Ex Parte RICHTER et al - Page 14

               Appeal No. 2007-3827                                                                        
               Application 08/713,905                                                                      

               brief heating of the reaction product in vacuo below the boiling point of the               
               solvent used or by blowing a neutral gas through it at high temperature is                  
               sufficient for destroying or otherwise disposing of any carbamic acid                       
               chlorides still present” (id. col. 2, ll. 34-41).                                           
                      We find Biskup acknowledges that “[a]lthough the preparation of                      
               organic isocyanates from the corresponding amines by reaction with                          
               phosgene in the gas phase has long been known (e.g., Siefken, Ann. 562, 108                 
               (1949)), the process has, until now, only been of technical importance for                  
               monoamines . . . and (cyclo)aliphatic diamines” (Biskup col. 1,                             
               ll. 10-16; emphasis supplied).  Thus, Biskup would have disclosed to one of                 
               ordinary skill in the art that the phosgenation of aromatic diamines,                       
               including ether containing aromatic diamines, to the corresponding aromatic                 
               diisocyanates, including ether containing aromatic diisocyanates, in high                   
               yield can be conducted with an excess of phosgene in the vapor phase in                     
               continuous manner with an inert, diluent solvent carrier gas at a temperature               
               above the boiling point of the diamine with selective recovery and                          
               distillation of the diisocyanate at the same temperature, wherein the                       
               temperature is generally from 200° to 600°C and the process conducted                       
               under pressure (id., e.g., Abstract, col. 1, l. 45, to col., 2, l. 20, col. 2, l. 63, to    
               col. 3, l. 6, col. 3, l. 50, to col. 5, l. 4, col. 5, ll. 29-31, and Examples 1-3           
               and 5).  The selective recovery is conducted in inert solvent at a temperature              
               above the decomposition temperature of the carbamic acid chloride                           
               corresponding to the diisocyanate (id., e.g., col. 4, l. 50, to col. 5, l. 4).  The         
               solvents used for phosgenation and product recovery include chlorobenzene,                  



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