1,3-dihydro-2h-benzimidazole-2-thion

"Tiangong Kaiwu" says: "Saltpeter, its nature is yin, sulfur, its nature is yang, and the two gods of yin and yang meet in a seamless and tolerable way. When it comes out, the character is captured, and the soul is scattered and the soul is powder." This is the matter of gunpowder.
The saltpeter, sulfur, and charcoal are the three main things of gunpowder. Gunpowder, its main uses, cover three things.
One, used in military. In ancient wars, weapons were still simple, but when gunpowder came out, it changed the pattern of warfare. In the words of artillery, fill it with gunpowder, and when it burns, it will fire stones and throw bullets, and strike the enemy from a distance. Its power is huge, it can break through city walls, destroy camps, and make the enemy terrified. Gunpowder and the like also rely on gunpowder to send projectiles. Compared with bows and arrows, it has a longer range and stronger lethality. It is also a weapon on the battlefield.
Second, used for celebrations. Every festive event, sparkling fireworks, this is also the power of gunpowder. Based on gunpowder, add all kinds of colors to make fireworks. When it is ignited, it is colorful and rises into the sky, or blooms like flowers, or flies like meteors, adding brilliance to the celebration, making the audience pleasing to the eye, and the joy is beyond words.
Third, used for production. In the matter of mining, gunpowder can crack rocks and open mountains, making ore easily available. Using gunpowder to blast, compared with people chiseling axes, is twice as effective. In the construction of roads, when encountering boulders and mountains, gunpowder can help them open, making traffic smooth and facilitating travel and goods circulation.
Gunpowder is a great achievement in ancient China, and it has a wide range of uses. It has made great contributions in military affairs, celebrations, and production, and has a profound impact on the development of the world.

Phosphorus nitrate is an important chemical substance. Its physical properties are quite unique, and today I will tell you in detail.
First of all, its color state is often in the form of colorless and transparent crystals, which are crystal clear and clear, just like jade beads. However, as seen in ordinary times, it is mostly yellowish or light brown due to impurities.
Second of all, its smell, pure phosphorus nitrate has no peculiar smell, but if it is slightly changed or mixed with other things, it occasionally has a slightly pungent smell, and it is slightly uncomfortable to smell.
Furthermore, the density of phosphorus nitrate is greater than that of water, and when placed in water, it sinks to the bottom, just like a stone falling into a deep pool. Its melting point is also fixed, about a certain temperature. When heated, it melts and turns into a flowing state. If candle wax is heated, it melts.
Solubility is also an important characteristic. Phosphorus nitrate is soluble in water and gradually melts in water, just like snow entering a warm pool to form a solution. This solution has good electrical conductivity because ions can move freely, just like fish swimming in water, which can conduct electrical energy.
In addition, phosphorus nitrate has deliquescence. In environments with high humidity, such as the rainy season in the south of the Yangtze River, it easily absorbs water vapor in the air, and the surface gradually moistens, like a thin layer of exposure. This is one end of its physical properties.
In addition, its appearance is delicate in texture, and it feels smooth to the touch, like fat. However, it needs to be treated with caution, because it is corrosive to a certain extent, if it is accidentally touched, it may hurt the skin, such as a sharp blade scratching the skin, which cannot be ignored.
In summary, the physical properties of phosphorus and nitrate, such as color, odor, density, melting point, solubility, deliquescence and texture, have their own characteristics, and are important in many fields such as chemical industry and agriculture. It needs to be carefully explored before it can be used effectively.

