Propionic anhydride is a chemical compound used in the synthesis of various pharmaceuticals, dyes, and pesticides. It acts as an acylation reagent in organic reactions.
| IUPAC Name | Propanoic anhydride |
| Molecular Formula | C6H10O3 |
| CAS Number | 123-62-6 |
| Synonyms | Propionic acid anhydride, Propionyl anhydride, Ethylformic anhydride, Propanoyl oxide |
| InChI | InChI=1S/C6H10O3/c1-2-5-8-6(7)9-3-4-8/h1-4H2 |
Propionic Anhydride Properties
Propionic Anhydride Formula
The formula for propionyl anhydride is C6H10O3. It represents the chemical composition of this compound, showing the types and number of atoms present in each molecule.
Propionic Anhydride Molar Mass
The molar mass of propionyl anhydride is the sum of the atomic masses of all its constituent atoms. With a molecular formula of C6H10O3, its molar mass is calculated to be approximately 130.14 g/mol.
Propionic Anhydride Boiling Point
Propionyl anhydride has a boiling point of around 169-170°C (336-338°F). This temperature indicates the point at which the compound transitions from a liquid to a gas under standard atmospheric pressure.
Propionic Anhydride Melting Point
The melting point of propionyl anhydride is approximately -42 to -41°C (-44 to -42°F). This is the temperature at which the compound changes from a solid to a liquid state.
Propionic Anhydride Density g/mL
Propionyl anhydride has a density of about 1.08 g/mL. This value represents the mass of the compound per unit volume, indicating its heaviness or compactness.
Propionic Anhydride Molecular Weight
The molecular weight of propionyl anhydride is calculated to be around 126.11 g/mol. It is the sum of the atomic weights of all the atoms in a single molecule of the compound.
Propionic Anhydride Structure
The structure of propionyl anhydride consists of a central carbon atom bonded to two oxygen atoms and two additional carbon atoms. It is formed through the condensation of two molecules of propionic acid.
Propionic Anhydride Solubility
Propionyl anhydride is sparingly soluble in water. It exhibits better solubility in organic solvents like ether, benzene, and chloroform. The compound’s solubility characteristics are important factors to consider in various applications and chemical reactions.
| Appearance | Colorless liquid |
| Specific Gravity | 1.08 g/mL |
| Color | N/A |
| Odor | Pungent, acrid |
| Molar Mass | 130.14 g/mol |
| Density | 1.08 g/mL |
| Melting Point | -42 to -41°C (-44 to -42°F) |
| Boiling Point | 169-170°C (336-338°F) |
| Flash Point | 64°C (147°F) |
| Water Solubility | Sparingly soluble |
| Solubility | Soluble in organic solvents like ether, benzene, and chloroform |
| Vapor Pressure | 1.4 mmHg at 25°C |
| Vapor Density | 4.4 (air = 1) |
| pKa | 4.85 |
| pH | Not applicable |
Propionic Anhydride Safety and Hazards
Propionyl anhydride poses several safety hazards and should be handled with caution. It is irritating to the eyes, skin, and respiratory system. Direct contact may cause burns or chemical sensitization. Inhalation of vapors can lead to respiratory tract irritation and difficulty breathing. The compound is flammable and can form explosive mixtures with air. Adequate ventilation and protective equipment, such as gloves and goggles, should be used when working with propionyl anhydride. In case of ingestion, medical attention should be sought immediately. Proper storage and handling procedures must be followed to minimize the risks associated with this chemical.
| Hazard Symbols | Corrosive (C) |
| Safety Description | Keep away from heat, sparks, open flames, and hot surfaces. Avoid breathing vapor or mist. Wear protective gloves, eye/face protection, and protective clothing. |
| UN IDs | UN 2924 |
| HS Code | 29159010 |
| Hazard Class | 8 (Corrosive substances) |
| Packing Group | II |
| Toxicity | Harmful if swallowed or inhaled. Causes severe skin burns and eye damage. |
Propionic Anhydride Synthesis Methods
Multiple methods enable the synthesis of propionyl anhydride.
