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Deciphering Intermediates and Additives Effect on the Reduction of Nitrobenzene by SmI 2
Author(s) -
Surasani Seshi Reddy,
Maity Sandeepan
Publication year - 2017
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201601483
Subject(s) - aniline , nitrosobenzene , nitrobenzene , chemistry , benzaldehyde , imine , yield (engineering) , quantum yield , photochemistry , medicinal chemistry , organic chemistry , catalysis , materials science , metallurgy , physics , quantum mechanics , fluorescence
Product distribution in the reaction of nitrobenzene (NB) with SmI 2 shows a strong dependence on the number of equivalents of SmI 2 used. Phenylhydroxylamine (PHA), azoxybenzene (AZOB) and azobenzene (AZB) are the main products when the number of equivalents of SmI 2 is up to 4 equivalents. When 6 equivalents are used, aniline (AN) yield is higher and with 8 equivalents, the yield of aniline is 95 %. Using various techniques including chemical labelling, it was shown that none of the above compounds is an intermediate on the path of nitrobenzene to aniline. The suggested mechanism involves the formation of nitrosobenzene which is converted to an intermediate that could generate phenylhydroxylamine. Yet, in the presence of a large amount of SmI 2 it is converted directly to aniline, circumventing the production of phenylhydroxylamine. The ratio of aniline production to the condensed products (AZOB and AZB) was shown to be inversely proportional to the ability of the additives used to coordinate to SmI 2 . The observed order was: MeOH>Water>ethylene glycol>HMPA. Trapping of proposed intermediate with benzaldehyde gives synthetically useful products such as nitrone and Imine.