Thiophene-2,3-dicarboxylic acid

"Tiangong Kaiwu" has a saying: "Arsenic is the seedling of tin, and there is also silver ore in its place of growth. When tin is mined, the intermediate gas is not exhausted and the toxic fetus is formed." Arsenic, that is, arsenic, and 2,3-dichlorobenzoic acid, although not the same substance as arsenic, has its own uses in the world.
2,3-dichlorobenzoic acid is mainly used in organic synthesis. As a key intermediate in the preparation of dyes, it can participate in the construction of many dye molecules. Through a series of chemical reactions, cleverly combined with other organic compounds, it can produce colorful dyes with different properties, which add color to the printing and dyeing industry and make the fabric show a rich and diverse color.
In the field of medicine, 2,3-dichlorobenzoic acid also has important uses. Pharmaceutical chemists use it as a starting material to synthesize compounds with specific pharmacological activities through multi-step reactions. Or as an antibacterial drug to help resist the invasion of pathogens into the human body; or play a role in the development of anti-tumor drugs to contribute to the solution of cancer problems.
In terms of pesticides, compounds derived from 2,3-dichlorobenzoic acid can be made into high-efficiency pesticides. These pesticides can precisely act on harmful insects or weeds, inhibit their growth and reproduction, ensure the robust growth of crops, improve food production, and protect agricultural harvests. Although 2,3-dichlorobenzoic acid is not as well-known as arsenic, it shines brightly on the stage of organic synthesis, silently playing a key role in dyes, medicine, pesticides and many other industries, and has become an indispensable material for promoting the development of modern industry and agriculture.

In "Tiangong Kaiwu", Pi-2,3-dicarboxylic acid is a rare compound with unique physical properties. Let me describe it in detail for you.
Pi-2,3-dicarboxylic acid, under normal conditions, may be a crystalline solid, with a pure white color. It is like the first fall of frost and snow. The appearance is crystal clear, the luster is introverted, and there is no noise. Its texture is solid and brittle. If you hit it lightly, it will be fragile and crack into fine pieces, such as pearl and jade scattered.
In terms of melting point, Pi-2,3-dicarboxylic acid has its specific value. When the temperature gradually rises to a certain precise degree, about [X] degrees Celsius, its solid state gradually melts, turning into a flowing liquid state, just like ice and snow melting in the warm sun. The characteristic of this melting point is crucial for the identification and purification of this substance.
Furthermore, the solubility of this substance in water is also considerable. In water at room temperature, Pi-2,3-dicarboxylic acid is only slightly soluble, just like falling flowers in water, only slightly integrated into it, and most of it remains in the solid state. However, if the water temperature increases, its solubility will also gradually increase. For example, when the frozen soil is warm in spring, more matter dissolves into the water to form a uniform solution.
Its density is higher than that of common water, and it sinks directly when placed in water, such as a stone sinking abyss. Its density value is about [X] grams/cubic centimeter, which makes it different from many substances with similar densities.
Pi-2,3-dicarboxylic acid has a unique optical performance under light. Its crystal has good refraction and reflection ability to light, and it looks like a bright star, shining brightly.
In summary, Pi-2,3-dicarboxylic acid is unique in the forest of matter due to its unique physical properties. It is important for those who know, and has potential applications in chemical, pharmaceutical and other fields.

"Tiangong Kaiwu" contains: "Wuhexizhi, the properties of di- and trifid acids are really different." This Wuhexizhi, that is, Wuhexizhi, di- and trifid acids, is its specific nature.
Di- and trifid acids have peaceful properties, but they are different in the action of various things. Its taste is slightly acidic, clear but not strong. At room temperature, it is solid, the color is nearly white and slightly transparent, and the texture is firm and brittle. If you look carefully, you can see that its texture is fine.
When heated, it gradually melts, like ice disappearing in the warm sun, and its state changes from solid to liquid. And when heated to a specific degree, it can combine with other things and produce new substances, which has different properties. In water, it is slightly soluble, and the water liquid has a slightly light acid taste. This liquid can be in harmony with alkalis, and it looks like neutralization. It should be quick and clear. If it is tested with an indicator, the color change will be obvious.
When it encounters with metals, or it should be formed, such as the genus of iron and zinc, it can gradually erode the metal surface and produce new chemicals. Although this di- and tri- dissimilarity acid is tiny, its properties are different, and it can be used in the process of chemical application. It is also an essential quality for various industrial and medicinal uses. It is actually a wonder of creation.

"Tiangong Kaiwu" is a treasure of ancient scientific and technological books in our country, detailing many processes and technologies. The synthesis method of glutaric acid-2,3-dichloro substitutes is described in detail below.
First, glutaric acid is used as the starting material, and it is properly protected to prevent unnecessary reactions. Appropriate protective groups can be selected, such as converting the carboxyl group of glutaric acid into an ester group. Commonly used alcohols, such as methanol, ethanol, etc., are esterified under the catalysis of acidic catalysts such as sulfuric acid to generate dimethyl glutarate or diethyl glutarate. The key to this step lies in the precise control of the reaction conditions. The temperature and catalyst dosage need to be properly controlled to ensure that the reaction is efficient and there are few side reactions.
Second, the protected glutaric acid derivatives are halogenated. Using chlorine as a halogenated reagent, under the action of light or an initiator, chlorine gas is homogenized to generate chlorine radicals, which in turn undergoes radical substitution reactions with glutaric acid derivative molecules. When lighting, choose a suitable light source, light intensity and time; if an initiator is used, such as azobisisobutyronitrile (AIBN), its dosage should be controlled. In this process, due to the structural characteristics of glutaric acid derivatives, the hydrogen atoms at the 2,3-position are relatively active and are more easily replaced by chlorine atoms, resulting in the formation of the target product glutaric acid-2,3-dichloride precursor.
Third, remove the protective group. For the case of ester protection, it can be hydrolyzed under alkaline conditions. Commonly used bases such as sodium hydroxide aqueous solution are heated and refluxed to hydrolyze the ester group into carboxyl groups to obtain glutaric acid-2,3-dichloride. This step requires attention to the monitoring of the reaction process to prevent excessive hydrolysis or other side reactions.
Furthermore, there are other synthesis paths. Glutaric acid can be specially activated to further enhance the activity of hydrogen atoms at 2,3-position, and then directly react with halogenated reagents. For example, using some special Lewis acid catalysts to change the molecular electron cloud distribution of glutaric acid, and then react with chlorinated reagents such as phosphorus trichloride and phosphorus pentachloride, 2,3-position chlorination can be achieved. However, this method requires high reaction conditions and reagent purity, and special caution is required during operation.

Today, there is a product called 5-methyl-2,3-dichlorobenzoic acid. The quality of this product in the market is generally determined. Its lattice wave is often multi-terminal.
First, the quality of the product is very important. If the quality is good, it is in line with the high quality, and it must be high; on the contrary, if the quality is not enough, the quality is low. As the above-mentioned quality, it can be used for fine work and research, so the market is high.
Second, the supply and demand of the city also affects its quality. If the demand is low, and the supply is scarce, the price will rise; if the supply is low, there will be a lower price. For example, in a certain period, the demand for this product is greatly increased, but the quantity is limited, so the price will rise.
Third, the cost of construction in different places also has an impact. In different places, the cost of raw materials and manpower are different, and the complexity of the construction, whether it is first or not, all depend on the cost. The cost is low, and the cost is also easy to change.
Generally speaking, this is not the case in the city, and it varies from 100 gold per kilogram or from 100 gold to 100 gold per kilogram. However, this is a rough estimate, depending on the situation below.