Author Topic: Catalytic hydrogenation of MDP2P/Nitromethane  (Read 8403 times)

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mottaman420

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Catalytic hydrogenation of MDP2P/Nitromethane
« on: April 03, 2002, 01:56:00 AM »
When doing a catalytic hydrogenation of MDP2P/Methylamine to MDMA can one use nitromethane as the methylamine source? Has anyone tried this? How would you go about doing this? What kind of yields can be expected from such an endevor? Should i have posted this in the newbee forum? 8)  Feel free to flame if i fcked up. But hey at least i try.

_.-==''SupaTokaBuDsMoka''==-._
'''''''GonnaGetHighTillIDie'''''''

Moriarty

  • Guest
I don't understand
« Reply #1 on: April 03, 2002, 03:34:00 AM »
Catalytic hydrogenation is a concept for saturation, generally double bonded carbons, olefins.  What could that possibly have to do with methylamine or nitromethane?  It would just seem to me like this idea would negate the methylamine from ever forming MDMA out of MDP2P.  Wouldn't you get 3,4-Methylenedioxyphenyl-2-propanol and unreacted methylamine?  I'm not trying to flame, I'm just curious.

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Rhodium

  • Guest
H2/cat fro reductive amination
« Reply #2 on: April 03, 2002, 07:15:00 PM »
Not true. See my page for examples of catalytic hydrogenation as a means for reductive amination.

I do not know of any trials with this system using nitromethane as the amine source. However, KrZ has done it in a two-step reaction, where he first reduced nitromethane to methylamine in a bomb, then added ketone and reduced. If it is not on my page, then it must be in the archives here.


Moriarty

  • Guest
Using Rh/C
« Reply #3 on: April 04, 2002, 12:43:00 AM »
"A solution of 49.8 g (0.3 mole) of 3,4-dimethoxybenzaldehyde in 150 ml of 95% ethyl alcohol containing 20 ml of 29% aqueous ammonia (0.33 mole) and 25 g (0.3 mole) of ammonium acetate was hydrogenated at room temperature and 3 atm in the presence of 9.0 g of 5% rhodium on carbon.  Uptake of hydrogen was complete in about 3 hr.  After removal of catalyst, the filtrate and washings were concentrated and the residue distilled.  A 64% yield of 3,4-dimethoxybenzylamine, bp 118-120 (1.5 mm), was obtained."  Catalytic Hydrogenation in Organic Synthesis, Morris Freifelder, p. 92, 93, 1978.

I only mention this because this particular synth recognized the superiority of Rh/C over that of Pd/C, getting 64% with Rh/C and 55% with Pd/C.  Unknown if this would be true for all ketone and aldehyde hydrogenations.  I believe Pd/C of preferred due to fact that the addition of Rhodium on a carbon support is said to be dangerous.  Also, most catalytic hydrogenations I've read involved extreme reaction environments, like several atmospheres of pressure.  Any thoughts on different catalysts?

Yields I have read about for the reduction of non-aromatic nitro groups have been bad and, as it would seem, less favorable than aldehydes and ketones and taking longer periods of time.  I believe that this might mean the use of Nitromethane would be a bad idea, allowing MDP2P to form stable products before nitromethane had even begun a conversion.  My knowlegde here is very little, so not much emphasis should be placed on this assumption.  However, NO2 groups were reduced to NH2 in all the catalytic hydrogenation reductions mentioned in pages 31-36 of the above mentioned reference.

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mottaman420

  • Guest
I was considering something else
« Reply #4 on: April 04, 2002, 09:03:00 AM »
In my dream (literally) I considered using 150 ml ketone with 120 ml nitromethane and 110 ml Methanol and 1 grams Adam's Catalyst.  :P

_.-==''SupaTokaBuDsMoka''==-._
'''''''GonnaGetHighTillIDie'''''''

Ritter

  • Guest
catalytic hydrogenation
« Reply #5 on: April 04, 2002, 03:59:00 PM »
Mottoman:

What kind of yields did you "theoretically" get from that quoted rxn?  Its very easy to specifically reduce  CH3NO2 in the presence of ketone without reducing the carbonyl if catalyst loading is kept on the low side, temp is kept at room temp or less and pressure is not allowed to go above 25PSI.  Different inorganic salts can be added to the rxn. to modify the catalyst to make it more selective towards the imine rather than the ketone.  An example is Fe2SO4 or sodium acetate.  These modifiers don't turn the catalyst into a specific targeting majic bullet, they simply slow  the attack on carbonyls.  However, there are modifiers available which cause the catalyst to develop an extremely high affinity for nitro and imine groups, virtually leaving carbonyls untouched.  KrZ posted the patent for these unique catalysts and if memory serves correctly, they are composed of simple ordinary Pd/C or Pt/C treated with DMSO and/or hydrazine. (

http://gb.espacenet.com

)

