密度泛函理论研究烷基乙醇仲胺溴离子液体表面改性四氧化三铁

Study on[RESA]Br@-COOH@Fe_(3)O_(4) with Density Functional Theory

合成了疏水型烷基乙醇仲胺溴离子液体([RESA]Br),并对羧酸化Fe_(3)O_(4)纳米微球进行了表面改性([RESA]Br@-COOH@Fe_(3)O_(4)),通过核磁共振分析和元素分析进行了结构分析,采用密度泛函理论方法(DFT),在B3LYP/6-311+G(d,p)水平上计算得到离子间作用能、偶极矩和电子结构参数,研究了[RESA]Br的合成机理;测定了在水、甲醇、乙醇、丙酮、乙腈和氯仿中的溶解性能,采用基数法得到亲水疏水平衡值(HLB),并研究了其疏水性能。结果表明,[RESA]Br和[RESA]Br@-COOH@Fe_(3)O_(4)的结构较稳定,且极性较小,除了极性较弱的氯仿,在其余有机溶剂中均不溶解,且它们的HLB值均较小,均匀涂覆在钕铁硼磁体上滴加水珠,依然呈水滴状,其接触角在90°~180°,具有良好的疏水性能。

[RESA]Br hydrophobic ionic liquids(ILs)were synthesized.The surface of-COOH@Fe_(3)O_(4) nanoparticles was modified by[RESA]Br.The structures of[RESA]Br and[RESA]Br@-COOH@Fe_(3)O_(4) were analyzed by 1H NMR spectroscopy and elemental analysis.The structures of[RESA]Br and[RESA]Br@-COOH@Fe_(3)O_(4) have been optimized by Density Functional Theory(DFT)with B3 LYP/6-311+G(d,p).The most stable configurations,interaction energies of ion pairs,dipole moment and electronic structure of[RESA]Br ILs are obtained.The mechanism of[RESA]Br ILs with straight haloalkane was discussed by DFT.The solubilities of[RESA]Br and[RESA]Br@-COOH@Fe_(3)O_(4) in water,methanol,ethanol,acetone,acetonitrile and chloroform were measured at 298 K.The hydrophile-lipophile balance(HLB)values were obtained by using Radix Method and the hydrophobic properties were studied.They are insoluble in all of the solvents except for chloroform.Their HLB values are all small and they have good hydrophobic performance.[RESA]Br@-COOH@Fe_(3)O_(4) nanoparticles coating on the NdFeB are dripped with a water droplet.The water droplet doesn’t wet[RESA]Br@-COOH@Fe_(3)O_(4) nanoparticles’protective layer with oleic acids cladding.It is still in the shape of water droplet.The angle between water droplets and the surface is within 90°~180°.The[RESA]Br@COOH@Fe_(3)O_(4) nanoparticles′protective layer has a good waterproof performance.