| 碱金属无机酸盐催化的硫醇的β-羟乙基化反应 |
| β-Hydroxyethylation of Thiols Catalyzed by Alkali Metal Inorganic Acid Salts |
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| 摘要: 在常压、无溶剂、120℃条件下，考察了14种碱金属无机酸盐（MA，M=Li+，Na+，K+）催化正辛硫醇与碳酸乙烯酯的S-羟乙基化反应性能。普遍的规律是：在阴离子A相同的情况下，钾盐的催化活性高于相应的钠盐，而锂盐无催化活性。在各种无机酸钾盐中，如果共轭酸酸性越强，则相应的钾盐的催化活性越低。为探究钾盐催化剂活化-SH的机理的普适性，以K3PO4为催化剂，考察了在不同反应温度下，6种不同结构的硫醇与碳酸乙烯酯的β-羟乙基化反应催化活性，得出规律是硫醇的酸性越强，其反应活性越高，S-H键越容易解离。该反应无溶剂参与，硫醇与碳酸乙烯酯的物质的量之比接近理论量，产物β-羟乙基硫醚的选择性>99%，产物中无卤素盐副产物生成，易于分离。 |
| 关键词: β-羟乙基化 碱金属无机酸盐 硫醇 β-羟乙基硫醚 |
| 基金项目: 辽宁省自然科学基金指导计划项目（No.20180550246）资助。 |
| Abstract: For the β-hydroxyethylation of sulfur atoms in thiols, there should be a strong interaction between the -SH group and the methylene carbon of ethylene carbonate (EC). However, the nucleophilicity of -SH group is insufficient to interact with the methylene carbon of EC. Therefore, a catalyst should be required to activate -SH group. Under the conditions of atmospheric pressure, solvent-free and 120℃, 14 kinds of alkali metal mineral acid salts (MA, M=Li+, Na+ and K+) were investigated for the S-hydroxyethylation of n-octyl mercaptan with EC. When A- of MA are the same, the ionic radius and polarizability of Li+, Na+ and K+ increase sequentially, the ability of MA to activate SH group also increase sequentially. The general rule is that the catalytic activity of the potassium salt is higher than that of the corresponding sodium salt, while the lithium salt has no catalytic activity. In various inorganic acid potassium salts, the catalytic activity of KA has a positive correlation with the pKa of its corresponding conjugate acid HA. The catalytic activity of KA is lower when its conjugate acid HA is more acidic. In order to explore the universality of the mechanism of potassium salt catalytic activation of -SH, K3PO4 was used as catalyst to investigate the catalytic activity of β-hydroxyethylation of six different structures of thiols with EC at different reaction temperatures. Due to the acidic difference of mercaptan, the rule is that the stronger the acidity of the mercaptan, the higher the reactivity, and the easier the S-H bond is to dissociate. The advantages of the reaction are as follows:no solvent is involved, the molar ratio of mercaptan to EC is close to the theoretical amount, the selectivity of the product β-hydroxyethyl sulfide is >99%, no halogen containing reactant involved and therefore no halogen salt byproduct is formed in the final product. |
| Keywords: β-hydroxyethylation alkali metal inorganic acid salts aliphatic thiols β-hydroxyethyl sulfides |
| 投稿时间：2019-07-10 修订日期：2019-12-22 |
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| 周爽,董永铭,姜恒,李飞,宫红.碱金属无机酸盐催化的硫醇的β-羟乙基化反应[J].无机化学学报,2020,36(4):636-642. |
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