound having a boiling point greater than about 250.degree. C. The amount of dioxolane compound used is from 100 to 10,000 parts per million.
摘要:
Thermoplastic polycarbonates are prepared by interfacial polymerization wherein carbonyl halides, dihydric phenols and a catalytic amount of a 1,1-dimethyl urea compound is reacted.The polycarbonates thus prepared are useful as moldable resins in a manner well known in the art.
摘要:
Symmetrical or 2,3,5,6-tetrahalopyridine is prepared from pentahalopyridine in an electrolytic cell by forming an organic solvent-free emulsion of pentahalopyridine and tetrahalopyridine and by electrolyzing the emulsion.
摘要:
The epihalohydrin yield in a process for preparing low molecular weight epoxy resins by coupling a polyhydric phenol and an epihalohydrin in the presence of an alkali metal hydroxide and subsequent dehydrohalogenation is improved by employing stoichiometric quantities of the alkali metal hydroxide with respect to the polyhydric phenol in the coupling reaction and also conducting the coupling reaction in the presence of a halohydrin that is at least as reactive as the halohydrin being formed.
摘要:
Catalysts for reacting vicinal epoxides with an aromatic hydroxyl-containing material result from the treatment of a solid substrate containing a plurality of ion-exchangeable cations with a polymer containing a multiplicity of quaternary onium cations in association with a reactive anion such that after treatment, there remains a sufficient quantity of the quaternary onium cations in association with the reactive anion to catalyze the reaction. These catalysts reduce the quantity of side reactions.
摘要:
Novel cyclic oligomers of the formula ##STR1## ARE PREPARED BY CONTACTING (A) A STRONG PROTIC ACID WITH (B) AN N-substituted non-activated aziridine of the formula ##STR2## wherein R.sub.1 and R.sub.2 are independently hydrogen or lower alkyl and R.sub.3 is hydrogen, hydroxyl, cyano or an organic radical which is inert in the process. The process is typically conducted in an aqueous alkanol medium. E.g. the cyclic tetramer of N-phenethylaziridine was obtained as the predominant product by heating a solution of N-phenethylaziridine in aqueous ethanol at reflux temperatures in the presence of p-toluenesulfonic acid.
摘要:
An electrically conductive polymer-latex composite is described. Organic polymeric material capable of being doped to provide an organic electroconductive material is dispersed in a latex and doped to provide an organic electroconductive polymer-latex composite.
摘要:
Catalysts for reacting vicinal epoxides with an aromatic hydroxyl-containing material result from the treatment of a solid substrate containing a plurality of ion-exchangeable cations with a polymer containing a multiplicity of quaternary onium cations in association with a reactive anion such that after treatment, there remains a sufficient quantity of the quaternary onium cations in association with the reactive anion to catalyze the reaction. These catalysts reduce the quantity of side reactions.