# Propyl 4-tert-butylphenylacetate

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**Safety rating:** UNKNOWN
**CAS number:** 92729-55-0
**Category:** flavoring
**FDA GRAS:** no
**Adverse events (FDA AERS):** 0
**FDA recalls:** 0
**Last updated:** 2026-04-04

## Summary

Propyl 4-tert-butylphenylacetate is a synthetic flavoring compound used to impart fruity and aromatic notes in food products. It functions as a flavoring agent or adjuvant to enhance taste and aroma profiles in various food applications.

## Regulatory status

| Country | Status |
| --- | --- |
| United States | approved |
| European Union | not_evaluated |
| United Kingdom | approved |
| Canada | approved |
| Australia | approved |
| Japan | approved |
| South Korea | approved |
| Brazil | approved |
| China | approved |
| India | approved |

## Detailed analysis

## What is Propyl 4-tert-butylphenylacetate?

Propyl 4-tert-butylphenylacetate (CAS Number: 92729-55-0) is a synthetic organic compound belonging to the class of phenylacetate esters. It is a volatile flavoring ingredient designed to provide fruity, floral, and aromatic characteristics to food and beverage products. The compound consists of a phenylacetate core structure with a tert-butyl substitution, combined with a propyl ester group, creating a molecule with specific sensory properties valued in the flavor industry.

## Common Uses

As a flavoring agent, propyl 4-tert-butylphenylacetate is used in very small quantities in various food categories where fruity or aromatic flavor enhancement is desired. These applications typically include beverages, confectionery, baked goods, dairy products, and other processed foods. Like most synthetic flavoring compounds, it is used at concentrations measured in parts per million (ppm), meaning only tiny amounts are needed to achieve the desired flavor effect. The compound is particularly valued for its ability to contribute complex fruity notes that enhance overall flavor profiles without imparting off-flavors.

## Safety Assessment

Propyl 4-tert-butylphenylacetate has not received FDA GRAS (Generally Recognized As Safe) status, which means it has not been formally evaluated through the GRAS notification process. However, this classification should not be interpreted as indicating the substance is unsafe. Rather, it reflects that formal GRAS documentation has not been submitted to or accepted by the FDA for this particular compound.

The FDA adverse events database contains zero reported adverse events associated with this additive, and there have been no product recalls linked to propyl 4-tert-butylphenylacetate. This absence of reported safety incidents, combined with its use at extremely low concentrations typical of flavoring agents, suggests a favorable safety profile in practice.

As a synthetic ester compound, propyl 4-tert-butylphenylacetate would be subject to metabolic degradation in the body similar to other ester-based compounds. The propyl ester linkage would likely be hydrolyzed during digestion, breaking the compound into its constituent parts, which the body can then metabolize through established pathways.

## Regulatory Status

The regulatory status of propyl 4-tert-butylphenylacetate varies by jurisdiction. In the United States, while it lacks GRAS status, it may be used under FDA regulations if it complies with applicable food additive regulations or if its use is otherwise permitted. The European Union maintains its own approved list of flavoring substances; regulatory status in EU member states should be verified independently.

Manufacturers seeking to use this flavoring compound must comply with all applicable regulations in their respective markets, including restrictions on maximum use levels, labeling requirements, and documentation of safety. The absence of GRAS status means that individual manufacturers or flavor suppliers may need to maintain additional safety data or documentation to support its use.

## Key Studies

Scientific literature specifically dedicated to propyl 4-tert-butylphenylacetate is limited, which is typical for specialized synthetic flavoring compounds used in minute quantities. The compound's safety assessment would generally rely on: (1) structural similarity to other approved flavoring esters, (2) the absence of adverse event reports despite years of potential use, (3) the ultra-low concentrations at which it is employed, and (4) general principles of ester metabolism and toxicology applicable to its chemical class.

Flavor ingredient manufacturers typically conduct or reference safety studies including acute toxicity testing and composition purity analysis for compounds in this category, though such data may not be publicly available. Researchers and regulatory bodies often apply read-across approaches, evaluating similar approved compounds to inform safety assessments of structurally similar flavoring agents.

## Sources

- FDA Substances Added to Food (CFSAN)
- OpenFDA Adverse Event Reporting System (AERS)
- OpenFDA Food Recalls
- EFSA OpenFoodTox
- EU Food Additive Portal

## Citation

Additive Facts. "Propyl 4-tert-butylphenylacetate — Safety, regulation, and evidence." https://additivefacts.com/additives/propyl-4-tert-butylphenylacetate. Accessed 2026-05-20.