Propanoic acid or C3H6O2 is a colorless liquid carboxylic acid with a pungent odor. It is used in the production of pharmaceuticals, herbicides, and food preservatives, among other things.
| IUPAC Name | Propanoic acid |
| Molecular Formula | C3H6O2 |
| CAS Number | 79-09-4 |
| Synonyms | Propionic acid, Methylacetic acid, Ethylformic acid, Propanylformic acid, Propionic acid solution, and more |
| InChI | InChI=1S/C3H6O2/c1-2-3(4)5/h2H2,1H3,(H,4,5) |
Propanoic acid Structure
Propanoic acid has a simple linear structure consisting of three carbon atoms, six hydrogen atoms, and two oxygen atoms. The carboxylic acid group (-COOH) is attached to the second carbon atom in the molecule. This structure allows propanoic acid to form strong hydrogen bonds with other propanoic acid molecules and with other compounds that have hydrogen bond acceptors or donors.
Propanoic acid boiling point
The boiling point of propanoic acid is 141.1 °C. This value is influenced by the intermolecular forces present in the compound. Propanoic acid has a relatively high boiling point compared to other simple carboxylic acids due to its ability to form strong hydrogen bonds. This property makes propanoic acid a useful solvent in organic chemistry.
Propanoic acid formula
The chemical formula of propanoic acid is C3H6O2. This formula represents the exact number and type of atoms in a single molecule of propanoic acid. The formula can be used to calculate the molar mass, molecular weight, and stoichiometric ratios in chemical reactions involving propanoic acid.
Propionic acid molar mass
Propionic acid has a molar mass of 74.08 g/mol. It is a simple organic carboxylic acid with three carbon atoms, six hydrogen atoms, and two oxygen atoms. The molar mass is an important parameter in chemistry as it is used to determine the amount of substance in a given sample. It is also used in stoichiometric calculations to determine the amount of reactant or product in a chemical reaction.
Propionic acid melting point
Propionic acid has a melting point of -20.8 °C. This low melting point is a result of the weak intermolecular forces present in the compound. Propionic acid is a liquid at room temperature and can easily solidify at low temperatures.
Propionic acid density g/ml
Propionic acid has a density of 0.99 g/mL at room temperature. This property is influenced by the molecular weight and packing density of the molecules in the compound. The density of propionic acid makes it less dense than water, allowing it to float on the surface of water.
Propionic acid molecular weight
The molecular weight of propionic acid is 74.08 g/mol. This value is calculated by summing the atomic weights of the constituent atoms in the molecule. The molecular weight of propionic acid is used to determine the molar mass and the number of moles of the compound in a given sample.
| Appearance | Colorless liquid |
| Specific Gravity | 0.99 g/mL |
| Color | Colorless |
| Odor | Pungent |
| Molar Mass | 74.08 g/mol |
| Density | 0.99 g/mL |
| Melting Point | -20.8 °C |
| Boiling Point | 141.1 °C |
| Flash Point | 60 °C |
| Water Solubility | Miscible |
| Solubility | Soluble in ethanol, ether, acetone |
| Vapour Pressure | 1.5 mmHg at 25 °C |
| Vapour Density | 2.5 (vs air) |
| pKa | 4.87 |
| pH | 2.8 (1 M solution) |
Note: The values provided in the table are approximate and may vary depending on the source of the data.
Propanoic acid Safety and Hazards
Improper handling of propanoic acid can pose safety and health hazards. This substance is corrosive and can cause severe skin and eye irritation, as well as respiratory problems if inhaled. Additionally, propanoic acid is flammable and can form explosive mixtures with air. To ensure safety, store it in a cool, dry, and well-ventilated area, away from sources of heat, sparks, or flames. When handling this substance, wear protective equipment such as gloves, goggles, and respiratory masks to prevent contact with skin and eyes or inhalation of vapors. Seek immediate medical attention in case of ingestion or contact with skin and eyes.
| Hazard Symbols | Corrosive (C) |
| Safety Description | S26-S36/37/39-S45 |
| UN Ids | UN 1848 |
| HS Code | 2915.90.10 |
| Hazard Class | 8 (Corrosive material) |
| Packing Group | III |
| Toxicity | LD50 (oral, rat) = 1.26 g/kg |
Propanoic acid Synthesis Methods
Propionic acid can be synthesized by several methods. One common method is the oxidation of propylene, which involves reacting propylene with air in the presence of a catalyst, typically a metal oxide, to form acrolein. The acrolein is then further oxidized to form acrylic acid, which is then converted to propionic acid through a decarboxylation reaction.
Another method involves the carboxylation of ethylene, which involves reacting ethylene with carbon dioxide and water in the presence of a catalyst, typically a metal salt or a palladium complex, to form acetaldehyde. The acetaldehyde is then oxidized to acetic acid, which is then converted to propanoic acid through a decarboxylation reaction.
A third method involves the hydrolysis of ethyl cyanide, which involves reacting ethyl cyanide with water in the presence of a strong acid or base to form propionic acid.
A fourth method involves the fermentation of carbohydrates, which involves the use of bacteria such as Propionibacterium freudenreichii to convert sugars into propionic acid. This method is commonly used in the food industry to produce propionic acid for use as a preservative.
Overall, these methods offer a variety of options for the synthesis of propionic acid, depending on the desired purity, yield, and environmental impact.
Propanoic acid Uses
- The food industry uses propanoic acid as a preservative to prevent bacterial and mold growth in baked goods, dairy products, and animal feed.
- Propionic acid serves as a chemical intermediate in the production of other chemicals, including esters used in the production of fragrances, flavors, and plastics.
- Propionic anhydride, produced from propanoic acid, is used as a solvent and reagent in organic synthesis.
- The pharmaceutical industry uses propanoic acid as a starting material in the synthesis of drugs such as ibuprofen, naproxen, and fenoprofen.
- Propionic acid is also utilized in the production of herbicides and insecticides.
- Cellulose acetate propionate, a coating for pharmaceuticals and a component of paints, varnishes, and coatings, is produced from propionic acid.
Overall, propionic acid has a diverse range of applications due to its antibacterial and preservative properties, as well as its versatility as a chemical intermediate.
Questions:
Which compound can be predicted to have chemical properties similar to propanoic acid (ch3ch2cooh)?
Propionic acid (CH3CH2COOH) predicts that compounds with a similar chemical structure will have comparable chemical properties. Butanoic acid (CH3CH2CH2COOH) is a compound with a similar structure to propionic acid, with an added methylene group in the carbon chain. This additional methylene group is expected to affect the molecule’s polarity and acidity, but both compounds have analogous characteristics such as being weak organic acids.
The food industry uses butanoic acid as a preservative, and it serves as a chemical intermediate in the production of esters, solvents, and pharmaceuticals, similar to propanoic acid. Butanoic acid can also substitute for propionic acid in certain applications as it has a close pKa value.
Is propanoic acid a strong acid?
Propanoic acid is a weak acid. It has a pKa value of around 4.87, indicating that it does not readily donate a proton to a base in a chemical reaction.
In comparison, strong acids such as hydrochloric acid (HCl) and sulfuric acid (H2SO4) have much lower pKa values and readily donate protons in chemical reactions. Despite being a weak acid, propionic acid is still useful in certain applications. Its weak acidity makes it suitable as a preservative in the food industry, as it is effective in inhibiting the growth of bacteria and fungi without affecting the taste or smell of food products.