5-Chlorothiophene-2-carboxilic acid

Borax, cold and salty in nature. Its quality is colorless and translucent crystals, or white crystalline powder, which can be slowly weathered in air. Its crystals are often columnar, granular, and polymerized into clusters, kidneys, etc., with a characteristic appearance.
The density of borax is moderate, about 1.73g/cm ³, which is similar to common salts. Its hardness is not high, Mohs hardness is about 2-2.5, slightly softer than gypsum, so it can be delicate and easy to be scratched when touched.
Borax is soluble in water, which is one of its important physical properties. In hot water, its dissolution rate is especially fast, and the solution is alkaline. This alkalinity is not as strong as caustic alkali, but it also has certain chemical activity. The melting point of borax is about 741 ° C. When heated to this point, borax gradually melts from solid to liquid, just like ice and snow melt when heated. When the temperature further increases, borax will undergo a series of complex chemical changes, which involve its chemical properties.
Borax is relatively stable at room temperature and can be stored for a long time without obvious qualitative changes. However, if the environmental temperature and humidity change drastically, or encounter special chemical substances, its properties will also change. Although the ancients did not know the physical properties of borax as accurately as people do today, in long-term practice, they were also well aware of its characteristics of coolness, softness, and solubility, and applied it to many fields, such as medicine, alchemy, metallurgy, etc. Borax can be seen, making a unique contribution to the development of ancient science and technology.

Borax has unique chemical properties. Borax is sodium tetraborate containing crystalline water.
First, it is alkaline. The aqueous solution of borax is alkaline, and it is hydrolyzed in water to produce hydroxide ions. In water, borax dissociates, and some borate ions will combine with hydrogen ions ionized by water, causing the ionization balance of water to shift to the right, so that the concentration of hydroxide ions in the solution increases, showing an alkaline state. This alkaline property makes it useful in many fields. For example, in traditional washing processes, it can be used as an auxiliary to enhance the decontamination power, because alkalinity helps to hydrolyze and remove grease and other dirt.
Second, it has buffering properties. The solution of borax can maintain a certain pH value. When a small amount of acid or alkali is added to the outside world, it can move through its own hydrolytic equilibrium, so that the pH value of the solution changes very little. This buffering performance is crucial in many chemical experiments and industrial production. For example, in some chemical reaction systems, it is necessary to maintain a specific pH environment. Borax solution can play the role of stabilizing pH value and ensure the smooth progress of the reaction.
Third, it can react with acids. Borax can react with strong acids to form boric acid and corresponding salts. This reaction reflects the generality of its salts. Take hydrochloric acid as an example. Borax reacts with hydrochloric acid to obtain boric acid and sodium chloride. Boric acid is also widely used in many fields, such as medicine, glass manufacturing and other industries. < Br >
Fourth, it is easy to decompose when heated. When borax is heated, it will gradually lose its crystal water, and then decompose. This characteristic is used in metallurgy and other fields. For example, in the process of metal welding, the borax is thermally decomposed to produce the effect of melting, helping to remove oxides on the metal surface and making the welding more firm.

Borax is a common mineral medicine. Its main application is to clear away heat and detoxify, reduce swelling and antiseptic, and is mostly used for swelling and pain in the throat, sores in the mouth and tongue, and obstruction of the eyes.
In the treatment of swelling and poison in sores, borax can be applied externally. In case of swelling and pain in the throat, borax can be combined with borneol, Xuanming powder, etc. to blow on the affected area, which can clear away heat and reduce swelling, and relieve pain in the throat. In the case of sores in the mouth and tongue, use borax to grind the end and apply it externally, which can help the sores heal and relieve pain. If the eyes are swollen and painful, and the eyes are obscured, borax can also exert its effect of clearing away heat and improving the eyes. It is often used in combination with other medicines that clear the
And because of its antiseptic properties, in ancient times, it was also occasionally used for food preservation, but the dosage needs to be precisely controlled to prevent excessive ingestion and harm to the body. At present, due to health and safety considerations, it has been used less in the food field.
Borax taken internally still has the effect of promoting phlegm, which can help the discharge of sputum and relieve the symptoms of cough and phlegm. However, it is cold in nature and has certain toxicity. When taken internally, it should be taken with caution and strictly follow the instructions of doctors. Do not take it at will, so as to avoid poison and evil invading the body, causing damage to the viscera, and causing many adverse diseases. If used properly, it can be a good medicine for treating diseases and saving people. If it is missed, it may become a poison that hurts people. Doctors and patients should be careful.

To prepare 5-bromouracil-2-carboxylic acid, there are various methods. Common ones include bromination of uracil-2-carboxylic acid with suitable halogenating agents. Among the halogenating agents, bromine, N-bromosuccinimide (NBS), etc. can be used.
If bromine is used, first dissolve uracil-2-carboxylic acid into an appropriate solvent, such as glacial acetic acid, dichloromethane, etc., cool it, slowly drop bromine, and react at low temperature. When reacting, pay close attention to the reaction process and monitor it with suitable detection methods, such as thin layer chromatography (TLC). When the raw material is completely converted, stop the reaction. After separation and purification, such as extraction, column chromatography, etc., the target product can be obtained.
If N-bromosuccinimide is used, the substrate is also dissolved in a suitable solvent, and an initiator, such as benzoyl peroxide, is often added to initiate the reaction. N-bromosuccinimide is used as the bromine source, and the reaction conditions are relatively mild and there are few side reactions. After the reaction is completed, the same separation and purification steps are taken to obtain 5-bromouracil-2-carboxylic acid.
In addition, other bromine-containing reagents are also used as raw materials and prepared by multi-step reaction. First protect the specific position of uracil-2-carboxylic acid, then introduce bromine atoms, and then deprotect the group. Although this approach is complicated, it can precisely control the reaction check point and improve the purity of the product.
There are various methods for preparing 5-bromouracil-2-carboxylic acid, each with advantages and disadvantages. Experimenters should choose the appropriate method according to their own conditions, raw material availability and product requirements.

5-% carboxylic acid in juice and storage, pay attention to the general situation.
The carboxylic acid of juice has certain characteristics, and it should be stored in the first heavy container. Materials that can withstand the corrosion of these two, such as specific plastic materials or glass containers, are required. If gold containers are used, they may be damaged and biochemical reactions and chemical reactions.
The storage environment is also good. It should be placed in a dry, dry and good environment, protected from direct light and high temperature. Because of high temperature, it is easy to make juice, carboxylic acid or shadow, such as accelerated decomposition or polymerization. And it is necessary to prevent explosion or fire.
It is necessary to prevent explosion or fire. The container needs to be sealed and leaked, and additional anti-leakage is added to prevent collision and breakage. The container should be unloaded and placed without severe shock. The container should also comply with the requirements of the relevant hazardous chemicals and be equipped with necessary emergency equipment.
In addition, if there is no storage or storage, it is necessary to follow the appropriate operating procedures. People who work hard are familiar with the characteristics and emergency management methods of the two. If there is leakage and other problems, it can be quickly and properly placed to reduce harm. In addition, be careful to wait for the storage and loss of carboxylic acid in the juice to ensure safety.