Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
 Pages:  1  2  
Author: Subject: Ethylamine Synthesis
Waffles SS
Fighter
*****




Posts: 968
Registered: 7-12-2009
Member Is Online


[*] posted on 13-2-2012 at 10:50


Someone know what pressure neede for reducing Acetonitrile to ethylamine(Raney nickel)?i think it should be below 10atm
View user's profile View All Posts By User
entropy51
Gone, but not forgotten
*****




Posts: 1612
Registered: 30-5-2009
Member Is Offline

Mood: Fissile

[*] posted on 13-2-2012 at 10:59


Quote: Originally posted by Waffles SS  
Someone know what pressure neede for reducing Acetonitrile to ethylamine(Raney nickel)?i think it should be below 10atm
If you have Raney Ni it might be possible to reduce it with NaBH4 and avoid a hydrogenation.
View user's profile View All Posts By User
Waffles SS
Fighter
*****




Posts: 968
Registered: 7-12-2009
Member Is Online


[*] posted on 13-2-2012 at 11:32


Thanks entropy but I have Roth autoclave and also i have access to hydrogen gas but now i dont have Sodium borohydride
I think reduction is possible at ~4atm
http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv3...
View user's profile View All Posts By User
S.C. Wack
bibliomaster
*****




Posts: 2345
Registered: 7-5-2004
Location: Cornworld, Central USA
Member Is Offline

Mood: Enhanced

[*] posted on 13-2-2012 at 15:51


IIRC Hofmann and Stoll used Raney at STP in an LSD article...this is well known to give a mixture, maybe a little more diethylamine.
There are some claims that this and that is more selective for one, for instance if you had NaBH4, Ni/B could be made instantly; it's been claimed to be more selective for ethylamine.

There are also condition hints around for the RX that are said to make it more selective for the primary amine.

PS: Got sodium? Good use here.
PPS: That's just for example, you know, maybe you have some not doing anything. Feel free to experiment. Urushibara? In situ?

[Edited on 14-2-2012 by S.C. Wack]




"You're going to be all right, kid...Everything's under control." Yossarian, to Snowden
View user's profile Visit user's homepage View All Posts By User
Waffles SS
Fighter
*****




Posts: 968
Registered: 7-12-2009
Member Is Online


[*] posted on 13-2-2012 at 22:02


This is my autoclave(right side)


Unfortunately i dont have a NaBH4 and LiAlH4
I tried Hofmann rearrangement but i was unsuccessful.I like to try another possible method.
I want to try Acetonitrile reduction method.I read some where that this reduction happen at 400k and at gas phase.

[Edited on 14-2-2012 by Waffles SS]
View user's profile View All Posts By User
Ephoton
National Hazard
****




Posts: 463
Registered: 21-7-2005
Member Is Offline

Mood: trying to figure out why I need a dark room retreat when I live in a forest of wattle.

[*] posted on 14-2-2012 at 16:11


I am often unsuccessfull on a first attempt of a synth that is new to me.

Trust me hofmann works and works very very well for low weight amides.

propionamide will turn easily too ethylamine and in very high yeilds with hofmann.

this is one of the routes that Bee's have been using to make methylamine for years it
is tried and tested and does not produce any dimethylamine :)

I believe that it was probably your amide that was at fault if you had problems with this reaction
as it is truly one of the easists reactions there is.

you just add the amide to the bleach at temps around 5 C and stir like mad.

after it all turns into a milk shake add caustic and heat till you hit 70 C

reaction should be over with in an hour or two.

If you havent come up with a way to collect your goods you will be breathing them
very hard to miss.

Nice autoclave by the way wish I had one like that.

how much did that cost you :)




e3500 console login: root
bash-2.05#

View user's profile View All Posts By User
Waffles SS
Fighter
*****




Posts: 968
Registered: 7-12-2009
Member Is Online


[*] posted on 15-2-2012 at 22:46


Dear Ephoton ,
I think my Propionamide is impure.i made it by heating ammonium propionate like orgsyn site method for making acetamide(Ammonium Sulfate + calcium calcium propionate)

I keeped temp at 0-5C but it seems the reaction goes run away
Did you try this method for making primary amine?

