4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL
4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL is a synthetic antioxidant phenolic compound permitted for specific uses in food and food-contact applications under US federal regulations with defined conditions of use.
What It Is
4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL is a synthetic antioxidant additive belonging to the class of hindered phenolic compounds. Chemically identified by the Chemical Abstracts Service (CAS) under the number 88-26-6, this compound also appears under a variety of synonyms in scientific and regulatory contexts. These synonyms include, among others, butylated hydroxymethylphenol, 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, and Ionox 100 antioxidant identifiers. The defining structural feature of this class of compounds is the phenolic ring substituted at positions 2,6 with bulky tert-butyl groups and a hydroxymethyl side chain at position 4. The presence of these bulky substituents around the phenolic moiety provides steric hindrance that stabilizes the phenolic radical formed during oxidation processes, conferring antioxidant activity. In food science and technology, this substance functions primarily as an antioxidant, meaning it helps delay oxidative degradation in susceptible systems. Oxidation is a chemical process that affects fats, oils, and fat-containing foods, leading to rancidity, off-flavors, and loss of quality over time. By interrupting the chain reactions that propagate lipid oxidation, antioxidants like 4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL help maintain sensory and nutritional attributes of products. While structurally related to other phenolic antioxidants used in industry, such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA), this compound has distinct functional groups and regulatory designations. Beyond its role in food, hindered phenolic antioxidants such as this may also be encountered in polymer stabilization and material science, where they help protect plastics and elastomers from oxidative degradation during processing and use. However, the present article focuses on its identity and role as a regulated food additive when used under specified conditions in authorized jurisdictions.
How It Is Made
The production of 4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL involves organic synthesis routes typical of substituted phenolic compounds. At an industrial or laboratory scale, synthesis begins with phenolic precursors that are chemically modified to introduce the requisite tert-butyl substituents at the 2 and 6 positions of the aromatic ring and a hydroxymethyl functional group at the 4 position. These synthetic steps often involve electrophilic aromatic substitution reactions under controlled conditions. After synthesis, the product is subjected to purification techniques such as recrystallization or chromatographic separation to achieve the desired purity level consistent with regulatory or technical specifications required for antioxidant applications. During manufacturing, quality control assessments are essential to confirm the identity, purity, and stability of the product. Typical analytical techniques used in this context include nuclear magnetic resonance (NMR) spectroscopy, high-performance liquid chromatography (HPLC), and melting point determination. The purified compound typically appears as a solid powder with a characteristic melting point range that reflects consistent crystalline form and appropriate structural integrity. Manufacturers categorize the product according to performance parameters, ensuring it meets industry standards for antioxidant efficacy. Impurities and by-products from synthesis are carefully monitored because they can affect performance or regulatory compliance. For food-related applications, additional specifications may be imposed to limit levels of residual solvents, heavy metals, or other contaminants. These specifications are established based on safety and performance data and are aligned with regulatory criteria where applicable. While detailed proprietary synthesis pathways vary between producers, the overarching chemical manufacturing process combines well-understood organic transformations with rigorous analytical assessment to yield a stable antioxidant suitable for its intended uses.
Why It Is Used In Food
4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL is incorporated into certain food formulations and food-contact materials principally because of its antioxidant properties. Antioxidants serve to inhibit or slow the oxidative deterioration of lipids and fat-associated compounds, which can compromise food quality, extend shelf life, and protect sensory attributes. In foods where oxidative rancidity is a concern, such as oils, fats, and fat-containing processed foods, antioxidants help maintain desirable flavor, color, and nutritional value by mitigating the formation of off-flavors and off-odors over time. The mechanism by which this compound functions centers on its ability to donate hydrogen atoms to free radicals generated during the oxidative process. When reactive oxygen species or other radicals attack lipid molecules, a chain reaction can propagate, leading to successive degradation of fats. Antioxidants like 4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL intervene by stabilizing these radicals, thus interrupting the chain reaction and reducing the rate of oxidation. This functional role is particularly valuable in products with high fat content or where storage conditions may expose fats to oxidizing influences. In addition to direct food applications, this antioxidant may also be used in polymeric or packaging materials that come into contact with food. In these contexts, the compound helps protect the material from oxidative stress during processing and use, minimizing degradation that could otherwise affect barrier properties or material integrity. When used in accordance with regulatory conditions, such applications contribute indirectly to food quality and safety by preserving the properties of packaging components that come into contact with food.
Adi Example Calculation
Because a formal acceptable daily intake (ADI) was not allocated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) for 4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL, there is no numeric ADI value to use in illustrative calculations. In contrast to compounds with established numeric ADIs, where one might calculate a theoretical daily intake for a given body weight, the lack of an ADI means that such a calculation cannot be made. For additive compounds with established ADIs, illustratively, if an ADI were, for example, X mg/kg body weight, a person weighing Y kg might have a theoretical safe intake of (X mg/kg bw/day) times Y kg. However, because there is no allocated numeric ADI for this specific compound according to the d JECFA documentation, this explanatory example cannot be applied directly here. Regulatory frameworks instead rely on defined conditions of use that limit how much of the antioxidant may be present in food or food-contact materials. Those use limits are intended to keep exposure at levels that regulators consider acceptable based on available data. As such, consumers and formulators refer to regulatory conditions rather than hypothetical intake calculations tied to an ADI number.
