Thermal conductivity and heat capacity of n-heptane, n- and iso-propyl-alcohol at high pressure

• The thermal conductivity, λ, and the heat capacity per unit volume, ρcp, of three molecular liquids, i.e. n-heptane, n-propyl-alcohol and iso-propyl-alcohol, were measured. We used a transient hot-wire method, and the measurements were carried out in a piston-cylinder apparatus with a simple high-pressure cell of novel design. For each substance two isotherms, at room temperature and above, were investigated up to 1.0 GPa. On pressurization a positive sign of the isobaric temperature coefficient of λ, (∂(ln λ)/∂T)P, was observed only for iso-propyl-alcohol. For all three liquids the isothermal volume coefficient of λ, g = -(∂(ln λ)/(∂(ln V)))T, was found to be in the range 2.7–3.1. The isothermal pressure dependence of heat capacity per unit mass was found to be small, except for iso-propyl-alcohol, where a 10–15% decrease in cp was observed. The experimental values of cp were compared with theoretical calculations based on thermodynamics.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

Thermal conductivity

heat capacity

specific heat

high pressure

n-heptane

alkane

alcohol

n-propyl alcohol

iso-propyl alcohol

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