Sciencemadness Discussion Board - How to make an oil bath???

How to make an oil bath???

bluamine - 12-12-2015 at 14:29

Hi everyone!!
I want forum experts to explain to me what can I use in an oil bath? (To make my question clear I want to understand it generally, then in making ethylene from ethanol)

subsecret - 12-12-2015 at 15:11

This is something you could very easily google or search the forum for.

There's your answer.

bluamine - 12-12-2015 at 15:58

Quote: Originally posted by subsecret

This is something you could very easily google or search the forum for.

There's your answer.

i dis so before but I found different chemicals could be used so can I choose anyone of them?

chemrox - 13-12-2015 at 15:47

Do you have heater? Mine was deep fat fryer. It is amazingly precise in temperature control. I can heat 10 ml t0 2000 ml rb flasks. I can hold the oil +/- 1*C!!!
I use diethyl pthalate for the "oil." It doesn't smoke below ~ 300 *C but I try to use it in the hood for higher temps. For some reactions I prefer it to heating mantles. I found it at a garage sale. It hadn't been used. Pure serendipity.

JJay - 13-12-2015 at 19:27

It is usually recommended to use mineral oil, which has similar properties to diethyl pthalate. Vegetable oils are generally cheaper and easier to obtain. Under 200 C or so you can use a vegetable oil with a high smoke point. I often see people on here use expensive oils with low smoke points (like peanut, canola, olive, etc.) - but soybean oil is cheap and good to fairly high temperatures. It is sold as "vegetable oil" in the United States. You can use a search engine to find the smoke point of any particular oil.

I usually heat my oil baths with immersion heaters.

Detonationology - 14-12-2015 at 08:36

DOT 3 silicon brake fluid

Mabus - 15-12-2015 at 11:54

Has anyone used molten paraffin wax as an "oil" bath?

[Edited on 15-12-2015 by Mabus]

Praxichys - 15-12-2015 at 12:46

Quote: Originally posted by Mabus

Has anyone used molten paraffin wax as an "oil" bath?

I used to. It's nice because you can just let it solidify and the flasks break right off the chunk. It's also easy to store the bath without having to drain it to prevent spillage/contamination.

The problem is that if you take the flask out before the wax is solid (as usually happens when you stop a distillation, etc), the solid wax is a pain in the ass to scrape off the flask. Heat guns and paper towels help, which make great fire-starters afterward, but in the end it's a tedious mess. It is also inevitable that the lab bench/jacks/clamps need wax scraped off.

Also, my bath is an electric saucepan, so I use it with both water and oil. The wax would have to be melted and poured to convert it back and forth from water to oil anyway, so I just use DOT 5 silicone oil brake fluid. This has the advantage of not oxidizing with air, it boils low enough to be distilled if it gets contaminated, it's non-flammable, and cleans up with soap and water. It will also help keep apparatus rust-free if you wipe down your clamps and stuff with the oily rag after cleanup.

But really I stopped using oil baths in general as soon as I got a heating mantle.

[Edited on 15-12-2015 by Praxichys]

aga - 15-12-2015 at 12:54

Quote: Originally posted by Praxichys

It will also help keep apparatus rust-free if you wipe down your clamps and stuff with the oily rag after cleanup.

That is an excellent suggestion.

Quite a lot of Shedworld steel items are seriously rusty these days.

Maybe filling the shed with Chlorine and then HCl gas was not such a great idea.

arkoma - 16-12-2015 at 04:54

Fry-Daddy. 18 bucks at Wal-Mart.

Detonationology - 16-12-2015 at 05:03

Quote: Originally posted by arkoma

Fry-Daddy. 18 bucks at Wal-Mart.

Is this it? Is the temperature variable, or would that require the addition of a rheostat?

Screen Shot 2015-12-16 at 7.58.55 AM.png - 130kB

arkoma - 16-12-2015 at 05:07

yup, thats it. fixed temp but cheap and not a fire hazxard

Praxichys - 16-12-2015 at 05:31

I have an earlier model of this, which has a built-in temperature control:

http://www.amazon.com/Presto-Options-Electric-Multi-Cooker-S...

It's not too much more expensive (~$25) and it will hold temps within about 5C from about 80C to 230C. (graduated from "simmer" to 450F). I got mine for free from a burned-down house but I see them all the time at the goodwill store for about $5.

Detonationology - 16-12-2015 at 05:35

I assume that the Fry Daddy is capable of achieving higher temperatures than a standard crockpot, correct? I've only seen crockpots at my local thrift shops.

bluamine - 20-12-2015 at 13:03

Quote: Originally posted by chemrox

Do you have heater? Mine was deep fat fryer. It is amazingly precise in temperature control. I can heat 10 ml t0 2000 ml rb flasks. I can hold the oil +/- 1*C!!!
I use diethyl pthalate for the "oil." It doesn't smoke below ~ 300 *C but I try to use it in the hood for higher temps. For some reactions I prefer it to heating mantles. I found it at a garage sale. It hadn't been used. Pure serendipity.

Yes i do.. & thanks for informations

bluamine - 20-12-2015 at 13:05

Quote: Originally posted by JJay

It is usually recommended to use mineral oil, which has similar properties to diethyl pthalate. Vegetable oils are generally cheaper and easier to obtain. Under 200 C or so you can use a vegetable oil with a high smoke point. I often see people on here use expensive oils with low smoke points (like peanut, canola, olive, etc.) - but soybean oil is cheap and good to fairly high temperatures. It is sold as "vegetable oil" in the United States. You can use a search engine to find the smoke point of any particular oil.

I usually heat my oil baths with immersion heaters.

Why are smokeless oils preferable?!
I read about using glycerin but I would prefer nitroglycerin

[Edited on 20-12-2015 by bluamine]

bluamine - 20-12-2015 at 13:09

Quote: Originally posted by Praxichys

Thanks bro. I will check them later. It is too late here now..

The_Davster - 20-12-2015 at 13:10

Quote: Originally posted by bluamine

Why are smokeless oils preferable?!

you will find out the first time you use a non-smokeless oil. It will make a TON of smoke

[Edited on 20-12-15 by The_Davster]