4-Hydrazinopyridinehydrochloride

The main use of 4-alkylpyridine and its carboxylic acid pyridine is due to its extraordinary effect in multiple domains.
In the way of, 4-alkylpyridine and its carboxylic acid pyridine are important raw materials for the synthesis of polymers. For example, some antibacterial compounds, with their groups, can refine the specific properties of molecules, and give antibacterial activity, so that can target specific parts of bacteria, dry its normal physiological generation, and bacteriostatic, bacteria purpose, to human health.
In addition, in the field of, these two are also important functions. It can be synthesized with high efficiency, low toxicity and environmental friendliness. It can accurately act on the disease and damage of crops, inhibit the growth and breeding of harmful bacteria, and control the propagation and control of pathogens, protect crops from disease invasion, increase productivity and harvest, and have little environmental harm. It meets the needs of color development.
In addition, in the field of materials, 4-alkylpyridine and its carboxylic acid pyridine also show their unique charm. It can be used in the synthesis of polymer materials with special properties, such as some polymers, optical materials, etc. Due to the particularity of molecules, it can introduce special functionalities into materials, and control the properties and optical properties of materials, etc., so that materials have a promising future in sub-devices, optical devices, etc., and promote the next step in phase technology.
In the field of chemical analysis, it can be used for specific analysis. By means of its specific analysis of certain materials, it can be used to identify sensitive, local and specific ingredients in certain products, to assist scientific research and the precise analysis of the components of products in the industry, so as to ensure the quality of products and the benefit of production.

4-butyric acid and its esters are all compounds. Among them, 4-butyric acid, often in the form of black-colored, white-flavored liquid or white crystalline solid, is deliquescent and easily soluble in water, ethanol and ethyl ether. And 4-butyric acid esters, also in liquid or solid, have poor solubility due to different ester groups.
4-butyric acid has a certain acidity and can partially produce molecules in water. Its molecule contains a carboxyl group, which makes it capable of esterification and inversion, such as the formation of enoic acids from water. However, under the catalysis of acid or alcohol, the hydrolysis reaction can be generated, and 4-butyric acid and alcohol phase can be regenerated.
For physical properties, 4-butyric acid is melted at 50 ° C and boiled at 204-205 ° C. The viscosity of the liquid and the surface force also have specific values. The melting boiling of 4-butyric acid esters depends on the shortness and stability of the ester-based carbon. Generally speaking, the carbon is increased, and the boiling phase is increased.
4-butyric acid and its esters have certain uses in the fields of chemistry, chemical industry, etc. However, it should be noted that 4-butyric acid is used in controlled substances illegally, causing serious harm to human health, such as depression, coma and even life-threatening. Therefore, when it comes to this substance, it must be used in accordance with relevant laws and laws, reasonably and safely.

The chemical properties of 4-hydroxypyridine and its carboxylic acid anhydride are quite stable. 4-hydroxypyridine, with the characteristics of phenolic hydroxyl groups, is acidic and can react with bases to form salts. After it is converted into carboxylic acid anhydride, the structure changes and the chemical properties also change accordingly.
This carboxylic acid anhydride, due to the existence of an intramolecular conjugate system, has a more uniform electron cloud distribution, making the overall structure stable. From the perspective of reactivity, compared with general acid anhydride, its reaction with nucleophiles requires more severe conditions.
Taking the hydrolysis reaction as an example, common acid anhydride is easily hydrolyzed into the corresponding carboxylic acid under the catalysis of mild water and acid base. However, the 4-hydroxypyridine carboxylic acid anhydride, due to the conjugation of the pyridine ring and the acid anhydride group, weakens the positive electricity of the carbonyl carbon, and increases the difficulty of attacking the nucleophilic reagent. Therefore, during hydrolysis, higher temperatures and stronger acid-base conditions may be required.
According to the theory of alcoholysis, normal acid anhydrides and alcohols are prone to alcoholysis to form esters and carboxylic acids. However, the reaction rate of 4-hydroxypyridine carboxylic acid anhydride and alcohol is slow, and a specific catalyst and suitable reaction environment are required to proceed smoothly.
This stability is due to the electronic effect and space effect of the pyridine ring. The nitrogen atom of the pyridine ring has electron-absorbing properties, which disperse the positive charge of At the same time, the steric barrier of the pyridine ring also prevents the nucleophile from approaching the carbonyl carbon, further enhancing the stability of the carboxylic acid anhydride.
Overall, the chemical properties of 4-hydroxypyridine carboxylic acid anhydride are stable, and they show lower activity than general acid anhydrides in many chemical reactions. Specific conditions are required to achieve the corresponding conversion.

