3-Pyridinecarbonitrile, 2-bromo-

Mercury is a highly toxic metal that is liquid at room temperature and volatile. Its chemical properties are unique. Among common metals, mercury is less active and difficult to react violently with acids and bases.
Mercury and oxygen can combine to form mercury oxide under heating conditions. This reaction requires moderate heating to promote the combination of the two to form a red mercury oxide powder.
Mercury can also react with some salt solutions. If mercury is placed in a silver nitrate solution, mercury can replace silver from the silver nitrate solution, because the metal activity of mercury is stronger than that of silver. This reaction shows that there is silver-white silver precipitation in the solution, and the color of the solution will also change.
Mercury is relatively low in the order of metal activity, which causes it to exist in a relatively stable state in chemical reactions. However, mercury and its compounds are many toxic, and they should be used and handled with extreme caution. Do not dispose of them at will, so as not to cause serious harm to the environment and human body. In ancient times, although the awareness of mercury's toxicity may not be as deep as it is today, it was also known that it has unique properties. Mercury was occasionally used in activities such as alchemy, but the ancients gradually noticed its possible adverse effects on the human body. When using mercury, whether ancient or modern, it should pay attention to its characteristics and potential hazards, and be handled and preserved in an appropriate way.

Mercury, or mercury, is a metallic element that is liquid at room temperature and has many unique physical properties.
It has good electrical conductivity, which makes it widely used in many fields of electrical equipment. Like the mercury switch in the past, the circuit is turned on and off by the flow of mercury, which is sensitive and convenient.
Mercury has a very high density of 13.59 grams per cubic centimeter, which is much denser than common metals such as iron and aluminum. This property makes it play an important role in specific measuring instruments, such as mercury barometers, which use the height of mercury to measure atmospheric pressure.
The melting point of mercury is -38.87 ° C and the boiling point is 356.6 ° C. The melting point is very low, so it is a liquid at room temperature and has good fluidity. And its boiling point is relatively moderate, which makes mercury excellent in the manufacture of thermometers, and can accurately indicate temperature changes through the principle of thermal expansion and contraction.
However, mercury also has its own harm. Mercury is volatile to a certain extent, and its vapor is toxic. If the human body inhales excessive mercury vapor, it will cause serious damage to the nervous system, kidneys, etc. And mercury will migrate and transform in the environment, and accumulate through the food chain, eventually endangering human health.
As for realgar, it is an arsenic sulfide mineral, its color is orange yellow, and it is brittle. When realgar is heated to a certain temperature, it will decompose into sulfur dioxide and arsenic, which is toxic. Although realgar is toxic, it has a place in the field of traditional Chinese medicine, with the functions of detoxification and insecticide, dryness and moisture to remove phlegm. At the same time, in folk culture, people often sprinkle realgar during the Dragon Boat Festival to repel snakes and insects, believing that it has the effect of warding off evil spirits and repelling plague. However, it should be noted that realgar cannot be taken internally at will, and improper use can easily lead to poisoning.

Mercury, or mercury, was widely used in ancient alchemy. In the era recorded in "Tiangong Kaiwu", mercury was mainly used in the field of alchemy for the following purposes:
First, it was used to refine medicinal pills. Ancient alchemists believed that by combining mercury with other minerals, herbs and other substances through a specific refining process, they could refine medicinal pills with magical effects. They believed that taking such medicinal pills could prolong life and even become immortals. In the works of many alchemists such as Ge Hong, the key role of mercury in the process of alchemy is mentioned. In the cauldron furnace of alchemy, mercury reacts with sulfur and other substances under high temperature and other conditions to form mercury sulfide and other substances. This reaction is regarded as a magical "change" by alchemists, hoping to obtain extraordinary medicinal pills.
Second, mercury also plays an important role in the smelting and processing of certain metals. Mercury can form amalgam with a variety of metals, and this property can be used to extract or purify certain metals. For example, in the smelting process of gold and silver, the addition of mercury can separate the gold and silver from other impurities to form amalgam, and then evaporate the mercury by heating, etc., so as to obtain relatively pure gold and silver.
Third, mercury is also used in some traditional processes. For example, when making gilt utensils in ancient times, gold and mercury were first made into gold amalgam and applied to the surface of the utensils. After heating, the mercury evaporated, and the gold was firmly attached to the utensils to form a beautiful gilt effect. This process demonstrates the ingenious use of mercury's unique physical and chemical properties in traditional processes.
However, with the development of the times and scientific progress, people have gradually realized the toxicity of mercury, and its application has also been restricted and regulated in many fields.

To prepare dihydroxypropyl methyl ether, there are various methods. First, propylene oxide and methanol are used as materials, and with the help of catalysts, an addition reaction is carried out. Among them, the appropriate catalyst is selected, such as alkali metal hydroxide or Lewis acid, which can promote the reaction to go forward and increase the yield. During the reaction, temperature control and pressure are also critical, usually the temperature is tens to hundreds of degrees Celsius, and the pressure is between several to tens of atmospheres, which can be adjusted according to the actual situation.
Second, propylene glycol and methanol can be used as raw materials and obtained by etherification. This reaction often requires acid catalysts, such as sulfuric acid or p-toluenesulfonic acid. When using acid catalysis, it is necessary to pay attention to the corrosion of equipment and the generation of side reactions. In the reaction, the reaction conditions, such as temperature, time and raw material ratio, should also be controlled to improve the purity and yield of the product.
Or, starting from propylene, propylene oxide can be oxidized first to obtain propylene oxide, and then reacted with methanol to obtain the target product. This path step is slightly complicated, but the raw material propylene has a wide source and may have advantages in cost. During the oxidation of propylene oxide, one step can be used as an oxidizing agent with air or oxygen, and the reaction is carried out in the presence of a catalyst. Subsequent reactions with methanol follow the above addition reaction method and carefully control the conditions.
All these methods have advantages and disadvantages. In the actual selection process, when considering the availability of raw materials, cost, equipment requirements and product quality, and other factors, we can carefully decide to achieve a good effect and a good preparation of dihydroxypropyl methyl ether.

The cultivation of crops depends on the fertility of the soil, the moisturization of the water, and the sunshine. When it comes to the hiding and transportation of rice, there are also many things that should be paid attention to.
In the room where the valley is hidden, you should seek high dryness to avoid the evil of dampness. Wet is easy to mildew and damage its quality. And it must be made dense to prevent the disease of rats and finches. Rats and finches eat, the amount of grain decreases and the quality also changes. Therefore, the protection of the hiding place should not be ignored.
As for the transportation of rice, the first thing is the safety of the journey. Road insurance is that the car is easy to tip, and the valley may be scattered, resulting in loss. Its journey is also appropriate, and it is easy to pass quickly, and it is easy to pass quickly. If it passes slowly, it is time-consuming and the
Furthermore, the carrier is also very important. The robustness of the carriage and the completeness of the waterproofing are indispensable. If there is a leak in the carriage, the grain will be drenched in the rain, and the wet grain will not survive, and it will eventually be waste grain.
Also, those who are in charge of hiding and transporting should have a sincere heart. Don't steal it for selfishness, and don't neglect it because of laziness. The grain is also the sky of the people, which is related to the lives of the people, and the foundation of the family and the country. The goodness of the Tibet and the stability of the transportation, the warehouse will be solid, and the people will be at peace; if the transportation in Tibet is not suitable, the grain will be damaged and the grain will be damaged, and the chaos will be feared. < Br >
Therefore, in the collection and transportation of grain, we should be cautious and pay attention to each section, so as to ensure that the grain is not damaged and people's livelihood is safe.