pyridine, 4-chloro-

4-Oxygen is the main use of the Tao, which is the matter of the pill and the pill.
The husband is in the pill of the pill, and 4-Oxygen can be used to attract and help the pills to blend, so as to form pills. In the ancient alchemy family, the belief that gold and stone can make people live, and 4-Oxygen can transform the nature of gold and stone, and make the nature of the pill more peaceful, or increase its effectiveness. For example, adding 4-Oxygen to the pill recipe of mercury can reduce its toxicity, promote its reaction, and make the pill easier to take and less harmful.
In the realm of gold, 4-Oxygen is also very useful. It can be used to treat common diseases. In case of cold and paralysis, 4-oxygen can pass the cold and remove the cold, so as to help the blood to move. Because 4-oxygen has the power to dredge, it can make the force speed up the disease. Another example is the treatment of abdominal pain, 4-oxygen can work with the spleen and stomach, promote digestion, and make Zhongjiao good. Its properties are harmonious and not correct, so it is liked by the family. And 4-oxygen is used externally, and it also has the effect of building muscle. If the skin is damaged and the skin is not healed, apply it with an ointment containing 4-oxygen, which can accelerate the healing of the mouth and reduce pain.
Therefore, 4-oxygen has an important position in the way of medicine, providing a powerful help for the ancients to explore the way of life and treatment.

Although "4-alkane" is not specifically described in "Tiangong Kaiwu", it is involved in the characteristics of various substances. The physical properties of alkanes can be explained in classical words by using relevant principles.
Alkanes are a class of hydrocarbons. Under normal temperature and pressure, low-carbon substances, such as methane, ethane, and propane, are mostly gaseous. Because of its weak intermolecular force, it is difficult to bind molecules, so it is gaseous and light and can float in the air.
If the carbon number increases slightly, to butane, pentane, etc., it may be liquid at room temperature. Because the molecules increase, the intermolecular van der Waals force increases, and the attractive force between molecules increases, causing substances to condense into liquid. Looking at its liquid state, it is fluid, and the surface tension is small. When poured, it is as smooth as oil.
As for alkanes with high carbon numbers, such as paraffin, they are solid under normal conditions. This is because the molecules are large and complex in structure, strong intermolecular forces, and the molecules are arranged tightly and orderly, so the texture is solid.
The color of alkanes is mostly colorless. Its taste is usually light or almost odorless. Its density is less than that of water. If placed in water, it will float on the surface of the water. Because of its loose molecular structure, the mass per unit volume is less than that of water.
Furthermore, alkanes have extremely low solubility in water and are almost insoluble. This is because the molecules are non-polar and water is polar. According to the principle of "similar miscibility", the two are difficult to dissolve. Ran alkanes are soluble in many non-polar organic solvents, such as benzene, carbon tetrachloride, etc., which can be uniformly dispersed and immiscibly miscible.

4-Alkanes have mild chemical properties. The structure of alkanes is connected by a single bond of carbon and carbon, and the valence of carbon is saturated, which is the basis for their stability.
Under normal conditions, it is inert to strong acids, strong bases, and strong oxidants. Common strong acids and bases such as sulfuric acid and sodium hydroxide coexist with them, making it difficult to react. With the strong oxidant of potassium permanganate, it is also difficult to oxidize it.
However, alkanes can also show an active side when exposed to high temperature, light, or catalysts. One is the combustion reaction. Alkanes can burn violently in sufficient oxygen, generating carbon dioxide and water, and releasing a lot of heat energy. For example, the reaction formula of methane combustion is: $CH_ {4} + 2O_ {2}\ stackrel {ignited }{=\!=\!=} CO_ {2} + 2H_ {2} O $, which provides great energy for human life and industrial production.
The second is the substitution reaction. Under light conditions, alkanes can be replaced with halogens (such as chlorine). Take methane and chlorine as an example. When lit, chlorine atoms gradually replace hydrogen atoms in methane to generate chloromethane, dichloromethane, trichloromethane and carbon tetrachloride in turn. For example, $CH_ {4} + Cl_ {2}\ stackrel {light }{=\!=\!=} CH_ {3} Cl + HCl $. This substitution reaction is widely used in the field of organic synthesis, and can be used to introduce halogen atoms to lay the foundation for subsequent organic reactions.
In general, the chemical properties of 4-alkanes are usually stable, but under specific conditions, reactions such as combustion and substitution can occur, playing an important role in the stage of organic chemistry.

4 - There is a long way to go to the synthesis method. In the study of "Tiangong Wuwu", it can be roughly described.
First, it is obtained by using water and carbon. Cloud: "When water meets red carbon, it is raw." This is the water and coal method. Water steaming passes through the coal of, the production is as follows: H ² O + C CO + H ². This reaction requires a high temperature, generally above 800 or 900 degrees, and a mixture of carbon monoxide can be obtained.
Second, it is reversed with gold acid. Such as dilute sulfuric acid, this specific reaction has not been reported in "Tiangong Materials", but the chemical properties of gold acid are involved. In case of dilute sulfuric acid, the reaction is strong, and the equation is: Zn + H ² SO= ZnSO+ H ² ↑. This inversion can be done under the room, and it is easy to set up. It only needs a container to hold dilute sulfuric acid, put it into the pellets, and collect it in a tube.
Third, the hydrolysis method. "Tiangong Materials", has not yet been mentioned, so it is not mentioned here. However, it can be seen from today's transformation that through water, water can decompose and oxidize, and its inversion: 2H ² O through 2H ² ↑ + O. A direct current source is required, and less sulfuric acid or oxidation is often added to the water to increase the resistance.
In addition, natural reforming can be obtained. The main component of natural reforming is methane, which is evaporated under high temperature and catalysis, and the reverse is as follows: CH + H2O + CO + 3H. This reaction is important in terms of engineering, and can generate a large amount of energy. However, high temperature and suitable catalysis are required.
Where this method has its own shortcomings, it can be used according to the ease of raw materials, or the ease of reaction.

The price of 4-bromopyridine in the market is usually between 500 and 3,000 gold per kilogram. The difference in this price depends on the purity of the quality, the quantity, and the different conditions of supply.
If the quality is pure and excellent, it is high-purity 4-bromopyridine, and its price is high, which can reach nearly 3,000 gold per kilogram. Cover high-purity things, it is difficult to make, and it consumes a lot of energy, so the value is high.
If the quality is slightly inferior and the purity is not excellent, the price may drop, and the price can be around 500 gold per kilogram. < Br >
And if there are many people who want it, and there is a shortage of supply, the price will also increase; conversely, if the supply exceeds the demand, the price will drop.
And the purchase volume also has an impact. If the purchase volume is huge, the merchant may offer a discount, and the price may be slightly reduced; if the purchase volume is small, the price will often remain unchanged. It is based on the market price of 4-bromopyridine, which is not fixed and often varies with various conditions.