5-bromo-2-chloropyridine-3-carboxylic acid

The physical properties of 5% to 2% of boric acid are similar to those of -3% boric acid. Boric acid is often white crystalline powder or yellow-colored flake crystals, and its external surface is low and low.
and melting, the melting of boric acid is characteristic, and it is around 169 ° C. At this degree, boric acid is solidified and reformed from a solid solution, which shows the physical properties of boric acid. And its boiling time cannot be ignored. The degree of resistance rises to > 300 ° C, and boric acid is the boiling time. This substance is transformed from a liquid to a liquid.
Furthermore, the solubility of boric acid is also one of its important physical properties. In water, boric acid has a certain solubility, and the solubility of boric acid varies with the increase and decrease of the degree of solubility. In general, the solubility of boric acid in water also increases when the degree of resistance increases. In the room environment, boric acid can be slowly dissolved in water to form a boric acid solution, which is weakly acidic.
Its density is also fixed, usually around 1.435g/cm ³. This density characteristic makes boric acid a specific sink or float in the polycomplex, depending on the density of the medium.
In addition, the crystal of boric acid gives its specific optics. The refractive and reflective properties of its crystals make boric acid also have its own characteristics in the optical field, and may be useful in some optical materials.
Therefore, the physical properties of 5% -2% boric acid, such as melting boiling, solubility, density to light, etc., together contribute to its specificity in the physical world, which lays the foundation for its use in multiple fields.

Mercury is a highly toxic substance and is also a metal element. It is liquid at room temperature. It is active and has many unique characteristics.
Mercury is highly volatile and can slowly turn into mercury vapor and disperse in the air at room temperature. This mercury vapor is invisible and colorless, but it is extremely toxic. Once inhaled into the human body, it is extremely difficult to metabolize and excrete, causing serious damage to the nervous system, kidneys and many other organs.
Mercury has unique chemical properties. It can form alloys with many metals, and these alloys are called amalgams. For example, mercury can form amalgams with metals such as silver and gold. In the past, this property was often used when refining gold and silver. Mercury can react with oxygen. When heated, mercury will combine with oxygen to form mercury oxide. This reaction is quite typical and is often used as an example in chemical experiments.
The reaction of mercury with acids also has special features. Mercury is usually difficult to react with dilute hydrochloric acid and dilute sulfuric acid because its metal activity is after hydrogen. However, mercury can react violently with nitric acid to form products such as mercury nitrate.
In nature, mercury mostly exists in the form of mercury sulfide, which is cinnabar, with a bright color of vermilion. Mercury sulfide is relatively stable chemically, but under certain conditions, such as high temperature calcination, mercury sulfide will decompose and release mercury.
In addition, mercury is very harmful to the environment. If mercury is released into the environment without proper treatment in industrial production, it will accumulate in water and soil. Through the enrichment of the food chain, it will eventually endanger human health. Therefore, the use and treatment of mercury must be extremely cautious and follow strict norms and standards to prevent it from causing irreversible disaster to humans and the environment.

For those with 5% -2% water to -3% boric acid, the main use is good.
Boric acid is used in the way of cleaning and detoxification. It has the effect of clearing and detoxifying, and is often used on the surface. If the skin is slightly broken or lost, wash it with an appropriate degree of boric acid solution, which can prevent infection and promote the surface. And in ophthalmology, boric acid is also commonly used. For eye pain, eye inflammation, etc., washing the eyes with boric acid solution can solve the problem and reduce the appearance of the eyes.
In the chemical industry, boric acid is also indispensable. In glass making, adding boric acid can improve the properties of glass. It increases the quality of the glass and is not easy to break due to the quality of the glass. It can also improve the transparency of the glass, making it more transparent. In the production of ceramics, boric acid can be used as a melting aid, reducing the melting degree of the ceramic billet, saving fuel, and making the ceramic surface smoother and more colorful.
In the process of production, boric acid also has its uses. Boron is an essential trace element for plant growth. Boric acid can be used as boron fertilizer. Applied to soil, it can help plant root cultivation and increase plant resistance to diseases. For rape, cotton and other crops, the application of boric acid can promote its flower and fruit, improve the fruit setting rate, and increase the amount of fruit.
In addition, in the production of fireproof materials, boric acid is also effective. Boric acid is added to wood, wood and other materials, which can improve its fire resistance. In case of fire, boric acid decomposes to form glass, which covers the surface of the material, isolates oxygen, inhibits combustion, and has the effect of fire retardancy.

