Surface tension determinations of some saturated fat acid methyl esters

Abstract

Summary Methyl esters of saturated naturally occurring fat acids from C6 through C18 were prepared and purified by fractional distillation. Refractive indices were used as a measure of their purity. A micro surface tension apparatus was constructed to comply with a modified capillary rise method devised by Ferguson. The surface tensions of water and of benzene were determined at several temperatures. The results obtained compared quite favorably with the values listed in the International Critical Tables. The surface tensions of the methyl esters were determined at 40°C., 60°C., and 80°C. with an accuracy of ±0.15 dynes/cm. Similar to other homologous series the surface tensions of the fat acid methyl esters decrease with increasing temperature, apparently in a linear manner. As the molecular weight of the methyl ester series increases, the surface tension also increases. Close correlation is shown for the methyl esters between the calculated parachors based upon Gibling's system of values and the experimental parachors.

Surface Tension Studies of Alkyl Esters and Epoxidized Alkyl Esters Relevant to Oleochemically Based Fuel Additives

“…Length of Headgroup. Changes in either the size or the configuration of the alkyl headgroup in alkyl methyl esters has been shown to dramatically effect properties such as cloud point, pour point, , and lubricity. , The surface tensions of the methyl ester, ethyl ester, and fatty acids of many oleochemicals have been reported, − but not much has been done with larger headgroups. The difference between methyl and ethyl esters is quite small, always within 0.5 mN m -1 at 75 °C.…”

“…Many valuable surface studies have been done on saturated fatty acids or esters, − while much less has been reported on their unsaturated , counterparts and none is available for epoxidized fatty ester materials. Herein, we report the surface tensions of various epoxidized oleochemicals (Figure ), including epoxidized methyl oleate (EMO; methyl 9,10-epoxy stearate), epoxidized methyl linoleate (EMLO; methyl 9,10,12,13-diepoxy stearate), and epoxidized soybean oil methyl esters (ESME), as well as similar results for a comparable set of the parent olefins.…”

Measurements and Reference Correlation of the Density and Speed of Sound and Derived Thermodynamic Properties of Methyl Laurate and Methyl Stearate

“…Probably, the large discrepancy (0.45%) of the data reported by Nevin et al 28 is due to the effect of impurities on the measured properties or incorrect calibration of the instrument. These data 28 are systematically higher than the present, and all other reported data by 0.28%. All reported speed of sound data points (32 data points) [24][25][26]32 for methyl laurate (see Table 1), except for the data reported by Tat and van Gerpen, 1 were included in the primary set.…”

“…Due to their inconsistency, some data sources were excluded from the primary set. For example, Nevin et al 28 (3 data points) was excluded from the primary data due to a large discrepancy (within 0.2−0.3%) with other reported data. The purity of the studied samples has not been provided by the authors.…”

“…There are limited and inconsistent thermodynamic property data for methyl laurate and methyl stearate in the literature. The summary of all of the reported literature density and speed of sound data ,− sources for methyl laurate and methyl stearate are given in Tables and . Relatively little data has been published on the density and speed of sound of methyl laurate and methyl stearate.…”