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Theoretic
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I was once flicking through a book - a dictionary of science and technology. In the section for chloroform it stated the technical preparation as
being alcohol + + calcium hypochlorite. Here's the equation I concocted myself:
2C2H5OH + 5Ca(ClO)2=>2CCl3H + + CaCO3 + 2CaCl2 + Ca(OH)2 + 4H2O.
I wanted to do it myself with technical azeotropic alcohol and bleach which contains 6% NaClO and asked my dad for help, but he rejected it altogether
- said that I couldn't do it inside a house. I wonder if chloroform really could evaporate during preparation?
Fortunately he works in a place with a lab, so maybe I could carry it out after all.
2C2H5OH (1.84g.) + 10NaClO(14.9g. - 228.00ml. 6% bleach) =>
2CCl3H (4.78g.) + 2Na2CO3 + 4NaCl + 2NaOH + 4H2O.
[Edited on 11-11-2003 by Theoretic]
[Edited on 11-11-2003 by Theoretic]
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Theoretic
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Well, what can I say? NULL AND VOID. A failure. I've done it at home, my dad wouldn't let me do it in the lab. My materials were
">5% Sodium Hypochlorite" bleach and azeotropic alcohol. So, I start dropping the alcohol slowly into the bleach (the whole lot in a 100
ml flask). I see convection. My initial thoughts were that it's caused by the heat of the reaction, but no. Nothing. I make a water bath, fill it
with boiling water and put the flask in it. it had a low capacity though, so i changed the water periodically. I kept it that way for 40 minutes or
so, and nothing happened.
Morale: having only impure dilute crap and the equation, you can't carry out a reaction with a C-C bond cleavage.
Anyone with calcium hypochlorite (solid or concentrated solution) and a proper water bath volunteer to do it? 
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Theoretic
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Cheer up! I found a preparation of chloroform from calcium hypochlorite and acetone. It's in Russian, but don't worry about my translating
skills.  First preparation of Ca(ClO)2 is described. I calculated that 28.6 g
of Ca(ClO)2 is made. In the mixture there's also 30-40 ml water (keep this in mind). Then:
"Put the prepared bleaching powder in the flask of the apparatus pictured on pic.2. Also put there 75 ml of water. Put a mixture of 10 ml of
water and 10 ml of acetone in the dropping funnel. The end of the dropping funnel must be lower than the level of liquid in the flask. Put 10 ml of
water in the receiver to preserve the prepared chloroform from evaporation and to guarantee it's purification from acetone. Start introducing
acetone drop by drop into the flask, heating the flak with the aid of a flask heater. If the reaction is too vigorous and the reaction mixture starts
splattering into the reciever, heating of the flask should be stopped."
Then the drying and distilling of the chloroform is described.
At http://www.chem.msu.su:8081/rus/teaching/aleshin/chcl3.html are the drawings and the original text.
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Theoretic
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OK, I did sound too cheerful, because while I was typing about acetone + Ca(ClO)2 while thinking about alcohol + Ca(ClO)2.  But with
definite instructions the yields will be improved. I surfed a chemistry book recently, and yes, it is: (CH3)2CO + 3NaClO => CHCl3 + CH3COONa +
2NaOH. Also I know of a reaction in which carboxylic acids are fused with alkali hydroxides, and an alkane and alkali carbonate form. So
trichloroacetic acid + NaOH => chloroform + sodium carbonate.
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Hermes_Trismegistus
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Whoa Nelly!
| Quote: | Originally posted by Samosa
I don't think that Chloroform is the best "knock-out" chemical; I remember NBK2000 talking about a time when he held a rag of
Chloroform to his face for a minute, breathing deeply, and he was quite conscious.
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I will not say I disbeleive NBK2000 because no-one ever lies on these forums, but I will say that NBK2000 is a tough son-of-a-bitch. I took a couple
good whiff off of the soaked end of a Q-tip............WOW!!!
I am wacked! Sleepy, heavy eyelids, feeling sorta drunken and dull-headed.
Perhaps NBK2000 has some sort of cross tolerance that helped to resist chloroform, because I weigh well over 255 and it hit me like a hammer. The
only difference I could see is that I don't use any sort of drugs at all, nor do I ever drink.
