------------------------------------------------------------------------------- Synthesis of 1,1,1-Trichloro-2-methyl-2-propanol (Chlorobutanol) ------------------------------------------------------------------------------- Chlorobutanol is prepared by the addition of chloroform to acetone under the catalytic influence of powdered potassium hydroxide, It has a local anaesthetic potency to a mild degree and is used as an anaesthetic dusting powder. Chlorobutanol has also antibacterial and germicidal properties. Using a molar ratio of 10:1, 45.0 ml acetone was reacted with 5.0 ml chloroform, varying other reaction conditions produced the following results: ------------------------------------------------------------------------------- Experiment KOH Time Temp Yield ------------------------------------------------------------------------------- 1 2.0 g 2 h -5°C 69.3% 2 1.0 g 2 h -5°C 71.0% 3 0.5 g 2 h -5°C 51.9% 4 1.0 g 1 h -5°C 68.4% 5 1.0 g 2 h 0°C 63.2% ------------------------------------------------------------------------------- Experimental: 45 ml Acetone, 5 ml chloroform and 1 gram powdered potassium hydroxide was mixed in a 250ml flask, and the reaction mixture was stirred at -5°C for two hours. The resulting suspension was filtered, and the filtrate was freed from excess acetone by distillation. The yellowish oily residue was mixed with 50ml of ice-cold water and chlorobutanol hemihydrate precipitated as a white crystalline material, which was filtered off and dried (preferably in a vacuum desiccator). Yield 71% of theory, melting point 78.4°C after recrystallization from water. Ref: Monatshefte für Chemie 114, 813-816 (1983) =============================================================================== Chlorobutanol - an alternative to chloral hydrate Updated - under continual revision. After translating the pertinent section of the original 1881 article on chlorobutanol, aka acetonechloroform, by Willgerodt from the German (using a crackz version of the SYSTRAN translation software, aka the engine behind Altavista's Babelfish), & the Beilstein German-English chemistry dictionary at: http://www-sul.stanford.edu/depts/swain/beilstein/bedict1.html I have some very important additional notes on the synthesis of chlorobutanol: 1. I recommend that once one has distilled off the acetone, POUR THE REMAINING LIQUID CHLOROBUTANOL INTO ~200ml OF ICED WATER, preferably with ice pieces still floating about. After several attempts of pouring room-temp water into the liquid chlorobutanol, the solid chlorobutanol would not crystallize out, and all you get is an oily layer that's hard to isolate. USING ICE WATER, I'VE GOTTEN WELL FORMED CRYSTALS EVERY TIME. You get nice slightly yellowish to white crystals. 2. Contrary to what I advocated earlier, I think it best to isolate the chlorobutanol from the ice water by filtration. Several attempts to directly crystallize liquid chlorobutanol from the fraction remaining after distillation, with ethanol and/or acetone, were dismal failures. The chlorobutanol "oiled" out (to use a term from my organic chem lab textbook) and would not crystallize. 3. You will probably want to re-crystallize the crystals isolated from the ice water, as they are usually overly hydrated, and never seem to fully dry. I recommend using ethanol. Although Willgerodt noted "beautiful crystals" from ether, alcohol, glacial acetic acid, acetone & chloroform, and poor crystals from petroleum ether & benzene, my personal experience is poor, oily crystals from acetone and/or chloroform. Ethanol, by far, gave beautiful white crystals. Be sure to use as little solvent as possible to dissolve the chlorobutanol before re-crystallization. 4. Chlorobutanol has a very strong camphor-like odor. Some people may find it rather pleasant. In any case, because chlorobutanol sublimes so easily, it is highly detectable in closed areas, so keep in a closed [glass] container after it has been crystallized/ recrystallized. For this reason, you may want to work with batch quantities of materials in open areas. I have found that people can detect its odor at least an hour after working with batch quantities of chlorobutanol. 5. Chlorobutanol, along with its camphor-like odor, also has a somewhat astringent camphor-like taste. It also has a astringent aftertaste that can persist for a time. I've found that foods with a higher fat content, such as peanut butter or ice cream, can mask and/or dispel this astringent aftertaste. Chlorobutanol can also have a mild numbing, local anesthetic effect on the tongue & mouth. Chlorobutanol was at one time medically employed for this local anesthetic effect. ------------------------------------------------------------------------------- Chlorobutanol, aka, chloretone, 1,1,1-trichloro-2-methyl-2-propanol, is a chloral hydrate derivative, both being metabolized to the same active principal, trichloroethanol. According to an older edition of a standard medical pharmacology textbook, chlorobutanol "is qualitatively similar to, but more potent than, chloral hydrate in its action upon the CNS..." and "unlike chloral hydrate, chlorobutanol produces no gastric irritation, and toxic rxns following the administration of therapeutic doses are extremely rare." (Drill, Pharmacology in Medicine, 2nd ed., 1958, p.156). The synthesis of chlorobutanol is quite simple, provided you can get one of the key ingredients, chloroform. The other necessary ingredients are acetone, potassium hydroxide, ethanol & water. For you organic chemists, this is a simple nucleophilic addition of the trichloromethyl anion to the carbonyl bond of acetone in the presence of a strong base. The preferred synthesis is that described by Fishburn & Watson (J. Amer. Pharmaceut. Assoc., 28, 491-3, 