Sciencemadness Discussion Board

do it yourself hydrogenation

zmth - 31-1-2011 at 21:27

I read the following off the web search.

"Kitchen Hydrogenation

is thought of as the reaction you can't do because you don't have the gear. bullshit, thats what Parr and buchi want you to think. I'm going to fill you in on a couple apparatus that get the job done and anyone can do. The two applications I will address are the saturation of the double bond in morphoid opiates and the reduction of the schiff base double bond.

alkene saturation can be done at low H2 pressure so no tank is needed, balloon pressure is tons and depending on the amount of catalyst used can go anywhere from a couple hours to overnight. Go to ebay and buy a little pneumatic paint shaker for twenty up to a hundred dollars, you'll need a compressor too. This is going to give you the violent agitation that a reaction like this needs for efficiency, if you try to stir it don't come crying to me when you grandkids are getting married and your damn hydrogenation still isn't done. Your vessel? A green beer bottle, green breaks down the light that breaks down the codeine. Into this clean bottle goes either cod. free base or any salt and methanol to dissolve, sometimes you may put a few drops of water in with the salt form to dissolve it. ethyl acetate is also an excellent solvent for this but requires ph altering. Now throw in you catalyst, for this there is no substitute for pd on barium sulfate 5%. Now make your hydrogent by putting a couple inches of hcl or sulfuric in a bottle, dropping in some iron filings and fitting a balloon over the bottle to collect the gas, you may want a neutralizing tube as hcl fumes are liberated. This goes over your beer bottle, its clamped into the paint shaker and you light that shit up, shake it as fast as it will go, you want it frothing in there. Run it until your balloon stops shrinking. try to minimize head space or else its difficult to see the balloon shrink as not much hydrogen is used. Thats it, an atmospheric hydrogenation apparatus and it WILL work if you give it the agitation and time.

for high pressure. go to the hardware store and find a garden sprayer that you pump up to pressurize, they are good to over 50psi. Get a massive party balloon and fill it with hydrogen then fit it over the plunger so it covers the intake. you'll need to pump the plunger while its inside the balloon, you'll get it, since you've epoxied a gauge into the top of the sprayer you know when to stop pressurizing. Now fit the sprayer into the shaker and let er have it. It is that simple, you don't need a five thousand dollar system that does a lousy 500ml.
of course a bottle of proper hydrogen can't be ignored as a very important feature to the system."

Does anyone know what is he talking about - mainly his slang words hydrogent etc. Another question he says "...Run it until your balloon stops shrinking. .." should he have said stops expanding. I'm confused as to what is the division of subject as to making the hydrogen and then using the hydrogen or is it all done in the same pot?

Another thought of mine is say using a one pot application is with HCl diluted with water to a proper amount and with carbon as the anode and aluminum as the cathode just apply
a voltage source of around 2 volts . I have done this type of electrolysis for other purposes other than for the production of hydrogen and reduction of the double bond and know that the anode is the problem - even stainless steel gets quickly dissolved as the anode but using it as the cathode it is much slower at dissolving and other than purchasing special anode materials carbon as the anode is about best.

Now anyway say for the purpose of saturating the double bond in codeine it is done in an acid environment and using say aluminum as the cathode it will get somewhat dissolved and should form aluminum chloride and there should be two ways hydrogen is produced - without any voltage applied the Cl from the HCl forms aluminum chloride and hydrogen is liberated and also should get hydrogen from the electrolysis of water - i forgot whether the oxygen collects at the anode or cathode ? and hydrogen at the other. Ofcourse the codeine or whatever will also be in the same single vessel tightly sealed. Also have heard that aluminum chloride is used as a catalyst so perhaps should not need expensive palladium etc. catalysts since I am in no hurry and could even wait up to a few days even and i could easily make an electric shaker ?

