Author Topic: Catalytic hydrogenation of MDP2P/Nitromethane  (Read 4407 times)

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terbium

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What KrZ said.
« Reply #20 on: April 24, 2002, 07:40:00 AM »

Too make a point:


Referring to:
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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.



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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.


And I say that this is not true.  As I have said before, you will need the same quantity of platinum. The carbon is just an inert carrier and the sulphiding is just a poison to make the catalyst less reactive toward some functional groups.




Organikum

  • Guest
catalysts vs catalysts
« Reply #21 on: April 26, 2002, 06:07:00 AM »

If allowed I sum up:

- there is an advantage in using Pt on C instead Adams catalyst.I do not know why a reduction of 20% of platinum, or more is regarded as insignificant by Terbium. As I lost my platimum mine at Monte Carlo Casino last year I regard this as good information.

- as I read nothing else Adams Catalyst is not reuseable at all, Pt on C can be reused. How often will depend on how clean the used materials are. (right?). The patents state that prolonged usability is the advantage of sulphidized Pt on C. Matthey backs this information up so I would say it should be true. This point is important for bees having not the equipment for a easy recycling/workup of platinum, not everybody is used to aqua regia, what is not very easy to get (yes I know, UTFSE, but in terms of "low profile" it is better if you don´t need it). For the process of sulphidizing is very easy I, just I for myself, would give it a try when preparing Pt/C.

- There is a certain chance that reactions may be run with a far less amount of sulphidized catalyst compared to Pt/C. AFAIK a catalyst is loosing activity very fast at the start of a reaction. This is because of poisoning. Prepoisoned catalysts are said to have an higher activity level over all. Also it should be possible to optimize other parameters like pressure and temperature as "overreduction" will not take place now so soon if at all.

Without tweaking pressure and/or temperature, modified catalysts are probably nonsense in most reactions. With tweaking.......

I would be glad if Terbium could disclose if Platinum black has other advantages over Pt/C or other substrate based catalysts. Where is the secret, for you always name this?


and a little OT:
Is it possible to hydrogenate an aminoalcohol to the correspondending amine  in EtOH or MeOH as solvent with Pd or Pt on C as catalyst and H2SO4 added? This was once called the "MasterPlan". A straight yes or no is all I want. I can offer a few "maybe" in exchange, some handcrafted some bulk. A non fake answer is prefered.




sticks for beating dead cows anyone?
no? OK just asked...
ORGY

mottaman420

  • Guest
-=]DUB[=-
« Reply #22 on: April 26, 2002, 11:37:00 PM »
Adam's catayyst can be reused. And once it is eventually worn out it can be reworked. Like you said "as i read nothing else"<---Maybe you should try reading something else.

Blue Horses + Red Donkeys = Purple Mules

zooligan

  • Guest
Re: As I have said before, you will need the same ...
« Reply #23 on: April 27, 2002, 02:08:00 AM »

As I have said before, you will need the same quantity of platinum. The carbon is just an inert carrier and the sulphiding is just a poison to make the catalyst less reactive toward some functional groups.




I want to preface this with the disclaimer that I don't know shit about real chemistry.  I'm guessing, but I bet that you need less precious metal-on-some carrier catalyst (by metal weight) than PtO2 (by metal weight) because the exposed surface area of the metal-on-carrier is greater with less metal weight than with the PtO2 catalyst.

z


"No one can build his security upon the nobleness of another person." -- Willa Cather

Organikum

  • Guest
reuse of adams catalyst
« Reply #24 on: April 27, 2002, 10:40:00 PM »

mottaman, in the hurry you forgot to point me out the readings on this. I am always interested in valid information on catalyst preparation, reuseability, poisoning  and more. Yes I USFSE but exept in the "large scale production doc" on Rhodiums page I found nothing on this. Might Terbium perhaps share knowledge as he seems to know adams catalyst very well?

