One-pot synthesis of cyclic aldol tetramer and?,β-unsaturated aldol from linear aldehydes using quat

• 作 者: 许海峰 钟宏 王帅 李方旭
• 出 处: 中南大学学报（英文版）
• 发表日期: 2015年6期
• 关键词: aldol condensation one-pot synthesis phase-transfer catalyst aldehyde

One-pot synthesis of cyclic aldol tetramer anda,β-unsaturated aldol from C3?C8 linear aldehydes using phase-transfer catalyst (PTC), quatary ammonium, combined with sodium hydroxide as catalysts was investigated. Butanal was subjected for detail investigations to study the effect of parameters. It was found that the selectivity of cyclic aldol tetramer depends greatly on the operating conditions of the reaction, especially the PTC/butanal molar ratio. The average selectivity of 2-hydroxy-6-propyl-l, 3, 5-triethyl-3-cyclohexene-1-carboxaldehyde (HPTECHCA) was 54.41% using tetrabutylammonium chloride combined with 14% (mass fraction) NaOH as catalysts at 60 °C for 2 h with a PTC-to-butanal molar ratio of 0.09:1. Pentanal was more likely to generate cyclic aldol tetramer compared with other aldehydes under the optimum experimental conditions. Recovery of the PTC through water washing followed by adding enough sodium hydroxide from the washings was also demonstrated.