Abstract: In the industrial process of oleic acid polymerization，activated clay was used as catalyst. The used clay was generally treated as waste to be buried because of difficult recovery，not only polluting the environment but also causing a waste of raw materials and products. In order to reduce the amount of activated clay，a new technology was studied under carbon dioxide circumstance. The effects of reaction temperature，pressure，mass fraction of clay，mass fraction of Li2CO3，mass fraction of H2O and reaction time on the synthesis process of dimer acid were discussed. The yield of dimer acid was considered a primary evaluating index. Reaction temperature could be elevated from 240 ℃ to 250 ℃when the reaction occurred under 0.5MPa CO2. The new process decreased the amount of activated clay by 25% at the same yield of dimer acid compared to the existing process. Adding carbon dioxide has a good inhibition on decarboxylation，this process decreased the amount of activated clay and made possible oleic acid polymerization at a higher temperatures.

Key words: carbon dioxide, activated clay, dimer acid

摘要： 油酸聚合制备二聚酸的工业化生产过程中，采用活性白土为催化剂，因回收困难等问题，废白土一般作为废物被掩埋，不但污染环境还造成原料和产品浪费。为减少活性白土用量，本文在原工艺基础上，通过通入CO2的方法来抑制油酸脱羧。实验研究了反应温度、压力、白土用量、Li2CO3用量、H2O用量、反应时间等6个因素对油酸二聚反应的影响，得出了适宜的工艺条件。研究结果表明，当通入反应釜中CO2的压力达到0.5 MPa时，反应温度可以从原工艺的240 ℃提高到250 ℃，在相同二聚酸产率和产品指标下，加入CO2的工艺可比不加CO2工艺减少25%的白土使用量。CO2的加入对脱羧有很好的抑制作用，提高了反应温度，减少了催化剂活性白土的使用量。

关键词: 二氧化碳, 活性白土, 二聚酸