Still....I must say, chloroform has this strange allure to it. Almost a magnetic draw to continue breathing in the lovely vapours. Like the waters of
Lethe...
P.S. burning the substance on a watchglass produce a very black smoke and an odor very similar to the somewhat metallic smell of a roll of used paper
caps.
Also...repetition of exposure to fumes definitely seemed to produce a tolerance to the narcotic (sleep inducing) effects.
[Edited on 21-12-2003 by Hermes_Trismegistus]
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BromicAcid
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Seeing as how this thread is dedicated to experiments with chloroform I thought that it might be interesting to metion that the interaction of
chloroform with acetone in the presence of solid KOH, NaOH, or CaOH, violently leads to the formation of 1,1,1,-trichloro-2-hydroxy-2-methypropane.
An interesting chemical, although like I just said, the reaction is violent.
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blazter
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the reaction wasn't violent for me...
I have previously posted my experiment to produce what I hoped to be chlorobutanol. It was done at low temps IIRC and used a makeshift overhead
stirrer to aid the reaction. The reactants were chloroform, acetone, and NaOH. In the end I got a few grams of sticky crystals which had a strong
'camphor' odor. The fact that I didn't get a clean crop of crystals suggests that a mixture of things were formed, though I am not
sure what these different products were.
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Hermes_Trismegistus
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| Quote: | Originally posted by BromicAcid
Just for completeness I would just like to say a word about the reaction. It is a haloform reaction, it oxidizes methyl groups directly attached to
the carbon that makes up the double bond to oxygen in a ketone. It takes place under basic conditions in the presence of halogen so the hypochlorite
salts are perfect for this. When the reaction is over you have the oxidized ketone minus one carbon which in the case of acetone would be CH3COOH but
you could use say Methyl-ethyl ketone and get CH3CH2COOH so it's good for making carboxylic acids (In the above reaction they would end up as
their sodium salts) so the overall reaction goes:
CH3COCH3 + 3NaOCl ----> CH3COONa + CHCl3 + 2NaOH
With some NaCl and such thrown in for flavor. By the way, I don't think the above reaction is entirely correct... I've got different
numbers in my notes but I don't know where they came from. I'll update my post if I find the source again. So basically you can use any
basic enviorment with free halogen thrown in, so you can get bromoform and iodoform but I don't think fluoroform, free fluorine would not take
well to an aqueous enviorment, also it is a decent way to make carboxylic acids. |
pardon, but would not CH3COONa ----> CH3COO- + Na+. Na+ + H2O
CH3COO- is the anion of the weak acid, acetic acid, therefore its conjugate base is stronger and will react with water to produce more OH- ions.
maybe...?
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Hermes_Trismegistus
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| Quote: | Originally posted by BromicAcid
Seeing as how this thread is dedicated to experiments with chloroform I thought that it might be interesting to metion that the interaction of
chloroform with acetone in the presence of solid KOH, NaOH, or CaOH, violently leads to the formation of 1,1,1,-trichloro-2-hydroxy-2-methypropane.
An interesting chemical, although like I just said, the reaction is violent. |
with chloroform stored in a bottle with any aqueous sol'n floating on top containing NaOH it would be possible that the water in the aqueous
sol'n would evaporate off. leaving solid NaOH right? then say you had a little excess acetone in sol'n you could have an unwanted
reaction....
so I am thinking that I'll wash my chloroform with several volumes of water before storage.
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DDTea
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Don't forget to add a small amount of Methanol to your Chloroform before storage, and to keep it out of light! These are important to prevent
the decomposition to Phosgene, as tends to happen in storage. The Phosgene forms a cloud at the top of the container, and the operator tends to be
exposed to it on opening the container...hence many stories of workers using Chloroform getting sick.
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Hermes_Trismegistus
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storing chloroform / trichloromethane
I do not have ground glass stoppered reagent bottles
I have found (after significant evaporation losses) that storing the chloroform in glass jar/bottle under a layer of about a half inch of (preferrably
distilled) water both vastly reduces losses and increases safety. It's probably a common trick but it was a definite EUREKA! moment for me
I am still storing the container cold but have found that if the water freezes that the plug of ice sinks a little into the chloroform and then the
chloroform evaporates off the top again (albeit more slowly because of reduced temperatures)
[Edited on 4-1-2004 by Hermes_Trismegistus]
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The_Davster
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I made some today, 500mL 5.25% NaOCl bleach solution, and about 4/5 of a film canister full of aetone(dident feel like washing out a graduated
cylinder). I had no means to store it because I had no suitable glass bottle, my yield was about 5-7mL. what has been everyone elses yield who has
tried it?
