Table 3: The comparison of existing and proposed practice.

Sr. no.Process stepsWater consumption in klEffluent generation in klRecovered by-product

Existing process: Reaction temperature was maintained to 70°C by the addition of ice and reaction time of 3.5  h (3 h for acetylation and 30 min for neutralization with soda ash); yield was 90%.

(1)AcetylationNil76
(2)Nitration225258
(3)Hydrolysis275280
(4)Neutralization10116

Total510729

Proposed process: Reaction temperature was 120°C, in reaction time of 3 1/2 h (3 h for acetylation and 30 min for distillation of excess acetic acid); yield was 95%.              

(1)Acetylation NilNilSpent acid (15%)
(2)Nitration75NilSodium acetate (15%)
(3)Hydrolysis125Nil
(4)Neutralization10116

Total210116