BUTYL P-HYDROXYBENZOATE

CAS: 94-26-8 FLAVORING AGENT OR ADJUVANT

BUTYL P-HYDROXYBENZOATE is a synthetic ester of p-hydroxybenzoic acid used as a flavoring agent or adjuvant in foods and evaluated internationally by regulators for use as a food additive.

What It Is

BUTYL P-HYDROXYBENZOATE is a synthetic organic compound classified in food additive contexts as a flavoring agent or adjuvant. Chemically, it is an ester of p-hydroxybenzoic acid with n-butanol, fitting within the broader class of compounds known as parabens, which are esters of para-hydroxybenzoic acid with various alcohols. The compound has the CAS Registry Number 94-26-8 and appears in scientific databases and regulatory evaluations under multiple synonyms, including butylparaben, butyl 4-hydroxybenzoate, benzoic acid, 4-hydroxy-, butyl ester, benzoic acid, p-hydroxy-, butyl ester, and 4-(butoxycarbonyl)phenol. Parabens like butyl p-hydroxybenzoate have historically been used for their functional properties in foods, cosmetics, and pharmaceuticals. In its pure form, butyl p-hydroxybenzoate is a white crystalline powder that is slightly soluble in water but dissolves more readily in organic solvents. Its use in food technology is primarily due to its ability to contribute to flavor profiles or act in conjunction with other flavoring substances. As a flavoring agent or adjuvant, the substance typically does not provide nutritive value itself but enhances or supports the desired sensory profile of food products. This classification aligns with regulatory frameworks in jurisdictions such as the United States, where synthetic flavoring substances are regulated as part of food additive provisions. The compound is recognized under regulatory listing codes that govern its permitted use conditions and manufacturing practice requirements.

How It Is Made

The manufacture of butyl p-hydroxybenzoate involves a classic esterification reaction between p-hydroxybenzoic acid and n-butanol in the presence of an acid catalyst. In typical industrial practice, an acid such as sulfuric acid is used to catalyze the reaction, facilitating the formation of the ester bond between the carboxylic acid group of p-hydroxybenzoic acid and the alcohol group of n-butanol. After the initial reaction phase, the mixture is usually subjected to purification steps such as crystallization, solvent removal, and filtration to yield a high-purity crystalline product suitable for use in food-related applications. This synthetic route is consistent with the preparation of many parabens, which are formed by esterifying the parent p-hydroxybenzoic acid with different alcohols to yield compounds with varying chain lengths and properties. Butyl p-hydroxybenzoate is one of the longer-chain parabens, with a four-carbon alcohol moiety, which affects its functional properties compared with shorter-chain analogs. The esterification method used is robust and scalable, making it suitable for industrial production. Quality control measures during manufacturing typically involve checks on melting point, purity, residual solvent levels, and compliance with defined chemical specifications. Because the compound is used in food and food-related products, manufacturing processes are designed to meet food-grade standards and to minimize the presence of impurities that could affect safety or sensory characteristics. In regulated settings, the substance is often produced and handled according to principles such as good manufacturing practice (GMP), which involve minimizing contaminants and ensuring that the production environment conforms to hygiene and quality standards appropriate for food additives. The purity and identity of the compound are verified through analytical methods to ensure compliance with regulatory standards for food flavoring agents.

Why It Is Used In Food

Butyl p-hydroxybenzoate is used in food primarily for its functional role as a flavoring agent or adjuvant. Flavoring agents are substances added to foods to impart, modify, or enhance flavor. In many food formulations, such agents are used at very low levels to achieve a desired sensory profile or to complement natural or artificial flavor systems. As an adjuvant, butyl p-hydroxybenzoate may support the overall flavor system without itself being a dominant taste contributor. The technical logic behind using this compound in food stems from its chemical structure and sensory characteristics. Compounds in the paraben family are typically odorless or have very faint organoleptic qualities at the concentrations used for flavoring purposes. This makes them useful when a formulation requires structural stability and flavor enhancement without introducing strong extraneous flavors. The compound’s chemical stability under typical food processing conditions, such as moderate heat or pH variation, further supports its use in a range of food products. In addition to flavor-related functions, derivatives of p-hydroxybenzoic acid have historically been used in preservative roles in other industries due to antimicrobial properties. While in many food systems preservatives are governed by separate regulatory provisions, the broader expertise with paraben chemistry informs how flavoring agents like butyl p-hydroxybenzoate are understood by food scientists. Its inclusion in regulatory listings for synthetic flavoring substances reflects the technical assessment that, when used under defined conditions aligned with good manufacturing practice, the compound supports targeted flavoring objectives without compromising food quality. Manufacturers often select flavoring agents such as butyl p-hydroxybenzoate based on their compatibility with other ingredients and their ability to withstand processing conditions. The compound’s functional role is usually clearly defined within formulation documents, with specific concentration guidelines to deliver the intended sensory outcome while respecting regulatory limits.

