为制备新型芳香缓释聚氨酯微胶囊合成了两亲性单体三羟甲基庚烷。以氢氧化钠为催化剂,辛醛和甲醛在较低温度下发生羟醛缩合反应生成2,2-二羟甲基辛醛。提高温度后,2,2-二羟甲基辛醛与甲醛发生康尼扎罗反应生成三羟甲基庚烷。研究了催化剂种类和用量、原料配比、羟醛缩合和康尼扎罗反应温度和反应时间对三羟甲基庚烷摩尔产率的影响。结果表明,优化的合成三羟甲基庚烷的反应条件是n甲醛/n辛醛=4.5,n(NaOH)/n辛醛=1.4,羟醛缩合反应温度和时间分别为35℃和240min,康尼扎罗反应温度和时间分别为55℃和180min,摩尔产率可达88%。用13C核磁共振谱表征了三羟甲基庚烷的化学结构。
Abstract
Trimethylolheptane (TMH) was synthesized through consecutive aldol condensation and Cannizzaro reaction of octylaldehyde and formaldehyde, using sodium hydroxide as catalyst. The effects of varying the amount of catalyst, the ratio of reactants, temperature and time of the Cannizzaro reaction on the yield of TMH were investigated. A yield of 88% for TMH can be obtained by using the optimized synthetic conditions as follows: molar ratio of formaldehyde to octylaldehyde 4.5∶1.0, molar ratio of sodium hydroxide to octylaldehyde 1.4∶1.0, aldol condensation temperature 35℃ and time 240min, Cannizzaro reaction temperature 55℃ and time 180min. The purity of TMH was confirmed by 13C Nuclear Magnetic Resonance (NMR) spectroscopy.
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