This is my lab autoclave, it cost 10000$(with full Accessories),i like my pilot autoclave(it made of Titanium/Tantalum)It has 100lit capacity


[Edited on 16-2-2012 by Waffles SS]
View user's profile View All Posts By User
Ephoton
National Hazard
****




Posts: 463
Registered: 21-7-2005
Member Is Offline

Mood: trying to figure out why I need a dark room retreat when I live in a forest of wattle.

[*] posted on 16-2-2012 at 06:28


I have never made the amide the way you have state but rather made the ammonium salt then heated till I got
amide distilling over :)

If you look at the wiki page on propionamide you will see it has a boiling point of 213C
http://en.wikipedia.org/wiki/Propionamide

If we look at this msds entry we can see that ammonium propionate has a melting point of 45C
http://unionbiotechnology.en.alibaba.com/product/252355078-2...

I was not making propionamide but other alphatic amides for solvent (formamide)

the synthesis should run the same though.


this is a great way to get the amide I think as you have a solid that will not boil anywere near the
brake down point needed to rearrange to amide and a very definative boiling point to check purity of
amide.

I have always gone from free acid with ammonia/amine gassed into it.

the orgsyn reaction you have linked too does not use calcium propionate but rather the free acid
it also does not use the sulfate of ammonia but rather the carbonate.
(that is if we consider acetic acid propionic for our purpouses)

I think what your trying to do is form calcium sulfate and ammonium propionate from the salts your using.

It may be better to use the compounds direct both ammonia and propionic acid.

It does work as can be seen by the methyamine synth and the luckart reaction posted on
rhodium.

well no wonder I dont have one of those wonderfull machines at that price :D

still very nice I can understand your wishing to use it to reduce acetonitrile.

It would seem from this post and this patent that you will need to dope your nickel cat or you will end up
with aldehyde or other reduction products of this kind.

Having said that all I have done is use a search engine I have not played with nickel cats as I can not get them.
http://www.sciencemadness.org/talk/viewthread.php?tid=17075
http://www.freepatentsonline.com/5777166.html

If you got a liquid distill from your mix at the right temp it should be propionamide I would think.

I can not think of anything else that would come from ammonium propionate that would boil at such a high
temp.

Xylene is a great recrystalisation solvent for amides. just add amide to boiling xylene till it will disolve no more.
and let cool.

you should get very very pure amide from this method I would think well from other amides I and others have
and the orgsyn article you linked to uses benzene and ethylacetate.

I have not worked with propionamide but the thought of ethylamine lithium reductions makes me wonder
why I never did (maby becouse I was never into benzylic alcohols of course ethylamine has many other uses)




[Edited on 17-2-2012 by Ephoton]




e3500 console login: root
bash-2.05#

View user's profile View All Posts By User
Waffles SS
Fighter
*****




Posts: 968
Registered: 7-12-2009
Member Is Online


[*] posted on 16-2-2012 at 09:13


Thanks dear Ephoton ,
I made my ammonium propionate by calcium propionate + ammonium sulfate and then i heated ammonium propionate for making propionamide.like orgsyn method for making acetamid(i used ammonium propionamide instead of ammonium acetate)
It seems something happening At 160-170. lot of smoke Appear and Yellow/Orrange liquid start to come over. i think this Yellow/Orange liquid is Impurities.i didnt Distill my final product again and i used it directly in Hofman reaction

Maybe I try another method for making Propionamide. i think This method is easier( i will make Propanoic acid by H2SO4 + Calcium propionate)

