【作者】 陈智鹏；

【导师】 李斌；

【作者基本信息】 广西大学 ， 化学工艺， 2013， 博士

【摘要】 金属磷酸盐是一类重要的无机功能材料,能够用作离子交换、吸附、分离材料,离子导体,非均相催化剂,缓释微肥,磁性和光学器件,阻燃剂,具有优异防腐蚀性能的涂料。固相反应具有高选择性、高产率和工艺过程简单等优点,目前已经越来越广泛地应用于固体无机功能材料的合成领域中。本文第一章综述了金属磷酸盐、固相反应的研究进展。对物质进行热分解动力学分析不仅具有理论上的意义,也有实际的应用价值,而选择一个合理的分析方法对进行动力学分析是非常重要的,只有使用合理的分析方法才能得到可靠的计算结果,本文第一章同时对热化学反应动力学分析领域所用到的一些主要理论和分析方法进行了阐述,此外,对本文研究的内容及其意义也进行了说明。以LiH2PO4·H2O, ZnSO4·7H2O和Na2CO3为原料,经过室温条件下的固相反应直接合成得到棱柱状的、单相的LiZnPO4·H2O。XRD的分析结果表明LiZnPO4·H2O是正交晶系结构的化合物。以K3PO4·3H2O、K2HPO4·3H2O和ZnSO4·7H2O为反应物,经80℃下的固相反应合成了单相的KZn2(PO4)(HPO4)。利用固相反应在60℃下分别制备了单相的层状NH4CoPO4·H2O、层状水合磷酸锌镁、NH4ZnPO4-ABW(Ⅱ)和(NH4)2Ce(P04)2·H2O。并通过ICP-AES和XRD分析确定了水合磷酸锌镁的化学式为MgZn2(PO4)2·4H2O。用模型相关法和模型无关法分别计算得到LiZnPO4·H2O热分解反应的动力学三参数,并比较了两种方法的准确性。LiZnPO4·H2O脱水反应的活化能的平均值用等转化率的迭代计算过程求解得到,该值为86.59kJ mol-1。不同转化率对应的活化能的数值表明LiZnPO4·H2O的脱水过程是单步反应机理,该机理属于圆柱收缩机理。LiZnPO4·H2O脱水阶段的指前因子A由活化能和反应机理计算得到。热分解反应的过渡态络合物的一些热力学函数(△S≠,△H≠,△G≠)也同时求解了出来。KZn2(PO4)(HPO4)热分解反应的表观活化能Eα用七种等转化率的方法计算得到,并将各种方法之间的计算精度进行了比较。结果显示活化能Eα的平均值为411.57kJmol-1,并说明了KZn2(PO4)(HPO4)的热分解反应是一个单步的动力学过程,该过程能用唯一的一对动力学三参数[Ea, A, g(a)]来描述。热分解反应的最可能反应机g(α)分别用线性法和比较法来确定。热分解反应的指前因子A由Eα和g(α)计算得到。热分解反应过渡态络合物的一些热力学函数(△S≠,△H≠,△G≠)也同时求解了出来。用等转化率的迭代计算过程求解得到了NH4CoPO4·H2O热分解反应三个阶段和(NH4)2Ce(PO4)2·H2O热分解过程两个阶段的活化能Eα的值,计算结果表明NH4CoPO4·H2O的三个热分解阶段以及(NH4)2Ce(PO4)2·H2O第一阶段的热分解都为单步的动力学过程,都能用各自唯一的一对动力学三参数来描述过程的动力学；而(NH4)2Ce(PO4)2·H2O第二阶段热分解是一个复杂的动力学过程。通过将实验曲线和模型曲线进行比较而推导得到单步动力学过程的热分解反应的最可能反应机理。单步动力学过程的热分解反应的指前因子A由Eα和g(α)计算得到,过渡态络合物的一些热力学函数(△S≠,△H≠,△G≠)也同时求解了出来。MgZn2(PO4)2·4H2O热分解反应两个阶段和NH4ZnPO4-ABW(Ⅱ)热分解反应区域1和区域2的活化能Eα的值用先进等转化率的计算过程求解得到,计算结果表明MgZn2(PO4)2·4H2O两个热分解阶段以及NH4ZnPO4-ABW(Ⅱ)区域1的热分解反应都是单步的动力学过程,都能用各自唯一的一对动力学三参数来描述过程的动力学；而NH4ZnPO4-ABW(Ⅱ)区域2的热分解是一个复杂的动力学过程。单步热分解反应的最可能反应机理通过实验曲线和模型曲线的比较而推导得到。单步动力学过程的热分解反应的指前因子A由Eα和g(α)计算得到。对于复杂热分解反应的动力学过程,本文使用了两种不同的分析方法对其进行了探讨：运用分布活化能模型(DAEM)来研究NH4ZnPO4-ABW(Ⅱ)区域2热分解阶段的复杂动力学过程；运用非线性模型相关法来研究(NH4)2Ce(PO4)2·H2O第二阶段热分解反应的复杂动力学过程。将低热固相反应合成得到的(NH4)2Ce(PO4)2·H2O通过负载H2S04形成H+/(NH4)2Ce(PO4)2·H2O。并考察了H+/(NH4)2Ce(PO4)2·H2O对乙酸异丁酯合成反应的催化活性。在实验中采用均匀设计方案以及数据挖掘技术研究了反应时间、酸醇摩尔比和催化剂用量对酯化率的影响。实验结果表明,当异丁醇用量为0.10mol时,在反应时间为330min,酸醇摩尔比为2.2,催化剂用量为1.4g时,反应的酯化率可达到95.36%。更多还原

