Sustainable synthesis of 2-ethyl hexyl oleate via lipase-catalyzed esterification: A holistic simulation and cost analysis study

Abstract

Lipase catalyzed synthesis of fatty acid esters has recently attracted much attention as it represents a cleaner production route compared to the conventional energy intensive chemical method. In this study, the technical and economic viability of 2-ethyl hexyl oleate (2-EHO) synthesis by the catalytic esterification of oleic acid (OA) and 2-ethyl hexyl alcohol (2-EHA) in a stirred tank reactor using Novozym 435 (Candida antarctica lipase B) was investigated. A conversion rate of 91% was obtained by adopting the subsequent optimized parameters: 4% enzyme amount, 2 h reaction time, 4:1 M ratio of alcohol to fatty acid, 150 rpm stirring speed, and 60 °C temperature. The lipase operational stability study showed that enzymes can be used for 30 successive cycles without significant lose in activity. The use of Aspen Plus simulator enabled the development of a detailed process flow diagram, which significantly improved the understanding of this clean production method and assessed the overall costs. A holistic cost analysis revealed a production cost of $2109 per ton of 2-EHO, thereby yielding an approximate 28% profit margin relative to prevailing market rates. Rigorous financial assessments corroborated the project's viability, substantiating a net present value (NPV) of $14.7 MM, a return on investment (ROI) of 583.91% (plant life time = 15 years), projected Payback Period stands at 6 years, and an internal rate of return (IRR) of 23%. These results confirm the technical and economic feasibility of lipase catalyzed production of 2-EHO, highlighting its potential as an environmentally and profitable approach in the synthesis of fatty acid esters.