Why do you suggest that? It adds to alkenes quickly and is an excellent leaving group why should a catalyst be needed?
Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #160 on: March 11, 2011, 01:56:32 PM »
Topic: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole... (Read 2846 times)
Sedit
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akcom
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #161 on: March 11, 2011, 08:18:50 PM »
There are a number of reasons, the first that comes to mind is the high electron density of the alkene and the nitrogen atom. Also the reaction is very slightly exothermic but very entropically unfavorable. There is a good review on the topic by Muller and Hultzsch published in Chemical Review. Just search for hydroamination. They go into the challenges and the procedures.
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #162 on: March 12, 2011, 05:51:34 AM »
Well post the paper or a link, else im left to believe your at a misunderstanding as the information does not register with the lost knowledge in my head correctly.
Im left to assume your speaking of,
Hydroamination: direct addition of amines to alkenes and alkynes.
http://www.mendeley.com/research/hydroamination-direct-addition-of-amines-to-alkenes-and-alkynes/
Chemical Reviews (2008)
Volume: 108, Issue: 9, Publisher: American Chemical Society, Pages: 3795-3892
PubMed ID: 18729420
IF so I wish someone to provide that paper. Everything you just spoke of in the last post appears completely off,IE the opposite of reality of the situation. This is the reason for the excellent leaving group effects of sulfuric additions to alkenes. SN2 is very likely. To likely in most cases cause H2O to add and rearrangment to the 1 position occures rather quickly as it appears its more stable under strong acidic conditions then the desired alcohol.
Im left to assume your speaking of,
Hydroamination: direct addition of amines to alkenes and alkynes.
http://www.mendeley.com/research/hydroamination-direct-addition-of-amines-to-alkenes-and-alkynes/
Chemical Reviews (2008)
Volume: 108, Issue: 9, Publisher: American Chemical Society, Pages: 3795-3892
PubMed ID: 18729420
IF so I wish someone to provide that paper. Everything you just spoke of in the last post appears completely off,IE the opposite of reality of the situation. This is the reason for the excellent leaving group effects of sulfuric additions to alkenes. SN2 is very likely. To likely in most cases cause H2O to add and rearrangment to the 1 position occures rather quickly as it appears its more stable under strong acidic conditions then the desired alcohol.
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #163 on: March 12, 2011, 03:06:00 PM »
If it's such as facile transformation then I'm sure you'll find plenty of literature references performing the reaction just as you said. Until then I'm going to believe the guys with the PhD's.
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #164 on: March 12, 2011, 05:02:40 PM »
Here's the Hydroamination Review if anyone wants it.
Hydroamination - Direct Addition of Amines to Alkenes and Alkynes.pdf
(3772.69 kB - downloaded 15 times.)xxxxx
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #165 on: March 12, 2011, 08:39:52 PM »
I had a number of issues producing the methylamine for the amination, in particular very bad yield, mostly getting NH4Cl from the Hexamine/HCl solution.
I decide to use Ammonia for the first attempt just to remove the extra variables. I placed the 99.5% IPA in the freezer at approx -20c overnight. I then made up a saturated solution of NaOH in 250ml dH2O. I decided to use NH4NO3 to generate the NH3 as I had like 1kg on hand. Anyways I setup the apparatus like shown and slowly started to add the the NaOH to the 208grams AN with stirring. The gas was bubbled through the suckback generator into the 250grams IPA. But the problem was there was no bubbles! There was only bubbles when I was actually dripping in the NaOH. The minute I would stop dripping, the bubbling would stop.
Anyways after finishing adding the NaOH I weighed the IPA, no increase in mass what so ever! Any idea what i'm doing wrong. There was no smell of ammonia unless I opened the glassware. I have a feeling the endothermic reaction when the AN was disolved cooled the solution and allowed alot of the ammonia to disolve and not bubble out.
I can't really heat it either to bubble out the ammonia because it would bring a lot of water vapor with it? Any ideas what I could do, just use NH4Cl?
Thanks for your help already everyone!
I decide to use Ammonia for the first attempt just to remove the extra variables. I placed the 99.5% IPA in the freezer at approx -20c overnight. I then made up a saturated solution of NaOH in 250ml dH2O. I decided to use NH4NO3 to generate the NH3 as I had like 1kg on hand. Anyways I setup the apparatus like shown and slowly started to add the the NaOH to the 208grams AN with stirring. The gas was bubbled through the suckback generator into the 250grams IPA. But the problem was there was no bubbles! There was only bubbles when I was actually dripping in the NaOH. The minute I would stop dripping, the bubbling would stop.
