Views: 262 Author: Vickey Publish Time: 2023-06-08 Origin: Site
A vicinal diol, ethylene glycol (also known as ethane-1,2-diol), is an organic molecule having the chemical formula (CH2OH)2. It is primarily utilized for two things: as a raw material to make polyester fibers and as an ingredient in antifreeze compositions. It is a thick liquid that has no flavor, color, or odor. Despite having a pleasant flavor, ethanol is harmful in large quantities. In space, this molecule has been seen.
Ethylene glycol is produced from ethylene (ethene), via the intermediate ethylene oxide. Ethylene oxide reacts with water to produce ethylene glycol according to the chemical equation:
C2H4O + H2O → HO−CH2CH2−OH
This reaction can happen at a neutral pH at high temperatures, or it can be catalyzed by either acids or bases. The biggest ethylene glycol yields happen when there is a lot more water present and the pH is acidic or neutral. 90% ethylene glycol yields are feasible in these circumstances. The oligomers diethylene glycol, triethylene glycol, and tetraethylene glycol are the main byproducts.The separation of these oligomers and water is energy-intensive. About 6.7 million tonnes are produced annually.
The main applications of ethylene glycol are the production of polyester, polyester resin, hygroscopic agents, plasticizers, surfactants, synthetic fiber, cosmetics, and explosives. It is also used as a dye, ink solvent, engine antifreeze preparation agent, gas dewatering agent, manufacturing resin, and as a fiber, leather, and adhesive wetting agent. The synthetic resins PET, PET fiber grade, or polyester fiber, PET bottle sheet grade, and alkyd resin, glyoxal, which is also used as antifreeze, may all be produced by ethylene glycol. It is used for transportation of industrial cooling, also known as the cooling agent, and as water as a condensate at the same time, in addition to being used as antifreeze for cars.
In the synthesis of organic molecules, ethylene glycol serves as a protective group for carbonyl groups. When an acid catalyst, such as p-toluenesulfonic acid (BF3Et2O), is used to react an aldehyde or ketone with ethylene glycol, the resulting 1,3-dioxolane is resistant to bases and other nucleophiles. After that, further acid hydrolysis can be used to remove the protective group from the 1,3-dioxolane. In this instance, ethylene glycol with a modest yield of p-toluenesulfonic acid was used to preserve isophorone. Azeotropic distillation was used to remove water in order to tip the equilibrium to the right.
With an oral LDLo of 786 mg/kg for humans, ethylene glycol has a moderately high mammalian toxicity when swallowed, about on par with methanol. The primary risk is brought on by its sweet flavor, which might draw kids and animals.Ethylene glycol, when consumed, breaks down into harmful oxalic acid and glycolic acid.
The central nervous system is the first organ to be impacted by it and its toxic metabolites, followed by the heart and kidneys. If left untreated, ingesting a substantial quantity is lethal. There are antifreeze products for use in automobiles that employ propylene glycol instead of ethylene glycol. Since propylene glycol is not as tasty and is metabolized by the body into lactic acid during exercise and metabolism, it is usually thought to be safer to use.
A chemical with a rapid rate of synthesis, ethylene glycol decomposes in the air in approximately 10 days and in water or soil in a few weeks. When ethylene glycol-containing goods are dispersed into the environment, especially when they are employed at airports to de-ice runways and aircraft, ethylene glycol is released into the environment. Ethylene glycol doesn't appear hazardous at extended low doses, but at almost deadly dosages (1000 mg/kg per day), it behaves as a teratogen.
