METHOD OF PREPARING HIGH-OCTANE ADDITIVE SUCH AS AUTOMOBILE FUEL COMPONENT

petrochemistry. SUBSTANCE: gasoline fraction comprises, wt.%: C4+ olefins, 28-64; aromatic C6+ olefins, 5-35; C5+ naphtenes, 9-21; C4+ paraffins, 5-26; and is prepared from butane-butylene fraction on CBK zeolite-containing catalyst at 250-550 C and 0.1-1.5 MPa and volumetric liquid stock rate of 1-6 . Use is made of plant having preliminary butane-butylene fraction evaporation (heating) unit, stock final heating furnace, stationary catalyst bed reactors, system of heat exchangers and heat recuperation for generating steam or heating butane-butylene fraction, system of separation and recovery of oligomerizate, namely gasoline fraction and catalyst regeneration unit. Said fraction is etherified at 60-120 C 0.05-1.0 MPa, volumetric feed rate of mixture of methanol and gasoline fraction of 0.5-10 , methanol: gasoline fraction weight ratio of 1:12 to 1:40 and etherification degree of at least 70%. Not more than 0.2 wt.% of antioxidant is added to final product. EFFECT: improved properties of the desired product. 2 cl, 1 dwg, 11 ex, 3 tbl