Using standard Adams catalyst as you state in the reaction will work somewhat, however if you are just throwing everything into the bomb and hydrogenating, I know you never yielded more than 50g product (thats a generous educated guess) using 1gram PtO2.  The problem is  that such a small amount of catalyst will become poisoned fairly rapidly.  When the MeNO2/ketone mixture is pressurized w/ H2, the majority of the 2 mols of nitromethane will rapidly reduce  to methylamine.  As the methylamine forms,  it will start to condense with the ketone presenting yet another mole of reducible material (Imine).  One gram of PtO2 will  stop working after 1-1.5 mols of substrate is reduced due to poisoning.  A way around this is to use more PtO2, however you risk reducing the ketone to the propanol with more catalyst.

Yields will be MUCH higher if an ethanolic solution of MeNO2/EtOH is reduced first and  liquids are decanted off into another Parr bottle.  Ketone is SLOWLY added to the bottle of methylamine and an additional gram of PtO2 is added.  The imine reduction is carried out at about 50PSI and takes about 3 hours at room temp.   The yield will be very high- in the %80 range.

mottaman420

  • Guest
Literally
« Reply #6 on: April 05, 2002, 04:44:00 AM »
In my post when i said "in my dream (literally)" i really meant in my dream. I have never tried such a thing but was wandering if it could work. In an experiment posted by Labtop he used the following formula and their are many similar to it:
1800 ml MDP2P
1200 ml Methanol
1200 ml (1080g) anhydrous liquid MeNH2 (bp -6°C!)
24 g Platinum(IV)oxide (Adam's Catalyst)

I was just wandering if you could just substitute nitromethane in the methylmine's place so that this type of reaction would be available to those who can't get anyhydrous liquid MeNH2 so easily. Assuming that this worked, I was wandering if you could expect similair yields to the ~90% that was supposedly gotten in these type of reactions by various people. If it were indeed true that such a high yield could be gotten that way, than it would seem that many peoples lives would have been much improved. All I'm saying is that if you can substitute it in the Almagation of Al/Hg than why not in the catalytic blah blah blah. I guess i was just hoping that i would have inspired someone to go out and try and hopefully develop a new way for making drugs. I think it would be really great if my contribution to the world in cohesion with someone else would be to make a new way of cooking drugs.

_.-==''SupaTokaBuDsMoka''==-._
'''''''GonnaGetHighTillIDie'''''''

Antoncho

  • Guest
l-PAC
« Reply #7 on: April 05, 2002, 01:55:00 PM »
Cat. hydrogenation of l-PAC and methylamine in ether w/Reney Ni catalyst was the original way for producing ephedrine.

I believe, in another patent they use aq. solutions (???)


Antoncho

Sunlight

  • Guest
Water
« Reply #8 on: April 05, 2002, 06:52:00 PM »
Reduction  of nitromethane produces water, and someone told that the catalytic hydrogenation of MDP2P with emthylamine didn't work with aqueous methylamine, I think it's in Rhodium's page. Anyway youd make a smalll test, small workup to see how it works.

Ritter

  • Guest
aq. methylamine
« Reply #9 on: April 06, 2002, 03:01:00 AM »
Kitty,

Just last night I read an article by Freifelder in which he hydrogenated a mixture of 30%aq. methylamine (.5mols),  P2P(.5mol) and enough ethanol to make the soln homogenous (I think about 150ml).  1.5grams PtO2 was added and hydrogenated at 50psi to yield 90% methamphetamine.  This proves water has no appreciable effect on formation of methyl imines.  I spent the past half hour looking for that article for you, I can't believe I cant find it.  If you really want the citation, let me know and I'll tear my house apart till I find it.  The details I reported in this post are a perfect duplicate of the reference though.  Freifelder is the master of catalytic hydrogenation of phenylacetones.  Over the years I have probably seen about 50 different reductive aminations of phenylacetone published by his group.

