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.

SummaryThe principal standard methods used by the American industry for the analysis and quality control of tall oil products have been discussed, and some of the work of the A.S.T.M. in developing these methods has been reviewed.Further growth of the tall oil industry will undoubtedly result in new products of greater refinement and wider utilization. New and improved methods of analysis will be required. These can be worked out by the industry in continued collaborative work under the auspices of the A.S.T.M. and A.O.C.S. Undoubtedly instrumental test methods such as infrared and ultraviolet spectroscopy and gas chromatography will play a role of increasing importance in the analysis of tall oil products.

SummaryTall oil processing is a relatively new and rapidly growing industry. Based on a stable supply of raw material from the kraft paper industry, it provides an important source of rosin and fatty acid products. The processes most generally employed in the United States are acid refining, distillation, and separation by fractional distillation.Tall oil refining techniques have advanced to the point where fatty acids substantially free from rosin acids and rosin substantially free from fatty acids are produced. With continued growth of the industry and further advances in tall oil technology, products of even greater refinement and wider utility may be expected in the not too distant future.