Study On The Esterification Of Disproportionated Rosin And Glycerol

In this paper, the esterification of disproportionated rosin (DR) and glycerol was studied. Factors affecting the esterification including species of catalyst, the materials ratio, the amounts of catalyst, reaction temperature, reaction time, stirring rate and protective gas were investigated by the single-variable experiment. The result shows that the materials ratio, the amounts of catalyst, reaction temperature and reaction time are the main influencing factors with the optimum conditions of ZnO as the catalyst, CO2 as the protective gas and stirring rate 400r/min. By uniform design method, the optimal reaction conditions have been determined as follows: materials ratio of disproportionated rosin to glycerol was 2.5283:1.0000, the amounts of catalyst was 2.5029%。, reaction temperature was 280°C, reaction time was 2.8154h. The apparent kinetics of catalytic esterification of disproportionated rosin and glycerol on ZnO catalyst was discussed at temperature 250°C to 280°C. Based on the relationship between the acid value of product and time, the kinetic parameters of the system in different temperature were gained by the regression of EVIEWS software. In the scope of temperature the esterification can be regarded as the first order reaction approximatively. The A and Ea in Arrhenius equation were also determined, which are 2.21 × 106h-1 and 70.412KJ .mol-1 respectively. So the rate constants of the reaction is k = 2.21×106exp(-8469.1/T).The analytical methods of product were improved. Green solvent for determining the acid value of rosin glyceride by means of titration was studied. After the toxicity and volatility of six kinds of solvents were compared, turpentine was selected as a green solvent. The best mutualsolubility is given out when the proportion is 1.0 to 2.5. By means of the turpentine-ethanol solvent in the proportion of 1.0:2.5 and the benzene-ethanol solvent in the proportion of 2.0:1.0 used in the national standard GB10287-88, respectively, the errors of the acid values were compared and the correction equation established by the linear regression analysis is Y=1.0022X-0.4264 which makes the biggest relative error of the acid value less than 2.2%. Besides, electric stirrer was used in acid value titration and electric stirrer was used in the measurement of softening point, which increase the stirring efficiency and veracity of reading.