1939) (I haven't found any more recent syntheses or variations): (Verbatim, modified into an 'outline format'): "We recommend the following procedure for the preparation of chlorobutanol. One hundred grams acetone (5 mols) and 40 Gm. Chloroform (1 mol) are mixed, and 7 Gm. potassium hydroxide (5%) dissolved in the minimum quantity of alcohol, are added. The addition occupies fifteen minutes; cooling is usually unnecessary. The precipitated potassium chloride is filtered off and washed with a little acetone. The filtrate is distilled on the [boiling] water-bath and when no further liquid distils, about 200 ml. of [distilled] water are added. The chlorobutanol is filtered off as a white solid. Yield (calc on CHCl3), 25% theoretical. The acetone distilled off [can be] used in a subsequent preparation." Chlorobutanol is slightly soluble in cold water, more soluble in hot water, and readily soluble in ethanol (acetone, chloroform and numerous other organic solvents). Notes: 1. Potassium hydroxide is preferred over sodium hydroxide, as the former is more soluble in ethanol. However, the original authors found that "sodium hydroxide is almost as effective as potassium hydroxide" and is a lot easier to obtain. 2. You CAN USE denatured alcohol (ethanol), as it is only used as a carrier solvent, and the TOXIC methanol is evaporated off with the ethanol during the synthesis. DON'T DRINK DENATURED ALCOHOL. The added methanol is TOXIC. 3. 100 gm acetone = ~125 ml. (density = 0.79 gm/ml) 4. 40 gm chloroform = ~26.7 ml (density = 1.48 gm/ml) 5. I assume you could use the same amount of NaOH as KOH, as the base acts only as a catalyst for the rxn. Both reagent grade KOH and NaOH contain small amts of their respective carbonates, which are insoluble in ethanol. Therefore either base will never appear to totally dissolve in ethanol. Dissolve as much as you can, and add everything to the acetone-chloroform mixture. The carbonates will not interfere with the rxn, and will be filtered off with the chloride salts. 6. This author distilled the rxn filtrate using a distillation flask in a common kitchen hot pot which functioned as the boiling water bath. DON'T DISTILL THE ACETONE NEAR ANY OPEN FLAME. The remaining liquid is actually liquid chlorobutanol. The water cools the liquid, and allows it to solidify. Allow the mixture to cool until no more chlorobutanol solidifies out of solution. The crude product is usually yellowish to off-white. Re-crystallization (see note 7) usually clarifies the end product to a white solid. 7. It was found that re-crystallizing the product from ethanol gives a much cleaner product. The original product contains excess water, and is somewhat oily to the touch. Dissolve the product in the minimum amt of ethanol and allow to evaporate dry as a thin layer on a "large" glass plate. Scrape off the re-crystallized chlorobutanol with a razor blade or other sharp straight edge. Store the chlorobutanol in a closed dark container, as it sublimes easily. 8. The astute organic chemist will note that the experimental ratio of acetone:chloroform is 5:1, while the theoretical ratio necessary is 1:1. The original authors found that this ratio gave the maximum yield. This is due to various side rxn's that also take place. 9. As mentioned above, the best yield the original authors could obtain was 22-25% of the theoretical. They attributed this to the harsh basic conditions which the rxn requires. They tried weaker bases, and were unable to get any rxn to occur. The present author obtained similar yields, but suggests that you don't re-use the acetone distillate too many times, as yield appears to decrease. 10. The recommended dosage range is about the same as for chloral hydrate, 0.25 to 1.25 gm. (Drill, op cit.; Merck Index). It does work, and in the higher dosage range results in a groggy, stuporous state. (AB)USE AT YOUR OWN RISK. ------------------------------------------------------------------------------- (19.7.99-added caveats, corrected text) 1. The filtrate from filtering off the water from the chlorobutanol contains significnat quantites of chlorobutanol. Further crystals can sometimes be found in this so-called 'mother liquor' (from from organic chem lab text) if it is re-cooled. Chlorobutanol is slightly soluble in room temp water (1g/125 ml, Drill, Pharmacology in Medicine, 2nd ed., 1958, p.156). 2. From the previous caveat, save the filtrate. There is sufficient chlorobutanol dissolved in this 'mother liquor' to make you stuporous. It has a oily, camphorous taste, best consumed cold, with some substance to disguise the bitter taste. 3. Since I've never actually experienced chloral hydrate, I can best describe the effects of chlorobutanol as effecting motor function before cognative function. In other words, you know you can't walk a straight line very well, but you can still comprehend a textbook. =============================================================================== From "Recreational Drugs" by Professor Buzz: Chlorobutol (Chloretone) 1 mole of dry acetone and 2 moles of chloroform is cooled to 10°C with good, constant stirring. To this mixture add finely powdered KOH (20% by weight of the above mixture), at a slow rate to keep the reaction temp below 50°. Continue to stir and cool for 24 hours more. Filter the mass and wash with acetone. The filtrate and washings are bulked and distilled, and the fraction boiling at 165-175°C) is collected in water. The hydrate is filtered and recrystallized from 50% ethanol. mp: 77-78°C. Chlorobutol is a mild hypnotic with analgesic properties, used in seasickness, persistent hiccupping, and irritations due to chronic skin diseases. Dosage: 0.3 to 1.2g -------------------------------------------------------------------------------