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A facile synthesis of 2, 5‐diamino‐p‐benzoquinones (DABQs) is reported under very mild conditions by mere crystallization. Mechanistic studies by density functional theoretical (DFT) calculations revealed an oxidative C(sp2)‐C(sp2) bond cleavage reaction mechanism via a dioxetane intermediate, from enamine oxidation of a mixture of ethyl vanillin and primary amines by triplet molecular oxygen. A second air oxidation event in the sequence of the reaction that results in C(sp2)‐C(sp2) bond formation is also described by DFT studies. The mechanistic insights enabled synthesis of both symmetric and unsymmetric DABQs from primary amines with a broad substrate scope.

In recent years, extensive work is being conducted to improve the biodegradability index (BI) of effluent to enhance the efficiency of biochemical treatment. Advanced oxidation processes are one among the various methods used as primer to improve the BI of organic effluent. In the present investigation, experiments such as electrocoagulation, electro-oxidation and photochemical were carried out to treat pulp and paper wastewater in a wide range of operating conditions. The effect of individual parameters on BI improvement was critically examined. It was noticed that electro-oxidation method yields maximum biodegradability improvement (0.13-0.42) within process time of 35 min.

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