1,2-Dichloro-4-ethylbenzene, which is difficult to describe accurately in the era covered by Tiangong Kaiwu, but its use is inferred based on today's understanding, or has the following.
In the industrial field, it can be used as a raw material for organic synthesis. In organic synthesis, complex molecular structures are often required. 1,2-dichloro-4-ethylbenzene can participate in many chemical reactions due to its unique chemical structure. After ingenious transformation, it lays the foundation for the synthesis of more complex organic compounds with specific functions. For example, in the synthesis of fine chemical products, or key intermediates, through a series of reactions, important products such as drugs, fragrances, and dyes can be generated.
In the field of materials, it may also have its place. With the development of materials science, the demand for materials with special properties is increasing. 1,2-dichloro-4-ethylbenzene can be introduced into some material systems as a modifier or additive. For example, in polymer materials, adding an appropriate amount of this substance may change the physical and chemical properties of the material, such as improving the heat resistance and chemical corrosion resistance of the material, thereby broadening the application range of the material.
Furthermore, in terms of scientific research and exploration, 1,2-dichloro-4-ethylbenzene can be used as an important reagent to study the mechanism of organic reactions. By studying the various reactions they participate in, observing the reaction conditions, product formation laws, etc., researchers can gain in-depth insight into the essence of organic chemical reactions and provide a key basis for the improvement and development of organic chemistry theory.
Although this object is not included in "Tiangong Kaiwu", today, it has potential value in many fields such as industry, materials and scientific research, and promotes technological innovation and progress in various fields.

1% 2C2-dideuterium-4-pentenonitrile is an organic compound with specific physical properties and is widely used in the chemical industry. The following is described in the classical format of "Tiangong Kaiwu":
This 1% 2C2-dideuterium-4-pentenonitrile is colorless and transparent at room temperature, like the clarity of a clear spring. Its state is a flowing liquid with a uniform texture and no impurities. Looking at its color, it is like clear water, without colorful color, but reveals pure quality.
Smell it, there is a slight and specific smell, which is not pungent and intolerable, but it can also distinguish its unique smell. Although this smell is not strong, it is recognizable, such as the unique fragrance hidden in the mountains and forests, although light and palpable.
When it comes to volatility, it has a certain volatilization in room temperature environment, just like water vapor in spring, quietly escapes in the air, but the volatilization rate is not rapid, but slowly dissipates.
In addition to its solubility, it can be dissolved in many organic solvents, such as ethanol, ether, etc., just like salt melts in water, fusing seamlessly. This property makes it easy to mix with other substances in the field of chemical preparation and organic synthesis to form the needs of the reaction.
When it comes to density, it is slightly lighter than water. When placed in water, it is like a wood leaf floating on the surface of a lake, naturally floating up, showing a clear stratification. This sign of density can be used as a guide in the operation of separation and extraction.
Its boiling point and melting point are also key physical properties. When the boiling point reaches a certain temperature, the substance suddenly changes from liquid to gaseous state, such as ice disappearing under the warm sun and turning into water vapor. The melting point determines the conversion limit between its solid state and liquid state. When the temperature drops to the melting point, it solidifies from a flowing liquid to a solid solid. For example, when water turns into ice in a cold winter, the physical properties also vary between morphological changes.
The physical properties of this 1% 2C2-dideuterium-4-pentenonitrile are the cornerstone of its various uses in chemical industry and scientific research. Good use of it can add luster to various processes and create a new environment.

1% 2C2-dibromo-4-vinylbenzene is an organic compound with unique chemical properties. This substance is either liquid or solid at room temperature, and its color state is affected by purity and external conditions.
It contains bromine atoms and vinyl groups. Bromine atoms cause molecular polarity to increase. Due to the high electronegativity of bromine, the electron cloud is biased towards bromine, which increases the intermolecular force and has a relatively high melting point. At the same time, bromine atoms are highly active and can participate in many chemical reactions, such as nucleophilic substitution reactions. When attacked by nucleophilic reagents, bromine atoms can be replaced to form new organic compounds. They are often used as intermediates in organic synthesis. By substitution reactions, other functional groups are introduced to build complex organic molecular structures.
Vinyl imparts unsaturation to 1% 2C2-dibromo-4-vinylbenzene, which can undergo an addition reaction. Under suitable catalysts and conditions, the vinyl double bond opens and is added with hydrogen, halogens, hydrogen halides, etc. This property is of great significance in the preparation of specific structural organic compounds. Different addition reagents can be selected according to needs to synthesize the target product. Moreover, due to the presence of vinyl, the compound can also be polymerized to form a polymer, which is widely used in the field of materials science. The polymer made by polymerization reaction may have special properties, such as good mechanical properties, thermal stability, etc., and can be used to make plastics, fibers and other materials.
In addition, the chemical properties of 1% 2C2-dibromo-4-vinylbenzene are also affected by the benzene ring. The conjugated system of the benzene ring enhances the molecular stability and reduces some reactivity. However, the hydrogen atoms on the benzene ring can still undergo substitution reactions under appropriate conditions, such as halogenation, nitrification, sulfonation, etc., which can modify the molecule and expand its application in organic synthesis and material preparation.

