Sciencemadness Discussion Board - Catalytic hydrogenation - preparation of hydrogen in situ

Catalytic hydrogenation - preparation of hydrogen in situ

goldberg - 28-7-2018 at 05:40

I tried to search for this topic but failed, if i missed similar thread sorry for that.
Generally in hydrogenation reactions there is pressure vessel filled with compound to be hydrogenated and catalyst, then external hydrogen is added.

I'm curious if it would be possible to use hydrogen generated in situ?
Let's say i have open flask with dissolved compound (let's assume that everything happens in aqueous medium) and catalyst (let's say raney or urushibara nickel).
Then add metal like zinc or alumina and acid or base to digest it.
Assuming that compound to be hydrogenated will not react with given acid or base would it make sense?

There is classical way of reducing nitro compounds with Zn or Fe and HCl.
The only similar thing that i have found is strange looking procedure of preparing amphetamine (that i am NOT intrested in in any way) found on rhodium archive. This procedure tells that it uses urushibara nickel but procedure for preparation of this 'catalyst' looks very different than proper preparation of urushibara nickel. Like mix NiCl2 and hydrochloric acid then add aluminium foil. This article has no references so i do not count it as realiable resource of information.

I am intrested in this way becouse i would avoid complex apparatus for handling hydrogen under pressure. Moreover i hope that hydrogen in statu nascendi will be more reactive.

Has anybody experience with this topic? Does my reasoning make sense?

Chemi Pharma - 28-7-2018 at 06:06

See this topic about nitrocompounds reduction with many reagents couple:

http://www.sciencemadness.org/talk/viewthread.php?tid=84372&...

and this one about generation of nascent hydrogen from borohydrides and nickel salts or nickel raney, using nickel boride generated in situ as a hydrogenating source agent:

http://www.sciencemadness.org/talk/viewthread.php?tid=80555&...

and a sucessful experience about this last kind of hydrogenation in the sequence of the thread:

http://www.sciencemadness.org/talk/viewthread.php?tid=80555&...

[Edited on 28-7-2018 by Chemi Pharma]

alking - 28-7-2018 at 19:27

Yes, that is very common. The metal hydrides are the most common commercially but generally more difficult to obtain for home chemists. You can use various combinations of metals and acids for a transfer hydrogenation, amalgums, or if you get something like Pd or Pt on carbon you can keep reusing it via catalytic transfer hydrogenation. Do some research on the group you're trying to reduce and you should come across various methods, some work better than others, some are not strong enough/too strong, etc.

goldberg - 30-7-2018 at 07:23

Thanks for links i am reading them.
Unfortunately i have no access to metal hydrides and making them myself looks extremely labour intensive. Like lithium and hydrogen and high temperature. Making elaborate apparatus does not look feasible. Or maybe i am not aware of some route.

Second i'm curious about using freshly prepared hydrogen. One thing is that hydrogen bottles are dangerous and expensive. Second is that freshly prepared hydrogen is much more active that one that will stand in bottle for a while(at least i was taught this). So maybe it would make sense to use freshly prepared hydrogen instead of one from bottle?

BTW. can You recommend me some source of Pd and/or Pt for preparation of catalyst? This metals are very expensive and i did not noticed any places where i can buy them in pure form other than even more expensive jewellery.

Chemi Pharma - 30-7-2018 at 08:16

Oh Man, in what country do you live that you don't have acess to metal hydrides?

Pd/C or Pt/C is very, very expensive and difficult to recover from the reaction. At maximum you will spend a lot of money and will use the catalyst just twice. They are generally sold as one gram everywhere you watch for it. Just to you think about.

Urushibara nickel it's not feasible cause the low yields you achieve and cause the difficult work up to make it. Any mistake you did, you will stay with a unuseful reagent to hydrogenate anything.

Aluminium amalgam is extremely toxic and dificult to take off all the mercury dissolved in the work up.

