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.
Method for preparing p-phenylene diisocyanate by non-phosgene method
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, (2022/01/10)
The invention discloses a method for preparing p-phenylene diisocyanate by a non-phosgene method, one of the following methods is selected: (a) taking N, N''-(1, 4-phenylene) bis (N', N'-dialkyl) urea and protonic acid as raw materials, and carrying out protonation and pyrolysis to obtain p-phenylene diisocyanate; and (b) taking p-phenylenediamine, dialkyl carbamoyl chloride and an acid-binding agent as raw materials, carrying out nucleophilic substitution reaction to generate N, N''-(1, 4-phenylene) bis (N', N '-dialkyl) urea and ammonium hydrochloride corresponding to the acid-binding agent in situ, and then carrying out protonation and pyrolysis to obtain the p-phenylene diisocyanate. According to the preparation method, p-phenylene diisocyanate is synthesized in one step or continuously by using an intermittent tank reactor or a micro-channel continuous flow reactor under the action of protonic acid. The intermittent and continuous preparation process of the non-phosgene method has the advantages that the reaction time is short, the product is easy to separate, a hydrogen chloride byproduct is not generated and the like, the purity of the product is as high as 98%, and the yield is as high as 97%.
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%.