# Acetic acid (data page)

This page provides supplementary chemical data on acetic acid.

## Material Safety Data Sheet

The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source and follow its directions.
* PTCL Safety web site
* Science Stuff

## Structure and properties

Structure and properties :
| Index of refraction, n$_D$ | 1.3716 |
| Dielectric constant, ε$_r$ | 6.15 ε$_0$ at 20 °C |
| Bond strength | ? |
| Bond length | ? |
| Bond angle | ? |
| Magnetic susceptibility | ? |
| Surface tension | 26.6 dyn/cm at 30 °C |
| Viscosity | 1.222 mPa·sat 20 °C 1.0396 mPa·sat 30 °C 0.7956 mPa·sat 50 °C 0.4244 mPa·sat 110 °C |

## Thermodynamic properties

Phase behavior :
| Triple point | 289.8 K (16.7 °C), ? Pa |
| Critical point | 593 K (320 °C), 57.8 bar |
| Eutectic point with water | –26.7 °C |
| Std enthalpy change of fusionΔ$_{fus}$H$^o$ | +11.7 kJ/mol |
| Std entropy change of fusionΔ$_{fus}$S$^o$ | 40.5 J/(mol·K) |
| Std enthalpy change of vaporizationΔ$_{vap}$H$^o$ | +23.7 kJ/mol |
| Std entropy change of vaporizationΔ$_{vap}$S$^o$ | ? J/(mol·K) |
| Solid properties ||
| Std enthalpy change of formation Δ$_f$H$^o$$_{solid}$ | ? kJ/mol |
| Standard molar entropy S$^o$$_{solid}$ | ? J/(mol K) |
| Heat capacity c$_p$ | ? J/(mol K) |
| Liquid properties ||
| Std enthalpy change of formation Δ$_f$H$^o$$_{liquid}$ | −483.5 kJ/mol |
| Standard molar entropy S$^o$$_{liquid}$ | 158.0 J/(mol K) |
| Enthalpy of combustion, Δ$_c$H$^o$ | –876.1 kJ/mol |
| Heat capacity c$_p$ | 123.1 J/(mol K) |
| Gas properties ||
| Std enthalpy change of formation Δ$_f$H$^o$$_{gas}$ | –438.1 kJ/mol |
| Standard molar entropy S$^o$$_{gas}$ | 282.84 J/(mol K) |
| Heat capacity c$_p$ | 63.4 J/(mol K) |
| van der Waals' constants | a = 1782.3 L$^2$ kPa/mol$^2$ b = 0.1068 liter per mole |

## Vapor pressure of liquid

| P in mm Hg | P in mm Hg | 1 | 10 | 40 | 100 | 400 | 760 | 1520 | 3800 | 7600 | 15200 | 30400 | 45600 |
| T in °C | T in °C | –17.2 | 17.5 | 43.0 | 63.0 | 99.0 | 118.1 | 143.5 | 180.3 | 214.0 | 252.0 | 297.0 | — |
Table data obtained from CRC Handbook of Chemistry and Physics 44th ed.
| Acetic acid vapor pressure vs. temperature. Uses formula: $\scriptstyle P_{mmHg}=10^{7.80307-{\frac {1651.2}{225+T}}}$ for T = 0 to 36 °C $\scriptstyle P_{mmHg}=10^{7.18807-{\frac {1416.7}{211+T}}}$ for T = 36 to 170 °C Formula from Lange's Handbook of Chemistry, 10th ed. | log$_{10}$ of acetic acid vapor pressure vs. temperature. Uses formula: $\scriptstyle \log _{10}P_{mmHg}=7.80307-{\frac {1651.2}{225+T}}$ for T = 0 to 36 °C   $\scriptstyle \log _{10}P_{mmHg}=7.18807-{\frac {1416.7}{211+T}}$ for T = 36 to 170 °C Formula from Lange's Handbook of Chemistry, 10th ed. |

## Distillation data

Vapor-liquid Equilibrium for Acetic acid/Water P = 760 mm Hg :
| BP Temp. °C | mole % water | mole % water |
| BP Temp. °C | liquid | vapor |
| 116.5 | 2.2 | 5.8 |
| 114.6 | 5.4 | 12.3 |
| 113.4 | 8.6 | 16.8 |
| 113.5 | 9.9 | 18.3 |
| 113.1 | 10.1 | 18.8 |
| 110.6 | 18.9 | 29.8 |
| 107.8 | 30.3 | 43.3 |
| 106.1 | 41.3 | 54.5 |
| 104.4 | 52.2 | 64.9 |
| 103.1 | 62.4 | 73.5 |
| 102.3 | 69.6 | 79.2 |
| 101.6 | 77.8 | 85.1 |
| 100.8 | 87.6 | 91.4 |
| 100.5 | 92.3 | 94.4 |
| 100.4 | 94.5 | 96.0 |
| 100.1 | 98.5 | 98.9 |

## Spectral data

UV-Vis :
| λ$_{max}$ | 207 nm (gas phase) |
| Extinction coefficient, ε | ? |
| IR ||
| Major absorption bands | (liquid film) Wave numbertransmittance 2937 cm$^{−1}$26% 2684 cm$^{−1}$41% 2631 cm$^{−1}$39% 2569 cm$^{−1}$49% 1758 cm$^{−1}$19% 1714 cm$^{−1}$4% 1617 cm$^{−1}$66% 1414 cm$^{−1}$20% 1360 cm$^{−1}$39% 1294 cm$^{−1}$12% 1053 cm$^{−1}$67% 1016 cm$^{−1}$41% 937 cm$^{−1}$35% 892 cm$^{−1}$41% 629 cm$^{−1}$31% 607 cm$^{−1}$49% 481 cm$^{−1}$36% 473 cm$^{−1}$52% |
| NMR ||
| Proton NMR | δ CDCl$_3$ 2.10 (3H), 11.42 (1H) |
| Carbon-13 NMR | δ CDCl$_3$ 20.8, 178.1 |
| Other NMR data | |
| MS ||
| Masses of main fragments | 60 (75%), 45 (90%), 43 (100%), 42 (13%), 15 (17%) |