Methanol: Because it was first discovered in distilled wood, it is commonly known as "wood alcohol" or "wood essence", also known as hydroxymethane.

Property: A colorless liquid with an alcohol odor that is easily volatile.

Usage: Manufacturing formaldehyde and pesticides.

Ethanol: It has the aroma of alcohol and a stimulating spicy taste, with a slight sweetness. It is the main component of alcohol and is therefore commonly known as "alcohol".

Property: Colorless and transparent, volatile, flammable, non-conductive liquid.

Usage: Disinfection, basic industrial raw materials.

Propylene glycol

In 1779, it was first discovered by Scheer, and in 1823, it was recognized that oils and fats contain Chevreul, which means sweet in Greek and is therefore commonly known as glycerol.

Property: Colorless, odorless, sweet in taste, with a clear and viscous liquid appearance.

Usage: Manufacturing nitroglycerin, alkyd resin, and epoxy resin; Antifreeze and sweetener; Sweetener, cosmetics.

Phenol: Discovered in coal tar in 1834, it is commonly known as carbolic acid, and the first fame of phenol can be attributed to the famous British doctor Rist. Lister found that the majority of postoperative deaths in patients were caused by wound suppuration and infection. By chance, a dilute solution of phenol was used to spray surgical instruments and doctors' hands, resulting in a significant reduction in the patient's infection rate. This discovery makes phenol a powerful surgical disinfectant. Lister is also known as the "father of surgical disinfection" because of this.

Property: A colorless needle shaped crystal with a special odor, toxic at room temperature, slightly soluble in water, and easily soluble in organic solvents; When the temperature is above 65 degrees, it is miscible with water in any proportion. Corrosive, causing local protein denaturation.

Usage: Widely used in the manufacture of phenolic resins, epoxy resins, nylon fibers, plasticizers, developers, preservatives, insecticides, fungicides, dyes, pharmaceuticals, fragrances, and explosives.

formic acid

Formic acid: It exists in the secretions of bees, certain ants, and caterpillars, hence commonly known as formic acid.

Property: A colorless liquid with a pungent odor.

Usage: Organic chemical raw material.

Oxalic acid

Oxalic acid (oxalic acid): Oxalic acid is a metabolic product of living organisms, widely distributed in plants, animals, and fungi.

Properties: White powder, easily soluble in ethanol, soluble in water, slightly soluble in ether, insoluble in benzene and chloroform.

Usage: Used for manufacturing oxytetracycline, tetracycline, streptomycin, and borneol, as a bleaching agent and rust remover.

40% formaldehyde (formalin): formaldehyde is transliterated as "formalin", referring to a 40% formaldehyde solution.

Properties: Colorless and transparent, corrosive, highly volatile.

Usage: anti-corrosion, disinfection, bleaching.

Ethylene: It has been discovered in ancient China that placing fruits in houses burning incense candles can promote the ripening of harvested fruits. In the 19th century, Germans found that the leaves near the leaking gas pipe were easy to fall off. The first to discover that plant materials can produce a gas and have an impact on neighboring plants was Carzens, who discovered that the gas produced by oranges can ripen bananas mixed with them. It was not until 1934 that Gann first proved that plant tissues can indeed produce ethylene. Ethylene was officially identified as a plant hormone in 1966.

Property: A colorless gas with a slight odor, slightly lower density than air, difficult to dissolve in water, and easily soluble in organic solvents such as carbon tetrachloride.

Usage: Important organic chemical raw material, one of the basic raw materials in petrochemical industry, ripening agent, etc.

Acetylene (calcium carbide gas): Laboratory production of acetylene is made by adding water to calcium carbide, so acetylene is commonly known as calcium carbide gas. In 1836, the cousin of the famous British chemist Davy Humphry (1778-1829) and a chemistry professor at the Royal College of Cork in the Irish port city, Davy Edmund (1785-1857), heated charcoal and potassium carbonate to produce metallic potassium. He threw the residue (potassium carbide) into water, producing a gas that exploded. Analysis determined that the chemical composition of this gas was C and H (calculated using the atomic weight of carbon equal to 6 at the time), calling it "a new hydrogen dicarbode". This is because as early as 1825, his fellow Chinese chemist Faraday (Michael 1791-1867) also obtained a compound of carbon and hydrogen from the gas obtained by pressurized distillation of whale oil (used for illumination by Europeans at that time). The chemical composition of the compound was determined to be C and H, and it was named "hydrogen dicarbode". In fact, Faraday discovered benzene, and David Edmond discovered acetylene.

Property: Pure acetylene is a flammable gas with a colorless aromatic odor.

Usage: Used for lighting, welding, and cutting metals (acetylene oxygen flame), and also as a basic raw material for manufacturing acetaldehyde, acetic acid, benzene, synthetic rubber, synthetic fibers, etc.

Benzene: In 1834, German scientist E.E. Mitscherlich (1794-1863) obtained a liquid identical to Faraday's liquid by distilling a mixture of benzoic acid and lime, and named it benzene. After the establishment of correct molecular and atomic valence concepts in organic chemistry, French chemists such as C. F. Gerhardt (1815-1856) determined the relative molecular mass of benzene to be 78 and its molecular formula to be C6H6. The relative content of carbon in benzene molecules is so high that chemists are surprised. How to determine its structural formula? Chemists are in a dilemma: the high carbon to hydrogen ratio of benzene indicates that it is a highly unsaturated compound. But it does not possess the typical properties of unsaturated compounds that are prone to addition reactions.

Austrian chemist Joseph Loschmidt drew 121 cyclic chemical structures of benzene and other aromatic compounds in his 1861 book "Chemical Research". Kekule also read this book and mentioned in a letter to his students on January 4, 1862, that Roche's description of molecular structure was confusing. However, Lohemite drew the benzene ring as a circle.

German chemist Kekule was an imaginative scholar who proposed the important theory that carbon tetravalent and carbon atoms can be connected into chains. After analyzing a large number of experimental facts, he believed that the structure of benzene is a very stable "nucleus", with a very strong bond between six carbon atoms and a very compact arrangement. It can be connected to other carbon atoms to form aromatic compounds. So Kekule focused on studying the "nucleus" of these six carbon atoms. After proposing various open chain structures but rejecting them one by one due to their inconsistency with experimental results, he finally realized in 1865 that the closed chain form was the key to solving the structure of benzene molecules.

The process by which Kekule discovered the cyclic structure of benzene molecules has always been an interesting story in the history of chemistry. In 1890, at a conference celebrating the 25th anniversary of Kekule's discovery of the benzene ring structure held at the Berlin City Hall, he claimed that it came from a dream. That was when he was teaching at Ghent University in Belgium. One night, he dozed off in his study, and spinning carbon atoms appeared before his eyes. The long chain of carbon atoms coiled and coiled like a snake, and suddenly a snake grabbed its tail and spun incessantly. He woke up abruptly like an electric shock, organizing the hypothesis of the benzene ring structure, and was busy all night. Regarding this, Kekule said, "We should dream!... Then we can discover the truth... but do not declare our dreams before a sober rational examination." It should be pointed out that Kekule's ability to draw inspiration from dreams and successfully propose important structural theories was not accidental.

Property: A colorless and transparent liquid with carcinogenic toxicity and a strong aromatic odor. It is insoluble in water and easily soluble in organic solvents.

Usage: Benzene has the effect of reducing detonation and can be used as a gasoline additive and chemical raw material.