[Chemical Knowledge]：The nature, use, upstream and downstream raw materials, storage methods, and the harmfulness of picric acid.

Picric acid properties

Chemical properties
Picric acid (Picric acid), chemical name is 2,4, 6-trinitrophenol (Trinitrophenol), molecular formula C6H2(NO2)3OH, molecular weight of 229.10. Picric acid is a yellow crystalline solid with a high melting point (122-123°C) and high density (1.763g/cm³). It is easily soluble in hot water and organic solvents, such as ethanol, ether, benzene and acetone, and has low solubility in cold water. Picric acid has a strong acidity, its pKa is about 0.38, showing a strong acidic characteristics.

Physical Properties
The physical properties of picric acid give it unique advantages in different applications. Its flash point is 150°C, ignition point is 300°C, and lower explosive limit is 0.6g/cm³. Due to its high energy density and strong explosiveness, picric acid requires special care in handling and use. Nevertheless, it is still widely used in chemical and military fields.

Use of picric acid

Military use
One of the best known uses of picric acid is in the military industry. It is a traditional explosive commonly used in the manufacture of explosives, detonators and ammunition. Because of its strong explosive and stability, picric acid was widely used in the first and second world wars. However, modern military technology has gradually used more stable and safe alternatives, but picric acid still plays a role in certain military applications.

dyestuff industry In the dye industry, picric acid is used as a yellow dye, especially for dyeing protein fibers such as wool and silk. It is also an intermediate for many dyes, and can generate a variety of other dyes, such as bitter amine dyes, through chemical reactions.

Medical field
Picric acid also has some applications in the medical field, mainly as a topical disinfectant and antiseptic. Due to its antibacterial properties, picric acid can effectively prevent bacterial infections. In the past, it has also been used to treat some skin diseases, but due to its toxicity and irritation, its medical use has been greatly reduced.

Picric acid upstream and downstream raw materials

Upstream Feedstock
The production of picric acid involves a variety of chemical raw materials. The main upstream feedstocks include phenol and concentrated nitric acid. In the production process, phenol is first nitrated to produce nitrophenol, and then further nitrated to produce picric acid. This process is usually carried out in an acidic medium, and the reaction conditions need to be strictly controlled to ensure the purity of the product and the safety of the reaction.

Downstream Products
The downstream products of picric acid mainly include various types of explosives, dyes and pharmaceutical products. The main products in the field of explosives include picric acid explosives, picrate salts and detonators. In terms of dyes, picric acid can be further converted to bitter amines, which are important intermediates for the synthesis of many dyes. In the field of medicine, picric acid and its derivatives are still used in certain antiseptic and disinfectant formulations, although their use has decreased.

Picric acid storage method

Storage Environment Requirements
Due to the explosive nature and high sensitivity of picric acid, its storage requires special attention. Should be stored in a cool, dry, well-ventilated environment, away from fire and heat sources. The temperature of the storage environment should be kept below 20°C and the relative humidity should be below 50% to avoid the risk of decomposition or explosion caused by moisture.

Packaging and protective measures The picric acid should be stored in sealed containers with strong corrosion resistance, such as glass bottles or special plastic containers. The container shall be clearly marked with its danger and precautions for use. The storage area should be equipped with explosion-proof equipment and fire extinguishing equipment, and the staff should wear protective equipment, such as gloves and goggles, to prevent direct contact and inhalation of picric acid dust.

Safety management measures During the storage of picric acid, strict safety management measures should be implemented. Regularly check the tightness and integrity of the storage container to avoid damage or leakage of the container. The open flame and smoking shall be prohibited in the storage area, and the entry and exit of personnel shall be strictly controlled. The storage site should be equipped with monitoring equipment and alarm system to take prompt measures in case of emergency.

picric acid safety

Toxicity
Picric acid has a certain toxicity, the human skin, eyes and respiratory system irritation. Prolonged exposure to or inhalation of picric acid dust may cause headache, nausea, and skin inflammation. Ingesting large amounts of picric acid can cause more serious symptoms of poisoning, such as vomiting, abdominal pain, liver and kidney damage, and even life-threatening.

emergency treatment
When handling and using picric acid, an emergency treatment plan should be prepared. In the event of a leak, evacuate immediately, cover the leak with sand or other non-combustible materials, and clean it up under well-ventilated conditions. Skin in contact with picric acid should be rinsed immediately with plenty of water, eye contact should be rinsed with saline and medical attention. Those who inhale picric acid dust should be transferred to fresh air immediately, and those who are serious should be sent to a doctor for first aid.

Summary

As an important chemical, picric acid has a wide range of applications and important economic value. Its unique chemical and physical properties make it play an important role in the fields of military, dyes and medicine. Due to their explosiveness and toxicity, special care is required during production, storage and use to ensure strict safety management and protective measures. Through the detailed analysis of the properties, uses, upstream and downstream raw materials and storage methods of picric acid, this important chemical can be better understood and utilized to provide strong support for the development of related industries.