Also any tips on getting all the small droplets of CHCl3 into one big blob(I had 1-2mm droplets covering the bottom of the beaker and 1 big blob), I
had a few extraction problems because of this.
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Hermes_Trismegistus
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perhaps read both threads full through next time!
| Quote: | Originally posted by rogue chemist
I made some today, 500mL 5.25% NaOCl bleach solution, and about 4/5 of a film canister full of aetone(dident feel like washing out a graduated
cylinder |
Film Canister is approximately two fluid ounces, far too much acetone for 500mls Chlorox.
I remember someone mentioning that to be a BAD thing indeed!
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The_Davster
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Im not too good with estimating volumes, today I put 10 ml of water in a film canister and it was much less than I had origionally thought(about 1cm
in bottom).
The batch I made I did not bother keeping because I had no suitable storage containers, or methanol, so I was not worring about contamination that
could cause problems during long term storage. Next time, when I make a batch that I will keep/store I will make sure to take all the necessary
safety precautions.-this was essentially a test batch before I get my amber glass bottle.
And I did read the entire thread many times before making the CHCl3.
[Edited on 6-1-2004 by rogue chemist]
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Haggis
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The reason you got roughly the same yields as I did with around 4 times as much acetone is because the availible chlorine for the haloform reaction
was used up. If you had a larger concentration of hypochlorite, you would, of course, get more. I would just say add more acetone and get the max,
then adding too little, and not getting what you can. I wouldn't think that it would be too bad, excess of acetone, it would just mix with the
water and be held up in the water from the bleach.
Great ideas often receive violent opposition from mediocre minds.
<b> <a href=\"http://pgp.mit.edu:11371/pks/lookup?op=get&search=0xEE41A2B1\">PGP Key</a> </b> 0C0A 7486 B97F
92EE AE50 A98C A4F3 087E 8CE9 A782 |
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The_Davster
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purification
To prepare CHCl3 for storage, would it be sufficient to mix with about 200mL water, stir very well, let it settle to the bottom again and then
re-extract and add methanol? Hopefully this would remove any impurities imparted to it from the reaction mix.
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BromicAcid
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If there is too much acetone in the mix some of the acetone only gets partially halogenated and will not form the chloroform because, well, although
each substitution makes the molecule more susceptible if there is a great excess it doesn't matter how much more susceptible because there will
be no more hypochlorite left. Too much hypochlorite and reactions start to happen with the chloroform to form carbon tetrachloride. Stoichiometric
amounts are necessary for the highest yield as is efficient cooling, the reaction does heat up and the boiling point of chloroform is not negligible
under these circumstances.
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Hermes_Trismegistus
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| Quote: | Originally posted by rogue chemist
Im not too good with estimating volumes, today I put 10 ml of water in a film canister and it was much less than I had origionally thought
no suitable storage containers, or methanol, .
And I did read the entire thread many times before making the CHCl3.
[Edited on 6-1-2004 by rogue chemist] |
I beleive you, Its hard to keep everything in your head at once, I keep the Lab Notebook as constant companion in Lab, hate when I forget whether I
NEED to perform the next step, or whether I just DID perform that step.
anyway, you don't need methanol to stabilize the chloroform, ethanol will do you, and is the additive normally used to stabilize (Merck Index
~1997)
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The_Davster
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Well, I have purchased an amber glass bottle(50mL) and already havemethanol, will this be sufficient to complety stop the reaction to phosgene or will
there still be some phosgene produced?- And if not is there anything else I can do because I really dont want any phosgene around
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BromicAcid
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I believe if the chloroform is anhydrous then there will be basically zero phosgene produced in that enviorment.
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The_Davster
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I'm not really sure how to dry liquids.
Would It be sufficient to add NaOH or NH4NO3(only dessicants I have at the present time) and then filter to remove any water present?-or am I missing
something obvious here which would prevent this from working?
