# What is the mechanism of the uncatalysed epoxide opening with alcohols?

Ethoxylation is an industrial process in which ethylene oxide is added to alcohols and phenols to turn it into a surfactant.

How does the reaction proceed?

The answer to the question "Do epoxide rings react with bases?" regarding epoxide rings reacting with bases does not include alcohols, and does not answer my question.

• Does this answer your question? – Klaus-Dieter Warzecha May 4 '15 at 9:34
• @KlausWarzecha Maybe that reaction might be one of the reaction steps. I don't know. – Larry May 4 '15 at 10:02
• @Martin So intead of CH3O- of that answer, lp of CH3OH will attack? And Eka gave me a link - chemstations.com/content/documents/technical_articles/ethox.pdf and it is different. – Larry May 4 '15 at 16:44
• The link you provided has does not explain anything about the mechanism and it is about a base catalysed reaction. – Martin - マーチン May 5 '15 at 8:51
• @Larry The alcoholate, because it is deprotonated, has three lone pairs, one of them, the HOMO, will attack in a nucleophilic manner. An alcohol still has two lone pairs, and one of the is the HOMO, which will make the nucleophilic attack. The whole process might be slower, as it is less nucleophilic, but you can assume the mechanism to be almost identical. – Martin - マーチン May 15 '15 at 3:21

Because of its special chemical struture Ethyelene oxide (EO) is highly reactive material thus easily participate in chemical reactions which includes polymerization. Mechanism of opening of EO's ring in acidic and alkaline medium is given below

If you see in both cases a molecule with alcoholic group ($\ce{-OH}$) is formed.If the epoxyethane is in excess, the reaction can continue and could lead to polymerization.

A good example is the reaction between EO and water

As explained in wikipedia ethoxylation is an industrial process to make surfactant from EO. Surfactants are chemical molecule which contain both hydrophobic groups (their tails) and hydrophilic groups (their heads).

The end result of reaction with EO and alchol is a long chain molecule with these hydrophobic ($\ce{-R}$) and hydrophilic ($\ce{-OH}$) group

• In the first image, from where did the H+ and OH- come from? Where did they alcohol go. – Larry May 4 '15 at 11:01
• It just shows reaction environment H+ from acid (HCl, H2SO4..etc) and OH- from base (NaOH etc) see this link – Eka May 4 '15 at 11:14
• Where did the alcohol go? – Larry May 4 '15 at 13:26
• @larry See the alcohol reaction here R-OH is the alcohol see this example – Eka May 4 '15 at 13:49
• But that has an acid and alcohol. Epoxide and alcohol? – Larry May 4 '15 at 13:54