How to make a Desiccator Bag for Drying Chemicals
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- Опубликовано: 10 сен 2024
- In this video we make a desiccator bag for thoroughly drying hygroscopic chemicals. Some chemicals are hygroscopic, meaning they absorb water from the air and become moist, mushy, or even liquefy. For highly accurate work and good results in experiments the chemicals should be dried before use. A laboratory device for doing this is called a desiccator.
Laboratory desiccators use vacuum and drying agents. A simple home desiccator can be made from an airtight resealable plastic bag and a hygroscopic drying agent like sodium hydroxide.
Simply get a plastic container and fill it up with sodium hydroxide, then place it inside the bag along with a container of the chemical you intend to dry. Seal it up and wait.
Thorough drying can take weeks. Sometimes you might run into the problem where the top dries before the bottom, you'll have to grind your chemical every so often to continue drying.
The bag is also good for storing already dry chemicals to keep them dry. After using a chemical, return the unused portion to the bag to dry out the tiny bit of humidity it absorbed while you were working it.
Other drying agents you can use are:
Potassium hydroxide
calcium chloride
silica gel
sodium sulfate
magnesium sulfate
calcium sulfate
molecular sieves
sulfuric acid
I don't use glass because the agents might dissolve glass. Plastic container are cheap and disposable.
This desiccator only works on solids, it does not work on liquids and cannot be used for concentrating acids, peroxide or drying alcohols.
NurdRage you are a natural teacher! In the past few months I have learned stoichiometry, moles and how to use the periodic table. I have learned how to synthesize a whole bunch of compounds and extrapolated that to make others relevant to my hobby (electro-metallurgy) I seriously owe you a debt of gratitude. Thank you for sharing your knowledge.
Robert Ritchie TNQW
I couldn't agree more! Hes awesome at explaining complex topics and making chemistry interesting.
I used to live in my car! Containers of calcium chloride were very helpful for removing humidity from my breath!
@silverblotter
Why the sudden flaming? did youtube make an error again and pop this video into everyone's subscriptions boxes making it look like i reuploaded it?
@skarrip
Oh the bag is very slow. much slower than other methods. But what makes it useful is that it's extremely thorough, and can dry things that can't be dried by other methods, like temperature sensitive chemicals that would be destroyed if you tried to heat them.
We facing this problem for hygroscopic chemicals … I will definitely try to implement your method 👍
Awesome.
@zcuttlefish
good suggestion!
It cannot be used to absorb acidic gases like NO2,SO2 and CO2. But otherwise, go for it.
Just a tip, if wanting to save on chemicals; you could take the dissector in this case, silica beads or sodium hydroxide and heat them up removing the moisture from them as well. Then they are good as new and are ready to be reused.
Fyi - Not all desiccants are the same so always read upon the hazards of heating what ever desiccant you are using.
Whoa. Didn't realize that was possible (at least not by current technology.) If you could think of an experiment that uses that technique, I'd love to see it, if only to see the metal sublimate:D
Thanks janeeee999! I got some and it has some type of indicator mixed with the silica gel which turns red from blue when you need to dry it out again. ("Flower Drying" cost about 10USD for 1lb 8oz ) Thanks for posting that and of course thanks nurdrage.
I used this technique to dry my "sealed" cell phone battery after getting my phone wet. Got all the circuits completely dry but the phone still wasn't working. Turns out it was the battery. The desiccant was calcium chloride bought in the paint section of the hardware store.
You made this on my Birthday!
Very good. Can dessicants be heated and reused?
@weldmaster80
The sodium hydroxide will eat through the glass if given enough time, the point of using plastic containers is that they are disposable.
If you want to reuse your desiccant i instead recommend going with the silica gel or one of the sulfates mentioned in the video description.
@skittlesmonkey thanks. tried it and it helps a lot. you can boil the water out after its too wet.
@pinkytm1
I think your better bet might be to mix milk of mangesia, (which is magnesium hydroxide) with hydrochloric acid. You'll get a purer product that's easier to crystallize.
But if what you have is all that's available, then i would first try a slower method of cooling. sounds like its cool too fast and causing it to crap out like that.
Go with a commercial dehumdifier system. People themselves constantly breath/perspire moisture into the air so trying to get 100% dry air is ultimately impractical.
@Incredibleman007
kinda, ammonium nitrate is not as hygroscopic as NaOH though, so it might not dry all things as thoroughly as you want it to.
But i suppose it can't hurt to try.
