Butyl diglyme storage's safety

[isma_123gold]

Hello. As I'm very interested in learning everything about refining, I have been reading and learning about chemistry in general—although the chemistry branch we need is mostly inorganic, some organic chemistry knowledge can be very helpful in these operations.

Butyl diglyme is an organic compound used as a solvent for chloroauric acid (HAuCl₄) in a process for obtaining high purity gold, it's chemical formula is C₁₂H₂₆O₃. It can also be called diethylene glycol dibutyl ether.

It's a well known topic in organic chemistry that ethers can form upon prolonged storage explosive organic peroxides (due to light and oxygen from the enviroment), one example is another solvent called diethyl ether that can form diethyl ether peroxide.

And as butyl diglyme is also an ether, it is not a weird assumption that it could form dangerous peroxides upon prolonged exposure. It has been proven by scientific literature that indeed, butyl diglyme has this issue regarding it's storage: Diethylene glycol dibutyl ether

I have a question regarding this: should we store butyl diglyme over sodium hydroxide (as it's done with other ethers) to reduce the peroxide formation?

According to what I have read, a way to test for organic peroxides concentrations in these organic solvents in to make a solution of an iodide salt and glacial acetic acid, take a little bit of the solvent with a pipette and mix it with the testing solution, the darker the color it gives, the bigger is the concentration of peroxides.

What do you think?

Thanks for reading,

- Ismael.

 

[Lino1406]

AuCl4- is a stronger oxidizer then oxygen and no reaction was reported. In addition, the repeated use ensures some humidity is present

 

[isma_123gold]

AuCl4- is a stronger oxidizer then oxygen and no reaction was reported. In addition, the repeated use ensures some humidity is present

Do you have a citation for this? Because I have a hard time believing AuCl₄^- is a stronger oxidizer than molecular oxygen. In the case of diethyl ether, for example, it's not just oxidized by oxygen, but it also combines with it to form the peroxide; in the case of the butyl diglyme, if the tetrachloroaurate anion really is an stronger oxidizer than oxygen how does it not oxidize the diglyme when it's clearly reported in the scientific literature that oxygen can, but even if the anion could oxidize it, it couldn't combine with it as oxygen can: thus not forming the peroxide.

 

[Lou]

I will test some ten year old stuff tomorrow and see if it has any in it.

 

[isma_123gold]

Thanks, Lou. I really appreciate it.

 

[orvi]

And as butyl diglyme is also an ether, it is not a weird assumption that it could form dangerous peroxides upon prolonged exposure. It has been proven by scientific literature that indeed, butyl diglyme has this issue regarding it's storage: Diethylene glycol dibutyl ether

I have a question regarding this: should we store butyl diglyme over sodium hydroxide (as it's done with other ethers) to reduce the peroxide formation?

According to what I have read, a way to test for organic peroxides concentrations in these organic solvents in to make a solution of an iodide salt and glacial acetic acid, take a little bit of the solvent with a pipette and mix it with the testing solution, the darker the color it gives, the bigger is the concentration of peroxides.

What do you think?

Thanks for reading,

- Ismael.

as an organic chemist, i would say that every ether tend to form peroxides (except MTBE, it is designed to not do so ). some are more "stable" than others (but stbility isnt the right word for these substances, meaning that some will detonate without disturbing and some need to be heated or at least disturbed).
dealing with peroxides isnt that straightforward as many think, because storing over bases such NaOH or even sodium dont help much in removing them from solution, and man... they form very quickly few days of oxygen exposure/some light or heat speed up the process, and they are in.
tetrahydrofuran (solvent I use relatively regularly) obtain measurable peroxide level (i just drop solid NaI into the solvent, acid is sometimes not needed at all) in just one day. diethyl ether like few days... deeper the yellow colour is, more peroxides you have in.

the proces is a radical one, when oxygen reacts as an radical with carbon of an ether to form peroxide bond. and obviously, it needs oxygen to proceed, and some sort of initiation eg heat or light to act oxygen as an radical. I would recommend storing the ethers in brown glass bottles at least, keep it from light and keep it cool, not hot
in terms of safety, peroxides start to be a serious problem, when they are concentrated down (eg by evaporation, because they have much much higher boiling points than former ethers). i certainly DON´T WANT TO UNDERESTIMATE THE DANGER, but i have never experienced the explosion or decomposition of peroxides while distilling solvents like THF or diethylether/dioxane on daily basis. but i take precautions and dont use old solvents without testing peroxide level and destroying it properly, and never evaporating to dryness, leaving liquid residue, which is diluted with water and disposed.

you can get rid of the peroxides from solvent by washing it with FeSO4 solution, or by treating the solvent with triphenylphosphine (conveniently used in laboratory). i heard that ascorbic acid also do the trick, but it should be tested firstly to determine if it works with small sample or the solvent.

it is good to know all of the dangers, but i think you will be fine using it for aqueous chemistry without heating

 

[orvi]

Do you have a citation for this? Because I have a hard time believing AuCl₄^- is a stronger oxidizer than molecular oxygen. In the case of diethyl ether, for example, it's not just oxidized by oxygen, but it also combines with it to form the peroxide; in the case of the butyl diglyme, if the tetrachloroaurate anion really is an stronger oxidizer than oxygen how does it not oxidize the diglyme when it's clearly reported in the scientific literature that oxygen can, but even if the anion could oxidize it, it couldn't combine with it as oxygen can: thus not forming the peroxide.

it is much more about reaction mechanism. in terms of potential, AuCl4- is stronger oxidizer than molecular oxygen in typical reactions performed. it make sense because gold does not dissolve or tarnish in the air, even we do AP, that dont dissolve gold either. reverse reaction should have same, but opposite value of potential (eg "oxidizing/reducing power"). but this is idealized. depending on conditions and solvent used, this isnt necessarily true

thing with peroxides formation in ethers is, that it isnt a typical redox reaction, but a radical one. oxygen could under circumstances act as biradical, thus reacting with substrates of "proper energy" in single electron transfer reations
ethers are more or less resistant to typical redox oxidation with basic oxidants, but in terms of radical oxidations/reductions, they fail to withstand the conditions

 

[Lou]

No iodine from my diglyme thanks for reminding me.

Everyone forgets redox is a continuum (pH/temp).

 

[orvi]

No iodine from my diglyme thanks for reminding me.

Everyone forgets redox is a continuum (pH/temp).

and many forgets that redox in textbooks is for ideal setup, not considering other ions in solution, as well as acidity and temperature you mentioned. complexing metal ions with eg chloride anions get things even more interesting

 

[isma_123gold]

Thanks to both of you for answering, the information is very useful indeed!!!