2 H3C-CH2-COONH4 + NH2CONH2 = 2 H3C-CH2-CONH2 + (NH4)2CO3

Also i found this:
Hydrogenation of Basic Nitriles with Raney Nickel
Wolfgang Huber
J. Am. Chem. Soc., 1944, 66 (6), pp 876–879
DOI: 10.1021/ja01234a009
Publication Date: June 1944
http://pubs.acs.org/doi/abs/10.1021/ja01234a009

[Edited on 16-2-2012 by Waffles SS]
View user's profile View All Posts By User
Ephoton
National Hazard
****




Posts: 463
Registered: 21-7-2005
Member Is Offline

Mood: trying to figure out why I need a dark room retreat when I live in a forest of wattle.

[*] posted on 16-2-2012 at 16:34


As I said I have no experiance with nickel cats.

Good luck though it would seem you have the equipment.

ye amides are normally white in color and this one should be solid at room temp this might explain why it was not working properly.

If you decide to try it again I would recrystalise the product after distillation from xylene.

I am not sure about ammonium propionate but with the urea hofmann even traces of some ions
will screw it up (hence the use of gelitin to capture and hold these ions)

This is not the case though for all amides when put through hofmann.




e3500 console login: root
bash-2.05#

View user's profile View All Posts By User
Waffles SS
Fighter
*****




Posts: 968
Registered: 7-12-2009
Member Is Online


[*] posted on 16-2-2012 at 21:58


Do you know solubility of Propionamide in xylen and another solvent?(I know its very soluble in water)
View user's profile View All Posts By User
mightywingman4
Harmless
*




Posts: 2
Registered: 19-2-2012
Member Is Offline

Mood: No Mood

[*] posted on 19-2-2012 at 23:05


Quote: Originally posted by Dr.Bob  
Quote: Originally posted by Arsole  

Could you Distill off the Ethylamine and use the differences in solubility between Diethylamine and Triethylamine to separate the two.


I don't think you could use water solubility to separate them, as once you add diethylamine to water, you create a new mixture, which would readily dissolve triethylamine. Remember solubilities are determined with single, pure compounds, and most impure chemicals are much more soluble, as well as the effect of adding a new chemical to the solvent changes its solvent properties, and almost always makes a better solvent. For example, many paint strippers are a mix of non-polar and polar solvents, as that will dissolve much faster and much more stuff than any one solvent would do. So purification of mixtures of liquids by solubility generally does not work well.

However, A decent still with even a moderate distillation column can separate liquids of different BPs quite well, if the distillation is done slowly and carefully controlled. I have distilled Freon isomers from each other which only had a 1-3 C difference in BP, using a 3' fractionating column, but for over 10C, it is not hard to distill compounds apart to a reasonable purity. Plus, if you want diethylamine, having a trace of triethylamine would generally not hurt, is it is mostly non-reactive. Same way, you could remove traces of DEA from TEA by reacting the DEA with a chemical that would form a new compound and then distill off the TEA. It would be a pain, but I have done such things before in a pinch.


What if you only had triethylamine? Would you somehow be able to reduce it down to diethylamine? What would it take if it's possible?
View user's profile View All Posts By User
weiming1998
International Hazard
*****




Posts: 616
Registered: 13-1-2012
Location: Western Australia
Member Is Offline

Mood: Amphoteric

[*] posted on 20-2-2012 at 05:02


I have no sources for this, but maybe the reaction between an amine/amide and ethanol will generate ethylamine? I have tried to isolate glucosamine from glucosamine HCl with ethanol as a solvent before. When I boiled the crushed glucosamine HCl pill with sodium hydroxide in the ethanol, a thick white vapour that smells somewhat like ammonia had begun to collect. Soon it ignited my container with a yellow flame. I extinguished the flame with a wet cloth, then filtered the liquid. More of this vapour collected and boiled out, even as I was filtering this. Soon the vapour stopped evolving, and I was left with a brown solution of what I thought was glucose.

