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. 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.

Some Features of Cycloalkylation Reactions of Phenol with 1-Methylcyclopentene

“…Alkylphenols are mainly obtained by the catalytic alkylation of phenol with aliphatic hydrocarbons [1][2][3][4][5][6][7][8][9][10]. As a catalyst, various acids, alkyl halides, cationites, aluminosilicates, metal oxides, etc.…”