Method for synthesizing fluoroalkyl-substituted 4,4'-diaminodiphenylmethane compound

A method for synthesizing a fluoroalkyl-substituted 4,4′-diaminodiphenylmethane compound, comprising:

• under the action of a catalyst, allowing an aromatic primary amine compound to react with a difluoroacetaldehyde hydrate, a trifluoroacetaldehyde a 2,2,3,3-tetrafluoropropionaldehyde hydrate, a pentafluoropropionaldehyde hydrate, a heptafluorobutyraldehyde hydrate, or a nonafluorovaleraldehyde hydrate in an organic solvent, and after completion of the reaction, performing post-treatment to obtain the fluoroalkyl-substituted 4,4′-diaminodiphenylmethane compound having a structure of general formula [1]:
• wherein in the general formula [1], n1 and n2 are respectively and independently an integer of 0-4, and in cases where multiple R1 are present, respectively and independently represent a substituent;
• R1 is independently selected from hydrogen, alkyl, alkoxy, cycloalkyl, aryl, propenyl, halogen, hydroxyl, benzyl, and thioalkyl;
• Rf is independently selected from difluoromethyl, trifluoromethyl, tetrafluoroethyl, pentafluoroethyl, heptafluoropropyl, and nonafluorobutyl;
• X is independently selected from methylene, oxygen, or sulfur;
• the catalyst is a Lewis acid or Brønsted acid;
• the organic solvent is 2,2-difluoroethanol, hexafluoroisopropanol, hexafluoro-2-methylisopropanol, hexafluoro-2-phenylisopropanol, trifluoroethanol, perfluoroalkylethanol, perfluoro-tert-butanol, tetrafluoropropanol, tetrafluorobutanediol, hexafluorobutanol, or octafluoropentanol;
• and
• the post-treatment comprises:
• after completion of the reaction, removing the solvent under reduced pressure, and recrystallizing a crude reaction product to obtain the fluoroalkyl-substituted 4,4′-diaminodiphenylmethane compound;
• and after completion of the reaction, recovering a fluoroalcohol solvent through a simple distillation operation.