Hundreds of years ago, the famous scientist of that time, Lully, who after his death was called the alchemist, managed to discover the indispensable diethyl ether. The formula, properties, boiling point, methods of obtaining substances will be described in detail in this article.
In the 13th century, the famous Spanish scientist Raymond Llull discovered the diethyl ether. Its properties were described in 1540 by no less famous scientist Paracelsus. In 1846, the ether was first tried to be used as anesthesia. The operation, conducted by an American doctor D. Warren using the vapors of this substance, was successful. The inventors of anesthesia are considered the dentist W. Morton and his mentor - a doctor and chemist C. Jackson.
Methods for obtaining ether in the 16th century were described by Valerius Cordus, a famous botanist and pharmacist originally from Kassel. From the beginning of the 18th century, an alcohol-ether mixture was used as a sedative - this was the proposal of Friedrich Hoffmann. Petersburg pharmacist Thomas Lovits in 1796 received pure diethyl ether, the formula of which, by the way, has two options (more on that later). But the principle of action of this substance on the human body was announced by the English physicist M. Faraday, after which in 1818 even a scientific article was published on this topic.
What is called a simple ether? This is an organic compound whose molecules consist of two hydrocarbon radicals and an oxygen atom. The most important simple, diethyl ether, the formula of which has the following form:
It is a colorless, transparent, very mobile volatile liquid with a peculiar smell and burning taste.
Under the influence of light, air, heat and moisture, the ether can decompose, forming toxic aldehydes, peroxides and ketones, which irritate the respiratory tract.
At a water temperature of 20 degrees it dissolves by 6.5%. It mixes well with fatty and essential oils, benzene and alcohol, regardless of the ratio.
The ether itself, however, like its vapors, is easily flammable. In a certain proportion with oxygen or air, diethyl ether vapors used for anesthesia are explosive.
All the chemical properties of ethers are characteristic of diethyl ether. So, let's deal with this issue in more detail. It is a rather inert substance. The main difference from esters is the lack of hydrolysis, although there are exceptions. In the cold, it does not interact with phosphorus chloride, metallic sodium, and many diluted mineral acids. Despite this, concentrated acids (sulfuric and hydroiodic), even at low temperatures, decompose these esters, and the heated metallic sodium breaks them down.
An ether with lone electron pairs interacts with a strong acid proton, resulting in an unstable oxonium compound:
- Acidolysis. Sulfuric and hydroiodic acids, as well as FeCl3 in acetic anhydride, are capable of cleaving ethers. The chemical reaction is as follows: CH3 – CH2 – O – CH2 – CH3 + HJ → CH3 – CH2 – OH + J – CH2 – CH3.
- The reaction of metallation, called the reaction Shorygin. Heated metallic sodium splits diethyl ether: C2H5 – O – C2H5 + 2Na → C2H5ONa + C2H5Na
- Relative chemical inertness does not prevent the esters from forming in the air to form peroxides, which often leads to explosions at the end of the distillation.
Diethyl ether: physical properties
A peculiar smell, low boiling point of ethers - evidence of weak intermolecular effects, and this indicates a low polarity and the absence of prerequisites for the formation of hydrogen bonds. In contrast to alcohols, esters have stronger electron-donating properties, which is confirmed by the value of the ionization potentials. The enhancement of these features is associated with the positive inductive effect of the group of atoms that are obtained from alkanes when the hydrogen atom is removed.
The ether is a low-level compound, less reactive than the alcohols. Remarkably dissolves most of the organic matter, so it is used as a solvent. An exception is not diethyl ether. Physical properties, as well as chemical, allow its use in medicine and in production.
Obtaining diethyl ether
Simple ethers do not occur in nature - they are obtained synthetically. Under the influence of acid catalysts on ethyl alcohol at elevated temperature, diethyl ether is obtained (the formula is given above). The easiest way to obtain this substance is by distillation of a mixture consisting of sulfuric acid and alcohol. To do this, it must be heated to 140-150 degrees Celsius. We need ethyl alcohol and sulfuric acid (in equal proportions), pipettes, test tubes and venting tubes.
So, after the equipment and reagents are prepared, you can start the experiment. In a test tube (it must be dry), pour 2-3 ml of a mixture of alcohol and acid and slowly heat it. As soon as boiling begins, the burner is removed and 5 to 10 drops of ethyl alcohol are added to the hot mixture using a pipette along the wall of the tube. The reaction proceeds as follows:
- CH3 — CH2 — OH (ethylsulfuric acid) + H2SO4 CH3 — CH2 — OSO3H + H2O;
- CH3 — CH2 — OSO3H + CH3 — CH3 — O;
- CH3 — CH2 — O — CH2 — CH3 (diethyl ether) + H2SO4.
About the formation of diethyl ether indicates the smell.
Use in medicine
Physicians use diethyl ether as a general anesthetic drug. The properties of this substance do not allow it to be used in operations where power tools are involved, since it is flammable and may explode when combined with air. Diethyl ether is widely distributed in surgery, where it is used for inhalation anesthesia. In dentistry, they are treated with dental root canals and carious places, thus preparing the oral cavity for filling.
Diethyl ether as fuel
The substance has a high cetane number (85-96), so it can be used as a starting fluid for gasoline and diesel engines. Due to the high variability and low flash points, diethyl ether is used as a component of the fuel mixture for exemplary diesel engines. It turns out that this substance is similar to ethanol.
Diethyl ether is recommended to be stored in dark colored bottles (carefully sealed) in a cool place, because it decomposes in the light, in heat and under the influence of moisture, resulting in toxic substances.