Improvement on multiparameter equations of state for dimethylsiloxanes by adopting more accurate ideal-gas isobaric heat capacities: Supplementary to P. Colonna, NR Nannan, A. Guardone, EW Lemmon, Fluid Phase Equilib. 244,193 (2006)

摘要

A recent paper by the authors reports ideal-gas isobaric heat capacities (C-P(0)) for several siloxanes. These values were determined using ad hoc speed-of-sound measurements and ab initio calculations. Thermodynamic models for some siloxanes documented in an earlier work by the same authors adopted less accurate estimations for CO(T). This note reports coefficients for the substance-specific Aly-Lee correlations for C-P(0)(T) which ensure higher accuracy when used with the multiparameter equations of state for fluids [(CH3)(2)-Si-O](4) (D-4, octamethylcyclotetrasiloxane), [(CH3)(2)-Si-O](5) (D-5, decamethylcyclopentasiloxane), (CH3)(3)-Si-O-Si-(CH3)(3) (MM, hexamethy[disiloxane), and (CH3)(3)-Si-O-[(CH3)(2)-Si-O](4)-Si-(CH3)(3) (MD4M, tetrad eca methyl hexas i loxa ne), as described in Colonna et al. [P. Colonna, N.R. Narman, A. Guarclone, E.W. Lemmon, Multiparameter equations of state for selected siloxanes, Fluid Phase Equilib. 244 (2)(2006) 193-211].