Pyridine, 3-bromo-2,6-dichloro-

The compound formed by trivalent boron and divalent oxygen is called diboron trioxide. The chemical properties of this compound are particularly interesting.
Diboron trioxide is hygroscopic, placed in the air, can slowly absorb water and gradually form boric acid. Its reaction with water is mild and orderly, just like spring rain moisturizing, quietly transforming. Its reaction formula is: $B_ {2} O_ {3} + 3H_ {2} O = 2H_ {3} BO_ {3} $.
Furthermore, boron trioxide can react with bases to form borates. This reaction is like the combination of yin and yang, neutralizing acid and base. Taking sodium hydroxide as an example, its reaction formula is: $B_ {2} O_ {3} + 2NaOH = 2NaBO_ {2} + H_ {2} O $. In this reaction, diboron trioxide exhibits the characteristics of acidic oxides.
Diboron trioxide can co-melt with various metal oxides at high temperatures to form borate glass with special properties. This process is like a wonderful change in alchemy, giving glass unique optical and physical properties, such as good thermal and chemical stability, and is often used in the manufacture of special glasses.
In addition, diboron trioxide can also react with carbon, metals, etc. at high temperatures. If co-heating with carbon, elemental boron can be obtained, which is one of the important ways to obtain elemental boron. This reaction is like rebirth from fire, and boron is released from the compound and regains its freedom.
All these are important chemical properties of boron trioxide, which are indispensable in many fields such as chemical industry and materials.

"Mercury, also known as mercury, is a substance that flows but does not stagnate. It is volatile when heated, and it is heavy and can flow away on top of other substances." Mercury, that is, mercury, is a liquid metal. Under normal temperature and pressure, it shows a flowing state and appears to have no fixed shape.
The physical properties of mercury are specific. Its melting point is extremely low, only -38.87 ° C. Therefore, under normal temperature, mercury is in a liquid state and can flow at will, like water. The boiling point is 356.6 ° C. When heated, it is highly volatile and turns into mercury vapor, which drifts into the air. The density of mercury is extremely high, about 13.59g/cm ³, which is much heavier than that of ordinary liquids. This density allows mercury to flow on the surface of many objects without easily fusing with common things.
In addition, mercury has a metallic luster and shimmering silver light, which is quite eye-catching. Although it is liquid, it does not lose the characteristics of metal, such as good electrical conductivity. Mercury also has a certain surface tension. On a smooth surface, it can aggregate into a ball, which is like a round water silver bead, which is smart and beautiful.
However, mercury is toxic. If the volatile mercury vapor is inhaled by humans or directly comes into contact with the human body, it can cause serious damage to human health. Therefore, when using and handling mercury, it is necessary to exercise extreme caution and follow scientific methods to avoid the risk of poisoning.

"Tiangong Kaiwu" is a scientific and technological masterpiece written by Song Yingxing in the Ming Dynasty. There are many accounts of alum (the "alum" mentioned here is related to "dialum") and other things. Alum is widely used, and dialum is potassium aluminum sulfate. Its main uses can be discussed from the following aspects.
In the paper industry, dialum has played an important role. In ancient man-made paper, during the preparation of pulp and the forming process of paper, dialum can interact with the cellulose in the paper to help the paper better absorb ink or pigment, making writing and printing smoother. The handwriting and pattern are clear and long-lasting, and it is not easy to fade and smudge. It greatly improves the quality of paper and lays a good material foundation for cultural inheritance and dissemination.
In the field of food processing, dialum also has its uses. In ancient times, dialum was often added to make fried pasta such as fritters. It reacts with sodium bicarbonate to produce carbon dioxide gas, which makes the dough expand rapidly during the frying process, forming a loose and porous structure, making the fritters have a crispy taste and are deeply loved by the public.
In the printing and dyeing industry, dialum has a significant effect. During dyeing, dialum can be used as a mordant to enhance the bonding force between the dye and the fabric fibers, making the dye more firmly attached to the fabric. The dyeing is more uniform, the color is brighter, and it is not easy to fade after washing and sun exposure, ensuring the quality of printing and dyeing products and promoting the development of printing and dyeing processes.
In terms of water purification, dialum also contributes. Although the ancients did not have modern precision water purification technology, it is known that the aluminum hydroxide colloid produced by dissolving dialum in water can absorb suspended impurities in water, precipitate them, clarify turbid water, purify water quality to a certain extent, and meet the basic water needs of life and production.
It can be seen that dialum played an important role in many aspects of ancient papermaking, food processing, printing and dyeing, and water purification, and had a profound impact on social production and life at that time.

