Polyatomic alcohols - extensive group of chemical compounds which molecules incorporate more than one hydroxyl group. These substances have broad practical application in various industries.
Polyatomic alcohols are organic compounds in which one molecule there are several hydroxyl groups. The most ordinary representative of this group of chemical compound is diatomic ethylene glycol, or etandiol-1.2.
Physical properties
These properties in many respects depend on the structure of a hydrocarbon radical of alcohol, the number of hydroxyl groups and also their situation. Thus, the first representatives of a homological row are liquids, and the highest are solid substances.
If one-atomic alcohols easily mix up with water, then at polyatomic this process happens more slowly and at increase in molecular mass of substance gradually comes to naught. At the expense of stronger association of molecules in similar substances, so and emergence enough strong hydrogen communications, temperature of boiling of alcohols is high. Dissociation on ions proceeds in so small degree that alcohols give neutral reaction – coloring of litmus or phenolphthalein does not change.
Chemical properties
Chemical properties of these alcohols are similar to that one-atomic, that is they react nucleophilic replacement, dehydration and oxidation to aldehydes or ketones. The last is excluded at triatomic alcohols which oxidation is followed by destruction of a hydrocarbon skeleton. High-quality reaction to polyatomic alcohols is carried out with hydroxide of copper (II). At addition of the indicator in alcohol, the chelate complex of bright blue color drops out.
Ways of receiving polyatomic alcohols
Synthesis of these substances is possible by restoration of monosaccharides and also condensation of aldehydes with formalin in the alkaline environment. I receive quite often polyatomic alcohols also from natural raw materials – rowan fruits. The most common polyatomic alcohol – glycerin – is received by splitting of fats, and with introduction new by technologies in chemical industry – a synthetic way from the propylene which is formed in the course of cracking of oil products.
Use of polyatomic alcohols
Areas of application of polyatomic alcohols are various. Eritrit use for preparation of explosives, quick-drying paints. Xylitol is widely used in the food industry at preparation of diabetic products and also in production of pitches, drying oils and surfactant. From pentaerythritol receive softeners for PVC, synthetic oils. Attracts is a part of some cosmetic products. And sorbite found application in medicine as sucrose substitute.