Hi everyone!

I need to purify some GBL from a solution of GBL and Butyl Carbitol (50/50) but i don't know how to proceed. Distillation is not the way since they have very close boiling point ,are very flammable and i don't own a decent distillation apparatus .

I thouht about precipitating GBL as GHB salt by dumping GBL/Bytyl Carbitol solution into a warm bath of EtOH and NaOH but i don't know if it'g going to work.

GBL sould react with NaOH or KOh to form Na-GHB or K-GHB and since neither Na-GHB nor K-GHB are soluble in Eh-OH it should prepipitate and i'll only have to filter it out but i'm not sure if Butyl Carbitol whould interfeer with the reaction.

Butyl Carbitol souldn't react with EtOH neither NaOH since NaOH is used as catalyst in its sinthesys

What do you think ?
Could someone give me some advice ?

PS : Sorry for my bad english !

An accurate, titrated conversion to sodium GHB, would, I believe, be your best bet. :)

Precipitate out, collect, and keep it at about 50 degrees C for about 9000 hours; hopefully evaporating the DGBE.

You do mean 'diethylene glycol butyl ether' by 'butyl carbitol'?

C4H9O(CH2)2O(CH2)2OCH2OH by my reckoning, although I might have got that wrong.

An accurate, titrated conversion to sodium GHB, would, I believe, be your best bet. :)


So do you think is possible to precipitate GHB out of this solution ?


Precipitate out, collect, and keep it at about 50 degrees C for about 9000 hours; hopefully evaporating the DGBE.


9000 hours ? Did you mistyped or did u really mean that ?
I found DBGE very hard to evaporate but 9000 hours are eternity :( .
Do you know if there's some kind of solvent not miscible with DBGE but in which GHB is soluble ?This could be a way .



You do mean 'diethylene glycol butyl ether' by 'butyl carbitol'?

C4H9O(CH2)2O(CH2)2OCH2OH by my reckoning, although I might have got that wrong.

Yes , the solution is 50% DGBE and 50% GBL . I suspect from the safety schedule that H2O could be present.

So do you think is possible to precipitate GHB out of this solution ?



9000 hours ? Did you mistyped or did u really mean that ?
I found DBGE very hard to evaporate but 9000 hours are eternity :( .
Do you know if there's some kind of solvent not miscible with DBGE but in which GHB is soluble ?This could be a way .




Yes , the solution is 50% DGBE and 50% GBL . I suspect from the safety schedule that H2O could be present.

lol 9000 hours, just means a heck of a long time.

think base catylized de-esterfication, koh or naoh will break apart the butyl carbitol leaving you with butanol and glycerin, the glycerin would be your problem

base will brake apart the ester cleavage at the same rate that it creates it if there is any H2O present, and there is

Ah. I didn't know evaporating said DGBE was that difficult to evaporate. Once you've ppted the sodium GHB out and collected it, there should be significantly less DGBE in there, but obviously still enough to remove. I like TheWhiteMan's idea of hydrolysis, but the stoichiometry may be difficult, especially if you don't want to end up with solid NaOH left in your GHB...

Maybe i could be wrong but during my searches i found that in DGBE synthesys NaOH is used as catalyst .

In theory catalyst arent supposed to react with other reactants nor with the reaction product or am i wrong ?.

Maybe in acqueous environment things changes but since i haven't got so much experience in organic chemistry help is very appreciated .

Soda in final product is not a big problem since its precence could be veryfied by ph test and could be neutralized by some weak acid .

solid NaOH left in your GHB...

How about using Sodium bicarbonate to forum Na-GHB precipitate, multiple washes, vac filtrate it and then recrystallize?

Sounds better me...:p

How about using Sodium bicarbonate to forum Na-GHB precipitate, multiple washes, vac filtrate it and then recrystallize?

Sounds better me...:p

Yes , good idea , but what really matters to me is to understand if DGBE could be a problem.
If it doesn't react with NaOH nor with NaHCO3 then i could try precipitate Na-GHB using NaHCO3 in EtOH solution then filtrate ,e vaporate and converting back to GBL.
But if DGBE reacts too with NaHCO3 then this is a huge problem.
Googling around i've not found anything useful about de-esterification of ethers but from what i've learned ethers are quite stable to bases so in theory DGBE should not partecipate to the reaction at all.
Could someone confirm this ?

I think that either NaOH or sodium bicarb would work just fine, and as for solid NaOH left in the final GHB product, that's why god invented PH.

Are we still ignoring base hydrolysis of the ester bond?

^why yes yes they are


I think that the etglycol might form a layer in the bottom of the flask and the butanol could easily be boiled off