What Are Amines?

Interpretation of amine: The product obtained by replacing one or more hydrogen atoms in an ammonia molecule with a hydrocarbon group is called an amine. According to the number of hydrogen atoms substituted in the amine molecule, the amine can be divided into primary, secondary, and tertiary amines; Hydrogen in the molecule is replaced by a hydrocarbon group. At the same time, amine can be regarded as a derivative of H in the ammonia molecule replaced by a hydrocarbon group. Amines are widely present in the biological world and have extremely important physiological and biological activities, such as Proteins, nucleic acids, many hormones, antibiotics, and alkaloids are all complex derivatives of amines. Most drugs used clinically are also amines or amine derivatives. Therefore, to master the properties and synthetic methods of amines is to study these complex natural products and Basis for better maintenance of human health.

According to the number of hydrogen substituted, it is divided into primary amine (primary amine) RNH ₂ , secondary amine (secondary amine) R ₂ NH,

Low temperature at normal temperature

Ammonolysis of halides

There is a lone pair of electrons on the ammonia or amine nitrogen, which acts as a nucleophile and undergoes a nucleophilic reaction with a haloalkane, and proceeds according to the SN2 mechanism. Many organic halides are treated with ammonia or ammonia to turn into amines:

X is halogen

RX + NH ₃ RNH ₃ + X-

RNH ₃ + X- RNH ₂ + H ₂ O + X-

Made with alcohol

The main synthetic method of amines is the alkylation of ammonia. Industrial use of alcohol and ammonia to synthesize organic amines:

ROH + NH ₃ RNH ₂ + H ₂ O

These reactions require the use of catalysts, special equipment, and additional purification, because the mixture of primary, secondary, and tertiary amines is obtained, and the selectivity of the reaction needs to be improved.

Amines are widely distributed in nature, most of which are produced by decarboxylation of amino acids. E.g:

Amine has a wide range of uses. The earliest development of the dye industry was based on aniline. Some amines are necessary for life support

The naming of simple amines, using amines as functional groups, is called an amine, and first writes the name of the hydroxyl group connected to the nitrogen atom, and then ends with the amine word; the primary amine of the diamine and polyamine, when its amino group is connected to the open chain When a hydroxyl group is directly connected to a benzene ring, it can be called a diamine or a triamine. ^[1]

The structure of the nitrogen atom in the amine is very similar to the nitrogen atom in the ammonia molecule, with three sp

Methylamine: CH ₃ NH ₂

Properties: Also known as monomethylamine, it is a colorless gas or liquid with ammonia odor at room temperature. It is easy to burn, and its vapor can form explosive mixture with air, and the explosion limit is 5% -21% (4.95% -20.75%). Relative density is 0.662, melting point is -93.5 ° C, boiling point is -6.3 to -6.7 ° C, -19.7 ° C (53.3kPa), -32.4 ° C (26.7kPa), -43.7 ° C (13.3kPa), -73.8 ° C (1.33kPa) , Decomposition temperature 250 , flash point (closed cup) 0 , auto-ignition point 430 , vapor pressure (25 ) 202.65Pa, critical temperature 156.9 , critical pressure 4.073kPa, refractive index 1.351. After liquefaction, the smoke body is more alkaline than ammonia. Soluble in water, ethanol and ether.

Ethylamine: CH ₃ CH ₂ NH ₂

Colorless liquid or gas with strong ammonia smell; vapor pressure 53.32kPa / 20 ; flash point: <-17.8 ; melting point -80.9 ; boiling point 16.6 ; solubility: soluble in water, ethanol, ether, etc .; density: Relative density (water = 1) 0.70; relative density (air = 1) 1.56; stability: stable; danger mark 4 (flammable gas), 14 (dangerous); main use: used in dye synthesis and as an extractant, Emulsifiers, pharmaceutical raw materials, reagents, etc.

I. Health hazards

Invasion: inhalation, ingestion, percutaneous absorption.

Health hazards: Exposure to ethylamine vapors can cause eye irritation, corneal damage and upper respiratory tract irritation. Liquid splashing into the eyes can cause severe low-level injuries; contaminated skin can cause burns. ^[1]

Second, emergency treatment and disposal methods

1. Emergency response to leakage

Quickly evacuate personnel from the leaked contaminated area to the upper reaches and isolate them to strictly restrict access. Cut off the fire. It is recommended that emergency handlers wear self-contained positive-pressure respirators and fire protective clothing. Cut off the source of the leak if possible. In the case of gas, use industrial coatings or absorbent / absorbents to cover the sewer near the leak point to prevent gas from entering. Reasonable ventilation to accelerate diffusion. Spray water is diluted and dissolved. Construct a large amount of waste water from dykes or pits. If possible, use the exhaust fan to send the cruel residual gas or leaked gas to the washing tower or the fume hood connected to the tower. The leaking container should be properly handled, and used after repairing and inspection. For liquids, absorb with sand, vermiculite or other inert materials. If there is a large amount of leakage, construct a dyke or dig pit for containment; cover it with foam to reduce steam disaster. Use explosion-proof pump to transfer to tanker or special collector, recycle or transport to waste disposal place for disposal. Storage tanks are best equipped with dilute acid spraying facilities.

Waste disposal method: Use controlled incineration. The nitrogen oxides discharged from the incinerator are removed by a scrubber or a high-temperature device.

2.Protective measures

Respiratory protection: When the concentration in the air exceeds the standard, wear a filtering gas mask (half-mask). It is recommended to wear an oxygen respirator or an air respirator for emergencies or evacuation.

Eye protection: Wear chemical safety protective glasses.

Body protection: Wear protective clothing.

Hand protection: Wear rubber gloves.

Others: Smoking, eating and drinking are strictly forbidden at the work site. After work, take a shower and change clothes.

3.First aid measures

Skin contact: Remove contaminated clothing immediately and rinse with plenty of running water for at least 15 minutes. Seek medical attention.

Eye contact: Raise the eyelids immediately and rinse thoroughly with plenty of running water or saline for at least 15 minutes. Seek medical attention.

Inhalation: Quickly leave the scene to fresh air. Keep your airways open. If breathing is difficult, give oxygen. If breathing stops, give artificial respiration immediately. Seek medical attention.

Ingestion: Rinse mouth with water and drink milk or egg white. Seek medical attention.

Fire extinguishing method: cut off the air source. If the gas source cannot be cut off immediately, the burning gas is not allowed to be extinguished. Spray water to cool the container, if possible, move the container from the fire to an open area. Fire extinguishing agent: mist water, alcohol-resistant foam, dry powder, carbon dioxide. ^[1]