Influence of matrix composition on the solubility of hydroxybenzoic acid isomers in supercritical carbon dioxide
Influence of matrix composition on the solubility of hydroxybenzoic acid isomers in supercritical carbon dioxide
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DOI：
10.1021/ie950649q
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发表时间：
1996-12
影响因子：
4.2
通讯作者：
Frank P. Lucien and;N. Foster
中科院分区：
文献类型：
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作者：
Frank P. Lucien and;N. Foster
对羟基苯甲酸（p-HBA）及其对位和邻位异构体混合物的溶解度在超临界二氧化碳中测定，温度为318和328 K，压力范围为101 ~ 203 bar。p-HBA在二氧化碳中的溶解度（p-HBA/CO2二元体系）比o-HBA的二元体系溶解度低2个数量级。然而，用混合对位和邻位异构体的平衡室进行的测量表明，p-HBA的溶解度有很强的增强。此外，发现这种增强与平衡室的组成无关。二元和三元（p-HBA/o-HBA/CO2）溶解度数据使用Peng - Robinson状态方程的修正形式进行关联。在Peng - Robinson模型中还使用了依赖于体积的混合规则，试图提高溶解度数据的相关性。常规超临界流体（SCF）萃取的异构体混合物能够在一个额外的时间内产生99%纯度的o-HBA。
Solubilities of p-hydroxybenzoic acid (p-HBA) and mixtures of the para and ortho isomers have been determined in supercritical carbon dioxide at 318 and 328 K for pressures in the range 101−203 bar. The solubility of p-HBA in carbon dioxide (p-HBA/CO2 binary system) is 2 orders of magnitude lower than the binary system solubility of o-HBA. However, measurements undertaken with an equilibrium chamber of mixed para and ortho isomers demonstrate a strong enhancement in the solubility of p-HBA. Furthermore, the enhancement was found to be independent of the composition of the equilibrium chamber. The binary and ternary (p-HBA/o-HBA/CO2) solubility data were correlated using a modified form of the Peng−Robinson equation of state. Covolume-dependent mixing rules were also used with the Peng−Robinson model in an attempt to improve the correlation of solubility data. Conventional supercritical fluid (SCF) extraction of a mixture of the isomers is capable of producing an extract which is 99% pure o-HBA in one extr...