Properties of Alkenes
Alkenes have similar physical properties to alkanes. Alkenes are insoluble in water and soluble in nonpolar solvents, such as ether or benzene. They have a lower density than water, and like alkanes, the boiling point of alkenes generally rises with added carbons. Alkenes are also weakly polar and have London dispersion forces but do not exhibit dipole-dipole interactions or hydrogen bonding.
Alkenes are often used as feedstock for chemical manufacture, e.g., ethylene is a feedstock alkene used in the synthesis of poly(ethylene). LDPE is low-density polyethylene and is one of the most ubiquitous polymers. LDPE is used in making trash and grocery bags, squeeze bottles, some household items, and even toys.Alkenes are very abundant in nature in both cyclic and acyclic form. Many pheromones are alkenes and are used in synthetic form as a pharmaceutical. Naturally occurring alkenes are also used extensively in the pharmaceutical industry. One common alkene is beta-carotene. Vitamin A is derived from beta-carotene and is essential for vision. Beta-carotene is also responsible for the color of carrots. Alkanes are generally obtained from petroleum and natural gas and then converted into alkenes.