Getting an organic acids
Properties of organic acids
|Getting an organic acids||Acetic acid||Stearic acid||Hydrocyanic acid
|Formic acid||Amino acids||lemon acid||Silicic acid|
Carboxylic acidCarboxylic acids (or organic acids) are derivatives of hydrocarbons, that have a carboxyl group (- COOH) in molecules.
All carboxylic acids are organic compounds. A typical example is acetic acid - CH3-COOH, formic acid CHOOH, propane (or propionata) CH3-CH2-COOH, oil (or butane) CH3-CH2-CH2-COOH acid.
Chemical properties of organic acids is determined by the structure of the functional group (carboxyl group), and these compounds are easily dissociated in solutions with the formation of hydrogen ions. Therefore, for carboxylic acids is characterized by all of the same properties as that of mineral acids.
Properties of organic acids
- reaction with some metals (we heve salt and hydrogen)
Getting an carboxylic acidsGetting an carboxylic acids from aldehydes, that are got by oxidation of alcohol. The reaction proceeds:
- this is the oxidation reaction of ethanol with oxygen.
- this oxidation reaction of acetic aldehyde with oxygen.
Getting an carboxylic acids hydrolysis nitriles: the reaction takes place with the action water to nitriles. The second product of the reaction is ammonia:
In addition, in this reaction (intermediate product) is formed of a highly unstable triatomic alcohol, that has a molecule with three hydroxyl groups at only one carbon atom.
During the hydrolysis of esters we also get carboxylic acids. The Second product of it reaction is alcohol. To shift the equilibrium of the reaction can use lye, but this way we will get not carboxylic acid, but its salt. If the salt is treated with a strong mineral acid (e.g., hydrochloric), we get a carboxylic acid.
Stearic acidAll probably know stearic acid. This substance, insoluble in water, gray color (think about candles!). It is a weak acid. Stearic acid can be got with acting on the soap solution with any other acid. For example, if to soap solution add acetic acid, it is possible to observe gray precipitation, it will be stearic acid:
C17H35COONa + CH3COOH => C17H35COOH (precipitation) + CH3COONa
In this reaction C17H35COONa - solution of solid natural soap (for wash hands). In chemical terms the soap is sodium stearate. Similarly, other salt of stearic acid are called stearates.
Lemon acidLemon acid (chemical formula is HOOCCH2)2C(OH)COOH) forms large colourless, transparent crystals, soluble in water and in ethyl alcohol. Salt of lemon acid (citric acid) are called citrates.
Most often citric acid is used as flavor additives for confectionery products. When mixing citric acid and baking soda (NaHCO3) we get carbon dioxide (especially when heated), that loosens the dough.
Citric acid (lemon acid) can also used for removing ink stains and rust.
Salt - citrate of iron - colorless substances, are soluble in water. This property is used for removing rust spots.
Carboxyl group (sometimes write as COOH)
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