What is Alcohol?
In chemistry, any substance that contains a hydroxyl group (-OH) in its chemical formula is considered an alcohol. Alcohol is derived from hydrocarbons, where each molecule consists of a combination of hydrogen and carbon atoms. Ultimately, a hydroxyl group (OH) replaces a hydrogen atom, and depending on the number of hydroxyl groups, alcohols are referred to as either mono- or multi-valent.
A) Methyl Alcohol or Methanol
The simplest alcohol is methyl alcohol, which is a monovalent alcohol. Methyl alcohol is obtained by distilling wood and is thus also known as wood alcohol. Methyl alcohol is a colorless liquid that boils at 66°C, burns with a faint blue flame, and when mixed with water, its volume decreases and it generates heat.
Uses of Methyl Alcohol: It is used in the paint industry. It is also a strong poison; ingesting 8 to 10 grams of it can cause digestive disturbances and often blindness, leading to death.
B) Ethyl Alcohol
Ethyl alcohol, or ethanol, is a first-type alcohol. There are also other types of alcohol such as divalent and trivalent alcohols, for example, antifreeze is considered a divalent alcohol (or saturated di-alcohol), and glycerin is a trivalent alcohol (or saturated tri-alcohol).
Ethanol naturally exists in very small amounts in bread (0.5%), in the human brain, and in plants. In addition to yeast and some bacteria, the human body also produces a significant amount of alcohol. In most cases, this production is due to the microorganisms in the human intestine.
Properties of Ethyl Alcohol
Ethyl alcohol boils at 78.3°C and melts at -114°C. Absolute alcohol is a colorless, highly flammable liquid with a distinctive odor, and at low temperatures, it first becomes viscous and then freezes like glass.
Contrary to some misconceptions, alcohol does not have a stimulating effect on the body’s organs; rather, its effect is sedative, meaning it weakens bodily functions and reduces accuracy in performing various behaviors. In scientific texts, alcohol is categorized with other sedatives like ether and so on.
In any case, all alcoholic beverages contain some alcohol, and any sedative effects resulting from alcoholic beverages are due to this substance. The degree of this sedation, which we refer to as “intoxication,” depends on the alcohol content in such beverages. When a person drinks some alcohol, about 15% is immediately absorbed into the blood through the stomach lining, and the rest enters the intestines. Some may also be expelled through exhalation or urine, but the majority remains in the body, where it gradually oxidizes into carbon dioxide and water without requiring digestion.
The liver can oxidize 8 grams of alcohol per hour. Larger quantities appear in the bloodstream, but concentrations less than 0.05% do not cause any symptoms. Symptoms such as loss of physical balance and impaired vision appear when the concentration exceeds 0.05%.
At concentrations above 0.25%, distinct symptoms appear. If the concentration reaches 1% in the blood, respiratory and cardiac disturbances can occur, and ultimately death. However, the lethal dose varies by individual.
Uses of Alcohol:
Alcohol is one of the most widely used chemicals in processes such as synthesis, isolation, and production. In industry, alcohol is used for making varnish, aniline dyes, and medicines. It is also used in laboratories as a fuel, though using it for this purpose is not economical.
The alcohol used in industry is chemically identical to medicinal alcohol, and both are ethanol. Alcohol is the best organic solvent, which is why it has wide applications in laboratories and the pharmaceutical industry. It is also used to prevent microbial growth in pharmaceutical products, for making tablet coatings, and as a disinfectant.
In medicine, alcohol is used to disinfect medical tools and equipment. It also helps preserve anatomical specimens from decay and infection. Alcohol is also widely used in the production of perfumes and cosmetics.
The most important point is that alcohol at a concentration of 70% has disinfecting power.
