Production of 2-phenylethyl acetate via reactive distillation

Bioproduction of Natural Phenethyl Acetate, Phenylacetic Acid, Ethyl Phenylacetate, and Phenethyl Phenylacetate from Renewable Feedstock

Natural phenethyl acetate (PEA), phenylacetic acid (PAA), ethyl phenylacetate (Et-PA), and phenethyl phenylacetate (PE-PA) are highly desirable aroma chemicals, but with limited availability and high price. Here, green, sustainable, and efficient bioproduction of these chemicals as natural products from renewable feedstocks was developed. PEA and PAA were synthesized from l-phenylalanine (l-Phe) via novel six- and five-enzyme cascades, respectively. Whole-cell-based cascade biotransformation of 100 mm l-Phe in a two-phase system (aqueous/organic: 1 : 0.5 v/v) containing ethyl oleate or biodiesel as green solvent gave 13.6 g L^-1 PEA (83.1 % conv.) and 11.6 g L^-1 PAA (87.1 % conv.), respectively. Coupled fermentation and biotransformation approach produced 10.4 g L^-1 PEA and 9.2 g L^-1 PAA from glucose or glycerol, respectively. The biosynthesized PAA was converted to natural Et-PA and PE-PA by esterification using lipases with ethanol or 2-phenylethanol derived from sugar, affording 2.7 g L^-1 Et-PA (83.1 % conv.) and 4.6 g L^-1 PE-PA (96.3 % conv.), respectively.

Energy-saving investigation of vacuum reactive distillation for the production of ethyl acetate

Ethyl acetate (EtAc) reactive distillation (RD) configurations often use atmospheric pressure, and this operating pressure can be reduced further to conserve energy based on the condenser cooling water temperature. Using the Aspen Plus simulator, two proposed configurations, RD column with stripper and pressure swing reactive distillation (PSRD), were simulated at lower operating pressure. The impact of RD column operating pressure on total energy usage and total annual cost (TAC) was studied. All design parameters were optimized using sequential iterative optimization procedures and sensitivity analysis to minimize the energy cost while maintaining the required product purity at 99.99%. The simulation results showed that the RD column with a stripper is better than PSRD with a saving of 23.17% in TAC and 31.53% in the specific cost of EtAc per kg. Compared to literature results, the proposed configurations have lower reboiler duty requirements and lower cost per kg of EtAc.

Multi-Aspect Comparison of Ethyl Acetate Production Pathways: Reactive Distillation Process Integration and Intensification via Mechanical and Chemical Approach

This paper provides a multi-aspect comparison of selected methods of ethyl acetate production and shows the possibility of further reactive distillation process integration and sophisticated intensification including process stream regeneration. The production pathways were selected with respect to their practical applicability and sufficient experimental and feasibility studies already published. A total of four case studies were designed and compared: conventional process set-up (ethyl acetate is produced in a chemical reactor) is designed as a base case study; reactive distillation with a separation unit is derived from the conventional process set-up. The mechanical and chemical approach to reactive distillation process intensification and integration were assumed: reactive distillation column with a stripper and reactive distillation column with an auxiliary chemical reaction (ethylene oxide hydration). Process models were compiled in the Aspen Plus software. Complex process flowsheets of selected case studies including separation and regeneration were designed and optimized. Three different points of view were applied to evaluate the selected process benefits and drawbacks. Process energy, economy, and safety were assessed. As a result, a reactive distillation column with an auxiliary chemical reaction has been proven to be the most suitable pathway for ethyl acetate production assuming all three evaluated aspects.