Author Topic: Home Made Chloroform and Iodoform  (Read 4235 times)

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lugh

  • Guest
Liebig and Dumas's Version
« Reply #20 on: August 02, 2004, 06:02:00 PM »
This prepartion of chloroform claims a slightly higher yield compared to the very similar procedure from Mann and Saunders in

https://www.thevespiary.org/rhodium/Rhodium/chemistry/chloroform.html

, by increasing the amount of hypochlorite relative to acetone  ;)
 
From Cohen's Practical Organic Chemistry

Chloroform (Trichloromethane), CHCl3.
Liebig, Pogg. Ann., 1831, 23 444; Dumas, Ann. Chim. Phys. 1834, 56 115.
200 grms. bleaching powder (fresh). 800 c.c. water.
40 grms. (50 c.c.) acetone.
A large round flask (4 litres) is fitted with a cork, through which a bent tube passes connecting the flask with a long con­denser and receiver. The flask is placed upon a large sand­bath. Grind the bleaching powder into a paste with 400 c.c. Of water and rinse it into the flask with the remaining 400 c.c. Add the acetone and attach the flask to the condenser. Heat cautiously until the reaction sets in, which is indicated by the frothing of the liquid. Remove the flame for a time, and when the reaction has moderated, boil the contents until no more chloroform distils. This is easily determined by collecting the distillate in a test-tube and observing if any drops of heavy liquid are present. The distillate is shaken with dilute caustic soda solution in a separating funnel and the lower layer of chloroform run into a distilling flask. A few pieces of solid calcium chloride are added and left until the liquid is clear, when it is distilled from the water-bath with a thermometer inserted into the neck of the flask. Yield about 40 grams.
The bleaching powder acts as though it consisted of a compound of calcium hydrate and chlorine, and the process probably occurs in two stages.
1. CH3-CO-CH3+3Cl2=CH3-CO-CC13+3HCl
2. 2CH3-CO-CC13+Ca(OH)2=(CH3-COO)2Ca+2CHC13.
Trichloracetone is first formed, which is then decomposed by the lime into calcium acetate and chloroform.
Proterties.-Colourless liquid possessing a sweet smell, b. p. (60-62°; sp. gr. 1.498 at 15° ; very slightly soluble in water ; non-inflammable. As chloroform slowly decomposes in presence of air and sunlight into phosgene, it is usual to add a little alcohol to the commercial product, which arrests the change. Pure chloroform is neutral to litmus, has no action on silver nitrate solution and does not discolour concentrated sulphuric acid when shaken with it for an hour or left for a day.


8)


Xaja

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Cheapskates method
« Reply #21 on: August 02, 2004, 09:54:00 PM »
Cheapskates method was something like this, was on Rhodiums page once but I can't seem to find it there now...


yei

  • Guest
continuous reaction?
« Reply #22 on: August 05, 2004, 05:21:00 PM »
I wonder if it would be desireable to try and perform this reaction in a continuous reactor, like one of those spiral condensors, to limit its reaction rate. This might be useful for other reactions as well. (bromination/chlorination?)