Alkali
The word "alkali" is derived from Arabic "al qalīy" (or "alkali"), meaning "the calcined ashes" (see calcination), referring to the original source of alkaline substances. A water-extract of burned plant ashes, called potash and composed mostly of potassium carbonate, was mildly basic. After heating this substance with calcium hydroxide ("slaked lime"), a far more strongly basic substance known as "caustic potash" (potassium hydroxide) was produced. Caustic potash was traditionally used in conjunction with animal fats to produce soft soaps, one of the caustic processes that rendered soaps from fats in the process of saponification, one known since antiquity. Plant potash lent the name to the element potassium, which was first derived from caustic potash, and also gave potassium its chemical symbol K (from the German name Kalium), which ultimately derived from alkali.
Amine alkylation
Industrially, most alkylations are typically conducted using alcohols, not alkyl halides. Alcohols are less expensive than alkyl halides and their alkylation does not produce salts, the disposal of which can be problematic. Key to the alkylation of alcohols is the use of catalysts that render the hydroxyl group a good leaving group. The largest scale "N"-alkylation is the production of the methylamines from ammonia and methanol, resulting in approximately 500,000 tons/y of methylamine, dimethylamine, and trimethylamine. The reaction is poorly selective, requiring separation of the three products. Many other industrially significant alkyl amines are produced, again on a large scale, from the alcohols. Epoxides are another class of halide-free "N"-alkylating agents, useful in the production of ethanolamines.