Maybe you could give this a try with a distillation setup, with the end that receives the ethylamine cooled by some ice in a box around, but not in the receiving flask.
View user's profile View All Posts By User
S.C. Wack
bibliomaster
*****




Posts: 2345
Registered: 7-5-2004
Location: Cornworld, Central USA
Member Is Offline

Mood: Enhanced

[*] posted on 20-2-2012 at 15:49


Ehh...........I'd try distilling alanine and baryta first.



"You're going to be all right, kid...Everything's under control." Yossarian, to Snowden
View user's profile Visit user's homepage View All Posts By User
weiming1998
International Hazard
*****




Posts: 616
Registered: 13-1-2012
Location: Western Australia
Member Is Offline

Mood: Amphoteric

[*] posted on 21-2-2012 at 01:37


Quote: Originally posted by S.C. Wack  
Ehh...........I'd try distilling alanine and baryta first.


Are you sure that creates ethylamine and not a barium salt of this amino acid? Or some other decomposition product when heated?

[Edited on 21-2-2012 by weiming1998]
View user's profile View All Posts By User
mightywingman4
Harmless
*




Posts: 2
Registered: 19-2-2012
Member Is Offline

Mood: No Mood

[*] posted on 21-2-2012 at 15:43


I heard there was a way to do it with light...but can't really find the correct reference on the web. Can anybody direct me to a source? Of this or something similar?

...Or just tell me how if you know? =) Would be much appreciated, thanks!
View user's profile View All Posts By User
Waffles SS
Fighter
*****




Posts: 968
Registered: 7-12-2009
Member Is Online


[*] posted on 21-2-2012 at 20:53


Quote: Originally posted by weiming1998  
I have no sources for this, but maybe the reaction between an amine/amide and ethanol will generate ethylamine? I have tried to isolate glucosamine from glucosamine HCl with ethanol as a solvent before. When I boiled the crushed glucosamine HCl pill with sodium hydroxide in the ethanol, a thick white vapour that smells somewhat like ammonia had begun to collect. Soon it ignited my container with a yellow flame. I extinguished the flame with a wet cloth, then filtered the liquid. More of this vapour collected and boiled out, even as I was filtering this. Soon the vapour stopped evolving, and I was left with a brown solution of what I thought was glucose.

Maybe you could give this a try with a distillation setup, with the end that receives the ethylamine cooled by some ice in a box around, but not in the receiving flask.

I think That is Ammonia not Ethylamine

[Edited on 22-2-2012 by Waffles SS]
View user's profile View All Posts By User
Ephoton
National Hazard
****




Posts: 463
Registered: 21-7-2005
Member Is Offline

Mood: trying to figure out why I need a dark room retreat when I live in a forest of wattle.

[*] posted on 22-2-2012 at 05:34


ye not sure on the solubility and as it has a low melting point it would probably end up as the solvent that
disolves the xylene if you get what I mean.

but if you put enough in there and put it in the freezer it would crystalise out nicely.

no way your going to get ethylamine from ammonia and ethanol distillation.

another way would be to go through acetaldehyde oxime and reduce it but that would take
synthesis of both acetaldehyde and the oxime.

if you wished to go through ethanol maby forming ethylbromide first then reacting with ammonia might
be the go.

anhydrous conditions is needed for this reaction if my memory serves correctly.

the delepine reaction should work as well I think so you could use hexamine in stead of ammonia which
would have to be bubbled into an alcohol.

I think your talking about adding an amine onto an alkene mightywingman4.
http://www.devileye.net/catalog/winding_machine/light-cataly...

I have yet to hear of some one pull this off at home though it has been discussed in the past for synthesis
of other amines.

