🔬 Propionic anhydride (CAS 123-62-6) is one of the most versatile aliphatic acid anhydrides in industrial chemistry. A clear, colorless liquid with a sharp, vinegar-like odor, it serves as a powerful acylating and esterifying agent in the manufacture of pharmaceuticals, flavors and fragrances, cellulose esters, alkyd resins, and dyestuffs. If you are sourcing, specifying, or simply researching this compound, this guide brings together everything you need - and links out to detailed deep-dives on each topic.

Looking for verified specifications and a quote? See our propionic anhydride product page for grades, packaging, and COA.

✅ What Is Propionic Anhydride?

Propionic anhydride is the symmetrical acid anhydride of propionic (propanoic) acid, with the linear formula (CH₃CH₂CO)₂O and the molecular formula C₆H₁₀O₃. Structurally, two propionyl groups are joined by a single bridging oxygen, giving the molecule two reactive carbonyl centers that readily transfer a propionyl group to alcohols, amines, and other nucleophiles. This reactivity is exactly what makes it so useful as an acylating reagent.

💡 You will encounter this same compound under several names - they all refer to CAS 123-62-6:

• Propanoic anhydride (preferred IUPAC name)
• Propanoic acid anhydride / propionic acid anhydride
• Propionyl anhydride and the loosely-used propyl anhydride
• Propanoyl propanoate; propanoic acid, 1,1′-anhydride

📌 Quick tip: "propionic" and "propanoic" are interchangeable - the former is the traditional name, the latter the IUPAC name. They describe the identical molecule.

📊 Key Properties at a Glance

Data points are typical reference values; consult our SDS and COA for batch-specific figures. For an in-depth look at the molecule, see our guide on propionic anhydride structure and chemical properties.

🏭 What Is Propionic Anhydride Used For?

Because it efficiently introduces a propionyl group, propionic anhydride is a workhorse intermediate across several legitimate industries:

• 💊 Pharmaceutical intermediates - propionylation steps in active-ingredient synthesis.
• 🌸 Flavors & fragrances - production of propionate esters used in scent and taste formulations.
• 🧵 Cellulose esters - manufacture of cellulose acetate propionate (CAP) plastics and coatings.
• 🎨 Alkyd resins & dyestuffs - esterifying and modifying agent.
• 🧪 Organic synthesis - general acylating/esterifying reagent and dehydrating medium.

For a sector-by-sector breakdown with examples, read our dedicated article on propionic anhydride uses and industrial applications.

⚙️ How Is It Manufactured?

Industrially, propionic anhydride is produced by the carbonylation (Reppe) route, reacting ethylene with propionic acid and carbon monoxide over a catalyst, or by the ketene dehydration of propionic acid. Both deliver high-purity material for commercial grades. We cover the chemistry, purity grades, and quality control in how propionic anhydride is made.

⚠️ Safety, Hazards & Handling

Propionic anhydride is classified GHS Danger, H314 - it causes severe skin burns and eye damage, and reacts exothermically with water to release propionic acid. It is transported as UN 2496, Hazard Class 8 (corrosive). Handle with appropriate PPE (chemical goggles, gloves, face shield), use adequate ventilation, and store in tightly closed containers away from acids, bases, oxidizers, alcohols, and metals.

🦺 Always review the full Safety Data Sheet before handling. See our complete propionic anhydride safety, SDS & handling guide.

🔀 Related Anhydrides & Comparisons

Buyers often research mixed (crossed) anhydrides such as acetic propionic, formic propionic, butyric propionic, and benzoic propanoic anhydride - explained in our guide to mixed propionic anhydrides. If you are deciding between acylating agents, compare it head-to-head in

propionic anhydride vs acetic anhydride.

📋 Regulatory Status - Read This Before Buying

Propionic anhydride is a regulated chemical. In the United States it is a DEA List I chemical (controlled because it can be diverted as a precursor), and it is tracked internationally under chemical-control frameworks. Legitimate buyers must expect Know-Your-Customer (KYC) checks, end-use declarations, and import/export documentation. A compliant supplier protects both parties.

🛡️ Sinolook supplies propionic anhydride only for lawful industrial use, with full documentation support. Learn more in our regulatory & compliance guide (DEA List I, KYC & export controls).

💰 Price & Sourcing

Pricing is driven by propionic-acid/propylene feedstock, energy costs, grade, and compliance overhead. To understand the market, see propionic anhydride price & global market trends, and when you are ready to procure, follow our practical

guide to buying propionic anhydride in bulk from China.

❓ Frequently Asked Questions

🔹 Is propionic anhydride the same as propanoic anhydride?
Yes. "Propionic" (traditional) and "propanoic" (IUPAC) name the same compound, CAS 123-62-6. "Propionic acid anhydride" and "propionyl anhydride" are further synonyms for the identical molecule.

🔹 What is propionic anhydride used for?
Chiefly as an acylating/esterifying agent - in pharmaceutical intermediates, flavor and fragrance esters, cellulose acetate propionate, alkyd resins, and dyestuffs.

🔹 What is its chemical formula and molar mass?
The molecular formula is C₆H₁₀O₃ (linear (CH₃CH₂CO)₂O), with a molar mass of 130.14 g/mol.

🔹 Is propionic anhydride dangerous?
It is corrosive (GHS H314) and reacts with water. Use full PPE, ventilation, and proper storage; always consult the SDS first.

🔹 Is propionic anhydride a controlled chemical?
Yes - it is a DEA List I chemical in the U.S. and is regulated internationally as a precursor. Lawful purchase requires KYC and end-use documentation.

🔗 Explore the Full Series

📚 Authoritative references: PubChem CID 31263 ·

ECHA Substance Information.