Does anyone know whether this has been done and why or why not it will work and/or whether or not to forget the electrolysis part- will the formation of oxygen hurt anything other than if it was to get too hot may get an explosion?
I am speaking of a small scale operation like with a few milli moles of codeine and total Hcl and water less than 300ml.

bbartlog - 1-2-2011 at 06:42

Quote:
Run it until your balloon stops shrinking


The balloon has been transferred from the generator to the bottle.
Quote:
there should be two ways hydrogen is produced


Yes. But you make it sound like that's a good thing, which it isn't. I see no reason to perform electrolysis in this case, the aluminum would produce plenty of hydrogen; however it might also reduce some of your substrate. There is a reason that the hydrogen gets produced in a separate step and I wouldn't try to do this in one pot until you have success doing it in two steps.
Quote:
have heard that aluminum chloride is used as a catalyst so perhaps should not need expensive palladium etc. catalysts since I am in no hurry and could even wait up to a few days


Yes, all those professional chemists who use palladium when doing hydrogenation are actually functionally retarded. Aluminum chloride (anhydrous, which you wouldn't have here) catalyzes some reactions, but you are making it sound like catalysis is some sort of generic thing rather than being applicable to specific kinds of reaction. It won't work as a hydrogenation catalyst.
If you want something other than palladium (which I can understand, it is indeed expensive) then look up Urushibara catalysts.

Quote:
should not need expensive palladium etc. catalysts since I am in no hurry and could even wait up to a few days


With catalysis the reaction might take a few hours. Without catalysis I expect you are looking at geological timescales. Mere patience is not going to help you.
Overall the instructions you copied are disappointing... at the very least I was hoping this DIY cook had prepared his own catalyst, but no. The use of a paint shaker I guess is interesting assuming you have an air compressor (I do but I think most people don't).

ScienceSquirrel - 1-2-2011 at 07:01

I would guess that if you used aluminium and sodium hydroxide solution or similar to generate and fill a balloon with hydrogen and then transfered the balloon to a beer bottle hydrogenator :D and used one of the catalysts in the patent below with magnetic stirring it would work.
Codeine seems to hydrogenate quite easily at low temperatures and pressures.

http://www.freepatentsonline.com/6887999.html

Dr.Bob - 2-2-2011 at 20:48

Chemists use balloons of hydrogen all of the time for simple reactions, like reducing nitro groups or double bonds, removing benzyl protecting groups, etc. But you will need a catalyst of some sort, best are palladium or platinum on carbon black, 5 or 10%, WET with 50% water (this keeps the catalyst from catching fire too easily in air.) This turns out to be a vanishingly small amount of Pd which can do a lot if you are patient.

Interestingly you can actually find some other chemicals that contain Pd as an impurity, which can be catalytically active. Scientists claimed that you could do some cross coupling reactions without Pd or Pt and it turned out that their carbonate salts had 0.01% Pd in them. So there might be a way to use other metals with Pd contaminants.

But just a small balloon of H2 can do a lot of hydrogenation. It is a bit hazardous, but not bad as long as you remove air from your reactions before adding hydrogen. Nitrogen works well, but many other gases would work.

Bob

zmth - 3-2-2011 at 21:54

Ok thanks for the info. - I assume when you say run it till the balloon stops shrinking means that is the 2nd step where the hydrogen is being used and not produced?

- but i don't see where the first quoted article i wrote ever transferred the balloon. Anyway i would assume the balloon will not get hydrogen at more than 20psi ?
Assuming atmospheric pressure is 14.7psi. I guess that is psia or pounds per sq in abosolute. Now i remember they have two scales of psig and psia. NOt sure what the
measurement is but i mean like reading say 20psi on a usual auto tire gauge so assuming it's at most going to be 20psi - less than two atmospheres and probably closer to one then one could just hold ones finger over it to transfer it from one bottle to the other or what is a better way? What are these contaminants specifically that contain enough platinum or palladium as impurities to work as catalysts. I did assume that different catalysts are for different reactions and think i heard to use a metal from group IV or V metals ? Would ramey nickel work at all?

peach - 4-2-2011 at 20:16

It's worth remembering that a catalyst isn't used up in a reaction. Meaning, you can recover and reuse it.

Palladium isn't insanely expensive, and you probably won't be using a whole lot of it either.

I was just having a read about Hydromorphone. I could have used some of that a few weeks ago. Everyone has been coughing like crazy since Christmas. I was drinking ephedrine syrup whilst putting up Christmas decorations, and then unable to get to sleep.

[Edited on 5-2-2011 by peach]

zmth - 5-2-2011 at 08:37

yes thanks for the reply and i kind of thought that also but the problem is how difficult and practical and time consuming it is to go about recovering it knowing one is not going to recover it all but how much % for time and effort spent. Also what other metals less expensive can be used. I would think that to increase the surface area to volume ratio that any of them should be in as small grain powder form as possible. What about titanium which i already have or even lead?

bquirky - 5-2-2011 at 08:58

I really have no idea at all. but will some nickel powder serve as as a catalysist perhaps at a slightly higher temp ?

vulture - 5-2-2011 at 09:40

Quote:

This is going to give you the violent agitation that a reaction like this needs for efficiency, if you try to stir it don't come crying to me when you grandkids are getting married and your damn hydrogenation still isn't done.


