2-BROMOPYRIDINE-5-CARBALDEHYDE

Mercury dicyanide is a toxic drug, and its physical properties are particularly observable.
Mercury dicyanide is a white crystalline powder under normal conditions, with a fine and uniform quality. It feels smooth to the touch and has a slight luster under light, but it is ordinary on the surface, and it is difficult to hide its internal danger. The melting point is quite high, about 320 degrees Celsius. When heated to this temperature, it melts into a liquid state, which is due to the strong intermolecular force.
Furthermore, mercury dicyanide is slightly soluble in water. When dissolved, its molecules interact with water molecules, but the solubility is limited. In organic solvents, it is only slightly soluble. This solubility is closely related to the molecular structure, and the characteristics of its molecular polarity make it behave differently in different solvents.
Looking at its density, it is heavier than ordinary substances. When placed in the hand, it can feel its heavy state, which is determined by its atomic weight and crystal structure. And mercury dicyanide powder is very easy to fly, drifting in the air, and it is easy to inhale without paying attention. This is a major hazard.
And because it is highly toxic, it needs to be used and stored with extreme caution. Once touched, eaten or inhaled, it can endanger life. Its toxicology acts on human cells and destroys normal physiological functions, so it must not be ignored because of its normal physical properties. In the laboratory or industrial production, it is necessary to operate in strict accordance with regulations to prevent accidents.

Mercury, commonly known as mercury, is a liquid metal with many unique chemical properties.
Mercury is chemically active and can quickly combine with sulfur at room temperature to form mercury sulfide. When the two meet, it is like yin and yang sympathetic, and it becomes a new substance in an instant. Mercury sulfide is stable in nature and has a vermilion color. In ancient times, it was often used in alchemy and pigment production.
Mercury can also form alloys with various metals. This alloy is called amalgam. If it meets gold, it can form gold amalgam, and ancient people often used this method to extract gold. This process is like gold being "swallowed" by mercury, and the two fuse seamlessly.
Mercury can react with oxygen under heating conditions to form mercury oxide. This reaction requires a moderate heat, just as the heat is controlled by the subtlety of alchemy. Mercury oxide can be decomposed into mercury and oxygen when heated, showing a wonderful reversible change.
Although mercury is a metal, it is highly volatile. In the air, it evaporates silently, as if concealing its body. Its vapor is toxic, and if inhaled inadvertently, it can cause damage to the human viscera and dizziness.
In addition, there are many types of mercury compounds with different properties. Such as mercury chloride, which is highly corrosive and toxic, just like a hidden blade. Mercury sulfide is relatively stable and has a bright color, which is indispensable in Danqing painting.
Mercury's chemical properties are complex and changeable, with both active and volatile properties. In the cognition and application of the ancients, it was not only a wonder for alchemy and pharmaceuticals, but also needed to be treated with caution because of its toxicity. Its many characteristics are like a double-edged sword bestowed by nature. If used properly, it will benefit, and if used inadvertently, it will be a disaster.

2-%E6%BA%B4%E5%90%A1%E5%95%B6, 5-%E7%94%B2%E9%86%9B, are all chemical substances. 5-%E7%94%B2%E9%86%9B, there are many common synthesis methods, and each has its own ingenuity.
First, it is obtained by dehalogenation of halogenated hydrocarbons. When the halogenated hydrocarbon encounters an alcohol solution of a strong base, when heated, the halogen atom and the hydrogen atom on the orthocarbon are removed in the form of hydrogen halide to form an olefin. For example, bromoethane coheats with an alcohol solution of potassium hydroxide, and the bromine atom and the hydrogen atom of the orthocarbon leave to form ethylene. This reaction follows the Chaytsev rule and mainly produces olefins with more substituents on double-bonded carbons.
Second, alcohol dehydration can also be prepared. Under the action of dehydrating agents such as concentrated sulfuric acid, alcohol is heated to remove a molecule of water to form an ol For example, ethanol is dehydrated to form ethylene at 170 ° C under the catalysis of concentrated sulfuric acid. This process requires precise control of temperature. If the temperature is 140 ° C, the intermolecular dehydration of ethanol will produce ether instead of ethylene.
Third, alkynes can be partially hydrogenated. Catalytic hydrogenation of alkynes with a lindela catalyst can selectively add one molecule of hydrogen to alkynes to form olefins. If acetylene is hydrogenated under the action of a lindela catalyst, ethylene can be obtained. This catalyst can keep the reaction in the olefin stage without excessive hydrogenation to alkanes.
Fourth, it can be obtained by dehalogenation of o-dihalides. The o-dihalides react with metals such as zinc powder, and the halogen atoms are captured by the metals to form olefins. For example, 1,2-dibromoethane reacts with zinc powder to remove bromine atoms to produce ethylene.
The synthesis of 5-%E7%94%B2%E9%86%9B, according to the availability of raw materials, the difficulty of reaction conditions, the purity of the product and other factors, choose the appropriate method. The various synthesis methods, each showing the delicacy of chemistry, are the cornerstone of organic synthesis.

It is reported in "Tiangong Kaiwu" that gallops are produced by insects and are born in salt-skinned wood. This salt-skinned wood has leaves like toons, small flowers in July, slightly white, strong like jujube, turquoise, and red when it matures in September. Gallops parasitize on its trees, so there are traces of gallops in the places where salt-skinned wood grows.
Salt-skinned wood is mostly born in sparse forests and shrubs in mountains and hills, and is distributed in many places in our country. For example, Shaanxi, Sichuan, Guizhou, Yunnan, Hubei, Hunan, Guangdong, Guangxi and other places are common growth areas. The climate and soil conditions in these areas are suitable for the growth of salt-skinned wood, thus providing a good parasitic environment for gallops, so that gallops can be produced in such areas.
Gallnut has a wide range of uses. In the field of medicine, it has the functions of astringent hemostasis, astringent intestines and diarrhea, astringent lungs and fire reduction. Doctors often use it as medicine to treat a variety of diseases. In the industrial field, gallnut is rich in tannins and can be used in tanning, printing and dyeing, ink making and other industries. It is an important raw material for industrial production. And in the chemical industry, it is also an important raw material for many chemical products and has a wide range of uses. In short, in the above-mentioned salt skin wood growth and distribution areas, gallnut has important applications.

"All pearls must give birth to the belly of a clam, reflecting the moon to form a fetus, and it lasts for the longest time, which is a treasure." The pregnant pearl of a clam requires warm and moist water, a quiet environment, and no foreign body intrusion to form a pearl.
Now on the two-gilled bighead carp, the storage conditions of gall. The gall is formed by the double aphid parasitizing on trees such as salt skin wood. Its storage is quite exquisite. It needs to choose a dry and ventilated place to prevent moisture and rot. Because it is rich in tannins, it is easy to mold in case of moisture, resulting in damage to its quality.
The place of storage should be protected from direct sunlight. When exposed to sunlight, the composition of gallnut may change, reducing its medicinal or industrial effect. Furthermore, it should be isolated from odors. Gallnut has adsorption properties, is easy to dye odors, and damages its original taste and effectiveness.
Choose from containers, preferably pottery urns and wooden boxes. The pottery urn can keep its internal environment stable, and the wooden box also has certain moisture-proof and breathable properties. Do not use metal containers to prevent chemical reactions between tannins and metals, which will damage the quality of gallnut. In this way, proper storage will ensure that the effectiveness of gallnut will not be reduced for a long time, ready to be used.