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ChemHack:

I've had pretty shitty yields trying to make Acetamide at home. The amountsused in the reaction below were experimentally derived so your milage mayvery with the uality o! starting materials. "atHead provided themotivation !or this experiment and I desparately seek his or anyone'sadvice on how to improve it.

#aterials:Aua Ammonium $low grade% &(gallon)*odak +lacial Acetic Acid,arge pot o! cool water $- uart or larger is good)+lass graduated cylinder/istilling apparatus0 glass mayonaise 1ars,ong stem !unnel $improvised via short !unnel w(tubing)

2tep 3ne: Ammonia Acetate

#easure 40ml Ammonium and pour into 1ar 5-. 6ut the 1ar in the !ree7er tochill. #easure 8ml +lacial Acetic Acid9 submurge entire glass graduatedcylinder in large pot o! cool water. or better stability9 make sure no airbubbles are trapped under the base o! the cylinder.

6lace !unnel into graduated cylinder so that the end extends well below thelevel o! the Acetic Acid. 6our Aua Ammonium into !unnel9 the !irst !ewdrops will react very vigorously and may spit Ammonium back out o! the!unnel so slow at !irst or wear goggles. ;xecpt !or the !irst little bit9the Ammonia can be added very uickly this way. Considerable heat isevolved but the water bath e!!ectivly cools the cylinder.

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2et up your rig !or !ractional distillation with a water cooled condenser.The temperature will rise as you heat the solution9 it will begin boilingin the neighborhood o! -C but the temperature will uickly rise understrong heating until it gets to --C. It will stick at --C !or a while as

Acetic Acid comes over. 2oon9 the temperature begins to rise again and thesmell9 which until this point was getting better9 will begin to get worse.Clear watery distillate will come over all the way up to 0C. I don't knowwhat it is but it smells pretty nasty. Third party noses have described itas the smell o! ?rotting ammonia? and ?rotting !ood with ammonia.? I thinkit smells like my urine a!ter a night in the co!!ee house drinking 1avaa!ter 1ava and smoking cigarettes.

"eplace the collection !lask when it gets to 0C and collect everythingbetween 0 and 00@. It is still a clear liuid and there is no doubt thatthere is some o! that smelly stu!! in there with it. 2topper the !lask andset it aside to cool down. hen it cools down somewhere below C it will!orm white crystals.

I! you 1ust heat it to 0C and keep everything that is le!t it will still

crystali7e but it seems to melt at a lower temperature and never be uitedry. Actually9 you can usually stop heating at -@C and it will crystali7eat room temperature but it will melt in your hand. The #2/2 !or Acetamidesays that it melts at -C.

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AC;TA#I/; CH8C30H4 DE CH8C3H0 F H03 2ubmitted by +. H. C3,;#A and A. #. A,BA"A/3. Checked by H. T. C,A"*; and ;. ". TAG,3".>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

-. 6rocedure

In a @>l. !lask is placed 8 kg. $0 cc.9 @. moles) o! glacialacetic acid and to this is added a weight o! ammonium carbonatecorresponding to 4g. $08.@ moles) o! ammonia $ote -). The !lask is!itted with a one>hole stopper holding an e!!icient !ractionating column cm. long with condenser and receiver. An air condenser -@>0 cm. longmay be employed. The mixture in the !lask is heated to gentle boiling andthe !lame so regulated that the rate o! distillation does not exceed -cc. per hour. The distillation is continued in this way !or eight to tenhours9 until the temperature at the head o! the column reaches --J. Thedistillate9 which is a mixture o! water and acetic acid9 amounts to-4>-@ cc. The receiver is changed9 the !lame under the !lask is

gradually increased9 and the distillation is continued at about the samerate until the temperature at the head o! the column rises to -4J. Thedistillate9 which amounts to @>K cc.9 is largely acetic acid and may beused in the next run.

