Study On The Preparation Of Disproportionated Rosin And Purification Of Dehydroabietic Acid From Disproportionated Rosin

The traditional method of producing disporportionated acid adopts the melt way that needs high temperature and leads to lower acidity in the product. And it is difficult to recycle the catalyst too. This research adopts the solvent method. It decreases the reaction temperature greatly and the addition of solvent will help to recycle the catalyst. As to the purification of dehydroabietic acid, the traditional method-crystal is adopted here. The product purity is high but the quality loss great too. Through the research, the improvement of dehydroabietic acid in disporportionated acid is advised to solve this problem. The more detail steps are listed as:The gas chromatography is selected to analyze the components in the disproportionated rosin. The settled conditions of chromatogram are showed as: BP 5 capeillary column of chromatogram; raising temperature by program: 423K 4K/min 493K 2K/min 533K; carrier gas and its flow rate: nitrogen gas, 45ml/min; pressure before columniation: 0.07Mpa; air's flow rate: 300ml/min; hydrogen gas flow rate: 30 ml/min; split stream ratio: 50:1; trail flow rate: 24 ml/min; Temperature of check machine: 533K; Temperature of boil room: 533K; sample volume: 1 L.The rosin is adopted as the reactant of disproportional reaction. The experiments are designed by perpendicularity method and evaluate the effect of temperature, catalyst, solvent, rotating velocity and time. After that, theexperiments are designed by single point method in order to find the best techniques conditions. The best techniques conditions detected are showed as: 0.25% (based on the quality of turpentine) Pd/C catalyst, 220 C of reaction temperature, 45% (based on the total quality) of 200# oil, 0.5MPa of protect gas, the 600r/min of rotation velocity and 210min of the reaction time. Under the conditions, it produces undertone-disproportionated rosin containing 69.1% dehydroabietic acid. Afterward, It adopts turpentine as the reactant. The best techniques conditions detected are showed as: 0.15% (based on the quality of turpentine) Pd/C catalyst, 250"C of reaction temperature, 41.9% (based on the total quality) oil of turpentine , 0.5MPa of protect gas, the 600r/min of rotation velocity and 60min of the reaction time. Under the conditions, it produces undertone-disproportionated rosin containing 74.8% dehydroabietic acid.About the purification of dehydroabietic acid, the disproportionated rosin was dissolved by alcohol; add alcohol amine and the deposition of dehydoabietylamine will be produced. The dehydoabietylamine is extracted byisooctane or 200 oil. After use 50 % alcohol to purify the dehydoabietylamine by repetitious crystal method, it is time to revert dehydoabietylamine to dehydroabietic acid by hydrochloric acid. Afterward the dehydroabietic acid was re-crystallized by 75 % alcohol. At last it produces above 98% dehydroabietic acid crystal. The quality is about 10% callback.