硬脂酸镧的制备与动力学研究  

Preparation and Dynamic Study of Lanthanum Stearate

作　　者：叶志强[1] 蒋柏泉[1] 农谷珍[1] 

机构地区：[1]南昌大学环境与化学工程学院,江西南昌330029

出　　处：《稀土》2007年第1期113-116,共4页Chinese Rare Earths

摘　　要：对皂化法制备PVC热稳定剂硬脂酸镧工艺过程中的加料方式进行了部分改进。采用单因素和正交实验方法对反应时间、反应温度、盐碱比、氢氧化钠浓度等因素分别对硝酸镧/氢氧化钠盐碱反应和氢氧化镧/硬脂酸皂化反应的稀土转化率的影响进行了考察,并确定了最优工艺条件和进行了动力学研究。实验结果表明,采用改进的新工艺,稀土转化率高达99.80%以上,硬脂酸镧产品游离酸低于0.3%,熔点为127℃。经实验验证,第一阶段硝酸镧/氢氧化钠盐碱反应为二级反应,动力学方程为-dcA/dt=25.5c2A。第二阶段近似看作氢氧化镧/硬脂酸皂化反应,符合二级反应特征,动力学方程为-dcA/dt=1666c2A。Charging method was partly improved in the technical process for preparing PVC heat steabilizer-- lanthanum stearate by saponifying method. The effects of reaction time, reaction temperature, salt//alkali ratio and NaOH concentration on lanthanum nitrate/sodium hydroxide reaction and lanthanum hydroxide/stearic acid reaction were investigated with single factor method and orthogonal experiment method respectively,the optimal technical conditions for the two reactions were determined and their kinetics was studied. The experimental results showed that the conversion of rare earths reached more than 99.80%, the free acid in the product was less than 0.3% and the melting point of the lanthanum stearate was 127℃ when the partly improved technique was used. The experiments proved that the first stage reaction--lanthanum nitrate/sodium hydroxide reaction was a second order reaction and its kinetic equation was --dcA/dt = 25.5cA^2. The second stage reaction was approximately seen as single lanthanum hydroxide /stearic acid reaction to carry out kinetic research, which was in accordance with the characteristic of second order reaction and the kinetic equation was expressed as --dcA/dt= 1666cA^2.

关 键 词：热稳定剂 镧 硬脂酸镧 皂化反应 稀土 

分 类 号：TQ320.4[化学工程—合成树脂塑料工业] O614.33[理学—无机化学]