Nate_Jack
Harmless
Posts: 2
Registered: 20-4-2024
Location: Netherlands
Member Is Offline
|
|
Alternative for Potassium Permangate in dark to clear reaction
Hello
This is my first post here and I hope it's in the right place.
I am an artists and I want to do a project that includes liquids turning from dark to clear. Preferably from as dark/black as possible to perfectly
clear.
I found that potassium permangate mixed with hydrogen peroxide gives a satysfying result, but the problem is that potassium permangate is not easy to
acquire without a licence in The Netherlands as it is considered a precursor.
My question is what are some non-precursor alternatives I could use for that kind of a reaction?
|
|
|
Keras
International Hazard
Posts: 1013
Registered: 20-8-2018
Location: (48, 2)
Member Is Offline
|
|
For clear to dark you could use a mix starch + potassium iodide solution and add a few drops of bleach. It would turn dark blue immediately.
I’m certain you can do dark → clear using bleach and something appropriate. Did you try squid ink?
|
|
|
Precipitates
Hazard to Others
Posts: 152
Registered: 4-12-2023
Location: SE Asia
Member Is Offline
Mood: Acid hungry
|
|
Sodium thiosulfate, or apparently even reducing agents such as ascorbic acid (Vitamin C), can reverse the iodine clock.
|
|
|
RU_KLO
Hazard to Others
Posts: 245
Registered: 12-10-2022
Location: Argentina
Member Is Offline
|
|
any indicator that is transition from clear to a color.
Phenolftalein (easy to get) but not dark (but violet) maybe a lot of it....
then a proper Ph solution or buffer.
https://en.wikipedia.org/wiki/PH_indicator
(from this list: methylene blue; Cresolphthalein; Thymolphthalein, but I think these are quite rare.. to get.
Go SAFE, because stupidity and bad Luck exist.
|
|
|
woelen
Super Administrator
Posts: 8080
Registered: 20-8-2005
Location: Netherlands
Member Is Offline
Mood: interested
|
|
In the Netherlands, you can buy it here: https://www.laboratoriumdiscounter.nl/nl/kaliumpermanganaat-...
You have to fill in a declaration of use, but that is no problem.
Another place where you can get it: https://www.kamerfilter.nl/search/?search=permanganaat
A small amount of KMnO4 goes a long way. its color is really intense. A few 100's of milligrams are enough to make a liter of water nearly black. If
you then add a few tens of ml of acidified solution of sodium sulfite or hydrogen peroxide, then the liquid immediately loses its color and becomes
colorless. Sulfite is best, hydrogen peroxide also works fine, but it produces bubbles of oxygen as well. In both cases, you need enough acid,
otherwise the liquid does not become colorless, but it becomes turbid yellow/brown, due to formation of a precipitate of insoluble hydrous MnO2 and/or
Mn2O3, depending on exact amount of reductor and pH.
[Edited on 11-3-25 by woelen]
|
|
|
Nate_Jack
Harmless
Posts: 2
Registered: 20-4-2024
Location: Netherlands
Member Is Offline
|
|
Thank you for the replies! Thank you for the tip with the webshops. I thought it would be more difficult i.e. registering as a laboratory at the
chamber of commerce.
I think I will go with the permanganate with acidified sodium sulfite. Does the acid I use matter? Should I go for sulphuric acid or does something
like vinegar suffice for this reaction? What proportions would you suggest for this?
[Edited on 2025-3-11 by Nate_Jack]
[Edited on 2025-3-11 by Nate_Jack]
|
|
|
woelen
Super Administrator
Posts: 8080
Registered: 20-8-2005
Location: Netherlands
Member Is Offline
Mood: interested
|
|
You need a strong acid. You could try hydrochloric acid, which you can buy at 10% concentration in a hardware store (e.g. Gamma, Karwei).
Another option is: https://www.werkenmetmerken.nl/nl/zwavelzuur_15_/p/114370
Suppose that you take 0.3 grams of KMnO4 in a liter of water.
Then take 1 gram of Na2SO3 (anhydrous salt) and dissolve this in 75 ml of water. Add 25 ml of 15% H2SO4 to this and mix well. This solution then can
be added to your 1 liter solution of KMnO4.
If you use 10% HCl, take 60 ml of water and 40 ml of the acid instead of 75/25.