Anyways after finishing adding the NaOH I weighed the IPA, no increase in mass what so ever! Any idea what i'm doing wrong. There was no smell of ammonia unless I opened the glassware. I have a feeling the endothermic reaction when the AN was disolved cooled the solution and allowed alot of the ammonia to disolve and not bubble out.
I can't really heat it either to bubble out the ammonia because it would bring a lot of water vapor with it? Any ideas what I could do, just use NH4Cl?
Thanks for your help already everyone!
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #166 on: March 12, 2011, 08:49:00 PM »
Did you used any liquid in a "suckback generator"!?
If you used water or anything acid there is your problem,
either that or leak in the apparatus.
Next time dissolve that AN in hot water and cool it down before use.
(make supersaturated solution)
If you used water or anything acid there is your problem,
either that or leak in the apparatus.
Next time dissolve that AN in hot water and cool it down before use.
(make supersaturated solution)
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #167 on: March 12, 2011, 09:04:36 PM »
Test the pH of the IPA by adding it to be a bit of water or something. When I have dissolved ammonia in certain liquids - it is dissolved at the same rate at which it is produced and no bubbles appear to form...
How did you test the mass of the IPA/Ammonia solution? What is the chance you lost a certain mass of the IPA from various transfers, or did the volume of it change at all?
Perhaps you may be better off heating urea to produce the ammonia, as it produces dry ammonia, and gets rid of the variable of it possibly dissolving in the solution that it formed in...because you are only heating the dry pellets.
Urea can be obtained in certain instant cold packs, might want to take a trip to the store and check that out?
How did you test the mass of the IPA/Ammonia solution? What is the chance you lost a certain mass of the IPA from various transfers, or did the volume of it change at all?
Perhaps you may be better off heating urea to produce the ammonia, as it produces dry ammonia, and gets rid of the variable of it possibly dissolving in the solution that it formed in...because you are only heating the dry pellets.
Urea can be obtained in certain instant cold packs, might want to take a trip to the store and check that out?
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #168 on: March 12, 2011, 09:37:33 PM »
Actualy best possible method is to get high concentration household ammonia
free from parfumes and other crap and titrate it with NaOH or other strong base solution.
Household ammonia is cheap abroad(USA,EU...).
free from parfumes and other crap and titrate it with NaOH or other strong base solution.
Household ammonia is cheap abroad(USA,EU...).
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #169 on: March 12, 2011, 10:36:28 PM »
How would that work?
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #170 on: March 12, 2011, 10:58:24 PM »
What Sedit!?
(Damn,where my post/edit on urea went?!)
It's very simple.
If you put NaOH or NaOH solution into NH3 solution you get NH3 gas,right?!
Urea+CaO+heat gives of dry NH3 gas.
(Damn,where my post/edit on urea went?!)
It's very simple.
If you put NaOH or NaOH solution into NH3 solution you get NH3 gas,right?!
Urea+CaO+heat gives of dry NH3 gas.
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #171 on: March 12, 2011, 11:12:23 PM »
Quote
Urea+CaO+heat gives of dry NH3 gas.
Interesting...
Perhaps mixing dry IPA with dry urea and excess CaO would be good? The urea would dissolve in the IPA, the CaO would react with the urea to produce ammonia, and react with any water present or formed, leaving you with ammonia in IPA, and producing Calcium Cyanate, CaO, and Ca(OH)2. Neither the calcium cyanate or hydroxide are soluble in IPA, from what I can tell... though I do not have any good references for this - so perhaps I will check in CRC in a bit.
That would be a nice way to do it, assuming you can deal with decanting off the ammonia alcohol from the fine white particles of calcium hydroxide/cyanate. However in alcohol solutions, those don't seem to stay suspended nearly as bad as in water solutions.
Assuming it all works, as I have not tried it, this would probably be the easiest method to go about it.
Sorry for the off-topic post.
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #172 on: March 12, 2011, 11:13:49 PM »
2 things you might be doing wrong
1: sounds like a leak
2: did you use glass wool or any type of gas dispersion mecchanism at the end of the tubing?
if not it would bubble out and you would capture very little in the alcohol.
btw that's exactly what happens as soon as you drip the base onto the nh4cl it bubbles instanly and stops so this is normal
1: sounds like a leak
2: did you use glass wool or any type of gas dispersion mecchanism at the end of the tubing?
if not it would bubble out and you would capture very little in the alcohol.
btw that's exactly what happens as soon as you drip the base onto the nh4cl it bubbles instanly and stops so this is normal
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #173 on: March 13, 2011, 12:43:32 AM »
Problem is that he said:"no increase in mass what so ever".
