Author Topic: water distillation? (Read 130 times)

akcom · « **on:** May 26, 2011, 03:24:09 AM »

Does anyone else have trouble distilling water on an oil bath? Shit just does not want to condense into the receiving flask. I cant use the gast because there is some sort of nasty vapor in there. I think its time to get my faucet hooked up to an aspirator.

Vesp · « **Reply #1 on:** May 26, 2011, 03:34:24 AM »

Why not just buy distilled water?

akcom · « **Reply #2 on:** May 26, 2011, 03:57:48 AM »

I'm trying to remove it from a reaction mixture

Shake · « **Reply #3 on:** May 26, 2011, 04:26:19 AM »

yeah it is a shit fight, you might have to run ice water through the condesner. you wouldnt think it would be so hard but it really does suck. maybe an aspirator will strip the water off straight down the sink? only if your RXN mixture is high boiling though

letters · « **Reply #4 on:** May 26, 2011, 08:49:41 AM »

water vapors/liquid carry a lot of heat in them and require efficient cooling for anything close to complete condensation. also this could be said as - water's heat capacity (the required amount of heat to change a materials temperature) is high. this has 2 consequences -> as above, the vapors require a large surface area and low temperatures to codnense properly. but also this means that you must give the water alot of heat to change its phase from liquid to gas. this tends to make people agitated and crank up the heat, which then contributes to more heat being delivered to the entire liquid mass, thus generating more vapors at the same temperatures, requiring more and more surface are to cool down.
a simple solution is to use an efficient condenser with a large surface area. Dimroth condensers are only ok. friedrichs are good. double spiral (or more) jacketed condensers work very well. triple spiral is the best, especially is jacketed. also make sure you have a wide condenser so you dont flood it.
vacuum helps, but not by much, since while the overall boiling point is lowered, heat capacity doesnt change by so much.

lugh · « **Reply #5 on:** May 26, 2011, 11:05:20 AM »

Oil baths require a long time to heat up, so if one wants a distillation of water to proceed quickly then more calories are required

The easiest way to provide more calories is with a flame, but of course that causes glassware to crack more easily

Wire gauze is used to spread the flame out so breakage is less likely, but heating with a flame does cause breakage eventually no matter how many precautions are employed

Metal labware is very useful for such efforts

Sedit · « **Reply #6 on:** May 26, 2011, 01:41:34 PM »

Have you tried boiling chips? It sounds like there is something keeping the water from boiling correctly perhaps a dissolved oil or a heavy alcohol or possibly some salt altering is BP.

More information about the reaction contents would make this much simpler. Feel free to PM me and I will see what I can come up with.

Shake · « **Reply #7 on:** May 26, 2011, 01:48:46 PM »

sedit have you distilled water? its a joke it fully doesnt work.. maybe my condenser is too short, but i was surprised when i tried, just got a big steam filled apparatus.. wierd

Sedit · « **Reply #8 on:** May 26, 2011, 01:50:12 PM »

What?

Shake · « **Reply #9 on:** May 26, 2011, 01:59:33 PM »

Quote

It sounds like there is something keeping the water from boiling correctly

stirbar and all, boiling chips, doesnt change anything, distilling water is a different ballgame.. my money is on letters post

akcom · « **Reply #10 on:** May 26, 2011, 02:10:41 PM »

Shake: Agreed, I've had several people tell me the same thing. just came here to see if anyone had any bright ideas.
Letters: Thats some great information, but I can't wait a week to finish this reaction while my new condenser comes in the mail

I'll just have to try with the aspirator and see what I can do. If the water just gets taken down the drain thats A-OK with me.

edit: I've used ice water and it helps but its not amazing.

letters · « **Reply #11 on:** May 26, 2011, 06:14:06 PM »

yea, if you can let the water go down the drain, that might work for you. i dont like sending stuff down the drain due to environmental concerns.
next time, get a big ass condenser for water evaporations. also give it lots heating. cold cooling water is mandatory for condensing water vapor, especially when not having large cooling surface area.
Another idea you might fancy to try is to use 2 condensers stacked on top of each other, if you have an extra one.

Sedit · « **Reply #12 on:** May 26, 2011, 07:07:21 PM »

I have never had the slightest issue distilling H2O. Naptha on the other hand is a bitch to me.

salat · « **Reply #13 on:** May 26, 2011, 08:36:21 PM »

Do you have Zubricks Organic Chemistry Survival manual? If not it's posted on a sticky over at wetdreams -its a must for this kind of stuff.

If you've seen pics of my setup you'll also notice insulation on everything. If you're not using water in the condenser that is definitely a problem - air cooled might work for a reflux if you're not getting things too hot but distillation requires cold water.

My setup has a big cooler with holes in it for the tubes. Inside is a pond pump and water, I dump a bag of ice in there and go all day with it.

You should also consider insulating your flask that you're heating - it makes a big difference in how fast things get going. My husband nagged the heck out of me about it til I tried it but it made such a big difference I rarely do without it now. I make my own wraps out of aramid (from a AF flight jacket) or fiberglass cloth and insulation or batting inside. Felt works ok if it doesn't get too hot - or ironing board cover works too.

Salat

akcom · « **Reply #14 on:** May 26, 2011, 09:18:55 PM »

Yeah I definitely insulate and use ice water. I just got my aspirator hooked up and its working well enough although when I have the water at full blast it makes my pipes leak :-x

Shake · « **Reply #15 on:** May 26, 2011, 09:28:58 PM »

this was my first setup but i found a pond pump doesnt like to pump ice water.. like the properties of ice water run like syrup through the pump..

You should listen to Xbee more salat, if you dont insulate the hotside with at least alfoil you will be there all day long distilling oils, i learned that one the hard way

I wouldnt even distill naptha id just evap it, but thats only becase it is abandunt.

although last time i did that was in the oven, i closed the door for a second to build a little heat.. i intended to evap in a warm open oven with airflow from a hairdryer. i closed the door for a min, it wasnt even hot but warm, then i opened it a crack and used the hairdryer

you ever see a flame thrower? how the front has a little ignition flame? that was the hairdryer.. The oven detonated BOOM and everything caught fire, i burned myself all over, lol..... naptha

i have never been so shocked in my life, it was like a potato cannon the size of an oven, i was lucky the door was closed the flames went above my head and burnt all my hair. the door blew open and threw me back into the cupboard behind me.

it boils at 50-60, i guess i should have thought about how much fumes would be generated even at warm tempretures

Theres one for lab accidents

salat · « **Reply #16 on:** May 28, 2011, 12:13:00 AM »

I do listen to him eventually - but it seemed like such a pain in the arse and I like watching stuff.

I do it now to the point you can't see what glassware is in there sometime.

Just won an auction for spherical glas-col heater (think it's like 250 ml), Ive got a 1 and 2 liter but the small one will be nice and the zip close looks cool.

Salat

akcom · « **Reply #17 on:** May 28, 2011, 04:58:22 PM »

Those heating mantles are a life saver. Once I get a 500ml I'll never need an oil bath again

Shake · « **Reply #18 on:** May 28, 2011, 07:39:02 PM »

what about salt? did you try it? man u dont listen

akcom · « **Reply #19 on:** May 28, 2011, 10:15:25 PM »

The salt bath? Yeah, it works but the reaction smells up the place. This one barely smells at all and its gone in a day.

Author Topic: water distillation? (Read 130 times)

akcom

water distillation?

Vesp

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akcom

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Shake

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letters

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lugh

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