Publication: Isoamyl acetate production via miniaturized intensified reactor: a non-enzymatic and solvent free synthesis route
Date
2022-09-01
Authors
Yusoff Azudin, Nurhazwani
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Abstract
Process intensification refers to technologies that replaces large, expensive, energy-intensive equipment or processes with smaller, cheaper, efficient plants that combine multiple operations into one or fewer devices. This can be applied to isoamyl acetate production, which may provide positives value in economic, sustainability, and inherent safety factors within the overall process. Conventionally, this ester which has a characteristic of banana flavours were produced by extraction from its crops. Limitation in raw material and low yield making it unviable. Fischer esterification mechanism was introduced however consumers are concerned about environmental and health issues resulted from the procedure. Biotechnology route via enzymatic esterification seems to have high potential and industrially sensible however there is still room for improvement via process intensification. The production of isoamyl acetate was intensified by using a miniaturised intensified reactor (MIR) in a non enzymatic and solvent-free condition. Optimized reaction conditions between acetic anhydride and isoamyl alcohol in MIR was found to be at 80'C reaction temperature and 0.5 acid-alcohol molar ratio, with reaction rate constant equals to 1.3x10-4 L s-1
mol-1, 9.00x10-8 L s-1 mol-1 and -1.50x10-4 L s-1 mol-1for k1, k2 and k-2 respectively. Simulation of isoamyl acetate reaction was done via COMSOL Multiphysics ® with a grid independence study conducted giving an optimum mesh of 32.12x103 number of elements with 33s of computational period for 2-D analysis of this MIR study. The esterification reaction between acetic anhydride and isoamyl acetate that took place in this system was found to be a diffusion-controlled reaction. Simulation of reaction in a miniaturized intensified reactor was found to have a regression value of 0.9980 for isoamyl acetate concentration in comparison to the experimental value in the system. Optimization was done via adjustment of MIR by adding multi-inlet at three different locations and three different inlet flowrates. Adjusted MIR at inlet location-1 and location-2 with inlet velocity 1x10-5 m s-1 resulted in a conversion value equal to 0.97. similar as for the unmodified MIR. Inlet location-3 with inlet velocity 1x10-5 m s-1 has a conversion value of 0.96, whereas other inlet location at inlet velocity 2.5x10-5 m s-1and 7.00x10-5 m s-1 have conversion rate lower than the unmodified MIR. It was found that the increase in inlet number only increases a small amount of isoamyl acetate produced at the end of MIR, therefore the original unmodified MIR in this study is the best design with optimum isoamyl acetate production in a non-enzymatic and solvent-free system.