Not to mention SWIM gets 85% yields of MDE using 70%aq. ethylamine, so water definetely isn't a problem.

terbium

  • Guest
Aqueous methylamine ala Freifelder.
« Reply #10 on: April 06, 2002, 11:44:00 PM »

Post 182995 (missing)

(terbium: "Re: Silica gel mesh size conversion(s)...", Chemistry Discourse)

mottaman420

  • Guest
What should be done?
« Reply #11 on: April 07, 2002, 03:58:00 AM »
So what would the ideal ratios of the reactents be in such a reaction. What is the least amount of Adam's catalyst that could be used without suffering to much on the yields?
Also how do you mesure volumes in a canister full of gas (ie if you had to add liquid methylamine to a hydrogentaion than how would you measure out the amount your putting in if trying to avoid freezing temperatures?)

_.-==''SupaTokaBuDsMoka''==-._
'''''''GonnaGetHighTillIDie'''''''

flipper

  • Guest
catalyst
« Reply #12 on: April 22, 2002, 04:29:00 PM »
Ritter wrote:


.  KrZ posted the patent for these unique catalysts and if memory serves correctly, they are composed of simple ordinary Pd/C or Pt/C treated with DMSO and/or hydrazine.




See this Thread

Post 299856

(flipper: "What SWIM wanna make with it", Chemicals & Equipment) and

Post 300160

(flipper: "another question", Chemicals & Equipment)
and

Post 174784

(KrZ: "Sulfided Platinum Catalysts", Novel Discourse)
and

Post 174918

(KrZ: "Re: Sulfided Platinum Catalysts", Novel Discourse)


US patent 3941717 Alias DE 2150220 and GB 1397584
US patent 5498585

PtO2 who needs it. Too expensive. The catalyst described in patent 5498585 is propably better and cheaper. 



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terbium

  • Guest
Strange conclusion.
« Reply #13 on: April 22, 2002, 09:20:00 PM »
PtO2 who needs it. Too expensive. The catalyst described in patent 5498585 is propably better and cheaper.
Isn't that patent describing a platinum on carbon catalyst? So how is that significantly cheaper, or better? 

Organikum

  • Guest
methylamine HCl
« Reply #14 on: April 22, 2002, 10:09:00 PM »


the british patent

GB 365 535

describes the reductive amination of L-PAC which should be similar to P2P with methylamine HCl in alcoholic and aqueous solution. Nickel is the catalyst used, yields don´t know, the speak of "good yields" whatever thus maybe.
But, no methylamine gas ever needed, the product of ammmoniumchloride and formaldehyde or hexamine can be used as is. Wouldn´t that be a step in the right direction? No more sibirean family gasing? ;)


Ah baikal, but the smell....
ORGY

flipper

  • Guest
Well
« Reply #15 on: April 22, 2002, 10:54:00 PM »

Isn't that patent describing a platinum on carbon catalyst? So how is that significantly cheaper, or better? 




I assume it is. Let's compare. 100 grams of the catalyst in the patent where i'm talking about contains 3 grams of Platinum. Molar mass of PtO2 weights 227.078.  85.91% of That weight is Platinum. Molar weight of Platinum is 195.08 g/mol And that is 85,91% of the weight of the PtO2, So of 100 grams of PtO2 85.91% is Platinum. What is Cheaper A catalyst containing 3 grams of Platinum or a catalyst containing 85,91 grams of Platinum. That alot of money. I think the price of Platinum these days is something around 150 Dollars/gram.
Then the patent's tell that the yields are better the selectivity is improved and that the reaction time is reduced.
God I only hear good things about this catalyst. I also wanna say that SWIM have not yet xperience with it but he is very impatient to trie it.


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terbium

  • Guest
Specious and irelevant
« Reply #16 on: April 23, 2002, 02:19:00 AM »
How much of a precious metal based catalyst to use in a process is determined by the precious metal content. If a procedure calls for 20 grams of 5% platinum on carbon then instead one might use 10 grams of 10% platinum on carbon or 1.2 grams of platinum oxide.


Then the patent's tell that the yields are better the selectivity is improved and that the reaction time is reduced.
God I only hear good things about this catalyst.

And you believe everything that you read in a patent. Well, golly gee, you are a trusting soul!

Organikum

  • Guest
surprise Mr Terbium and flipper!
« Reply #17 on: April 23, 2002, 06:20:00 AM »
surprisingly the link Mr Terbium provided answers this little dispute. This proofs that Terbium links are always worth a read and for everybody too. ;)


and hydrogenated at room temperature and 3 atm of pressure with 1.4 g of platinum oxide



and then


It is possible to substitue 20 g of 5% platinum on carbon.




