SYNTHESIS OF SPATIALLY-HINDERED METHYLCYCLOALKYLPHENOLS AND SOME PECULIARITIES OF THEIR AMINOMETHYLATION REACTIONS BY AMINOETHYLNONYLIMIDAZOLINE

Abstract

The paper deals with the results of cycloalkylation of phenol with 1-methylcyclopentene, 1(3)-methylcyclohexene in the presence of aluminum phenolate catalyst and influence of various parameters on the yield of the target product. The reaction temperature was varied from 220 to 280 °C, the reaction time - from 1 to 7 h, molar ratio of phenol to cyclene – from 1:1 to 1:3 mol/mol, the catalyst amount – from 10 to 25%. Maximum yield of 2,6-di[1(3)-methylcycloalkyl]phenols is obtained under the following conditions: temperature - 260-280 °C, duration - 5-6 h, molar ratio of phenol to 1(3)-methylcycloalkene - 1:2 mol/mol and the catalyst amount is 20% based on taken phenol. Simultaneously, the yield of the target products - 2,6-di-[1(3)-methylcycloalkyl] phenols is 44.3-47.1% per taken phenol, the selectivity is 67.4 71.2% on the target product. The structure of the synthesized products was determined by 1H NMR and IR spectroscopy. The IR spectra of the samples were recorded on the ALPHA IR Fourier spectrometer (BRUKER company, Germany) in the wave number range of 600–4000 cm-1. The 1H NMR spectra were recorded on the Bruker-300 instrument (Germany) at room temperature of CCl4 with an internal standard, tetramethylsiloxane. As a result of the chromatographic studies of the products of phenol cycloalkylation with 1(3)-methylcycloalkenes in the presence of aluminum phenolate catalyst it became clear that the alkylate mainly contains 2,6-dicycloalkyl-substituted phenols (87.4-92.3%). After rectification of the alkylate at low pressure (20 mm Hg), the target products were obtained with a purity of 96.7-98.1% and their physico-chemical properties were determined. The resulting 2,6-di-[1(3)-methylcycloalkyl]phenols were aminomethylated by formaldehyde and aminoethylnonylimidazoline at the ratio of 1:2:2. From theoretical point of view, Mannich bases were obtained with yield of 65.7-71.7% by the interaction of 2,6-di-[1(3)-methylcycloalkyl]phenols with formaldehyde and aminoethylnonyl imidazoline. Physico-chemical properties of synthesized 4-hydroxy-3,5-di-[1(3)-methylcycloalkyl]benzylaminoethylnonylimidazolines were determined.