Role of excess molar enthalpies in supercritical antisolvent micronizations using dimethylsulfoxide as the polar solvent

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• 作者：Fouad  ; Zahran ; Jacobo  ; Morè ; re ; Albertina  ; Cabañ ; as ; Juan A.R.  ; Renuncio ; Concepció ; n  ; Pando  ; ;   ; ^{pando@quim.ucm.es}
• 关键词：Supercritical carbon dioxide ; Dimethylsulfoxide ; Excess molar enthalpies ; Supercritical antisolvent precipitation ; Phase equilibria
• 刊名：The Journal of Supercritical Fluids
• 出版年：2011
• 出版时间：December 2011
• 年：2011
• 卷：60
• 期：Complete
• 页码：45-50
• 全文大小：323 K

文摘

The role of excess molar enthalpies in the supercritical antisolvent (SAS) micronizations using dimethylsulfoxide (DMSO) as the polar solvent was investigated. Excess molar enthalpies for CO₂ + DMSO mixtures were measured using an isothermal high-pressure flow calorimeter under conditions of temperature and pressure typically used in SAS micronizations. In most cases, mixtures showed very exothermic mixing. A local temperature increase can be expected in the precipitation chamber as a consequence of the heat evolved when CO₂ dissolves in DMSO. Based on the measurements, local temperature increases were calculated and shown to explain immiscibility of CO₂ and DMSO and agglomerated or irregular particles for average temperature and pressure conditions where complete miscibility and uniform particles could have been expected. data were also discussed in terms of molecular interactions, phase equilibria, density and critical parameters previously reported for CO₂ + DMSO.