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Unsaponifiables are components of a fatty substance (oil, fat, wax) that fail to form soaps when treated with alkali and remain insoluble in water but soluble in organic solvents. For instance, typical soybean oil contains, by weight, 1.5 – 2.5% of unsaponifiable matter.
Oil paints are composed of pigment molecules suspended in an oil-binding medium. Heavy metal salts are often used as pigment molecules, such as in lead white , red lead , and zinc white . [ 8 ] If those heavy metal salts react with free fatty acids in the oil medium, metal soaps may form in a paint layer that can then migrate outward to the ...
The acid number for an oil sample is indicative of the age of the oil and can be used to determine when the oil must be changed. [5] A liquid fat sample combined with neutralized 95% ethanol is titrated with standardized sodium hydroxide of 0.1 eq/L normality to a phenolphthalein endpoint. The volume and normality of the sodium hydroxide are ...
Phenolphthalein is slightly soluble in water and usually is dissolved in alcohols in experiments. It is a weak acid, which can lose H + ions in solution. The nonionized phenolphthalein molecule is colorless and the double deprotonated phenolphthalein ion is fuchsia. Further proton loss in higher pH occurs slowly and leads to a colorless form.
The Reichert value is an indicator of how much volatile fatty acid can be extracted from a particular fat or oil through saponification. It is equal to the number of millilitres of 0.1 normal hydroxide solution necessary for the neutralization of the water-soluble volatile fatty acids distilled and filtered from 5 grams of a given saponified fat.
Grape seed oil: 216 °C: 421 °F Lard: 190 °C: 374 °F [5] Mustard oil: 250 °C: 480 °F [11] Olive oil: Refined: 199–243 °C: 390–470 °F [12] Olive oil: Virgin: 210 °C: 410 °F Olive oil: Extra virgin, low acidity, high quality: 207 °C: 405 °F [3] [13] Olive oil: Extra virgin: 190 °C: 374 °F [13] Palm oil: Fractionated: 235 °C [14 ...
The official technique to measure free acidity in olive oil (as defined by the European Commission regulation No. 2568/91) is a manual titration procedure: a known volume of the oil to be tested is added to a mix of ether, methanol and phenolphthalein.
Animation of a strong acid–strong base neutralization titration (using phenolphthalein). The equivalence point is marked in red. In chemistry, neutralization or neutralisation (see spelling differences) is a chemical reaction in which acid and a base react with an equivalent quantity of each other. In a reaction in water, neutralization ...