Equilibrium Study on Reactive Extraction of Nicotinic Acid from Aqueous Solution

Abstract

Nicotinic acid (3-pyridine carboxylic acid) widely used in food, pharmaceutical and biochemical industries is an important chemical. Due to ecological problems and complicate the synthesis methods, the chemical route for nicotinic acid production will become unattractive in the future. The aim of the present work is to study the reactive extraction of nicotinic acid from aqueous solutions using TOA dissolved in MIBK to intensify nicotinic acid production via enzymatic route. The extraction efficiency is determined in terms of distribution coefficient (KD), degrees of extraction (E) and loading ratios (Z). The effects of initial acid concentration and composition of extractant (TOA) are determined. The maximum value of KD is found to be 5.8 with TOA (0.57 mol/L) at an acid concentration of 0.12 mol/L. The mathematical model, based on mass action law, is proposed to estimate the values of equilibrium constants (KE) and number of reacting acid molecules per extractant molecules in chemical extraction. Population based search algorithm, differential evolution (DE) as an optimization algorithm is used to determine the equilibrium extraction constants (KE) and the stoichiometry of reactive extraction through a proposed equilibrium model. The model predicted values of KE are showing good correlation with R 2 > 0.98 and maximum value of SD = 0.092.