Nomenclature of Alkenes

 Nomenclature of Alkenes

Introduction to Alkenes

 Alkenes

Introduction

Alkenes are hydrocarbons that contain at least one carbon-carbon double bond. They follow the general formula C_nH_2n. A double bond makes them unsaturated and more reactive than alkanes.

Olefins is another name for alkenes, derived from "olefiant gas" (oil-forming gas). This term historically referred to ethene () because it reacts with chlorine to form an oily liquid.

Reactions of Alkanes

 Reactions of Alkanes

1. Halogenation of Alkanes

Halogenation is a substitution reaction where hydrogen atoms in alkanes are replaced by halogens (Cl, Br). The reaction occurs via a free-radical mechanism involving initiation, propagation, and termination steps.

Preparation of Alkanes

Preparation of Alkanes:

1. Hydrogenation

Hydrogenation involves the addition of hydrogen to unsaturated hydrocarbons (alkenes or alkynes) in the presence of a metal catalyst such as Ni, Pd, or Pt, under elevated temperature (250°C).

Synthesis of Tris(ethylenediamine)cobalt(III) Chloride

Synthesis of Tris(ethylenediamine)cobalt(III) Chloride

Objective:

To synthesize tris(ethylenediamine)cobalt(III) chloride [Co(en)₃]Cl₃ ​, an octahedral coordination compound of cobalt(III) that exhibits optical activity.

Nomenclature of Alkanes (IUPAC Rules)

 

Nomenclature of Alkanes (IUPAC Rules):

The IUPAC (International Union of Pure and Applied Chemistry) system provides systematic rules for naming alkanes and other organic compounds. Here are the basic rules for naming alkanes:

Rule 1: Identify the longest continuous carbon chain in the molecule. This chain is referred to as the "parent chain," and its length determines the base name of the molecule (e.g., methane, ethane, propane, etc.).

Introduction to Alkanes and their general properties

Hydrocarbons

The branch of chemistry which deals with the carbon and hydrogen derivatives is called hydrocarbons.

They can be classified into two broad categories:

Aliphatic: These are open-chain molecules, meaning the carbon atoms are arranged in straight or branched chains. They do not contain aromatic rings.

Aromatic: These hydrocarbons have at least one benzene ring (a ring of six carbon atoms with alternating double and single bonds). Benzene rings provide special stability due to the delocalization of $-$electrons.