Either he gassed it only a little,IPA wasn't cold enough,he had a leak
or he had faulty method of weighting.
Vesp,problem with that idea is that reaction needs fair amount of heat
to get NH3 and solubility of NH3 in hot IPA is probably shitty.
I am not even sure if IPA has higher b.p. than temperature needed of that reaction!
Maybe mixing IPA,CaO and urea and distilling might do the trick!
Jon will say we are overcomplicating things but it's just fun to invent
new ways of doing the same thing.
Either he gassed it only a little,IPA wasn't cold enough,he had a leak
or he had faulty method of weighting.
Vesp,problem with that idea is that reaction needs fair amount of heat
to get NH3 and solubility of NH3 in hot IPA is probably shitty.
I am not even sure if IPA has higher b.p. than temperature needed of that reaction!
Maybe mixing IPA,CaO and urea and distilling might do the trick!
Jon will say we are overcomplicating things but it's just fun to invent
new ways of doing the same thing.
Wizard X
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #174 on: March 13, 2011, 12:59:09 AM »
Thermal decomposition of urea gives biuret, isocyanic acid and ammonia.
2 NH2CONH2 => H2NCONHCONH2 (biuret) + NH3 (ammonia)
NH2CONH2 => HNCO (isocyanic acid) + NH3
2 NH2CONH2 => H2NCONHCONH2 (biuret) + NH3 (ammonia)
NH2CONH2 => HNCO (isocyanic acid) + NH3
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #175 on: March 13, 2011, 01:40:22 AM »
Depending on the temperature and presence of other "average" reactants (H2O,O2...)
everything from those compounds to NOx,CO2 and N2 can
be produced by the thermal decomposition of the urea,but yes,those are the main products.
everything from those compounds to NOx,CO2 and N2 can
be produced by the thermal decomposition of the urea,but yes,those are the main products.
Vesp
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #176 on: March 13, 2011, 01:46:40 AM »
Have you guys ever decomposed urea? You don't see any white smoke form at all - which would happen if HNCO and NH3 were produced at any significant amount - as upon cooling they would form together again as urea... just as NH4Cl goes to NH3 and HCl than back again... -- correct?
This reaction to my knowledge produces cyanuric acid and ammonia as the two main products and in good yield
http://en.wikipedia.org/wiki/Cyanuric_acid#Properties_and_synthesis
When have done it, I put it in an oil that can withstand the temperature - something like olive oil/corn oil works - this allows for the urea to form into a more globular like shape, and as the ammonia bubbles form float out of the oil - sometimes taking a bit of the urea with it, which goes to the top and falls back down. At a certain point, the urea blob solidifies, and stops releasing ammonia.
while dry urea with CaO might require a decent amount of heat - do you think that having the urea dissolved in the alcohol and the CaO would need heat? I haven't done it, and I realize calcium oxide is not very reactive - but it seems to me like it would happen at a semi-decent rate. Perhaps it should be mixed, and left to stir at room temperature for a day... We can both agree it wouldn't happen super fast... but at least at the same rate calcium hydroxide forms from calcium oxide...
After all - if it were in dry alcohol, wouldn't it form alkoxides that would than be soluble and happy to react with the urea? Not super fast.. but in a day or so at least.
I would try this out as I think it would be very good and likely to work, but I have been mostly an armchair chemist lately and don't even have CaO or dry alcohol..
This reaction to my knowledge produces cyanuric acid and ammonia as the two main products and in good yield
http://en.wikipedia.org/wiki/Cyanuric_acid#Properties_and_synthesis
When have done it, I put it in an oil that can withstand the temperature - something like olive oil/corn oil works - this allows for the urea to form into a more globular like shape, and as the ammonia bubbles form float out of the oil - sometimes taking a bit of the urea with it, which goes to the top and falls back down. At a certain point, the urea blob solidifies, and stops releasing ammonia.
Problem is that he said:"no increase in mass what so ever".
Either he gassed it only a little,IPA wasn't cold enough,he had a leak
or he had faulty method of weighting.
Vesp,problem with that idea is that reaction needs fair amount of heat
to get NH3 and solubility of NH3 in hot IPA is probably shitty.
I am not even sure if IPA has higher b.p. than temperature needed of that reaction!
