| Quote: |
| Originally posted by leu One of Reppe's many innovations in acetylene chemistry was the development of a catalyst, dicarbonyldi(triphenylphosphino) nickel [(CO)2Ni(Ph3P)2] in the presence of which the trimerization of acetylenes to benzenes can be carried out smoothly and efficiently at temperatures of 60-70°. Thus acetylene gives benzene in high yield (80 per cent) while monosubstituted acetylenes furnish either 1 : 3 : 5- or 1 : 2 : 4-trisubstituted benzenes or mixtures of the two isomers, the exact reaction course depending on the nature of the initial acetylene. Use of the catalyst also enables the copolymerization of acetylene with a substituted ethylene in a 2 : 1 or 1 : 2 ratio with the production of cyclohexa-1:3-dienes and cyclohexenes respectively, Another novel Reppe process, hitherto little developed, entails the reaction of acetylene with iron carbonyl hydride, Fe(CO)4H2, in aqueous media, whereby hydroquinone is formed. This reaction has also been applied to mono- and di-substituted acetylenes, the former compounds yielding the 2 : 5-disubstituted hydroquinones; acetylenic hydrocarbons, ethers and amines have been successfully subjected to the procedure. Seven papers have been uploaded to the Organic Chemistry forum of Wet Dreams, three on the actual syntheses, and four on the catalysts [Edited on 4-7-2006 by leu] |
| Quote: |
