FlavScents AInsights Entry for 2-methyl-2-pentenal (CAS: 623-36-9)

1. Identity & Chemical Information

• Common Name(s): 2-methyl-2-pentenal
• IUPAC Name: 2-methylpent-2-enal
• CAS Number: 623-36-9
• FEMA Number: Not available
• Other Identifiers: Not available
• Molecular Formula: C6H10O
• Molecular Weight: 98.15 g/mol
• Functional Groups and Structure–Odor Relevance: 2-methyl-2-pentenal is an α,β-unsaturated aldehyde. The presence of the aldehyde group contributes to its characteristic pungent odor, which is often associated with green and citrus-like notes. The unsaturation in the carbon chain can influence its reactivity and volatility, impacting its sensory profile.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

2-methyl-2-pentenal is characterized by a sharp, pungent odor with green, citrus, and slightly fruity notes. It is known for its high intensity and diffusion, making it a potent impact note in formulations. The odor threshold is not clearly reported, but its strong scent suggests it is effective at low concentrations. Typically, it serves as an impact note or a modifier in both flavor and fragrance applications, providing a fresh, green character.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

2-methyl-2-pentenal is not commonly found in nature but can be formed through synthetic pathways. It may be produced via the aldol condensation of acetaldehyde and propionaldehyde, followed by dehydration. Its presence in natural products is limited, and it is primarily used in synthetic formulations. As such, it does not typically qualify for "natural flavor" or "natural fragrance" designations.

Citation hooks: FlavScents; food chemistry literature; EFSA/JECFA monographs

4. Use in Flavors

2-methyl-2-pentenal is used in flavor formulations to impart green, citrus, and fruity notes. It is commonly found in citrus and fruity flavor categories, enhancing the freshness and complexity of the profile. Typical use levels in finished food or beverage products range from 0.1 to 5 ppm, depending on the desired intensity and the matrix of the product. It is relatively stable under acidic conditions but may degrade under high heat or oxidative environments.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance applications, 2-methyl-2-pentenal is used in various product types, including personal care products and household cleaners. It contributes to the top notes, providing a fresh, green, and citrusy character. Typical concentration ranges are from trace amounts to 0.5%, depending on the formulation and desired effect. Its volatility makes it suitable for top note applications, where it can enhance the initial impact of the fragrance.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: Not explicitly listed as FEMA GRAS; usage should comply with general safety standards.
• European Union: Not specifically listed under Regulation (EC) No 1334/2008; usage should align with general flavoring regulations.
• United Kingdom: Follows EU regulations post-Brexit; no specific divergence reported.
• Asia: Limited specific data; general compliance with local flavor and fragrance regulations is advised.
• Latin America: No specific data; adherence to regional standards such as those in Brazil and MERCOSUR is recommended.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

• Oral Exposure: Data not found for specific ADI or MSDI values. General safety practices suggest using minimal effective concentrations to ensure safety.
• Dermal Exposure: Limited data on irritation or sensitization; formulators should conduct patch tests and adhere to IFRA guidelines.
• Inhalation Exposure: Volatile nature suggests potential for inhalation exposure; occupational safety measures should be in place to minimize risks.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

2-methyl-2-pentenal is valued for its ability to impart a fresh, green, and citrusy character to both flavors and fragrances. It synergizes well with other citrus and green notes, enhancing the overall freshness of the formulation. Common pitfalls include overuse, leading to an overpowering scent, and instability under certain conditions. It is often under-used in complex formulations where its impact can be subtly integrated.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on 2-methyl-2-pentenal is well-established in terms of its chemical identity and sensory profile. However, there are gaps in specific regulatory approvals and detailed toxicological data. Industry practices often rely on general safety guidelines and empirical evidence from similar compounds.

Citation hooks: FlavScents

QA Check

• All required sections 1–9 are present
• "Citation hooks:" line is present under each section
• Flavor section includes ppm ranges
• Toxicology section covers oral, dermal, inhalation
• Regulatory section mentions US, EU, UK, Asia, Latin America
• If complex natural material: includes section 5a (not applicable here)

About FlavScents AInsights (Disclosure)
FlavScents AInsights integrates information from authoritative government, scientific, academic, and industry sources to provide applied, exposure-aware insight into flavor and fragrance materials. Data are drawn from regulatory bodies, expert safety panels, peer-reviewed literature, public chemical databases, and long-standing professional practice within the flavor and fragrance community. Where explicit published values exist, they are reported directly; where gaps remain, AInsights reflects widely accepted industry-typical practice derived from convergent sensory behavior, historical commercial use, regulatory non-objection, and expert consensus. All such information is clearly labeled to distinguish documented data from professional guidance or informed estimation, with the goal of offering transparent, practical, and scientifically responsible context for researchers, formulators, and regulatory specialists. This section is generated using advanced computational language modeling to synthesize and structure information from established scientific and regulatory knowledge bases, with the intent of supporting—not replacing—expert review and judgment.

Generated 2026-08-12 14:56:52 GMT (p2)