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[[Image:NaStearate.png|thumb|right|300px|Two equivalent images of the chemical structure of [[sodium stearate]], a typical soap.]] |
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[[Image:NaStearate.png|thumb|right|300px|Two equivalent images of the chemical structure of [[sodium stearate]], a typical soap.]] |
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In chemistry, '''soap''' is a [[salt (chemistry)|salt]] of a [[fatty acid]].<ref>[[IUPAC]]. "[http://goldbook.iupac.org/S05721.html ''IUPAC Gold Book – soap'']" ''Compendium of Chemical Terminology'', 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. {{doi|10.1351/goldbook}}. Accessed 2010-08-09</ref> Soaps are mainly used as [[surfactant]]s for [[washing]], [[bathing]], and [[housekeeping|cleaning]], but they are also used in textile spinning and are important components of [[lubricant]]s.
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'''soap''' is a [[salt (chemistry)|salt]] of a [[fatty acid]].<ref>[[IUPAC]]. "[http://goldbook.iupac.org/S05721.html ''IUPAC Gold Book – soap'']" ''Compendium of Chemical Terminology'', 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. {{doi|10.1351/goldbook}}. Accessed 2010-08-09</ref> Soaps are mainly used as [[surfactant]]s for [[washing]], [[bathing]], and [[housekeeping|cleaning]], but they are also used in textile spinning and are important components of [[lubricant]]s. |
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Soaps for cleansing are obtained by treating vegetable or animal oils and fats with a strongly [[Alkalinity|alkaline]] solution. Fats and oils are composed of [[triglyceride]]s; three molecules of [[fatty acids]] are attached to a single molecule of [[glycerol]].<ref name="Cavitch, Susan Miller 1994">Cavitch, Susan Miller. ''The Natural Soap Book''. Storey Publishing, 1994 ISBN 0-88266-888-9.</ref> The alkaline solution, which is often called [[lye]] (although the term "lye soap" refers almost exclusively to soaps made with [[sodium hydroxide]]), brings about a [[chemical reaction]] known as [[saponification]]. In this reaction, the triglyceride fats are first hydrolyzed into free fatty acids, and then these combine with the alkali to form crude soap, an amalgam of various soap salts, excess fat or alkali, water, and liberated [[glycerol]] (glycerin). The glycerin is a useful by-product, which can be left in the soap product as a softening agent, or isolated for other uses.<ref name="Cavitch, Susan Miller 1994"/> |
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Soaps for cleansing are obtained by treating vegetable or animal oils and fats with a strongly [[Alkalinity|alkaline]] solution. Fats and oils are composed of [[triglyceride]]s; three molecules of [[fatty acids]] are attached to a single molecule of [[glycerol]].<ref name="Cavitch, Susan Miller 1994">Cavitch, Susan Miller. ''The Natural Soap Book''. Storey Publishing, 1994 ISBN 0-88266-888-9.</ref> The alkaline solution, which is often called [[lye]] (although the term "lye soap" refers almost exclusively to soaps made with [[sodium hydroxide]]), brings about a [[chemical reaction]] known as [[saponification]]. In this reaction, the triglyceride fats are first hydrolyzed into free fatty acids, and then these combine with the alkali to form crude soap, an amalgam of various soap salts, excess fat or alkali, water, and liberated [[glycerol]] (glycerin). The glycerin is a useful by-product, which can be left in the soap product as a softening agent, or isolated for other uses.<ref name="Cavitch, Susan Miller 1994"/> |