If Mr mottaman was only ranting without knowing he may be so kind and suck my dick.
ORGY

mottaman420

  • Guest
Catalysts
« Reply #25 on: April 27, 2002, 11:32:00 PM »
The word catalyst should trigger a few thoughts like it doesn't react but helps another reaction to proceed. Think of the RP meth cookup. You still have the RP at the end. The catalyst can be taken out after the reaction is done. Slight poisining of the catalyst does occur. But you can rework it back into the shit you want. Heres the formula for reworking worn out adam's catalyst. followed by a formula to make adam's catalyst (you said you were intrested in formation recipes).

"Catalysts

Prepare one of the following catalysts, as appropriate to your chosen hydrogenation reaction, following consultation with a Demonstrator:--


Adam's Catalyst3

In a fume cupboard, dissolve chloroplatinic acid (H2PtCl6.6H2O, 0.10 g) in water (ca. 0.5 ml) in a porcelain crucible (3-4 cm diameter). Add sodium nitrate (1 g) and evaporate the mixture to dryness, over a low flame, with continuous stirring. Turn the Bunsen burner full on and stir the contents of the crucible vigorously until the mass has melted completely and the initial decomposition has subsided. Keep the bottom of the crucible at a dull red heat for a further 30 min. (too strong a heat decomposes the oxide to the metal). Allow the crucible to cool and wash the contents into a 250 ml. beaker with hot water from a wash bottle. Filter off the brown platinum oxide with a small ('Hirsch') funnel (Whatman paper No. 541) and wash the oxide with hot water (about 200 ml) until the washings are free from nitrate ion. Dry the catalyst over calcium chloride in a vacuum desiccator.




Palladium Black4

Heat a mixture of palladium chloride (0.50 g) and water (100 ml) to 80deg.C and carefully neutralise the suspension, to wide-range indicator paper, with 20% sodium hydroxide solution (if the end point is overshot, palladium hydroxide precipitates). Add 2.6% formic acid (2.5 ml) and, after about 2 min. make the solution strongly alkaline with 20% sodium hydroxide solution (5 ml). Add more of the formic acid (5 ml) and make sure that the solution is still alkaline. Heat the mixture on a steam bath for 2 hours. Filter off the precipitate with a small ('Hirsch') funnel (Whatman filter paper No. 541), wash it free from alkali and dry it over calcium chloride in a vacuum desiccator.


5% Palladised Charcoal5

Heat decolourising charcoal (7.5 g) on a steam bath for 2-3 hours with conc. hydrochloric acid (5 ml) and water (150 ml). Wash the charcoal by decantation with hot water until free of acid, filter it off, and dry it in an oven at <100deg.C.

Warm palladium chloride (0.5 g) in conc. hydrochloric acid (0.75 ml) and water (5 ml) on the steam bath for ~ 20 min. Add the solution to AnalaR sodium acetate (17.5 g) in water (50 ml) contained in a hydrogenation flask. Introduce the purified charcoal (5.8 g) and hydrogenate the mixture until no more hydrogen is absorbed (~ 2 h). The hydrogenation procedure is described below. Collect the catalyst on a 7 cm Buchner filter (3 thicknesses of Whatman No. 1 filter paper), wash it with water (5 x 100 ml) and drain it on the filter with suction. Dry the catalyst over fresh silica gel in a vacuum desiccator and store it in a tight stoppered bottle.


