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%.
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.
Method for preparing low-chlorinated impurity content isocyanate based on salt formation light gasification (by machine translation)
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Paragraph 0066-0067; 0080-0081, (2020/10/14)
The invention provides a method for preparing low-chlorinated impurity content isocyanate based on a salt-formation light gasification method. The proportion of the salt particle size distribution obtained by the salt formation reaction in the average particle size ±30% range is 70% or more, the average residence time without stirring is less than 60 min, and the product obtained by the method has lower chlorinated impurity content. (by machine translation)
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%.
Preferred Binding of Carboxylates by Chiral Urea Derivatives Containing α-Phenylethyl Group
Cortés-Hernández, Mayra,Rojas-Lima, Susana,Hernández-Rodríguez, Marcos,Cruz-Borbolla, Julián,López-Ruiz, Heraclio
, p. 416 - 424 (2016/07/06)
An efficient, simple protocol for the synthesis of a new family of chiral ureas 1 – 4 is described. The binding properties of 1 – 4 toward different anion (acetate, benzoate, fluoride, and chloride) have been studied by1H-NMR titration and have been observed in the case of 4 is a selective receptor for acetate. The theoretical calculation M06/6-311+G(d,p) helped us explain the binding properties observed. The most interesting observation is that this calculated structure is consistent with expected, based on the concept of allylic 1,3-strain (A1,3strain). When chiral caboxylates were studied, urea 1 was the best in discriminating between enantiomers.
Chemical determination of the absolute structures of resveratrol dimers, ampelopsins A, B, D and F
Takaya, Yoshiaki,Yan, Ke-Xu,Terashima, Kenji,Ito, Junko,Niwa, Masatake
, p. 7259 - 7265 (2007/10/03)
The absolute configurations of four stilbenedimers, (+)-ampelopsins A, (+)-ampelopsins B, (-)-ampelopsins D and (+)-ampelopsins F were respectively determined on the basis of chemical evidence.
Synthesis of isocyanates from carbamate esters employing boron trichloride
Butler,Alper
, p. 2575 - 2576 (2007/10/03)
The conversion of carbamate esters to isocyanates and diisocyanates of industrial importance is possible using BCl3 in the presence of Et3N; the reaction is simple in execution and work-up, occurring under mild conditions and affording isocyanates in excellent yields.
Amid group-containing diisocyanates and amide group-containing epoxy resins
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, (2008/06/13)
An amide group-containing epoxy resin obtained by reacting an epoxy resin with an amide group-containing diisocyanate obtained by reacting a diisocyanate with a dicarboxylic acid gives a uniform cured article showing high adhesiveness and is usable as an adhesive, a coating composition, and the like.
