Title : Comparative simulation of isopropyl palmitate synthesis in a microreactor with static elements and a batch reactor
Abstract:
The personal care and beauty industry has significantly expanded in recent years. Within the variety of products encompassing skin, face, hair, and body care, oleochemicals stand out due to their animal or plant origin, which contributes to better sustainability compared to synthetic and petrochemical substances. One class of oleochemicals is fatty acid esters, which can be used as detergents, in cosmetics manufacturing, and in certain foods. Isopropyl palmitate (IPP) is an oleochemical with adsorption properties, widely used in the personal care industry as an emollient and as an excellent organic solvent. To produce IPP, a variety of reactors are available, with the batch reactor being one of the most conventional and widely used in chemical and biochemical processes. However, it has certain disadvantages, such as limitations in homogeneity, thermal challenges, high energy consumption, difficulties in scaling up, among others. In this context, one alternative is the use of microreactors, as they have demonstrated numerous advantages due to fluid flow occurring at micrometric dimensions. This enables several benefits, including reduced residence time, low reagent consumption, low manufacturing cost, high heat and mass transfer rates, and a high surface-area-to-volume ratio. In many cases, simulations are performed prior to reactions, contributing to the identification of experimental starting points and process optimizations. Within the various branches of simulations, their application in chemical reactions has gained increasing prominence, as it allows for achieving higher yields, reaction conversions, and product selectivity. Routes to produce isopropyl palmitate (IPP) generally involve the esterification of palmitic acid with isopropanol in the presence of biocatalysts and high temperatures. However, a non-catalytic route at lower temperatures has emerged as an alternative to biocatalytic pathways and utilizes the following reagents: palmitic acid (PA), thionyl chloride (TC), and isopropyl alcohol (IPA). Initially, PA and TC react through a nucleophilic attack, forming PC and hydrogen chloride (HCl). In the second step, an alcoholysis reaction occurs in which IPA reacts with PC, forming a tetrahedral intermediate, which yields IPP. Therefore, the aim of this study is a comparison between simulations performed in a batch reactor and a microreactor with static elements for the synthesis of isopropyl palmitate. The simulations utilized kinetic data from a previous study conducted by other authors. In both reactors, the same conditions were maintained: temperature of 65°C and pressure of 1 atm. The results show that the batch reactor required 80–90 minutes to achieve a 99% conversion. Conversely, in the microreactor with static elements, a residence time of only 50 seconds was sufficient to achieve the same conversion percentage. The results show the distribution of reagents throughout their volumes. Therefore, it has been demonstrated that the use of microreactors with static elements is advantageous, as they enhance reagent mixing, enabling the production of the target compound with high conversions in significantly shorter times, compared to traditional reactors, which are still widely used in industrial processes.