Mentioned amounts are not critical at all, rough measurements are good enough.
|
|
|
clearly_not_atara
International Hazard
Posts: 2825
Registered: 3-11-2013
Member Is Offline
Mood: Big
|
|
Titanium (III) chloride gives a violet solution which is fully decolorized by a suitable oxidizer. It will also slowly be decomposed by air.
|
|
|
MrDoctor
Hazard to Self
Posts: 59
Registered: 5-7-2022
Member Is Offline
|
|
im pretty sure you can produce KMnO4 by electrolysis too, ive seen a video where it was done somewhere, i recall they got all excited because the
solution totally blacked out, but, there isnt really a strong distinction between say, 100mg/L and 20g/L, or something like that. Their yield was too
small to extract or measure it just left a residue staining the glass.
Also, recently i had a run in with some fake iodide, it turned out to be 50% chloride, so i eventually just started adding drops of random whatever
might help, and the iodide solution did go through some very full color changes, which didnt help me at the time since i thought i must have just
oxidized it weird or something. in the end there was maybe less than a gram in there but it was capable of going from an increasingly yellow clear
(due to chlorine buildup) to, a deep red. and for a little while when the iodine crashes out it goes totally black.
Theres a fine line you could balance that on, ideally not using halogen based acids though.
Lastly, while it might not be super useful, you can make something that works kind of like permanganate.
manganese ammonium alum, which is a double salt of manganese sulfate and ammonium sulfate in sulfuric acid, its preparation is as simple as dissolving
equimolar amounts of the respective salts in dilute sulfuric acid and then electrolyzing. the result as you can see in the video attached is at the
anode a very deep purple-red, its not quite as neon pink as permanganate, but its still close, manganese makes some pretty salts sometimes.
supposedly you can also make something similar too using potassium sulfate instead of ammonium.
this double salt will oxidize alcohols or methyl/ethyl/alcohol groups when heated to around 60-90C and can be regenerated infinitely by electrolysis.
apparently you can also destroy/reduce the salt by drying it out, without water it decomposes. I would think that a sulfite salt should be able to
reduce it.
the colorful charged salt is called manganous ammonium alum, while in its colorless double salt form its just manganese amonium sulfate. the molecule
is huge so, im sure theres numerous names it could go by.
The patent its from describes producing it in a saturated slush but, it will form in dilute solutions too. when it is so dilute however that none of
the salt can precipitate/exist as a solid, it will oxidize alcohols to the corresponding acid rather than aldehyde, so keep that in mind, between the
aldehyde and acid form, most things i can guess that will become volatile enough to remove, give a toxic form either way, such as with ethanol or
methanol.
Ammonium bisulfite would probably be a good way to neutralize it if you can get it.
One thing i havent tested is wether or not you can instantly form it using peroxide or not, though i think permanganate and, possibly persulfate, can
auto oxidize it.
Attachment: VID_20220929_195704184.mp4 (3.8MB)
This file has been downloaded 23 times
[Edited on 12-3-2025 by MrDoctor]
[Edited on 12-3-2025 by MrDoctor]
|
|
|
Sulaiman
International Hazard
Posts: 3779
Registered: 8-2-2015
Member Is Offline
|
|
as mentioned by others, methylene blue, used in classic blue bottle demonstration
Not restricted access, not too expensive, very low risks
an intense blue, can be diluted of course.
Blue when oxidised (eg hydrogen peroxide)
colourless when reduced (glucose, vit.C etc.)
also affected by pH : <5 (very dilute vinegar)=clear, >9 (baking soda)=blue
simple waste management.
I expect that you can convert blue to any other colour including black, once digitised.
So called "indicators" are obviously chosen for their colour changes under differing conditions - quickly.
"Bleaching" is usually a slower reaction.
Methyl violet is a commonly available intense dye, that can be oxidised to clear, but it is a one way trip (from memory only)
squid ink sounds good, I guess that most inks and dyes can be bleached.
Food dyes may be of interest?
PS hydrogen peroxide works well as a bleach in an acidic environment
household bleach is alkaline/basic
Household/hypochlorite bleaches when combined with acid can release truly TOXIC quantities of chlorine gas.
So hydrogen peroxide is a good choice for your oxidant.
Higher concentrations of peroxide (eg 50%) will give more rapid/dramatic results,
but one drop in an eye or a few drops on skin will not be fun.
It is chemistry, so protect yourself. (aka: don't suffer for your art)
[Edited on 12-3-2025 by Sulaiman]
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
