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Send EmailAcetylpyrazine, Acetyl Pyrazine, Methyl Pyrazinyl Ketone, 22047-25-2
Acetylpyrazine (2-Acetylpyrazine)
CAS Number: 22047-25-2
Chemical Formula: C₆H₆N₂O
Molecular Weight: 122.12 g/mol
FEMA Number: 3126
UNII: GR391IBU5C
Synonyms: 2-Acetylpyrazine, Ethanone (1-pyrazinyl), Methyl pyrazinyl ketone, Pyrazin-1-ylethan-1-one, Acetyl Pyrazine
1. CHEMICAL IDENTITY
| Parameter | Information |
|---|---|
| Product Name | Acetylpyrazine |
| IUPAC Name | 1-(Pyrazin-2-yl)ethan-1-one |
| CAS Number | 22047-25-2 |
| Chemical Formula | C₆H₆N₂O |
| Molecular Weight | 122.12 g/mol |
| FEMA Number | 3126 |
| UNII | GR391IBU5C |
| Chemical Class | Pyrazine derivative, Aromatic ketone |
| Synonyms | 2-Acetylpyrazine, Ethanone (1-pyrazinyl), Methyl pyrazinyl ketone, Pyrazin-1-ylethan-1-one, Acetyl Pyrazine |
2. PHYSICAL PROPERTIES
| Parameter | Value |
|---|---|
| Physical State (20°C) | Solid |
| Color | Light yellow to brownish |
| Appearance | Crystalline powder or flakes |
| Odor | Roasted, nutty, popcorn-like, corn-like |
| Taste | Nutty, roasted, popcorn |
| Melting Point | 75 – 78 °C (167-172°F) |
| Boiling Point | 212.9 °C (415°F) at 760 mmHg |
| Density (25°C) | 1.1075 – 1.136 g/cm³ |
| Refractive Index (20°C) | 1.518 – 1.535 |
| Vapor Pressure (25°C) | ~0.5 mmHg |
| Flash Point | 84.4 °C (184°F) (closed cup) |
| Log P (Partition Coefficient) | 0.20 – 0.68 |
| Polar Surface Area (PSA) | 42.85 Ų |
3. THERMODYNAMIC PROPERTIES
| Parameter | Value |
|---|---|
| Autoignition Temperature | Not determined |
| Specific Heat Capacity | ~1.5 J/g·K (estimated) |
| Heat of Vaporization | ~50 kJ/mol (estimated) |
4. SOLUBILITY PROPERTIES
| Solvent | Solubility |
|---|---|
| Water | Slightly soluble |
| Ethanol | Soluble |
| Propylene Glycol | Soluble |
| Vegetable Oil | Soluble |
| Triglycerides | Soluble |
| Most Organic Solvents | Soluble |
5. CHEMICAL PROPERTIES AND REACTIVITY
| Parameter | Information |
|---|---|
| Functional Groups | Ketone (C=O) + Pyrazine ring (N-heterocycle) |
| pKa | ~1.5 (pyrazine nitrogen protonation) |
| Reactivity | Reacts with nucleophiles at carbonyl carbon |
| Stability | Stable under normal storage conditions (dark, dry, cool) |
| Incompatible Materials | Strong oxidizing agents, strong bases |
| Shelf Life | 24 months (2 years) under proper storage |
6. TYPICAL PRODUCT SPECIFICATIONS
| Parameter | Specification | Test Method |
|---|---|---|
| Purity | ≥ 98.0% (typically 99.0-99.5%) | GC / HPLC |
| Melting Point | 75 – 78 °C | USP <741> |
| Loss on Drying | ≤ 0.5% | Gravimetric |
| Residue on Ignition | ≤ 0.1% | Gravimetric |
| Heavy Metals (as Pb) | ≤ 10 ppm | AAS/ICP |
| Appearance | Light yellow to brownish crystalline powder | Visual |
| Odor | Popcorn, nutty, roasted | Organoleptic |
7. AROMA PROFILE AND FLAVOR CHARACTERISTICS
| Parameter | Description |
|---|---|
| Primary Aroma | Popcorn, roasted corn |
| Secondary Notes | Nutty (hazelnut, peanut), roasted, bread crust, chocolate |
| Flavor Intensity | Very strong (requires dilution for use) |
| Threshold in Water | ~10-50 ppb (very low – potent aroma compound) |
| Typical Use Concentration | 0.1 – 10 ppm (parts per million) in final food product |
Sensory Description: Acetylpyrazine has a powerful, characteristic "popcorn" aroma with roasted, nutty, and corn-like notes. It is one of the key aroma compounds in roasted foods, popcorn, bread crust, and cocoa.
