Leaded gasoline contains tetraethyl lead, which is a toxic organometallic compound. Previously, it was used as an antiknock additive to fuel, and the purpose of its use was to increase the octane number.
The antiknock effect of this compound was discovered by American scientists at General Motors in 1921. The inventor Thomas Midgley, who was well aware of the harmful properties of lead in leaded gasoline, proposed replacing the word “lead” with the word “methyl” that was less understood by most people. Very little time passed, and the terrible consequences of this invention began to affect ordinary people working at General Motors. Mental disorders and related diseases began to take lives and irreversibly destroy the health of workers. However, most of the gasoline produced in the United States contained lead.
In the late forties and early fifties, they talked seriously about how harmful leaded gasoline was from all the stands, but because of the strong lobbying of its producers, they could not ban the production of this poison. Only in 1972, a ban on the use of tetraethyl lead was introduced, but several more years passed, until it was possible to completely displace it from the market. In 1986, the production of fuel containing tetraethyl lead was completely discontinued. The recovery of the American nation began: the lead content in the blood of the population decreased by 78% in 1994 compared with 1978. It was a victory of common sense over the notorious money.
Leaded gasoline was also widely used in the USSR. In the 80s of the last century, the abandonment of the use of tetraethyl lead began, which ended by 2003. On January 1, 2000, leaded gasoline was completely banned in the countries of the European Union. China abandoned the use of tetraethyl lead in 2001. Currently, most countries of the world do not produce this substance. In the UK they continue to produce a small amount of it, used as an additive in fuel for racing cars, but its production and use is disadvantageous due to the very high taxes levied by manufacturers. Tetraethyl lead is still used in several underdeveloped countries due to the low cost of its production. These countries include Afghanistan, Yemen, North Korea and several other states.
Today, throughout the civilized world, they are trying to use unleaded gasoline that does not contain tetraethyl lead, does not affect human health and does not violate the environment. To improve the quality of gasoline, various additives are introduced into it, and also the percentage of harmful substances (sulfur, aromatic hydrocarbons , etc.) in it is reduced. Unleaded gasoline must contain a permissible concentration of actual resins (not more than 5 mg per 100 cm3). Gasoline should also be divided by saturated vapor pressure and fractional composition. Its best and most economical type of car is considered A-98.
The composition of gasoline includes components that are produced as a result of a variety of technological processes. These include, for example, direct distillation of oil, catalytic cracking, catalytic reforming, hydrocracking of vacuum gas oil and other methods and technologies.
The composition of gasoline depends not only on the method of its production, but also on the brand. The higher the octane number, the higher the quality of gasoline. Gasoline A-95 has higher performance than gasoline A-92. Aviation gasolines have a higher octane rating than motor gasoline , due to the fact that the requirements for them are higher.