BUTYL PHENYLACETATE

CAS: 122-43-0 FLAVORING AGENT OR ADJUVANT

Butyl phenylacetate is a synthetic esteric flavoring agent with a pleasant floral and honey-like taste and odor used in food and fragrance applications.

What It Is

Butyl phenylacetate is a synthetic chemical compound classified as a flavoring agent or adjuvant used in foods and beverages to impart or enhance aroma and taste. Its chemical identity is reflected in the CAS Registry Number 122-43-0, and it appears in flavor-related regulatory lists used by agencies such as the U.S. Food and Drug Administration (FDA) under 21 CFR 172.515. It belongs chemically to the class of aromatic esters formed from phenylacetic acid and butanol, and it is known for distinct sensory attributes that include sweet, floral, honey-like and mild chocolate notes at typical usage levels as a flavor ingredient. Its synonyms also include butyl alpha-toluate, benzeneacetic acid, butyl ester, and butyl phenylethanoate, among others. The compound has been evaluated by international safety bodies and the Flavor and Extract Manufacturers Association (FEMA) with specific identifier FEMA 2209, which is commonly used in the flavor industry for cross-reference of flavoring agents.

How It Is Made

Butyl phenylacetate is produced through an esterification reaction between phenylacetic acid and butanol under appropriate catalytic conditions. In a typical synthetic route, the carboxylic acid functional group of phenylacetic acid reacts with the hydroxyl group of butanol in the presence of an acid catalyst to form the ester functional group characteristic of butyl phenylacetate. This general process is widely used in the chemical industry to prepare esters for fragrance and flavor applications due to the relative simplicity and controllability of the reaction. After synthesis, the product may be purified by distillation or solvent washing to achieve a high degree of purity suitable for flavor use. The manufacturing practice emphasizes controlling reaction conditions and removing residual reactants to meet flavoring industry specifications for food-grade esters.

Why It Is Used In Food

The use of butyl phenylacetate in food products centers on its sensory impact as a flavoring agent. In formulations, it contributes complex aroma notes that can enhance or modify overall flavor profiles of foods and beverages. Because it produces floral, honey-like, and subtle sweet nuances, it is particularly useful in applications where such sensory attributes are desired, such as in fruit-flavored products, confections, dairy and cream notes, and specialty beverages. In addition to its direct sensory effect, butyl phenylacetate may be used in combination with other flavoring chemicals to create more balanced or nuanced flavor blends, as part of the broader toolbox of flavor technology. Its inclusion in regulatory flavoring lists enables food developers to incorporate it under defined conditions, generally at minimal levels required to achieve the intended taste effect.

Adi Example Calculation

An illustrative example of how an ADI concept might be applied (for educational purposes and not specific to this compound’s regulatory status) would involve comparing estimated daily intake with the ADI. For illustration only, if a hypothetical ADI were set at a value X mg per kg body weight per day, a 70 kg adult’s acceptable intake would be X times 70. Real intake from typical flavoring use is generally orders of magnitude lower, given the small quantities used in foods. In the case of butyl phenylacetate, regulatory evaluations have concluded no safety concern at current intake levels, which means that theoretical intake estimates based on typical usage concentrations fall well below thresholds of toxicological concern. Therefore, in practice, specific numerical calculations are unnecessary for regulatory compliance when safety evaluations indicate no concern.

Safety And Health Research

Safety evaluations of butyl phenylacetate have been conducted by recognized expert bodies assessing its toxicological profile in the context of use as a food flavoring agent. The JECFA evaluation concluded that at current levels of intake typical for flavoring use, there is no safety concern, reflecting an assessment of available data on toxicity and exposure. Toxicological research for ester-type flavoring substances generally includes studies on acute toxicity, subchronic exposure, genotoxicity, and metabolic fate. For butyl phenylacetate, available data indicate it has a relatively low acute toxicity profile, consistent with many aliphatic and aromatic esters used as flavoring agents. Safety assessments also consider exposure levels relative to sensory use levels in foods, addressing potential consumer exposure through dietary intake. Regulatory agencies and expert panels periodically review such data as part of ongoing safety monitoring and evaluation frameworks for food additives.

