Scheme 1
Enzyme-catalyzed transesterification synthesis of citronellyl acetate.
Figure 1
Effect of different ionic liquids. Reaction conditions: citronellol, 100 mmol/L; molar ratio of vinyl acetate to citronellol, 3:1; lipase, 10 mg/mL; temperature, 40 °C; speed of agitation, 200 r/min; (■) [BMIM][NTF2] (1-Butyl-3-MethylImidazolium bis(trifluoromethylsulfonyl)imide), (●) [BMIM][OTF] ( 1-Butyl-3-methylimidazolium trifluoromethanesulfonate), (▲) [BMIM][BF4] (1-Butyl-3-methylimidazolium tetrafluoroborate), (◆) [BMIM][PF6] (1-Butyl-3-methylimidazolium tetrafluoroborate), (★) [EOEIM][PF6] (1- ethoxyethyl -3- methylimidazole hexafluoroborate), (×) [EOEIM][BF4] (1- ethoxyethyl -3- methylimidazole tetrafluoroborate).
Figure 2
Effect of different lipases. Reaction conditions: citronellol, 100 mmol/L; molar ratio of vinyl acetate to citronellol, 3:1; lipase, 10 mg/mL; temperature, 40 °C; speed of agitation, 200 r/min; (■) Pseudomonas fluorescens, (●) Aspergillus niger, (▲) Candida rugosa, (★) Rhizopus oryzae, (◆) Mucor javanicus, (×) Burkholderia cepacia.
Figure 3
Effect of molar ratio of vinyl acetate to citronellol. Reaction conditions: citronellol, 100 mmol/L; lipase, 10 mg/mL; temperature, 40 °C; speed of agitation, 200 r/min; (■) 1:1, (●) 2:1, (▲) 3:1, (◆) 4:1, (×) 5:1.
Figure 4
Effect of temperature. Reaction conditions: citronellol, 100 mmol/L; molar ratio of vinyl acetate to citronellol, 3:1; lipase, 10 mg/mL; speed of agitation, 200 r/min; (■) 20 °C, (●) 30 °C, (▲) 40 °C, (◆) 50 °C, (×)60 °C.
Figure 5
Effect of enzyme loading. Reaction conditions: citronellol, 100 mmol/L; molar ratio of vinyl acetate to citronellol, 3:1; temperature, 40 °C; speed of agitation, 200 r/min; (■) 2.5 mg/mL, (●) 5 mg/mL, (▲) 7.5 mg/mL, (◆) 10 mg/mL, (×) 12.5 mg/mL.
Figure 6
Effect of speed of agitation. Reaction conditions: citronellol, 100 mmol/L; molar ratio of vinyl acetate to citronellol, 3:1; lipase, 10 mg/mL; temperature, 40 °C; (■) 50 r/min, (◆) 100 r/min, (▲) 150 r/min, (×) 200 r/min, (★) 250 r/min.
Figure 7
Effect of concentration of substrate. Reaction conditions: molar ratio of vinyl acetate to citronellol, 3:1; lipase, 10 mg/mL; temperature, 40 °C; speed of agitation, 200 rpm; (■) 100 mmol/L, (●) 200 mmol/L, (▲) 300 mmol/L, (★) 400 mmol/L, (×) 500 mmol/L.
Figure 8
Lineweaver-Burk plot. Reaction conditions: molar ratio of vinyl acetate to citronellol, 3:1; lipase, 10 mg/mL; temperature, 40 °C; speed of agitation, 200 r/min.
Figure 9
Effect of concentration of product. Reaction conditions: citronellol, 100 mmol/L; molar ratio of vinyl acetate to citronellol, 3:1; lipase, 10 mg/mL; temperature, 40 °C; speed of agitation, 200 rpm; (■) 0 mmol/L, (●) 50 mmol/L, (▲) 100 mmol/L, (◆) 150 mmol/L, (★) 200 mmol/L, (×) 250 mmol/L.
Figure 10
Effect of additional water. Reaction conditions: citronellol, 100 mmol/L; molar ratio of vinyl acetate to citronellol, 3:1; lipase, 10 mg/mL; temperature, 40 °C; speed of agitation, 200 rpm; (■) 0% (v/v), (●) 0.2% (v/v), (▲) 0.5% (v/v), (◆) 1% (v/v), (★) 2% (v/v), (×) 5% (v/v).
Figure 11
Reuseability of lipase. Reaction conditions: citronellol, 100 mmol/L; molar ratio of vinyl acetate to citronellol, 3:1; lipase, 10 mg/mL; temperature, 40 °C; speed of agitation, 200 r/min; reaction time, 6 h.
Figure 12
Lineweaver-Burk plot. Reaction conditions: lipase, 10 mg/mL; temperature, 40 °C; speed of agitation, 200 r/min; citronellol, (■) 100 mmol/L, (●) 300 mmol/L, (▲) 500 mmol/L.
Scheme 2
King-Altman scheme of the enzyme-catalyzed bi-bi transesterification.
Figure 13
Comparison of simulated values with the experimental data. For the initial concentration of citronellol, the experimental values are represented as points: (■) 100 mmol/L, (●) 200 mmol/L, (▲) 300 mmol/L, (★) 400 mmol/L, (×) 500 mmol/L. The simulated values are represented by the trend lines.