"Tiangong Kaiwu" says: Mercury, also known as mercury. Its most important use is as a medium for silver plating, so that the silver can be firmly attached to other things. It can also be used in alchemy techniques, but this technique is not available today.
Mercury is very important in silver plating. The craftsman fused mercury and silver to make an amalgam, applied it to the utensils, and then heated to evaporate the mercury, leaving the silver on the surface of the utensils to form a uniform and firm coating. This technique has many applications in the production of ancient gold and silver utensils, mirror manufacturing, etc., making the utensils beautiful and durable.
In ancient alchemy, mercury was also often one of the raw materials. The alchemists believed that mercury had magical properties and could refine the elixir of immortality. However, after years of verification, this statement is absurd, and mercury is toxic and harmful to the body.
Water, the source of life, is essential to all things in the world. For people's livelihood, it is the foundation of drinking and irrigation. If people do not have clean water, it is difficult to survive; if the fields are not irrigated with water, the crops will not be harvested, and people's livelihood will be difficult.
In industry, water is an indispensable medium and power. In metallurgy, water can cool metals; in the textile industry, it can help dye fabrics evenly. Hydraulic power can also drive machinery, such as ancient water wheels, which provide power for mills and workshops and help production.
Bamboo Ruo has a wide range of uses. For food, it can wrap food. For example, during the Dragon Boat Festival, bamboo ruo is used to wrap dumplings, so that the glutinous rice has a unique fragrance. It is also used in tea making, and bamboo ruo is used to wrap tea cakes, which can prevent moisture, keep fresh, and help preserve the aroma of tea. In addition, bamboo ruo can be woven into a hat to protect farmers and pedestrians from the wind and rain on rainy days.

Mercury, bromine, and gallium are three special substances, each with unique physical properties, and have been involved in ancient records.
Mercury, liquid at room temperature, is a silver-white shiny heavy liquid, with stable chemical properties and insoluble in acids and alkalis. "Historical Records · Qin Shi Huang's Benji" states: "Mercury is a hundred rivers and seas, and it is instilled organically." It can be seen that the ancients knew long ago that mercury has liquid characteristics and metallic luster characteristics. Its density is high, its fluidity is good, it is volatile, and mercury vapor is highly toxic.
Bromine, a dark reddish-brown smoky volatile liquid at room temperature, has a pungent smell, is highly corrosive, and can be dissolved in water and organic solvents. Although the ancients did not record as much as mercury, they knew that it was irritating, bromine was volatile, and its liquid and vapor were strongly irritating and corrosive to the skin, eyes, and respiratory tract.
Gallium, with a low melting point, melts into a liquid state at 29.78 ° C. When solid, it is a blue-white metal, which is soft. When liquid, it has good fluidity, greater density than aluminum, and has supercooling phenomenon, that is, it can still not solidify temporarily when cooled below the melting point. Gallium was not clearly recognized in ancient times, but recent studies have found its unique physical properties.
These three have special physical properties and are widely used in chemistry, materials science, and other fields, which are of great significance to promoting the development of science and technology.

Mercury is cold and heavy in nature. At room temperature, it is liquid and has a metallic luster, and its shape is like mercury flowing. Mercury is volatile, and its vapor is toxic. It can enter the body through the respiratory tract and accumulate in the viscera, which is harmful to people's health.
River people are mostly the aggregation of water. Its nature is soft and smooth, and it is divided into objects. It flows in ravines and nourishes all things. However, river water is also easily contaminated. If debris enters it, it will become clear and turbid, and aquatic things will also be harmed.
Boron is brittle and hard, and its chemical properties are relatively stable. Boron is often in a normal valence state in compounds, and can combine with a variety of elements to form substances with different properties. Under high temperatures, boron can react with oxygen, nitrogen, etc., showing lively chemical properties.
Alum, mostly water-containing double salts of sulfate, with different colors, such as white, blue, green, etc. Alum has the properties of convergence and dryness, and is widely used in industry and life. Such as alum, it can purify water and make sundries in the water condense and settle.
These numbers have different properties, and they are used differently. They have their own positions in heaven and earth. People should recognize their properties and make good use of them, so as not to cause harm, but to benefit people.

To prepare 1-bromo-4-butene-2-iodobenzene, there are many ways to synthesize it.
First, benzene can be used as a starting material and bromine atoms can be introduced into a specific position of the benzene ring through halogenation reaction to obtain bromobenzene. Then, bromobenzene and a suitable halogenated hydrocarbon containing butene structure are used under the action of a metal catalyst to couple the butene structure to the benzene ring. Then, the obtained product is iodinated to introduce iodine atoms at a specific position, so that the target product 1-bromo-4-butene-2-iodobenzene may be obtained.
Second, the aromatic hydrocarbon containing butene structure can also be used as the starting material. First, bromine atoms are introduced into the benzene ring through halogenation reaction, and then, under suitable conditions, the specific position of the benzene ring is iodized to obtain the target compound. This process requires precise control of the reaction conditions to ensure that the position where the halogen atoms are introduced is accurate.
Furthermore, it can also be considered to construct an intermediate of the benzene ring and butene structure, and then bromine atoms and iodine atoms are introduced respectively. For example, a benzene ring derivative containing butenyl groups is prepared first, and then bromine and iodine are introduced at the desired positions according to the selectivity of the halogenation reaction. The key to this process is to control the reaction activity and selectivity, and to promote the reaction to the target product with the help of suitable catalysts and reaction conditions. It should be noted that different synthesis methods have their own advantages and disadvantages. In actual operation, it is necessary to comprehensively consider the availability of raw materials, the difficulty of reaction conditions, the high and low yield and many other factors to select the most suitable synthesis path.

Mercury, rivers, and lead ingots must be stored and transported with caution. Mercury is a highly toxic substance that is easily volatilized at room temperature and forms mercury vapor. If people absorb it, it will damage the brain and viscera. For storage, it is necessary to choose a closed and corrosion-resistant device, and place it in a cool and well-ventilated place to prevent it from leaking. Because once leaked, mercury beads will be scattered in the ground, difficult to collect, and its vapor will diffuse and endanger the surrounding area. During transportation, the packaging must be solid to prevent vibration and collision from causing damage to the container.
The storage and transportation of rivers is related to water conservancy and water transportation. When storing water, the stability of dams and reservoirs is essential. If the dams are not strong, they will collapse in case of floods, which will affect the people downstream. Water pipelines and canals need to be prevented from leakage and blockage, and regular maintenance. In water transportation, pay attention to the depth, width and water flow rate of the river to ensure the safety of navigation of ships, and avoid sewage entering the river, so as to avoid bad water ecology.
Store lead ingots in a dry and ventilated place, because they are easy to oxidize in case of moisture, which will damage the quality. Stacking should be stable to prevent dumping and hurting people. During transportation, it should be firmly fixed and avoid displacement and collision, and protection and warning signs should be equipped according to regulations. Because lead is toxic, accidental contact and inhalation of lead dust will harm human health.
All three are important in storage and transportation, safety and quality. They all need to be operated in accordance with regulations to protect the safety of people, materials and the environment.