Patent ID: 8680232

Claim:
A method for preparing pimaric type resin acids, the method comprising: adding refined resin acids, pine oleoresin, or rosin, along with maleic anhydride at a mass ratio of 1:0.3-1.5 into a reaction bulb, dissolving them into a C 1 -C 10 lower fatty acid solvent, the mass ratio between the C 1 -C 10 lower fatty acid solvent and refined resin acids, pine oleoresin, or rosin is 0.05-30:1, and then performing an additive reaction under either microwave-assisted heating or direct heating, after the reaction, allowing the solution to cool down and form crystallized material, then filtering and washing the crystallized material; and combining the filtrate collected from filtering and washing, performing a reduced pressure distillation using the filtrate collected to remove the solvent and obtaining a crude product of pimaric type resin acids, dissolving the crude product of pimaric type resin acids in sodium hydroxide solution to produce a solution of pimaric type resin acids, adjusting the pH of the solution of pimaric type resin acids to around 6-14 using mineral acid or organic acid during agitation to produce precipitates, and purifying the obtained precipitates to obtain a final product of pimaric type resin acids, wherein the final product of pimaric type resin acids comprises a mixture of pimaric type resin acids.