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Chemistry

Chemistry
Precious Metal Compounds for Catalysis in the Chemical Industry
Today most of the chemical and power-relevant processes in industry are based on catalysts. In a wider sense these are products or devices “accelerating” reactions without being “spent”, and sometimes completing a reaction through this.


Such reactions can mainly be found in chemical and pharmaceutical syntheses. Also the purification of exhaust emissions from stationary plants (heating power stations) and – as is well known – from the automobile industry belongs to the most important field of applied catalysis. All of them are chemical reactions without exception.
Technical catalysts are subdivided into homogeneous and heterogeneous ones. The latter are solids, insoluble in the reaction mixture, and thus always form multiphase systems.
You can find more information about our homogeneous catalysts here .
Among heterogeneous catalysts the supported ones are all-important. For their manufacture a material more or less inert to the reaction conditions (just the “support”, otherwise “carrier”) is coated with the catalytically active substance in the form of aqueous or alcoholic solutions.
According to demand this support can be based on activated carbons, aluminas, silicas, calcium carbonate, zeolites, etc. in various shapes (rings, pellets, extrudates, powders, monoliths, etc.). Here, the chemical reaction of the gaseous or liquid reactants (i.e. starting materials) takes place on the surface of the support impregnated with the effective catalytic substance.
Due to their activities and selectivities, catalysts are mainly based on the platinum group metals (PGM’s) platinum, palladium, rhodium, iridium, ruthenium, but also on the elements gold, silver, and rhenium, and play an important part in chemistry.
Our Chemical Products Business Unit manufactures suitable compounds and their solutions as core products, which serve to coat such catalyst supports
Platinum (Pt)
is widely used in petrochemistry for the so-called reforming (“Platforming”). This means the refining of cuts of crude oil to high-octane fuels. Thus, mainly (cyclo)alkanes are converted into more knock-proof aromatic hydrocarbons. Rhenium (“Rheniforming”), iridium, or tin are applied as co-catalysts.

Several petrochemical isomerization and cracking processes (e.g. the formation of branched alkanes from n-alkanes; the FCC process; dewaxing; the manufacture of para-xylene from meta- and ortho-xylenes; the synthesis of isobutene for producing the additive methyl tert-butyl ether, “MTBE”; etc.), as well as certain oxidation reactions (e.g. the dehydrogenation of alkanes and alkenes) run on supported platinum catalysts, too. The reverse reactions are also feasible, e.g. the reduction of benzene to cyclohexane.

Platinum is also catalytically active to hydrogenations in synthetic chemistry for the reduction of functional groups – e.g. C=C’s, C=O’s, C=N’s – without hydrogenolysis, and of aromatic nitro compounds to aniline derivatives. A specific example is the reductive synthesis of hydroxylamine (NH2OH) from NO with a Pt catalyst.



To GTL catalysts (“Gas to Liquid”) Pt can be applied as co-catalyst, too.



Furthermore, Pt catalysts serve to remove impurities from gases (e.g. carbon monoxide, CO, from hydrogen).

Heraeus’ Pt chemicals for coating are e.g.:

• Dihydrogen hexachloroplatinate(IV) hydrate, H2[PtCl6]•nH2O („CPA“)
• Platinum(II) nitrate, Pt(NO3)2
• cis-Diamminedinitritoplatinum(II) solution, cis-[Pt(NO2)2(NH3)2]
• Tetraammineplatinum(II) chloride hydrate, [Pt(NH3)4]Cl2•nH2O
• Tetraammineplatinum(II) hydrogencarbonate, [Pt(NH3)4](HCO3)2
• Tetraammineplatinum(II) hydroxide solution, [Pt(NH3)4](OH)2
• Tetraammineplatinum(II) nitrate solution, [Pt(NH3)4](NO3)2
• Platinum sulfite solution
• 2-Hydroxyethylammonium hexahydroxoplatinate(IV) solution „Pt EA“
Palladium (Pd)
is an established catalyst metal to manufacture a lot of chemical commodities, e.g. vinyl acetate monomer (“VAM”), hydrogen peroxide (H2O2), methyl iso-butyl ketone (“MIBK”), and highly purified terephtalic acid (“pTA”).

