5-Bromo-2-chloropyridine-4-carbaldehyde

"Tiangong Kaiwu" has a saying: "Every mussel is pregnant with pearls, but it has no substance and is made of matter. He is small in shape and lives in the aquarium, devouring Hongduo, and his lifespan will not last forever. The mussel is wrapped in armor, and there is no gap to cast, that is, the abdomen can not be eliminated, so it is unique for a hundred years and a thousand years. The sincerity gradually comes, and it is formed into a pearl." Although this statement involves spirituality, it is also reasonable.
The pearl of the husband, also known as the real pearl, is formed by the elite of the mussel. The mussel lives in the shallow sea and sand, or in the freshwater lake. It is also a thing, and the outer shell is solid for self-consolidation, and the inner body is soft and spiritual. When foreign bodies such as sand and gravel invade, the mussel feels uncomfortable, so it is wrapped in layers of
The use of pearls is first and foremost the beauty of their decoration. The kings and nobles of ancient times all beaded their crowns, clothes, and palaces to show their honor and wealth. Its luster is warm and colorful, whether it is made into beads for neck ornaments, or inlaid on gold and silver objects, it all enhances its grandeur.
Secondly, pearls are used as medicine, and they also have special merits. "Compendium of Materia Medica" states: "Pearls are salty in taste, sweet and cold are non-toxic. Calm down and take a look; paint the face, making people moisturize and have a good color. Apply hands and feet to remove the skin from the reverse; drop phlegm, remove facial spots, and stop diarrhea; remove heat in children, calm the soul; stop white sperm, relieve acne and cure poison." It can be seen that it has a lot of effects in medical and health care.
Furthermore, pearls are of great significance in cultural etiquette. In wedding ceremonies, pearls are often used as a token, symbolizing the constancy of love and the happiness of marriage. At the time of sacrifice, pearls are also treasures offered to the gods, expressing the fear of God.
Therefore, pearls are used in decoration, medicine, culture and other fields, and are rare treasures in the world.

The synthesis method of carboxymethyl ether has been used in ancient times, and there are many methods, each with its own beauty.
One is to prepare dimethyl sulfate and sodium methoxide. When the two meet, in the environment of suitable temperature and pressure, the methyl group of dimethyl sulfate is very active, and it absorbs the oxygen atom of sodium methoxide to form the structure of methyl ether. In this process, it is necessary to pay attention to the proportion of materials. If there is too much dimethyl sulfate, the by-product will be heterogeneous; if there is too much sodium methoxide, it may also cause other side reactions. And the temperature and pressure of the reaction environment also have a great influence. If the temperature is high, the reaction speed will be high, and the side reactions will be easy to occur; if the temperature is low, the reaction will be slow and time-consuming.
Second, the method of dehydration of methanol is Before methanol is used in a specific catalyst, such as gamma-alumina, a molecule of water is removed from the heated molecules and polymerized to form methyl ether. The activity of the catalyst is the heaviest, and the reaction speed and selectivity are excellent if the activity is high. If the activity is low, the reaction is sluggish and the yield of methyl ether is not high. And the temperature control is very important. If it is too high, methanol is easy to crack into other substances, and if it is too low, the dehydration reaction is difficult to start.
Third, methyl ether is directly produced from synthesis gas. For synthesis gas, a mixture of carbon monoxide and hydrogen is also used. Under the bifunctional catalyst, carbon monoxide is hydrogenated to form methanol, and methanol is dehydrated to form methyl ether. This process is achieved in one step, eliminating many steps, but it requires strict catalyst requirements. The catalyst needs to have the ability to dehydrate synthesis gas to methanol and methanol, and can resist poisoning and sintering to maintain long-term activity. In the reaction, the ratio of synthesis gas is also critical, and the discomfort of the hydrogen-carbon ratio will affect the formation of methyl ether or cause carbon deposition.
This method has its own strengths and weaknesses. When choosing a method, it depends on the availability of raw materials, the cost, the availability of equipment, and environmental protection requirements.

In today's city, merchants sell things, and the price varies according to time, place, and quality. As for the market price of turtles, it also follows this law, and it cannot be said in a word.
When the husband is in different seasons, the supply and demand of turtles are different. In spring, all things recover, turtles are dormant at the beginning, the supply of the city is small, and diners are eager for fresh food, and there are many people who want it, and the price rises. In summer, turtles are active, fishing is easy, the supply increases, and the price may drop slightly. In autumn, the weather is getting cooler, and the turtles are stored for energy over the winter. The meat is plump, and everyone is good. Demand rises and the price also rises. In winter, more turtles enter the sting, which is difficult to catch. The market is scarce, and the price is often high.
The land is very different from the north and the south, and the price is also different. The southern water town, where rivers and wetlands intersect, where turtles live and reproduce, produces turtles abundantly, and its price may be more affordable. There is less water in the north, and the turtles depend on foreign transportation. In addition to the cost of transportation and preservation, the price must be higher than that in the south.
And the quality, wild and domestic, the price is very different. Wild turtles, born in nature, eat natural bait, grow slowly, the meat is firm, the taste is mellow, and the quantity is thin. They are cherished by diners and are expensive. Domestic breeders, bred with feed, grow quickly and produce large yields. Although they also have the taste of turtles, they are inferior to wild ones, and the price is also low.
And the size of the market, the prosperity of the location, also has an impact on the price of turtle. In the big market, there are frequent transactions, fierce competition, and the price may be relatively public. And small shops in remote cities, the supply is limited, or the price may be raised because of it.
Therefore, if you want to know the market price of turtle, when you judge the situation, observe its origin and quality, and analyze it comprehensively, you can get the actual price. It cannot be generalized, and you must study its situation carefully to get it.