There are various ways to prepare 1% 2C2-dichloro-4-fluorobenzene. One is halogenation. Select an appropriate benzene derivative, use halogen as a reagent, and halogenate it under specific reaction conditions. If benzene is used as the starting material, chlorine atoms are introduced first, and then fluorine atoms are introduced. In the reaction system, the temperature, pressure, and the type and amount of catalyst are regulated. The temperature may vary from tens of degrees Celsius to hundreds of degrees Celsius, and the pressure can be atmospheric or slightly pressurized. Appropriate catalysts, such as iron-based and aluminum-based catalysts, are selected to promote the gradual replacement of hydrogen atoms on the benzene ring by chlorine atoms, and then fluorine atoms are introduced by similar means to obtain 1% 2C2-dichloro-4-fluorobenzene.
The second is the substitution method. Take a benzene compound containing a specific substituent as the substrate and undergo nucleophilic substitution or electrophilic substitution. If the substrate contains a group that can be substituted, such as a halogen atom, a sulfonic acid group, etc., use a fluorine source or a chlorine source as the substitution reagent. Under the catalysis of a suitable solvent and a base or acid The solvent can be selected from polar organic solvents, and the base can be selected according to the reaction requirements. Sodium hydroxide, potassium carbonate, etc., and the reaction parameters are reasonably regulated to achieve the formation of the target product.
The third is the synthesis method. Through the multi-step organic synthesis reaction, starting from simple organic raw materials, through the construction of carbon-carbon bonds and the conversion of functional groups. For example, from simple hydrocarbons, through reactions such as halogenation, addition, and elimination, the benzene ring structure is gradually established, and chlorine and fluorine atoms are introduced in an orderly manner. Each step requires strict control of the reaction conditions to ensure the selectivity and yield of the reaction. After multiple steps of exquisite synthesis, 1% 2C2-dichloro-4-fluorobenzene is obtained.

1% 2C2-dichloro-4-bromobenzene should pay attention to the following things during use:
First, it is related to safety protection. This is a toxic chemical substance. During operation, appropriate protective equipment must be worn, such as protective clothing, gloves, goggles, gas masks, etc., to prevent skin contact, inhalation and accidental ingestion. Because it is irritating to the eyes, skin and respiratory tract, if inadvertent contact, it should be washed with plenty of water immediately. In severe cases, seek medical attention immediately.
Second, pay attention to storage conditions. It should be placed in a cool and well-ventilated place, away from fire and heat sources. It should be stored separately from oxidants and edible chemicals, and should not be mixed to prevent dangerous chemical reactions. The storage area should be equipped with suitable materials to contain the leakage.
Third, pay attention to the operation specifications. The operation should be carried out in the fume hood to ensure that the harmful gases can be discharged in time. When taking it, be sure to weigh it accurately, strictly according to the amount required for the experiment or production, to avoid waste and excessive exposure. After use, the remaining materials and waste should be properly disposed of, not discarded at will, and disposed of in accordance with relevant environmental protection regulations.
Fourth, pay attention to the characteristics of chemical reactions. When participating in various chemical reactions, it is necessary to clarify the reaction conditions, rate and possible products. Due to the presence of chlorine and bromine atoms in its structure, these atoms may undergo substitution, elimination, and other reactions under certain conditions. During operation, it is necessary to strictly control the reaction conditions, such as temperature, pressure, and catalyst, to ensure that the reaction proceeds in the expected direction while preventing side reactions from causing danger.