In addition, Pd plays the decisive part in selective hydrogenations of by-products from petrochemical naphta pyrolysis (dienes to monoenes, and alkynes to alkenes). Corresponding to its quantity, Pd is probably the most important precious metal to the hydrogenation processes in chemistry (to hydrogenate alkenes to alkanes, and diketones to hydroxyketones; but also for hydrogenolysis; for isomerizations; for fat hardening; for aminating alcohols; etc.).

To purify gases (e.g. to remove oxygen), Pd is applied, too.

Heraeus offers you for the coating with palladium e.g.:

• Diamminedinitritopalladium(II) solution, [Pd(NO2)2(NH3)2]
• Tetraamminepalladium(II) chloride hydrate, [Pd(NH3)4]Cl2•nH2
• Tetraamminepalladium(II) hydrogencarbonate, [Pd(NH3)4](HCO3)2
• Tetraamminepalladium(II) nitrate solution, [Pd(NH3)4](NO3)2
• Dihydrogen tetrachloropalladate(II) solution, H2[PdCl4]
• Palladium(II) nitrate, Pd(NO3)2
• Sodium tetrachloropalladate(II), Na2[PdCl4]
• Potassium tetrachloropalladate(II), K2[PdCl4]
• Palladium(II) acetate, Pd(OAc)2
Rhodium (Rh)
is used for hydrogenation catalysts, e.g. to produce cyclohexane derivatives from alkyl benzenes, or to reduce C=O’s to alcohols.

Heraeus supplies you with rhodium chemicals for coating supports, e.g.:

• Rhodium(III) chloride hydrate, RhCl3•nH2O
• Rhodium(III) nitrate solution, Rh(NO3)3
• Rhodium sulfite solution
Ruthenium (Ru)
is gaining more and more importance to large-scale syntheses, e.g. to the hydrogenation of C=O groups and aromatic hydrocarbons (e.g. benzene to cyclohexene).

More recent developments are also using Ru catalysts, e.g. the “KAAP” process for the synthesis of ammonia (NH3) from the elements hydrogen (H2) and nitrogen (N2).


Ru as co-catalyst is of interest for the manufacture of GTL catalysts (“Gas to Liquid”).


Heraeus, your partner for Ru coating, e.g. with:

• Ruthenium(III) chloride hydrate, RuCl3•nH2O
• Trinitratonitrosylrutenium(II) solution, [Ru(NO3)3(NO)]
• Ruthenium acetate
Iridium (Ir)
plays a part as co-catalyst to Pt for petrochemical reforming. Besides, supported catalysts based on Ir are sporadically applied to hydrogenations.

A specific application of Ir catalysts is the decomposition of hydrazine (N2H4) into the gaseous elements nitrogen and hydrogen to control satellites.

Heraeus supplies you for Ir coating with e.g.:

• Dihydrogen hexachloroiridate(IV) hydrate, H2[IrCl6]•nH2O
• Iridium(IV) chloride hydrate, IrCl4•nH2O
• Iridium acetate
Gold (Au)
Au mainly serves as a co-catalyst for some large-scale processes, e.g. to manufacture vinyl acetate monomer (“VAM”) with palladium.

Heraeus’ primary Au compound for coating is:

• Hydrogen tetrachloroaurate(III) hydrate, H[AuCl4]•nH2O
Silver (Ag)
Ag is applied on a very large scale to the oxidation of ethene to ethylene oxide (“EO”) with atmospheric oxygen.

Heraeus’ Ag compound for coating is:

• Silver(I) nitrate, AgNO3
Rhenium (Re)
Today Re) represents a common co-metal for supported catalysts on a large scale, e.g. to platinum in petrochemical reforming, and to silver for the manufacture of ethylene oxide.

Re could be used as co-catalyst for the manufacture of GTL catalysts (“Gas to Liquid”).

As the main catalyst, Re is of interest to so-called metathesis reactions of alkenes.

Heraeus is your partner for coating with Re:

• Hydroxotrioxorhenium(VII) solution, [HreO4]
• Ammonium tetraoxorhenate(VII), NH4[ReO4]
We look forward to your enquiries and are at your disposal at any time. Should you not find the product you are searching for, please feel free to contact us.
Our company also offers you the recovery of precious metals from spent supported catalysts. For this, please, visit the web page of our Recycling business unit.

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