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Propanoic acid

Skeletal structure of propanoic acid with terminal carbon

Propanoic acid is an organic compound with formula C2H5COOH.

Table of contents
  1. 1Names
  2. 2Formulae and structures
  3. 3Properties
  4. 4Constituents
  5. 5Thermodynamic properties
  6. 6Solubility
  7. 7Hazards
  8. 8Preparations
  9. 9Chemical reactions
  10. 10References
  11. 11Related substances
  12. 12Related categories

Names

List of substance names

Nomenclature
Name
Typical name
Propanoic acid
Compositional nomenclature
Hydrogen propanoate
Substitutive nomenclature
Propanoic acid
★Preferred IUPAC name
Ethanecarboxylic acid
Other names
Propionic acid
Hydrogen propionate
Propylic acid
Methylacetic acid
Carboxyethane

Formulae and structures

List of formulae

Formula name
Formula
Typical formula
C2H5COOH
Molecular formula
C2H5COOH
Empirical formula
C3H6O2
Condensed formula
CH3CH2COOH
Structural formula
Chemical structure of propanoic acid
Structural formula with no C–H bond
Chemical structure of propanoic acid with no C-H bond
Skeletal formula
Skeletal structure of propanoic acid
Skeletal formula with terminal carbon
Skeletal structure of propanoic acid with terminal carbon
Lewis structure
Lewis structure of propanoic acid
Colored Lewis structure
Colored Lewis structure of propanoic acid

Properties

List of substance properties

Item
Value
Name
Propanoic acid
Formula
C2H5COOH
Appearance
Colorless liquid
Odor
Pungent, rancid odor[1]
Slight, pungent, unpleasant, rancid odor[2]
Pungent odor[3]
Strong, rancid odor[4]
Molar mass
74.079 g/mol
Density
0.99336 g/cm3[2]
Liquid, 20°C
0.9934 g/cm3[5]
Liquid, 20°C
0.9882 g/cm3[6]
Liquid, 25°C
Melting point
−21.5 °C[2]
−20.5 °C[5][6]
Boiling point
141.1 °C[2]
at 101.3 kPa
141.1 °C[5]
141.5 °C[6]
Flash point
58 °C[2]
52 °C[5]
Refractive index
1.3848[2]
25°C
1.3809[5][6]
20°C

Constituents

Constituent atoms

AtomNameOxidation stateNumber
CCarbon−31
CCarbon−21
HHydrogen+16
CCarbon+31
OOxygen−22

Ratio of atoms

AtomAtomic weightNumberAtomic ratioWeight ratio
C12.011327.27%48.64%
H1.008654.55%8.16%
O15.999218.18%43.19%
CHOAtomic ratio
CHOWeight ratio

Thermodynamic properties

Phase transition properties

Item
Value
Enthalpy of fusion
10.66 kJ · mol−1[5][6]
at −21.5°C
Enthalpy of vaporization
32.3 kJ · mol−1[5]
at 141.1°C
Enthalpy of vaporization at 25°C
32.1 kJ · mol−1[5]
32.14 kJ · mol−1[6]
at 141.5°C
Enthalpy of other transition

Standard thermodynamic properties

State
Standard enthalpy
of formation
ΔfH°
kJ · mol−1
Standard Gibbs
energy of
formation
ΔfG°
kJ · mol−1
Standard
molar entropy
S°
J · K−1 · mol−1
Standard molar
heat capacity at
constant pressure
Cp°
J · K−1 · mol−1
Liquid−510.7[5]−383.5[5]191.0[5]152.8[5]

Solubility

Qualitative solubility

Reactive
Miscible
Very soluble
Soluble
Slightly soluble
CHCl3[6]Trichloromethane
Very slightly soluble
Insoluble

Hazards

GHS label[7]

Physical hazards[7]

Health hazards[7]

Environmental hazards[7]

Preparations

Reaction of alcohol, chromium vi compound, and hydrogen ion

Oxidation of alcohol can yield propanoic acid.

Reaction of 1-Propanol, chromium(VI) oxide, and hydrogen ion
3C3H7OH1-Propanol + 4CrO3Chromium(VI) oxide + 12H+Hydrogen ion
3C2H5COOHPropanoic acid + 4Cr3+Chromium(III) ion + 9H2OWater
Reaction of 1-Propanol, dichromic acid, and hydrogen ion
3C3H7OH1-Propanol + 2H2Cr2O7Dichromic acid + 12H+Hydrogen ion
3C2H5COOHPropanoic acid + 4Cr3+Chromium(III) ion + 11H2OWater
Reaction of 1-Propanol, chromic acid, and hydrogen ion
3C3H7OH1-Propanol + 4H2CrO4Chromic acid + 12H+Hydrogen ion
3C2H5COOHPropanoic acid + 4Cr3+Chromium(III) ion + 13H2OWater
Reaction of 1-Propanol, sodium dichromate, and hydrogen ion
3C3H7OH1-Propanol + 2Na2Cr2O7Sodium dichromate + 16H+Hydrogen ion
3C2H5COOHPropanoic acid + 4Cr3+Chromium(III) ion + 4Na+Sodium ion + 11H2OWater
Reaction of 1-Propanol, sodium chromate, and hydrogen ion
3C3H7OH1-Propanol + 4Na2CrO4Sodium chromate + 20H+Hydrogen ion
3C2H5COOHPropanoic acid + 4Cr3+Chromium(III) ion + 8Na+Sodium ion + 13H2OWater

Chemical reactions

Electrolytic dissociation

Electrolytic dissociation of propanoic acid yields hydrogen ion and propanoate ion.

Electrolytic dissociation of propanoic acid
C2H5COOHPropanoic acid
H+Hydrogen ion + C2H5COOPropanoate ion

References

List of references

  1. 1
    George A. Burdock (2009)
    Fenaroli's Handbook of Flavor Ingredients, 6th edition
    CRC Press

  2. 2
  3. 3
    Fisher Scientific
    Fisher Scientific: Lab Equipment and Lab Supplies
    Thermo Fisher Scientific

  4. 4
    Office of Response and Restoration
    CAMEO Chemicals
    National Oceanic and Atmospheric Administration

  5. 5
  6. 6
  7. 7