摘要
以枞酸为模型化合物、枞酸与甲醇的酯化为探针反应,采用基团贡献法对枞酸与甲醇酯化反应进行了热力学分析,计算了473～653K、0.1～20MPa反应体系的反应焓变、反应熵变、反应Gibbs自由能变以及反应平衡常数,探讨了温度与压力对酯化反应的影响。计算结果表明,反应的焓变为-46.31～-10.10kJ.mol-1,枞酸与甲醇的甲酯化反应为放热反应;反应Gibbs自由能变为-53.26～-25.49kJ.mol-1,反应为自发过程;标准压力下反应平衡常数为136.32～748.89,5～20MPa下反应平衡常数为(1.1×104)～(3.2×104)。实验结果表明,在无催化剂条件下,超/亚临界甲醇与枞酸酯化反应的转化率分别为85.94%～94.89%、73.80%～81.20%,实验结果与基团贡献法热力学计算值相一致。
The esterification of abietic acid with methanol was selected as a probe reaction. The thermodynamics of reaction was analyzed by group-contribution method. The reaction enthalpy, entropy, Gibbs free energy and equilibrium constant were calculated in the temperature range of 473--653 K and the pressure range of 0.1--20 MPa. The effects of temperature and pressure on the reaction were also discussed. The calculation indicates that the reaction enthalpy is -- 46.31 -- 10.10 kJ . mol-1 and free energy is --53.26--25.49 kJ . mol- 1, showing an exothermic and spontaneous reaction. The equilibrium constant is 136.32 748.89 at standard pressure and （1.1 × 10^4）-（3. 2 × 10^4） in the range of 5-20 MPa. The experimental results show the conversion of abietic acid of 85.94%--94.89% and 73.80%-- 81.20% without catalyst in super/subcritical methanol, which is in agreement with thermodynamic calculation by the group-contribution method.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2013年第6期1900-1906,1905-1906,共7页
CIESC Journal
基金
国家自然科学基金项目(31060102)
广西自然科学基金项目(2010GXNSFA013042)
广西石化资源加工及过程强化技术重点实验室主任基金项目(Z001)~~
关键词
枞酸
甲醇
枞酸甲酯
基团贡献法
热力学
abietic acid
methanol
methyl abietate
group contribution
thermodynamic
