How does chloroform react with potassium tert-butoxide to form dichlorocarbene?

The formation of dichlorocarbene from chloroform and potassium tert-butoxide occurs through an ionic mechanism involving two primary steps.1

First, the strong base, potassium tert-butoxide, performs an acid-base reaction by removing a proton (hydrogen ion) from the chloroform molecule. This process generates a trichloromethide intermediate.1

Second, this intermediate undergoes an elimination process, losing a molecule of potassium chloride to yield the highly reactive dichlorocarbene. Other haloforms, such as those containing bromine or iodine, react in an equivalent manner to produce their respective dihalocarbenes.1