Perchlorethylene, Perchloroethylene, PER, PCE, PERK, PERC, Dowper, Perchlorethylene, carbon dichloride, 127-18-4

Perchlorethylene, Perchloroethylene, PER, PCE, PERK, PERC, Dowper, Perchlorethylene, carbon dichloride, 127-18-4

CAS: 127-18-4

Molecular Formula: C2Cl4

Names and Identifiers

Physico-chemical Properties

Risk and Safety

Upstream Downstream Industry

Nature

Open Data Verified Data

• colorless transparent liquid with an odor similar to ether. Can dissolve a variety of substances (such as rubber, resin, fat, AICl3, S, I2, HgCI2). Non-combustible. Sexual stability. In the absence of air, moisture and catalyst, heating to 500 °c was stable. Resistant to hydrolysis. Relative density (d20) 1.6227. Boiling at 121 °c. The freezing point was about -22.0 °c. Refractive index (n ~ 0)1. 50547. No flash point. With ethanol, ether, chloroform, benzene miscibility. Dissolve in about 10000 times the volume of water.
• long-term decomposition in the presence of light, water, oxygen into trichloroacetaldehyde and phosgene, corrosive to metals. An amine or phenol derivative of (10 to 500)× 10 -6 is generally added as an anti-decomposing agent.

Preparation Method

ethylene method

This method can produce trichloroethylene and tetrachloroethylene, divided into the following two methods.

1. Direct chlorination: Ethylene and chlorine are reacted in 1,2-= ethyl chloride solution containing FeCb catalyst at 280~450 °c to produce 1,2-= ethyl chloride, further chlorination into trichloroethylene and tetrachloroethylene, after distillation, respectively, with NH3 neutralization, washing, drying, that is to obtain the finished product.
2. oxychlorination method with ethylene and chlorine addition to generate 1,2 dichloroethane, 1,2-= ethyl chloride and chlorine, oxygen in CuCLz and KCL as catalyst and 425 deg C, under the condition of 138 ~ 207kPa, the oxychlorination reaction was carried out, and the product was cooled, washed with water, dried and distilled to obtain a high purity product.

oxidation of hydrocarbons

A mixture of hydrocarbons containing methane, ethane, propane, propylene and the like is chlorinated and pyrolyzed at 50~500 ° C. To obtain a mixture of chlorinated hydrocarbons, which is fractionated and separated into various products.

acetylene method

acetylene and chlorine are heated and chlorinated to produce 1,1,2,2 tetrachloroethane, and trichloroethylene is obtained by dehydrochlorination with alkali, pentachloroethane is generated by chlorination, and then Tetrachloroethylene is obtained by dehydrochlorination with alkali. Due to the high price of acetylene, has been gradually replaced by the ethylene method.

Use

can be used as a solvent, dry cleaning agent, animal and vegetable oil extractant, fire extinguishing agent and smoke agent. It can also be used for the synthesis of trichloroacetic acid and fluorine-containing organic compounds.

Safety

toxic, is a central nervous system inhibitors, inhalation, swallowing or absorption through the skin can cause a strong harm, such as Head Pain, trembling, Vomit, severe loss of consciousness in the end to death. Irritating to the eyes and skin. Contact should be immediately washed with water. The maximum allowable concentration in air is 100 × 10-6. Operators exposed to higher concentrations of tetrachloroethylene should wear gas masks and protective gloves. Its packaging and storage see trichloroethylene.

Nature

Use

• In industry, tetrachloroethylene is mainly used as solvent, organic synthesis, metal surface cleaner and dry cleaning agent, desulfurizer and heat transfer medium. Medically used as an insect repellent. It is also an intermediate for the production of trichloroethylene and fluorine-containing organic matter. General residents may be exposed to low concentrations of tetrachloroethylene through the atmosphere, food and drinking water.
• Tetrachloroethylene has good solubility for many inorganic and organic compounds, such as sulfur, iodine, mercury chloride, aluminum trichloride, fat, rubber and resin, etc. This solubility is widely used as metal degreasing cleaning agent, paint remover, dry cleaning agent, rubber solvent, ink solvent, liquid soap, degreasing of high-grade fur and feathers; Tetrachloroethylene is also used as deworming (hookworm and.
• Tetrachloroethylene is also an intestinal repellent, which is effective in treating hookworm infection and killing hookworm and American hookworm. However, side effects such as dizziness, headache, nausea, drowsiness and drunkenness can occur. Generally, use its capsules to swallow on an empty stomach, and avoid oil and alcohol during the medication to avoid poisoning. It is highly toxic to the liver and central nervous system, has strong irritation to the digestive tract, and can cause anemia, so it is now used less.
• Tetrachloroethylene dry cleaning is still dominant in the world. The use of tetrachloroethylene can clean clothes efficiently and safely. It has the characteristics of low solvent consumption and emission, can be recycled repeatedly, and has good safety performance. Structurally speaking, due to the chlorine atoms in it, tetrachloroethylene is not easy to burn, and it has neither flash point nor explosion; but when other substances are burned, irritating and harmful gases can be produced, so do not contact open flames and 150 ℃ High-temperature substances above; higher density than air, heavier than air, will be deposited on the ground; heavier than water and moisture layer will sink in the lower layer; low surface tension, easy to contact with clothing and stains; KB value is high, can easily dissolve grease dirt.