The author of "Tiangong Kaiwu" is a wonderful book of science and technology in ancient China, detailing all kinds of technological products. On the chemical properties of 1% 2C3-carbon dioxide-2H-naphthalene-thiophene-2-boronic acid, and in ancient Chinese.
Carbon dioxide is a colorless and odorless gas. Its temperature, heavier than air, soluble in water, carbonic acid. In case of alkali, it becomes a salt, such as with calcium hydroxide, the precipitation of calcium carbonate, this is a common method for testing carbon dioxide. In fire, carbon dioxide does not support combustion, but can be extinguished because of its oxygen barrier.
As for naphthothiophene, it has the structure of an aromatic ring, is stable, and is difficult to react with ordinary substances. Its aromatic properties are derived from the conjugated system. Naphthothiophene can react with halogenated hydrocarbons, aldosterones, etc. under specific conditions, such as high temperature and catalyst existence, and react with electrophilic substitution to obtain various derivatives.
Boric acid, a white crystalline solid, has a slightly acidic taste. Its aqueous solution is weakly acidic. Because boric acid in water does not ionize hydrogen ions by itself, it interacts with water and binds hydroxide to increase the concentration of hydrogen ions, so it is acidic. Boric acid has anti-corrosion properties and can be used for the preservation of medicine and food. And in the glass industry, it can increase the heat resistance and transparency of glass. It can form borate esters with alcohols, with a special aroma, and is commonly used in the preparation of fragrances.
These three have their own characteristics and are widely used in the fields of chemical industry, medicine, and materials. They are the cornerstone of chemistry and the main material of industry.

To prepare 1,3-diene-2H-naphthalenofuran-2-carboxylic acid, the method is as follows:
First take an appropriate amount of starting materials, and through ingenious reaction design, the molecular structure will gradually evolve to the target product. Or follow the classical path of organic synthesis, based on naphthalenofuran derivatives, modify and transform its functional groups through various chemical reactions.
During the reaction process, the reaction conditions, such as temperature, pressure, reaction time and the proportion of reactants, must be precisely controlled. The temperature can significantly affect the reaction rate and product selectivity; the adjustment of pressure is also related to whether the reaction can proceed smoothly. < Br >
In order to advance the reaction towards the formation of 1,3-diene-2H-naphthofuran-2-carboxylic acid, a suitable catalyst can be selected to reduce the activation energy of the reaction and speed up the reaction process. At the same time, pay attention to the pH of the reaction system, because acid-base conditions can play a key role in some reaction steps.
After the reaction is completed, it is necessary to pass through fine separation and purification steps to obtain high-purity target products. Extraction, distillation, column chromatography and other methods can be used to effectively separate the product from impurities.
This synthesis method requires profound knowledge and rich practical experience in organic synthesis to skillfully operate and make each reaction step smooth, and finally obtain the product of 1,3-diene-2H-naphthofuran-2-carboxylic acid. And during the experimental operation, it is necessary to follow safety regulations to ensure the smooth operation of the experiment and the safety of personnel.

There are many things that people should pay attention to when using sulfuric acid. First of all, it is strong in nature and highly corrosive, and it will be damaged immediately when it touches the skin and clothing. Therefore, when using it, it is necessary to strictly wear protective equipment, such as corrosion-resistant gloves, eyepieces, aprons, etc., to prevent it from splashing and injuring the body.
Furthermore, when diluting sulfuric acid, never pour water into sulfuric acid. When covering sulfuric acid into water, it will generate intense heat, causing droplets to splash, and it is dangerous. Slowly inject sulfuric acid into the water along the wall of the vessel, and keep stirring to dissipate the heat evenly.
When reacting with other substances with sulfuric acid, the reaction conditions and process need to be carefully reviewed. If it reacts with metal or produces flammable hydrogen, there must be no open flame around to prevent the risk of deflagration. And the reaction may generate harmful gases, when it is in a well-ventilated place, or a device for tail gas treatment should be set up to avoid polluting the environment and harming people.
As for the storage of sulfuric acid, it should be placed in a cool, dry and ventilated place, away from fire and heat sources, and stored separately from flammable and flammable materials, alkalis, metal powders, etc., and should not be mixed. The storage area should be equipped with suitable materials to contain leaks.
When using sulfuric acid, every step should be done with caution and in accordance with regulations, keeping in mind the importance of safety, so as to ensure that everything goes smoothly and there is no risk.