Isolation, Purification And Thermodynamic Study Of Levorotatory Pimaric Acid And Its Derivative

Levopimaric acid is one of the natural resin acid,has significant economic value and is valuable renewable resource.Its derivatives are widely used in the field of pesticides,spices,food and medicine,have broad domestic and international markets.Nowdays,rosin acid materials have development trend of fine chemicals.Directly use of pure primary levopimaric,and then to current international use of its derivatives as well as to the depth of the pure product,and finally the development of its proprietary series products,pesticides,food the potential for use in the pharmaceutical,that have magnificant and giant meaning in industry.Separation and purification of the resulting levopimaric acid from natural pine resin,the ring having a conjugated double bond with rosin acids,because of its high chemical activity,it is often used as a raw material involved in many of the typical reaction of resin,and that acid derivatives are widely used in coatings,pharmaceuticals,pesticides and spices,and other fields.Levopimaric acid’s separation and purification and then studying the thermodynamic properties and chemical reactions of turpentine,deep processing and utilization have great significance.This article researched on several aspects as follows.1.Use amination turpentine isolating levopimaric acid by single factor and orthogonal experiment from the optimum conditions.The conditions are as follows:Levopimaric acid in ethanol at a concentration of 100%,a crystallization temperature of 0℃,the amount of ethanol used in the crystallization volume ratio of 20:1(mL/g),and recrystallized is 2 times,levopimaric acid purity of 95%.2.Use the maximum amount of single crystal growing method was dissolved in ethanol at-8～4℃ crystallization.Recrystallized from ethanol as reagent,under conditions of single crystal ultrasound after crystallization twice recrystallized.Levopimaric acid purity was up to 97%.3.The use of group contribution method Benson method and Joback law,C-G method is in levopimaric acid and its derivatives thermodynamic calculation,Benson calculation method’s results were below:Levopimaric acid ΔHfθ=-700.86KJ/moL,ΔGfθ=-80KJ/moL;Acrylpimaric acid ΔHfθ=1137.02 KJ/moL,ΔGfθ=347.74 KJ/moL;Pine maleic anhydride ΔHfθ=-1303.47 KJ/moL,ΔGfθ=-514.59 KJ/moL.4.Use hot and heavy oxygen bombs and other measurement of the phase change temperature melting point is Tm=150℃ and standard levopimaric acid molar enthalpy of formation is ΔHfθ=-687 kJ/mol.Wherein the group contribution method(Joback(Chemdraw),C-G method and Benson method)standard molar enthalpy of formation calculated and experimental values of the measured standard molar enthalpy change of numerical error is extremely small,under 2%.5.The preliminary judgment was under Joback method,Gaussian law and the auxiliary Benson specific calculation method under terms of the thermodynamic.Gibbs energy change(ΔG<0,there is a possibility of spontaneous reaction)at.Guidance Levopimaric acid derivatives acrylpimaric pine acid and maleic anhydride synthesis,the results showed that the reaction acrylpimaric acid requiring temperature reaching to 180℃(theoretical temperature is 60℃,the reaction rate may be slower);maleopimaric anhydride reaction can be carried out at room temperature.