【作者】 王珍；

【导师】 王梅；

【作者基本信息】 大连理工大学 ， 应用化学， 2016， 硕士

【摘要】 水滑石类化合物是一种层状的双羟基金属化合物,金属阳离子构成其骨架层板结构,层间由阴离子组成,化学通式是[M2+1-xM3+x（OH）2]x+（An-）x/n·mH2O。层板金属阳离子M2+和M3+可以是不同的金属,层间阴离子An-的选择也具有多样性,这种特性使得水滑石具有广泛的应用,在催化领域的具有广泛的应用前景。本文用共沉淀恒定pH值法将碱金属Ba和Ca、碱土金属K、过渡金属Co和Cu取代层板Mg制备出Mg₃Al₁、Ba₁Mg₂Al₁、Ca1Mg2Al1、K1Mg2Al1、Co3Al1、Mg3Cu1Al1和Co3Cu1Al1类水滑石化合物,用XRD对这几类水滑石的晶型进行了表征,发现用该法制备出的水滑石结晶度高、晶相单一、晶型良好。用氮气吸脱附研究发现这几种水滑石均属于中孔孔径材料,并且出现了Ⅳ型吸脱附等温线。用热重差热分析发现,含碱金属或碱土金属的水滑石一般有两个脱附阶段,第一个阶段是层间水和物理吸附水的脱除,第二个阶段是层间CO32-的脱除,用碱金属或碱土金属取代的水滑石其热稳定性降低。本论文用CO₂-TPD测量了含碱金属或碱土金属的Mg₃Al₁、Ba₁Mg₂Al₁、Ca1Mg2Al1、 K1Mg2Al1表面碱性中心的强度和数量,研究发现固体碱表面碱性中心的数量与金属层板阳离子的金属性相一致,金属性越强,碱性中心的数量越多。同时用渐进法测量了以上几种水滑石及其450‰焙烧产物和750℃焙烧产物的碱性,发现用渐进法测得的水滑石碱性中心数量的多少与用CO₂-TPD测得的结果一致。本文采用Mg₃Al₁、Mg3Cu1Al1、Co3Cu1Al1和Co3Al1类水滑石化合物为催化剂,催化氧化对甲酚制备对羟基苯甲醛,研究了反应液温度、反应时间、氧气流速等因素对该反应的影响,并对氧化反应的机理进行研究。研究发现Co是氧化对甲酚制备对羟基苯甲醛的主催化剂,Cu是有效的助催化剂,即Co3Cu1Al1具有最佳的催化效果。该反应的最佳温度是70℃C,最佳反应时间是12 h,氧气的最佳流速为20 mL/min,在该反应条件下对羟基苯甲醛的收率达72.08%。更多还原

【Abstract】 Hydrotalcite-like compounds （HTLcs） are a kind of solid base, which are also called layered double hydroxides （LDHs）, whose formula are [M2+1-xM3+x（OH）2]x+（An-）x/n·mH2O. M2+ and M3+ are different cations, An- are different anions. Feitknecht have made LDHs for the first time. LDHs have a wide range of application as catalyst.The alkaline-earth metals Ba and Ca, alkali metal K, transition metals Co and Cu replace part of Mg to make the LDHs of Mg₃Al₁、Ba₁Mg₂Al₁、Ca1Mg2Al1、K1Mg2Al1、Co3Al1、 Mg3Cu1Al1 and Co3Cu1Al1. The XRD shows that all of them have a good pattern and the N2 adsorption-desorption implies that they are IV adsorption-desorption isotherm. Using TG-DTA to detect the thermal decomposition, we find that the LDHs have two endothermic peaks, the first stage is the decomposition of interlayer water and phasical adsorption of water, the second stage is the decomposition of CO32-.Using CO₂-TPD detect the basicity and amounts of Mg₃Al₁、Ba₁Mg₂Al₁、Ca1Mg2Al1、 K1Mg2Al1, we find that the amounts of LDHs is consistent with the cationic alkalinity. We also used the titration to detect basicity and amounts of the LDHs、LDO and Spinels. The results of the titration of the LDHs are consistent with the CO₂-TPD.p-hydrox benzaldehyde （PHB） is an important fine chemical intermediates, looking for a right PHB preparation method has a great significance. In this paper we use the LDHs of Mg₃Al₁、Co3Al1、Mg3Cu1Al1 and Co3Cu1Al1 as catalyst to oxide p-cresol to make PHB, we find that Co is esstntial in this reaction, and Cu can improve the selectivity of PHB, the Co3Cu1Al1 has the best resulut. Using Co3Cu1Al1 as catalyst and contral the temperature at 70 ℃, with the flow of oxygen 20 mL/min keeping the reaction for 12 hours, the yield of PHB can attain 72.08%.更多还原