Views: 9 Author: Site Editor Publish Time: 07-01-2022 Origin: Site
Properties
Melting point: -13℃(lit.)
Boiling point: 195-198℃
Density: 1.113g/mLat25℃(lit.)
Vapor density: 2.1(vChemicalbooksair)
Vapor pressure: 0.08mmHg(20℃)
Refractive index: n20/D1.431(lit.)
Flash point: 230℉
Storage conditions: 2-8℃
Introduction
Ethylene glycol is also known as glycol, 1,2-ethylene glycol, or EG for short. The chemical formula is (CH2OH)2, which is the simplest diol. Ethylene glycol is a colorless, odorless, sweet-tasting liquid with low toxicity to animals. Ethylene glycol can be miscible with water and acetone, but has low solubility in ethers. Due to its low molecular weight and active nature, it can react with esterification, etherification, alcoholization, oxidation, acetalization and dehydration. Similar to ethanol, it can mainly react with inorganic or organic acids to form esters. Generally, only one hydroxyl group reacts first. By increasing the temperature and increasing the amount of acid, both hydroxyl groups can form esters. If it reacts with nitric acid mixed with sulfuric acid, dinitrate is formed. Acid chloride or acid anhydride easily makes two hydroxyl groups form an ester. Ethylene glycol is heated under the action of a catalyst (manganese dioxide, aluminum oxide, zinc oxide or sulfuric acid) to cause intra- or intermolecular water loss.
Uses
Mainly used to make polyester, polyester, polyester resin, moisture absorbent, plasticizer, surface active agent, synthetic fiber, cosmetics and explosives, and as a solvent for dyes, inks, etc., to prepare engine antifreeze, gas dehydrating agent , It can also be used as a humectant for cellophane, fiber, leather and adhesives to make resin. It can produce synthetic resin PET, fiber-grade PET or polyester fiber, and flake-grade PET for making mineral water bottles. It can also produce alkyd resin, glyoxal, etc., and can also be used as an antifreeze. In addition to being used as an antifreeze for automobiles, it is also used for the transportation of industrial refrigeration. It is generally called a refrigerant carrier. At the same time, it can also be used as a condensing agent like water.
Preparation
The ethylene oxide hydration method has direct hydration method and catalytic hydration method. The hydration process can be carried out under normal pressure or under pressure. Normal pressure hydration generally uses a small amount of inorganic acid as a catalyst, and the reaction is carried out at 50-70°C. Direct hydration of ethylene oxide is a more mature production method for industrial-scale production of ethylene glycol. Ethylene oxide and water are ethylene glycol produced by direct liquid phase hydration in a tubular reactor under pressure (2.23MPa) and 190~200 ℃. At the same time, the by-products are diethylene glycol and triethylene glycol. Glycols and polycondensed polyethylene glycols.