The modern chemistry, applied by the pharmaceutical industry uses borohydrides to do professional hydrogenations. More over, hydrogenations done with hydrogen reactors under pressure it's a surpassed thing. Nowadays are used LiALH4, NaBH4 and metal couple, like nickel, cooper, cobalt or other exotic reagents, DIBAL, Red, Silanes, etc.

If you can't buy NaBH4 I can sell it to you. 100 grs is enough? What do you say about 30 (thirty) dollars + shipping cost? Very cheap huh? Too much cheapper than Mario840 will charge you if you try to buy with him. I'm really just thinking about start selling chemicals here at SM. May be I could start with you!

alking - 30-7-2018 at 14:26

Pd/c is difficult to recover and only reusable once or twice? So long as what you're hydrogenating is dissolved you literally just need to filter the Pd/C off, wash it, and it's good to go again. You'll lose maybe a few percent each time, but not much. You should easily be able to reuse it in the 10's of times, not two. If you could only use it twice no one would use it.

It is expensive but when you consider the ease of use and that you can reuse it numerous times it becomes much more cost effective. If you're only getting 2-3 uses out of yours I'd suspect you're not storing it properly or something, that's not right. You can get it on ebay I know, I'd also check with mario on here (he has a thread in the acquisition subforum).

Loptr - 30-7-2018 at 14:59

Quote: Originally posted by alking

Pd/c is difficult to recover and only reusable once or twice? So long as what you're hydrogenating is dissolved you literally just need to filter the Pd/C off, wash it, and it's good to go again. You'll lose maybe a few percent each time, but not much. You should easily be able to reuse it in the 10's of times, not two. If you could only use it twice no one would use it.

It is expensive but when you consider the ease of use and that you can reuse it numerous times it becomes much more cost effective. If you're only getting 2-3 uses out of yours I'd suspect you're not storing it properly or something, that's not right. You can get it on ebay I know, I'd also check with mario on here (he has a thread in the acquisition subforum).

I have been contemplating acquiring some Pd/C and was wondering what storage guidelines should be followed to insure it doesn't degrade between uses. Also, do you have to use Celite to recover it? It seems that it would be difficult to separate from the Celite while keeping it wet.

Any experiences you guys would like to share?

On a different note, the last couple of days I have been working to try and prepare an activated carbon supported nickel catalyst. I started with an NiCl2 solution that I soaked into some activated carbon and then dried in a dish on a hot plate. I then dumped the activated carbon into an oxalic acid solution with stirring and left it over night. This morning I filtered the solution through a fritted funnel, and plan to continue work up tonight.

The plan is to dry the impregnated activated carbon using the same drying method as before keeping the heat low enough to keep it from decomposing, and then place the impregnated carbon into a two-neck round bottom flask fitted with a dropping funnel filled with water and vacuum adapter. I will apply a vacuum and evacuate the flask and then heat it strongly to decompose the nickel (ii) oxalate to deposit nano nickel powder within the activated carbon. Once I feel that enough heat has been applied, the flask will be cooled down to RT and then flooded with distilled water.

I have no idea what will come out of that flask tonight, but I plan to try this again with more care taken to measuring and weighing, with an attempt to calculate how much nickel is deposited on the activated carbon.

I have some ideas regarding activating it, such as putting it into a beaker with aluminum powder and then pouring in a sat. NaOH solution to generate H2 in-situ, and hopefully "activating" the fine nickel particles in the process. I am hoping to see some activity, and that it isn't too pyrophoric.

I want to try and use this catalyst to hydrogenate cinnamaldehyde with ammonium formate, or something along those lines. Not sure yet. I am hoping to see selective reduction of the double bond, but if reduction does take place, it will likely be both the double bond and the aldehyde to the alcohol, since I have read that happens with other nickel catalysts. Apparently, pyridine can be added to modify the activity of nickel catalysts to selectively reduce the double bond in cinnamaldehyde without reduction to the alcohol.

Any thoughts?

