【作者】 王娅玲；

【导师】 王宝和；

【作者基本信息】 大连理工大学 ， 化学工程， 2012， 硕士

【摘要】 碱式氯化镁是一种新型的高功能无机化工产品,可作为阻燃剂、补强增韧剂、填充剂等。而纳米级的碱式氯化镁具有纳米材料的所有特性,这使纳米级碱式氯化镁呈现出特有的的特性,因而备受关注。采用液相法,以六水氯化镁(MgCl2·6H20)和轻质氧化镁(MgO)为原料,合成出碱式氯化镁纳米棒(3Mg(OH)2·MgCl2·8H2O),采用热分析动力学技术处理实验数据,研究碱式氯化镁纳米棒的干燥机理,得到其干燥方程为MR=exp[-(kt)n],干燥速率方程为-dMR/dt=knMR(-lnMR)(?),其中干燥时间指数n=1.808,干燥速率常数k=Aexp(-CT/T)exp(-CLL)=Aexp[-(Ev+RTCLL)/RT]=Aexp[-Ev+Ed)/RT]=Aexp(-E/RT),扩散活化能Ed=RTCLL,表观活化能E=Ev+RTCLL,采用扩散活化能Ed=RTCLL,和等湿分比方法确定碱式氯化镁纳米棒的干燥动力学参数：频率因子A=8.997min-1,界面蒸发活化能Ev=15.399kJ·mol-1,长度常数Q=161.380m-1,温度常数CT=1852.177K。碱式氯化镁纳米棒的干燥过程可以分为三段,分别采用分段函数表示。其中升速阶段的干燥方程为MR=exp[-(kt)n1],干燥速率方程为-dMR/dt=kn1MR(-1nMR)(?)恒速阶段的干燥方程为MR=a-mkt,干燥速率方程为-dMR/dt=mk;降速阶段的干燥方程为MR=exp[-(kt)n2],干燥速率方程为-dMR/dt=kn2MR(-1nMR)(?)采用分子动力学模拟的方法,并以异丙醇分子中各个作用位点为统计对象进行统计平均,对异丙醇分子的气液界面特性进行了研究,探讨了截断半径、温度、薄层切片数Num和分子数N对异丙醇气液界面特性的影响。模拟结果表明,温度T’对气液相主体密度表现出相反的规律,其中气相主体密度随着温度的升高而逐渐增大,液相主体密度则逐渐减小,而界面厚度则逐渐增大；截断半径rc*对气相及液相密度影响不大,当rc*=4.0时,液相主体密度的模拟值与实验值最为接近,rc*=4.0为异丙醇分子模拟时所选取的最佳截断半径,界面厚度则随着截断半径rc*的增大而逐渐减小；随着分子数N的增大,气相主体密度逐渐减小,而液相主体的密度在分子数越多时越接近于实验值,界面厚度则随着分子数的增大而增大；薄层切片数对异丙醇气液界面特性的影响不大,在薄层切片数为200时,其液相主体密度的模拟值接近于实验值。更多还原

【Abstract】 Basic magnesium chloride is a new type of high functional inorganic chemical product, which is often used as flame retardants, hardening filler, filling agent and so on. Basic magnesium chloride nanorods possess the characteristics of nano-materials,which make the nanoscale basic magnesium chloride materials shows the particular property, thus receives more and more attention.Basic magnesium chloride nanorods were prepared by liquid phase method with magnesium chloride hexahydrate and light magnesium oxide.The analysis kinetics method was used to treat the experiental data in order to study the drying mechanism of basic magnesium chloride nanorods.Than,the drying equation MR=exp[-(kt)n]and the drying rate equation-DMR/dt=knMR (-lnMR)(?) were obtained.Thereinto,the drying index n=1.808, the drying rate constant k=Aexp(-CT/T)exp(-CLL)=Aexp[-(Ev+RTCLL)/RT]=Aexp[-(Ev+Ed)/RT]=Aexp(-E/RT),the diffusion activation energy Ed=RTCLL,the apparent activation energy E=Ev+RTCLL. Then, by using the equal moisture ratio method to determine the drying kinetics parameters, the frequency factor A=8.997min-1, the length constant CL=161.380m-1, the activation energy of interface evaporation Ev=15.399kJ·mol-1, and the temperature constant C7=1852.177K were obtained.The drying process of basic magnesium chloride nanorods can be divided into three parts, which got the drying equation and the drying rate equation at different segment.The drying equation in the increasing rate drying period, the constant rate drying period and the decelerating rate drying period are MR=exp[-(kt)n1], MR=a-mkt, MR=exp[-(kt)n2], respectively, and the drying rate equation are-dMR/dt=kn1MR(-lnMR)(?),-dMR/dt=mk,-dMR/dt=kn2MR(-lnMR)(?), respectively.The vapor-liquid interface characteristics of isopropanol were investigated by molecular dynamics simulation(MD),and with the each effect point of isopropanol for object in statistical average method. The distribution regularities of interface characteristics were given, and the influence of cut-off radius, temperature, the number of moleculus and thin slice layer on interface characteristics were studied. The study shows that:The temperature has the opposite influence on the interface characteristics, one of is that with the increase of temperature, the density of gas phase and the interfacial thickness increase gradually, but the density of liquid decreases. The cut-off radius has little effect on the interface characteristics of isopropanol, the simulation value of liquid density is close to experimental value when the rc*=4.0, sorc*=4.0is the optimal cut-off radius for MD of isopropanol,and the interfacial thickness is decreasing with the increase of cut-off radius. The density of gas phase is decreasing with the increase of molecules, whereas, the density of liquid is closer to the experimental value. When the number of thin slice layer was200, the simulation value of liquid density is close to experimental value, but the vapor-liquid interface density and the interfacial thickness had little changed and had no obvious regularity.更多还原