@dragonridley
As long as the target chemical does not itself evaporate, then it doesn't matter. Only vapors, like water and acid will get absorbed by NaOH
@rzezagar I don't see why not. It's just the transfer of moisture from one substance to another. It's like placing ice in water with something to transfer the cold from the ice to the object, except you're moving moisture through air instead.
Magic.
thanks thats helpful
One problem I can see is that PET drink bottles will hydrolyze with conc. NaOH (or other strong bases). As the dry NaOH absorbs water and forms an aqueous solution, you might get to the point where the bottle is so weak it can fall apart when you move it.
I use drying agents that can be regenerated by heat such as MgSO4 or CaSO4 that won't be so aggressive to bottles such as NaOH/KOH.
Ok thanks :) Already was afraid that it wouldn't work.
Just a question ,thought from a non chemist, can these materials be used to absorb water from atmosphere and then be separated from the h2o to obtain the water ? Im thinking a passive moisture collector for drinking purposes concept...
Can this be use for bio-briquette ash? For drying and testing it?
this is inefficient and there are things that do this non chemically, dehumidifiers but you arent meant to drink the water from the, because it has bacteria. this concept itself is never going to be efficient enough to use in like countries with water scarcity (ie africa) and it'll need electricity anyways (both electric dehumidifiers or chemical desiccants, dehumidifier machines need electricity to run a refrigeration system to condense water from air and chemical desiccants need to be heated to release the water
bag might be made of an ester-based polymer which is susceptible to hydroxide. i reccomend putting the sodium hydroxide in a tin can or finding a bag from a different brand. Not all bags are susceptible to hydroxide.
Could you pull the water out of alcohol or would the alcohol evaporate too?
@1ukjunglednbraver
The desiccator bag only works on solids. Liquids require a different approach.
I'm putting together a video on that, but it won't be ready for some time.
@Crayon Eater
I suppose if you have that much silica gel then go for it :)
Good thing about silica is that you can bake them dry and reuse them.
@joewilder
you could try, but since this takes a week or so to dry stuff i think your food would go bad long before it was dry.
Yes, just heat up epsom salt (MgSO4 7H20) on an aluminum sheet in the oven at 375F for 2 hours. Just don't layer the epsom too thick.
@Libertarianist
hehe, I got a vac pump at lab powerful enough to sublimate metal. I might show it sometime.
Small note to anyone replicating this method: most ziplock bags are poor quality and leaky, much less air-tight. Ive made a few messes before assuming they would be. The problem is always in sloppy cutting at the edges of the opening mechanism (which can vary from bag to bag) - so check that, test the bag, or at least double bag if it's important that the seal is good.
Can this method be used to dry I2 crystals, or will it not work because I2 sublimates might react with the bag and/or desiccant?
I never knew sodium hydroxide was a good desicant. Is it more effective than calsium chloride? Because that's real cheap to buy in bulk (intended for ice melting driveways). Probably not nearly pure enough for direct experiments, but as a non-contact dessicant it probably shouldn't matter?
Pretty Useful.
Yeah, it will. It'll be faster even than one big container, because you'll have more surface area of NaOH exposed to the atmosphere of the bag.
I was hoping to use anhydrous calcium chloride to dry seeds before freezing for long term storage. Do you think it will be hygroscopic enough?
@iRichiepoo
That's how the one in my lab works. But i tried to keep this one simple so even a kid could build it :)
But if you got a vacuum system, go for it ;)
That is great. Would this work with damp oxalic acid dihydrate powder and Silica gel as the drying agent? I have a tub of oxalic acid dihydrate that seems damp.
no, its just your vids are nice and i look forward to new vids every day please make more vids... lost more
How to mske Non- Linear optical material of L-Arginine Perchlorate ? Plz Reply❤️ it's very hard to dry... Can I dry Glycine Perchlorate same way? it's Hygroscopic Material, very Hard to Dry, Please Help me Friend ❤️
Ethylene glycol can be used as dessicant too!
@antiswattt2
Sorry, it won't work on liquids because it will absorb the liquids themselves too. :)
@pea1222
why do you want dysprosium nitrate?
Yes! but only if its anhydrous, to make it anhydrous heat it up to a high temperature in a combustion stove/fire or with a propane torch. It should be a white powder, epsom salts comes in pretty transparent crystals and is the heptahydrate(already has 7 H2O molecules stuck to it making it a useless drying agent)
thanks! this is useful!
it actually isn't....
that's just a pen name. or some thing of the sorts
Butyl Lithium : his name : is an organic compound of Lithium.
with P, S, and T butyl lithium, they are as flammable as flammable can be
igniting at room temperature and reacting with the oxygen immediately to form a flame
@Pipewing
sodium hydroxide cannot be reused.