The contents o! the !lask are trans!erred to a 0>l. !lask !or!ractional distillation9 having a column 4 @ cm. long9 and distilledunder atmospheric pressure9 using an air condenser. The !raction boilingbelow 0-J9 amounting to 0@>8 cc.9 is collected separately. The materialremaining in the !lask is nearly pure acetamide and may all be distilled9

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--@>-0 g. passing over at 0->0-J. -0@ g. $K> per cent o!the theoretical amount). The acetamide thus obtained is pure enough !ormost purposes9 but i! a purer product is desired it may be recrystalli7ed!rom a mixture o! ben7ene and ethyl acetateL - -. o! ben7ene and 8 cc. o!ethyl acetate are used !or - kg o! acetamide $ote 0). Colorless needlesmelting at -J are thus obtained $ote 8). The solvent and the acetamide itcontains may be recovered by distillation.

0. otes

-. Ammonium carbonate o! commerce is o!ten extremely impure9 and caremust be taken to obtain a representative sample !or the determination o!the ammonia content by titration with standard acid. The ammonium carbonateused in this preparation contained 0K.0 per cent o! ammonia9 and -4K g.was used in each run.

0. Crystalli7ation o! acetamide9 by solution in hot methyl alcohol $.cc. per g.) and dilution with ether $>- cc. per g.)9 has been recommendedas the best method o! puri!ication$-).

8. As acetamide is somewhat hygroscopic9 it cannot be exposed to theair unless precautions are taken to have the air dry.

8. #ethods o! 6reparation

Acetamide can be prepared by the rapid distillation o! ammonium acetate$0) by heating ammonium acetate in a sealed tube and distilling the product$8) by treating acetic anhydride with ammonia $4) by heating a mixture o!ammonium chloride and sodium acetate to 04J $@) by the action o! coldaueous ammonia on ethyl acetate $) by boiling a mixture o! glacial aceticacid and ammonium thiocyanate !or !our days $K) by saturating glacial

acetic acid with dry ammonia and then re!luxing $8) by distillation o!ammonium acetate through a re!lux condenser ! illed !irst with glacialacetic acid and then with aniline until the temperature o! the mixturereaches 00J $) by passing a stream o! ammonia through heated acetic acid$-) and !rom !ormamide and hydrogen at 0>@J $--).

The procedure described is based on the method o! oyes and +oebel $-0)in which euimolecular proportions o! ammonium acetate and acetic acid areheated together9 the acetic acid having been shown to accelerate both thedehydration o! ammonium acetate and the hydrolysis o! acetamide.

- agner9 =. Chem. ;ducation K9 --8@ $-8). 0 *undig9 Ann. -@9 0KK $-@).

8 Ho!mann9

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@ $-80)O. -0 oyes and +oebel =. Am. Chem. 2oc. 449 00 $-00)L "osano!!9 +uliek9 and ,arkin9 ibid. 889 Ki $---): Hitch and +ilbert. ibid. 8@. -K $--8).>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

6osted to the Hive -0>K> by /rone 5840

Acetamide is a use!ul compound. hen reacted with bleach9 it makesmethylamine gas. 2o you may say to yoursel!: ?/ambQ How do I get me some o!that%?. Aside !rom purchasing it9 its incredibly easy to makeQ Here's how:

44.@@ g $.@ moles) o! ethyl acetate is combined at room temperature with@ grams o! concentrated aueous ammonia $- moleL conc.Dapprox 0R) in an;rlenmeyer !lask. A stirbar is added9 and the !lask is stoppered. The !laskis stirred at room temperature !or three days. At this point the contentso! the !lask is distilled. At standard pressure9 aceamide will distill overbetween 0>00SC. I! a vacuum is used $highly recomended)9 pure acetamidedistills at -@SC $- torr)9 -8SC $4 torr)9 -0SC $0 torr)9 -@SC

$- torr)9 or 0SC $@ torr).

Acetamide is a white9 crystalline substance substance that readily disolvesin water. It has a melting point o! -SC.

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6ractical 3rganic Chemistry9 2udborough and =ames9 -8-9 p-K>-9 ;xp. 5-8-

0g dry acetamide is mixed with @4g brown>Eyellow color change) /isolve g *3H in -ml water9 cool9 andadd to a -l "