[Edited on 30-7-2018 by Loptr]

One of the other reasons that I am impregnating it on carbon is to be able to easily be able to recover it post-reaction for reuse. The activated carbon that I am using is a little bigger than beach sand at this time, but I plan to vary the mesh size as I go forward. This attempt has been very unscientific, but that will change as I now have very specific questions that I would like to get answered. For one, I have no idea how much nickel oxalate is actually in the activated carbon. There is some on the outside of it for sure, but how much as actually absorbed. Knowing the nickel content of the catalyst is important.

Pretty much expecting a failure this time, but that's how this goes.

[Edited on 30-7-2018 by Loptr]

Chemi Pharma - 30-7-2018 at 15:18

@alking, oh, ok! and may be you think 1 gram is too much powder, huh? The physical loss in the filter paper is around 1/4 of your Platinum or Paladium, mixed with activated charcoal. Losses in the total process plus another 1/4. I just have used Pt/C in the University Lab, never more at my Lab, and I can tell you it's a pain in the ass to recover the catalyst. If you are lucky, you can get to use this 1 gram three times.

By the way, don't spend your time asking Mario about prices. I know him. Even have bought twice with him, but now he is not accepting pay pal no more, just cash by Western Union transfer or bit coins. And his prices? oh, his prices are now more expensive than Sigma Aldrich can charge you.

Mario no more, thanks. I'm thinking seriously start to sell chemicals here at SM to make a competition and force him to put down his prices. I have a legalized Chemical Lab and lmportation/exportation licences and can get whatever chemical you want that has a CAS number, like him. Making profits has a limit. What he's doing have other name: greed! :mad:

clearly_not_atara - 30-7-2018 at 15:28

Al/NiCl2 usually converts nitroalkenes to ketones. There's a Japanese paper about it somewhere if you're interested. I don't think that this rxn counts as "hydrogenation", I think it's just a reduction with metallic nickel generated in situ. According to the mechanism proposed by the authors the nitroalkene is reduced to a nitronate which hydrolyses to the ketone.

Loptr - 30-7-2018 at 16:05

I don't know why I didn't say this earlier, but I do have some papers that use the Raney Nickel activation process to provide the necessary H2 for reductions. Essentially in-situ H2 production.

I will find the paper when I get home.

Al:Ni + H2O + NaOH + substrate --> Raney Nickel + Reduced substrate

[Edited on 31-7-2018 by Loptr]

A simple search yielded an example: http://pubs.ub.ro/dwnl.php?id=CSCC6201504V04S01A0001

[Edited on 31-7-2018 by Loptr]

goldberg - 31-7-2018 at 04:58

Thanks for replies. I'm reading literature and did not found other mentions about problems with activity of Urushibara nickel. Both original papers by Urushibara and books about hydrogenation says that it is comparable to Raney nickel.

I read article about hydrogentaion at atmospheric pressure by Brown and it looks very friendly.
I'm starting to look for materials that i could use if i decide to build apparatus for high pressure hydrogenation.
Typical steel and aluminium alloys will break under influence of hydrogen after enough long time.

Corrosive Joeseph - 31-7-2018 at 05:02

You NEED access to References Forum................

/CJ

Loptr - 31-7-2018 at 06:33

Quote: Originally posted by goldberg

Thanks for replies. I'm reading literature and did not found other mentions about problems with activity of Urushibara nickel. Both original papers by Urushibara and books about hydrogenation says that it is comparable to Raney nickel.

I read article about hydrogentaion at atmospheric pressure by Brown and it looks very friendly.
I'm starting to look for materials that i could use if i decide to build apparatus for high pressure hydrogenation.
Typical steel and aluminium alloys will break under influence of hydrogen after enough long time.

I think most of the time people are not properly preparing Urushibara Nickel, and then turn around and claim that it sucks or doesn't work. Follow the literature to the letter and document your attempts, and then do it several times, and compare your experiences. There is no one shot silver bullet. You have to experiment.

[Edited on 31-7-2018 by Loptr]

Chemi Pharma - 31-7-2018 at 06:58

I really don't know what happen with you, guys.

