Phase Transitions in the catalyst-free synthesis of monoglycerides using near critical alcohols

COTABARREN, NATALIA S.; HEGEL, PABLO E.; PEREDA, SELVA

Carlos Paz

Conferencia; XI Iberoamerican conference on properties and phase equilibria for process design; 2018

Universidad Nacional de Córdoba

Mono/diglycerides (ACs) are oleochemical products derived from vegetable oils that are useful in different industries because of its emulsifying properties. They are used in the elaboration of food products, in the cosmetic and cleaning industry, and for the elaboration of medicinal products because of its antiviral and antibacterial properties [1,2]. These products are conventionally obtained by glycerolysis of triglycerides (TG) under high reaction temperatures (230 °C) in the presence of an alkaline catalyst. Special ACs can also be obtained from the direct glycerolysis of fatty acid esteres (FAE) with catalysts [3] or using supercritical alcohols [4]. Particularly, the catalyst-free reaction pathway from FAE seems highly promising regarding the production of special ACs due to the higher relative volatility that exhibit FAE with respect toACs. Moreover, studies reported in the last years [4,5] show that emerging technologies, such as the supercritical CO2 extraction, can be used to fractionate FAE and purify ACs at mild temperatures (40 °C) and moderated pressures (110 bar), avoiding thermal degradation.To enhance mass transfer and obtain high reaction rates it is essential to operate the reactor under an homogeneous phase. FAE and glycerol (GL) exhibit partial liquid miscibility even at very high temperatures, while FAE and short chain alcohols (methanol or ethanol) are miscible. Thus, the addition of alcohol promotes a homogeneous phase behavior[6,7]. In this work, we evaluate the phase behavior of the reactive system GL+FAE at at different temperatures and compositions using ethanol as co-solvent to asses feasible operating conditions for the glycerolysis of fatty acid ethyl esters.