WannaBeDrD
Harmless
Posts: 10
Registered: 5-1-2011
Member Is Offline
Mood: No Mood
|
|
Storage of KOH solution
Can a 5-10% solution of KOH safely be stored in a glass jar?
I've spent two days searching both this forum and Google, but to no avail. I probably just haven't hit upon the magic search phrase.
Thanks
|
|
|
ScienceSquirrel
International Hazard
Posts: 1863
Registered: 18-6-2008
Location: Brittany
Member Is Offline
Mood: Dogs are pets but cats are little furry humans with four feet and self determination! 
|
|
That depends on how on how long you want to store it and how pure you want it to be.
Cold potassium hydroxide of that concentration may absorb water from the air so it might gradually become more dilute depending on relative humidity.
It will also absorb carbon dioxide from the air tp form potassium carbonate and bicarbonate if it can.
It will dissolve a little silica from the glass over time but this is not so significant, it might attack the stopper and seal but this is dependent
on what it is made of.
A hard glass bottle with a polypropylene cap could keep this in for decades, a soft glass bottle with a traditional cork will not achieve much!
|
|
|
WannaBeDrD
Harmless
Posts: 10
Registered: 5-1-2011
Member Is Offline
Mood: No Mood
|
|
So what would be the proper storage container? HDPE? PET? Something else?
|
|
|
WannaBeDrD
Harmless
Posts: 10
Registered: 5-1-2011
Member Is Offline
Mood: No Mood
|
|
Finally found something. PET would be bad...Sodium and Potassium Hydroxides are used in the recycling process to hydrolyze PET.
LDPE and HDPE should be OK.
This is a cool listing of chemical resistances for plastics. I'm sure there are others...
http://www.calpaclab.com/pages/chart.html
Thanks for the reply ScienceSquirrel.
|
|
|
mr.crow
National Hazard
Posts: 884
Registered: 9-9-2009
Location: Canada
Member Is Offline
Mood: 0xFF
|
|
Depends on what you use it for. If it is a 1.000N volumetric solution used for titration then it can't be stored for too long. If it is a general
reagent then absorbing a little water and CO2 is ok. If it drops from 10% to 9.9% it doesn't matter.
HDPE should be fine. Like the bottles for rubbing alcohol. I always wrap the cap with electrical tape to seal it up.
Double, double toil and trouble; Fire burn, and caldron bubble
|
|
|
smuv
National Hazard
Posts: 842
Registered: 2-5-2007
Member Is Offline
Mood: Jingoistic
|
|
storage in polyolefins is best.
"Titanium tetrachloride…You sly temptress." --Walter Bishop
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