"18.2 moles of ammonia was charged into a reactor system consisting of a one-liter stainless steel reservoir, a quartz reactor for admitting the actinic light to the solution, and a circulating pump. External to the quartz reactor was an ultraviolet light source. Both reactor and light source were enclosed in a reflecting stainless steel cylinder. Ethylene was then charged into the system until the pressure reached 260 psig and 2.3 moles of ethylene were dissolved in the ammonia. Before the lamp was turned on, the solution was circulated for approximately one-half hour to ensure proper mixing and to cool the reactant mixture to 7.degree.-8.degree. C. No reaction was observed in this period. The circulating high pressure (autogenous) liquid reactant mixture was then exposed to ultraviolet lamps for the time periods given in Table 1. Analyses of the final mixture by gas chromatography are also shown in the Table. Conversations are given for ethylene, and yields are to mixed mono-, di- and tri-ethylamines. The high-energy xenon flash lamp of Table 1 discharges 25 joules over a 10 cm. path through a 1 mm. bore; the spectral output peaks at 3000 .ANG. and a large proportion of the radiation falls in the range of 1800-2200 .ANG.. "




e3500 console login: root
bash-2.05#

View user's profile View All Posts By User
weiming1998
International Hazard
*****




Posts: 616
Registered: 13-1-2012
Location: Western Australia
Member Is Offline

Mood: Amphoteric

[*] posted on 23-2-2012 at 03:34


Quote: Originally posted by Waffles SS  
Quote: Originally posted by weiming1998  
I have no sources for this, but maybe the reaction between an amine/amide and ethanol will generate ethylamine? I have tried to isolate glucosamine from glucosamine HCl with ethanol as a solvent before. When I boiled the crushed glucosamine HCl pill with sodium hydroxide in the ethanol, a thick white vapour that smells somewhat like ammonia had begun to collect. Soon it ignited my container with a yellow flame. I extinguished the flame with a wet cloth, then filtered the liquid. More of this vapour collected and boiled out, even as I was filtering this. Soon the vapour stopped evolving, and I was left with a brown solution of what I thought was glucose.

Maybe you could give this a try with a distillation setup, with the end that receives the ethylamine cooled by some ice in a box around, but not in the receiving flask.

I think That is Ammonia not Ethylamine

[Edited on 22-2-2012 by Waffles SS]


Probably not ammonia, because there is no water in the system. To have ammonia evolution, you need water and the only possible reaction that forms ammonia without water in this case is that the NaOH exchanges the OH- for the NH2- ion, which will make sodium amide, which will then react with ethanol to form ammonia and sodium ethioxide. But C2H5+ would be a much stronger acid than Na+, and the NH2 will be attracted to the stronger acid, forming ethylamine.
View user's profile View All Posts By User
Waffles SS
Fighter
*****




Posts: 968
Registered: 7-12-2009
Member Is Online


[*] posted on 23-2-2012 at 05:41


Your Ethanol was anhydrous?Did you try to condense it?
View user's profile View All Posts By User
weiming1998
International Hazard
*****




Posts: 616
Registered: 13-1-2012
Location: Western Australia
Member Is Offline

Mood: Amphoteric

[*] posted on 24-2-2012 at 00:50


I think I have made a mistake. I tried to test my methylated spirits for water by putting dry, white (with a hint of green) copper sulfate into the alcohol. after some swirling, it went green, so there are traces of water. I will try and completely eliminate the water, then repeat later.

I have repeated my experiment with anhydrous alcohol (the methylated spirits is treated with anhydrous copper sulfate thoroughly first. If it has water, it will be in very, very minute quantities that wouldn't contribute much. But still the same thick vapours and the same distinct smell of ammonia.

[Edited on 24-2-2012 by weiming1998]
View user's profile View All Posts By User
Waffles SS
Fighter
*****




Posts: 968
Registered: 7-12-2009
Member Is Online


[*] posted on 24-2-2012 at 10:47


I am doubtful! Ethylamine is little difference in smell than ammonia.