Lead and mercury, the beauty of hardware, heaven and earth to the essence. Lead is heavy and solid, its color is blue and black, and it has gold in it. If it gets fire, it flows, and if it encounters yin, it will knot, and it can change all things. It is the master of hardware. Mercury is smart, its color is bright, like water like silver. If you see fire, you will fly, and if you get lead, you will stay. It can subdue all kinds of medicines and is the foundation of returning pills.
Lead is heavy and dense, and it is solid at room temperature. Its color is dark like black iron, but it contains the essence of purity. If it is thrown into fire, it will melt into liquid. If it encounters with yin, it will condense again as before. Its nature is stable and not easy to evaporate, so it can be stored in utensils for a long time. And lead can be combined with various metals, changing its quality, making other things tough and durable.
Mercury flows like water, but it also contains the luster of silver, which is extremely flexible and lively. When heated, it turns into steam and rises away, which is elusive. However, although mercury is impatient, if it is combined with lead, it can be used as a phase. Mercury can be incorporated into various medicines, leading its medicinal power to the place of illness, and can also make various medicines and play a strange role.
In the past, lead and mercury were used for alchemy. The combination of lead and mercury is an extraordinary ratio, which is actually the combination of yin and yang, and the combination of rigidity and softness. Lead is yang and mercury is yin, and the two are sympathetic, so they can become pills. The nature of lead and mercury is also the wonder of the creation of heaven and earth. Among the hardware, it is only good at its ability, and it is valued by the practitioners of alchemy. It is all because of its ability to seize the creation of heaven and earth, return the original and return the yuan, and achieve extraordinary power. The solidity of lead, the agility of mercury, one static and one moving, complement each other, and are of supreme use in the path of alchemy. Those who are not proficient cannot understand its mysteries.

Methyl ether is an organic compound. Its chemical formula is $C_ {2} H_ {6} O $, which can also be written as $CH_ {3} OCH_ {3} $. This substance has the following chemical properties:
** I. Flammability **
Methyl ether is highly flammable and can react violently with oxygen in the air, releasing a large amount of heat, carbon dioxide and water. The chemical equation for combustion is: $C_ {2} H_ {6} O + 3O_ {2}\ stackrel {ignited }{=\!=\!=} 2CO_ {2} + 3H_ {2} O $. Due to its combustion characteristics, methyl ether is often used as a fuel, such as partially replacing liquefied gas in civilian gas fields, or as a vehicle fuel. Its combustion is relatively clean and produces less pollutants than traditional fuels.
** Second, the reaction with strong acids **
Methyl ether can react with strong acids, such as hydroiodic acid (HI). In this reaction, the ether bond of the methyl ether will break, resulting in iodomethane and methanol. The chemical equation is: $CH_ {3} OCH_ {3} + HI\ longrightarrow CH_ {3} I + CH_ {3} OH $. If there is an excess of hydroiodic acid, the generated methanol will further react with hydroiodic acid, eventually generating iodomethane. This reaction reflects the sensitivity of methyl ether to strong acids. In organic synthesis, this reaction can be used to modify the structure of methyl ether and prepare other organic compounds.
** III. Oxidation Reaction (Non-Combustion) **
Under specific catalysts and conditions, methyl ether can undergo selective oxidation reactions. For example, with some metal oxides as catalysts, methyl ether can be oxidized to formaldehyde and other products. This reaction is of great significance in organic chemical production, providing a new path for the preparation of important chemical raw materials such as formaldehyde. Compared with traditional formaldehyde production methods, if this methyl ether oxidation process can be optimized, more efficient and environmentally friendly production may be achieved. < Br >
** IV. Nucleophilic Substitution Reaction **
Hydrogen atoms on the methyl group of methyl ether can undergo nucleophilic substitution reaction under appropriate reagents and conditions. When nucleophilic reagents exist, nucleophilic reagents will attack the hydrogen on the methyl group, thereby causing the methyl ether molecule to undergo a substitution reaction to generate new organic compounds. This property can be used in organic synthesis to construct more complex organic molecular structures and expand the variety and use of organic compounds.