Evaluation of a Variation of the Differential Scanning Calorimetry Technique for Measuring Boiling Points of Binary Mixtures at Subatmospheric Pressures

Autor(es)

Troni, Kelly L. ^[1] ; Damaceno, Daniela S. ^[1] ; Ceriani, Roberta ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Fac Chem Engn, BR-13083852 Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF CHEMICAL AND ENGINEERING DATA; v. 65, n. 7, p. 3334-3343, JUL 9 2020.
• Citações Web of Science: 0

Resumo

Boiling points and vapor-liquid equilibrium (VLE) data are crucial for improving modeling and process design. Therefore, considering the experimental determination of these primary thermodynamic properties, a nontraditional technique that has been under study and has shown some advantages is the differential scanning calorimetry (DSC) technique and its variations. Following a previous work focused only on pure compounds, in this work a set of experiments was performed to evaluate in a systematic way the suitability of its suggested variation of the DSC technique for binary mixtures. Its optimized condition for heating rate (24.52 K.min(-1)) and sample size (4.6 +/- 0.5) mg was used at 4.97 kPa with u(P) = 0.12 kPa for 15 different combinations of n-paraffins and/or fatty alcohols (1-alcohols) in binary mixtures (n-paraffin + n-paraffin, 1-alcohol + 1-alcohol, and n-paraffin + 1-alcohol), taking into account the difference between the boiling points (Tb) of the pure compounds at the selected pressure (7 to 63 K). Experiments were configured using the equimolar condition, and pursued effects of this difference on the measured extrapolated onset temperature, that is, the measured boiling point. For four of these mixtures other molar fractions were also tested. Estimations of the boiling points followed the appropriate thermodynamic approach. The results revealed that the optimized condition may fail in some situations for binary mixtures, and that this fail could not always be related to the difference in the boiling points of their pure compounds. Further work is necessary in this direction. (AU)

• Processo FAPESP: 14/21252-0 - Equilíbrio e processos de produção de biocombustíveis e bioprodutos
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• Processo FAPESP: 16/18253-0 - Equilíbrio de fases nas tecnologias de lipídeos e de biocombustíveis
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• Processo FAPESP: 13/12735-5 - Equilíbrio líquido-vapor e equilíbrio líquido-líquido na indústria de óleos, gorduras e biodiesel: dados experimentais, modelagem e simulação
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• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOEN - Regular