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Guilherme Mazui

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What is the Difference Between Acid Value and Saponification Value?

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The main difference between acid value and saponification value lies in what they measure and their applications. Here are the key differences:

  • Acid Value: This is a measure of the amount of free acid present in a substance. Lower values indicate freshness or purity, while higher values suggest rancidity or oxidation. Acid value is used to determine the acidity of a particular substance, such as fat or oil.
  • Saponification Value: This is a measure of the amount of alkali (specifically potassium hydroxide) needed to saponify a given amount of fat or oil. Saponification value gives an indication of the average molecular weight of the triglycerides in a fat or oil. Higher values indicate shorter chain lengths, while lower values suggest longer chain lengths.

Both acid value and saponification value are given in units of mass, specifically milligrams of potassium hydroxide (KOH). If the saponification value and the acid value have been determined, the difference between these two represents the Ester Value, which is the number of milligrams of potassium hydroxide required to saponify the esters in 1.0 g of the substance.

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  • What is the Difference Between Acid Value and Saponification Value?
  • Comparative Table: Acid Value vs Saponification Value

    • Comparative Table: Acid Value vs Saponification Value

    Here is a table summarizing the difference between acid value and saponification value:

    Acid Value Saponification Value
    Measures the amount of free acid present in a substance Measures the amount of alkali needed to saponify a given substance
    Indicates the degree of freshness or purity of the substance (lower values are better) Can give an indication of the average molecular weight of the substance
    Used to quantify the acidity of a substance, such as biodiesel Defined as the number of milligrams of KOH needed to neutralize the fatty acids obtained by complete hydrolysis of 1 gram of an oil

    Both acid value and saponification value are given as a mass (of potassium hydroxide) and are expressed in units of milligrams.

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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.