The removal of dinitrochlorobenzene from industrial residuals by liquid-liquid extraction with chemical reaction

Nitrochlorobenzenes (NCBs) are very important in the chemical industry since they have been used as raw material for the manufacture of crop protection products, as active ingredients in the pharmaceutical industry, as pigments and as antioxidants as well as for other uses. In industrial processes, NCBs are produced by monochlorobenzene (MCB) nitration reactions and one of the main residuals formed is dinitrochlorobenzene (DNCB), which is mainly composed of the isomer 2,4DNCB. This subproduct, although of commercial interest when in its pure state, is generally incinerated due to the high costs of recovery treatment and purification. The objective of this study is to present an alternative to the treatment of industrial residuals containing DNCB. The technique consists of converting DNCB into sodium dinitrophenolate, which is very soluble in water and is also easy to reuse. For this purpose, liquid-liquid extraction with chemical reaction (alkaline hydrolysis) with a rotating disc contactor (RDC) is used. Experimental data on MCB nitration reactions as well as alkaline hydrolysis using a rotating disc contactor are presented.