Introduction to Ethanol

Ethanol (ethanol), organic compound, molecular formula C2H6O, structural short formula CH3CH2OH or C2H5OH, commonly known as alcohol.

1. Introduction to ethanol

Ethanol is a flammable, volatile, colorless and transparent liquid at room temperature and pressure, low toxicity, the pure liquid is not directly drinkable;

has a special fragrance and slightly irritating; slightly sweet, and accompanied by a stimulating pungent taste.

Flammable, its vapor can form an explosive mixture with air, and can be miscible with water in any ratio. It is miscible with chloroform, ether, methanol, acetone and most other organic solvents.

Ethanol and methyl ether are isomers of each other.

Ethanol has a wide range of uses and can be used to make acetic acid, beverages, flavors, dyes, fuels, etc.

Ethanol is also commonly used in medical treatment as a disinfectant with a volume fraction of 70% to 75%,

and has a wide range of uses in defense chemicals, health care, food industry, and industrial and agricultural production.

2. Molecular structure of ethanol

C and O atoms are bonded, polar molecules with sp³ hybrid orbitals.

Ethanol molecule is composed of is composed of C, H, O three atoms (ethyl and hydroxyl two parts), can be seen as the product of a hydrogen atom in the ethane molecule replaced by hydroxyl,

can also be seen as a hydrogen atom in the water molecule replaced by ethyl.

3. Main types of ethanol

1, according to the raw materials used in production can be divided into starchy raw materials fermentation alcohol, molasses raw materials fermentation alcohol,

sulfite pulp waste fermentation production alcohol.

starchy raw materials fermentation alcohol (generally there are potatoes, cereals and wild plants containing starchy raw materials,

under the action of microorganisms will be starch hydrolysis into glucose, and then further fermentation by yeast to produce alcohol).

fermentation of alcohol from molasses raw materials (directly using the sugar in molasses, after dilution and sterilization and addition of some nutrient salts,fermentation by the action of yeast to produce alcohol)

Alcohol production by fermentation of sulfite pulp waste stream (using the six-carbon sugar contained in paper waste stream and fermenting it into alcohol by the action of yeast, with the main product being industrial alcohol. (Alcohol made from dilute acid hydrolysis of wood chips is also used).

2. According to the method of production, it can be divided into two categories: fermentation method and synthesis method.

3、According to the quality or nature of the product, it can be divided into high-purity alcohol, anhydrous alcohol, ordinary alcohol and denatured alcohol.

4, according to the product series (BG384-81) is divided into superior, first-class, second-class, third-class and fourth-class. Among them, first and second grade are equivalent to high purity alcohol and ordinary distilled alcohol.

The third level is equivalent to pharmaceutical alcohol and the fourth level is equivalent to industrial alcohol.

The new secondary standard was developed to meet the needs of different users and production, reduce waste in production and use, and promote the improvement of product quality.

4. Ethanol applications

(1) Disinfection supplies

Different concentrations of disinfectants.

Alcohol of 99.5% (v/v) or more is called anhydrous alcohol. Uses in biology:

The pigments in chloroplasts are soluble in the organic solvent anhydrous ethanol (or acetone), so the pigments in chloroplasts can be extracted with anhydrous ethanol.

95% alcohol is used to wipe UV lamps. This alcohol is commonly used in hospitals, but in the home it will only be used for cleaning camera lenses.

Alcohol of 70% to 75% is used for disinfection. This is because too high a concentration of alcohol will form a protective film on the surface of the bacteria, preventing it from entering the bacteria, making it difficult to kill them completely.

If the concentration of alcohol is too low, although the bacteria can enter the bacteria, but can not solidify the protein in its body, also can not kill the bacteria completely.

Among them, 75% alcohol has the best disinfection effect.

Alcohol of 40% to 50% can prevent bedsores. The back, waist and buttocks of patients who are bedridden for a long time can cause bedsores due to long-term pressure.

If a small amount of 40% to 50% alcohol is poured into the hands during massage and the patient is evenly massaged into the pressurized parts,

it can achieve the purpose of promoting local blood circulation and preventing the formation of bedsores.

Alcohol of 25% to 50% can be used to physically reduce fever. Patients with high fever can be wiped with it for the purpose of cooling their bodies.

Wiping the skin with alcohol causes the patient’s skin blood vessels to dilate, increasing the skin’s ability to dissipate heat, and the alcohol evaporates and absorbs heat,

causing the patient’s body surface temperature to decrease and symptoms to be relieved.

Note: The concentration of alcohol should not be too high, otherwise it may irritate the skin and absorb a large amount of water from the epidermis.

(2) Beverage products

Ethanol is the main component of wine (the amount is related to the type of wine).

Note: The ethanol in alcohol for everyday consumption is not ethanol added to it, but ethanol obtained by microbial fermentation,

and of course there will be related substances such as acetic acid or sugar depending on the type of microorganism used.

(3) Organic raw materials

Ethanol is also a basic organic chemical raw material, which can be used to make acetaldehyde, ether, ethyl acetate, ethylamine and other chemical raw materials,

as well as solvents, dyes, paints, detergents and other products.

(4) Automobile fuel

Ethanol can be used as a motor fuel, or mixed with gasoline as a blended fuel.

Ethanol from Yazin sweet sorghum in China makes up 10% of the gasoline. Ethanol gasoline has been sold in the United States for more than 20 years.

5 Ethanol safety measures

(1) Main hazards

Hazard: Ethanol is flammable and irritating. Its vapor and air can form an explosive mixture, which can cause combustion and explosion when exposed to open flame and high heat.

Contact with oxidizers can cause chemical reaction or combustion. In the fire, the heated container has the risk of explosion.

Its vapor is heavier than air, can be spread to a considerable distance at a lower level, and will catch fire and reignite when encountering an ignition source.

Health hazard: This product is a central nervous system depressant. It first causes excitation and then depression.

Route of ingestion: inhalation, ingestion, transdermal absorption.

Acute poisoning: Acute poisoning occurs mostly by oral administration.

It can generally be divided into four stages: excitation, hypnosis, anesthesia, and asphyxia. Patients enter the third or fourth stage with loss of consciousness,

dilated pupils, irregular breathing, shock, cardiac circulatory failure, and respiratory arrest.

Chronic effects: prolonged exposure to high concentrations of this product in production can cause symptoms of nasal, ocular, and mucosal irritation,

as well as headache, dizziness, fatigue, agitation, tremor, and nausea. Long-term alcohol abuse can cause polyneuropathy,

chronic gastritis, fatty liver, liver cirrhosis, myocardial damage, organic psychosis, etc. Long-term skin exposure can cause dryness, flaking, cracking, and dermatitis.

(2) Hazard prevention and control

Engineering control: closed operation, strengthen ventilation.

Respiratory protection: Generally no special protection is needed, filtered gas mask (half mask) can be worn for high concentration exposure.

Eye protection: Wear chemical safety glasses.

Body protection: Wear anti-static adhesive tape gas-protective clothing.

Hand protection: Wear general work protection gloves (rubber gloves).

Other protection: After work, shower and change clothes. Maintain good hygiene habits.