Even someone showing you the better way to do a decent hydrogenation you insist to follow the bad way. Tell me really why should I spend my time, my efforts and my money with Urushibara nickel or hydrogenation bomb apparatus if I have modern materials like borohydrides complexes, DIBAL, LiAlH4, Silanes, Red and alkyl lithium?

If the goal is to experiment amateur chemistry, and cry over your failures, ok, I appologize, but I think the goal of every amateur chemical is to professionalise himself and do the things better and better. Why insist with old and precarious techniques? To see a big failure? to explode your face with a homemade hydrogen bomb apparatus? I can't believe I'm reading some kind of things.

Oh, come on! no excuses to anyone that claims "oh! I can't get this chemical," Even as an individual person everyone worldwide can get chemicals. At the NET, E-bay, Alibaba, here in SM, with companies, etc. I beg your pardon but no excuses you have to still saying: oh no! This chemical is very hard to purchase.

Let's evolve ourselves and pratice the better chemistry guys. stubbornness will get you nowhere. It's a joke of mine.

Loptr - 31-7-2018 at 08:55

Quote: Originally posted by Chemi Pharma

I really don't know what happen with you, guys.

Even someone showing you the better way to do a decent hydrogenation you insist to follow the bad way. Tell me really why should I spend my time, my efforts and my money with Urushibara nickel or hydrogenation bomb apparatus if I have modern materials like borohydrides complexes, DIBAL, LiAlH4, Silanes, Red and alkyl lithium?

If the goal is to experiment amateur chemistry, and cry over your failures, ok, I appologize, but I think the goal of every amateur chemical is to professionalise himself and do the things better and better. Why insist with old and precarious techniques? To see a big failure? to explode your face with a homemade hydrogen bomb apparatus? I can't believe I'm reading some kind of things.

Oh, come on! no excuses to anyone that claims "oh! I can't get this chemical," Even as an individual person everyone worldwide can get chemicals. At the NET, E-bay, Alibaba, here in SM, with companies, etc. I beg your pardon but no excuses you have to still saying: oh no! This chemical is very hard to purchase.

Let's evolve ourselves and pratice the better chemistry guys. stubbornness will get you nowhere. It's a joke of mine.

Yes, I have most of those as well, but I also don't like the idea of being limited to a harder to get reagent. It is my goal to be able to have a number of options at my disposal. What happens if I can't get the more difficult to obtain reagents in the future?

I might also not want to use my "reserved stock" for some reactions. Why are you being such a blow hard about this?

Chemi Pharma - 31-7-2018 at 09:23

I give up to argue with someone thinking like you.

You have all rights to think like that, but don't ask me to think like you.

Loptr - 31-7-2018 at 09:40

Quote: Originally posted by Chemi Pharma

I give up to argue with someone thinking like you.

You have all rights to think like that, but don't ask me to think like you.

It's obviously a mindset difference considering the topics of your other posts. You come to an amateur chemistry forum and complain about the amateurs still discussing older chemistry, which is generally more accessible.

You are the only one trying to make anyone think differently.

I honestly don't give a f**k what you use or think. If you have something useful to offer, then I will gladly part with that. I take what I need, and leave the rest behind.

[Edited on 31-7-2018 by Loptr]

Also, it's not a matter of not wanting to use the latest and greatest. That stuff is usually EXPENSIVE if you chose to purchase some. I have majority of what you have listed, so I know how much they cost the amateur. I have a lot of NaBH4. It's up for sale right now. I like using it a lot. Very clean reactions. It's also not the end all, be all. I might want more selectivity depending on a functional group present in the molecule. It's not all about reducing imines, nitro groups to amines, or amides to N-alkylamines.

For me, it's more about the journey than the destination.