Today i found out: I did mistake and i didnt make ammonium propionate from ammonium sulfate + calcium propionate.
Yesterday i tried this reaction again and i became surprise.nothing happened after adding calcium propionate solution to ammonium sulfate solution,it was clear without sediment :o




[Edited on 24-2-2012 by Waffles SS]
View user's profile View All Posts By User
weiming1998
International Hazard
*****




Posts: 616
Registered: 13-1-2012
Location: Western Australia
Member Is Offline

Mood: Amphoteric

[*] posted on 25-2-2012 at 02:45


Quote: Originally posted by Waffles SS  
I am doubtful! Ethylamine is little difference in smell than ammonia.

Today i found out: I did mistake and i didnt make ammonium propionate from ammonium sulfate + calcium propionate.
Yesterday i tried this reaction again and i became surprise.nothing happened after adding calcium propionate solution to ammonium sulfate solution,it was clear without sediment :o




[Edited on 24-2-2012 by Waffles SS]


Exactly! The vapours smelled much the same as ammonia.
View user's profile View All Posts By User
cal
Hazard to Self
**




Posts: 88
Registered: 7-2-2012
Member Is Offline

Mood: No Mood

[*] posted on 27-2-2012 at 06:46
Google Heads


Quote: Originally posted by Waffles SS  

Quote:

Alcoholysis of sulfamic acid produces ammonium akyl sulfates. On page 629 of the attached article it discusses an example where methanol refluxed with sulfamic acid for several hours yields ammonium methyl sulfate. Ammonium methyl sulfate rearranges at high temperature to methylamine sulfate.

See ammonium.methyl.sulfate.pdf here
http://psychedelichosting.info/Ionium/Rhodium/pdf
or http://80.244.243.200/archive/rhodium/pdf/index.html

http://www.sciencemadness.org/talk/viewthread.php?tid=1261&a...


What about ammonium ethyl sulfate?it should produce ethyl amine sulfate. isnt it?

WELL SAID
View user's profile View All Posts By User
cal
Hazard to Self
**




Posts: 88
Registered: 7-2-2012
Member Is Offline

Mood: No Mood

[*] posted on 27-2-2012 at 08:56


Quote: Originally posted by Waffles SS  
@Ephoton,Yes Hofmann Rearrangement is really interesting


I think we can customize below route for Ethylamine .
This method for making ethylamine is easier than methylamine because ethylamine boil at ~16c( I have access to calcium propionate :D)
But i think ammonium propionate can easily be made from ammonium sulfate and calcium propionate.but i dont know what temp needed for making ammonium propionamide from ammonium propionate.
Quote:

Synthesis of Methylamine/Methylamine HCl via Hofmann Rearrangement
There are two approaches to producing an amine from an amide using the Hofmann rearrangement reaction. One way is to react the primary amide with an alkaline-halide solution (eg - Sodium Hydroxide and Bromine). The other method is to use an alkaline-hypohalite solution (eg - Sodium Hydroxide and Calcium Hypochlorite). The astute observer will notice that there is no chemical difference in the two processes. One produces the Hypohalite in situ, the other uses the Hypohalite itself. Substitution of various halogens/halides/hypohalites/hydroxides is acceptable, but I feel I have picked the best combination of maximal yield and ease of availability. Feel free to prove me wrong ;-). Also, at least one text specifies that Sodium Hypochlorite produces much higher yields than Sodium Hypobromite. This delicious vindication is expected since Chlorine is a more reactive halogen than Bromine. Now, we are going to use Calcium Hypochlorite, in the form of powdered pool shock, because concentrated Sodium Hypochlorite is a rare, unstable creature indeed. Our yield will not suffer in the slightest because of this.

The main example presented will be the alkaline-hypohalite method as it is the easiest to acquire the necessary chemicals. It is of interest to note that the alkaline-halide method is much easier to perform, processwise, in that it is more forgiving of sloppy technique.

The general theory behind the process is that the hypohalite will convert the amide to a haloamide. This then spontaneously changes to the isocyanate when heated and decomposes to the amine from the water present. In effect, all that happens is that a Carbonyl (CO) group is stripped off the starting amide to yield the corresponding amine. Yields pre-purification are around 80%, post-purification average around 65%. Certain uses of the resulting amine will not require purification, though, so it will be left up to you whether or not to perform those steps.

