Reactive extraction of cis,cis-muconic acid from aqueous solution using phosphorus-bonded extractants, tri-n-octylphosphineoxide and tri-n-butyl phosphate: Equilibrium and thermodynamic study

Abstract

cis,cis-Muconic acid falls under the category of carboxylic acids and finds application mostly in biodegradable polymers, agrochemicals, and the food industry. Owing to the high thermal reactivity based upon the twoterminal carboxylic groups present in their structure, the chemical industry has widely used carboxylic acids. The major obstacle encountered during the production of carboxylic acids is their recovery from aqueous solutions and fermentation media. Therefore, the recovery of HccMA by reactive extraction as a particular product capture method, using tri-n-octylphosphine oxide (TOPO) and tri-n-butyl phosphate (TBP) in organic diluents such as 1-butanol, isoamyl alcohol, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), diisobutyl ketone, isobutanol, n-hexane, dimethyl glutarate, ethyl propionate, and diethyl carbonate (DEC) was executed in this study. This method was experimentally conducted to explore the most proper extractant and diluent combination. Extraction experiments were also conducted with pure diluents alone to examine the extractant effect on the extraction system. The important extraction parameters like distribution coefficient (KD), extraction efficiency (E %), loading ratio (Z), dimerization constant (D), partition coefficient (P), and complexation constant (KE11) were determined. Mass action law model interpreted the obtained results. For HccMA/TOPO extraction system, the maximum extraction efficiency was found 93.19% in the presence of n-hexane as a diluent. For HccMA/TBP extraction system, the maximum extraction efficiency was found 90.37% in the presence of ethyl propionate as a diluent. Thermodynamic studies at variable temperatures were also carried out to estimate Delta H, Delta S, and Delta G of the process. To investigate the feasibility of designing a counter-current liquid-liquid extraction column, the number of theoretical stages (NTS) were assessed by theodified Kremser equation and found between 3 and 5 to et the desired extraction efficiency.