104-49-4Relevant articles and documents
Isocyanates From Primary Amines and Carbon Dioxide: 'Dehydration' of Carbamate Anions
Waldman, Thomas E.,McGhee, William D.
, p. 957 - 958 (1994)
Carbamate anions, derived from primary amines CO2 and an added base (e.g.NEt3), undergo rapid reaction with electrophilic 'dehydrating agents' (e.g.POCl3, P4O10) to give the corresponding isocyanates in excellent yields.
FLOW CHEMISTRY SYNTHESIS OF ISOCYANATES
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Paragraph 0175; 0185-0187; 0228; 0234-0239, (2021/06/22)
The disclosure provides, inter alia, safe and environmentally-friendly methods, such as flow chemistry, to synthesize isocyanates, such as methylene diphenyl diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and tetramethylxylene diisocyanate.
Preparation method of p-phenyl diisocyanate
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Paragraph 0045-0056, (2020/10/20)
The invention provides a preparation method of p-phenylene diisocyanate. The preparation method comprises the following steps that: p-phenylenediamine is dissolved in a low-boiling-point solvent undernormal temperature to 65 DEG C, so that a p-phenylenediamine solution can be prepared; di-(trichloromethyl) carbonate is dissolved in a high-boiling-point solvent, so that a di-(trichloromethyl) carbonate solution can be prepared; the p-phenylenediamine solution and the di-(trichloromethyl) carbonate solution are mixed, the mixed solution is subject to a reaction; and after the mixed solution issubjected to three reaction stages of cold light (from the normal temperature to 40 DEG C), warm light (50-80 DEG C) and hot light (110-180 DEG C), the p-phenylene diisocyanate can be obtained. According to the method, the p-phenylenediamine and the di-(trichloromethyl) carbonate are respectively dissolved by adopting the two solvents with different boiling points, and therefore, reaction energy consumption is effectively reduced, the purity of the obtained p-phenylenediamine is up to 99% through the three reaction stages; and the yield of the p-phenylenediamine is up to 97.8%.