Kinetics of the 5-hydroxymethylfurfural formation reaction in Chinese rice wine

The kinetics of 5-hydroxymethylfurfural (HMF) formation in Chinese rice wine was investigated under different treatment conditions. Samples I and II were the rough rice wine and outflow fraction of the rice wine from the macroporous resin, respectively. Sample III was the fraction derived from sample II loaded through ion-exchange resin. The HMF content of the different samples under a range of temperature values from 323.15 to 363.15 K was measured by high-performance liquid chromatography. The results demonstrated that the kinetics of HMF formation in sample I was determined as first-order [C(t) = C(0) exp(kt)], but those for samples II and III were found to be the zero-order reaction [C(t) = C(0) + kt]. For all three samples, the relationships of reaction rates (k) and temperature (T) were computed as follows: k(1) = 2.81 x 10(5) exp(-43.01/RT), k(2) = 2.33 x 10(18) exp(-123.90/RT), and k(3) = 1.79 x 10(13) exp(-89.16/RT). By applying the Arrhenius equation k = k(f) exp(-E(a)/RT), the activation energy was 43.01, 123.90, and 89.16 kJ mol(-1), respectively. On the basis of these kinetics equations, weak polar components such as phenolic groups may be involved in HMF formation.