Security information

protective measures

The production equipment should be airtight, and the operator should wear protective work clothes and protective glasses to prevent skin and eyes from contacting it. If the work clothes may be contaminated, they should be replaced every day. Permeable work clothes, if wet or contaminated, are quickly removed.

medical monitoring

The skin, liver and kidney functions and the central nervous system should be examined during physical examination.

breath analysis is helpful to assess exposure to tetrachloroethylene. Attention should be paid to the history of liver, kidney and neurological diseases of workers before employment.

determination method

Determination in air: adsorption with activated carbon, CS2 treatment, gas chromatography analysis.

Determination in water

First clean with inert gas, followed by gas chromatography or gas-mass spectrometry for halide specific detection.

store

packed in iron drums. Store in a cool, dry and well ventilated place. Stay away from any area where there is a risk of violent fire.

shipping requirements

Organic drugs. Hazard code number: 84009, the container must be marked with "drugs" during transportation.

Preparation

1. ethylene method

this method can coproduce trichloroethylene and tetrachloroethylene, which are divided into the following two methods. A. Direct chlorinated ethylene and chlorine are reacted in a solution of 1,2-dichloroethane containing FeCl3 catalyst at 280-450 ℃ to generate 1,2-dichloroethane, which is further chlorinated to trichloroethylene and tetrachloroethylene. After distillation, it is neutralized, washed and dried with NH3 respectively to obtain the finished product. B. oxychlorination is carried out by the addition of ethylene and chlorine to produce 1, 2-dichloroethane, 1, 2-dichloroethane, chlorine and oxygen are subjected to oxychlorination reaction under the conditions of CuCl2 and KCl as catalysts and 425 ℃ and 138-207kPa. The product is cooled, washed with water, dried and then distilled to obtain high purity product.

2. Hydrocarbon oxidation method

the hydrocarbon mixture containing methane, ethane, propane, propylene, etc. is chlorinated and pyrolyzed at 50-500 ℃ to obtain the mixture of chlorinated hydrocarbons, which is separated into various products after rectification.

3. acetylene method

Acetylene and chlorine are heated and chlorinated to produce 1,1,2,2, 2-tetrachloroethane. Hydrogen chloride is removed with alkali to obtain trichloroethylene, which is then chlorinated to produce pentachloroethane, and then hydrogen chloride is removed with alkali to obtain tetrachloroethylene. Because of the high price of acetylene, it has been gradually replaced by the ethylene method.

Introduction

Perchlorethylene (chemical formula: C2Cl4) is a colorless liquid with a special smell. It is an environmentally stable organic compound that does not burn easily, but can react violently with oxygen, strong oxidants, and heat.

Perchlorethylene are mainly used in industrial production and have a wide range of applications. It is one of the important raw materials of polyvinyl chloride (PVC), which is used to make plastics, pipes, insulation materials and coatings. In addition, Perchlorethylene can also be used as a solvent for degreasing, metal cleaning and chemical synthesis processes.

Hydrogenation of chlorinated hydrocarbons is usually used to prepare Perchlorethylene. First, 1,2-dichloroethane is obtained by chlorinating ethylene using chlorine gas. Then, under high temperature and high pressure conditions, 1,2-dichloroethane reacts with chlorine to form Perchlorethylene. The entire process needs to be carried out under strictly controlled environmental conditions to ensure safety and yield efficiency.

The Perchlorethylene needs to pay attention to its safety information when using it. It is a harmful substance that is irritating and may cause irritation and damage to the skin, eyes and respiratory tract. Immediately after contact, rinse thoroughly with water and seek medical help. In addition, Perchlorethylene vapors are flammable and should be kept away from open flames and high temperature sources. During use and storage, relevant safety procedures should be observed to ensure proper ventilation and protective measures.

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Perchloroethylene poisoning

The harm of vinyl chloride to humans is that it can be absorbed through the respiratory tract, digestive tract and skin poisoning.

after tetrachloroethylene enters the human body, its accumulation in the body is limited, about 98% is discharged through the lungs, and only 2% changes. It is mainly converted into trichloroacetic acid and trichloroethanol, which are excreted in urine. This product is discharged from the body very slowly. After inhaling the vapor with a concentration of 2.7mg/L for 3.5h, it can be measured after 2 weeks, and the average 62% of this product is retained in the lung. The concentration is 1.3mg/L, and equilibrium can be reached after 3 hours.