8. PRODUCTION PROCESS
| Method | Description |
|---|---|
| Ester Condensation | Ethyl pyrazine-2-carboxylate (EtO₂C-pyrazine) undergoes condensation |
| Dehydration + Grignard | Pyrazinamide → 2-cyanopyrazine → Reaction with methyl magnesium bromide (Grignard reagent) |
| Direct Synthesis | Pyrazine + Acetyl chloride or acetic anhydride with Friedel-Crafts catalyst |
Simplified Reaction (Grignard route):
2-Cyanopyrazine + CH₃MgBr → Acetylpyrazine (after hydrolysis)
9. APPLICATIONS – FOOD AND BEVERAGE FLAVOR
| Application | Function | Typical Use Level |
|---|---|---|
| Savory Snacks (Chips, Pretzels) | Popcorn, roasted corn, nutty flavor | 1 – 10 ppm |
| Bakery Products (Bread, Crackers) | Bread crust, roasted grain notes | 0.5 – 5 ppm |
| Chocolate and Cocoa Products | Enhances cocoa, roasted notes | 1 – 5 ppm |
| Nut Flavored Products | Hazelnut, peanut, roasted nut notes | 1 – 10 ppm |
| Barbecue Sauces and Marinades | Smoky, roasted, meaty notes | 1 – 10 ppm |
| Coffee and Tea | Roasted coffee, tea notes | 0.5 – 5 ppm |
| Meat Flavors (Beef, Chicken) | Roasted, cooked meat notes | 1 – 10 ppm |
| Soy Sauce and Savory Sauces | Fermented, roasted notes | 1 – 5 ppm |
Key Use: Acetylpyrazine is the primary aroma compound responsible for the characteristic "popcorn" smell and taste.
10. APPLICATIONS – TOBACCO FLAVOR
| Application | Function | Typical Use Level |
|---|---|---|
| Cigarettes | Enhances roasted, nutty, sweet notes | Low ppm range |
| Smokeless Tobacco | Flavor enhancement | Low ppm range |
| Heated Tobacco Products | Roasted, tobacco-like notes | Low ppm range |
Tobacco Application: Enhances the roasted, nutty, and sweet flavor profile of tobacco products.
11. APPLICATIONS – COSMETICS AND FRAGRANCE
| Application | Function | Typical Use Level |
|---|---|---|
| Soaps | Warm, natural, roasted base note | 0.01 – 0.1% |
| Perfumes | Adds warmth, nutty, gourmand notes | Trace amounts |
| Body Care Products | Natural, warm scent | 0.005 – 0.05% |
| Home Fragrance (Candles) | Roasted, comforting notes | Low ppm range |
12. APPLICATIONS – PHARMACEUTICAL
| Application | Description |
|---|---|
| Anticancer Drug Synthesis | Intermediate in the synthesis of anticancer agents |
| Pharmaceutical Intermediate | Building block for various drug candidates |
| Folic Acid Synthesis | Intermediate in folic acid production |
| Polycyclic Compound Production | Building block for polycyclic aromatic compounds |
13. APPLICATIONS – RESEARCH AND ORGANIC SYNTHESIS
| Application | Description |
|---|---|
| Antimicrobial Research | Some pyrazine derivatives active against Pseudomonas aeruginosa |
| Heterocyclic Synthesis | Building block for more complex heterocyclic compounds |
| Medicinal Chemistry | Scaffold for drug discovery programs |
14. COMPARISON WITH SIMILAR AROMA COMPOUNDS
| Compound | CAS | Aroma Profile | Odor Threshold | Primary Use |
|---|---|---|---|---|
| Acetylpyrazine | 22047-25-2 | Popcorn, roasted corn, nutty | 10-50 ppb | Popcorn, snack flavors |
| 2-Acetylthiazole | 24295-03-2 | Roasted, corn-like | Very low | Popcorn, meat flavors |
| 2-Acetylpyrroline | 1006-41-5 | Aromatic rice, bread crust | Extremely low (~0.02 ppb) | Basmati rice, bread crust |
| 2-Acetylfuran | 1192-62-7 | Sweet, roasted nut | 100-200 ppb | Nutty, coffee flavors |
| 2-Acetylpyridine | 1122-62-9 | Sourish, roasted | Moderate | Minor flavor component |
15. FEMA (FLAVOR AND EXTRACT MANUFACTURERS ASSOCIATION) STATUS
| Parameter | Information |
|---|---|
| FEMA Number | 3126 |
| GRAS Status | Generally Recognized as Safe for use as a flavor ingredient |
| Typical Use Level in Food | 1 – 10 ppm (0.0001 – 0.001%) |
| JECFA Status | Evaluated and approved |
16. REGULATORY STATUS
| Region/Agency | Status |
|---|---|
| FDA (USA) | GRAS for use as a flavoring agent (FEMA 3126) |
| EU | Approved for use as a flavoring substance |
| EFSA | Evaluated and considered safe at intended use levels |
| JECFA | Evaluated; no safety concerns at current intake levels |
| Türkiye (TGK) | Approved for use as a flavoring agent |
| FEMA | Listed as GRAS (FEMA 3126) |
17. ALTERNATIVE NAMES AND TRADE NAMES
| Name | Usage Context |
|---|---|
| Popcorn Aroma | Common/household name |
| Corn Husk Odor | Descriptive |
| Roasted Nut Essence | Flavor industry |
| Chocolate Top Note | Flavor industry |
| Barbecue Aroma | Flavor industry |
| 2-Acetylpyrazine | Technical/scientific |