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Hermes_Trismegistus
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Oh Yeah!
You often don't actually want to admix the dessicant and the substance to be dried. Because sometimes the substance (chloroform in this case) may
dissolve, or react with the substance you are drying.
Check for compatibilities
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Ramiel
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Yea, in this case especially, TCM is incompatible with strong bases.
I've come to report on the TCM via ethyl alchohol idea:
I dissolved 30g of Calcium Hypochloride in 500mL of water (you guessed it! in a jam jar!). The mix was heated, cooled, and filtered to leave only the
CaHypochloride soln. To this was added a stoichiometric ratio of Ca(OCl)<sub>2</sub> 6:1
C<sub>2</sub>H<sub>5</sub>OH in the form of absolute ethanol diluted to 50%. the ethanol was added dropwise, but no increace
in tempurature was noted.
I covered the stinking mix and left it for an hour.
One hour later it was dinner time.
Two hours later, no real difference was noted.
Twenty hours later, there was a scummy layer, a colloidal substance that looked like fluffy crystals, but no imiscible layer of potential TCM. The
mixture was pleasant to smell, and I was tempted to just keep drinking in the vapors.
here is what F.I.Luknistii had to say in the 75th volume of "Chemical Reviews" about chloral:
"When ethanol is heated with calcium hypochlorite, one obtains chloral and also chloroform, dichloroacetaldehyde, and the hemiacetal of
chloroacetaldehyde. Ethyl hypochlorite was proposed as the intermediate chlorinating agent in this reaction and acetaldehyde (with vinylic alcohol) as
intermediates. At 20" trichloroacetic acid is obtained in-stead of chloral."
(Thanks to polverone I think for the PDF)
I tested the solution with resorsinol and the colloidal crap turned from white to a bright orange - clearly discernable from the resorsianl. I propose
that the flocculant material was in fact chloral (CCl<sub>3</sub>CHO), and the sweet, ester smelling scummy top layer is a mystery.
I really dislike the whole reaction - a little huff (axehandle save my lungs) knocked me out, I slept for an awful 16 hours with bad dreams and
delerium. I have serious tremmors - which are brought about in my case only by chemical inhibition.
I will not try heating absolute ethanol with excess solid calcium hypochloride, but I suspect that this reaction would yeild a lot of chloroform and
chloral.
[Edited on 9-3-2004 by Ramiel]
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Quantum
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I made some trichloromethane today. 500ml of store NaOCl(6%) was dumped into my 500ml flask(no jam jar for me) 10ml of
CH<sub>3</sub>CCH<sub>3</sub> was poured into the flask and I dropped a thermometer in the top. I stirred the flask contents
around and watched the thermometer rise up to about 40C where I then placed the flask in the ice/water pan I had made. The reaction cooled and I
watched TV for awhile. I poured the whitish liquid out into the ice bath and saw an oily liquid form at the bottom. I extrated it with my shitty
plastic seringe(Soon I will get real pipits!) I placed a little on a strip of paper and took a good wiff. I smelt a strange smell that did not smell
like NaOCl or Propanone. However it did not have the effect that people said it does for me. I did not feel dizy and after letting fumes rise up into
my eye my eye on felt mildly strange. I may have got a contaminated or low yeild because of dyes in the bleach or not letting the reaction go long
enough. I have no amber glass bottle so I poured the trichloromethane out at the back of my property in the woods. I should have done a density per ml
check I guess.
What if, what is isn\'t true?
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The_Davster
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I recently obtained some 65% Ca(OCl)2. I tried using it to make chloroform. I used 41g of the hpochlorite and 10mL of acetone. I Disolved the
hypochlorite in the minimum amount of water necessary and while swirling in a RBF under a stream of cold tap water I added the acetone drop by drop
over a period of 10min. I let the reaction sit in cold water for about 20 min. when I got back there was a lot of white precipitate(calcium
hydroxide), and the distinctive scent of chloroform. But unfortunatly the chloroform is stuck in that layer of calcium hydroxide. How can I get it out? Filtration did not work, I tried adding nitric acid to a sample
to dissolve the hydroxide but that caused chlorine to be released and the small ammount of chloroform that became obvious after the nitric addition is
bright yellow.
[Edited on 18-4-2004 by rogue chemist]
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