Products obtained by acid clay catalyzed dimerization of oleic, elaidic, and tall oil fatty acids were characterized. The monomeric products (35% of total) consisted of stearic, octadecenoic (66% trans-), and mid chain monomethyl branched acids, both saturated and unsaturated. The polymeric products (65% of total) consisted of linear, alicyclic, aromatic, and polycyclic dimers. The tall oil fatty acid based dimer closely resembled oleic dimer in polycyclic character and linoleic dimer in aromatic and linear structures. Oleic dimers contained the highest linear structural content, while linoleic dimer contained the largest polycyclic content. Alicyclic structures were the principal components of all three products. The monocyclic dimer structures present consisted of six membered ring systems with linoleic and tall oil fatty acid dimers containing the highest aromatic contents.

However, C and N analysis could be carried out in 90 seconds (see Figure 3). Table I1 is a comparison of this procedure with others reported in the literature.Certainly a standa-d deviation of 1.0.17 for N is not realistic based on the results of only a few samples, but it does indicate that the procedure works and is not out of line with previous work. The next step in the overall procedure is to add halogens to the system.

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The acid clay catalyzed dimerization of tall oil fatty acids and oleic acid yields commercial products which are complex mixtures of monomers, dimers, trimers, and higher polymers of various structures. Analyses for monomer, dimer, and trimer concentrations are important to ensure good quality control and reproducible end use performance. Techniques for direct determination of monomer, dimer, and trimer acids by gel permeation chromatography are presented. The components are separated using Bio Beads SX-2 gel. Heptanoic acid is used as an internal standard. The standard deviations for determination of dimer, trimer, and monomer are 1.0, 0.4, and 0.2% respectively. Calibration was accomplished using dimer and trimer fractions isolated from a preparative scale chromatographic system. It is suggested that a measure of higher polymeric acids can be obtained by difference after correction for neutral materials.

Acetal formation in conjunction with ultraviolet spectrophotometry has been employed as a convenient and useful analytical tool for the characterization and determination of aldehydes. The ultraviolet spectra of acetals formed from aldehydes in solutions of acidified methanol are significantly different from the spectra of the parent alde-