In the context of cellulose valorization, we studied the kinetics of levulinates synthesis via the solvolysis of 5-HMF by alcohol over Amberlite IR-120. The alcohol plays a double role; it is a reactant and acts as the solvent. In the literature, kinetic models were developed for each type of alcohol, but there were no models combining the dual effect of alcohol alkyl group substituent (ROH) as a reactant and solvent. Such global kinetic models can save time and optimize a process by considering the solvent effect. This effect was taken into account via the Kamlet–Abboud–Taft and Taft equations, using Bayesian inference. We studied the kinetics of levulinate production from 5-HMF in a reaction mixture made of alcohol and GVL within a temperature range from 80 to 115 °C. The following alcohols were used: methanol, ethanol, propanol, butanol, pentanol, and hexanol. It was found that the rate of alkyl levulinate production increases faster in alcohol reaction medium compared to water reaction medium, and increases when increasing the alkyl group substitution. Among the global kinetic models developed in this study, the one that neglects the side reaction of humins was found to be the most reliable.