[Edited on 31-7-2018 by Loptr]

[Edited on 31-7-2018 by Loptr]

Chemi Pharma - 31-7-2018 at 10:02

I'm not complaining about anyone, except of you, a guy that's understand nothing about what I'm defending here. I "didn't come to an amateur chemistry forum". I still here for more than two years and all of your five stars and the time you ingressed in this forum doesn't say nothing to me, cause the time I've been here I met people with much more knowledge in chemistry than me, and I look to learn with them. But, on the other hand, I had an unpleasure to know people like you, arrogant, that think your five stars covers you with a mantle of wisdom, incapable of say bullshits like you say, and make mistakes like any human beeing.

Grow up and turn yourself in a better person. May be I excuse your rudeness and learn to respect your five stars, ok?

Oh, and I'm not the only one trying to make people here think different, ok? Exists more people intelligent here that you think. And for sure they are laughing of you.

Loptr - 31-7-2018 at 10:20

Quote: Originally posted by Chemi Pharma

I'm not complaining about anyone, except of you, a guy that's understand nothing about what I'm defending here.

At this point, I honestly have lost any semblance of a clue I might have had as to what you have been babbling on about or "defending". Defending what? Your right to party? I don't know what I am missing in your posts within this thread, but I am respectfully bowing out as your hubris is too much for me.

[Edited on 31-7-2018 by Loptr]

alking - 31-7-2018 at 10:26

Quote: Originally posted by Chemi Pharma

@alking, oh, ok! and may be you think 1 gram is too much powder, huh? The physical loss in the filter paper is around 1/4 of your Platinum or Paladium, mixed with activated charcoal. Losses in the total process plus another 1/4. I just have used Pt/C in the University Lab, never more at my Lab, and I can tell you it's a pain in the ass to recover the catalyst. If you are lucky, you can get to use this 1 gram three times.

By the way, don't spend your time asking Mario about prices. I know him. Even have bought twice with him, but now he is not accepting pay pal no more, just cash by Western Union transfer or bit coins. And his prices? oh, his prices are now more expensive than Sigma Aldrich can charge you.

Mario no more, thanks. I'm thinking seriously start to sell chemicals here at SM to make a competition and force him to put down his prices. I have a legalized Chemical Lab and lmportation/exportation licences and can get whatever chemical you want that has a CAS number, like him. Making profits has a limit. What he's doing have other name: greed! :mad:

I see what you mean with mechanical losses, it depends upon your scale and equipment. With 1g or less you're of course going to lose a lot more than say with 10g. With 10g you should be able to use the same filter and tools so if you lose even half a gram that's not such a big deal, 5% loss compared to 50%(!). If mechanical losses are a concern and/or you're working with smaller amounts it may be better to get a lesser loaded substrate to mitigate it.

I like Mario, he has helped me out a few times now but some of the things are not worth getting from him, certainly more common things. I assume he is buying from sigma or the like so of course he will have to mark it up a reasonable amount to make it worthwhile for him to sell. Most of us as amateurs cannot buy directly from the big suppliers so that's the price we pay to be able to. With that said I'm sure some competition would be more than welcome, I hope you decide to do so.

Chemi Pharma - 31-7-2018 at 10:50

Thanks @Alking, I will try to make a competition to benefit all SM users until the rest of the year. Do you know? I have quoted some reagents from Mario and got the price from China Chemical suppliers. Mario is charging more than 30 X (yes. You read well. More than thirty times the chinese value) and more than 03 times the price charged from Sigma Aldrich. I have bought goods with Mario. I know how he mislead the country customs. The label withdrawal and etc. For me, as a company, would be very easy export the goods to every SM users with a low price, in dollars and with credit card by Pay Pal. I can withdrawal the labels the same way, repack the goods imported, like I do in my Lab and send like a cleaning product, declaring the value as a few dollars to escape the custom taxes and send it all over the world.

