Optimization of alkylphenols used as semiproducts in the production of additives on Amberlyst 36Dry macroporous sulfonic acid cation-exchange resin

The synthesis of alkylphenols used as semiproducts in the production of lube oil additives via the alkylation of phenol by ethylene oligomers in the presence of Amberlyst 36Dry macroporous catalyst is studied. The proposed Amberlyst 36Dry sulfonic acid cation-exchange resin allows us to simplify appreciably its pretreatment before use, and to increase the time of its operation, along with the rate, conversion, and selectivity of the process relative to the traditional KU2-8ChS catalyst. Ethylene oligomers containing the maximum amount of vinylidene and internal olefins are established to be most active in alkylation. Linear α-olefins are much less active in alkylation. The ratio of ortho- and para-alkylphenols is generally determined by the temperature and structure of olefins and remains nearly constant with an increase in the process time. The rate of converting alkylphenyl esters into alkylphenols is found to depend on the structure of the ester alkyl radical. Alkylphenols, which fully correspond to the imposed technical requirements as semiproducts used in the production of additives, can be synthesized with a nearly quantitative yield with respect to ethylene oligomers at 135.0°C and a molar ratio ethylene oligomers : phenol = 1.0 : 6.0.