Industrial Grade 98% 98.5% 99, 99.5% 1,3-Dichlorobenzene CAS 541-73-1

 What is 1,3-Dichlorobenzene?

1,3-Dichlorobenzene, also known as m-dichlorobenzene (m-DCB), is a dichlorobenzene isomer with two chlorine atoms on the benzene ring in the meta (1,3) position. It is an important organic synthesis intermediate in the dye and pesticide industries. Its chemical formula is usually written as:

C6H4Cl2 (CAS No.: 541-73-1, EINECS No.: 208-792-1, molecular weight approximately 147.00)

It is a colorless to slightly yellow transparent liquid at room temperature with an aromatic odor. Its melting point is approximately -24°C, boiling point approximately 172-173°C, relative density approximately 1.288 (20°C), refractive index approximately 1.546, and flash point approximately 63-67°C. m-Dichlorobenzene is slightly soluble in water (approximately 123 mg/L) and readily soluble in organic solvents such as ethanol, ether, and benzene. It has a low vapor pressure but a vapor density approximately five times that of air, and will diffuse along the ground.

From a molecular structure perspective, the two chlorine atoms on the benzene ring of m-dichlorobenzene are located in the meta position (positions 1 and 3). These chlorine atoms both withdraw electrons through inductive effects and donate electrons to the benzene ring through p-π conjugation, endowing the molecule with unique electrophilic substitution reactivity. The electron-withdrawing effect of the two chlorine atoms makes specific positions on the benzene ring (such as position 4) more susceptible to electrophilic substitution reactions such as nitration, sulfonation, and amination—this is the structural basis for m-dichlorobenzene to serve as the starting point for the synthesis of a series of fine chemical intermediates.

m-Dichlorobenzene is stable and does not react with water. It is flammable and when burned produces irritating gasses including hydrogen chloride. It may react violently with active metals such as aluminum. Fire may result from contact with strong oxidizers. It must therefore be stored and used away from sources of fire, oxidizers and active metals.

Non-industrial grade m-dichlorobenzene is designed for testing, scientific research and R&D applications. These are mainly reagent grade (analytical purity, chemical purity) and research grade specifications. The purity is mostly over 99.0% and analytical purity is more than 99.5%. Compared with industrial-grade products, non-industrial-grade products are more concerned with the following indicators:

Purity (content)

Reagent-grade reagents are used for high purity (generally over 99.5% analytical grade) as the purity directly affects the accuracy of analytical results and experiments.

Isomer impurities (o-dichlorobenzene, p-dichlorobenzene)

There are three isomeric dichlorobenzenes. To assure analytical specificity and reaction selectivity, dichlorobenzene reagent grade has a tighter control of the ortho- and para-isomer impurities.

Moisture

Moisture content affects the accuracy of reagent preparation and storage stability and must be strictly controlled.

Very low evaporation residue is required to ensure the purity of the reagent and to avoid impurities that may interfere analysis and reaction.

Color and clarity

The liquid should be clear, from colorless to yellowish and free from mechanical impurities. Abnormal color is usually indicative of oxidation or process impurities.

What are the uses of 1,3-Dichlorobenzene?

1. Synthesis of dye intermediates (core application)

The dye industry is the largest application area for m-dichlorobenzene, accounting for approximately 40% of total consumption. m-Dichlorobenzene is an important intermediate in the synthesis of azo dyes and anthraquinone dyes (such as m-aminophenol and resorcinol), and is subsequently used for dyeing textiles, leather, and paper.

2. Synthesis of pesticide intermediates

The pesticide industry accounts for about 30% of the consumption of dichlorobenzene. It is an important synthetic raw material for fungicides such as propiconazole, difenoconazole, imidacloprid, hexaconazole, eticonazole, and insecticides such as chlorpyrifos, serving the disease control of modern agriculture.

3. Organic synthesis solvents and reaction media

m-Dichlorobenzene is soluble and chemically stable, can be used as a solvent and reaction medium for organic synthesis reactions, to help dissolve reactants, adjust reaction conditions and serve fine chemical production.

4. Fine chemical derivative production

m-Dichlorobenzene can be oxidized by nitration, amination, sulfonation, and other reactions to produce important fine chemicals such as resorcinol, m-aminophenol, m-phenylenediamine, and m-chloroaniline, which are used in downstream industries such as dyes and rubber additives.

5. Environmental monitoring and analysis (core application, reagent grade)

m-Dichlorobenzene is an analytical target for monitoring volatile organic compounds (VOCs) in water, air and soil. Reagent grade m-Dichlorobenzene is used as a standard, calibration reagent and chromatographic reagent for environmental analysis, environmental monitoring and occupational exposure assessment.

6.Scientific research and organic synthesis research (research-level)

m-Dichlorobenzene is an important reagent in the study on the chloroaromatic chemistry and electrophilic substitution reactions. It is used for research on synthetic methodology, catalyst screening and new compound development and serves research in organic chemical chemistry and materials science.

7. Development of methods in analytical chemistry (chromatographic standards)

It is used as a standard substance and retention time reference in the development of gas chromatography and liquid chromatography analytical methods for the establishment of qualitative and quantitative methods for volatile organic compounds.

8. Teaching Experiments and Demonstration

During organic chemistry teaching, m-Dichlorobenzene can be used in experiments such as substitution reactions of aromatic hydrocarbons, separation of isomers, and property comparisons to assist learners in comprehending the reaction rules of chloroaromatic hydrocarbons.

9. Custom synthesis and fine chemical research and development

m-Dichlorobenzene can be used for the custom synthesis of meta-substituted aromatic compounds, serving the research and development of fine chemicals and specialty intermediates, and is a small-batch raw material in the research and development stage.

10. Other Applications

With the increasing demand for environmental and health monitoring, the application scope of non-industrial grade m-dichlorobenzene continues to expand, including in areas such as standard reagent supply, analytical testing services, and environmental emergency monitoring.

It should be noted that non-industrial grade specifications do not mean "risk-free": m-dichlorobenzene is a flammable liquid, its vapor is heavier than air, and inhalation of vapor or skin contact is harmful. Experimental operations must be carried out in a fume hood and protective equipment must be worn. It must be stored away from fire sources, oxidizers and active metals, and must not come into contact with food.

Summarize

1,3-Dichlorobenzene, also known as m-dichlorobenzene (CAS No. 541-73-1), is a colorless to slightly yellow chloroaromatic liquid with a boiling point of approximately 173°C. The two chlorine atoms are located in the meta position of the benzene ring, giving it unique electrophilic substitution reactivity. In daily life, we indirectly encounter it through environmental monitoring reports, scientific research and university laboratories, teaching experiments, occupational health monitoring, and the chemical industry chain. In non-industrial applications, reagent-grade and research-grade m-dichlorobenzene are widely used in volatile organic compound (VOC) environmental monitoring, organic synthesis research, impurity analysis, chromatographic method development, teaching experiments, and custom synthesis, making it a crucial reagent bridging "chloroaromatics" with "detection, research, and development."