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- Hydroxyl_value abstract "In analytical chemistry, the hydroxyl value is defined as the number of milligrams of potassium hydroxide required to neutralize the acetic acid taken up on acetylation of one gram of a chemical substance that contains free hydroxyl groups. Hydroxyl value is a measure of the content of free hydroxyl groups in a chemical substance, usually expressed in units of the mass of potassium hydroxide (KOH) in milligrams equivalent to the hydroxyl content of one gram of the chemical substance. The analytical method used to determine hydroxyl value traditionally involves acetylation of the free hydroxyl groups of the substance with acetic anhydride in pyridine solvent. After completion of the reaction, water is added, and the remaining unreacted acetic anhydride is converted to acetic acid and measured by titration with potassium hydroxide. The hydroxyl value can be calculated using the following equation. Note that a chemical substance may also have a measurable acid value affecting the measured end point of the titration. The acid value (AV) of the substance, determined in a separate experiment, enters into this equation as a correction factor in the calculation of the hydroxyl value (HV):Where HV is the hydroxyl value; VB is the amount (ml) potassium hydroxide solution required for the titration of the blank; Vacet is the amount (ml) of potassium hydroxide solution required for the titration of the acetylated sample; Wacet is the weight of sample (in grams) used for acetylation; N is the normality of the titrant; 56.1 is the molecular weight of potassium hydroxide; AV is a separately determined acid value of the chemical substance.The content of free hydroxyl groups in a substance can also be determined by methods other than acetylation. Determinations of hydroxyl content by other methods may instead be expressed as a weight percentage (wt. %) of hydroxyl groups in units of the mass of hydroxide functional groups in grams per 100 grams of substance. The conversion between hydroxyl value and other hydroxyl content measurements is obtained by multiplying the hydroxyl value by the factor 17/560. The chemical substance may be a fat, oil, natural or synthetic ester, or other polyol. ASTM D 1957 and ASTM E222-10 describe several versions of this method of determining hydroxyl value.".
- Hydroxyl_value wikiPageID "33381675".
- Hydroxyl_value wikiPageRevisionID "588166174".
- Hydroxyl_value hasPhotoCollection Hydroxyl_value.
- Hydroxyl_value subject Category:Analytical_chemistry.
- Hydroxyl_value subject Category:Dimensionless_numbers_of_chemistry.
- Hydroxyl_value subject Category:Lipids.
- Hydroxyl_value type Abstraction100002137.
- Hydroxyl_value type Chemical114806838.
- Hydroxyl_value type Compound114818238.
- Hydroxyl_value type Lipid114938907.
- Hydroxyl_value type Lipids.
- Hydroxyl_value type Macromolecule114944888.
- Hydroxyl_value type Material114580897.
- Hydroxyl_value type Matter100020827.
- Hydroxyl_value type Molecule114682133.
- Hydroxyl_value type OrganicCompound114727670.
- Hydroxyl_value type Part113809207.
- Hydroxyl_value type PhysicalEntity100001930.
- Hydroxyl_value type Relation100031921.
- Hydroxyl_value type Substance100019613.
- Hydroxyl_value type Thing100002452.
- Hydroxyl_value type Unit109465459.
- Hydroxyl_value comment "In analytical chemistry, the hydroxyl value is defined as the number of milligrams of potassium hydroxide required to neutralize the acetic acid taken up on acetylation of one gram of a chemical substance that contains free hydroxyl groups. Hydroxyl value is a measure of the content of free hydroxyl groups in a chemical substance, usually expressed in units of the mass of potassium hydroxide (KOH) in milligrams equivalent to the hydroxyl content of one gram of the chemical substance.".
- Hydroxyl_value label "Hydroxyl value".
- Hydroxyl_value label "Hydroxylzahl".
- Hydroxyl_value sameAs Hydroxylzahl.
- Hydroxyl_value sameAs m.0h95kl4.
- Hydroxyl_value sameAs Q906044.
- Hydroxyl_value sameAs Q906044.
- Hydroxyl_value sameAs Hydroxyl_value.
- Hydroxyl_value wasDerivedFrom Hydroxyl_value?oldid=588166174.
- Hydroxyl_value isPrimaryTopicOf Hydroxyl_value.