Properties and Uses of Alkenes

Introduction

Alkenes are a family of hydrocarbons. All the members of this family have at least one carbon-carbon double bond. Large quantities of alkenes aren’t found in crude oil, instead, they are found by cracking of alkanes. Alkenes are extremely important in the chemical industry; the purest form of alkene is ethene. While ethene by itself cannot be used as fuel, it’s used to manufacture plastics and other chemicals that can be used as fuel. In this article, we will be discussing the physical properties of alkenes, the chemical properties of alkenes and their uses.

Physical properties of Alkenes

Alkenes are a form of unsaturated hydrocarbons. Physically alkenes are very similar to alkanes, they are combustible, are colourless and non-polar.  Due to their physical structure, alkenes can have isomers. Isomeric alkenes are difficult to differentiate by boiling as they tend to have identical or extremely similar boiling points. Moreover, attributing to the carbon-carbon double bond, at room temperature, they are found in the gaseous state, the liquid state, as well as the solid state. Alkenes are lighter than water and are insoluble in water, this is due to the fact that they have weak van der waal forces (van der waal forces are weak electric forces that deal with repulsion and attraction between atoms and molecules), however when alkenes come in contact with organic solvents, new van der waal forces come in place, making the alkenes soluble. The boiling point of alkenes is directly proportional to the molecular structure, the bigger the molecular chain higher the boiling point. 

Chemical Properties of Alkenes

Chemically alkenes are highly reactive, this is due to the fact that they are unsaturated compounds. While alkenes and alkanes are both combustible, alkenes tend to be a lot more reactive in comparison to alkanes due to the fact that most of the chemical reactions that occur within alkenes do at the carbon-carbon double bonds. Alkenes usually go through three primary chemical reactions, firstly on the addition of hydrogen they become alkanes; on the addition of halogens, alkenes produce vicinal dihalides; and on the addition of hydrogen halides, the hydrogen attaches at the carbon-carbon double bond to whichever atom that is attached to more hydrogen atoms and the Halide ion attaches to whichever carbon atom has lesser hydrogen atom. This is known as the Markovnikov rule.

 Uses of Alkenes

Alkenes are extremely useful for humans; they are used in multiple different industries to produce multiple different products. Firstly, and arguably most importantly, they are used to manufacturing polythene. Polythene is used to make polythene bags, as well as to create the plastic that is used to create multiple products, such as plastic cups, plates, bowls, chairs etc. Further ethane -1 2-diol is prepared by alkenes, which is an anti-freezing agent used in motor car radiators. Parts of car radiators and battery cases are manufactured using polystyrene, polystyrene is also manufactured using alkenes. Acrylic fibres are manufactured using alkenes. Alkenes are used to manufacture polypropene; polypropene is used to manufacture a plastic that is used as packaging of several items, as well as to prepare ropes.  Alkenes are used to prepare propanol, propanol is used to prepare acetone, commonly known as nail polish remover. Alkenes are used to manufacture synthetic fibres, as well as to prepare ethanol, i.e. drinking alcohol.

Conclusion

Alkenes are an extremely important family of hydrocarbons that are very beneficial to humans due to the various products that can be prepared using them. They are not abundantly available; alkanes need to be cracked to find them. Their chemical properties are highly affected by the fact that they always carry a carbon-carbon double bond. Their physical properties are quite similar to alkanes, due to the carbon-carbon double bond they can be found in gaseous, liquid as well as solid form at room temperature.