Sciencemadness Discussion Board

Good idea to make my own catalyst?

nannah - 20-1-2014 at 17:40

Hey, i am kind of a "noob", as the kids say, and i´m amazed how much the supply houses are charging for metal catalysts. So i am kind of interested in trying on making my own catalyst for use in org synthesis.

I also wonder if maybe some of you guys are regularely making your own catalysts, or if you are buying it?

Maybe the chemist usually don´t do this on their own, i am pretty curious if i can make it and save a few bucks.
I mean, back in the day, a century ago, chemists were making their own for their needs, not buying their ready-made catalysts, i guess.

I understand, there are probably alot of dangers in doing this too.
So all you master chemists here on the forum. Would you please help a beginner "scientist" straighten out some question marks. :)

Ps. I´m sorry for the sloppy writing. English in not my native language, and i just got off work. So please forgive me if i messed up here and there. :)

/Nannah

Brain&Force - 20-1-2014 at 18:12

What reaction are you attempting? Different reactions require different catalysts, and some are trivially easy to make, such as aluminum chloride (anhydrous) or iron powder.

elementcollector1 - 20-1-2014 at 18:28

For organic reactions, I often hear of palladium on carbon. The carbon part is easy - carbon powder can be made by burning flour. The palladium? Not so much. Short of buying it, the only source available to the amateur is the catalytic converter of a car, which has been discussed before.

Again, not all reactions require the same catalysts - please state something more specific so we can help you further.

Dr.Bob - 20-1-2014 at 18:36

If you find a way to make platinum or palladium, please do let us know, that would be nice to know.

It really depends on if the catalyst is a simple material (one element or mixture of a two or salt) or if the catalyst is a chiral, multis-step compound that cannot be purchased (been there, done that.)

Some simple catalysts are much easier to buy than make.

Zyklon-A - 20-1-2014 at 18:39

I've made a few catalysts, some of which worked well, others however, not so much. Like Brain&Force said, it depends entirely on the reaction you are attempting.
You could most likely do it, but it may not be cheaper in the long run, certainly if you consider time as money. You learn a lot by doing things, but for some things it would be just better to buy it, others are cheaper to make yourself.
Tell us what you are trying to do, than we could help you better.

nannah - 24-1-2014 at 06:33

Thanx guys for taking your time to help me out. :)


I just got so amazed by the price of Pd and Platinum catalyst that i just had to post and ask if i should make it myself. Do you think it could save any money by making it myself.

I am not sure what reaction i am going to do yet, but it seems like these are the catalysts that are the most used.

/Nannah

zed - 24-1-2014 at 15:19

Sure. Just convert some Platinum into Chloroplatinic Acid, dissolve it in ethanol, and reduce it with NaBH4 in ethanol. Makes a very active hydrogenation catalyst.

Whether you buy pre-prepared catalysts or not, you usually end up making your own catalysts.....eventually. Generally speaking, Pd and Pt catalysts are mortal. They gradually lose their catalytic abilities with use, and can no longer be reactivated. Dead catalyst must then be recycled, the metals are recovered, dissolved, and finally precipitated as fresh new catalyst.

Random - 24-1-2014 at 16:01

Quote: Originally posted by elementcollector1  
For organic reactions, I often hear of palladium on carbon. The carbon part is easy - carbon powder can be made by burning flour. The palladium? Not so much. Short of buying it, the only source available to the amateur is the catalytic converter of a car, which has been discussed before.

Again, not all reactions require the same catalysts - please state something more specific so we can help you further.


There is also palladium in MLCCs on circuit boards.

zed - 26-1-2014 at 16:55

Fact is, a single gram of Platinum or Palladium, can often manufacture enough catalyst to produce large amounts of product. Generally Pt or Pd, run about 50 to 75 Dollars per gram, as metal (ebay). If you buy pre-prepared catalysts, naturally, you will pay more....and as stated before.....soon you will be reprocessing your exhausted catalyst anyway.

9kuuby9 - 4-2-2014 at 07:45

Hello Eveyone!

Here is some literature regarding the possible ways of producing Adam's catalyst and some other PGM catalysts.