The toxicity of tetrachloroethylene is lower than that of trichloroethylene, and its anesthetic effect is weaker. It mainly inhibits the central nervous system. The liver and kidney are less toxic, and it is irritating to the eyes, nose, throat and pharynx. Although it does not burn, this product can emit highly toxic and irritating smoke during a fire. The allowable concentration in the air is 100ppm in China and 50ppm (335mg/m3) in the United States.

harmful effects and poisoning symptoms

Re-contact with tetrachloroethylene liquid can cause dry skin and dermatitis. High concentration of vapor can stimulate eyes and nose.

Acute exposure to higher concentrations of tetrachloroethylene can cause depression in the central nervous system, presenting symptoms of anesthesia, and severe liver injury and even death. Exposure to 300~1,000ppm vapor can cause misjudgment. Exposure to high concentrations can cause dizziness, lethargy, loss of consciousness and even death. The signs and symptoms caused by excessive exposure mainly include discomfort, dizziness, headache, increased sweating, fatigue, faltering gait, and mental retardation. However, these signs and symptoms usually decrease rapidly after reaching the fresh air in the open air.

treatment of poisoning

if this chemical enters the eye, immediately rinse with water; If it comes into contact with the skin, wash it quickly with soap and water; If someone inhales a large amount, immediately move away from the scene to fresh air, and if necessary, carry out artificial respiration. If swallowed, take a large amount of saline, induce vomiting, gastric lavage, severe cases do not cause vomiting, should be sent to the hospital immediately for treatment.

Contacts should leave the scene immediately. Patients with irritation symptoms need to rest quietly, carry out necessary examination and treatment, and observe for 24 hours. Mainly symptomatic treatment.

Acute poisoning patients should stay in bed. The principles of first aid measures and symptomatic treatment are the same as those of internal medicine. For those with coma, heartbeat and respiratory arrest, rapid brain, heart, and lung resuscitation; pay attention to symptomatic treatment.

glucocorticoids can be used appropriately in patients with severe tetrachloroethylene poisoning.

pay attention to protect liver and kidney functions. Avoid adrenaline.

Reference: Editor-in-Chief Ding Baogan. A complete collection of poisoning prevention and control. Zhengzhou: Henan Science and Technology Press. 2006. Page 387.

Safety protection

Fire suppression measures

In the event of a fire, use mist water to keep the container exposed to the fire cool, and use mist water to flush the spill away from the fire.

recommended waste disposal method

Incineration; Incineration is preferable after mixing with other flammable fuels. Attention must be paid to ensure complete combustion to prevent phosgene generation. In order to remove the hydrogen halide acid produced, it is necessary to install an acid scrubber. Another alternative method is to recover tetrachloroethylene from the exhaust gas and reuse it.

Use

Security information

Nature

Perchloroethylene is also called perchloroethylene. In terms of molecular structure, it is a compound formed by replacing all hydrogen atoms in ethylene with chlorine. It was first produced in 1821 when Faraday pyrolyzed hexachloroethane. Colorless transparent liquid. It has an ether-like smell. Non-combustible. Relative molecular mass 165.85. Relative density 1.6220. Melting point -22.7 ℃. Boiling point 121.2 ℃, 33.2 ℃(4.000 × 103 Pa). Refractive index 1.5055. Viscosity 0.839mPa · s(20 ℃). Vapor pressure (× 103Pa):5.466(40 ℃), 13.865(60 ℃), 30.131(80 ℃), 58.128(100 ℃). Tetrachloroethylene is insoluble in sugar, glycerol and protein, slightly soluble in water (0.015 at 25 ℃), and is miscible with ethanol, ether, chloroform, benzene and chlorine organic solvents. Not hydrolyzed. In the presence of no air, no moisture and no catalyst, it is still stable even when heated to 500 ℃. Tetrachloroethane can be generated during hydrogenation. Hexachloroethane is produced when chlorinated. Tetrachloroethylene can also react with bromine to form monobromo trichloro or dibromo dichloro compounds. Under the action of a catalyst, it can also react with hydrogen fluoride. In the presence of light, air and water for a long time, it slowly decomposes into trichloroacetaldehyde and phosgene, and corrodes iron, aluminum, zinc and other metals, which can be inhibited by adding stabilizers. If activated carbon is present, it is heated to 700 ℃ to decompose into benzene hexachloride and ethane hexachloride. Perchloroethylene can be oxidized by strong oxidants. Perchloroethylene can react violently with barium powder, beryllium powder, lithium chips, dinitrogen tetroxide, and sodium hydroxide. Tetrachloroethylene is toxic and is a central nervous system inhibitor that can cause headaches, nausea, vomiting, and even coma. Mice were LD508850mg orally/kg. The maximum allowable concentration in the workplace is 100 × 10-6.