| Pyrazinyl methyl ketone | Technical |
18. SAFETY AND TOXICOLOGICAL PROFILE
| Parameter | Value |
|---|---|
| Acute oral toxicity (rat, LD₅₀) | ~1,000 – 2,000 mg/kg (moderate toxicity) |
| Acute dermal toxicity (rabbit, LD₅₀) | >2,000 mg/kg |
| Skin irritation | May cause mild irritation |
| Eye irritation | May cause mild irritation |
| Skin sensitization | Not a known sensitizer |
| Carcinogenicity | Not classified as carcinogenic |
| Mutagenicity | Negative in standard tests |
| Inhalation (dust) | May cause respiratory irritation |
GHS Classification (Acetylpyrazine – powder form):
| Hazard Class | Description |
|---|---|
| Not classified | Generally not classified as hazardous for transport (non-dangerous goods) |
Safety Precautions:
-
Avoid dust generation
-
Use with adequate ventilation
-
Avoid contact with skin and eyes
-
Wash hands after handling
19. STORAGE AND HANDLING
| Parameter | Requirement |
|---|---|
| Storage Temperature | 2-8°C (refrigerated preferred) or 15-25°C (room temperature, dark) |
| Container | Tightly sealed (glass, HDPE, aluminum) |
| Light Protection | Protect from light (dark storage recommended) |
| Humidity | Low humidity (hygroscopic) |
| Incompatible Materials | Strong oxidizing agents, strong bases |
| Shelf Life | 24 months (2 years) under proper storage |
| Special Precautions | Store in dark, dry, cool environment. Heat and light may cause degradation. |
20. SUMMARY AND CRITICAL INFORMATION
Description: Acetylpyrazine (2-Acetylpyrazine, CAS 22047-25-2) is a pyrazine derivative and aromatic ketone with the molecular formula C₆H₆N₂O. It is a light yellow to brownish crystalline powder or flakes with a melting point of 75-78°C. Acetylpyrazine is most famous for its powerful, characteristic "popcorn" aroma, along with roasted, nutty, and bread-crust notes. It is a key aroma compound in popcorn, roasted coffee, chocolate, nuts, and bread crust.
Key Advantages:
-
Very potent aroma compound (low threshold: 10-50 ppb in water)
-
Characteristic popcorn, roasted corn flavor (unique)
-
Heat-stable (suitable for baking, extrusion, frying)
-
FEMA GRAS (FEMA 3126) – approved for food use
-
Versatile – used in snacks, bakery, chocolate, tobacco, fragrance
Key Limitations/Precautions:
-
Moderate acute oral toxicity (LD₅₀ ~1,000-2,000 mg/kg)
-
May cause mild skin/eye irritation
-
Light-sensitive (store in dark)
-
Low water solubility (requires alcohol or oil-based carriers)
Major Applications Summary:
| Sector | Primary Uses |
|---|---|
| Food and Beverage | Savory snacks, bakery, chocolate, coffee, barbecue sauces, meat flavors |
| Tobacco | Flavor enhancement (roasted, nutty notes) |
| Cosmetics/Fragrance | Soaps, perfumes (warm, natural base notes) |
| Pharmaceutical | Intermediate for anticancer drugs, folic acid synthesis |
| Research | Antimicrobial studies, heterocyclic synthesis |
Typical Use Levels in Food:
| Application | Concentration |
|---|---|
| Savory snacks | 1 – 10 ppm |
| Bakery products | 0.5 – 5 ppm |
| Chocolate/cocoa | 1 – 5 ppm |
| Barbecue sauces | 1 – 10 ppm |
Comparison to Similar Aroma Compounds:
| Compound | Aroma | Use |
|---|---|---|
| Acetylpyrazine | Popcorn, roasted corn | Snacks, popcorn flavor |
| 2-Acetylthiazole | Roasted, corn-like | Meaty, savory flavors |
| 2-Acetylpyrroline | Aromatic rice, bread crust | Basmati rice, bread flavors |
Safety Summary:
-
Moderate acute oral toxicity (LD₅₀ ~1,000-2,000 mg/kg)
-
Not classified as hazardous for transport
-
Handle with standard laboratory precautions
-
Avoid dust generation and skin contact
Storage: Tightly sealed, dark, dry, cool (2-8°C preferred); 24-month shelf life.
Conclusion: Acetylpyrazine is one of the most important pyrazine-based aroma compounds used by the food and flavor industry. Its powerful, characteristic "popcorn" aroma makes it essential for savory snacks, popcorn flavorings, roasted nuts, chocolate, coffee, and barbecue sauces. It is also used in tobacco flavoring, fragrance compositions (soaps, perfumes), and as a pharmaceutical intermediate for anticancer drug synthesis. FEMA GRAS (FEMA 3126) and approved by major regulatory bodies (FDA, EU, EFSA, JECFA), acetylpyrazine is a safe and effective flavor ingredient when used at recommended levels (1-10 ppm in food products). Its low odor threshold (10-50 ppb) means only trace amounts are needed to achieve its characteristic roasted, popcorn-like flavor profile.