Platinum Dioxide(Adam's Catalyst)

Platinum dioxide (PtO2) for use in hydrogenations is available commercially. It may
alternatively be prepared by either of the following methods.
Method 1 (from ammonium chloroplatinate) [2]
Place 3.0 g of ammonium chloroplatinate and 30g of sodium nitrate (AnalaR) (Note 4) in
a Pyrex beaker or porcelain dish and heat gently at first until the evolution of gas slackens
and then more strongly until a temperature of 300 °C is reached. This occupies about 15
minutes, and there is no spattering. Maintain the fluid mass at 500 -530 °C for 30
minutes, and allow the mixture to cool. Treat the solid mass with 50 ml of water. The
brown precipitate of platinum oxide (PtO2.H2O) settles to the bottom. Wash it once or
twice by decantation, filter through a hardened filter paper and wash on the filter until
practically free from nitrates. Stop the washing process immediately when the precipitate
tends to become colloidal (Note 5): traces of sodium nitrate do not affect the efficiency of
the catalist. Dry the oxide in a dessicator, weigh out portions of the dried material a
required.

Method 2 (from chloroplatinic acid) [2]

Dissolve 3.5 g of the purest commercial chloroplatinic acid in 10 ml of water contained in
a 250-ml Pyrex beaker or porcelain basin, and add 35 g of sodium nitrate (AnalaR) (Note
4). Evaporate the mixture to dryness by heating gently over a Bunsen flame while stirring
with a glas rod. Then raise the temperature to 350-370°C within about 10 minutes: fusion
will occur accompanied by the evolution of brown oxides of nitrogen and the gradual
separation of a precipitate of brown platinum oxide. If foaming occurs, stir the mixture
more vigorously and direct an additional flame at the top of the reaction mixture, if
necessary. If the burned beneath the beaker is removed when frothing commences, the
top of the fused mass solidifies and material may be carried over the sides of the vessel.
After 15 minutes, when the temperature has reached 400°C, the evolution of gas
decreases considerably. Continue the heating until at the end of 20 minutes the
temperature is 500-550°C; at this stage the evolution of oxides of nitrogen has practically
ceased and there is gentle evolution of gas. Maintain the temperature at this point (best
with the full force of a Bunsen burner) for about 30 minutes, by which time fusion is
complete. Allow the mass to cool (the Pyrex beaker may crack), add 50 ml of water and
proceed as in Method 1.

Method 3 [6]

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 redheat 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.

Preparation of Platinum Oxide from Chloroplatinic Acid [9]

Platinum Oxide for catalytic hydrogenations can be prepared more conveniently from
ammonium chloroplatinate than from chloroplatinic acid by the well-known procedure of
Adams (1). By adding an excess of ammonia to a solution of chloroplatinic acid,
ammonium chloroplatinate is precipitated. This is the basis for a convenient method of
recovering platinum in spent catatlysts (2). The amount of catalyst produced from a given
weight of ammonium chloroplatinate is almost exactly ½ the weight of the ammonium
salt and is therefore very easily calculated. Ammonium chloroplatinate is not hygroscopic
and is therefore weighted more easily than chloroplatinic acid. In starting from the
ammonium salt, no water is used, and hence no spattering occurs in heating the mixture
to the fusion temperature.
By the new procedure a given weight of ammonium chloroplatinate is well mixed with
ten times its weight of powdered sodium nitrate, and the mixture is heated gradually to
the fusion point. During this process much gas is evolved, due presumably to the
decomposition of ammonium nitrate, but the evolution is gentle and no spattering occurs.
The fused mixture is held at 500*C for 25-30 minutes and the platinum oxide is isolated
according to Adam’s directions. From 3.0g of the salt was obtained 1.51g of platinum
oxide, no different in general appearance or activity from that prepared in the usual way.
This experiment has been duplicated in several other laboratories and shortens the
procedure for converting spent catalyst to platinum oxide by 25% or more.

