Extraction of Gold(III) with Dibutyl Carbitol (BDG)

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Noxx

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Paper on the extraction of dilute solutions of HAuCl4 and HCl using Dibutyl Carbitol.
 

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Compare Dibutyl Carbitol (DBC), aka Butyl Diglyme (BDG), with DiEthyl Malonate (DEM).

DEM, a more recent organic solvent for AuCl3, has a number of benefits over the other more widely popular BDG.

- less soluble in water than BDG.
- denser than water as opposed to BDG which is less dense. The importance of this may not be immediately obvious, but as AuCl3 loads into the organic solvent the densities of BDG and DEM will respectively increase; BDG approaching that of the density of the aqueous fraction (in contrast to DEM). Thus with increasing loading BDG will become increasingly difficult to separate from the aqueous part, but with DEM separation will be faster.
- more pleasant smell.
- etc.
 
Phase inversion is a definite problem with high gold loadings, same thing happens with dihexyl sulfide in Shellsol when loading Pd.
 
I like the phase inversion with BDG. It makes things easier from the operational point of view. Think about a very large decantation funnel.

What are the costs of DEM?. Less water solubility sounds good. Never knew about it, till now. Is there a catalog/procedure like FERRO has for BDG?.
 
Well DEM is already denser. You can scrub with 4M HNO3.

Reduce it with boiling solution of oxalic acid, ferrous sulfate or sulfite (even direct gassing so long as there is some water). Holds 150-170 g/L
 
With BDG, we simply drip the impure solution into tall funnel of DBG till it phase inverts. Then we drain the loaded BDG into other vessel for rinsing and reduction, and then the aqueous phase into a third vessel, and we reload funnel with fresh BDG and open the drip again. Trying to keep things simple, but it's more complicated than it reads.
 
1926 State-of-the-art... hehe.

http://pubs.acs.org/doi/abs/10.1021/j150259a011?journalCode=jpchax.2

I read somewhere that DEM co-extracts Ag (I), so that would be a no-no, for gold extraction purity, over BDG. Who knows really... But if it withstands nitric acid, that could be useful in silver extraction.
 
Research135 said:
1926 State-of-the-art... hehe.

http://pubs.acs.org/doi/abs/10.1021/j150259a011?journalCode=jpchax.2

I read somewhere that DEM co-extracts Ag (I), so that would be a no-no, for gold extraction purity, over BDG. Who knows really... But if it withstands niric acid, that could be useful in silver extraction.
For those that can't download the full article, here is another free source.
Studies on the Chemistry of Gold, Victor Lenher, American chemical society. Journal of physical chemistry 1926, pg 126-129
Mostly talks about extracting gold with ethyl acetate and how well it extracts gold from other chlorides.

Göran
 
I have a drum of EA... to never be touched...
It does strip the gold completely but the smell and solubility in water makes it a nightmare to work with.

DEM is definitely the better choice in my opinion.... Must admit, the Apple/Anise scent is intoxicating to me.
 
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