Alkali
In chemistry, an alkali (; from Arabic: "al-qaly" "ashes of the saltwort") is a basic, ionic salt of an alkali metal or alkaline earth metal chemical element. An alkali also can be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The adjective alkaline is commonly, and alkalescent less often, used in English as a synonym for basic, especially for bases soluble in water. This broad use of the term is likely to have come about because alkalis were the first bases known to obey the Arrhenius definition of a base, and they are still among the most common bases.
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.