Platinum Recovery [2]

Platinum residues from hydrogenation reactions should be carefully preserved and
subsequently recovered by conversion into ammonium chloroplatinate by the following
method. Dissolve the platinum or platinum residues in aqua regia, evaporate just to
dryness several times with concentrated hydrochloric acid, dissolve the final residue in a
little water and filter. Precipitate ammonium chloroplatinate from the filtrate by addition
of excess of a saturated solution of ammonium chloride. Filter and dry the precipitate at
100°C.

Notes:
Sodium acetate trihydrate can be made from equimolar amounts of acetic acid and an
aqueous solution of sodium hydroxide, followed by concentrating the solution and
filtering off the precipitated NaOAc*3H2O as large clear crystals, which are air
dried. The sodium acetate trihydrate loses its water and becomes powdery
anhydrous NaOAc upon heating over 100°C, so do not heat it too much while
drying it.

Any of the commercial forms of activated charcoal/carbon ("Norit", "Darco", "Big K
Brand", GNC etc.) may be employed; the carbon should be heated on a steam
bath with 10% nitric acid for 2-3 hours, washed free of acid with water and dried
at 100-110°C before use. If the acid washed form of "Norit" charcoal is available,
it may be used directly without further purification.

The filtrates should be clear and colorless; if they show a yellow-orange opalescence,
some of the oxide has become colloidal. The palladium may be recovered [7,8]as
the oxide by evaporating the filtrates to dryness and re-fusing, or as palladium
black by rendering the filtrates slightly alkaline with sodium carbonate and
heating with formaldehyde.

The use of an equivalent quantity of potassium nitrate (AnalaR) is said to produce a
more active catalyst.

It is advisable to test a small portion of the filtrate from platinum by acidifying with
hydrochloric acid and adding a few drops of SnCl2 solution: a yellow or brown
colour develops according to the quantity of platinum present. The yellow colour
is soluble in ether, thus rendering the test more sensitive. If platinum is found,
treat the filtrate with excess of formaldehyde and NaOH solution and heat;
platinum black separates on standing and may be filtered and worked up with
other platinum residues.


References
[1]R. Mozingo, Organic Synthesis Collective Volume 3, 685 (1955)
[2] Vogel's Textbook of Practical Organic Chemistry, 5th ed, p 452-460 (1989)
[3]H. Wieland, Chem. Ber., 45, 484 (1912)
[4]D. Starr, Organic Synthesis Collective Volume 2, p 566
[5]A. Lindlar, Helv. Chim. Acta., 35, 446 (1952)
[6]R. Adams, Organic Synthesis Collective Volume 1, 463 (1941)
[7]R. Adams, J. Am. Chem. Soc. 46, 1684 (1924)
[8]R. Adams, J. Am. Chem. Soc. 47, 1147 (1925)
[9]W. F. Bruce, J. Am. Chem. Soc. 58, 687-688 (1936)

smaerd - 4-2-2014 at 11:20

If you are interested in creating a catalyst for the sake of creating a catalyst there are some that don't appear too difficult to make. Silica sulfuric acid is one I've always wanted to make but have lacked the chlorosulfonic acid to do so. There are tons of ideas out there this was just one I've seen given a lot of use in recent green chemistry literature.

testimento - 4-2-2014 at 14:18

Now as we speak, are impregnated catalysts, like alumina supported V2O5, silver, molybdenum, chromium, nickel and cobalt catalysts out of reach of ordinary amateur chemist? Those contain quite a some of catalysts I'd be interested in.

Secondly, are simple metallic catalysts, like silver ribbon or mesh or V2O5 as a simple powder form totally useless crap, or could they be used in gas phase catalysis as they stand by simply heating them?

Metacelsus - 4-2-2014 at 16:01

Wait... do you mean vaporizing the catalyst (because that won't work; too high temperature). Having vapors of reactants contact the catalyst is more orthodox.

testimento - 4-2-2014 at 17:27

The idea was to submerge silicate balls into conc. solution of silver nitrate, filter, pre-dry and then pyrolyze them in high temp to make silver oxide impregnated silica balls.

Metacelsus - 4-2-2014 at 18:57

Oh, OK. That makes more sense.