Adi Example Calculation

Because butyl p-hydroxybenzoate does not have a numeric ADI established in the referenced JECFA evaluation, a hypothetical numeric example calculation cannot be constructed using a defined ADI value. In general, if a numeric ADI were available, an illustrative calculation would involve multiplying a person’s body weight by the ADI to estimate the total amount of a substance that could theoretically be consumed daily without appreciable risk. For example, for a hypothetical ADI of X mg per kg body weight per day and a body weight of Y kg, the acceptable intake would be calculated as X times Y. In the case of butyl p-hydroxybenzoate, the regulatory evaluation concluded no safety concern at current levels of intake when used as a flavoring agent, rather than assigning a specific numeric intake threshold. As a result, the focus remains on ensuring that food formulations incorporating this compound adhere to good manufacturing practices and typical usage patterns, rather than on a numerical comparison against an established ADI.

Safety And Health Research

Regulatory authorities and scientific committees assess compounds like butyl p-hydroxybenzoate by reviewing available toxicological and exposure data to determine whether their use in food poses any safety concerns. The international evaluation conducted by JECFA concluded that there is no safety concern at current levels of intake when used as a flavoring agent, which reflects a comprehensive review of available studies at the time of evaluation. This type of assessment considers a range of toxicological endpoints including acute toxicity, genotoxicity, chronic effects, reproductive and developmental toxicity, and exposure estimates based on usage levels. Studies relevant to butyl p-hydroxybenzoate encompass a broad array of research on parabens, a family of compounds with similar chemical structures. Toxicological research often evaluates how these compounds are absorbed, metabolized, and excreted in animal models, as well as any potential impacts on organ systems. Regulatory evaluations integrate these research findings to assess whether typical exposure through intended food use is likely to present risk. For butyl p-hydroxybenzoate, the JECFA evaluation concluded no safety concern when used at levels appropriate for a flavoring agent. This type of conclusion typically encompasses a margin of safety based on toxicological data compared with estimated dietary exposure. In evaluating safety, regulators also take into account mechanisms of action, including any potential for the compound to interact with biological systems. Parabens have been the subject of research into endocrine activity due to structural similarities with biologically active phenolic compounds. However, the regulatory conclusion of no safety concern at current intake levels reflects a judgment that such theoretical concerns do not translate into demonstrable adverse effects at the exposure levels anticipated from flavoring use. The absence of specific numeric ADI values in the regulatory documentation reflects the qualitative nature of the conclusion rather than a defined intake limit. Ongoing research in toxicology and exposure science continues to inform how regulators view compounds like butyl p-hydroxybenzoate. Scientific developments, including studies on metabolism, potential biological interactions, and human exposure patterns, may be considered in future evaluations by regulatory authorities. The current evidence base supports the safe use of this compound in food flavoring under defined conditions, consistent with the available regulatory evaluations.

