Sciencemadness Discussion Board

Making chloroform but bp is 49 °C

vmelkon - 8-3-2013 at 10:47

I have been making chloroform using Ca(OCl)2 and acetone. I first dissolve the Ca(OCl)2 in water and then add the acetone. I assume that the Ca(OCl)2 is 75% pure in my calculations. It obviously contains some Ca(OH)2.

The liquid (chloroform) I collected is obviously denser then water. I know because water floats on top of it.

I took the liquid (20 mL) and distilled it but there is something that distills at 49 °C. What is it?

CHCl3 bp = 61.2 °C
propanone bp = 56-57 °C
chloroacetone bp = 119 °C

DraconicAcid - 8-3-2013 at 10:58

Can you measure the density? Dichloromethane has a bp of 40 oC, but I'm not sure how you'd get that from this reaction.

vmelkon - 8-3-2013 at 12:27

I could. I need a couple of days to make some more.

AndersHoveland - 9-3-2013 at 00:20

It could be some condensation product between an aldehyde and alcohol.
Dimethoxymethane sublimes at 42 °C, for example.

vmelkon - 10-3-2013 at 15:55

I think it was because I was applying low heat so the vapors coming up were cooling as they rised.
I collected enough liquid and distilled "strongly" on its own. bp = 59 to 60 °C.

Density = 1.3984375 g/cm3 (3 digit approx = 1.40 g/cm3)

===================
CHCl3 bp = 61.2 °C
Density = 1.483 g/cm3

propanone bp = 56-57 °C
Density = 0.791 g/cm3
===================

So my chloroform has some acetone I guess.

Trichloromethane purification problems?

Dariusrussell - 25-9-2013 at 12:21

So I did the NaClO and Acetone route to producing trichloromethane. As it is distilling now, I have a significant amount of liquid (15mL plus) that is boiling at 50C (My thermometer is pretty crappy so anywhere from 45 to 55)

It smells slightly sweet and has a bite like an alcohol (Like smelling methyl Salicylate)

I haven't smelled pure chloroform before and this boiling point is on the low side?

Is this my product? Or is it an impurity? It also doesn't look quite as refractive of pictures I have seen, but is still very refractive

Dariusrussell - 25-9-2013 at 12:23

Or actually if anyone has any easy tests (Other than smelling large quantities) for my product.

kristofvagyok - 25-9-2013 at 12:30

Thermometer often lies, check its density. Take out 10 cm3 and weight it. If it is near to 14,8 g, than you got it.

But according to the sweet smell, and knowing that this reaction is pretty selective, you should have some chloroform.

Dariusrussell - 25-9-2013 at 12:36

Haha density, I should have thought of that.
I got 1.44g/mL which is definitely close enough, Stupid me.
In fact, I added some insulation around the top joint and the temp has already risen to 56 and rising.
Bfesser, you may close this thread

[Edited on 25-9-2013 by Dariusrussell]

Dariusrussell - 25-9-2013 at 14:08

Ok distillation done. I took a second density and ended up with 1.40 which is way low. This is most likely due to the fact that I messed up my stoichiometry and added more 10g of acetone then there needed to be, knowing acetone and chloroform form an azeotrope (80%acetone 20% chloroform) that boils at 64ish degrees, I theorize that I have a around 10g acetone in the mixture.

Here are some pictures of the (anti)purification:


I stored it in a UV blocking bottle, don't worry!



Would this acetone impurity render the solvent useless? Is there a way to extract it?
Thanks, Darius

papaya - 25-9-2013 at 14:15

More acetone you say, then why not react the excess with more NaOCl NOW? I mean "wash" your chloroform with bleach.

macckone - 27-9-2013 at 09:03

If you used insufficient hypochlorite, you probably have a lot of impurities. The ones I can think of are acetylaldehyde, dichloromethane, acetone, chloroacetone (mono and di varieties) and smaller amounts of formic acid, acetic acid, formaldehyde, chloroacetic acid and possibly condensation products. Since chloroform loves forming azeotropes, you probably have a good mix of stuff. The previous poster suggested adding more hypochlorite which is probably the best solution.

vmelkon - 3-10-2013 at 16:50

Quote: Originally posted by macckone  
If you used insufficient hypochlorite, you probably have a lot of impurities. The ones I can think of are acetylaldehyde, dichloromethane, acetone, chloroacetone (mono and di varieties) and smaller amounts of formic acid, acetic acid, formaldehyde, chloroacetic acid and possibly condensation products. Since chloroform loves forming azeotropes, you probably have a good mix of stuff. The previous poster suggested adding more hypochlorite which is probably the best solution.


I don't think you'll get some of those products that you listed like acetylaldehyde and dichloromethane, formic acid, acetic acid, formaldehyde.