Maybe mixing IPA,CaO and urea and distilling might do the trick!
Jon will say we are overcomplicating things but it's just fun to invent
new ways of doing the same thing.
while dry urea with CaO might require a decent amount of heat - do you think that having the urea dissolved in the alcohol and the CaO would need heat? I haven't done it, and I realize calcium oxide is not very reactive - but it seems to me like it would happen at a semi-decent rate. Perhaps it should be mixed, and left to stir at room temperature for a day... We can both agree it wouldn't happen super fast... but at least at the same rate calcium hydroxide forms from calcium oxide...
After all - if it were in dry alcohol, wouldn't it form alkoxides that would than be soluble and happy to react with the urea? Not super fast.. but in a day or so at least.
I would try this out as I think it would be very good and likely to work, but I have been mostly an armchair chemist lately and don't even have CaO or dry alcohol..
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #177 on: March 13, 2011, 02:06:36 AM »
I decide to use Ammonia for the first attempt just to remove the extra variables. I placed the 99.5% IPA in the freezer at approx -20c overnight. I then made up a saturated solution of NaOH in 250ml dH2O. I decided to use NH4NO3 to generate the NH3 as I had like 1kg on hand. Anyways I setup the apparatus like shown and slowly started to add the the NaOH to the 208grams AN with stirring. The gas was bubbled through the suckback generator into the 250grams IPA. But the problem was there was no bubbles! There was only bubbles when I was actually dripping in the NaOH. The minute I would stop dripping, the bubbling would stop.
Swim wouldn't recommend adding the NaOH as a saturated solution as water holds a LOT of NH3 so the less water involved the better. Just use a container with some give (HDPE gas can lol) and add the both dry, must be done quickly may need a very small amount of water to start but after that it makes it's own. System should be able to handle a bit of pressure but nothing major. Pass the gas through a cooling/drying chamber before it goes through the IPA (Swim would
) and swim guarantees it'll bubble lots and the IPA will stick to more as the NH3 is already a bit cold. Just swim's 2ยขOerlikon
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #178 on: March 13, 2011, 02:45:22 AM »
We don't use SWIM here. It's agains the forum rules,it's logically pointless and self-insulting!
And no,that is not good advice at all! Harming actually!
Water can't hold allmost ANY NH3 when strong base like NaOH is present in same solution.
Not adding water is also pointless and harming since hydrolysis of NaOH produces A LOT
of heat and "water that it makes on it's own" will become steam,ruining everything if
you don't have CaO or CaCl2 tube to catch it,which is not good since every known good
desicant catches NH3 too.
Making concentrated solution of both ammonia salt and NaOH (separately of course!)
and cooling it prior mixing/use is tested and confirmed to work great!
And no,that is not good advice at all! Harming actually!
Water can't hold allmost ANY NH3 when strong base like NaOH is present in same solution.
Not adding water is also pointless and harming since hydrolysis of NaOH produces A LOT
of heat and "water that it makes on it's own" will become steam,ruining everything if
you don't have CaO or CaCl2 tube to catch it,which is not good since every known good
desicant catches NH3 too.
Making concentrated solution of both ammonia salt and NaOH (separately of course!)
and cooling it prior mixing/use is tested and confirmed to work great!
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Re: Yeee Haaah!! Jon's method DOES TOO work!! Bromosafrole...
« Reply #179 on: March 13, 2011, 03:04:21 AM »
What Sedit!?
(Damn,where my post/edit on urea went?!)
It's very simple.
If you put NaOH or NaOH solution into NH3 solution you get NH3 gas,right?!
Oh im sorry, I thought you said Titrate....
Yes sure you can do that... in theory, Ever try it?
Its a huge waste of NaOH and time. One would be so much better to drip a NH3 solution onto a drying agent like MgSO4 by the ton but even that sucks.
Better to stick to the chemical means. I tryed it all when I was working with Li[NH3]4 complex and I always came back to Ammonia Nitrate/NaOH for Ammonia production. Atlest im left with Sodium Nitrate. The most effective way, that I never tried mind you, I feel would be to drip a saturated solution of NaOH onto dry Nitrate. Pass this thru a drying tube/bottle to absorb all the water and feed it into NaCl/Ice chilled alcohol. The reason for the drip instead of a direct mixture of the two dry substances is because the dry mixing leads to a runaway when conditions become right then rapidly drop off in Ammonia production where as dripping the NaOH solution would cause a steady constant supply of NH3 to be feed into solution.