Abstract The esterification of rosin with pentaerythritol (PE) was studied, using pressurized CO2 as an intensified additive to high-temperature water (HTW), which formed the various esters with different soften points to meet industrial applications. A multiple linear regression model was established to determine the dependence of independent variables (CO2 pressure, temperature, PE-to-rosin mass ratio and reaction time) on rosin conversion, where the elasticity of the logarithm of CO2 pressure was 0.13, indicating pressurized CO2-HTW can effectively enhance this esterification. The conversion of rosin could be improved either by increasing the PE-to-rosin mass ratio or the reaction time, but products were monoester and triesters, respectively, thus the process regulation for the formation of various esters can be achieved through operating conditions. A corresponding stepwise esterification was proposed. Furthermore, the catalytic mechanism of pressurized CO2-HWT for this esterification were identified to be the acid catalysis of carbonic acid and the enhancemennt of CO2.

中文翻译：

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各种松香酯的形成调控及加压 CO2 强化机制

摘要 研究了松香与季戊四醇（PE）的酯化反应，使用加压二氧化碳作为高温水（HTW）的强化添加剂，形成具有不同软化点的各种酯以满足工业应用。建立多元线性回归模型来确定自变量（CO2 压力、温度、PE-松香质量比和反应时间）对松香转化率的依赖性，其中 CO2 压力对数的弹性为 0.13，表明 CO2 加压-HTW可以有效地增强这种酯化。松香的转化率可以通过增加 PE 与松香的质量比或反应时间来提高，但产物分别是单酯和三酯，因此可以通过操作条件来实现对各种酯形成的工艺调节。提出了相应的逐步酯化。此外，加压 CO2-HWT 用于该酯化的催化机制被确定为碳酸的酸催化和 CO2 的增强。