Tabla de Contenidos: “…7.13.2 Wittig Rearrangement -- 7.13.3 Favorskii Rearrangement -- 7.14 Summary -- Problems -- Objective Type Questions -- Chapter 8: Aromatic Substitution -- 8.1 Introduction -- 8.2 Electrophilic Aromatic Substitution (SEAr) -- 8.2.1 Nitration of Benzene -- 8.2.2 Halogenation of Benzene -- 8.2.3 Friedel-Crafts Alkylation -- 8.2.4 Friedel-Crafts Acylation -- 8.2.5 Sulphonation of Benzene -- 8.2.6 Protonation -- 8.3 Reactivity and Orientation in Electrophilic Aromatic Substitution -- 8.4 Groups Donating Electrons by Mesomeric Effect -- 8.5 Groups Withdrawing Electrons by Mesomeric Effect -- 8.6 Groups Withdrawing Electrons by Inductive Effect -- 8.7 Groups Donating Electrons by Inductive Effect -- 8.8 Ortho/Para Ratios -- 8.9 Effects of Multiple Substitution -- 8.10 Hammett Equation -- 8 .11 Nucleophilic Aromatic Substitution -- 8.11.1 By Addition -Elimination Mechanism (SNAr) -- 8.11.2 By Elimination-Addition Mechanism -- 8.12 IPSO Substitution -- 8.13 Summary -- Problems -- Objective Type Questions -- Chapter 9: Stereochemistry -- 9.1 Introduction -- 9.2 Simple Molecules: Hybridization, Conformation and Configuration -- 9.2.1 Hybridization: Methane -- 9.2.2 Hybridization: Ethene and Alkenes -- 9.2.3 Hybridization: Ethyne -- 9.2.4 Bonding and Anti-bonding Orbitals -- 9.2.5 Conformation: Ethane -- 9.2.6 Conformation of propane and n-butane -- 9.2.7 Cydohexane: Chair Conformation -- 9.2.8 Cyclohexane: Boat Conformation -- 9.2.9 inversion of Cyclohexane -- 9.2.10 Monosubstituted Cyclohexanes -- 9.2.11 Disubstituted Cydohexanes -- 9.3 Chiral Molecules -- 9.3.1 Chirality, Enantiomers and Optical Activity -- 9.3.2 How to Specify a Configuration -- 9.3.3 cahn-lngold-Prelog R/S Conventions -- 9.3.4 Enantiomers and Diastereoisomers -- 9.3.5 Racemization -- 9.3.6 Meso Configuration -- 9.3.7 Erythro/Threo and Syn/Anti Configurations -- 9.4 Homochiral Molecules…”

“…Natural gas is a combustible mixture of hydrocarbon gases, primarily methane but also heavier gaseous hydrocarbons such as ethane, propane and butane. Unlike other fossil fuels, natural gas is clean burning and emits lower levels of potentially harmful by-products into the air. …”