Diamylamine salt

Abietic acid has usually been prepared 2 from rosin through the acid sodium salt (3C20H30O2 C19H2weak acid such as acetic acid. 

Abietic ACID, 32, 1 add sodium salt of, 32, 4 diamylamine salt of, 32, 2 Acetaldehyde, 36, 60 Acetaldehyde, diphenyl-, 38, 26 Acetal diethyl, of acetylenic aldehydes, 39, 60... 

The isomerized rosin, 245 g. (0.72 mole) (Note 1), is placed in a 1-1. Erlenmeyer flask and dissolved in 375 ml. of acetone by heating the mixture on a steam bath. To this solution, at incipient boiling, is added slowly and with vigorous agitation (Note 5) 127 g. (0.81 mole) of diamylamine 2 (Note 6). Upon cooling to room temperature, crystals appear in the form of rosettes. The mass is agitated, cooled well in an ice bath, and filtered by suction. The crystalline salt is washed on a Buchner funnel with 150 ml. of acetone and dried in a vacuum oven at 50° for 1 hour. The optical rotation of this material is [< ]d —18° (Note 4). The solid is recrystallized four times from acetone. Each time a sufficient quantity (20 ml. per g.) of acetone is used to obtain complete solution, and the solvent is evaporated until incipient precipitation of the salt occurs. The yield of product is 118 g. [ ]d —60° (Note 4). An additional 29 g. of product, having the same rotation, can be recovered from filtrates of the previous crystallizations. 

Props methods of prepn of diamylamine and of other salts are given in Refs 1, 3 4 Refs 1) Beil 4, (378), [642] 1330 ... 

Abietic acid is conveniently isolated from acid-isomerized wood rosin by slowly adding commercial diamylamine to a stirred solution of the material in acetone. The salt which separates (aD —18°) is crystallized four times from acetone and the purified salt (oD —60°) is treated in ethanol with acetic acid and water. After recrystallization from dilute ethanol the yield of abietic acid is 40%. 

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