Separation And Selective Oxidation Of Rosin Acids

The research on separation of rosin acids from gum rosin or pine oleoresin and low cost synthesis of rosin acids derivatives having multiple functional groups by oxidation of the C=C double bonds is one of the important directions having good prospects in deep-processing of gum rosin. The low yield and complicated separation process and oxidation selectivity of rosin acids has become the bottle-neck problem in the basic research and industrial application of oxidation modification of rosin acids.The paper takes levopimaric acid and abietic acid as representative rosin acids to study the method for simplifying the separation processing of rosin acids and improving the selectivity of oxidation reaction according to the green chemistry principles. The results showed that ethyl acetate could be used as a substitute for acetone to yield more butanolamine salt of levopimaric acid and levopimaric acid products by improving the crystal phase and filtration performance of butanolamine salt precipitates;Perfluorinated sulphonate resin membrane could be used as solid acid to catalyze the isomerization reaction of rosin acids in 95 % alcohol and to obtain abietic acid in 94 % purity and 35 % yield by direct cool crystallization; the process of separating rosin acids mixtures from gum rosin or Pine Oleoresin for purifying rosin and preparing abietic acid could be simplified by a precipitation separation method, in which Gum rosin or Pine Oleoresin were dissolved in a good solvent and added a poor solvent; Photo-sensitized oxidation reaction of 2-amino-2-methyl-1-propanol salt of levopimaric acid in 95 % ethanol could be carried out in order to simplify the process of separating levopimaric acid from pine oleoresin and preparing levopimaric acid transannular peroxide; oxidation reaction of abietic acid and its methyl esters could be easily carried out by using quaternary ammonium salts of heteropoly acids as catalyst and 30 % H2O2 as oxidant, and gave epoxides in good yield and selectivity at the optimized reaction conditions.