The paper deals with the results of cycloalkylation of phenol with 1-methylcyclopentene, 1(3)-methylcyclohexene in the presence of KU-23 catalyst and influence of various parameters on the yield of the target product. The reaction temperature was varied from 80 to 140 °C, the reaction time - from 2 to 8 h, molar ratio of phenol to cyclene – from 1:2 to 2:1 mol/mol, the catalyst amount – from 5 to 15%. Maximum yield of para-[1(3)-methylcycloalkyl] phenols is obtained under the following conditions: temperature – 110-120 °C, duration – 5-6 h, molar ratio of phenol to 1(3)-methylcycloalkene – 1:1 mol/mol and the catalyst amount is 10% based on taken phenol. Simultaneously, the yield of the target products – para-[1(3)-methylcycloalkyl] phenols is 68.6-73.5% per taken phenol, the selectivity is 91.8-94.3% on the target product. As a result of the chromatographic studies of the products of phenol cycloalkylation with 1(3)-methylcycloalkenes in the presence of KU-23 catalyst it becames clear that the alkylate mainly contains paracycloalkyl-substituted phenols (89.6-94.1%). After rectification of the alkylate at low pressure (10 mm Hg), the target products were obtained with a purity of 97.6-98.2% and their physico-chemical properties were determined. The resulting para-[1(3)-methylcycloalkyl] phenols were aminomethylated by formaldehyde and aminoethylnonylimidazoline at the ratio of 1:2:2. As a result, Mannich bases were obtained with yield of 68.3-76.7% from theory. The synthesized methylcycloalkylbenzylaminoethylnonylimidazolines were tested as antioxidants of M-8 engine oil. The oxidation resistance of the oil has been investigated without the addition and with the addition of ИХП-21 antioxidants, known benzylphenylamines and the compounds of the invention. Addition of the obtained compounds to the base oil leads to enhancement of its antioxidant properties, at application of which viscosity increase is 14.07-15.28%, and precipitate - 0.45-0.57%.
The present study deals with the investigation of catalytic cycloalkylation reactions of phenol with 1-methylcyclopentene. KU-23 and aluminum phenolate were used as catalysts for the process. The effect of kinetic parameters (temperature, duration, molar ratios of the initial components and the amount of catalyst) on the yield and selectivity of methylcyclopentyl phenols obtained as a result of scientific research was investigated. As a result, effective conditions were found for the production of para- and ortho-, ortho- (1-methylcyclopentyl) phenols with high yield and selectivity. It was determined that high yield of target product in the presence of phenol, 1-methylcyclopentene and catalyst KU-23, was 71.2% for phenol and selectivity for target product - 92.8% is obtained under the following conditions of cycloalkylation reaction: temperature 110°C, reaction time-5 hours, molar ratio phenol to methylcyclopentene-1 : 1, the amount of catalyst-10% according to the phenol taken. The cycloalkylation reaction of phenol with 1-methylcyclopentene in the presence of aluminum phenolate catalyst was carried out in an autoclave in a nitrogen environment and effective conditions were found: temperature 260°C, reaction time - 5 hours, molar ratio of phenol to 1-methylcyclopentene 1: 2, amount of catalyst 20% according to the phenol taken. Under these conditions, the yield of the target product is 44.3% for the phenol taken, and the selectivity is 87.6% for the target product. The chemical structures of the synthesized para- and ortho-, ortho- (1-methylcyclopentyl) phenols were confirmed by IR-, 1H and NMR spectroscopy, and physicochemical parameters were determined.
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