Ethylene glycol

Ethylene glycol, also known as ethylene glycol, is clear, colorless, syrupy, liquid with sweet taste. It is used as an antifreeze in cooling and heating systems. In organic synthesis, it is used as a protecting group for carbonyl groups. Ethylene glycol is miscible with water, ethanol, acetone, acetic acid, glycerol, pyridine, but difficultly soluble in chloroform, ether, benzene, carbon disulfide, and insoluble in hydrocarbons, chlorinated hydrocarbons, oils, rubber, natural resin. It also can dissolve table salt, zinc chloride, potassium carbonate, potassium chloride, potassium iodide, potassium hydroxide and other inorganic compounds. 

Physical properties about Ethylene glycol are: (1)ACD/LogP: -1.688; (2)# of Rule of 5 Violations:0; (3)ACD/LogD (pH 5.5): -1.69; (4)ACD/LogD (pH 7.4): -1.69; (5)ACD/BCF (pH 5.5): 1.00; (6)ACD/BCF (pH 7.4): 1.00; (7)ACD/KOC (pH 5.5): 2.87; (8)ACD/KOC (pH 7.4): 2.87; (9)#H bond acceptors: 2; (10)#H bond donors: 2; (11)#Freely Rotating Bonds: 3; (12)Index of Refraction: 1.422; (13)Molar Refractivity: 14.384 cm3; (14)Molar Volume: 56.561 cm³; (15)Polarizability: 5.702 10-24cm³; (16)Surface Tension: 43.4129981994629 dyne/cm; (17)Density: 1.097 g/cm³; (18)Flash Point: 108.171 °C; (19)Enthalpy of Vaporization: 50.468 kJ/mol; (20)Boiling Point: 197.539 °C at 760 mmHg ; (21)Vapour Pressure: 0.096000000834465 mmHg at 25°C

Preparation of Ethylene glycol: In industrial, Ethylene glycol can be produced by chlorohydrin method, oxirane hydration and direct ethylene hydration.

1. Chlorohydrin method: Use chlorohydrin as raw material which hydrolyzes in the alkaline medium at 100 °C. It can generate oxirane first, and then hydrolyze to produce Ethylene glycol at pressure of 1.01 MPa.

2. Oxirane hydration: This method has catalytic hydration and direct hydration. The hydration process can be carried out both at atmospheric pressure and under pressure. Ordinary pressure uses a small amount of inorganic acid as catalyst and reacts at 50 ~ 70 °C. The molar ratio of oxirane and water of pressurized hydration is higher in the 1:6 or more, in order to reduce the side effect of generating ether. The reaction temperature is 150 °C and pressure is 147kPa. Ethylene glycol can be obtained by hydration. Now, there is gas-phase catalytic hydration, which uses silver oxide as catalyst, alumina as carrier, and reacts at 150 ~ 240 °C to produce 1,2-ethanediol.

3. Direct ethylene hydration: First, the single-acetate or diacetate can be produced by oxidation from ethylene in the presence of catalyst (such as antimony oxide TeO2, palladium catalyst) in acetic acid solution. Then, Ethylene glycol is obtained by further hydrolysis.

Uses of Ethylene glycol: Ethylene glycol is mainly used to make PET melt, which accounted for 86% of total consumption in 2009, and antifreeze, at around 7% of total consumption. It also has many niche applications due to its cheaply price. Ethylene glycol is used for the manufacture of resins, plasticizers, synthetic fibers, cosmetics, explosives and engine antifreeze. What's more, it is used as raw material for polyester fiber terylene. Ethylene glycol can often be instead of glycerin used as water mixture and solvent in the leather and pharmaceutical industries, respectively. Although the dissolving capacity of Ethylene glycol is strong, it can not be widely used as a solvent. Because it can be easy to be metabolized to produce toxic oxalic acid. Besides, Ethylene glycol is used as a medium for convective heat transfer in, for example, automobiles and liquid cooled computers. It is also commonly used in chilled water air conditioning systems that place either the chiller or air handlers outside, or systems that must cool below the freezing temperature of water. In addition, minor uses of Ethylene glycol include analysis reagents, liquid chromatography eluent, non-aqueous media of electrochemical analysis, and degreaser in electronic industry.

When you are using this chemical, please be cautious about it as the following: Due to the sweet taste of 1,2-ethanediol, children and animals are more inclined to consume large quantities of it than of other poisons. It is harmful if swallowed and it is irritating to eyes. It and its toxic byproducts first affect the central nervous system, then the heart, and finally the kidneys. In case of contact with eyes, please rinse immediately with plenty of water and seek medical advice.

You can still convert the following datas into molecular structure:
(1)Smiles:C(CO)O;
(2)InChI:InChI=1/C2H6O2/c3-1-2-4/h3-4H,1-2H2;

The toxicity data is as follows: