Method for making carbamates, ureas and isocyanates

Abstract

The present invention provides methods of forming carbamates, ureas, and isocyanates. In certain embodiments these methods include the step of reacting an amine with an ester-substituted diaryl carbonate to form an activated carbamate which can be further derivatized to form non-activated carbamate or a urea. The urea or carbamate can be subjected to a pyrolysis reaction to form isocyanate.

1 . A composition comprising a compound of the formula:
   X 1 —C(═O)—X 2  
   
       wherein X 1  is NR 1 R 2  and X 2  is NR 3 R 4  or OR 5 , and wherein
 R 1 , R 2 , and R 3  and R 4 , if present, are each independently selected from the group consisting of hydrogen, optionally-substituted linear or branched alkyl, alkene, cycloalkyl, cycloalkenyl, aryl, heteroatom-containing aryl, and aralkyl groups, or R 1  and R 2  in combination are a carbon atom double bonded to the nitrogen of X 1  or R 3  and R 4  in combination are a carbon atom double bonded to the nitrogen of X 2  or the N of X 1  or X 2  may be the nitrogen of a ring system, and 
 R 5 , if present, is selected from the group consisting of optionally-substituted linear or branched alkyl, aryl and aralkyl groups, or 
 R 1  or R 2  in combination with R 3 , R 4 , or R 5  form a five or six-member ring, and 
 the composition further comprises a detectable amount of residual ester-substituted diaryl carbonate or the corresponding ester-substituted phenol byproduct. 
 
     
     
         2 . The composition of  claim 1 , where the ester-substituted diaryl carbonate is bismethylsalicylcarbonate (BMSC) and the ester-substituted phenol byproduct is methyl salicylate. 
     
     
         3 . The composition of  claim 1 , wherein X 2  is NR 3 R 4 , whereby the compound is a urea. 
     
     
         4 . The composition of  claim 3 , wherein R 1  or R 2  in combination with R 3  or R 4  forms a five or six-member ring. 
     
     
         5 . The composition of  claim 1 , wherein X 2  is OR 5 , whereby the compound is a carbamate. 
     
     
         6 . The composition of  claim 5 , wherein R 1  or R 2  in combination with R 5  forms a five or six-member ring. 
     
     
         7 . A carbamate of the formula 
       
         
           
           
               
               
           
         
       
       wherein R 1 , and R 2  are each independently selected from the group consisting of hydrogen, optionally-substituted linear or branched alkyl, a heteroatom-containing alkyl, alkene, cycloalkyl, cycloalkenyl, aryl, heteroatom-containing aryl, heteroatom-containing aralkyl, and aralkyl groups, or R 1  and R 2  in combination are a carbon atom double bonded to the nitrogen or R 1  and R 2  are members of 5 or 6 membered ring, and
 R 3  is alkyl, aryl, or aralkyl. 
 
     
     
         8 . The carbamate of  claim 7 , wherein R 3  is methyl.