Antifreeze in cooling and heating systems. In hydraulic brake fluids and de-icing solutions. Industrial humectant. Ingredient of electrolytic condensers (where it serves as solvent for boric acid and borates). Solvent in the paint and plastics industries. In the formulation of printers' inks, stamp pad inks, ball-point pen ink. Softening agent for cellophane. Stabilizer for soybean foam used to extinguish oil and gasoline fires. In the synthesis of safety explosives, glyoxal, unsatd ester type alkyd resins, plasticizers, elastomers, synthetic fibers (Terylene, Dacron), and synthetic waxes. To create artificial smoke and mist for theatrical uses.
Oral-rat LD50: 4700 mg/kg; Oral-Mouse LD50: 5500 mg/kg.
Inhalation of vapor is not hazardous. Ingestion causes stupor or coma, sometimes leading to fatal kidney injury.
Foam, carbon dioxide, water spray, sand.
Ethylene glycol is a clear, colorless syrupy liquid. The primary hazard is the threat to the environment. Immediate steps should be taken to limit its spread to the environment. Since Ethylene glycol is a liquid Ethylene glycol can easily penetrate the soil and contaminate groundwater and nearby streams.
Skin-rabbit 555 mg Mild; Eyes-rabbit 500 mg/24 hr mild.
Glycol is mainly used as the antifreeze agent for preparation of the automobile cooling systems and the raw material for the production of polyethylene terephthalate (the raw material of polyester fibers and plastics material). It can also be used for the production of synthetic resins, solvents, lubricants, surfactants, emollients, moisturizers, explosives and so on. Glycol can often used as alternative of glycerol and can often be used as hydration agent and solvent in the tanning industry and pharmaceutical industry. Glycol has a strong dissolving capability but it is easily to be oxidized to toxic metabolic oxalic acid and therefore can’t be widely used as a solvent. The ethylene glycol can be supplemented to the hydraulic fluid and can be used for preventing the erosion of oil-based hydraulic fluid on the rubber of the system; the water-based hydraulic fluid with ethylene glycol as a main component is an inflammable hydraumatic fluid and can be applied to the molding machine in aircraft, automobiles and high-temperature operation. There are many important derivatives of ethylene glycol. Low molecular weight polyethylene glycol (mono-uret ethylene glycol, bi-uret ethylene glycol, tri-uret ethylene glycol or respectively called as diethylene glycol, triethylene glycol, tetraethylene glycol) is actually the byproduct during the hydration of ethylene oxide B for preparation of ethylene glycol.
Ethylene glycol is the simplest aliphatic dihydric alcohol with chemical properties of alcohols such as being capable of generating ether, ester, or being oxidized into acid or aldehyde as well as being condensed to form ether or being substituted by halogen. Its reaction with acyl chloride or acid anhydride generally forms di-esters. Under heating in the presence of catalyst (manganese dioxide, aluminum oxide, zinc oxide or sulfuric acid), it can be subject to intermolecular or intramolecular dehydration to form the cyclic ethylene acetals, which can react with nitric acid to generate glycol dinitrate (an explosive). Ethylene glycol is the raw material for production of polyester resins, alkyd resins and polyester fiber. It can also be used as the refrigerant agent for automobile and aircraft engines refrigerant. In 1980, the glycol amount used as refrigerant agent is equal to the amount consumption for producing polyester. In addition, it can also be used for synthesizing polymers such as polyester fibers. Ethylene glycol dinitrate, when used in combination with nitroglycerine can reduce the freezing point of explosives. Ethylene glycol can also be used as the raw material of pharmaceuticals and plastics and high-boiling solvents. Industry applied ethylene as a raw material with first converting it to ethylene oxide and then hydrolyzing to produce ethylene glycol.
This product is of fire and explosion hazards. It is irritating to skin and mucous membrane with inhalation of vapors or skin absorption producing a narcotic effect on the central nervous as well as causing kidney damage. Rat, through oral administration, has a LD50 of 8540 mg/kg. The maximal allowable concentration in the workplace is 5 × 10-6.
This information is edited by Xiongfeng Dai from Chemicalbook.
It is very hygroscopic, and also likely to contain higher diols. Dry it with CaO, CaSO4, MgSO4 or NaOH and distil it under vacuum. Dry further by reaction with sodium under nitrogen, reflux for several hours and distil. The distillate is then passed through a column of Linde type 4A molecular sieves and finally distil under nitrogen, from more molecular sieves. Then fractionally distil it. [Beilstein 1 IV 2369.]
Mixing Ethylene glycol in equal molar portions with any of the following substances in a closed container caused the temperature and pressure to increase: chlorosulfonic acid, oleum, sulfuric acid, [NFPA 1991].
Reagent typically used in cyclocondensation reactions with aldehydes1 and ketones1,2 to form 1,3-dioxolanes.
ChEBI: A 1,2-glycol compound produced via reaction of ethylene oxide with water.
Hazardous characteristics of explosive
Being mixed with air can be explosive.
It is colorless transparent viscous liquid with sweet taste and moisture absorption capability. It is also miscible with water, low-grade aliphatic alcohols, glycerol, acetic acid, acetone, ketones, aldehydes, pyridine and similar coal tar bases. It is slightly soluble in ether but almost insoluble in benzene and its homologues, chlorinated hydrocarbons, petroleum ether and oils.
