RCl

RCl is a general label for organochlorine compounds in which a chlorine atom is bonded to a carbon bearing an R group. The R can be an alkyl or an aryl moiety. Common examples include chloromethane (CH3Cl), benzyl chloride (C6H5CH2Cl), and chlorobenzene (C6H5Cl). Alkyl chlorides feature a polar C–Cl bond and vary in physical state with chain length; aryl chlorides have chlorine attached directly to an aromatic ring.

RCl compounds are typically categorized as primary, secondary, or tertiary alkyl chlorides, reflecting the substitution level of the carbon attached to chlorine. The C–Cl bond is a relatively good leaving group, which makes these compounds reactive in nucleophilic substitution (SN2, SN1) and elimination (E2, E1) reactions. The reactivity and selectivity depend on the substitution pattern: primary chlorides favor SN2, tertiary chlorides favor E2 or SN1.

Preparation methods include direct chlorination of alkanes under radical conditions, and conversion of alcohols to chlorides using reagents such as thionyl chloride (SOCl2), phosphorus trichloride (PCl3), or phosphorus pentachloride (PCl5). Other routes involve substitution of hydroxyl groups or halogen exchange, depending on the substrate and desired product.

Applications of RCl span use as solvents (some chlorinated solvents), intermediates in organic synthesis, and building blocks for polymers, agrochemicals, and pharmaceuticals. Benzyl and allyl chlorides are particularly versatile in further transformations.

Safety and environmental concerns are important: many organochlorides are hazardous, with potential for vapor irritation, toxicity, and persistence in the environment. Proper handling, containment, and disposal are essential.