Ex Parte RICHTER et al - Page 15

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

               o-dichlorobenzene, and xylene (id., e.g., col. 3, ll. 1-6, and col. 4, l. 66, to            
               col. 5, l. 4).                                                                              
                      We find Bischof acknowledges that “[p]reparation of organic                          
               isocyanates by reacting amines with phosgene in the gas phase is known.                     
               (See, for example, Siefken, Justus Liebigs Ann. Chem. 562, 108 (1949)),”                    
               and that “such processes have, until now, been recommended only for the                     
               preparation of monoisocyanates . . . [,] commercially available                             
               (cyclo)aliphatic diisocyanates . . . or large-scale production of aromatic                  
               diisocyanates” (Bischof col. 1, ll. 10-18; emphasis supplied).  Thus, Bischof               
               would have disclosed to one of ordinary skill in the art the phosgenation of                
               aliphatic and cycloaliphatic diamines to the corresponding diisocyanates can                
               be conducted with an excess of phosgene in the vapor phase in continuous                    
               manner with an inert, diluent carrier gas at a temperature of from 200° to                  
               600° C and under pressure, with selective recovery of the diisocyanate                      
               followed by distillation to obtain the “pure” diisocyanate product in higher                
               yields than by conventional phosgenation processes (id., e.g., col. 1,                      
               ll. 48-56, col. 2, l. 1, to col. 3, l. 38, col. 4, ll. 12-50, and Examples 1-4).  The       
               selective recovery is conducted in inert solvent at a temperature above the                 
               decomposition temperature of the corresponding to the diisocyanate (id.,                    
               e.g., col. 4, ll. 12-35).  The solvents used for phosgenation and product                   
               recovery include chlorobenzene, o-dichlorobenzene, and xylene (id., e.g.,                   
               col. 3, ll. 25-28, and col. 4, ll. 24-30).                                                  
                      We find Joulak acknowledges that the preparation of mono- and                        
               polyisocyanates by phosgenation of amines “in the gaseous phase has long                    
               been known to this art, albeit such reaction has essentially been limited to                


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