Manufacture of Chloroform from Acetone and Bleaching-powder.
-This is the process most generally employed. The method differs in minor detail with the various manufactures, but the following may be taken as
representatives. The reaction is carried out in a cast-iron still of about 800 gallons capacity, which is provided with stirring gear, steam-coils,
and cooling-coils, and is connected with a condenser; 300 gallons of water are run into the still, and 800 lbs of bleaching powder are added through a
manhole, which is then securely bolted down. During addition of the bleaching powder the mixture is very thoroughly stirred. (In some processes the
mixing is carried out in a separate vessel, and the suspension is strained from the larger unbroken lumps of bleaching powder before being allowed to
run into the still.) The container (A in the diagram shown on p. 78) is charged with 70 lb of acetone, which is then slowly run into the
bottom of the still by means of a valve B. The introduction of the acetone is accompanied by a rise in the temperature which is not allowed
to exceed 110 F., cooling being effected if necessary by stopping the flow of acetone and circulating cold water though the cooling coil in the still.
When all the acetone has been introduced the contents of the still are raised to 134 F. At this temperature chloroform begins to distill over. The
temperature is then very gradually raised to 150 F., so as to keep the chloroform readily distilling. Towards the end of the reaction the mixture is
stirred and the temperature raised until no more chloroform distills over.
The crude chloroform obtained is separated and purified first by agitation with concentrated sulfuric acid. This operation is carried out in the
vessel shown in the diagram ; 1,500 lb. of crude chloroform are introduced into the vessel and thoroughly stirred, by means of the agitation gear
shown, with 600 lb. of sulfuric acid. The stirring is continued until a sample of the chloroform when thoroughly shaken with pure concentrated
sulfuric acid does not impart the slightest color on the latter. The time required for complete purification is usually about 3 hours. The
chloroform is next separated from the sulfuric acid and finally distilled over lime. The yield obtained from the above quantities averaged from over
2,000 batches was 124 lb., the highest yield in any one case being 131 lb. Variation in yield is attributed to the varying composition of bleaching
powder, though doubtless other factors influence the result. Bleaching powder containing less then 33% of available chlorine gives unsatisfactory
results, while samples containing more then 35% of chlorine are also unsatisfactory. The best results appear to be obtained with bleaching powder
containing 34% of available chlorine. |
What did I use as my reaction vessel? A quart mason jar! No need for using
graduations, just use the marks on the side of a beaker! I dump 500 ml of the solution into this large quart jar. I measure off 10mlof Acetone with
a graduated cylinder and pour this in a film can for easy pouring. I take this out to the garage, as I was a bit paranoid about fumes being evolved.
I slowly stir the acetone into the mixture with the metal wire used on those little flags people use to mark sprinklers in their yard. I stir this
for around one minute and the solution is the same color as the bleach in the first place, yellowish. Then as a minute nears, the solution turns
foggy, yet still yellow. Nearing 1:30-2:00, the solution starts turning white and foggy. At this point I felt the side of the jar, it was quite hot.
After some odd expression I probably muttered, I ran to the kitchen, where there was an ice cream bucket left over from a party or some thing. This
I quickly filled with cold water and placed the jar inside it. When I continued stirring, it felt almost 'frothy' when the wire was spun
back and forth in the solution. I later determined this is when the trichloromethane is being formed. I kept stirring for around 5 more minutes and
looked at the bottom of my jar. Upon tilting on its side, there was a nice, clear layer happily sitting on the bottom. Agitation of this blob
provided tiny bubbles raising up from the rest of the mass. I presumed this was either chlorine coming out of solution of vaporized trichloromethane
from the heat. I decanted off the whiteish liquid on top into the icecream bucket with the water. I then suctioned off the chloroform off the
bottom. Hurray! The scent is similar to DCM, and there is really no flammability. A bit soaked in paper towel and held to a flame will sizzle
slightly and occasionally give off a darker smoke/vapor. I do not know if this is the papertowel burning, or otherwise, but at one point, I sniffed
lightly the fumes rising above it and was hit with an odd sensation of burning, pain, shock, suffocation, and general suprise. Bad fumes 
. I went back and repeated the experiment many times, and found that same results
could be had with little input. Use a water bath for smaller batches like this, ice would be expensive (if bought). I would add reactants, stir till
it is white and cloudy and do something else. Then, come occasionally and stir a bit. I ended up banging this off quite quickly, and could do a
batch in about 10 minutes. Using the above amounts, I got yields around 4-7 ml. As said before, the yields arn't great, but everything is
common and most have the chemicals lying around. Improvements can be made using 10% hypochlorite solution, which they have at pool suppliers and
confirmed at my Ace or 'bleaching powder' which I have not encountered before. 
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