METHOD OF PREPARING HIGH-OCTANE ADDITIVE CONTAINING METHYL-TERT-BUTYL ETHYL ETHER

petrochemistry. SUBSTANCE: isobutene-containing hydrocarbon mixtures are reacted with methanol and/or ethanol in two stages, each including direct-flow zone(s) and rectification zone to distill hydrocarbons fed into subsequent rectification zone, molar ratio alcohol(s) to tert alkene(s) being maintained at first reaction zone inlet at not lower than 0.7:1; maximum ratio at which product containing alcohol(s) content is obtained within permissible value in first rectification one bottom, and molar ratio of alcohol(s) to tert-alkene(s) is maintained from 1.3:1 to 10:1 at second stage rectification column inlet, and stream with molar ratio of alcohol(s) to ether(s) of less than 0.2:1, preferably more than 2:1, is withdrawn from second rectification zone bottom, this stream is completely or partially recycled into first stage. Alcohol(s) is distributed between first and second stages at ratios from 0.3:1 to 30:1. EFFECT: longer service life of the catalyst. 8 cl, 2 dwg, 7 ex, 2 tbl