Study On The Synthesis Of 2, 6-Diisopropylphenyl-Carbodiimides

This paper is mainly about the synthesis of 2,6-diisopropylphenyl-carbodiimides. The 2,6-diisopropylphenyl-carbodiimides are preferable used as stabilizers against hydrolytic degradation and oxidation of polycondensation product, e.g. polyether esters, polyester amides and polyurethanes. As an important finechemical intermediate, it has also been used in the synthesis of biochemistry product, pharmacy and coloring matter.This paper summarized the mainly methods of preparation 2,6-diisopropylphenyl-carbodiimides and its relevant intermediates. For the objective of ?industrial preparation, designed the following synthesis path: using the 2,6-diisopropylphenyl-aniline and phosgene to produce the 2,6-diisopropylphenyl-isocyanate, and manufacturing carbodiimides by the condensation reaction of the corresponding isocyanate.In the process of preparation 2,6-diisopropylphenyl-isocyanate by phosgenation, the suitable concentration of the aniline is 16%, the time of thermal phosgenation is 2hr, the molar ratio of aniline to phosgenation is 1:3. When the solvent in distilled product is about 17.8%, the yield of distilled is up to 99%. The yield of the phosgenation reaction is about 97%.In the research of preparation carbodiimides by the condensation reaction of the aromatic isocyanate, choosing phenolate as the catalyzer, the suitable weight ratio of phenolate in isocyanate is about 4%. Using the high boiling-point solvent trichloride-benzene as the reaction's protecting solvent, the suitable weight ratio of solvent to isocyanate is about 1.2:1. For the improving the reaction's efficiency, introduced the method of staged temperature control to optimize the process of condensation reaction, which has achieved satisfied result. The yield of condensation reaction is 96%. The pure of 2,6-diisopropylphenyl-carbodiimides is about 97.3%.