Cyclotrimethylene

Cyclotrimethylene is a rarely used name for cyclopropane, the simplest cycloalkane. It describes a ring consisting of three methylene groups (−CH2−) connected in a triangle, giving the chemical formula C3H6. The term is largely obsolete in modern nomenclature; cyclopropane is the preferred name in IUPAC and common usage.

Structure and properties: The cyclopropane ring has internal angles of about 60 degrees, producing significant angle strain and increasing chemical reactivity relative to larger cycloalkanes. Cyclopropane is a colorless, highly flammable gas at room temperature with a boiling point around −33°C. It is relatively insoluble in water and soluble in organic solvents. The ring strain also makes it susceptible to reactions such as electrophilic additions and ring-opening processes, and it can polymerize under certain conditions to give polycyclopropane.

Occurrence and applications: In organic synthesis, cyclopropane rings are valuable building blocks for more complex molecules, and cyclopropane derivatives are used as intermediates in pharmaceuticals and agrochemicals. Historically, cyclopropane was explored as an anesthetic agent, but safety concerns limited its use. The name cyclotrimethylene is encountered mostly in older literature and is not commonly used in contemporary chemical texts.

Safety: Cyclopropane is flammable and may form explosive mixtures with air under certain conditions; handling requires appropriate safety measures in well-ventilated facilities.

See also: Cyclopropane, Cyclopropene, Organic ring strain.