Institute of Chemical Industry of Forest Products, Caf

Chinese Academy of Forestry

Liangwu Bi

Yuxiang Chen

Zhendong Zhao

Jing Wang

Yan Gu

Dongmei Li

Yanju Lu

Shouji Zhu

Xingdi Li

Shichao Xu

This invention discloses a type of 1,8-bis(Schiff base)-p-menthane derivatives as well as their preparation method and applications. The reaction of 1,8-diamino-p-menthane with a substituted benzaldehyde was carried out in a polar organic solvent at 0&#xb0; C.-75&#xb0; C. for 1-48 h. After the completion of the reaction, part of the solvent was distilled off to perform recrystallization to get a 1,8-bis(Schiff base)-p-menthane derivative, whose pre-emergence herbicidal activity against ryegrass was determined by using the Petri dish seed germination method. The 1,8-bis(Schiff base)-p-menthane derivatives, obtained with this method in high yield and mild reaction conditions, have a good inhibitory effect on the growth of annual ryegrass, and low toxicity.

1,8-bis(Schiff base)-p-menthane derivatives as well as preparation method and applications thereof

Disclosed is a process for preparing isopimaric acid, comprising the following steps: First step: dissolving thermally isomerized rosin in acetone, adding in drops a solution of isobutanolamine in acetone to form a precipitate, standing, filtering, washing with ethanol, and drying to obtain crude ammonium salt of isopimaric acid; recrystallizing the crude ammonium salt of isopimaric acid according to multi-recrystallization, and drying to obtain purified crystal of ammonium salt of isopimaric acid; Second step: dissolving the purified crystal of ammonium salt of isopimaric acid obtained in the first step in ether, adding hydrochloric acid in portions until the crystal of ammonium salt of isopimaric acid disappears, removing a water layer and washing the ether layer with water to neutral, evaporating the ether, dissolving the residue in acetone, adding water slowly into the solution dropwise until crystals cease to grow, then filtering and drying to obtain purified isopimaric acid.

Process for preparing isopimaric acid

A method for preparing pimaric acid type resin acids includes the following steps: step (1) adding refined resin acid, turpentine, or rosin along with maleic anhydride at a mass ratio of 1:0.3-1.5 into a reaction bottle, dissolving the ingredients into a C-Clower fatty acid solvent, the mass ratio of the C-Clow fatty acid to refined resin acid is 0.05-30:1, then carrying out additional reaction by heating directly or with assistance of a microwave, subsequently cooling, crystallizing, filtering, and washing; and step (2) combining the filtrates collected in step (1), stripping the solvent by vacuum distillation to obtain pimaric acid type resin acid coarse product, dissolving the resulting coarse product in NaOH aqueous solution to prepare aqueous solution of pimaric acid type resin acid salt, adjusting the pH level to 6-14 with a mineral acid or an organic acid while stirring, and either directly purifying or acidifying followed by purifying, the resulting precipitation to obtain the final product. The method has the characteristics of high yield, high product content, low cost, and low environmental pollution.

Preparation method of pimaric acid type resin acid

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Nanjing, China

Liangwu Bi