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Title:Phase equilibria of vanillins in compressed gases
Authors:ID Knez, Željko (Author)
ID Škerget, Mojca (Author)
ID Perva-Uzunalić, Amra (Author)
Files:URL http://dx.doi.org/10.1016/j.supflu.2007.06.004
 
Language:English
Work type:Unknown
Typology:1.01 - Original Scientific Article
Organization:FKKT - Faculty of Chemistry and Chemical Engineering
Abstract:Solid-liquid phase transitions of vanillin, ethylvanillin, o-vanillin and o-ethylvanillin in compressed hydrocarbons (isobutane and propane), fluorinated hydrocarbons (R23, R134a and R236fa) and sulphur hexafluoride (SF6) were determined with a modified capillary method in a pressure range between 0.1 and 31.0 MPa. Equilibrium solubilities of vanillins in compressed fluorinated hydrocarbons were determined at temperatures 313.2 and 333.2 K and over a pressure range between 1.1 and 26.0 MPa with a static-analytic method. Experimental solubility data were correlated by a density-based Chrastil model. Results showed that phase equilibria of vanillins in investigated compressed gases are influenced by the type of alchoxy group (methoxy or ethoxy) and the position of OH group (ortho or para), bound to the aromatic ring of solute, as well as the molecular structure of the gas. Three phase SLG curves in p,T-projections mainly exhibited temperature minimums and negative slopes dp/dT, with a maximum melting point depression between 9 and 21 K; all systems with SF6 exhibited a continuous positive slope dp/dT of approximately 4.5 MPa/K. SLG curves with a temperature maximum at low pressure were observed for systems of o-vanillins with R23. Solubilities of o-vanillins in R23 and R236fa were higher in comparison with p-vanillins, whereas, in the case of R134a, the solubilities were influenced by the alchoxy group bound on aromatic ring: vanillin and o-vanillin with methoxy group are more soluble than vanillins with ethoxy group (ethylvanillin and o-ethylvanillin). The highest solubility of all four vanillins was observed in R236fa.
Keywords:solid-liquid-gas equilibria, melting point depression, solubility, vanilin isomers, hydrocarbons, fluorinated hydrocarbons, SF6
Year of publishing:2007
PID:20.500.12556/DKUM-25954 New window
UDC:54
ISSN on article:0896-8446
COBISS.SI-ID:11540502 New window
NUK URN:URN:SI:UM:DK:UJ4DRIH7
Publication date in DKUM:31.05.2012
Views:1914
Downloads:91
Metadata:XML RDF-CHPDL DC-XML DC-RDF
Categories:Misc.
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Record is a part of a journal

Title:The Journal of supercritical fluids
Shortened title:J. supercrit. fluids
Publisher:PRA Press
ISSN:0896-8446
COBISS.SI-ID:25795072 New window

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