Silica gel and molecular sieves (not shown) can be reused, but are hard to get.
Common sieves like #3-4 can buy cheaply, Bought in bulk of eBay not cleanest little dusty, reuse from work or lab. Probably lost more than have. Can reuse NaOH if just H20 in example heat it dry? Like other agents, not fast & hot unless want a block-solution to large solid. Increase incrementally in temperature over 2-3 steps. What was time lapse? Big fan, new generation!
PLEASE HELP! I usually leave out such compounds to dry out such as copper 2 chloride, and other such products, however ! Recently, I've finally invested in a gem of a vacuum chamber, and I want to , (for example!) Place the forever seeming to fully dry out slurry of cu 2 chloride. Now is it ok, while I place the container of seemingly stubborn cucl2 in the chamber, as a desiccant, I took a small Pyrex bowl, and filled it half way with Na-Oh placed a paper filter over it, and then placed the bowls plastic snap on lid, which I had drilled 9 small holes on the top. In your opinions, once I place both containers into the chamber and bring the atmosphere to 29.92 hg, for 7 and a half hours, do you think the Na-Oh will be effective? And I don't have any other desiccant types , at this moment. I appreciate any feedback.
@luisfranciscanora
Check out my video on how to dissolve glass.
The exact same process still happens at room temperature just much slower. If left in there for weeks, sodium hydroxide can still do extensive damage to my expensive labware.
Can I use Arm & Hammer moisture powder to agsorb the water? It seems so benevolent compared to Na OH
@Zapo147
Sorry this only works on solids, not liquids.
@aonomus
I think you missed decomposition of the bottle in the video.
btw, can you use a vaccume (not one for floors, i mean a lack of gas) to boil the water? or will it not remove all the water.
@Ztuibyman yes and it is even better, this probably just for people who do not have a decent vacuum pump.
can i use this method to determining relative humidity that surrounding a piece of food in dry container by combining a hygrometer to the bag?
nurdrage this may be a silly thing to ask but can u use a Desiccator to remove water from a ethanol alchol water mix in a bag..or do u no any other way to make ethanol pure like dry ethanol..sorry i was never so great at english
Very straightforward and useful. Thanks. Are there any drying agents that can be recycled by drying in a more conventional manner?
Would there be benefit in bringing the temperature up (e.g. a hot window sill or radiator) if you can determine the decomposition properties of the chemical in question? Also, however much desiccating you do, it doesn't affect the water of crystallisation of the product, e.g. hydration, decahydrate etc)?
i got a a 5 (in your school its maybe an A... well i just mean a highest mark u can get ;P) in shcool 4 thinking this out "myself". Thanks nurd rage
Ive made this bag and my bag begins to decompose, just like the way your soft drink decomposes. I am using sodium hydroxide I have also used silica gels and the same effect occurs what have I done wrong?
Ok so if sodium hydroxide absorbs moisture how do i make the sodium hydroxide or obtain it ? I want to see if it will suck moisture out of my 3d printer plastics ..
could the NaOH be reused, maybe use glass ciontainers and heat in oven on a low temp (maybe 200 F) than re use... asuming yor not deaing with something that makse much acidic gasses.... than once you dont need it any more I can still use it to make soap. OH, you should do a vid on soaponafication (sp?)
once again you rock!
You said the NaOH would absorb acidic vapors. would that be a problem if the target chemical is acidic?
there is a better drying agent out there - magnesium sulfate can be bought in big bags at the pharmacy as epsom salt. It won't eat through your container, and is reusable. You just need a hot plate to remove the moisture from the mgso4. I might post a vid on this later.
I've subscribed, I've rated! And now heres my comment
@NurdRage the sodium hydroxide cannot be regenerated, i thought about copper sulphate as desiccating agent because theoretically the blue copper sulphate pentahydrate can be dried in a oven until it is white anhydrous copper sulphate.
would it be a good idea to use the sulphate alongside the sodium hydroxide, of course in separate containers?
Could I use something that isn't a compound for a dessicant, something like flour or rice?
