Thermodynamic And Kinetic Studies On The Reaction Of Camphene With Isopropanol

As a bicyclic monoterpene, camphene, which has a smell of camphor, is important raw material of synthetic spices and pharmaceutical intermediates. A number of valuable isobornyl ethers as flavors and fragrances in perfume and cosmetic products can be produced by acid-catalyzed alkoxylation of camphene. Camphene reacted with isopropanol mainly generates isobornyl isopropyl ether, which has long-lasting, woody, dry amber and cedar scents and has valuably applicable in many fields.In this study, the effects of various parameters on the alkoxylation of camphene with isopropanol, such as solvent, initial molar ratio of reactants, agitation speed, catalyst type, reaction temperature and reusability of catalysts, were investigated in a 250 mL glass stirred tank reactor to optimize the reaction conditions. Besides, the optimized reaction conditions were also amplified in a 5 L double layer glass reaction kettle and a fixed bed reactor. Thermodynamic parameters and kinetic parameters were derived by correlating experimental data.Achievements obtained in this study are as follows:1. The optimum reaction conditions in the 250 mL glass stirred tank reactor: initial molar ratio of camphene to isopropanol was 1:5; Lewatit 2620 as catalyst; catalyst loading based on the total mass of reactants was 15%; agitation speed was 400 rpm; reaction temperature was 353.15 K. After 8-hour reaction under the optimized reaction conditions, the conversion of camphene was 66.9% and the selectivity of isobornyl isopropyl ether was 93.5%. Lewatit 2620 showed good catalytic activity after reusing for eight times.2. The optimized reaction conditions were also amplified in a 5 L double layer glass reaction kettle and a fixed bed reactor. From the perspective of conversion of camphene and selectivity of isobornyl isopropyl ether, result in the 5 L double layer glass reaction kettle is almost the same as the small-scale experiment; result in the fixed bed reactor with 5% catalyst loading is almost the same as the small-scale experiment with 15% catalyst loading.3. The UNIFAC group contribution method was used to calculate activity coefficients of reactants. The reaction equilibrium constant decreases with increasing temperature, indicating that the reaction of camphene with isopropanol is an exothermic process.The enthalpy, entropy and free energy changes were calculated by two different methods. When ΔrH0 was regarded as constant, the enthalpy, entropy and free energy changes were -35.741 kJ/mol、-93.125 J/(mol·K)、-7.989 kJ/mol. By considering ΔrH0 as a function of temperature, at 298.15 K,4. Both PH and ER models were introduced to fit experimental data in the stirred tank reactor. Excellent agreements were achieved between experimental results and calculated values, revealing that both the models can be used to describe the kinetics for the alkoxylation of camphene with isopropanol. PH model: Where: ER model:A Langmuir-Hinshelwood-Hougen-Watson (LHHW) model based on activity was introduced to fit experimental data in the fixed bed reactor for the purpose of deriving kinetic parameters. It was shown that the calculated results from the model were in excellent agreement with the experimental ones. LHHW model: Where:...