Saponification Value Essential

Trinidad asphalt has a relatively uniform composition of 29% water and gas, 39% bitumen soluble in carbon disulfide, 27% mineral matter on ignition, and 5% bitumen that remains adsorbed on the mineral matter. Refining is essentially a process of dehydration by heating the cmde asphalt to ca 165°C. The refined product averages 36% mineral ash with a penetration at 25°C of about 2 (0.2 mm), a softening point (ring and ball method) of 99°C, a flash point (Cleveland open cup) of 254°C, a sulfur content of 3.3%, and a saponification value of 45 mg KOH/g. The mineral matter typically contains... 

It is soluble in about 5 volumes of 70 per cent, alcohol. This ester has the character of being saponified much more slowly than most other esters, so that in any determination in which it is involved it is necessary to saponify the sample for two hours before it is safe to consider the reaction complete. This fact also assists in determining whether terpinyl acetate is present as an adulterant in natural essential oils, for if the saponification value as determined by thirty minutes saponification is materially lower than that as determined by a two hours saponification, it may be fairly safely inferred that terpinyl acetate or some similar ester is present. 

Strictly speaking the amount of free acids present in an essential oil should be determined, and the acid value deducted from the saponification value, the difference being the ester value. 

Saponification Value Determine as directed for Saponification Value under Essential Oils and Flavors, Appendix VI, using 1.5 g accurately weighed. 

Properties Yellow to brownish-yellow essential oil. D 0.959-0.970 (15C), refr index 1.503-1.510, saponification value 6-20. Slightly soluble in water. 

Composition of oil/fat. To study the composition of oil/fat it is essential to test the purity of an oil/ fat for adulteration, accidentally or voluntarily. The specific fatty acid in fat can be determined by GC by preparing methyl esters with sodium methoxide. Mass spectrometry coupled to GC (GC-MS) is the most powerful tool for identification of fatty acids separated by GC. Free fatty acids in oil (index of rancidity) can be determined by titration against standard alkali. Infrared (IR) spectroscopy, Raman spectroscopy, and ultraviolet (UV) spectroscopy (200—400 nm) are used to detect isomers (trans and cis) of unsaturated fatty acids and conjugated double bonds. It is important to study saponification value (depict fatty acid chain length), iodine value (give the degree of unsaturation), and hydroxyl value (free fatty acids present in fats). 

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