5-Hydroxy- 2-furanal, also known as furfural, is synthesized by a method that is not directly described in Tiangong Kaiwu, but according to ancient chemical processes and later generations' ideas for the preparation of related substances, there are the following common methods.
First, it is obtained by hydrolysis and dehydration of agricultural and sideline products. Many raw materials rich in polypentosaccharides, such as corn cobs, bagasse, cottonseed hulls, etc., are first treated with acid. The acid solution can promote the hydrolysis of polypentosaccharides and convert them into pentosaccharides. This process is similar to the process of doping cattle, accurately dismantling complex polysaccharide structures. Subsequently, the pentosaccharides are further dehydrated and cyclized under suitable conditions to generate furfural. This transformation is like a phoenix nirvana, and after changes, furfural is finally For example, furfural can be obtained from corn cobs catalyzed by dilute sulfuric acid and reacted at a specific temperature and time. This raw material is widely sourced and low-cost, which is in line with the ancient concept of using natural products.
Second, the direct dehydration method of pentose. When pentose is directly available, select the appropriate catalyst, such as some metal salts or solid acids, under the action of pentose, the pentose can be efficiently dehydrated to generate furfural. This process is like turning a stone into gold. With the help of catalysts, pentose quickly converts to furfural. This method is relatively direct and can avoid the complicated steps of raw material pretreatment. However, the requirements for the source of pentose are relatively high, and it may not be easy to obtain pure pentose in ancient times, or additional refining processes are required.
Third, the pyrolysis route of biomass. Biomass is pyrolyzed in an isolated air or low-oxygen environment. During this process, the chemical bonds inside the biomass are broken and recombined, resulting in a variety of products including furfural. Pyrolysis conditions such as temperature and heating rate have a great impact on the yield of furfural. This method is similar to chestnut extraction in fire. Furfural is obtained in complex pyrolysis reactions. Although biomass can be comprehensively utilized, the products are complex, and the separation and purification of furfural requires fine processes. In terms of ancient technology, it may be quite challenging, but it is also the direction of exploration.

Mercury, a highly toxic substance, should be stored and transported with caution.
First word storage. Mercury must be stored in a dense container. Because it is highly volatile, if it is not sealed, the mercury gas will escape in the air, and it will be harmful to human health if it is inhaled. And the mercury container should be placed in a cool, dry place to avoid heat and humidity. Heat will evaporate mercury more quickly, and it will be wet or cause the device to rot and release mercury. And it should be kept away from fire sources and strong oxidants, mercury and strong oxidizing substances, or violent changes will occur, leading to disaster.
Times and transportation. Mercury transportation, the choice of good equipment is crucial. The equipment used must be sturdy, capable of withstanding vibration and collision, and preventing its damage and mercury flow. During transportation, keep the speed of the vehicle constant to avoid sudden brakes and crashes, and ensure the safety of the mercury equipment. The escort must be clear about the nature of mercury and know the emergency measures. If there is mercury leakage, it will be covered with sulfur quickly. Mercury and sulfur combine to form mercury sulfide, and the toxicity will be greatly reduced. And the place where mercury is discharged should be quickly surrounded, and people should not be allowed to enter, so that mercury gas will not hurt people.
Furthermore, in the place of storage and transportation, a warning sign should be prepared, indicating the presence of mercury, so that others will know the risk and avoid it. Ventilation equipment is also provided. If the mercury gas is slightly released, it can be quickly discharged outside, reducing the concentration of mercury gas in the room. Those who handle mercury must wear protective equipment, such as gloves, masks, goggles, etc., to prevent mercury from touching and entering the body.
The storage and transportation of mercury is related to the well-being of everyone and the safety of the environment. All things need to be cautious and must not be slack at all to ensure that nothing goes wrong.