Optimization of chemoenzymatic Baeyer–Villiger oxidation of cyclohexanone to ε‐caprolactone using response surface methodology

Abstract

ε-Caprolactone (ε-CL) has attracted a great deal of attention and a high product concentration is of great significance for reducing production cost. The optimization of ε-CL synthesis through chemoenzymatic Baeyer-Villiger oxidation mediated by immobilized Trichosporon laibacchii lipase was studied using response surface methodology (RSM). The yield of ε-CL was 98.06% with about 1.2 M ε-CL concentration that has a substantial increase mainly due to both better stability of the cross-linked immobilized lipase used and the optimum reaction conditions in which the concentration of cyclohexanone was 1.22 M, the molar ratio of cyclohexanone:urea hydrogen peroxide (UHP) was 1:1.3, and the reaction temperature was 56.5 C. Based on our experimental results, it can be safely concluded that there are three reactions in this reaction system, not just two reactions, in which the third reaction is that the acetic acid formed reacts with UHP to form peracetic acid in situ catalyzed by the immobilized lipase. A quadratic polynomial model based on RSM experimental results was developed and the R 2 value of the equation is 0.9988, indicating that model can predict the experimental results with high precision. The experimental results also show that the molar ratio of cyclohexanone to UHP has very significant impact on the yield of ε-CL (p < .0006). K E Y W O R D SBaeyer-Villiger oxidation, caprolactone, response surface methodology, response surface optimization, Trichosporon laibacchi lipase

Chemoenzymatic Dynamic Kinetic Resolution Protocol with an Immobilized Oxovanadium as a Racemization Catalyst

“…For extending the applicability of this chemoenzymatic one-pot protocol, important factors of the L-V-MD DKR course were investigated, and the optimized experimental design was carried out using RSM to access the optimal reaction conditions with significantly reduced experimental workload. , Multiple factors may affect the L-V-MD DKR of 2 , such as the amounts of L-MR and V-D, reaction temperature, time, organic solvents, and the concentrations of 2 and vinyl acetate, which may all effect the conversion of 2 , the yield of (R)- 3 , the enantiomer excess of 3 , and selectivity (Sel) which is ((R)- 3+ (S)- 3 )/((R)- 3 +(S)- 3+ dimer), where dimer is the byproduct of reaction 4. To understand the impact of various factors on the DKR reaction, multiple single factor experiments were conducted for the experimental RSM design.…”

Unraveling the mechanism and kinetics of aerobic Baeyer–Villiger oxidation of cyclohexanone

“…Recent advances propose a one‐pot chemoenzymatic synthesis method, fostering safer reaction conditions. It uses immobilized Trichosporon laibacchii lipase to produce peracetic acid from hydrogen peroxide, which then oxidizes the ketone to lactone 3,4 . Still, this process is lacking for large‐scale application due to high cost and challenges in catalyst amplification.…”