About Pt/C, yes, I had a bad experience with it at the university lab, cause the packs were sent as 1 gram. 1 gram of Platinum is almost nothing. If you breath in front this all the powder will be lost. May be with 10 grams it's better to work with. I never tried with this ammount and I desire to who want to try the best luck as possible. I'd rather the borohydride complexes.

clearly_not_atara - 31-7-2018 at 11:16

Quote: Originally posted by Chemi Pharma

Oh, come on! no excuses to anyone that claims "oh! I can't get this chemical," Even as an individual person everyone worldwide can get chemicals. At the NET, E-bay, Alibaba, here in SM, with companies, etc. I beg your pardon but no excuses you have to still saying: oh no! This chemical is very hard to purchase.

Interesting logic: because you don't have a problem, nobody has the problem. Suppliers won't sell to individuals in many jurisdictions. Most places won't allow you to set up a lab. And the licensing fees cost way more than Pd/C. Plus, complexes are expensive: if you lose 0.25 grams of palladium per run, is it worth paying for 50 grams of Red-Al? Possibly no.

Also, you may be interested in recovery of palladium via dimethylglyoxime:

https://link.springer.com/article/10.1134%2FS002016851314007...

Dimethylglyoxime is made from methyl ethyl ketone, which itself can be made from levulinic acid if it's restricted for some reason.

[Edited on 31-7-2018 by clearly_not_atara]

Chemi Pharma - 31-7-2018 at 11:40

Funny @clearly_not_atara, The discussion I had with @Loptr make me remember an old discussion the two of us had at a thread dealing with Ni/Al and Urushibara nickel reductions. Do you remember? I think you were so rude as Loptr went with me now, in that occasion.

I'm just saying getting chemicals is not a problem anymore to SM members. If you can't get it on the Internet or with a supplier as an individual, SOON, YOU CAN GET WITH ME! Like Mario does in the "Reagents and Apparatus Acquisition" section. With a too much better price! Is it ok for you? Do you want to be my first client?

So, in your oppinion I'm should feel lucky, cause I got a licence to my Chemical Lab, a TAX ID, a custom licence to import and export U$100.000,00/year. No my dear, I tried hard myself to get this licences, paid a high value and invested in my business, although I feel like an amateur yet and have a lot of things to learn with SM Members here, cause here in Brazil happens the same of the rest of the world.

Thanks for the tip on how to recover the catalyst with DMG.

Greetings!

goldberg - 1-8-2018 at 01:13

I am curious of Urushibara nickel because it looks very safe to handle (does not ignite on air etc).
All literature that i have read states that it is comparable to W-7 Raney nickel (Handbook of heterogenous catalysis and
another similar book).

I am looking for material for vessels for slightly higher pressures than atmospheric. Typical stainless steel is not an option
because it will break under influence of hydrogen, aluminium alloys too.
I will first experiment with atmospheric pressure but i'm curious about slightly elevating it.

Herr Haber - 1-8-2018 at 03:16

Would I buy from someone that I dont know, who picks up a fight with 2 SM members in this topic and badmouthes Mario several times just to push his own business ?

Chemi Pharma - 1-8-2018 at 04:05

@Herr Haber, at first you woudn't buy from me as a person, but with a legalized and registered company. Second, if you buy, you wouldn't do me a favor, my company would do a favor for you, cause I'm organizing myself to sell chemicals in my the domestic market and sell to SM members with a low price would be a bonus to the members, just to force a healthy competition with mario. At really I don't need to do so to push my business.

By the way, I never badmouthed of him in this space, I'm just complain about the extremely high prices he is praticising now to sell chemicals. He is a good person in my oppinion, but at the beggining, when I bought with him twice, his prices were more acessible and he accepted international credit cards. Nowadays he just accept cash and his prices are completely out of reality. I think a competition would be good to everyone here.

About pick up a fight with two SM members, wasn't me that began the rudeness. Come on and read the posts the right way. But I'm not a clown to read insults and stay quiet. I have personality.

Finally, don't mix up business with friendship. Nobody is obliged to be a friend of mine here. Discussions about different points of view is very normal at a scientific forum. What can not happen is the discussion descend to the aggression. For this there are the moderators.

