# Isochoric p-{rho}-T and heat capacity C{sub v} measurements on {l_brace}xC{sub 3}H{sub 8} + (1 {minus} x)i-C{sub 4}H{sub 10}, x {approx} 0.7, 0.3{r_brace} from 200 to 400 K at pressures to 35 MPa

## Abstract

The p-{rho}-T relationships and constant volume heat capacity C{sub v} were measured for binary hydrocarbon mixtures containing propane (C{sub 3}H{sub 8}) and isobutane (i-C{sub 4}H{sub 10}). Temperatures ranged from 200 K to 400 K for p-{rho}-T and from 203 K to 342 K for C{sub v} with pressures up to 35 MPa for both measurements. Measurements of p-{rho}-T and C{sub v} were conducted on liquid samples with the mole fraction compositions {l_brace}xC{sub 3}H{sub 8} + (1 {minus} x)i-C{sub 4}H{sub 10}{r_brace} for x = 0.7006 and x = 0.2979. Determinations of saturated-liquid densities were made by extrapolating each isochore to the saturated-liquid pressure and determining the temperature and density at the intersection. Published p-{rho}-T data are in good agreement with this study. For the p-{rho}-T apparatus, the uncertainty of the temperature is 0.03 K, and for pressure it is 0.01% at p > 3 MPa and 0.05% at p < 3 MPa. The principal source of uncertainty in density is the cell volume ({approximately}28.5 cm{sup 3}) with a standard uncertainty of 0.003 cm{sup 3}. When all components of experimental uncertainty are considered, the expanded relative uncertainty (with a coverage factor {kappa} = 2 and thus a two-standard-deviation estimate) of the densitymore »

- Authors:

- National Inst. of Standards and Technology, Boulder, CO (United States)

- Publication Date:

- Sponsoring Org.:
- USDOE, Washington, DC (United States)

- OSTI Identifier:
- 697122

- Resource Type:
- Journal Article

- Journal Name:
- Journal of Chemical and Engineering Data

- Additional Journal Information:
- Journal Volume: 44; Journal Issue: 5; Other Information: PBD: Sep-Oct 1999

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 40 CHEMISTRY; REFRIGERANTS; PROPANE; 2-METHYLPROPANE; SPECIFIC HEAT; BINARY MIXTURES; DENSITY; CHLOROFLUOROCARBONS; MATERIAL SUBSTITUTION

### Citation Formats

```
Duarte-Garza, H.A., and Magee, J.W.
```*Isochoric p-{rho}-T and heat capacity C{sub v} measurements on {l_brace}xC{sub 3}H{sub 8} + (1 {minus} x)i-C{sub 4}H{sub 10}, x {approx} 0.7, 0.3{r_brace} from 200 to 400 K at pressures to 35 MPa*. United States: N. p., 1999.
Web. doi:10.1021/je990090r.

```
Duarte-Garza, H.A., & Magee, J.W.
```*Isochoric p-{rho}-T and heat capacity C{sub v} measurements on {l_brace}xC{sub 3}H{sub 8} + (1 {minus} x)i-C{sub 4}H{sub 10}, x {approx} 0.7, 0.3{r_brace} from 200 to 400 K at pressures to 35 MPa*. United States. doi:10.1021/je990090r.

```
Duarte-Garza, H.A., and Magee, J.W. Wed .
"Isochoric p-{rho}-T and heat capacity C{sub v} measurements on {l_brace}xC{sub 3}H{sub 8} + (1 {minus} x)i-C{sub 4}H{sub 10}, x {approx} 0.7, 0.3{r_brace} from 200 to 400 K at pressures to 35 MPa". United States. doi:10.1021/je990090r.
```

```
@article{osti_697122,
```

title = {Isochoric p-{rho}-T and heat capacity C{sub v} measurements on {l_brace}xC{sub 3}H{sub 8} + (1 {minus} x)i-C{sub 4}H{sub 10}, x {approx} 0.7, 0.3{r_brace} from 200 to 400 K at pressures to 35 MPa},

author = {Duarte-Garza, H.A. and Magee, J.W.},

abstractNote = {The p-{rho}-T relationships and constant volume heat capacity C{sub v} were measured for binary hydrocarbon mixtures containing propane (C{sub 3}H{sub 8}) and isobutane (i-C{sub 4}H{sub 10}). Temperatures ranged from 200 K to 400 K for p-{rho}-T and from 203 K to 342 K for C{sub v} with pressures up to 35 MPa for both measurements. Measurements of p-{rho}-T and C{sub v} were conducted on liquid samples with the mole fraction compositions {l_brace}xC{sub 3}H{sub 8} + (1 {minus} x)i-C{sub 4}H{sub 10}{r_brace} for x = 0.7006 and x = 0.2979. Determinations of saturated-liquid densities were made by extrapolating each isochore to the saturated-liquid pressure and determining the temperature and density at the intersection. Published p-{rho}-T data are in good agreement with this study. For the p-{rho}-T apparatus, the uncertainty of the temperature is 0.03 K, and for pressure it is 0.01% at p > 3 MPa and 0.05% at p < 3 MPa. The principal source of uncertainty in density is the cell volume ({approximately}28.5 cm{sup 3}) with a standard uncertainty of 0.003 cm{sup 3}. When all components of experimental uncertainty are considered, the expanded relative uncertainty (with a coverage factor {kappa} = 2 and thus a two-standard-deviation estimate) of the density measurements is estimated to be 0.05%. For the C{sub v} apparatus, the uncertainty is 0.002 K for the temperature rise and 0.2% for the change-of-volume work, which is the principal source of uncertainty. The expanded relative uncertainty of the heat capacity measurements is estimated to be 0.7%. Hydrocarbon mixtures are considered to be leading candidates to replace chlorofluorocarbon refrigerants, which will be phased out under the terms of the Montreal Protocol.},

doi = {10.1021/je990090r},

journal = {Journal of Chemical and Engineering Data},

number = 5,

volume = 44,

place = {United States},

year = {1999},

month = {9}

}