Important Catalysts & Uses
The Ultimate Cheat Sheet for Industrial and Organometallic Catalysis.
In competitive exams like JEE Advanced, JEE Main, and NEET, direct memory-based questions mapping a specific industrial or organic process to its exact catalyst are extremely common. This master guide strips away the fluff and gives you the exact formulas, processes, and "traps" you need to memorize.
1. Major Industrial Inorganic Processes
These are the foundational large-scale chemical manufacturing processes. You must know the reactants, products, and the specific phase of the catalyst.
| Process Name | Reaction | Catalyst Used |
|---|---|---|
| Haber Process | Manufacture of Ammonia ($NH_3$) $N_2 + 3H_2 \rightleftharpoons 2NH_3$ |
Finely divided Iron ($Fe$) Promoter: Molybdenum ($Mo$) |
| Contact Process | Manufacture of Sulfuric Acid (Oxidation of $SO_2$) $2SO_{2(g)} + O_{2(g)} \rightleftharpoons 2SO_{3(g)}$ |
Vanadium pentoxide ($V_2O_5$) or Platinised Asbestos ($Pt$) |
| Ostwald Process | Manufacture of Nitric Acid (Oxidation of $NH_3$) $4NH_3 + 5O_2 \rightarrow 4NO + 6H_2O$ |
Platinum/Rhodium ($Pt/Rh$) gauge catalyst at 500K |
| Lead Chamber Process | Older method for Sulfuric Acid ($SO_2$ oxidation) | Nitric Oxide ($NO_{(g)}$) (Homogeneous Catalysis) |
| Deacon's Process | Manufacture of Chlorine gas $4HCl + O_2 \rightarrow 2Cl_2 + 2H_2O$ |
Cupric chloride ($CuCl_2$) |
| Bosch Process | Water-Gas Shift Reaction (Max $H_2$ yield) $CO + H_2O \rightarrow CO_2 + H_2$ |
Iron Chromate ($Fe_2O_3 + Cr_2O_3$) |
2. Advanced Organic & Organometallic Catalysts
These complex transition metal catalysts are absolute favorites for JEE Advanced coordinate chemistry and organic chemistry sections.
A. Ziegler-Natta Catalyst
Used for the polymerization of ethene into High-Density Polyethylene (HDPE) at low pressures and temperatures. It allows for highly stereoregular linear polymers without branching.
B. Wilkinson's Catalyst
A highly specific catalyst used for the homogeneous hydrogenation of alkenes. It is highly selective (e.g., it will hydrogenate an unhindered double bond but leave a highly substituted one intact).
Chloridotris(triphenylphosphine)rhodium(I)
C. Hydrogenation / Reduction Catalysts
- Lindlar's Catalyst: Used to partially reduce alkynes precisely to cis-alkenes.
Formula: Palladium supported on Calcium Carbonate ($Pd/CaCO_3$), poisoned with Lead acetate or Quinoline to prevent full reduction to alkanes. - Adam's Catalyst: Used for hydrogenation of alkenes and other functional groups.
Formula: Platinum dioxide ($PtO_2$).
3. The Selectivity Trap (Syngas Reactions)
This is the classic demonstration of Catalytic Selectivity. The exact same reactants—Carbon Monoxide ($CO$) and Hydrogen ($H_2$)—will yield three completely different products depending on which catalyst is used.
4. Zeolites and Auto-Catalysis
A. Shape-Selective Catalysis: ZSM-5
Zeolites are microporous aluminosilicates. Their catalytic action depends strictly on their pore structure and the size of the reactant/product molecules fitting inside them.
B. Auto-Catalysis (Self-Catalysis)
In auto-catalysis, no external catalyst is added. One of the products formed during the reaction acts as a catalyst, causing the reaction rate to increase spontaneously as it proceeds.
When $KMnO_4$ is titrated against Oxalic acid in an acidic medium, the reaction starts very slowly. However, as the reaction proceeds, $Mn^{2+}$ ions are formed. These $Mn^{2+}$ ions act as an auto-catalyst, drastically speeding up the subsequent reaction and rapid decolorization.
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