Safety And Health Research
Assessing the safety of food additives such as 4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL involves examining toxicological data, exposure estimates, and potential hazard endpoints. Regulatory agencies like the FDA consider submitted data on acute toxicity, genotoxicity, and long-term studies to determine whether a compound can be authorized for specified uses. The absence of an allocated acceptable daily intake (ADI) from the Joint FAO/WHO Expert Committee on Food Additives (JECFA) indicates that a comprehensive risk assessment including chronic exposure evaluations and detailed toxicological profiling was not completed or not considered necessary at the time of review. This does not imply a finding of harm but rather that global bodies did not establish a numerical threshold for lifetime intake during their evaluations. Toxicological studies often begin with acute exposure assessments in animal models to identify dose levels associated with adverse effects. Additional chronic and subchronic studies may explore endpoints such as organ toxicity, reproductive effects, and carcinogenicity. For compounds authorized under specific regulatory conditions, risk management includes limiting exposure by defining use levels and application categories. For 4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL, regulatory texts specify conditions that constrain how much antioxidant can be present in foods or food-contact materials, thus controlling potential exposure. Beyond regulated limits, safety research also considers absorption, distribution, metabolism, and excretion (ADME) characteristics. Phenolic antioxidants often undergo metabolic transformation in the body, and understanding these pathways helps regulators gauge potential systemic exposure. While comprehensive peer-reviewed human clinical data may be limited, animal and in vitro studies combined with regulatory evaluations form the basis for authorized uses. Continued monitoring of scientific literature and safety databases informs potential updates to regulatory decisions, reflecting evolving evidence on food additive safety.
Regulatory Status Worldwide
The regulatory framework for 4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL varies by jurisdiction and application type. In the United States, the Food and Drug Administration (FDA) recognizes this compound in Title 21 of the Code of Federal Regulations. Specifically, 21 CFR 172.150 authorizes its use as a direct food additive under defined conditions, including limits on the total amount of antioxidants relative to the oil or fat content of the food, and criteria for its solidification point. Under 21 CFR 178.2550, the compound is also listed as an indirect food additive permitted in food-contact materials, again subject to prescribed conditions that define allowable concentrations and material performance considerations. These regulatory citations establish conditions under which the antioxidant may be safely used in foods and in materials that contact food as assessed by the FDA. Internationally, regulatory data such as the evaluations by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) provide context on safety assessments undertaken by global bodies. According to JECFA records, this compound was evaluated in the late twentieth century, and no acceptable daily intake (ADI) was allocated, with specifications subsequently withdrawn and no toxicological monograph prepared. Not allocating an ADI in this context reflects the limited scope of evaluation by that body rather than an explicit safety finding; therefore, regional and national regulations continue to define authorized uses based on local risk assessments. In jurisdictions outside the United States and FAO/WHO assessments, regulatory status may differ, and formulators must consult relevant national food additive regulations to determine permissible uses and limits. For example, in the European Union, comprehensive food additive lists and E-number designations apply to compounds authorized for direct addition to food, and where an EFSA opinion is not available or an E-number is not assigned, usage may not be permitted. Thus, the global regulatory landscape reflects both scientific evaluation and policy decisions regarding food additive use.
Taste And Functional Properties
As an antioxidant, 4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL is not typically used for its sensory attributes, and it does not impart a noticeable taste to food at the concentrations employed. In functional terms, antioxidants are selected based on their efficacy in slowing lipid oxidation, solubility characteristics, and compatibility with the food matrix. This compound is characterized by low water solubility and greater affinity for lipid phases, which aligns with its role in protecting fats and oils from oxidative degradation. Its performance depends on formulation factors such as concentration, the nature of the food matrix, and the presence of other antioxidants or synergists. Functionally, this antioxidant demonstrates stability under typical food processing conditions, which may involve moderate heat and exposure to atmospheric oxygen. Because oxidative reactions are accelerated by heat and exposure to light, incorporating a stable antioxidant helps foods withstand processing and storage conditions without rapid quality loss. Sensory neutrality is a desirable property for antioxidants because it allows formulators to achieve oxidative stability without altering the flavor profile. This neutrality enables foods to retain their expected taste while benefiting from increased shelf life and maintained quality. In applications where materials are used in food-contact articles, the functional properties similarly emphasize stabilization against oxidative deterioration rather than sensory effects. For example, in polymer stabilization, antioxidants like this help preserve the mechanical and barrier properties of plastics exposed to processing stresses. Because oxidative degradation can compromise these properties, the addition of antioxidants supports material performance without affecting the sensory attributes of the food with which the material contacts.