To make methylamine we start with Acetamide. The general, unbalanced reaction process is thus:

CH3CONH2 + Ca(OCl)2 ----> (CH3CONCl)2Ca++ + H2O
then
(CH3CONCl)2Ca++ + NaOH ----> CH3NH2 + Na2CO3
CAUTION Methylamine is a poisonous, noxious inflammable gas. It has a strong ammonia/rotting fish-like odor. It's not as bad as Chlorine gas, though, which can be produced if one is careless in the beginning!


You can scale these reactions up or down within reason. What is reasonable? I can't say, but I have done batches from .01 to 1 mole with no difficulty. The key problems in scaling this reaction have to do with heat gradients in the flask and inadequate stirring. Use your own judgement, keeping in mind that this is not an industrial process.

One reference to keep in mind (Thanks to J.W. Smith for sending this one) concerns the first step of the reaction.

Whitmore and Thorpe, J. of the Amer. Chemical Society, Vol 63, April 1941, p1118
"It was necessary to allow several hours for the formation of the N-chloroamide before heating to degradation temperature. With this modification it was possible to prepare methylamine...consistently in 78% yield."
In my experience, this is a true statement. Please remember to keep the reactants well iced, though. Now, to begin:
In a large mixing bowl which can contain a smaller stainless steel mixing bowl, prepare an ice bath with water and salt to bring the temperature down to -10C or so. Setup your glassware for simple distillation with magnetic stirring beforehand because certain steps need to be performed quickly. Use a vacuum adapter to connect to the receiver flask, and attach some rubber or polypropylene tubing to the vaccum nipple to connect to a bubbler setup (a funnel inverted in a beaker, or a plastic aquarium aerator tube). The distilling flask should be sitting in in a stainless steel bowl with nothing in it (you will add pre-heated oil to the bowl).

NOTE In order to make this as painless as possible, please observe the following recommendations: 1) Keep the mixing bowl temperature as close to 0C or less as possible; 2) Keep the Hypochlorite solution as it is being added as close to 0C or less as possible; 3) After half the Hypochlorite solution has been added, place a plastic bag with 50-100g ice/salt/water mix into the bowl to help keep temperatures low (use this instead of directly adding ice to the reactants, which adds a considerable volume of water making the process less volumetrically efficient); 4) Purchase an 8lb bag of ice ahead of time!


Next you will prepare three solutions.

10g of Acetamide in 20mL of distilled water.
16.4g of Calcium Hypochlorite (Pool shock) in 50mL of hot distilled water
24g of Sodium Hydroxide (Lye) in 40mL of cold distilled water
This last solution should be prepared slowly as it is quite exothermic. Set all three aside in a freezer. Now prepare the mixing apparatus which will be a stainless steel "mixing bowl" suspended in the ice/salt bath made earlier. We use a stainless steel bowl here so that heat transfer will be maximal, while preventing any corrosive interaction. A glass bowl will not be sufficient for larger scale preparations as it will not conduct heat fast enough to prevent the reactants from going over 10C (at which point the Haloamide will decompose and you'll have to start over). Take the Sodium Hydroxide solution out of the freezer once it is cool, but not cold.
After the bowl has been sitting in the ice bath for a few minutes, add the Acetamide solution. Stir well until the solution has cooled to -10C. Now, slowly add the Hypochlorite solution to the mixing bowl in bursts of no more than a couple mL while stirring vigorously. If you do this perfectly, there will be no fizzing or bubbling at all. This depends on how cold you keep the mixture, and how slowly you add the pool shock! Realistically, the considerable heat evolution of the reaction will make adding the last few mL a trying task! Keep an additional 50g of ice on hand to throw directly into the mixture if necessary. This solution may evolve Chlorine gas so you should obviously perform this step under a fume hood or outside). Keep stirring until it has calmed down and turned a turbid colorless to light green Let it sit for 2 hours, stirring occasionally and making sure that it never gets warmer than 5C.