Regulatory Status Worldwide

In the United States, butyl phenylacetate is associated with the FDA’s list of synthetic flavoring substances and adjuvants permitted for direct addition to food under 21 CFR 172.515, which outlines conditions for safe use of synthetic flavoring substances when used in good manufacturing practice. This regulation reflects the recognition of many synthetic flavoring substances, including butyl phenylacetate, as acceptable for their intended use under defined conditions. Internationally, it has been evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), which concluded that it presents no safety concern at current levels of intake when used as a flavoring agent, based on available toxicological data. Regulatory frameworks in other regions, such as the European Union, allow flavoring substances subject to flavoring legislation and specifications consistent with safety assessments and good practice. The compound’s inclusion in flavoring inventories like FEMA 2209 further reflects its recognized status within industry and regulatory contexts.

Taste And Functional Properties

Butyl phenylacetate exhibits organoleptic properties described as floral, honey-like and mildly sweet with subtle chocolate nuances at typical use concentrations, making it effective for imparting desirable sensory notes. Its solubility characteristics align with other ester-type flavoring agents — it is generally soluble in oils and organic solvents but has limited water solubility, which affects how it is incorporated into different food matrices. The compound’s stability under typical food processing conditions such as mixing and ambient temperature storage supports its utility in flavor applications, though like many esters it may hydrolyze under strongly acidic or high temperature environments. In practical applications, flavor chemists consider both odor and taste thresholds because butyl phenylacetate’s sensory perception can be strong even at low concentrations, and its contributions can be amplified or muted depending on the overall blend and food matrix. These functional properties help food formulators leverage specific sensory profiles while controlling overall flavor balance.

Acceptable Daily Intake Explained

The concept of an acceptable daily intake (ADI) is used by food safety authorities to express the amount of a substance that can be ingested daily over a lifetime without appreciable health risk, based on toxicological data and conservative safety factors. For flavoring substances like butyl phenylacetate, JECFA determined that use at typical levels does not raise safety concerns, a conclusion that effectively indicates that the intake from food use is well below any threshold of toxicological concern identified in available studies. It is important to note that ADIs, when established, are not recommended intakes but rather safety benchmarks to help regulators and industry ensure safe conditions of use over time. In the case of butyl phenylacetate, the conclusion of no concern at current intake levels obviates the need for a numerical ADI value from JECFA, meaning that consumer exposure under normal flavoring use scenarios is considered acceptable.

Comparison With Similar Additives

Butyl phenylacetate can be compared to other aromatic ester flavoring agents such as ethyl phenylacetate and benzyl acetate. Like butyl phenylacetate, ethyl phenylacetate has a fruity, floral aroma and is used to enhance fruit and floral notes in food flavors. Benzyl acetate similarly contributes sweet floral notes and is often used in fruit and tropical flavor profiles. Compared to shorter-chain esters, these aromatic esters provide more nuanced and complex sensory contributions due to the interaction of the phenyl ring with the ester group, which affects volatility and odor perception. Formulators often choose among these esters based on the specific sensory target, balancing intensity, volatility, and harmony within a flavor blend.

Common Food Applications Narrative

Butyl phenylacetate finds use in a variety of commercial and culinary product categories where enhanced flavor character is desirable. Its floral and honey-like taste profile makes it suitable for use in fruit-flavored foods, confectionery items, dairy and cream enhancements, beverages, baked goods, and certain savory blends that benefit from layered aroma complexity. In beverage applications, small amounts can contribute to overall sensory perception without dominating the base flavor, especially in non-alcoholic drinks and flavored waters. In confectionary and sweet goods, butyl phenylacetate can add depth to candy, chocolate, and cream-based products. Its aromatic properties are also leveraged in fruit preparations and dessert fillings to round out and balance the sweetness of sugars. Across these applications, butyl phenylacetate is typically used in minimal quantities required to achieve the desired taste effect, in line with principles of flavor formulation and regulatory use conditions.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 172.515

EFSA

  • Notes: EFSA authorization and numerical ADI not specifically identified in available sources

JECFA

  • Notes: JECFA concluded no safety concern at current intake levels without a numeric ADI

Sources

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