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| | I'm Kristin and I live with my husband and our three children in Macari, in the TP south area. My hobbies are Ice hockey, Bridge and Boxing.<br><br>Feel free to visit my web site ... [http://Www.sundaydiary.com/fifa-15-coin-hack-2 FIFA 15 Coin hack] |
| In [[chemistry]], '''acid value''' (or "neutralization number" or "acid number" or "acidity") is the mass of [[potassium hydroxide]] (KOH) in [[milligrams]] that is required to neutralize one gram of [[chemical substance]]. The acid number is a measure of the amount of [[carboxylic acid]] groups in a chemical compound, such as a [[fatty acid]], or in a mixture of compounds. In a typical procedure, a known amount of sample dissolved in organic solvent (often [[isopropyl alcohol|isopropanol]]), is [[titration|titrated]] with a solution of potassium hydroxide with known [[concentration]] and with [[phenolphthalein]] as a color indicator.
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| The acid number is used to quantify the amount of acid present, for example in a sample of [[biodiesel]]. It is the quantity of base, expressed in milligrams of potassium hydroxide, that is required to neutralize the acidic constituents in 1 g of sample.
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| :<math>AN=(V_{eq}-b_{eq})N\frac{56.1}{W_{oil}}</math>
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| V<sub>eq</sub> is the volume of [[titration|titrant]] (ml) consumed by the crude oil sample and 1 ml of spiking solution at the equivalent point, b<sub>eq</sub> is the volume of titrant (ml) consumed by 1 ml of [[spiking solution]] at the equivalent point, and 56.1 is the molecular weight of [[Potassium hydroxide|KOH]]. W<sub>Oil</sub> is the mass of the sample in grams.
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| The molar concentration of titrant (N) is calculated as such:
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| :<math>N=\frac{1000W_{KHP}}{204.23V_{eq}}</math>
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| In which W<sub>KHP</sub> is the mass (g) of [[KHP]] in 50 ml of KHP standard solution, V<sub>eq</sub> is the volume of titrant (ml) consumed by 50 ml KHP standard solution at the equivalent point, and 204.23 is the molecular weight of KHP.
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| There are standard methods for determining the acid number, such as [[ASTM]] D 974 and [[DIN]] 51558 (for mineral oils, biodiesel), or specifically for Biodiesel using the European Standard EN 14104 and ASTM D664 are both widely utilised worldwide.
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| Acid number (mg [[Potassium hydroxide|KOH]]/g oil) for [[biodiesel]] should to be lower than 0.50 mg KOH/g in both EN 14214 and ASTM D6751 standard fuels. This is since the FFA produced may corrode automotive parts and these limits protect vehicle engines and fuel tanks.
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| As oil-fats [[rancidity|rancidify]], [[triglyceride]]s are converted into [[fatty acid]]s and [[glycerol]], causing an increase in acid number. A similar observation is observed with biodiesel aging through analogous oxidation processes and when subjected to prolonged high temperatures (ester thermolysis) or through exposure to acids or bases (acid/base ester [[hydrolysis]]).
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| ==See also==
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| * [[Saponification value]]
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| * [[Hydroxyl value]]
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| * [[Iodine value]]
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| * [[Total acid number]]
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| * [[Oxidation]]
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| * [[EN 14214]]
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| {{DEFAULTSORT:Acid Value}}
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| [[Category:Analytical chemistry]]
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| [[Category:Lipids]]
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