The influence of temperature on reaction rate during the oleic acid esterification process with trimethylolpropane

The kinetics of the acid-catalyzed esterification of oleic acid with trimethylolpropane (monitored by analyzing the acid value of the aliquots taken from the mixture) was carried out under vacuum and studied at following temperatures: 90, 105, 120 and 150°C, using 1% of p-TSA as a catalyst and the duration time of 1200 min. The observed reaction rate of the process was the highest at a temperature of 150°C in comparison with the other studied reaction temperatures. In addition, when carrying out the reaction at 120°C and 150°C, the yields were almost the same, as shown by the close final acid values at 1200th minute, which were 2.71 mg KOH/g and 2.5 mg KOH/g respectively. But they were significantly lower than acid values observed at 90°C and 105°C, which were 5.66 mg KOH/g and 4.35 mg KOH/g respectively. However, as the temperature rises, the possibility of side reactions with the formation of undesired products increases. Therefore, based on the experiment, in order to select the optimal reaction conditions, the reaction temperature must be precisely selected by variations in the range between 105°C and 120°C. Further studies of the model reaction will be performed in order to select the optimal temperature and the optimal amount of p-TSA, which on the one hand effectively catalyzes the rapid course of the reaction and on the other hand does not cause other undesirable processes such as emulsification and darkening of the reaction mixture. The latter lead both - to difficulties in the purification of the final product and to the deterioration of its commercial qualities.