Hydrolysis of tri-butyl phosphate in n-dodecane using sodium hydroxide: Factors affecting the hydrolysis process

Abstract

Alkaline hydrolysis of tri-n-butyl phosphate (TBP) in n-dodecane (n-DD) using sodium hydroxide was studied for the treatment and disposal of spent organic waste generated from nuclear reprocessing plants. Experiments were performed in a stainless steel autoclave with a process volume of about 1 L to investigate the effect of agitator speed, temperature, organic to aqueous phase ratio, and concentration of sodium hydroxide on the kinetics of TBP hydrolysis. The concentration of TBP gradually decreased with increase in the duration of hydrolysis followed by a sharp fall in the concentration of TBP due to autocatalytic hydrolysis of TBP. The diluent does not take part in the hydrolysis reaction which was evident from the third phase formation during the course of hydrolysis. The present study confirms the complete conversion of TBP to its aqueous soluble products during hydrolysis. The results showed that among the various parameters studied, the concentration of NaOH and temperature were the key factors in determining the rate of hydrolysis of TBP. By using 12.5 M NaOH, aqueous phase to organic phase ratio above 1/3, temperature above 353 K, at an agitation speed of 1000 rpm, nearly complete hydrolysis of 1.1 M TBP was achieved in less than 3 h.