To make 4-pyridylbutyric anhydride, you can follow the following ancient method.
First take an appropriate amount of 4-pyridylbutyric acid and place it in a clean kettle. The kettle should be made of clay or copper or iron, and it should be temperature-resistant and not phase with the material. Add an appropriate amount of dehydrating agent, such as acetic anhydride or phosphorus pentoxide. The amount of this dehydrating agent, when weighed accurately, must be in a suitable ratio to 4-pyridylbutyric acid. Generally speaking, if acetic anhydride is used as the dehydrating agent, the molar ratio to 4-pyridylbutyric acid is about 2:1.
Then, slowly heat the kettle with a gentle fire. The size of the fire must be adjusted carefully, so as not to cause the material to carbonize due to excessive fire. When heating, the material in the kettle gradually changes, bubbles escape, and smoke rises. This is the appearance of the reaction going on. Maintain heating, so that the temperature in the kettle gradually rises to between 120-150 degrees Celsius, and continue this temperature to make the reaction sufficient. In the meantime, a pestle with a long handle needs to be used to stir the material in the kettle in a timely manner, so that the heating is uniform and the reaction is more smooth.
Wait until the reaction in the kettle is smooth, no more bubbles escape, and the smoke gradually dissipates, which can be regarded as the reaction is almost complete. At this time, remove the kettle from the fire and wait for it to cool slightly. The product in the kettle is then poured into a vessel containing an appropriate amount of ice water. The use of this ice water is to make the product suddenly cool and separate, and to wash away unreacted dehydrating agents and other impurities. When poured in, the product can be seen gradually coagulating in ice water, like a paste.
Filtered with filter paper to obtain a filter cake. The filter cake is crude 4-pyridyl butyric anhydride. Then an appropriate amount of organic solvent, such as ether or petroleum ether, is used to recrystallize the filter cake. The method of recrystallization is to place the filter cake in a solvent, dissolve it with slight heat, and then let it stand and cool to allow it to slowly crystallize. Repeat this several times to obtain pure 4-pyridyl butyric anhydride. It is white in shape and delicate in texture, like frost and snow.
To make this thing, you need to be careful. Every step is related to success or failure. From the weighing of the material, the grasp of the heat, to the fine operation of recrystallization, all cannot be ignored. In this way, satisfactory results can be obtained.

4-Carboxylpyridine and its hydrochloride have many precautions in storage and transportation. This substance has certain chemical activity, and should be stored in a cool, dry and well-ventilated place. Because it is quite sensitive to humidity, moisture can easily cause changes in nature, so the ambient humidity should be strictly controlled, and the humidity should be maintained at a relatively low level, about 40% - 50% is appropriate. At the same time, the temperature should not be too high, generally should be controlled at 20 ° C - 25 ° C to prevent thermal decomposition or other chemical reactions.
Furthermore, the storage place must be kept away from fire, heat sources, and avoid direct sunlight. Because it may be flammable or heat can easily cause dangerous reactions, open flames and high temperatures may have serious consequences. Moreover, it should be stored separately from oxidants, alkalis, etc., and must not be mixed, because it is in contact with these substances or reacts violently, which endangers storage safety.
The transportation process should also not be ignored. It is necessary to ensure that the packaging is complete and well sealed to prevent leakage. The transportation vehicle should be selected with the corresponding qualifications and can meet the safe transportation conditions. During transportation, it is necessary to prevent exposure to the sun, rain, and avoid high temperature and humid environment. Drivers and escorts also need to be familiar with the characteristics of the substance and emergency treatment methods. In the event of an accident, they can respond quickly and correctly. When loading and unloading, they should be handled lightly. It is strictly forbidden to drop, touch, and collide to prevent the leakage of substances caused by damaged packaging, which will cause safety and environmental problems.