There are various methods for the synthesis of fuchdienyne compounds such as 3-acetylene-2,6-dienyne.
One is the formation of a reaction through carbon-carbon bonds. Alkynyl halides can be coupled with alkenyl halides under the action of suitable metal catalysts. For example, with a palladium catalyst, in the presence of a base, alkynyl bromide and alkenyl iodine are coupled. This is a classic coupling strategy, which can precisely form carbon-carbon bonds, so as to achieve the construction of the carbon skeleton of the target molecule. The advantage is that the reaction conditions are relatively mild, the selectivity is good, and the reaction parameters can be adjusted according to the substrate structure to achieve the ideal yield.
The second is the reaction with the help of organometallic reagents. For example, Grignard reagent or organolithium reagent reacts with a substrate containing suitable functional groups. The Grignard reagent is first prepared from alkenyl halide, and then reacts with alkynyl halide or alkynyl carbonyl compound, and then reacts with nucleophilic substitution or addition elimination to form a dienyne structure. This method is highly flexible and can modify the substrate in a variety of ways, only need to pay attention to the sensitivity of the reagent to water and air, and the operation needs to be carried out in an anhydrous and oxygen-free environment.
The third is the cyclization reaction strategy. Select a suitable linear precursor and construct the dienyne structure through intramolecular cyclization For example, chain-like compounds containing alkyne functional groups undergo intramolecular cyclization under thermal or photoinitiation to form specific dialkyne cyclic structures. This approach can build complex structures in one step, with high atomic economy, but strict requirements on substrate structure, and careful design of precursor molecular structures is required to promote cyclization reactions.
Synthesis of 3-acetylene-2,6-dienyne has advantages and disadvantages. In practical applications, the appropriate synthesis path needs to be weighed according to factors such as raw material availability, reaction conditions and purity requirements of target products.

When storing and transporting two-gas utensils, there are many people who should pay attention to them.
When storing and storing, the environment is the most appropriate. If it is in a humid place, the two-gas utensils are prone to rust, damage their quality and damage their use. Therefore, choose a dry and ventilated place to avoid the immersion of water and moisture, and the condensation of yin. And the two-gas ones are active or active. If they are hot, they will condensate when they are cold. Temperature control is also important. If the temperature is high, the gas will be prosperous, and the device will not expand, or there may be a risk of bursting; if the temperature is low, the gas will shrink, or its performance will be affected. If it is stored in a place, the temperature should be moderate, so that the two-gas can be settled in the device and keep it stable and unchanged.
As for transportation, its stability is the most critical. The two-gas device may be fragile, and it is easy to be damaged due to bumps and vibrations on the way. Therefore, when handling, handle it with care and do not collide. And on the vehicle, it needs to be properly fixed to prevent the shaking and swaying of the vehicle, causing the device to fall and be damaged. Furthermore, when transporting, it is also necessary to observe changes in the weather. Heavy rain, sand and other bad weather can damage the device. Rain is wet, sand is dust, and it is not good for the device. Therefore, in such weather, it is advisable to avoid it for a while and wait for the day to clear before transporting it.
In addition, people who store and transport should also have professional knowledge and caution. Knowing the nature of the two qi and understanding the characteristics of the device, so that you can pay attention to the details at every step, so that the two qi device is safe and intact during storage and transportation, so as to ensure smooth subsequent use.