Regulatory Status Worldwide

The regulatory status of butyl p-hydroxybenzoate varies across jurisdictions but is generally framed within established food additive provisions. In the United States, synthetic flavoring substances and adjuvants are governed by 21 CFR 172.515, which outlines the conditions under which such substances may be safely used in food. This section of the Code of Federal Regulations specifies that synthetic flavoring substances are used in the minimum quantity necessary for their intended effect and consistent with good manufacturing practice, and it enumerates a list of specific compounds and classes of compounds that fall within this category. While the published regulation lists many substances, the inclusion of butyl p-hydroxybenzoate in regulatory reference materials suggests its recognition under this framework for permitted flavoring use with appropriate conditions (21 CFR 172.515). However, explicit numerical use limits or concentration thresholds for this specific compound are not delineated in the publicly accessible portion of the regulation, and therefore it is not possible to assign a definitive quantitative allowable level without additional authoritative documentation. Accordingly, the field "approved" is null in the regulatory safety section with an explanatory note that explicit approval and use conditions for this specific compound are not directly verifiable from currently d text in CFR documentation. At the international level, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) evaluated butyl p-hydroxybenzoate and concluded in its 2002 evaluation that there is "no safety concern at current levels of intake when used as a flavouring agent." This conclusion reflects a qualitative assessment rather than a specific numeric acceptable daily intake (ADI), and the specification for the compound was later withdrawn, indicating that while evaluated, it may not have an established specification in the current monographs. The JECFA evaluation year and detailed numeric data are not explicitly shown on the d database entry, and thus numeric values related to ADI or year cannot be verified. In the regulatory safety section, the jecfa year and numeric ADI fields remain null with notes indicating that the evaluation concluded no safety concern without numeric values. Other regulatory bodies may have additional evaluations for the compound, particularly in contexts outside food flavoring. For example, cosmetic regulatory frameworks often include parabens like butyl p-hydroxybenzoate with specific use conditions and concentration limits. These contexts, however, are separate from food additive regulations and are not the primary focus of this ingredient reference document. Regulatory status worldwide thus reflects a combination of formal evaluations, country-specific provisions, and general guidance on safe usage under defined conditions.

Taste And Functional Properties

Despite its technical classification as a flavoring agent or adjuvant, butyl p-hydroxybenzoate typically has minimal intrinsic taste at the levels used in food formulations. This means it does not contribute a strong identifiable flavor on its own but can influence the overall flavor profile when used in conjunction with other flavoring substances. In sensory studies, compounds of this type are often described as having faint phenolic or neutral sensory characteristics, which is consistent with its chemical structure as an ester of p-hydroxybenzoic acid. Functionally, the compound exhibits certain chemical stability features that are valuable in food processing. Esters like butyl p-hydroxybenzoate tend to resist degradation under mild heat and can remain intact across a range of pH conditions encountered in food systems. This stability supports consistent flavor performance from production through storage. Its moderate solubility in organic solvents and limited water solubility influence how it is incorporated into different food matrices. In emulsified systems or those with alcohol components, the compound may disperse more readily than in highly aqueous formulations, necessitating formulation strategies that ensure even distribution. From a functional perspective, flavoring agents do not typically serve nutritive purposes but are selected to help achieve desired sensory outcomes. Butyl p-hydroxybenzoate’s role is thus to assist in achieving a balanced and nuanced flavor profile when paired with other flavor components. The compound’s chemical behavior, including its reactivity and partitioning characteristics, informs how it interacts with other ingredients. Flavor chemists often consider such functional properties when designing formulations for products that require subtle enhancements without altering the base taste. Overall, the compound’s sensory neutrality, stability under processing conditions, and compatibility with other flavoring ingredients make it a useful component in flavor systems. These properties are leveraged to meet specific product objectives, particularly in complex formulations where precise control over flavor perception is critical.

Acceptable Daily Intake Explained

An Acceptable Daily Intake (ADI) is a regulatory concept used by food safety authorities to express the amount of a substance that can be ingested daily over a lifetime without appreciable health risk. ADIs are typically derived from toxicological studies in animals or humans and incorporate safety factors to account for uncertainties in extrapolating from experimental systems to human exposure. They are not recommendations for daily consumption but rather benchmarks for regulatory assessment and risk management. For butyl p-hydroxybenzoate, the JECFA evaluation concluded that there is no safety concern at current intake levels when used as a flavoring agent, which effectively means that the compound does not have an established numeric ADI in the referenced evaluation documentation. This outcome suggests that exposure from intended food use is sufficiently low that it does not warrant a defined intake limit based on the evidence available at the time of assessment. Instead, the regulatory assessment focuses on ensuring that usage conditions and levels align with good manufacturing practices and realistic exposure considerations. In regulatory contexts where an ADI is established, it serves as a quantitative benchmark against which estimated daily intake from all sources can be compared. For compounds without a numeric ADI but with a conclusion of no safety concern, the focus is on ensuring that usage patterns do not lead to exposure levels that exceed those considered safe based on toxicological evidence. The absence of a numeric ADI in the regulatory documentation for butyl p-hydroxybenzoate should not be interpreted as a lack of safety evaluation; rather, it reflects that the evaluators did not identify a level of concern requiring a defined intake limit.

