What kind of lab thermometer do I need?

[Elijah Phoenix]

So I decided to buy a thermometer but realize I must buy one that is not only accurate but appropriate.

I will be using for vacuuming diztillation. Do I need full immersion or just partial? May a brand be recommended here? I feel I need one that reads up to 200 Celsius for higher BP's of various things.

Can someone please confirm what I really am supposed to use? I really want to make an educated acquisition.

Thanks in advance-

 

[1ce]

Use either red spirit or mercury thermometers. During vac distillation bp temp changes and this can offer room for inaccuracy. I perfer mercury for better accuracy and use red spirit for close approximations since they're dirty dirt cheap. All lab thermometers will have immersion lines but those are used to check internal liquid temperature, often during reactions (typically).

You can use a nomograph to find the bp of your liquid at various pressures. Best practice is to use a manometer to gauge pressure during distillation. Record the distillation start/stop point at the pressure you were using as a reference point.

Is there anything else you needed to know?
Regards, 1ce

 

[MaNoMaNoM]

i think the infa-red/laser thermometer looked cool,
and practical because you don't dip it in anything.
They are only 10$ on ebay, SO it's on my wish list.

 

[benzyme]

i also have a couple IR thermometers, the Fluke being the more accurate one (it also has a port for K-type thermocouples). the outside surface temp of the rbf won't differ much from inside the flask.

 

[1ce]

i also have a couple IR thermometers, the Fluke being the more accurate one (it also has a port for K-type thermocouples). the outside surface temp of the rbf won't differ much from inside the flask.

True, but nothing tops good'ol mercury for collecting distillate at a 1.5-2 degree range. :3

 

[BubbleCat]

I am very very happy with a set of 10 mercury ones I once bought, they were old stock from soviet union, I did not yet manage to break them all, they range to 230 C I got them of eBay for about 30$ the lot. Recently I have also bought myself a red spirit one ranging to 400 C but that has no use in anything of interest on this forum.

Mercury ones might be a health and environment hazard, keep that in mind. The modern red spirit ones are awesome, cheap and precise.

I can not exactly imagine how I would use the IR thermometer in the lab to be honest, but I think thats the point: Find what fits you

 

[benzyme]

you use it to measure surface temps, of course. just adjust the emissivity accordingly.
i use them primarily for sublimations and vac distillations, Hg thermometer for normal distillations.

 

[1ce]

you use it to measure surface temps, of course. just adjust the emissivity accordingly.
i use them primarily for sublimations and vac distillations, Hg thermometer for normal distillations.

I never thought about using IR to vac distill =O

 

[BubbleCat]

I see now that makes perfect sense

 

[Elijah Phoenix]

Thanks for the quick answers. I would like to start of using a regular thermometer vs an IR. But I would indeed have many uses for an IR; tea, soap, etc.

1ce, I appreciate the concise advise! I'm going to avoid the mercury one for the time being, as i don't think I'm prepared to clean up that kind of mess if it happens. I do want accuracy though, this is a great learning experience and there's so many fantastic uses for these tools.

I'm looking forward to setting up the distill for the first time. There is a certain epic nature to this equipment, and a satisfaction that is yet to be fully realized.

 

[1ce]

I compare learning to distill to getting your driver's license, it opens up alot of freedom.