摘要:
Low-odor, storage-stable monomer-containing polyisocyanurate is prepared from isophorone diisocyanate by conducting a partial trimerization for 3 minutes to 3 hours in the presence of 0.05-2% by weight of a catalyst, based on the weight of the diisocyanate, the catalyst having the formula [R—NX3]m⊕mY⊖ wherein Y⊖ is a carboxylic acid anion of 4-8 carbons, R is a &bgr;-hydroxyalkyl group of 2-6 carbons, X is an alkylene group of 2-3 carbons and m is a number from 1.0 to 2.0. The three radicals X form a ring with the quaternary nitrogen by way of a common nitrogen atom, which may be partly &bgr;-hydroxyalkylated, said ring optionally having an OH group positioned &agr;, &bgr; or &ggr; to the nitrogen. The reaction proceeds at a temperature of 0-160° C.
摘要:
Cycloaliphatic diisocyanates can be prepared continuously and phosgene-free by reacting at least one cycloaliphatic diamine with at least one carbonic acid derivative and at least one alcohol to give a cycloaliphatic diurethane; freeing the cycloaliphatic diurethane of a low boiler, a medium boiler and mixtures thereof; thermally cleaving the cycloaliphatic diurethane in a cleavage apparatus to give a cycloaliphatic diisocyanate and a cleavage residue; continuously discharging a portion of the cleavage residue from the cleavage apparatus; removing the high boiler components from the discharge to obtain a purified discharge; reurethanizing the purified discharge with alcohol to obtain a reurethanized discharge; and recycling the reurethanized discharge into the process.
摘要:
Low chlorine, multi-staged method for producing cycloaliphatic diisocyanates. The invention relates to a multi-staged method for the continuous low-chlorine production of cycloaliphatic diisocyanates, comprising the synthesis of diaminodipheynl alkanes, the hydration thereof into the corresponding cycloaliphatic diamines and the subsequent conversion of cycloaliphatic diamines to the corresponding cycloalkylene biscarbamates and the thermal cleaving of the latter into the cycloaliphatic diisocyanates and alcohol.
摘要:
Low chlorine, multi-staged method for producing cycloaliphatic diisocyanates. The invention relates to a multi-staged method for the continuous low-chlorine production of cycloaliphatic diisocyanates, comprising the synthesis of diaminodipheynl alkanes, the hydration thereof into the corresponding cycloaliphatic diamines and the subsequent conversion of cycloaliphatic diamines to the corresponding cycloalkylene biscarbamates and the thermal cleaving of the latter into the cycloaliphatic diisocyanates and alcohol.
摘要:
The invention relates to a multi-stage process for the continuous, phosgene-free preparation of (cyclo)aliphatic diisocyanates that comprises the conversion of (cyclo)aliphatic diamines into the corresponding (cyclo)alkylene biscarbamates and the thermal cleaving of the latter into the (cyclo)alkylene diisocyanates and alcohol. The urea used in accordance with the invention and also the urea employed for the preparation of urea equivalents (e.g. alkyl carbonates, alkyl carbamates) as a possible precursor for the synthesis of the (cyclo)aliphatic biscarbamates is unconditioned.
摘要:
Cycloaliphatic diisocyanates can be prepared continuously and phosgene-free by reacting at least one cycloaliphatic diamine with at least one carbonic acid derivative and at least one alcohol to give a cycloaliphatic diurethane; freeing the cycloaliphatic diurethane of a low boiler, a medium boiler and mixtures thereof; thermally cleaving the cycloaliphatic diurethane in a cleavage apparatus to give a cycloaliphatic diisocyanate and a cleavage residue; continuously discharging a portion of the cleavage residue from the cleavage apparatus; removing the high boiler components from the discharge to obtain a purified discharge; reurethanizing the purified discharge with alcohol to obtain a reurethanized discharge; and recycling the reurethanized discharge into the process.