5 Bromo 2 Iodophenol

In "Tiangong Kaiwu", it is recorded that arsenic, or letter stone, has the following main uses.
First, it is used in the field of medicine. In ancient medical texts, arsenic can be used as medicine to treat some diseases after being specially processed. Traditional Chinese medicine believes that arsenic has the effects of eroding sores and removing rot, killing insects, robbing phlegm, and cutting malaria. For example, when treating some surgical diseases such as sores and scrofula, the appropriate use of arsenic preparations can remove necrotic tissues and promote the growth of new meat with the help of its corrosive power. However, arsenic is highly toxic, and the dosage needs to be strictly controlled. If it is not careful, it will endanger life. Therefore, doctors are extremely cautious when using it.
Second, in agriculture, arsenic can be used as a pesticide. Due to its toxicity, it can drive away or kill some pests that harm crops, protect crops from pests, and ensure grain harvests. However, due to its greater potential harm to the environment and humans and animals, with the development of modern pesticides, such uses have gradually been phased out.
Third, it also had certain uses in the ancient metallurgical industry. Arsenic is sometimes used in some metal smelting processes. It can be used as an additive to affect the properties of metals, such as improving certain properties of metals to make them more suitable for specific use needs. However, this use has also gradually decreased with the advancement of metallurgical technology.
In short, although arsenic has certain uses, it is highly toxic and requires extreme caution when used. In modern society, the use of arsenic is subject to strict regulations and supervision.

Saltpeter, white as frost and snow, is brittle and easily broken. The taste is extremely bitter and salty, and the nature is cold. Placed on the fire, it will quickly ignite, and it will make an explosive sound. The fire is very fierce, like the wrath of thunder.
Sulfur, yellow as gold in color, has a special odor, and is greasy to touch. It is warm in nature and flammable. When burned, the flame is blue-purple, and it is accompanied by pungent smoke, which can smoke the eyes and nose, causing discomfort.
Charcoal, black and light in color, rough in surface, porous and loose. It is warm in nature and burns slowly. Although the fire is not hot, it will last for a long time and has a red-hot light. If properly stored, it can be hidden for a long time.
Of these three, saltpeter is known for its cold and explosive properties; sulfur is known for its warm, smelly and flammable properties; and charcoal is known for its warm, light, porous and long-lasting combustion properties. Each has unique physical properties and plays a different role in various uses.

Borax is a common mineral with unique chemical properties. The main component of borax is sodium tetraborate, which has a delicate and complex chemical structure. At room temperature, borax appears as a colorless translucent crystal, or a white crystalline powder, which is slightly brittle and delicate to the touch.
Among the chemical properties of borax, its solubility in water is quite significant. Borax is soluble in water, and when dissolved, a hydrolysis reaction occurs, making the solution alkaline. This is because the borate ions in borax can be combined with hydrogen ions ionized by water, resulting in a relative increase in the concentration of hydroxide ions, so the solution is alkaline.
Borax also has a certain thermal stability. When heated, borax will gradually lose its crystalline water, and with the increase of temperature, it will further decompose. Under certain high temperature conditions, borax will decompose into boron anhydride and other substances.
Borax can often participate in many reactions as a source of boron in chemical reactions. Because of the boron element in its structure, it can react with other elements or compounds to form new compounds. For example, borax can react with acids to form products such as boric acid.
Furthermore, borax also has a special reaction with metal ions. Borax can form complexes with some metal ions, which makes it useful in metallurgy, electroplating and other fields. The chemical properties of borax are rich and diverse, and its solubility, thermal stability, and reaction characteristics with acid and alkali, metal ions make it widely used in many fields such as chemical industry, medicine, and food. It is actually an important substance in the chemical field.

Mercury is a highly toxic substance. According to the relevant records of mercury and cinnabar refining in "Tiangong Kaiwu", cinnabar (HgS) can be produced by calcination and sublimation. The method is as follows:
Place cinnabar in a special airtight container, which needs to be resistant to hot topic. One end of the container is provided with a thin tube to conduct gas. Then it is calcined in a furnace, and the cinnabar is thermally decomposed, and the reaction is HgS + O < $\ stackrel {high temperature }{=\!=\!=}$ Hg + SO
. Mercury is heated into mercury vapor, which escapes along the air duct, and condenses into liquid mercury droplets when cold.
However, the process of mercury smelting cinnabar overflows with toxic gas, which is extremely harmful. " "Tiangong Kaiwu" also mentioned that those who engage in this industry are often affected by mercury poisoning and their bodies gradually decline. In order to prevent mercury poisoning, the ancients also had protective methods, such as introducing mercury gas into long bamboo tubes, so that mercury can be dripped into the water, and the evaporation of mercury gas can be reduced by water sealing; or covering the mouth and nose with a damp cloth during work to slightly reduce the inhalation of poisonous gas.
As for the synthesis of dimercaptopropanol, this is a modern chemical achievement. At the time of "Tiangong Kaiwu", this technique was not heard of. Modern synthesis of dimercaptopropanol, mostly with propenol as the starting material, is obtained by adding 3-chloro-1-propanol with hydrogen chloride, and then reacting with sodium hydrosulfide to introduce mercapto groups, which can be prepared by multi- This process requires precise control of the reaction conditions and steps, which is very different from the ancient method of mercury refining.

Good, I want to understand the need for storage and transportation, this is a sincere and important thing. In the way of hiding, the first place for storage, choose a high and dry place to prevent the ground from being wet and rotten. If it is in a humid place, although there are treasures, it is also easy to be damaged. And the installation of the warehouse must be strict, so that it can withstand the wind and rain and prevent thieves. If there is a gap in the wall of the warehouse, and the wind and rain can enter, all things will be harmed; if the protection is not strict, thieves will spy on it, and the hidden things will not be protected.
Furthermore, there is also attention to the method of hiding things. All things should be classified and hidden, and they should not be mixed. Such as wheat, it is appropriate to store dry; cloth silk and linen, it is necessary to avoid moisture and insects. If it is not classified, the physical properties are mutually exclusive, and it is easy to cause damage. And when hiding objects, it is advisable to check them regularly. If there is any mildew or insect-eaten appearance, it should be disposed of quickly and cannot be delayed.
As for the transportation business, the first thing is the choice of transportation capacity. When looking at the number and weight of objects, choose the car and boat that suits it. If there are few and light objects, you can carry them in a small cart; if there are many and heavy objects, you need a cart or a boat. And the car and boat used must be sturdy and intact. If there is any damage, it is easy to change on the way.
When transporting, you should also pay attention to the time and place. There are wind, rain, frost and snow in the sky, and mountains and rivers are dangerous. In case of wind and rain, you need to avoid a safe place, and wait for the weather to clear before proceeding, and do not venture forward rashly, so as not to damage or hurt people. Crossing mountains and rivers and dangerous places, you should be especially cautious, examine the path, and pass slowly to prevent tipping over.
Furthermore, the escort is elected as a loyal and reliable person. He should do his duty and not slack off. Guard the goods all the way to prevent theft and robbery. If there is negligence, causing the loss of the goods, the responsibility is not light. Therefore, careful attention should be paid to the matter of storage and transportation, and caution should be taken to ensure the safety of the goods and achieve the purpose of transportation.