关键词: 磁性层状复合氢氧化物, 离子交换, 插层组装, 反应动力学

Abstract: Using the magnetic layered double hydroxides(MLDH) synthesized by co-precipitation as a precursor, the dynamic feature of ion exchange reaction between MLDH and fluorouracil(FU) under the condition of 0-50 ℃ was investigated via the liquid data fitting and solid-phase characterization of MLDH-fluorouracil in situ reaction system. The results show that MLDH and product MLDH-FU belonged principally to a six square crystal series(R-space group) are magnetic compound crystal phase mixed trace iron oxide. The ion exchange rate of MLDH-FU increases significantly with the increase of temperature, and the concentrations varying of three object FU, OH^- and Cl^-, respectively, obey the secondary reaction, zero-order reaction and first-order reaction rate models, the reaction activation energy are 12.69, 27.88 and 3.580 kJ/mol, respectively. Cha-racterization parameters of solid-phase samples change with the liquid kinetic process, object structure adjustment and particle development process of MLDH-FU. Ion exchange limited within interval of LDH layers dones’t affect the internal structure order of layers, and doesn’t change the structure and layered morphology characteristics of precursor, with a non-break-layer reaction behavior. The ion exchange reaction between MLDH and FU is an orderly process started from the absorption affinity of exchange agent FU in MLDH peripheral, lateral offensive, interlayer displacement, and transformation in pillared model to a structure adjustment leaded by the new intercalated object, and grain development process.

Key words: Magnetic layered double hydroxide, Ion exchange, Intercalated assembly, Reaction kinetics