Comparison With Similar Additives

Butyl p-hydroxybenzoate belongs to the family of parabens, which also includes related compounds such as methylparaben, ethylparaben, and propylparaben. These compounds share a common structural motif as esters of p-hydroxybenzoic acid with alcohol moieties of varying chain lengths. The differences in chain length influence their physicochemical properties, such as solubility, partitioning behavior, and antimicrobial activity. For example, shorter-chain parabens like methylparaben are more water-soluble, while longer-chain analogs like butyl p-hydroxybenzoate are less water-soluble and may exhibit different distribution in food matrices. In comparative usage, methylparaben and ethylparaben have historically been more common as preservatives in a range of consumer products due to their broad-spectrum antimicrobial activity and relatively favorable solubility profiles. Propylparaben occupies an intermediate position with respect to chain length and functional properties. Butyl p-hydroxybenzoate, with a longer butyl chain, is often used where stability and specific functional roles, such as flavoring adjuvant behavior, are desired. The sensory contributions of these related compounds are generally minimal at typical usage levels, which is why they are often used in combination with other flavoring substances or preservatives to achieve desired formulation goals. Regulatory treatment of these related additives also varies by jurisdiction and specific application. In the FDA’s regulatory framework, synthetic flavoring substances are listed under provisions like 21 CFR 172.515, which enumerates permissible flavoring agents. In cosmetic regulations, parabens are often subject to concentration limits based on safety assessments. In international contexts, safety evaluations by bodies like JECFA have considered these compounds both individually and as a class in terms of toxicity and exposure. Comparisons with other flavoring agents outside the paraben family, such as natural esters or volatile aroma compounds, highlight differences in functional roles. Many natural flavoring agents contribute direct sensory characteristics, whereas butyl p-hydroxybenzoate and similar compounds are selected for subtle enhancement or support of flavor profiles. The choice among flavoring agents depends on multiple factors including regulatory acceptance, sensory objectives, and compatibility with other formulation components.

Common Food Applications Narrative

Butyl p-hydroxybenzoate finds application in a variety of food products where flavor enhancement or support is needed without introducing strong sensory notes of its own. As a flavoring agent or adjuvant, it is used in formulations designed to achieve nuanced taste profiles, especially in products with layered or delicate flavors. Food scientists may include such compounds in the design of beverages, confections, sauces, baked goods, and other processed foods where balancing flavor elements is essential. In beverages such as soft drinks or ready-to-drink formulations, flavoring agents like butyl p-hydroxybenzoate can be part of a broader blend that delivers a consistent and desirable sensory experience. In baked goods and confectionery, the compound can assist in rounding out flavor systems, particularly those incorporating multiple natural or artificial flavor components. In sauces, dressings, and condiments, where complex flavors are engineered to meet specific consumer preferences, such agents play supporting roles that help enhance overall palatability. The use of this compound in these contexts is guided by detailed formulation protocols and regulatory requirements that ensure safe and effective incorporation. Product developers consider not only sensory outcomes but also interactions with other ingredients, processing conditions, and the expected shelf life of the final product. Because flavoring agents are typically used in very small quantities relative to the overall formulation, their primary impact is on taste perception rather than on texture or nutritional profile. Food manufacturers also rely on established regulatory frameworks to determine permissible use conditions for compounds like butyl p-hydroxybenzoate. These frameworks define how flavoring agents can be used in different product categories and under what conditions, such as adherence to good manufacturing practice, to ensure that consumer exposure remains within acceptable boundaries. In practice, the selection of flavoring agents is part of a broader strategy to deliver products that meet consumer expectations for taste, quality, and consistency across production batches. Ultimately, the inclusion of butyl p-hydroxybenzoate in specific food applications reflects both technical considerations related to flavor formulation and regulatory compliance with established food additive provisions.

Safety & Regulations

FDA

  • Notes: The referenced regulation section covers synthetic flavoring substances generally but does not explicitly list use conditions for this compound in the d text.
  • Regulation: 21 CFR 172.515

EFSA

  • Notes: No specific EFSA ADI value was verified from available authoritative links.

JECFA

  • Notes: JECFA concluded no safety concern at current intake levels but did not provide a numeric ADI in the d database entry.

Sources

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