Erm, we (that is an acadamic lab) perform hydrogenations with H2 balloons, magnetic stirring and Pd catalysis all the time. Works in a few hours or overnight.

A very important thing is to remove all oxygen prior to adding the H2! Failing to do this when using a catalyst will cause explosions at some point!

peach - 5-2-2011 at 12:27

I have also seen people running the wacker oxidation (palladium salt) using plastic bottles, with the agitation being provided by simply shaking the bottle by hand. It runs at 50psi with O2 from a cylinder. Running it higher actually seems to encourage side product production for some substrates. Numerous people have done this and I've not seen a single person mentioning the bottles popping, due to them having a significantly higher burst rating.

Pressure is added by drilling a hole in the cap of the bottle and inserting a tyre valve from the inside, which well blocks the hole given the tough rubber surface it has. The valve is a lot fatter at it's base than at the top, so it's not coming back through the hole any time soon.

With regards to nickel, if you have a read of the Raney's nickel Wiki, you'll see that is essentially microporous nickel sponge.

The pores are made by creating a nickel / aluminium alloy, then then dissolving the aluminium out with a strong base.



[Edited on 5-2-2011 by peach]

starman - 5-2-2011 at 16:11

Pardon my ignorance.What is the purpose of reducing double bonds in codeine?

peach - 5-2-2011 at 16:28

I believe it could potentially have something to do with hydrocodone - a stronger form of codeine.

smuv - 5-2-2011 at 18:11

Reduction of a styryl group is a snap with Pd/c at room temp. However, amines are good poisons of most hydrogenation catalysts (including Pd/C) therefore it is a good idea even if you have the substrate as a salt, to run the hydrogenation with a few percent added acid. So i would recommend running the reduction in something like 5% conc HCl/95% MeOH (assuming you are using pd/c).

All solvents should be extremely pure (and the HCl) as well. Also, the substrate should likewise be very pure. The key to getting consistently good results with catalytic hydrogenations, is ensuring that your reaction is free from any catalyst poisons. Literally, just traces of certain compounds will bring a reduction to a standstill. For this reason, I aqua regia my whole aparatus (including stirbar) before running any hydrogenations. Maybe it may sound excessive, but, I get consistent results.

Also, 'double-bag' the balloons with 1 inside of the other; this does a good job preventing loss of hydrogen, and buy good quality thick party balloons. Also you must use good quality vacuum grease, and make sure that NO solvent ever touches the joint, even a little spatter from being stirred.


[Edited on 2-6-2011 by smuv]

wxyz - 6-2-2011 at 20:21

Quote: Originally posted by smuv  
Reduction of a styryl group is a snap with Pd/c at room temp. However, amines are good poisons of most hydrogenation catalysts (including Pd/C) ...

[Edited on 2-6-2011 by smuv]


I am wondering how that squares these abstracts that use Pd on carbon to reduce compounds containing an amine group:

Dobke et al., Amines. Brit Pat 509,661, July 19, 1939; C.A. 34: 3761(6) (1940).
Amines were produced from esters of 1-aryl-2-amino-1-propanols and their N-substitution products by
catalytic hydrogenation in a nonaqueous medium, preferably under pressure. Among the examples given, 1-phenyl-2-methylamino- 1-propanol is stirred into alcohol and hydrogenated by aid of a palladium black carrier catalyst at about 50° and 4 atm. to give the theoretical yield of 1-phenyl-2-aminopropane.

Temmler-Werke, Amines. Fr Pat 844,227, July 20, 1939; C.A. 34: 7297(1) (1940).
A method for the preparation of amines from 1-aryl-2-aminopropanol esters or their N-substituted derivatives
by catalytic hydrogenation consists of effecting the hydrogenation in a nonaqueous medium and preferably
under pressure. The yield is quantitative. Among examples, racemic 1-phenyl-2-methylaminopropane, b.p.20mm. 92-94°, is obtained by dissolving 4 parts of the sulfuric ester of racemic pseudoephedrine in 200 parts of alcohol, subjecting the solution to a hydrogenating operation under a pressure of 3 atm. at 50°, in the presence of a catalyst composed of palladium and carbon, eliminating the catalyst by filtration after the absorption of the calculated amount of hydrogen, concentrating the filtrate, treating it with diluted H2SO4 and precipitating the amine by means of an alkali.


