alkenebased

Alkenes are a class of unsaturated hydrocarbons characterized by the presence of at least one carbon-carbon double bond. This functional group, the C=C double bond, is the defining feature of alkenes and dictates much of their chemical reactivity. The simplest alkene is ethene, with the molecular formula C2H4. Alkenes are also commonly referred to as olefins.

The presence of the pi bond within the double bond makes alkenes more reactive than their saturated counterparts, alkanes. This pi bond is weaker than the sigma bond and is more accessible to electrophilic attack. Consequently, alkenes readily undergo addition reactions, where atoms are added across the double bond, breaking the pi bond and forming two new sigma bonds. Common addition reactions include halogenation, hydrohalogenation, hydration, and hydrogenation.

Alkenes can be synthesized through various methods, including the dehydration of alcohols and the dehydrohalogenation of alkyl halides. These elimination reactions remove water or hydrogen halide, respectively, to create the double bond. The position and stereochemistry of the double bond are important factors in determining the properties and reactions of an alkene. Geometric isomerism (cis-trans isomerism) can occur in alkenes when each carbon atom of the double bond is attached to two different substituents.

Alkenes are important building blocks in the petrochemical industry. They serve as monomers for the production of many polymers, such as polyethylene and polypropylene, which are ubiquitous in modern life. Ethene, in particular, is a key feedstock for producing a vast array of chemicals, including ethanol, ethylene oxide, and vinyl chloride.