, - dinitroxyethene (dinitroglycol) Dehydration reaction Ethyleneglycol undergoes dehydration reaction under different conditions to form different products. . When heated to 773K, it forms epoxides. K - H O Oxirane ( , - epoxyethane ethane - , - diol .
When heated with dilute sulphuric acid (or) anhydrous ZnCl under pressure in a sealed tube, it gives acetaldehyde. anhydrous ZnCl - H O CH CHO Ethanal Vinylalcohol ethenol ethane- , - diol ( Tautomerisation XII U11-Hydroxy XII U11-Hydroxy - - - - . When distilled with Conc. H SO , glycol forms dioxane H O HO Con H SO -2H O ethane - , - diol , - dioxane Oxidation of glycol On oxidation, glycol gives a variety of products depending on the nature of oxidizing agent and other reaction conditions.
i) When nitric acid (or) alkaline potassium permanganate is used as the oxidizing agent, the following products are obtained. CH OH CH OH CHO CH OH [O] [O] [O] [O] COOH CH OH COOH CHO COOH COOH [O] CHO CHO Glycolic acid Glyoxalic acid Oxa ic acid [O] Glyoxal Glycolicaldehyde l -hydroxy ethanal -hydroxy ethanoic acid formyl methanoic acid ethane- , dioic acid ethane- , -dial ii) Oxidation of glycol with periodic acid Ethylene glycol on treatment with periodic acid gives formaldehyde. This reaction is selective for vicinal , – diols and it proceeds through a cyclic periodate ester intermediate. CH OH CH OH + HIO H + /H O I H - C - H H - C - H + HIO Formaldehyde XII U11-Hydroxy XII U11-Hydroxy - - - - Reaction of Glycerol Nitration: Glycerol reacts with concentrated nitric acid in the presence of concentrated sulphuric acid to form TNG (nitroglycerine).
CH + HO NO CH NO NO NO Con H SO -3H O , , - trinitroxy propane Propan - , , - triol glycerol Dehydration When glycerol is heated with dehydrating agents such as Con