Lindlar's Catalyst (5% Pd on CaCO3, poisoned with Pb)6

Stir calcium carbonate (precipitated, light; 1.1 g) in water (10 ml) in a flask which is fitted with a thermometer and mounted on a magnetic stirrer/hotplate. Whilst continuing the stirring, add palladium chloride (90 mg) to the suspension and after 5 min., raise the temperature to 80deg.C for a further 10 min. Cool the mixture and transfer it to a hydrogenation flask, using ~ 10 ml of water for rinsing. Hydrogenate the mixture until hydrogen absorption (10-20 ml) is complete (ca. 15 min); the hydrogenation procedure is described below. Collect the reduced catalyst on a small 'Hirsch' funnel (Whatman filter paper No. 1) and wash the catalyst with distilled water (20 ml). Add the damp catalyst to distilled water (10 ml) in a flask on the magnetic stirrer/hotplate. Switch on the stirrer, add a 5% (w/v) solution of AnalaR lead acetate in water (2 ml) and, after 10 min., raise the temperature to 90deg.C for 40 min. During this time, add distilled water, as necessary, to compensate for evaporation losses. Cool the mixture, collect the catalyst on Whatman No. 1 paper in a small 'Hirsch' funnel and wash the catalyst with distilled water (total, ~ 50 ml). Transfer the catalyst to a clean, tared, specimen tube and dry the catalyst in a pistol at 40deg.C to constant weight (~ 1-3 h). Crush the dry catalyst to a powder with a clean spatula or glass rod and stopper and label the tube (catalyst yield: 0.9-1 g)."
Heres the reworking one:
1) dissolve worn out catalyst in aqua regia under a fume hood. This turns platinum into chloroplatinic acid.
2) boil away mixture.
3)Add hydrochloric acid and evaporate until the residue is free of nitrates
4) Now that you have your chloroplatinic acid follow the above mentioned steps to convert it into your adam's catalyst.

This website might help you understand a little about hydrogenations.

http://www.chem.ucalgary.ca/courses/351/Carey/Ch09/ch9-6.html



Oh and a big fuck you to organikum cause he would like me to suck his dick (sorry i'm not gay buddy)



Blue Horses + Red Donkeys = Purple Mules

terbium

  • Guest
rP not catalyst.
« Reply #26 on: April 28, 2002, 01:15:00 AM »
The word catalyst should trigger a few thoughts like it doesn't react but helps another reaction to proceed. Think of the RP meth cookup. You still have the RP at the end. The catalyst can be taken out after the reaction is done.

Phosphorus is not a catalyst in the rP/I reduction of ephedrine. In that reaction the phosphorus is consumed. There is recovery of rP in the end because it is used in large excess.

mottaman420

  • Guest
REUSING!!!! Pt catalysts
« Reply #27 on: April 29, 2002, 06:30:00 AM »
The following excerpts are takin from

https://www.thevespiary.org/rhodium/Rhodium/chemistry/mdma.catalytic.html



From the first section: "The mix was filtered once with vacuum to recover the catalyst (which was rinsed with MeOH), and again through celite to remove the brackish color present due to remaining catalyst particles."

From the 2nd section: "Re-use your PtOIV"
From the third section: "He should use a Buchner filter on a vacuum bottle with Whatman no 401 filtering paper, he expect that other type of filters makes this filtering of the Platinum powder a endless job"
All these readily hint to the fact that you can reuse your catalysts. They make more sense if you read em in context though.
:P  :P  :P

Blue Horses + Red Donkeys = Purple Mules

mottaman420

  • Guest
???
« Reply #28 on: April 29, 2002, 11:45:00 PM »
Would anhydrous magneisum sulfate react with nitromethane, Pt(IV)oxide, methanol, hydrogen or any combination of while under pressure during a catalytic hydrogenation.??
If it wouldn't than couldn't you do a catalytic hyrdogenation with 40% aqueous methylamine or nitromethane without worrying about producing the tertiary amine associated with high water levels. If magnesium sulfate wouldn't work than could you use some other agent to absorb the water without interfering with the reaction.

Blue Horses + Red Donkeys = Purple Mules

SPISSHAK

  • Guest
don`t know about catalysts but Al/Hg
« Reply #29 on: May 23, 2002, 04:57:00 PM »
You can use salt (NaCl) in Al/Hg reductions to bind water I don`t know about catalyst systems though?

Rhodium

  • Guest
NaCl doesn't bind water.
« Reply #30 on: May 23, 2002, 05:48:00 PM »
NaCl doesn't bind water.

terbium

  • Guest
Tertiary amine?
« Reply #31 on: May 23, 2002, 07:34:00 PM »
If it wouldn't than couldn't you do a catalytic hyrdogenation with 40% aqueous methylamine or nitromethane without worrying about producing the tertiary amine associated with high water levels.
I have never heard of this. Can you provide a reference or more details?