Key Polymer Synthesis Reactions

1. HDPE (Ziegler-Natta Polymerization): $n \text{CH}_2{=}\text{CH}_2 \xrightarrow{\text{TiCl}_4/\text{Al}(\text{C}_2\text{H}_5)_3,\,\text{low P}} \text{(-CH}_2\text{-CH}_2\text{-)}_n$

2. LDPE (Free Radical Polymerization): $n \text{CH}_2{=}\text{CH}_2 \xrightarrow{1000{-}2000\,\text{atm},\,350{-}570\,\text{K},\,\text{R•}} \text{(-CH}_2\text{-CH}_2\text{-)}_n\,(\text{branched})$

3. Nylon-6,6 (Condensation): $n\,\text{H}_2\text{N-(CH}_2)_6\text{-NH}_2 + n\,\text{HOOC-(CH}_2)_4\text{-COOH} \xrightarrow{-n\,\text{H}_2\text{O}} \text{[-NH-(CH}_2)_6\text{-NH-CO-(CH}_2)_4\text{-CO-]}_n$

4. Nylon-6 (Ring-Opening): $n\,\text{Caprolactam} \xrightarrow{\text{H}_2\text{O or H}^+/\text{OH}^-,\,\Delta} \text{[-NH-(CH}_2)_5\text{-CO-]}_n$

5. Dacron/PET (Condensation): $n\,\text{HOCH}_2\text{CH}_2\text{OH} + n\,\text{HOOC-C}_6\text{H}_4\text{-COOH} \xrightarrow{-n\,\text{H}_2\text{O}} \text{[-O-CH}_2\text{CH}_2\text{-O-CO-C}_6\text{H}_4\text{-CO-]}_n$

6. Bakelite (Condensation + Cross-linking): $\text{C}_6\text{H}_5\text{OH} + \text{HCHO} \xrightarrow{\text{acid/base},\,\Delta} \text{novolac} \xrightarrow{\text{excess HCHO},\,\Delta} \text{Bakelite (cross-linked network)}$

7. Vulcanization of Rubber: $\text{cis-1,4-polyisoprene} + \text{S} (2{-}3\%) \xrightarrow{\text{heat}} \text{vulcanized rubber (S-S cross-links)}$

Key Environmental Chemistry Equations

8. Acid Rain Formation: $\text{SO}_2 + \frac{1}{2}\text{O}_2 \rightarrow \text{SO}_3;\quad \text{SO}_3 + \text{H}_2\text{O} \rightarrow \text{H}_2\text{SO}_4$ $2\text{NO} + \text{O}_2 \rightarrow 2\text{NO}_2;\quad 3\text{NO}_2 + \text{H}_2\text{O} \rightarrow 2\text{HNO}_3 + \text{NO}$

9. Marble Corrosion by Acid Rain: $\text{CaCO}_3 + \text{H}_2\text{SO}_4 \rightarrow \text{CaSO}_4 + \text{H}_2\text{O} + \text{CO}_2$

10. Normal Rain (H2CO3 Formation): $\text{CO}_2 + \text{H}_2\text{O} \rightarrow \text{H}_2\text{CO}_3 \quad (pK_a \approx 6.35;\,\text{rain pH} = 5.6)$

11. Ozone Depletion by CFC-derived Cl•: $\text{CFC} \xrightarrow{\text{UV (stratosphere)}} \text{Cl}^\bullet;\quad \text{Cl}^\bullet + \text{O}_3 \rightarrow \text{ClO}^\bullet + \text{O}_2;\quad \text{ClO}^\bullet + \text{O}^\bullet \rightarrow \text{Cl}^\bullet + \text{O}_2$ $\text{Net:}\quad \text{O}_3 + \text{O}^\bullet \rightarrow 2\text{O}_2\quad(\text{Cl}^\bullet = \text{catalyst, destroys} \sim 10^5\,\text{O}_3)$

12. Carothers Equation: $\bar{X}_n = \frac{1}{1-p} \quad (p = \text{fractional conversion})$