Sulfuric acid has a historical name: vitriol oil. The study of acid began in ancient times, in its writings it was described: the Greek physician Dioscorides, the Roman naturalist Pliny the Elder, the Islamic alchemists Geber, Razi and Ibn Sina, and others. In Sumer there was a list of vitriol, which were classified by the color of the substance. Nowadays, the word "vitriol" combines the crystalline hydrates of divalent metal sulfates.
In the 17th century, the German-Dutch chemist Johann Glauber obtained sulfuric acid by burning sulfur with potassium nitrate (KNO3) in the presence of water vapor. In 1736, Joshua Ward (a pharmacist from London) used this method in production. This time can be considered a reference point when sulfuric acid began to be released on a large scale. Its formula (H2SO4), as is commonly believed, was established by the Swedish chemist Berzelius (1779–1848) a little later.
Berzelius, using alphabetic characters (denoting chemical elements) and lower numeric indices (indicating the number of atoms of a given species in a molecule), established that one molecule contains 1 sulfur atom (S), 2 hydrogen atoms (H) and 4 oxygen atoms (O ) Since that time, the qualitative and quantitative composition of the molecule has become known, that is, sulfuric acid is described in the language of chemistry.
The structural formula, which graphically shows the mutual arrangement of atoms in the molecule and the chemical bonds between them (they are usually denoted by lines), informs that there is a sulfur atom in the center of the molecule, which is connected by double bonds with two oxygen atoms. With the other two oxygen atoms, to each of which a hydrogen atom is attached, the same sulfur atom is connected by single bonds.
The properties
Sulfuric acid is a slightly yellowish or colorless, viscous liquid, soluble in water at any concentration. It is a strong mineral acid. Acid is highly aggressive towards metals (concentrated does not interact with iron without heating, but passivates it), rocks, animal tissues, or other materials. It is characterized by high hygroscopicity and pronounced properties of a strong oxidizing agent. At a temperature of 10.4 ° C, the acid solidifies. When heated to 300 ° C, almost 99% of the acid loses sulfuric anhydride (SO3).
Its properties vary depending on the concentration of its aqueous solution. There are common names for acid solutions. Diluted acid is considered up to 10%. Rechargeable - from 29 to 32%. At a concentration of less than 75% (as established in GOST 2184), it is called a tower. If the concentration is 98%, then it will be concentrated sulfuric acid. Formula (chemical or structural) in all cases remains unchanged.
When concentrated sulfuric anhydride is dissolved in sulfuric acid, oleum or fuming sulfuric acid is formed, its formula can be written as follows: H2S2O7. Pure acid (H2S2O7) is a solid with a melting point of 36 ° C. Hydration reactions of sulfuric acid are characterized by the release of heat in large quantities.
The diluted acid reacts with metals, reacting with which, it exhibits the properties of a strong oxidizing agent. In this case, sulfuric acid is restored, the formula of the formed substances containing the reduced (up to +4, 0 or -2) sulfur atom can be: SO2, S or H2S.
Reacts with non-metals, for example, carbon or sulfur:
2 H2SO4 + C → 2 SO2 + CO2 + 2 H2O
2 H2SO4 + S → 3 SO2 + 2 H2O
Reacts with sodium chloride:
H2SO4 + NaCl → NaHSO4 + HCl
It is characterized by the reaction of electrophilic substitution of a hydrogen atom attached to the benzene ring of an aromatic compound with a —SO3H group.
Getting
In 1831, the contact method for producing H2SO4 was patented, which is currently the main one. Today, most sulfuric acid is produced using this method. Sulfide ore (usually iron pyrite FeS2) is used as raw material, which is calcined in special furnaces, and calcined gas is formed. Since the gas temperature is 900 ° C, it is cooled with sulfuric acid with a concentration of 70%. Then the gas in the cyclone and the electrostatic precipitator is cleaned of dust, in the washing towers with acid with a concentration of 40 and 10% of catalytic poisons (As2O5 and fluorine), and the acid aerosol is wet on the electrostatic precipitators. Next, a calcining gas containing 9% sulfur dioxide (SO2) is dried and fed to the contact apparatus. After passing through 3 layers of a vanadium catalyst, SO2 is oxidized to SO3. Concentrated sulfuric acid is used to dissolve the resulting sulfuric anhydride. The formula for a solution of sulfuric anhydride (SO3) in anhydrous sulfuric acid is H2S2O7. In this form, oleum in steel tanks is transported to the consumer, where it is diluted to the desired concentration.
Application
Due to its various chemical properties, H2SO4 has a wide range of applications. In the production of acid itself, like an electrolyte in lead-acid batteries, for the manufacture of various cleaning products, it is also an important reagent in the chemical industry. It is also used in the manufacture of: alcohols, plastics, dyes, rubber, ether, adhesives, explosives, soaps and detergents, pharmaceuticals, pulp and paper, petroleum products.