A study of the Ellis-Jones Maleic anhydride method and its use in testing tung oil

The spectrophotometric determination of the alpha and beta isomers of eleostearic acid in tung oil

“…Error due to the critical dependency of wave-length setting and to spectrum band isolation has already been pointed out. The values for total eleostearic acid in various tung oils obtained spectrophotometrically are compared in Table 2 with those obtained by chemical means based on maleic anhydride values (14). The two sets of values are only in fair agreement.…”

Spectrophotometric Determination of Alpha-Eleostearic Acid in Freshly Extracted Tung Oil Determination of Extinction Coefficients in Oil Solvents

“…As suitable coefficients for -eleostearic acid in oil solvents were now available, they were tested by the measurement of a few tung oil samples for the -eleostearic acid content. Table II shows the results obtained, together with corresponding values by use of the chemical method of Ellis and Jones (8,19).…”

“…Per cent concentration = °P^caj density ^100 alpha cl The agreement between the values obtained from measurements in iso-octane and in cyclohexane proves the self-consistency of the reported extinction coefficients in these two solvents. As maleic anhydride values are only claimed to permit "fair approximation of the per cent tung oil" or to "serve as a means for detecting and roughly estimating adulteration of tung oil" (19), no attempts have been made to explain the differences between the per cent of -eleostearic acid obtained ffom these values and those obtained by the direct spectrophotometric methods described. To test the accuracy of the method over a range of a- eleostearic acid concentrations which might be encountered in various fresh tung oil samples, admixtures of tung oil and mineral oil were prepared and spectrophotometrically measured and the -eleostearic acid content was determined.…”

“…Consequently, most tests of quality of tung oil samples are methods for estimating -eleostearic acid content. In common use are: Toms' method (S3) by Wijs iodine number and by bromine vapor values; Kaufmann's method (15) from thiocyanogen and bromine numbers; Bolton and Williams' method (S) from so-called "instantaneous iodine numbers"; the diene method of Kaufmann and Baltes (16); and Ellis and Jones' method (8,19) from maleic anhydride values. All these methods are indirect and require very time-consuming chemical operations.…”

PRODUCT AND PROCESS DEVELOPMENT Liquid Polybutadiene

“…Hardness number of drawing pencil required to dent dried film. b Percentage of film not removed by pressing on and removing Scotch tape 6. Arbitrary rating -0 = no stain; 4 = very severe staining.i v i d u a l n o t d i r e c t l y a s s o c i a t e d w i t h s c i t e i s p r o h i b i t e d .…”