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I've had pretty shitty yields trying to make Acetamide at home. The amounts used in the reaction below were experimentally derived so your milage may very with the quality of starting materials. RatHead provided the motivation for this experiment and I desparately seek his or anyone's advice on how to improve it.
Materials:
Measure 42 mL Ammonium and pour into Jar #1. Put the jar in the freezer to chill. Measure 30 mL Glacial Acetic Acid, submurge entire glass graduated cylinder in large pot of cool water. For better stability, make sure no air bubbles are trapped under the base of the cylinder.
Place funnel into graduated cylinder so that the end extends well below the level of the Acetic Acid. Pour Aqua Ammonium into funnel, the first few drops will react very vigorously and may spit Ammonium back out of the funnel so slow at first or wear goggles. Execpt for the first little bit, the Ammonia can be added very quickly this way. Considerable heat is evolved but the water bath effectivly cools the cylinder. Bubbles are formed but are mostly absorbed by the liquid as they rise, this is the reason for the long funnel.
Once all of the Ammonium has been added (should take less than 1 minute) a sweet candy smell may be present in addition to the lingering smell of Ammonia. Don't put your nose over it just in case. Pour the solution into Jar #2 and repeat the process two more times. The time from start to clean-up is 30 minutes or less.
Ammonium Acetate degrades into Acetamide at 88°C. I don't really know how long it takes to happen so I guessed one hour. This is only a guess with no experiment to back it up. Anyway, pour the contents of Jar #2 into a boiling flask. Boil some tap water in the large pot that you used for a cool water bath in step #1. Heat the boiling flask containing the combined liquid from the three iterations of Step #1 in the boiling water for an hour. Don't let the water get into the flask, also don't let all the water boil out of the pot. If there is any excess free Ammonia it will boil out now so be prepared for a stink. Rigging up an odor control device now will also benifit you in the next step but it is not necessasary.
Set up your rig for fractional distillation with a water cooled condenser. The temperature will rise as you heat the solution, it will begin boiling in the neighborhood of 108°C but the temperature will quickly rise under strong heating until it gets to 118°C. It will stick at 118°C for a while as Acetic Acid comes over. Soon, the temperature begins to rise again and the smell, which until this point was getting better, will begin to get worse. Clear watery distillate will come over all the way up to 200°C. I don't know what it is but it smells pretty nasty. Third party noses have described it as the smell of "rotting ammonia" and "rotting food with ammonia". I think it smells like my urine after a night in the coffee house drinking java after java and smoking cigarettes.
Replace the collection flask when it gets to 200°C and collect everything between 200°C and 225°C. It is still a clear liquid and there is no doubt that there is some of that smelly stuff in there with it. Stopper the flask and set it aside to cool down. When it cools down somewhere below 80°C it will form white crystals.
If you just heat it to 200°C and keep everything that is left it will still crystalize but it seems to melt at a lower temperature and never be quite dry. Actually, you can usually stop heating at 150°C and it will crystalize at room temperature but it will melt in your hand. The MSDS for Acetamide says that it melts at 82°C.
Acetamide is a useful compound. When reacted with bleach, it makes methylamine gas. So you may say to yourself: "Damb! How do I get me some of that?". Aside from purchasing it, its incredibly easy to make!
44.055 g (0.5 moles) of ethyl acetate is combined at room temperature with 59 grams of concentrated aqueous ammonia (1 mole; conc.=approx 29%) in an Erlenmeyer flask. A stirbar is added, and the flask is stoppered. The flask is stirred at room temperature for three days. At this point the contents of the flask is distilled. At standard pressure, aceamide will distill over between 200-220°C. If a vacuum is used (highly recomended), pure acetamide distills at 158°C (100 torr), 136°C (40 torr), 120°C (20 torr), 105°C (10 torr), or 92°C (5 torr).
Acetamide is a white, crystalline substance substance that readily disolves in water. It has a mp of 81°C.
