Process intensification for the production of the ethyl esters of volatile fatty acids using aluminium chloride hexahydrate as a catalyst

TL;DR

This paper presents a novel process for producing ethyl esters of volatile fatty acids using aluminium chloride hexahydrate as a catalyst, achieving efficient reaction, phase separation, and energy savings, with potential environmental benefits.

Contribution

It introduces a new catalytic process with phase separation for ethyl ester production, optimized operational conditions, and a comparative economic and environmental analysis.

Findings

Achieves >99% ethyl ester in upper phase within 4 hours at 343 K.

Reduces energy requirements by more than 50% compared to traditional methods.

Potentially a zero waste, cleaner production process.

Abstract

A new process for obtaining the ethyl esters of volatile fatty acids with ethanol by using aluminium chloride hexahydrate as a catalyst is proposed. Aluminium chloride not only exhibits good activity, composition equilibrium is achieved within 4 hours at 343 K, but also induces a phase separation with a convenient distribution of the components. In fact, more than 99 %wt of the ethyl esters, together with most of the unreacted acid and ethanol, were found in the upper layer, which was well separated from the bottom phase, which contained the coformed water and over 97.8 %wt of the catalyst. The intensification of this reaction and separation was thoroughly investigated and the operational conditions optimised. The effects of this separation on the purification of the final ethyl esters is fully investigated. A new configuration of unit operations is designed for the specific production of ethyl acetate, simulated through Aspen Plus V9 and compared with the current industrial process based on sulfuric acid catalysis. The overall production and purification of ethyl acetate is economically competitive, reduces the energy requirements by more than 50 %, and is potentially a zero waste process, resulting in cleaner production.