摘要:
A process for the production of light colored condensation resins, wherein phenols are reacted with .alpha.,.alpha.'-dihydroxy-diisopropyl benzenes in the presence of acids of phosphorus at temperatures of between 70.degree. and 270.degree.C.
摘要:
New cyclic carbonic acid derivatives of the formula ##STR1## in which R denotes either --CH.sub.2 OH, R.sup.1 then representing an alkyl radical having 1 to 4 C atoms, or ##STR2## R.sup.1 and R.sup.2 then independently of one another representing methyl or ethyl, or ##STR3## R.sup.1 and R.sup.3 then each representing an alkyl radical having 1 to 4 C atoms,or in whichR and R.sup.1 together denote ##STR4## wherein A represents the group ##STR5## or oxygen, a process for their preparation, and their use as copolymerization components in the preparation of polycarbonates.
摘要:
In a process for the preparation of dimethyl carbonate by reacting methanol with phosgene and/or methyl chloroformate, the improvement wherein the reaction is carried out in the presence of an aqueous alkali metal hydroxide solution and in the presence of an inert, water-immiscible organic solvent, at a temperature in the range from -20.degree. C. to +40.degree. C.
摘要:
A process for preparing a dialkyl carbonate by contacting a glycol carbonate with an alcohol at an elevated temperature in the presence of a thallium compound.
摘要:
An improved process for the preparation of a dialkyl carbonate by contacting a glycol carbonate with alcohol at an elevated temperature in the presence of an alkali metal or alkali metal compound, the improvement residing in employing less than 0.01 percent by weight of alkali metal and/or alkali metal compound, based upon the weight the reaction mixture.
摘要:
The present invention relates to a process for the preparation of polycarbonates which contain aliphatically bound hydroxyl groups by transesterification of aliphatic dihydroxy compounds with glycol carbonate, optionally in the presence of transesterification catalysts, with simultaneous separation of the glycol by fractional distillation, which process is characterized in that ethylene glycol is removed from the reaction mixture as an azeotropic mixture by means of inert solvents with which ethylene glycol is substantially immiscible. The present invention further relates to the preparation of polyurethanes from these polycarbonates.
摘要:
New cyclic carbonic acid derivatives of the formula ##STR1## in which R denotes either --CH.sub.2 OH, R.sup.1 then representing an alkyl radical having 1 to 4 C atoms, or ##STR2## R.sup.1 and R.sup.2 then independently of one another representing methyl or ethyl, or ##STR3## R.sup.1 and R.sup.5 then each representing an alkyl radical having 1 to 4 C atoms, or in whichR and R.sup.1 together denote ##STR4## wherein A represents the group ##STR5## or oxygen, a process for their preparation, and their use as copolymerization components in the preparation of polycarbonates.
摘要:
Anionic copolymers of lactams and aliphatic polycarbonates having urethane and carboxylic acid ester groups, preferably having recurring structural units of the formula:--NH--CO--O--Y--O--CO--(CR.sub.2).sub.n --whereinR represents hydrogen or C.sub.1 -C.sub.4 -alkyl;n represents an integer of from 2 to 13;Y represents the residue of an alcohol of the following formula:HO--X--OH,whereinX represents an open-chain, cyclic or mixed open-chain-cyclic alkylene radical having from 2 to 12 carbon atoms which is optionally substituted by C.sub.1 -C.sub.4 -alkyl and optionally interrupted by from 1 to 3 oxygen atoms, or a polyethylene glycol having a molecular weight up to 10,000 or an alkoxylation product of bifunctional phenols.
摘要:
The invention is directed to a process for the preparation of polycarbonates of Mw 20,000 to 180,000 by transesterification of diphenols and carbonic acid dialkyl esters in the presence of organo-tin-IV compounds and a monophenol.
摘要:
The present invention relates to an interfacial process for the production of polycarbonates having terminal, aliphatically bonded hydroxyl groups by reacting predominantly dihydric alcohols with phosgene or chlorocarbonic acid esters of predominantly dihydric alcohols and/or phenols using alkali liquors as HCl-binding agents and in the presence of inert solvents, the process according to the invention being distinguished by the fact that concentrated, aqueous alkali liquors are used as the HCl-binding agents and thiodiglycol, optionally mixed with additional monohydric and polyhydric alcohols, is used as the dihydric alcohol. The present invention further relates to the new polycarbonates produced according to the novel process and to the use of these new polycarbonates for the production of polyurethane plastics.