Six chemical reactions that changed history
Also known as carbonyl ammonium reaction or non-enzymatic browning reaction, it refers to the reaction between amino compounds and carbonyl compounds, and is one of the main sources of food flavor.
The Maillard reaction is considered to be one of the most important chemical reactions that occur in food processing. It affects the quality characteristics of food, such as color, flavor, nutritional value, and physical-chemical properties of food ingredients.
Maillard reaction products (mainly containing melanoids, reduced ketones and heterocyclic compounds containing N, S, O) are the main sources of flavour in meat products. The anti-oxidant properties of Maillard reaction products (MRPs) are used To replace phenolic antioxidants is gradually attracting people's attention.
Originally refers to copper-tin alloys, and copper alloys other than brass and white copper are called bronzes, and they are often given the name of the first major additive element before the bronze name. Tin bronze has good casting performance, anti-friction performance and good mechanical properties, and is suitable for manufacturing bearings, worm gears, gears, etc.
Lead bronze is a widely used bearing material for modern engines and grinders. Aluminum bronze has high strength, good wear resistance and corrosion resistance, and is used for casting high load gears, bushings, marine propellers, etc.
Beryllium bronze and phosphor bronze have high elastic limit and good electrical conductivity, and are suitable for manufacturing precision springs and electrical contact components. Beryllium bronze is also used to manufacture non-sparking tools used in coal mines and oil depots.
Generally speaking, fermentation refers to a certain decomposition process of organisms to organic matter. Fermentation is a kind of biochemical reaction that humans came into contact with earlier. Nowadays, it is widely used in food industry, biology and chemical industry. It is also the basic process of biological engineering, that is, fermentation engineering.
Anaerobic respiration of microorganisms such as yeast and lactic acid bacteria is also called fermentation. Research on fermentation mechanism and process control in real life is continuing.
4. Saponification reaction
Saponification usually refers to the reaction of a base (usually a strong base) with an ester to produce an alcohol and a carboxylic acid salt, especially a fat and a base.
In a narrow sense, saponification is limited to the reaction of oils and fats mixed with sodium or potassium hydroxide to obtain the sodium / potassium salt of higher fatty acids and glycerol.
This reaction is a step in the process of making soap, hence the name. Its chemical reaction mechanism was discovered by French scientist Eugène Chevreul in 1823.
Is a chemical element, its chemical symbol is Si
Its scope of application is wide:
High purity single crystal silicon is an important semiconductor material.
Metal ceramics, important materials for space navigation.
Optical fiber communication, the latest modern communication means.
Silicone compound with excellent performance. For example, silicone plastic is an excellent waterproof coating material.
Silicon can increase the hardness of plant stems and increase the difficulty of feeding and digesting pests.
It is a chemical method for producing ammonia from nitrogen in the atmosphere.
Developed in the early 20th century, a chemical method for producing ammonia from nitrogen in the atmosphere. It is one of the most important inventions in chemical methods, because it enables the fixation of nitrogen in the atmosphere, which can also be used to produce nitrate for fertilizers (and explosives) by converting it into nitric acid.
Haber (F. Haber) proved in theoretical experiments how to maintain nitrogen from air and hydrogen from water at appropriate temperatures and pressures, and react with catalysts. Bosch (C. Bosch) also demonstrated how to implement this method on an industrial scale. The total reaction is 3H2 + N2 = 2NH3.