Nitrobenzene Coupling

Event Center BC

Azobenzene is a coupling product of nitrobenzene with DMSO, ethylene glycol, and KOH as reagents. Product samples were neutralized with 5% HCl and the organic extract was analyzed using GCMS. It is the purpose of these research groups to find greener ways to synthesize this product under several conditions while developing a practical mechanism. One part of the research focused on observing the products generated from a similar molecule, 2-Nitrotoluene. The reaction temperature was varied to determine the best conditions for this coupling. The other part of the research performed four different procedures; first, kinetic data was obtained for the reaction, the next experiment used either 100% DMSO or 100% ethylene glycol as a solvent. Next, a smaller scale reaction was run using mixed solvents with either TEMPO, a radical inhibitor or with 1,4-ditertbutylbenzene a potential internal standard. The last reaction was performed with 1 DMSO: 1 ethylene glycol ratio along with TEMPO and 1,4-ditertbutylbenzene. After these experiments; it was found that 2-Nitrotoluene as the reactant generates an azoarene product predominantly at 130° Celsius, but the intermediate azoxybenzene was formed in greatest amounts at 120° Celsius. The findings of the latter group show that azobenzene gradually increased throughout the heating process when 100% of DMSO was used; while azoxybezene increased initially, then decreased. In 100% ethylene glycol, the percent azobenzene fluctuated throughout the time points as did the azobenzene. In this procedure, TEMPO acted as a radical inhibitor changing the reaction pathway.