Named Processes and Key Reactions in OC-11

1. Ziegler-Natta Polymerization (1953): Catalyst: TiCl4 + Al(C2H5)3. Uses: HDPE production. Mechanism: coordination polymerization (monomer inserts into Ti–C bond). Result: linear, stereoregular chains. Nobel Prize 1963 (Karl Ziegler + Giulio Natta).

2. Free Radical Polymerization: Initiator decomposes to form R•. Three stages: Initiation → Propagation → Termination. Used for: LDPE, PVC, PS, PAN, Teflon. High pressure required for LDPE (1000–2000 atm) to increase monomer concentration.

3. Vulcanization (Charles Goodyear, 1839): Natural rubber + 2–3% S + heat → S–S cross-links between allylic positions of polyisoprene chains. Product: harder, more elastic, less tacky, better temperature resistance.

4. Bakelite Synthesis (Leo Baekeland, 1907): Stage 1 (acid + phenol:HCHO > 1): novolac (linear, soluble, thermoplastic). Stage 2 (excess HCHO + base/heat): extensive methylene (–CH2–) cross-linking → 3D covalent network (thermosetting Bakelite).

5. Ring-Opening Polymerization of Caprolactam: Initiator: small amount of water or acid/base catalyst. Caprolactam ring opens → amino acid zwitterion → step-growth → Nylon-6. No byproduct — classified as addition polymerization by some systems.

6. Ozone Depletion Cycle (Molina-Rowland, 1974): CFC --[UV]--> Cl•; Cl• + O3 → ClO• + O2; ClO• + O• → Cl• + O2; Net: O3 + O• → 2O2. Cl• is catalytic.

7. Chapman Cycle (natural ozone maintenance): O2 + hν → 2O•; O• + O2 → O3; O3 + hν → O2 + O•; O• + O3 → 2O2. Steady state maintained until CFC disruption.

8. Eutrophication Sequence: N + P nutrients → algal bloom → algae die → bacterial aerobic decomposition → BOD↑ → O2↓ → fish death.

9. Marble Corrosion (Acid Rain): CaCO3 + H2SO4 → CaSO4 (gypsum) + H2O + CO2. Gypsum crust crumbles → irreversible damage to monuments (Taj Mahal effect).