I am no artist of handheld calculators like flipper, but it is obvious that his way to calculate is not perfectly thought to the end :) .

The relation is 1,4g Pt oxide to 20g Pt/c 5%.

Mr flipper please do the calculation of netto Pt amounts,
but sorry Mr Terbium I see already now that the needed netto amount of Pt is less with Pt/C than with Adams catalyst.
I read the patents on sulphidized catalysts and I agree this should be worth a try but mainly because of reusability. The needed amount of Pt should equal usual Pt/C. Also I had a look at Matthey´s and Adams catalyst seems not to be considered the best choice nowadays, just because of not providing enough surface. But perhaps this is a question of personal taste as I met a chemist lately who told me he would never use anything else then Pt on asbestos. Aha I thought.

flipper the results please!


now I will do some ziatype in my photostudio to relax
ORGY


terbium

  • Guest
Only advantage may be selectivity.
« Reply #18 on: April 23, 2002, 05:07:00 PM »
but sorry Mr Terbium I see already now that the needed netto amount of Pt is less with Pt/C than with Adams catalyst.
I didn't say otherwise. What I said was that flipper's reasoning - that 1 gram of 3% platinum on carbon catalyst is equivalent to 1 gram of Adams' catalysts - is incorrect.
 
I read the patents on sulphidized catalysts and I agree this should be worth a try but mainly because of reusability.
Other Pt/C catalysts can also be reused. I thought that the "advantage" of the sulphided catalysts was supposed to be selectivity. If they truly show selectivity for imine over ketone then it might be possible to use them to good advantage for the production of products such as MDA. On the other hand, for products such as MDMA, where catalytic hydrogenation using PtO2 or plain Pt/C already give yields approaching 100%, there would seem to be little or no advantage.

Also I had a look at Matthey´s and Adams catalyst seems not to be considered the best choice nowadays, just because of not providing enough surface.
Again, I don't believe that I said otherwise. If one is running an industrial process, producing low value product, where cost of catalyst is paramount, then Pt/C will probably provide some advantage due to reducued Pt requirement. You may find, for example, that 0.8 gram of platinum as 10% Pt/C will do the job of 1 gram of platinum as PtO2.

flipper

  • Guest
Terbium sir my lord This is what you sad on ...
« Reply #19 on: April 23, 2002, 06:44:00 PM »
Terbium sir my lord

This is what you sad on February 23 of 2001

Post 174951

(terbium: "Re: Sulfided Platinum Catalysts", Novel Discourse)


Lots of insanely high yielding reductive aminations.

But you can get the same yields from plain PtO or Pt/C without bothering to sulfide the catalyst.

And this is what the lord of Hydrogen Krz answered.

Post 174965

(KrZ: "Re: Sulfided Platinum Catalysts", Novel Discourse)


Not like this you can't.  Look at LabTops PtO4 writeup.  He describes usage of a very expensive quantity of the catalyst. You could use close to the same weight of 3% sulfided catalyst and get equal if not better results.  You also must control the pressure to help reduction of imines in preference to ketones, which can cost time.  The sulfided catalysts (1) Require less catalyst per quantity of ketone (2) Provide better yields (admittedly only slightly since the current techniques are already high yielding) and (3) Are poisoned much more slowly and therefore remain active longer.  If you are going to be using a platinum catalyst for this sort of procedure, you might as well go through with such a simple procedure to improve it so much.

Also, this extreme selectivity finally opens up the possibility of a one-pot nitro->amine, amine+ketone->imine->amine catalytic hydrogenation reaction.  Previously, side reactions while the amine was forming would have made this impossible, but now it is well in reach! And not a intensely nonscaleable Al/Hg type reaction, just dumped all your goodies together and blast it.


Too make a point:



He describes usage of a very expensive quantity of the catalyst. You could use close to the same weight of 3% sulfided catalyst and get equal if not better results.




If one can Hydrogenate with a Sulfided 3% Pt/C catalyst and get better yields and use almost the same quantity of catalyst as when you're using PtO2. Well I think my choice is quickly maked. I bet you that A 3% Pt/C catalyst is alot cheaper then PtO2.


flipper the results please!




SWIM likes to give them but SWIM has some money problems so he first have to work a little bit. I mean a real job with a salary. Maybe I will be rich sometime and maybe thanks too this catalyst.  8)


You've gotta love me.