Also, I am really curious what you know about which compounds are most likely to poison Pd catalysts. I already know to avoid HS, but what are the others?

smuv - 6-2-2011 at 21:04

If you are really serious about this, got to the nearest university library, there will be at least a half dozen books about catalytic hydrogenation, they usually have at least a chapter about catalyst poisons (and will have at least another chapter about reduction of conjugated double bonds). For palladium catalysts (what I have most of my experience with), poisons are generally nucleophiles: thiols, amines, nitrogenous heterocycles (pyridine, quinoline) are usually strong inhibitors. Weak nucleophiles like chloride are slight inhibitors, but for practical purposes I ignore them.

I am not saying, all amines will stop a hydrogenation in its tracks...but certain amines and definitely certain nitrogenous heteroaromatics will. Thats not to say, you can't do chemistry on amines, you just have to understand that generally, the reaction times would be less, the catalyst loading lower, and the conditions milder without such functionality (or where applicable, doing the hydrogenation on the salt, or in an acidic medium).

I will not say any more, because this has already, come to the point, of me simply spoonfeeding to your how to make a drug. The only reason I am really doing it, is I really like catalytic hydrogenations, and I think it is a technique that more and more is being overlooked in modern organic synthesis. So I will just point you in the right direction, and be on my way. Pretty much everything I know about this subject (aside from first hand experience):

Catalytic hydrogenation; techniques and applications in organic synthesis
by Augustine, Robert L., 1932- Published 1965

Catalytic hydrogenation in organic synthesis : procedures and commentary /
by Freifelder, Morris, 1907- Published 1978

Catalytic hydrogenation in organic syntheses /
by Rylander, Paul Nels, 1920- Published 1979

Practical catalytic hydrogenation; techniques and applications.
by Freifelder, Morris, 1907- Published 1971

wxyz - 7-2-2011 at 11:48

Thanks a lot for the clarification. When I get conflicting information from different sources I usually learn something when I prod further to sort it out. What you say would explain why some of the catalytic reductions of compounds with amines groups use a very high ratio of Pd catalyst to starting material.

I know it is hard to tell from a post whether the poster is a meth-head trying to milk information from experts without doing any work on their own, or a person (like myself) who is actually very interested in chemistry and for some reason drawn to topics that society disapproves of and/or are dangerous and/or fun.

In any case I really appreciate the references and will undoubtedly have one of those books you mentioned in my hands soon :)

zmth - 10-2-2011 at 17:51

Quote: Originally posted by Dr.Bob  
Chemists use all amount of Pd which can do a lot if you are patient.

Interestingly you can actually find some other chemicals that contain Pd as an impurity, which can be catalytically active. Scientists claimed that you could do some cross coupling reactions without Pd or Pt and it turned out that their carbonate salts had 0.01% Pd in them. So there might be a way to use other metals with Pd contaminants.

Bob


What about an old catalytic converter which I have? From what i understand the honeycomb(actually small square cylinders rather than hexagonal structure) like structure is ceramic substrate with Palladium etc. Do you know anyone who has used them as catalysts with success?

Nicodem - 12-8-2013 at 08:00

An example of the transfer hydrogenation using limonene* has been reported at Synthetic Pages:
Transfer hydrogenation of benzpthalide with limonene/palladium on carbon; 2-(2-phenylethyl) benzoic acid (DOI: 10.1039/SP535)

* Limonene become widely available as a paint thinner and typical non-polar solvent for general public use. You can buy it at any larger shop where they sell paints and related items. It is also a good starting material for synthesis (for example, for the synthesis of para-cymene).

Platinum Black Catalyst

cal - 13-8-2013 at 03:02

The catalyst can be made by placing two pieces of platinum under distilled water with 120 volts applied. The ends should be brought together until almost touching and a arc is produced. The material that falls to the bottom is your platinum black catalyst. This is used with only 35 lbs pressure for a hydrogenation reaction with excellent results. Time was about 1 hour in the reaction I performed some 25 years ago.

[Edited on 13-8-2013 by cal]