NOVELTY - An ionic liquid comprising anion and cation, where the cation is nitrogen-containing cation, is new.    USE - The ionic liquid comprising an anion and a cation (primary, secondary or tertiary ammonium ion containing a protonated nitrogen atom) is used as a solvent for enzyme-catalyzed reactions, a solvent for organic synthesis, matrixes in MALDI mass spectrometry, solvent extraction or gas chromatography, catalysis, liquefaction, nuclear fuel reprocessing, fuel cells, electrochemical applications, pervaporation, drug delivery, lubrication, hydraulic fluids, adhesives, sensors, biocides and chromatographic media (all claimed).    ADVANTAGE - The invention provides economical route to the production of ionic liquid. It provides excellent electrical and thermal conductivity while being non-flammable, recyclable and has low toxicity.    DETAILED DESCRIPTION - An ionic liquid comprises anion and cation. The cation is nitrogen-containing cation of structure NHRR'R".    R = hydrocarbyl group optionally substituted with nitrogen-containing functional groups, thio, alkyl thio, sulfonyl, thiocyanate, isothiocyanate, azido, hydrazino, halogen, alkyl optionally interrupted by ether and/or thioether linkages, alkoxy, alkenyl, hydroxy, carbonyl including aldehyde or ketone, carboxyl, boronate, silyl, and/or substituted amino; and    R',R" = H or R, or any two or three of R, R', and R" may be joined together with the N to form cyclic group.    The nitrogen containing functional group is nitrile, nitro, amino, or another basic nitrogen-containing functional group. The carbonyl is aldehyde or ketone. INDEPENDENT CLAIMS are also included for:    (1) preparation of ionic liquid comprising providing organic primary, secondary, or tertiary amine, and neutralizing the compound with acid; and    (2) carrying out an enzyme-catalyzed reaction comprising providing liquid reaction medium containing ionic liquid with anion and cation, providing an enzyme and substrate in liquid reaction for the enzyme, and allowing reaction of the substrate to occur.