Loptr - 1-8-2018 at 04:06

Here are some follow up pics to the Nickel on Carbon catalyst that I am working on. I haven't decomposed the oxalate yet. The charcoal used to be completely black, but now as you can see it has a grey/bluish hue to it.

[Edited on 1-8-2018 by Loptr]

FloridaAlchemist - 1-8-2018 at 05:53

A champagne bottle might work for slightly higher pressure and temperature hydrogenation reactions.

Loptr - 1-8-2018 at 05:59

Quote: Originally posted by FloridaAlchemist

A champagne bottle might work for slightly higher pressure and temperature hydrogenation reactions.

Check out this attachment by Corrosive Joseph. It looks very interesting. I have a pressure bottle already, but the cap is solid.

Attachment: Simple and Inexpensive Alternative to a Medium Pressure Hydrogenation Shaker Type Apparatus.pdf (209kB)
https://www.sciencemadness.org/whisper/files.php?pid=526657&...

From here: https://www.sciencemadness.org/whisper/viewthread.php?tid=86...

[Edited on 1-8-2018 by Loptr]

largenumbergoeshere - 1-8-2018 at 06:04

Just popping by. Do you mind checking your link Loptr - it's not working for me.

Loptr - 1-8-2018 at 06:07

Quote: Originally posted by largenumbergoeshere

Just popping by. Do you mind checking your link Loptr - it's not working for me.

The link works for me. I added another link to the actual post I am talking about. Check that one out.

Chemi Pharma - 1-8-2018 at 07:12

Just posting a study telling about the hazards of pressurized hydrogen laboratory apparatus and the common kind of apparatus to do that, before any SM member here could injury yourself because no one advice them about the risks:

Attachment: hazards associated with homemade hydrogenation apparatus.PDF (2.3MB)
This file has been downloaded 450 times

Loptr - 1-8-2018 at 08:22

Quote: Originally posted by Chemi Pharma

Just posting a study telling about the hazards of pressurized hydrogen laboratory apparatus and the common kind of apparatus to do that, before any SM member here could injury yourself because no one advice them about the risks:

Definitely this. Anytime hydrogen is involved there is always the risk of fire, and particularly more so if using a catalyst that has adsorbed hydrogen gas.

You know the saying: there are old chemists, and there are bold chemists, but not a lot of old bold chemists.

[Edited on 1-8-2018 by Loptr]

Dr.Bob - 1-8-2018 at 16:38

Pd on carbon is sometimes made by coating the carbon with PdCl2 and then reducing in situ, so not hard to make. If you use formic acid or sodium formate as a reducing agent, that will generate H2 on the Pd surface, in a "transfer hydrogenation". Just google it for more info. There are several other chemicals that work. Hydrazine is also good for that, works well with nickel catalysts. You can theoretically reuse Pd/C, but need to keep it moist to avoid fires, so store it wet after recovering it, and then just filter and wash with ethanol to remove the water. Good luck.

Corrosive Joeseph - 1-8-2018 at 22:26

Quote: Originally posted by Dr.Bob

If you use formic acid or sodium formate as a reducing agent, that will generate H2 on the surface, in a "transfer hydrogenation".

Would this work using a Nickel(II) salt to produce Nickel(0).........?

/CJ

Chemi Pharma - 2-8-2018 at 05:51

Ops! sorry, wrong post!

[Edited on 2-8-2018 by Chemi Pharma]

Loptr - 2-8-2018 at 06:51

Quote: Originally posted by Corrosive Joeseph

Quote: Originally posted by Dr.Bob

If you use formic acid or sodium formate as a reducing agent, that will generate H2 on the surface, in a "transfer hydrogenation".

Would this work using a Nickel(II) salt to produce Nickel(0).........?

/CJ

Nickel (II) formate is thermally decomposed to produce finely divided Nickel(0) metal that can be used as a catalyst. This is also on my todo list. It's just that I felt nickel (ii) oxalate would be easier to deposit onto/inside of the activated carbon since it precipitated.