| 摘要 |
<p>PROCESS FOR THE PREPARATION OF DIPHENYLMETHANE DICARBAMATES AND POLYMETHYLENE POLYPHENYL CARBAMATES . Diphenylmethane dicarbamates and polymethylene polyphenyl carbamate homologs and derivatives of these compounds are produced by the condensation of N-aryl carbamic acid esters, such as ethylphenylcarbamate, with formaldehyde, para-formaldehyde or trioxane in the presence of an organic sulfonic or halogenated organic sulfonic acid which has an acid concentration of at least 75 per cent, at temperatures of from ambient to about 170.degree.C. and optionally in the presence of an inert solvent.</p> |