Acceptable Daily Intake Explained
An acceptable daily intake (ADI) is a concept used in toxicology and food safety risk assessment to describe the estimated amount of a substance that can be ingested daily over a lifetime without appreciable health risk. ADIs are typically expressed in milligrams of the substance per kilogram of body weight per day (mg/kg bw/day). Establishing an ADI requires extensive toxicological data, including long-term studies, to identify a no-observed-adverse-effect level (NOAEL), followed by application of safety factors to account for uncertainties in extrapolating animal data to humans and sensitive populations. For 4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) did not allocate an ADI in its evaluations, and corresponding specifications have been withdrawn in that context. The absence of an ADI means that a global reference value for daily intake was not established by that committee. In regulatory practice, the lack of an ADI does not inherently signify risk but indicates that the data reviewed did not lead to setting a numerical intake value. Instead, regulatory authorities such as the US Food and Drug Administration define conditions of use that effectively limit exposure based on application-specific constraints, such as maximum permitted levels in foods or in food-contact materials. When ADIs are established for other additives, they serve as benchmarks for risk managers to assess whether estimated dietary exposures fall within safe bounds. For consumers, the ADI provides a sense of the level at which long-term daily intake is not expected to pose appreciable risk, based on current scientific knowledge. It is important to note that ADIs are set with built-in safety margins, often orders of magnitude below levels that caused no adverse effects in animal studies. In the absence of an ADI for this compound, regulatory use limits and product-specific evaluations become key tools to ensure safety.
Comparison With Similar Additives
4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL belongs to a broader class of synthetic phenolic antioxidants used in food and industrial applications. A common comparator is butylated hydroxytoluene (BHT), another hindered phenolic antioxidant with widespread food additive authorization in many jurisdictions. BHT functions similarly in stabilizing lipid-containing systems by donating hydrogen to lipid radicals, thereby slowing oxidative chain reactions. Unlike 4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL, BHT has assigned regulatory designations (such as E321 in the European Union) and established conditions for use in foods under specific maximum levels set by regional food safety authorities. Butylated hydroxyanisole (BHA) represents another related antioxidant, often used in combination with BHT for synergistic effects in preserving fats and oils. BHA comprises a mixture of 2- and 3-tert-butyl isomers of hydroxytoluene and is also widely regulated with defined use levels. Both BHT and BHA have been evaluated extensively by multiple food safety authorities, which have established intake limits and application-specific permissions. In contrast, the lack of an ADI allocation for 4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL by JECFA and the specific conditions laid out by the US FDA reflect differences in the historical data base and regulatory considerations. Other antioxidants used in food applications include tertiary butylhydroquinone (TBHQ) and natural antioxidants such as tocopherols (vitamin E derivatives). TBHQ is recognized for high antioxidant efficacy at relatively low concentrations, while tocopherols offer generally recognized as safe (GRAS) status with usage spanning direct food addition. When selecting antioxidants for food formulation, technologists weigh functional efficacy, regulatory status, sensory neutrality, and established safety profiles. In this context, 4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL occupies a specific niche with defined conditions of authorized use rather than broad-spectrum approval across all food categories.
Common Food Applications Narrative
In the realm of food technology and formulation, antioxidants are employed to protect susceptible food components from oxidative stress. While not found in all categories of food, antioxidants such as 4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL are selected for use in applications where lipid oxidation poses a quality challenge. Common categories where lipid oxidation can be a concern include products rich in fats and oils, processed foods containing emulsified lipid phases, and certain extended-shelf-life items. By mitigating oxidation, antioxidants contribute to maintaining sensory quality and extending usable life for these foods. Examples of such applications encompass edible oils and fat spreads, where antioxidants help safeguard against rancidity that can develop during storage. In processed snacks and baked goods that incorporate lipid components, inclusion of antioxidants supports the retention of fresh flavor and structural attributes over time. Similarly, in ready-to-eat meals or convenience foods containing complex matrices of fats and oils, antioxidants are part of formulation strategies designed to enhance product stability and quality consistency. Beyond direct incorporation into food products, antioxidants like 4-HYDROXYMETHYL-2,6-DI-TERTBUTYLPHENOL may also appear in formulations for food-contact materials. In these applications, the compound assists in preserving material integrity during manufacturing and use, indirectly contributing to the protection of food quality. When these materials are used for packaging or processing aids, the regulated use of antioxidants under specified conditions ensures that their presence does not compromise food safety. In each of these contexts, food technologists balance functional efficacy with compliance to regulatory criteria to deliver safe, stable products to consumers.
Safety & Regulations
FDA
- Notes: Authorized as a direct and indirect food additive with specified use conditions under listed CFR sections.
- Approved: True
- Regulation: 21 CFR 172.150 and 21 CFR 178.2550
EFSA
- Notes: No EFSA opinion or E-number assigned based on available evidence.
JECFA
- Notes: JECFA did not allocate an ADI and specifications were withdrawn as per d evaluation.
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