Alkylationof phenol with β-pinene over heterogeneous acid catalysis
Alkylation of phenol with β-pinene at presence of heterogeneous acid catalysts FIBAN K-1, KSF, ZrO2/SO42-, H3PW12O40/TiO2 (HPWO/TiO2) is carried out for the first time. The influence of catalysts nature and reaction temperature upon the structure and composition of products is studied. It has been found, that alkylation at 40°C at the presence of FIBAN K-1 and KSF leads to formation of the optically active para-menthene-phenylic ether with high selectivity (100 and 76 % correspondingly). The reaction under the same conditions at the presence of ZrO2/ SO42- and HPO/TiO2 passes with formation of a significant amount of phenyl-isobornylic ether. The rise of temperature up to 70-100 °C gives an increase in C-alkylated phenol derivatives. KSF is a suitable catalyst for the isocamphyl phenols formation at 100°C. At the presence of all the investigated catalysts at the range of temperatures 40-100°? the formation of para-alkylated derivatives of phenol doesn’t occur.
Alkylphenols are widely used compounds. They apply as inhibitors of thermopolymerization and stabilizers of polymers (1), antioxidants (2-5). Terpenephenols, concerning the same class of compounds, are still insufficiently studied. Meanwhile, isomerization of terpenes at presence of some catalysts (6) opens prospect of obtaining the compounds with various structure depending on conditions of synthesis of terpenephenols. Tests have shown, that mono- and di-substituted orto-terpenephenols are effective as stabilizers of sindyotaktic polystyrenes and elastomers (7) inhibitors of olefin thermopolymerization (8, 9) accelerators of epoxy resin cure (10). Addition of these terpenephenols in polymeric mixes promotes rise in temperature of the beg