Sciencemadness Discussion Board

Refluxing without a tap?

cmos6667 - 12-4-2015 at 12:13

Hi folks,

I have limited space and probably no tap water but most reactions obviously need reflux...
Is there anybody who's been in this situation and used something like a computer watercooling kit?
What other options are there? Microwave unmodified? It can heat water to way more than its BP at 1atm, does this apply to say ethanol as well?

I appreciate any help

Etaoin Shrdlu - 12-4-2015 at 12:15

I use a small water pump (the type used for tiny fountains or aquarium filters) to cycle water from a bath, through the condenser, and back.

cmos6667 - 12-4-2015 at 12:24

Brilliant idea, thank you! :)
One more thing, what kind of vacuum pump would you recommend? (Like now I know to look for aquarium pumps but I can't think of another field that uses vacuum pumps)

ISCGora - 12-4-2015 at 12:38

I use same setup with small water pump and bucket with water since I really don't like the idea of just wasting tap water over a course of 4h,plus your water bill isn't skyrocketing when you do anything involving condensing.

macckone - 12-4-2015 at 12:58

An aspirator pump can be run using the same type of water setup, with ice water and salt you can get decent vacuum. Air conditioning vacuum pumps will pull really low pressures but generally aren't chemical resistant. That means you need a trap or neutralizer to prevent damage. The good news is that a/c vacuum pumps are usually resistant to ammonia since it is used as a refrigerant. Used refrigerator pumps are also popular among the home science crowd. There is a thread on those.

ISCGora - 12-4-2015 at 13:07

I planned to make refrigerator vacuum pump but I am not sure for how long can it run before it gets overheated and I kind don't have a good way of disposing of freon from the engine.And I know it is highly toxic and it is very bad for atmosphere,plus I think when heat is introduced you get some really toxic stuff that was used in wars as a chemical weapon.

[Edited on 12-4-2015 by ISCGora]

Texium - 12-4-2015 at 13:37

I don't have a pump, so whenever I use a condenser I hook it up to a jug of ice water that I have propped up high and let it gravity feed through the condenser, manually changing out the water every several minutes.
Not very practical, but it works.

aga - 12-4-2015 at 13:52

Quote: Originally posted by cmos6667  
I have limited space and probably no tap water but most reactions obviously need reflux...

Seems that the process for making Sodium Acetate is free from the need for reflux, as is Glacial Acetic acid, anhydrous Ethanol etc.

Similarly Aluminium Sulphate, Tetrachlorocuprate, Gallium Nitrate, Potassium Chromate and Sulphur Chloride, amongst many, can be accomplished without reflux.

Do you have a specific Organic Chemistry requirement ?

HgDinis25 - 12-4-2015 at 14:17

This has probably been mentioned but:
https://hobbychemistry.wordpress.com/2015/03/30/how-to-water...

cmos6667 - 12-4-2015 at 14:18

Quote: Originally posted by macckone  
That means you need a trap or neutralizer to prevent damage.
What are those? Can you use something similar to a drying tube but with different pellets?
Quote: Originally posted by zts16  
I don't have a pump, so whenever I use a condenser I hook it up to a jug of ice water that I have propped up high and let it gravity feed through the condenser, manually changing out the water every several minutes.
Not very practical, but it works.
Not sure that'll work with high BP oil distillation but thanks ;)
Quote: Originally posted by aga  
Quote: Originally posted by cmos6667  
I have limited space and probably no tap water but most reactions obviously need reflux...

Seems that the process for making Sodium Acetate is free from the need for reflux, as is Glacial Acetic acid, anhydrous Ethanol etc.

Similarly Aluminium Sulphate, Tetrachlorocuprate, Gallium Nitrate, Potassium Chromate and Sulphur Chloride, amongst many, can be accomplished without reflux.

Do you have a specific Organic Chemistry requirement ?

Actually yes... there is suprisingly scarce information on organometallic decomposition and I also haven't seen any TM catalyzed halogenation...

One of my ideas involves making Fe-O-R compounds and see if I can get something similar to NO2 radical from decomposition of Fe(NO3)3 and radical trap FeCl3.
Another one involves using Zn to make anhydrides using vacuum + heat (no need to use acyl chloride intermediate -> doesn't need SOCl2 or similar)...

I don't see why any of this wouldn't work, and it shouldn't be too bad if done outside ;)

aga - 12-4-2015 at 14:35

Quote: Originally posted by cmos6667  
Actually yes... there is suprisingly scarce information on organometallic decomposition and I also haven't seen any TM catalyzed halogenation...

I don't see why any of this wouldn't work, and it shouldn't be too bad if done outside ;)

Whenever i hear of Organic and Metallic together, it always reminds me of this :

http://en.wikipedia.org/wiki/Karen_Wetterhahn

zts16's suggestion of a couple of buckets is a perfect Practical solution to your original No Tap question, as a working solution.

I'd suggest less ambitious OC if your lab is lacking even buckets of water.

cmos6667 - 12-4-2015 at 14:57

I meant using water for vacuum (distillation), but the idea of using an aquarium pump with water+ice is great

Also, no, I won't be using mercury (not even for reductions)... I am well aware of toxicity of things, but I doubt that organometallic decomposition (Fe and Zn) will do that much harm

[Edited on 12-4-2015 by cmos6667]

aga - 12-4-2015 at 15:23

OC isn't my thing at all, and what you're talking about is beyond me, so i'll butt out.