Five intermediates for preparing long chain n-alkylphenol gemini surfactants, bis(2-hydroxy-5-n- alkylphenyl)methanes, were synthesized from fatty acid, phenol, and paraformaldehyde through Friedel- Crafts acylation, esterification, Fries rearrangement, Huang Minlon reduction, and condensation, and their molecular structures were confirmed by NMR, IR spectra and elemental analysis. According to this synthetic route of bis(2-hydroxy-5-n-alkylphenyl)methane, bis(2-hydroxy-5-nonylphenyl)methane has also been synthe-sized by using isononylphenol (industrial product) and paraformaldehyde successfully. It was showed that when n-alkylphenol and paraformaldehyde at a molar ratio of 2∶1 reacted at 130 ℃ for 4 h, the product yield could reach 60% and the alkylphenol conversion and selectivity of product were 63% and 95% respectively.

Key words: paraformaldehyde, n-alkylphenol, bis(2-hydroxy-5-alkylphenyl)methane, synthesis