Views: 193 Author: Site Editor Publish Time: 2021-08-26 Origin: Site
Caffeine (CAS No.58-08-2) is a xanthine alkaloid compound, a central nervous stimulant that temporarily drives away drowsiness and restores energy, and is used clinically to treat neurosis and coma recovery. Caffeinated coffee, tea, soft drinks and energy drinks are very popular, so caffeine is also the most commonly used psychotropic drug in the world.
In North America, 90% of adults use caffeine on a daily basis. Many natural sources of caffeine also contain a variety of other xanthine alkaloids, including the cardiac stimulants theophylline and theobromine, as well as other substances such as tannins.
On October 27, 2017, the World Health Organization's International Agency for Research on Cancer published a preliminary list of carcinogens that reference caffeine as a Group 3 carcinogen, or a "not yet classifiable" carcinogen.
Caffeine is a plant alkaloid that can be found in many plants. As a natural pesticide, it paralyzes insects that ingest caffeinated plants. The most common caffeine-containing plants used by humans include coffee, tea and some cocoa. Other infrequent uses include the Paraguayan holly and guarana trees, which are generally used to make tea or energy drinks. The two aliases for caffeine: mateine and guarana factor evolved from these two plants.
The world's primary source of caffeine is the coffee bean (the seed of the coffee tree), which is also the raw material for coffee. The amount of caffeine in coffee depends greatly on the variety of beans and the method of coffee preparation, and even the amount of caffeine in coffee beans from the same tree can vary greatly. Generally speaking the amount of caffeine in a cup of coffee ranges from 40 mg in an espresso arabica to 100 mg in an espresso. Dark-roasted coffee generally has less caffeine than light-roasted coffee because the roasting reduces the amount of caffeine in the beans. Arabica coffee is usually lower in caffeine than medium fruit coffee. Coffee also contains traces of theophylline, but not theobromine.
Tea is another important source of caffeine, and the amount of caffeine per cup of tea is generally only half that of each cup of coffee, determined by the strength of the tea being made. Specific varieties of tea, such as black tea and oolong tea, have higher caffeine content than other teas. Tea contains a small amount of theobromine as well as a slightly higher amount of theophylline than coffee. The preparation of the tea has a great impact on the tea, but the colour of the tea is hardly indicative of the caffeine content. Japanese green tea contains far less caffeine than many black teas, such as Zheng Shan Xiao Zhu tea, which contains almost no caffeine.
Chocolate made from cocoa powder also contains a small amount of caffeine. Chocolate is a very weak stimulant, mainly due to the theobromine and theophylline it contains. A typical 28-gram bar of milk chocolate has about the same amount of caffeine as decaffeinated coffee.
Caffeine is also a common ingredient in soft drinks such as cola, which was originally made from cola nuts. A soft drink typically contains between 10 mg and 50 mg of caffeine in one bottle. Energy drinks, such as Red Bull, contain 50 milligrams of caffeine per bottle. The caffeine in these beverages comes from the original ingredients they use or from additives obtained from decaffeinated coffee, or it is chemically synthesized. Guarana, the basic ingredient in many energy drinks, contains high amounts of caffeine and small amounts of theobromine. Naturally occurring slow-release excipients contain small amounts of theophylline
3.The Basic Information
English name: Caffeine
Formal name: 1,3,7-Trimethylxanthine
More Alias: 1,3,7-Trimethylxanthine
Molecular formula： C8H10N4O2
Molecular weight: 194.19
4.Physical and Chemical Properties
Properties: white powder or white needle-like crystals. Odourless, bitter taste.
Melting point: 235-238℃, sublimation at 178℃. Under the pressure of 133Pa, it sublimates rapidly at 160-165℃.
Refractive index: 1.679
Solubility: Each gram of caffeine is soluble in 46 ml of water, 5.5 ml of hot water (80 ℃), 1.5 ml of boiling water, 66 ml of ethanol, 22 ml of hot ethanol (60 ℃), 50 ml of acetone, 5.5 ml of chloroform, 530 ml of ether, 100 ml of benzene, very soluble in pyrrole and tetrahydrofuran containing 4% water. Soluble in ethyl acetate, slightly soluble in petroleum ether. The solubility of the salts of this product in water increases in the order of benzoate; cinnamate; citrate; salicylic acid; hydrochloride of caffeine; sulfate; phosphate are all easily soluble in water or alcohol and decomposed into free base and acid.
5.The Storage Method
Non-toxic plastic bag or glass bottle sealed packaging. Store in a cool and dry place