【Abstract】 As a kind of very important inorganic function materials, transition metal phosphate can be used for ion exchange, absorption, separation, ionic conductivity, heterogeneous catalyst, fertilizers, magnetic and optical devices, fire retardants and pigments which have good anticorrosion properties. Solid-state reaction is of good selectivity, high output and simplicity, so, this preparation technique is become more and more used extensively in synthesis of inorganic function solid materials. Research progress of the transition metal phosphate and solid-state reaction were summarized in the first chapter. Kinetic analysis of thermal decomposition can have either a practical or theoretical application. And choosing a reliable method plays an impotant role in kinetic analysis of thermal decomposition. The calculations are reliable only when sound kinetic analysis methods, which are showed in the first chapter, are used. Besides, the works about this paper and meaning of this research were demonstrated in the first chapter.The prism-shaped single phase LiZnPO4·H2O was directly synthesized via solid-state reaction at room temperature using LiH2PO4·H2O, ZnSO4·7H2O and Na2CO3as raw materials. XRD analysis showed that LiZnPO4·H2O was a compound with orthorhombic structure. The single phase KZn2(PO4)(HPO4) was synthesized via solid-state reaction at80℃using K3PO4·3H2O, K2HPO4·3H2O and ZnSO4·7H2O as raw materials. Besides, the layered single phase NH4CoPO4·H2O and magnesium zinc phosphate hydrate whose chemical formula was determined as MgZn2(PO4)2·4H2O with ICP-AES and XRD, the single phase NH4ZnPO4-ABW(Ⅱ) and (NH4)2Ce(PO4)2·H2O were prepared via solid-state reaction at60℃.The model-fitting and model-free methods were used to study non-isothermal kinetics of the thermal decomposition reaction of LiZnPO4·H2O, and reliable of this two methods was tested by comparison between their calculated results. Based on the iterative iso-conversional procedure, the average values of the activation energy associated with the thermal dehydration of LiZnPO4·H2O, was determined to be86.59kJ mol-1. Dehydration of the crystal water molecule of LiZnPO4·H2O is single-step reaction that is controlled by contracting cylinder mechanism. The pre-exponential factor A was obtained on the basis of Ea and g(a). Besides, some thermodynamic functions (△S≠,△H≠,△G≠) of the transition state complex of the dehydration reaction of LiZnPO4·H2O were determined. The apparent activation energy Ea associated with the thermal decomposition reaction of KZn2(PO4)(HPO4) was estimated with seven comparative isoconversional procedures. The average value of the apparent activation energy Ea was determined to be411.57kJ mol-1. The thermal decomposition of KZn2(PO4)(HPO4) is a single-step kinetic process and can be described by a unique kinetic triplet [Ea, A, g(a)]. Linear and comparison methods were used to define the most probable reaction mechanism g(a) of the thermal decomposition reaction. The value of pre-exponential factor A was obtained on the basis of Ea and g(a). Besides, some thermodynamic functions (△S≠,△H≠,△G≠) of the transition state complex were also calculated.Based on the iterative isoconversional calculation procedure, the values of activation energy Eα associated with the thermal decomposition stages of NH4CoPO4·H2O and (NH4)2Ce(PO4)2·H2O were obtained, which demonstrate that the three thermal decomposition stages of NH4CoPO4·H2O and the first thermal decomposition stage of (NH4)2Ce(PO4)2·H2O are all single-step kinetic process and can be adequately described by unique kinetic triplets; However, the second stage of the thermal decomposition of (NH4)2Ce(PO4)2·H2O is a kinetically complex process. The most probable reaction mechanisms of the single-step stages were estimated by comparisons between experimental plots and modeled plots. The values of pre-exponential factor A of the single-step stages were obtained on the basis of Ea and the reaction mechanisms, when some thermodynamic functions (△S≠,△H≠,△C≠) of the transition state complexes of the single-step decomposition reaction were calculated.The values of activation energy Eα associated with the thermal decomposition reaction of NH4ZnPO4-ABW(Ⅱ) as well as the two thermal decomposition stages of MgZn2(PO4)2·4H2O were obtained by using the advanced isoconversional calculation procedure, which demonstrate that the two stages of MgZn2(PO4)2·4H2O and the region1of NH4ZnPO4-ABW(Ⅱ) are all a single-step kinetic process and can be adequately described by unique kinetic triplets; but, the region2of NH4ZnPO4-ABW(Ⅱ) is a kinetically complex process. The most probable reaction mechanisms of the single-step processes were estimated by comparisons between experimental plots and modeled results. The values of pre-exponential factor A of the single-step stages were obtained on the basis of Eα and g(a).In this paper, different kinetically complex processes were researched by using two methods:the distributed activation energy model (DAEM) and the nonlinear model-fitting method were applied to study the region2of the thermal decomposition reaction of NH4ZnPO4-ABW(Ⅱ) and the second stage of the thermal decomposition reaction of (NH4)2Ce(PO4)2·H2O in which kinetically complex processes took place, respectively.The (NH4)2Ce(PO4)2·H2O synthesized by using solid-state reaction at low-heating temperature and H2SO4were mixed to obtain H+/(NH4)2Ce(PO4)2·H2O. The synthesis of isobutyl acetate was carried out with H+/(NH4)2Ce(PO4)2·H2O as catalyst, and uniform experimental design as well as data mining technology was applied to the catalytic experiments, in which the effect of the reaction time, the molar ratio of acid to alcohol and the amount of catalyst on the conversion yield of esterification were studied. When the amonnt of isobutyl alcohol was0.10mol, under the optimal reaction conditions, i.e. reaction time of330min,2.2of molar ratio of acid to alcohol and1.4g of catalyst, the conversion yield of esterification was95.36%.更多还原