Hansen solubility parameters and thermodynamic modeling for LLE description during glycerol-settling in ester production from coconut oil

Abstract

The liquid-liquid equilibrium behavior is important when describing the separation of components involved in alkyl ester production during the glycerol-settling step. Therefore, this study presents original data on a liquid-liquid equilibrium system composed of glycerol + ethanol + ethyl esters from coconut oil at 298 K using an untapped approach based on the Hansen solubility parameters describing the individual ethyl ester distribution between the glycerol and ester rich phases. The difference in average molar masses of the ester mixtures in both phases when compared to fatty acid alkyl ester in overall composition reaches more than 10% depending on the ethanol content in the overall composition. The individual partition of ethyl esters in the glycerol-rich phase increases as result of the decrease in molecular size of this class of components. This behavior was shown based on the smaller difference in Hansen solubility parameters among esters with less carbon and the glycerol-rich phases as compared to esters with longer carbon chain atoms. Deviations between the experimental and calculated mass fractions were 0.83%, 4.07%, and 0.87% when using NRTL, UNIFAC-LLE, and UNIFAC-OHgly241725732CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIGFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP420355/2016-2; 308924/2017-7não temTEC-APQ-01412-1608/56258-8The authors thank the following funding agencies: Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) for its financial support (Process: TEC-APQ-01412-16) and for the master’s degree scholarship of Vanessa Vilela Lemos; the Conselho Nacional de Desenvolvimento Científico e Tecnológio (CNPq) for its financial support (Process: 420355/2016-2 and Process: 308924/2017-7); the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) for its financial support (Finance Code 001); the Fundação de Amparo a Pesquisa do Estado de São Paulo (Process: 08/56258-8) for its financial support; and the Partnerships Program for Education and Training (PAEC, Process: 001/2016) between the Organization of American States (OEA) and the Coimbra Group of Brazilian Universities (GCUB) for the master’s degree scholarship of Otto Alberto Quispe Jimene