FlavScents AInsights Entry for Methyl Ethyl Ketone (CAS: 78-93-3)

1. Identity & Chemical Information

• Common Name(s): Methyl Ethyl Ketone, MEK
• IUPAC Name: Butan-2-one
• CAS Number: 78-93-3
• FEMA Number: Not applicable
• Other Identifiers: FL Number: 07.039
• Molecular Formula: C4H8O
• Molecular Weight: 72.11 g/mol

Methyl ethyl ketone (MEK) is a simple aliphatic ketone characterized by a carbonyl group (C=O) flanked by two alkyl groups. Its structure contributes to its solvent properties and volatility, which are relevant to its odor profile. The presence of the carbonyl group is crucial for its reactivity and interaction with other compounds in formulations.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Methyl ethyl ketone is known for its sharp, sweet, and acetone-like odor. It is often described as having a pungent, ether-like aroma with moderate intensity and high diffusion. While not typically used for its flavor, its odor threshold is relatively low, making it detectable even at minimal concentrations. In sensory applications, MEK can serve as a background note, providing a solvent-like character that enhances the perception of other aromatic compounds.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Methyl ethyl ketone is not commonly found in nature but can be produced through the oxidation of 2-butanol. It is not typically associated with "natural flavor" or "natural fragrance" designations due to its synthetic origins. However, it may be present in trace amounts in some fermented products as a byproduct of microbial metabolism.

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

4. Use in Flavors

MEK is not widely used as a flavoring agent due to its solvent-like odor and potential safety concerns. When used, it serves primarily as a processing aid or solvent in flavor formulations rather than as a direct flavor component. Typical use levels in food are minimal, often below 10 ppm, primarily to ensure the stability and solubility of other flavor compounds. Its stability is generally good under neutral pH and ambient temperatures, but it can degrade under acidic conditions or high heat.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance applications, methyl ethyl ketone is valued for its volatility and ability to enhance the diffusion of other fragrance components. It is used in various fragrance families, including floral and citrus, as a solvent or diluent. Typical concentrations in fragrance formulations range from trace amounts to about 1%, depending on the desired volatility and evaporation rate. MEK contributes primarily to the top notes due to its high volatility.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: MEK is not listed as a FEMA GRAS substance for flavor use. It is regulated by the FDA as a food additive with specific limitations.
• European Union: Under Regulation (EC) No 1334/2008, MEK is not approved as a flavoring substance. It is subject to REACH regulations for industrial use.
• United Kingdom: Post-Brexit, the UK aligns with EU regulations regarding MEK's use in flavors and fragrances.
• Asia: In Japan and China, MEK is regulated primarily for industrial applications, with limited use in consumer products.
• Latin America: Regulations vary, but MEK is generally restricted to industrial applications, with specific guidelines for safe handling.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

Methyl ethyl ketone poses potential safety concerns primarily through inhalation and dermal exposure. It is a known irritant and can cause respiratory and skin irritation upon contact. Inhalation exposure is a concern in occupational settings, where adequate ventilation is necessary. For oral exposure, MEK is not typically used in flavors, and thus, ADI or MSDI values are not established. Dermal exposure in fragrance applications should be minimized to prevent irritation, and formulations should comply with IFRA guidelines.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

MEK is valued for its solvent properties, which enhance the solubility and stability of other compounds in formulations. It is often used in combination with other solvents to achieve desired evaporation rates and diffusion characteristics. Formulators should be cautious of its volatility and potential for irritation, ensuring that concentrations remain within safe limits. Overuse can lead to overpowering solvent notes, while underuse may result in inadequate solubility of key ingredients.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on methyl ethyl ketone is well-established, particularly regarding its chemical properties and industrial applications. However, its use in flavors and fragrances is less documented, with industry practices often guiding its application. Regulatory guidelines are clear, but variations exist across regions, necessitating careful compliance checks.

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 2026-03-26 07:33:21 GMT (p2)