TDI交联β-环糊精聚合物的制备及其催化氧化肉桂醛

Preparation of Insoluble β-Cyclodextrin Polymers and Their Catalytic Oxidation for Cinnamaldehyde

摘要:

以β-环糊精(β-CD)为原料, 通过调整交联剂甲苯-2，4-二异氰酸酯（TDI）用量,合成了亲水性能理想的不溶β-环糊精聚合物(β-CDP)。利用红外光谱仪、X-射线衍射、综合热分析仪进行了表征，同时对溶解度和溶胀能力进行了测定。结果表明, TDI与β-CD发生交联后，生成的聚合物保留了β-CD的空腔结构，分解温度提高至350℃。同时，该聚合物在常见溶剂中的溶解度低于0.1%，在水中的溶胀能力仅为0.4mL/g，说明产物在热稳定性、化学稳定性和机械强度等三方面均得到了提高。最后将该聚合物用于肉桂醛氧化生成苯甲醛的反应，催化效果明显，苯甲醛的收率提高至48%，且可重复使用。说明该聚合物不仅保留了β-CD的包结催化性能，并且能够稳定地用于水相有机反应中。

Abstract:

Insoluble β-cyclodextrin polymers (β-CDP) were prepared by β-cyclodextrin (β-CD) with 2,4-diisocyanatotoluene(TDI) as crosslinking agent, and the obtained polymers presented good hydrophilicity by tuning the amount of TDI. They were characterized by FT-IR spectroscopy, X-ray diffraction and thermogravimetric analysis, and their solubility in different solvents as well as their swelling capacity in water were measured. The results indicated that the polymerization between β-CD and TDI indeed occurred. In addition, the decomposition temperature shifted about 350℃, the solubility of β-CDP was lower than 0.1% in the organic solvents and the swell capacity was only 0.4mL/g. All these results showed the improved thermostability, chemical stability and mechanical strength. The β-CDP also presented highly catalytic activity for aqueous oxidation of cinnamaldehyde with hydrogen peroxide as oxidant. The yield of benzaldehyde reached 48% and the CDP was reusable. These results demonstrate that the polymer not only reserve the inclusion ability of β-CD but also can be used for organic reactions in aqueous media.