DIFFERENTIAL SCANNING CALORIMETRY INDEX FOR ESTIMATING LEVEL OF SATURATION IN TRANSESTERIFIED WAX ESTERS

Differential scanning calorimetry (DSC) thermograms of fatty esters ca n give valuable information on melting characteristics and heats-of-fu sion enthalpy (Delta H). A series of jojoba liquid wax esters was cons tructed by transesterifying native jojoba oil with 5-50% completely hy drogenated jojoba wax esters. This series, when subjected to a standar dized DSC tempering method with heating/cooling cycles, exhibited an e xcellent correlation for level of saturation based on area changes in endothermic Delta H. Endothermic events were recorded for native (Delt a H-A) and completely hydrogenated (Delta H-C) jojoba wax esters. A th ird endotherm, Delta H-B, was observed when they were transesterified. Based on a multiple regression program, the best fit (R(2) = 0.98) us ing Delta H data was: % saturation = 16.847 - 0.162 (Delta H-A) + 0.20 9 (Delta H-B) + 0.600 (Delta H-C). Standard errors for predictions wer e approximately 1.045 at 0% saturation, 0.770 at 25% saturation, and 1 .158 at 50% saturation. Endothermic events A, B, and C each represent the respective di-unsaturated, monounsaturated, and saturated contents of wax esters in the transesterified blends. This was verified by mea suring the dropping points for both the native and completely hydrogen ated wax esters. These findings provide an index which can predict the degree of saturation in transesterified wax ester blends and serves a s a research tool in process and product developments.