Procedure
20g dry acetamide is mixed with 54g Bromine in a 500ml flask. A solution of 20g
KOH in 200ml H2O is added dropwise with the flask resting in an ice bath. (Look
for a red-brown → yellow color change) Disolve 60g KOH in 100ml water, cool, and
add to a 1L RBF. Add the N-Bromo-acetamide dropwise to the flask with a thermometer
checking that the temp doesn't exceed 75°C. Once addition is complete, and when
the rxn mix begins cooling, maintain a temperature of 65°C on a water bath for 30
minutes. Set the flask up for distillation, in the receiving flask place 100ml
of dilute HCl (probably; calc. 2x mol's needed to form salt of a 60/40 MeAm/NH3 mix). Distill the MeAm+NH3 out of the flask and stop when the distillate coming
over is no longer alkaline (how to test that?). Evaporate the H2O out of the
HCl+distillate on a water bath (75°C). Dissolve the colorless residue in hot 100%
EtOH (It must be 200proof) NH4Cl will be insoluble. Filter off what should only
be a few grams of NH4Cl. Pour the EtOH into a beaker and cool. Later filter out
the Methylamine and dry it in a dessicator.
Reference:
Sudborough and James, Practical Organic Chemistry, Exp. #131, pp. 179-180 (1931)
[Organic Syntheses, Coll Vol 1, pp. 3-4]
In a 5 L flask is placed 3 kg (2860 mL, 50.0 moles) of glacial acetic acid and to this is added a weight of ammonium carbonate corresponding to 400g. (23.5 moles) of ammonia (Note 1). The flask is fitted with a one-hole stopper holding an efficient fractionating column 90 cm. long with condenser and receiver. An air condenser 150-200 cm. long may be employed. The mixture in the flask is heated to gentle boiling and the flame so regulated that the rate of distillation does not exceed 180 mL per hour. The distillation is continued in this way for eight to ten hours, until the temperature at the head of the column reaches 110°C. The distillate, which is a mixture of water and acetic acid, amounts to 1400-1500 mL The receiver is changed, the flame under the flask is gradually increased, and the distillation is continued at about the same rate until the temperature at the head of the column rises to 140°C. The distillate, which amounts to 500-700 mL, is largely acetic acid and may be used in the next run.
The contents of the flask are transferred to a 2 L flask for fractional distillation, having a column 40 50 cm. long, and distilled under atmospheric pressure, using an air condenser. The fraction boiling below 210°C, amounting to 250-300 mL, is collected separately. The material remaining in the flask is nearly pure acetamide and may all be distilled, 1150-1200g passing over at 210-216°C. By redistilling the fraction boiling below 210°C, the yield may be increased to 1200-1250g (87-90% of theory). The acetamide thus obtained is pure enough for most purposes, but if a purer product is desired it may be recrystallized from a mixture of benzene and ethyl acetate; 1 L of benzene and 300 mL of ethyl acetate are used for 1 kg of acetamide (Note 2). Colorless needles melting at 81°C are thus obtained (Note 3). The solvent and the acetamide it contains may be recovered by distillation.
Acetamide can be prepared by the rapid distillation of ammonium acetate2 by heating ammonium acetate in a sealed tube and distilling the product3 by treating acetic anhydride with ammonia4 by heating a mixture of ammonium chloride and sodium acetate to 240°C5 by the action of cold aqueous ammonia on ethyl acetate6 by boiling a mixture of glacial acetic acid and ammonium thiocyanate for four days7 by saturating glacial acetic acid with dry ammonia and then refluxing8 by distillation of ammonium acetate through a reflux condenser filled first with glacial acetic acid and then with aniline until the temperature of the mixture reaches 220°C9 by passing a stream of ammonia through heated acetic acid10 and from formamide and hydrogen at 200-500°C11.
The procedure described is based on the method of Noyes and Goebel12 in which equimolecular proportions of ammonium acetate and acetic acid are heated together, the acetic acid having been shown to accelerate both the dehydration of ammonium acetate and the hydrolysis of acetamide.