1. Direct hydration of ethylene oxide is currently the only way for industrial-scale production of ethylene glycol. Ethylene oxide and water, under pressure (2.23MPa) and 190-200 ℃ conditions, and can directly have liquid-phase hydration reaction in a tubular reactor to generate ethylene glycol while being with byproducts diethylene glycol, tripropylene ethylene gl]ycol and multi-uret poly ethylene glycol. The dilute ethylene glycol solution obtained from the reaction further undergoes thin film evaporator condensation, and then dehydration, refinement to obtain qualified products and by-products. 2. sulfuric acid catalyzed hydration of ethylene oxide; ethylene oxide can react with water, in the presence of sulfuric acid as the catalyst, at 60-80 ℃ and pressure of 9.806-19.61kPa for hydration to generate ethylene glycol. The reaction mixture can be neutralized by liquid alkaline and evaporated of the water to obtain 80% ethylene glycol, and then distilled and concentrated in distillation column to obtain over 98% of the finished product. This method is developed in early time. Owing to the presence of corrosion, pollution and product quality problems, together with complex refining process, countries have gradually discontinued and instead change to direct hydration. 3. Direct ethylene hydration; directly synthesize ethylene glycol from ethylene instead of being via ethylene oxide. 4. dichloroethane hydrolysis. 5. Formaldehyde method.
Industrial preparation of ethylene glycol adopts chlorine ethanol method, ethylene oxide hydration and direct ethylene hydration with various methods having their characteristics, as described below.
Take chloroethanol as raw materials for hydrolysis in alkaline medium to obtain it. The reaction is carried out at 100 ℃. First generate ethylene oxide. Then pressurize at 1.01 MPa pressure to obtain ethylene glycol.
Ethylene oxide hydration
Hydration of ethylene oxide contains catalytic hydration and direct hydration. The hydration process can be carried out under either normal pressure or under compression. Normal pressure method generally take a small amount of inorganic acid as catalyst for reaction at 50~70 ℃.
Pressurized hydration had a high demand for the molar ratio of ethylene oxide over water which is higher than 1:6, to reduce the side reaction of producing the ether with the reaction temperature being at 150 °C and the pressure being 147kPa with hydration generating ethylene glycol.
There are currently gas phase catalytic hydration with silver oxide being the catalyst and the alumina oxide being the carrier for reaction at 150~240 ℃ to generate ethylene glycol.
Direct hydration of ethylene
Ethylene, in the presence of catalyst (e.g., antimony oxide TeO2 with palladium catalyst) can be oxidized in acetic acid solution to generate monoacetate ester or diacetate ester with further hydrolysis obtaining the ethylene glycol.
The above several methods takes ethylene oxide hydration as good with simple process and is suitable for industrialization.
Flammability and hazard characteristics
It is combustible in case of fire, high temperature and strong oxidant with burning releasing smoke irritation.
Poisoning and first aid
This product is of low toxicity. Rat LD50: 5.5ml/kg~8.54ml/kg. People who is subject to oral administration by once has a LD50 of 80g~100g. The plasma concentration of ethylene glycol is 2.4g/L and can cause acute renal failure. It can be absorbed through the digestive tract, respiratory tract and skin. It can be discharged from the kidney in the form of prototype or ethanedioic acid (oxalate) from through oxidation. Glycol, after being oxidized into carbon dioxide, can be discharged from the respiratory tract.
Although ethylene glycol has a high toxicity but its volatility is small. Therefore, it is unlikely that the inhalation of it during production can cause severe poisoning. Inhalation poisoning is manifested as blurred consciousness, nystagmus and urine containing protein, calcium oxalate crystals and red blood cells. Oral toxicity in clinical practice can be divided into three stages: the first stage is mainly the central nervous system symptoms, such as the performance of ethanol poisoning; the second phase of the main symptoms mainly include shortness of breath, cyanosis, and various manifestations of pulmonary edema or bronchopneumonia; at the third stage, there may be significant renal disease, low back pain, kidney area percussion pain, renal dysfunction, proteinuria, hematuria, urine containing calcium oxalate crystals, as well as oliguria, anuria and even acute renal failure.
Patients mistakenly take it should be subject to the treatment based on the general principles of first aid for oral poisoning and can be given 600 mL of 1/6 mol of sodium lactate solution and 10 mL of 10% calcium gluconate through intravenous infusion. Patients of severe poisoning can subject to treatment of artificial kidney dialysis.
Container of ethylene glycol should have "toxic agents" mark. The product, upon heating, should be sealed, vented to prevent inhalation of the vapor or aerosol. Avoid long-term direct skin contact with the product.
Ethylene glycol is combustible.
Ethylene glycol,CH20HCH20H, also known as glycol,ethylene alcohol, glycol alcohol, and dihydric alcohol, is a colorless liquid. It is soluble in water and in alcohol. Ethyleneglycol has a low freezing point,-25°C (-13 OF), and is widely used as an antifreeze in automobiles and in hydraulic fluids. It is used as a solvent for nitrocellulose and in the manufacture of acrylonitrile, dynamites, and resins.
Treasury: ventilation, low-temperature and dry.
TWA 60 mg/m3; STEL 120 mg/m3.