One common approach is the reaction between propanoic acid and acetic anhydride. In this method, propanoic acid acts as the reactant, reacting with acetic anhydride in the presence of a catalyst such as sulfuric acid or p-toluenesulfonic acid. The reaction proceeds through an esterification process, resulting in the formation of propionyl anhydride and acetic acid as a byproduct.
Another method involves the reaction of propanoic acid with phthalic anhydride. This reaction takes place under reflux conditions in the presence of a catalyst, such as concentrated sulfuric acid or zinc chloride. The reaction produces propionyl anhydride and phthalic acid as a byproduct.
An alternative synthesis route utilizes the reaction between propionic acid and acetyl chloride. This reaction occurs under controlled conditions with the presence of a Lewis acid catalyst, such as aluminum chloride or zinc chloride. The resulting reaction yields propionyl anhydride and hydrochloric acid.
These methods enable the production of propionyl anhydride on a laboratory or industrial scale. It is crucial to remember that individuals must follow proper safety precautions and handling procedures when synthesizing propionyl anhydride due to the hazardous nature of the reactants and catalysts involved.
Propionic Anhydride Uses
Propionyl anhydride finds utility in various applications due to its versatile properties. Some key uses include:
- Pharmaceutical industry: It serves as a crucial intermediate in the synthesis of pharmaceutical compounds, including analgesics, antibiotics, and anti-inflammatory drugs.
- Textile Industry: The textile industry uses propionyl anhydride for textile processing, specifically in manufacturing synthetic fibers.
- Agrochemicals: Propionyl anhydride plays a vital role in producing pesticides and herbicides, aiding in crop protection and pest control.
- Polymer industry: Propionyl anhydride acts as an acylating agent, participating in the synthesis of polymers, resins, and coatings.
- Chemical research: It serves as a reagent in various organic reactions, enabling the formation of esters and other derivatives.
- Solvent applications: Propionyl anhydride finds use as a solvent for cellulose derivatives, resins, and waxes.
- Fragrance and flavor industry: It contributes to the creation of fragrances and flavors, enhancing the scent and taste profiles of various products.
- Dye Manufacturing: Manufacturers employ propionyl anhydride in dye production, particularly for synthesizing acid dyes and reactive dyes.
- Laboratory reagent: It serves as a valuable reagent in laboratory settings for organic synthesis and analysis.
These applications highlight the significance of propionyl anhydride across multiple industries, contributing to the development of pharmaceuticals, agrochemicals, polymers, and more.
Questions:
Q: How fast is the hydrolysis of propionic anhydride in acid?
A: The hydrolysis of propionyl anhydride in acid is relatively fast, with the reaction occurring at a reasonable rate.
Q: Is propionic anhydride an irritant?
A: Yes, propionyl anhydride is an irritant, causing irritation to the eyes, skin, and respiratory system upon direct contact.
Q: What is the structure of acetic propionic anhydride?
A: Acetic propionyl anhydride has a structure consisting of two acyl groups attached to a central oxygen atom.
Q: How to make propionic anhydride?
A: Propionyl anhydride can be synthesized by the reaction of propionic acid with an appropriate acylating agent, such as acetic anhydride or acetyl chloride.
Q: What is the product of the following reaction: propionic anhydride?
A: The product of the reaction involving propionyl anhydride depends on the specific reaction conditions and the reagents involved.
Q: How fast is the hydrolysis of propionic anhydride in acid?
A: The hydrolysis of propionyl anhydride in acid occurs at a relatively rapid rate.
Q: How to draw the line-angle formula for acetic propionic anhydride?
A: The line-angle formula for acetic propionyl anhydride can be drawn by representing the atoms as vertices and connecting them with lines according to the bonding arrangement.
Q: Is propionic anhydride polar?
A: Yes, propionyl anhydride is polar due to the presence of polar bonds and the asymmetrical distribution of charge within the molecule.