After the 2 hours is up, add the Sodium Hydroxide solution quickly with stirring. The solution should immediately turn a chalky, milk white. That's because a lot of Sodium Carbonate just got generated. You no longer need be concerned over it's temperature, so you can leave the solution in this state overnight if perhaps the hours have passed by too quickly and you've suddenly realized it's 2:00am.

Preheat a water bath on the stove (or wherever) to about 80C and place the stainless steel mixing bowl in it. Once the temperature of the solution hits about 65C, take the bowl out and set aside while stirring all the while. This is where it rearranges, and the reaction is exothermic enough to sustain it's temperature nicely. If you find the temperature climbing past 80C, immerse the bowl into some cold water briefly. After about 15 minutes the temperature will start to fall, at which point you should transfer the whole mess to the distilling flask. Before you continue you need to choose whether you want to make the hydrochloride salt or the aqueous solution of Methylamine, though.

Heat the flask using an oil bath to 100C after adding this solution to effect gentle boiling which will drive off the Methylamine as a gas. In my experience, misbehavior is likely to occur at this point. One particular problem to watch out for is the sucking back of bubbler solution (be it plain water or 6N HCl) into the receiver flask. I don't know why the pressure in the distilling flask would go below atmospheric, and therefore cause this to happen, but it has several times with me. Needless to say, this results in a serious mess and botches the whole process (I have found a cure for this by using an automotive one-way vacuum valve, like a PCV).

Continue heating the flask contents until you have collected around 100mL of distillate in the receiver.

For the aqueous solution: Place 18mL of cool distilled water into your bubbler setup. The expected, not theoretical, yield of Methylamine from this amount of reactants is 7 grams. I have used a plastic aquarium aerator tube as the bubbler with excellent results. Sure beats using an inverted funnel.

For the HCl salt: Do exactly as above except use 6N Hydrochloric Acid. 6N HCl may be produced by diluting 60.4mL of "Muriatic Acid" to 100mL with distilled water. Evaporate the bubbler solution to dryness then add 15ml of water, 10mL 10% NaOH soln. and heat gently to a boil with constant motion until dense white fumes appear. This will remove the Ammonium Chloride. Remove from heat while stirring as it cools down. Pulverize the dry residue, then reflux with absolute Ethanol for several minutes. Filter the refluxed soln. on a heated Buchner or Hirsch funnel, then distill the alcohol off the filtrate until crystals just begin to form. Allow the soln. to cool naturally to room temperature, then cool further in an ice bath. Filter the solution on a chilled Buchner funnel with suction. The yield of Methylamine Hydrochloride should be around 55% of the theoretical.

To clean the white residue off of your glassware, dump some muriatic acid straight from the jug onto them and swirl.

References:

Journal of Chemical Education, v14, pg542
Organic Reactions volume 3
Vogels Elementary Practical Organic Chemistry, pg574



Do you know decompose temp of chloride salt of Ethylamine ?and solubility in acetone and EtOH?




[Edited on 21-1-2012 by Waffles SS]



Derivative Type: Hydrochloride
CAS Registry Number: 557-66-4
Molecular Formula: C2H7N.HCl
Molecular Weight: 81.55.
Percent Composition: C 29.46%, H 9.89%, N 17.18%, Cl 43.47%
Properties: Crystals from ethanol + water, mp 110°. d 1.22. Soluble in 0.4 part water; freely sol in alcohol; slightly sol in chloroform or acetone. Practically insol in ether. Keep well closed.
Melting point: mp 110°
Density: d 1.22
View user's profile View All Posts By User
ScienceSquirrel
International Hazard
Thread Pruned
13-3-2012 at 05:13
 Pages:  1  2  

  Go To Top