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Author: Subject: What are your desiccants?
woelen
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[*] posted on 12-5-2013 at 02:59


I found the anhydrous copper nitrate from this seller.

http://www.ebay.nl/itm/Copper-II-nitrate-anhydrous-reagent-9...

The picture he shows with the petri dish is exactly like the material I have. Mine, however, is sold to me as the tri-hydrate and this color indeed fits the tri-hydrate very well.

The seller may tell that it is anhydrous, but I do not believe that, unless you can really show that it is anhydrous. Heat some of the material in a test tube and see if droplets of nitric acid and/or water are formed.




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APO
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[*] posted on 12-5-2013 at 13:24


Would setting it in open air and tracking how much mass it gains provide usable data?



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woelen
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[*] posted on 14-5-2013 at 03:23


No, that does not tell you anything. It will attract much more water than is present in the tri-hydrate or six-hydrate. It will continue attracting water until it dissolves in it.

[Edited on 14-5-13 by woelen]




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[*] posted on 14-5-2013 at 06:05


In order of frequency, I use KOH, CaCl2, and NaOH. I like KOH because of its strength as a dessicator, and I have more of that than NaOH at the moment. Anhydrous CaCl2 (or possibly the monohydrate) is found in nearly every store around here as Damp Rid moisture absorber, since I am in a humid area. It's not quite as good as the hydroxides, but I have a near limitless supply!
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[*] posted on 14-5-2013 at 06:18


KOH
H2SO4
CuSO4 (I like the color change from anhydrous to pentahydrate)
DampRid
MgSO4
These are what I use frequently, some other more special ones are used rarely.




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[*] posted on 14-5-2013 at 07:24


I have some MgClO4, MgSO4, H2SO4, Anhydrous CuSO4.
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[*] posted on 15-5-2013 at 07:06


I usually use NaOH as a desiccant. It's very hygroscopic and cheap!
The most hygroscopic compound I've ever seen is vanadyl sulfate.
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[*] posted on 2-6-2013 at 10:31


Quote: Originally posted by APO  
According to this "Anhydrous copper nitrate forms deep blue-green crystals and sublimes in a vacuum at 150-200 °C." it fits color specifications. Any way to test if it's truley anhydrous? I got it from eBay seller argon242.


use something that reacts with water?
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[*] posted on 4-6-2013 at 04:21


Well, I have lithium, but that may oxidize just from contact with the Copper Nitrate.



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[*] posted on 25-5-2016 at 03:02


I have used;
Na
P2O5
H2SO4
NaOH
CaCl2
MgSO4
Vacuum
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[*] posted on 25-5-2016 at 03:35


MgSO4 in organic chemistry is just bliss.




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[*] posted on 25-5-2016 at 06:11


Quote: Originally posted by SnehaPatel  
The advent of molecular sieves into the purification and desiccation industry has helped to improve the processes while reducing costs. Molecular sieve 5a, with a pore size of 5 Angstroms, presents a special advantage with its alkali amino silicate structure. Its drying and purification uses stretch from industrial natural gases to industrial liquids. visit for more info http://molecularsievedesiccants.com/


Since you represent a mol sieve supplier, and took the time to post here about your business, do you care to quote terms for a bulk buy for members here? The issue of obtaining reasonably priced mol sieves comes up regularly.
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[*] posted on 25-5-2016 at 10:19


I've only used NaOH so far, but I do plan to try to use CuSO4 and MgSO4.

Question:
Can cobalt(II) chloride be used as a desiccant or would it not work or be ineffective? The reason I'm asking is because I don't have a lot of use for cobalt chloride and I want to try to explore more of its uses.
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[*] posted on 25-5-2016 at 12:48


Ice.

it's not great- but it's easy to get and it's cheap.
Blowing air over ice then warming it up to room temperature will cause the humidity to drop to about 25% which is fairly dry.
If you need drier air that that, you can still usefully start with ice to strip out the bulk of the water.
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[*] posted on 25-5-2016 at 13:40


I use annahydrous CaCl2 or NaOH.
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[*] posted on 25-5-2016 at 13:42


I use annahydrous CaCl2 or NaOH.
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[*] posted on 25-5-2016 at 16:49


I have a lot of dessicants... the one I use most is calcium chloride.



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[*] posted on 25-5-2016 at 17:18


NaOH, H2SO4, CaCl2, Silica gel (Blue indicating), MgSO4 (Anhydrous), Vacuum pump (Mechanical desiccator)

Working on building a vacuum freeze drying system one of these days it'll be finished!
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[*] posted on 30-5-2016 at 04:15


Not a desiccant per se, but I have a small vial with tetraethylammonium tetrachlorocuprate(II) and it is very deliquescent. So much that just by standing inside a fairly air-tight screw vial, it has started to get slightly more crumbled together, as if it was slightly moist sand.

Btw, 200th post in Chemistry in General.




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[*] posted on 13-6-2016 at 03:08
Wow


It's been sometime since I have felt some input of mine may be helpful.

Firstly
For dessicator boxes, of whatever form, simplest is CaCl2, simplest and best is CaO, best overall is p2o5
For solvents mol sieves are completely OTC.
Go to a refrigeration mechanics trade store, in Australia something like a HeatCraft. Go to the drier cores section.
Find the brand on sale that week/month/whatever.
Find the drier core that only does drying(as opposed to drying + acid adsorption etc)
Buy it
At home smash it to pieces with a hammer
Place chunks of it into your acetone/ethanol/etc solvent bottles
An eon ago Rhodium mentioned this technique, it is very sound, refrigeration mol sieves are 3A, small enough pores to not adsorb acetone.
Solid NaOH, great for amines and all carbons (ref Vogel 1956)

Wow I posted again!!




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[*] posted on 13-6-2016 at 04:55


Great to see you, Panache.
Your last four posts were nine months apart. Don't leave it so long. :)




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