Although 4-hydroxyquinoline was not as widely recognized in the era covered by "Tiangong Kaiwu" as in modern times, it is speculated from a modern perspective that its use may be related to some processes at that time.
In the field of traditional medicine, although the specific structure and efficacy of 4-hydroxyquinoline may not be clearly known at that time, some natural plants may contain similar structural components or be used for simple medicinal attempts. In ancient times, doctors often sought cures from natural plants and trees, and some plants containing similar structures of 4-hydroxyquinoline may have been used to treat some common diseases, such as clearing heat and detoxification.
In terms of dyes, 4-hydroxyquinoline or its related compounds may become potential components in the extraction process of ancient dyes. Ancient dyeing workshops mostly extracted dyes from natural plants and minerals. If the raw materials used contain 4-hydroxyquinoline structure, under specific extraction processes, they may be able to dye fabrics with unique colors. For example, some special plants contain similar ingredients that may have a dyeing effect on fabrics after soaking, boiling and other processes, and the dyed fabrics may have unique performance in terms of color durability.
In terms of metallurgical aids, in the development of ancient metallurgical technology, in order to make the metal smelting effect better, various additives were often used. Some chemical properties of 4-hydroxyquinoline may play a role in the metallurgical process, such as helping to separate impurities and improve metal properties. Although its chemical structure was not clear at that time, in long-term practice, or by chance, substances containing such components were found to be helpful to metallurgy and used.

4-Isoquinoline is a chemical compound with many physical properties. Its white to light crystalline powder is usually solid under normal conditions, and the melting time is between 70 and 73 ° C. This characteristic makes it suitable for solid solution under specific conditions. It is especially valuable in material synthesis and some chemical reaction process control.
4-Isoquinoline has a high boiling time of 267 ° C, indicating that its molecular force is low. The high boiling properties make it have good quality in normal conditions, and it is not easy to be damaged due to low temperature waves. It is important for phase products that need to be stored or used in normal conditions.
In terms of solubility, 4-Isoquinoline is slightly soluble in water, and is easily soluble in ethanol, ether, chloroform, etc. This difference in solubility is due to the fact that the molecule contains both a hydrophobic quinoline group and a hydrophobic quinoline group, which makes it different in different solubility. The first characteristic can be used as an important basis for the separation, extraction and preparation of solution products.
In addition, 4-quinoline has certain optical properties. Because of the existence of a co-system of molecules, it can absorb specific waves of ultraviolet light and produce light under specific conditions. This optical property makes it useful in the fields of optical materials, optical detection, etc., and researchers can use this property to generate energy for specific substances or environmental transformation.
Furthermore, 4-quinoline crystals are integrated, and the molecules are arranged in an orderly manner through interactions. Crystal properties such as hardness and density also have an impact on its physical properties. In terms of crystal engineering and solid materials, the crystalline properties of 4-quinoline can provide a foundation for the construction of new functional materials.

4-Hydroxyquinolinyl boron, this physical property is special. It is an organic boron compound with a unique structure. It is connected by a quinoline ring to a boron atom through a hydroxyl group, giving it specific chemical properties.
On its stability, due to the conjugate system of the quinoline ring, the structure is relatively stable. However, the activity of the hydroxyl group is high, which can increase the reactivity. In case of electrophilic reagents, the hydroxyl oxygen is easy to supply electricity, which increases the activity of the boron check point and induces an electrophilic substitution reaction.
In terms of solubility, because the molecule contains polar hydroxyl groups and non-polar quinoline rings, it has a certain solubility in polar organic solvents such as ethanol and acetone, but has a low solubility in non
Optically, the conjugated structure of the quinoline ring gives it fluorescence properties. Under the excitation of light at a specific wavelength, electrons transition to high energy levels and emit light when they return to the ground state, which can be used in the fields of fluorescent probes, luminescent materials, etc.
Reactive activity is quite high. Hydroxyl groups can participate in esterification and etherification reactions; boron atoms have empty orbitals and can be used as Lewis acids to form complexes with molecules containing lone pairs of electrons such as amines and phosphines. This property has potential applications in the field of catalysis and can catalyze organic reactions, such as Diels-Alder reactions, Friedel-Crafts reactions, etc.
4-hydroxyquinoline-based boron has unique chemical properties and has broad application prospects in materials science, medicinal chemistry, catalytic chemistry and other fields, which need to be further explored and explored.

4 - The method of cutting calamine is obtained by crushing calamine and calcining it.
The steps are as follows: First take the high-quality calamine, and wash it with clean water to remove the sediment. To be washed and dried, place it in a special crucible. This crucible needs to be carefully made of fire-resistant clay and other materials, which can withstand high temperatures without burning.
And then, under the crucible, a raging charcoal fire is ignited, and the fire is calcined. Calcined, you need to pay close attention to the size of the heat and the shortness of the heat. The fire is weak, and the calamine can be fully melted; the fire is fierce, and it is feared that it will be damaged. It usually takes a long time to calcine the calamine with a suitable fire, until the calamine is of the color of the calamine, and the calcined stone is in place.
After calcining, quickly remove the crucible and place it in a good natural cold. When it is cold to normal, the calamine has been raw. Take out the calamine from the cold, and crush it again with a pestle and mortar and other tools until it becomes a powder.
In this way, there are many steps such as washing, calcining, cooling, and grinding, so that the 4-calamine of the essence can be obtained for the use of calamine and other purposes. This method can only be perfected by generations without groping and changing it, and it can be improved day by day to achieve a good raw material.

4-Hydroxyquinoline has many points to pay attention to during use. First, it is related to its solubility. 4-Hydroxyquinoline has low solubility in water, but it is soluble in some organic solvents, such as ethanol and acetone. When taking it, it is necessary to carefully select a suitable solvent according to specific needs to promote its full dissolution in order to achieve the desired use effect. If the solvent is not selected properly, it is very likely that it will not be evenly dispersed, which will affect the subsequent reaction or application effect.
Second, the stability cannot be ignored. The stability of this substance may be affected under light, high temperature and humid environments. Long-term light may cause its structure to change, resulting in reduced performance; under high temperature conditions, it may accelerate its decomposition; and humid environment is easy to make it absorb moisture, causing adverse effects on purity. Therefore, when storing, it should be selected in a cool, dry and dark place, properly stored, and sealed to prevent excessive contact with air and moisture.
Third, 4-hydroxyquinoline has a certain biological activity and is widely used in medicine, pesticides and other fields. However, it is because of its biological activity that it is necessary to pay close attention to its potential impact on the human body and the environment during use. In medicine, when used in drug synthesis, it is necessary to strictly control the dose and method of use, and fully consider the possible side effects and pharmacological reactions to ensure the safety of medication. When used in the field of pesticides, it is necessary to pay attention to its impact on non-target organisms, avoid unnecessary damage to the ecological environment, such as harm to beneficial insects and aquatic organisms, and strive to minimize its negative effects.
Fourth, the chemical reaction characteristics are extremely critical. In the molecular structure of 4-hydroxyquinoline, both the hydroxyl group and the quinoline ring have specific reactivity and can participate in many chemical reactions, such as substitution reactions, oxidation reactions, etc. When performing related reactions, it is necessary to precisely control the reaction conditions, such as temperature, pH, reaction time, and the proportion of reactants. If the reaction conditions are slightly deviated, different products may be generated, or the reaction yield may be low. For example, excessive temperature may cause side reactions and generate impurities, which may interfere with the acquisition of the main product; improper pH control may also affect the reaction rate and product selectivity. Therefore, its chemical reaction characteristics must be deeply understood and carefully controlled during use.