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Primary Applications for the Carboxylic Acids - 2
Carboxylic acids have multiple applications in the industry
Subject: Primary Applications for the Carboxylic Acids
Stearic Acid
Stearic acid is organic, solid white and crystal-like, with the formula CH3(CH2)16COOH. It is not soluble in water but is soluble in alcohol and ether. Along with lauric, myristic and palmitic acids, stearic acid is part of an important group of fatty acids. It is abundant in most oils and fats of animals and plants in the form of esters, such as glyceryl tristearate ester or stearin, and constitutes the major part of the fat in foods and the human body.
Stearic acid is obtained by hydrolysis of the ester, and commercially is prepared by the hydrolysis of tallow. It is used in lubricant mixtures, water-resistant materials, desiccants of varnishes, and in the manufacture of paraffin candles. Stearic acid combined with sodium hydroxide stearic acid forms soap (sodium stearate).
Stearic acid is used to combine natural or synthetic rubber with other substances such as pigments or materials that control the flexibility of rubber products. It is used in the polymerization of styrene and butadiene for synthetic rubber. For more information, click here
Ethanoic Acid or Acetic Acid
A colorless liquid with the formula CH3COOH, ethanoic acid has an irritating odor and a bitter taste. In an aqueous solution it acts as a weak acid. Pure ethanoic acid is called glacial ethanoic acid, because it freezes at temperatures slightly lower than room temperature. When mixed with water it freezes at much lower temperatures. Ethanoic acid is miscible (mixable) with water and many organic solvents.
Diluted solutions (4 to 8%) of ethanoic acid are used to make vinegar from wine, cider or malt. Concentrated ethanoic acid is prepared industrially by different processes, including the reaction of methanol (methyl alcohol) and carbon monoxide (CO) in the presence of a catalyst, and by the oxidation of ethanal (acetaldehyde).
Ethanoic acid is used in the production of acetate rayon, plastics, photographic film, paint thinners, and medications such as aspirin. It has a boiling point of 118 ° C and a melting point of 17 ° C. For more information click here
Lactic Acid or 2-Hydroxypropanoic Acid
Lactic acid is a colorless compound with the formula CH3CH(OH)COOH, which occurs in two optically active forms, right-handed and left-handed, commonly called a D-lactic acid and L-lactic acid. In its natural state, it is an optically inactive mixture composed of equal parts, known as a racemic mixture, of both D- and L- forms.
Lactic acid is formed in milk by the fermentation of lactose which can make it sour. It is used to make cheese, sauerkraut, choucroute, soft drinks and other foodstuffs. For more information, click here
Malic Acid
Malic acid is hydroxybutanedioic acid, a colorless compound with the formula HO2CCH2CHOHCO2H. It has a melting point of 100° C and is soluble in water and alcohol. It exists in two optically active forms, although the L-malic acid (levorotatory isomer) is the only one that exists naturally.
Malic acid is found in apples, grapes, green cherries and many other fruits, as well as in wine. It can be obtained synthetically from tartaric acid and succinic acid. When heated and dehydrated it produces fumaric acid and maleic acid.
It is used as food additive for its antibacterial action and pleasant aroma. It is also used in medicine in the manufacture of certain laxatives and to treat sore throats. For more information, click here
Formic Acid or Methanoic Acid
The simplest of organic acids, formic acid has a chemical formula of HCO2H. It is a colorless liquid with an irritating odor and boiling and freezing points at 100.7º C and 8.4º C respectively. It is prepared commercially by reacting carbon dioxide with carbon monoxide at a high temperature and pressure. Formic acid is widely used in the chemical industry, as well as for dyeing and leather tanning. In nature, formic acid appears in the venom of ants and nettles. For more information, click here
Oxalic Acid
Also known as ethanedioic acid, oxalic acid has a chemical formula of HO2CCO2H and is a colorless solid which crystallizes with two molecules of water. At 100° C it loses its crystallization, and the anhydrous acid melts at 190° C.
Oxalic acid is found in many plants in the form of salts (oxalates) of potassium. Its calcium salt also appears in certain vegetables and in kidney stones. It is used in chemical analysis for its reduction power and especially in the determination of magnesium and calcium. It is also used in dyeing, in tanning, in the synthesis of dyes and as a stripper. For more information, click here
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