I personally don't use a plastic container such as a drink bottle as most are made from PETE/PETG, a resin which is very vulnerable to NaOH (as shown in the video). For my desiccator box (I use a small Tupperware box because I'd rather have something that is easier to move than a bag should it need relocating) I choose to use disposable clear Polystyrene shot glasses (can be purchased very cheaply), they are resistant to Sodium Hydroxide as well as most other desiccants you can use.
in theory the best thing you can go for is PTFE. PTFE will not be corroded by any acid and base. ( glass will be attacked by NaOH but very slowly) However, PTFE is way more costly.
@skittlesmonkey planning on burning oak. Oak plywood for that matter. Its hard wood, but just cut finley so it would right?. So basically make it evaportate by heating it up. Doesnt it get flammable at high tempatures?
I know magnesium sulfate can be used to dry solutions by removing all the water, but can it also be used for this in place of sodium hydroxide?
very cool! i can use this to dry out my ammonium perchlorate (:
nurdrage i cant buy pure dry ethle alcohol in the uk but i can distill it myself upto about 95%..could i dry it by adding dry magnesium sulfate salts and then remove the crystels after...i have seen this done to dry other solvents like petrolium ether i was just wondering if it would work with ethel alcohol...sorry about my speling i know its poor.
im trying to make rust oxide by connecting an iron rod to a positive terminal and putting it in water with the negative terminal in the water. I am making this for later production of thermite, but its taking FOREVER to dry, and when i tried cooking it, i barely got any rust oxide. I think its hygroscopic, but i dont want to waste time making a desiccator bag i dont need.
Would anhydrous magnesium sulfate work the same?
It does only work with solid substances which are solved in a liquid, it would never concentrating nitric acid cause it asorbs the water and the NO2 from the hno3.
I bought lab grade sodium hydroxide ,but for some reason it is mushy ... what can I do to fix this and make it solid again ?
no some hardcore stuff is high strenth sulfric acid..its stronger than the base stuff
Can this be an alternative to vacuuming mollecular sieves via the (microwave method)
@pyrogirl1985 instead of using a bag, look for a adequately sized jar with a lid that can seal it well. put the sodium hydroxide at the bottom and make a kind of tripod with plastic (cd, cd case, ruler, use whatever comes to hand) to keep your target substance and it's container above the sodium hydroxide.
@johnpaulpullicino
Your profile says you live in malta. I don't know the local laws there or the availability of chemicals.
ok thank u
But, if i were to crystalise a copper sulfide solution would the desiccator speed up the process ?
sorry for my english :P
Would this work any better if it was in a vacuum or a partial vacuum?
Can I do this to purify H2O2, because heating it make it decompose quite a bit...
I'm just wondering why the height of the desiccant container needs to be similar to the height of the container of the item you want to dry, I would think a low, large dish would be best for absorption, isn't the humidity roughly the same if the levels of chemicals in the containers is the same? The only rationale that comes to mind is using similar heights to avoid trying to dry out the air in the bag to conserve desiccant. Thanks!
Can potassium hydroxide be used as a drying agent? Also, what is the balanced equation when potassium hydroxide reacts with water? I understand The Brønsted Lowry Concept of acids and bases but I haven't found an example yet of KOH reacting with water.
i got some sodium nitrate that is with too much humidity and don't work in anything, can i use this method to dry it?
Can this be used for hydrogen peroxide an alcohol?
Hydrogen peroxide is an oxidizer not an alcohol.
sodium hydroxide does not "eat" glass at room temperature. I have had a 1L beaker of solid sodium hydroxide for months in a dessicator and when I change it every few weeks it is perfectly fine. Also the absorption of water from a hygroscopic compound via evaporation does not create enough heat to do anything to plastic.
Can DMT Crystals Dry
But how do you dry the sodium hydroxide?
Do you have any suggestions for using desiccators in a duct system to pump completely dry air into a room/building? I thought about desiccating rods in combination with a membrane that will filter some of the water out, but it seems like the components would need to be replaced too often for that to be viable.
Is it posible to dry tuolene with this process?
No
Magnesium sulphate
This works in very few cases - The H2SO4 will get concentrated upto 70-80% and stops losing water due its affinity- probably best to boil it down....
@pinkytm1
sounds like a good idea, go for it
Just wondering, I have around 40% sulfuric acid. If I use NaOH as my desiccant would it absorb any water? H2SO4 is very hygroscopic I know but would it give up water until it starts to absorb more; what would that point be?
Would this work for concentrating nitric acid, or other non-crystallizing fluids?
How much time it's take to dry