Elimination: First Order Carbanion Mechanism
The Elimination first order (carbanion) mechanism involves the ejection of a proton from an organic moiety which generates a carbanion centre (usually stabilised by adjacent electronegative heteroatoms.)

The carbanion centre is quenched by the ejection of a nucleofugal Lewis base which generates a pi-system.

For more information look in the Chemogenesis webbook sections on fragmentation reactions and elimination reactions.