The determination of rosin in fatty acids

Abstract

SummaryA new method is described for the determination of rosin acids in fatty acids over a range of 0–15%.The method is based on an acid‐catalyzed selective esterification of a large sample, removal of the acid catalyst, titration of the unesterified rosin acids, and application of an empirical correction factor to the results.Excellent agreement is obtained between various analysts, and the rosin acids content can be determined to within ±0.1%.Examination of the McNicoll and Wolff indicator methods showed these methods unreliable in the range of 0–15% rosin acids. The McNicoll method gave values which were from .5–1% low and the Wolff method 2–3% high.It is anticipated that the new method, which covers a rosin acids range that is becoming more important industrially as the technology of tall oil separation advances, will prove useful to workers in this field and to those interested in the accurate determination of rosin acids in other products.

Capillary gas chromatography‐mass spectrometry of resin acids in tall oil rosin

“…The rosin samples investigated had acid numbers, 154. 5-157.7 (13); saponification numbers, 163.9-174.4 (14); and resin acid contents, 79.2-81.4% (15). Corresponding samples of crude tall oil gave acid numbers, 148.6-150.0 (plant A) and 134.2 (plant B); saponification numbers, 156.0-157.0 (A) and 162.8 (B); and resin acid contents 38.2-39.9%.…”