CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE

CAS: 18433-93-7 FLAVORING AGENT OR ADJUVANT

CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE is a synthetic flavoring agent with fruity, ethereal notes, commonly used to impart aroma and taste complexity in food products. It is evaluated for use as a flavoring ingredient and has an associated FEMA GRAS determination referenced in authoritative flavoring ingredient libraries.

What It Is

CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE is a synthetic small molecule belonging to the class of organic compounds known as 1,3-dioxolanes, characterized by a five-membered ring containing two oxygen atoms and substituted with isobutyl and methyl groups. These structural features confer unique physicochemical properties, including a distinct sensory profile described as fruity, floral, and ethereal, which make it desirable in flavor formulation. The compound carries the CAS Registry Number 18433-93-7, a unique identifier used to track substances across scientific and regulatory databases. Although not assigned a traditional INS (International Numbering System) food additive number, this compound is referenced in flavor ingredient catalogs, especially by the Flavor and Extract Manufacturers Association (FEMA), where it is listed with FEMA GRAS Reference Number 4286, indicating that it has been evaluated for general recognition of safety as a flavoring substance when used in accordance with good manufacturing practice regarding levels of usage and conditions of intended use. In regulatory inventories such as the U.S. FDA Substances Added to Food database (formerly EAFUS), it appears as a listed flavoring agent or adjuvant under its primary chemical name with synonyms corresponding to variants of the 1,3-dioxolane structure. Despite its use in food formulation contexts, CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE is a specific technical ingredient rather than a broad category additive; its designation as a flavoring agent or adjuvant reflects its role in enhancing sensory properties rather than contributing to nutrition or preservation. The presence of both cis and trans stereoisomers underscores that the ingredient is often a mixture of molecular configurations, which may subtly influence its olfactory and gustatory characteristics in complex food matrices. These isomers are not separated in typical industrial preparations, and their combined sensory impact is integral to the ingredient's functional profile.

How It Is Made

The synthesis of CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE is typically achieved through an acetalization reaction between isovaleraldehyde (3-methylbutyraldehyde) and a glycol such as propylene glycol under acid-catalyzed conditions. In acetalization, an aldehyde reacts with a diol or glycol to form a cyclic acetal, in this case a 1,3-dioxolane ring. Industrial chemistry for flavoring ingredients often employs this type of reaction because it can be controlled to yield high purity products with the desired structural integrity, and the resulting cyclic acetals are generally more stable than simple open-chain acetals. In a typical process, isovaleraldehyde and propylene glycol are combined in the presence of an acid catalyst, such as sulfuric acid or a solid-supported acidic resin, to facilitate the nucleophilic attack of the glycol on the carbonyl carbon of the aldehyde. This step is followed by dehydration and ring closure to form the 1,3-dioxolane structure. Conditions are optimized to minimize side reactions and to achieve a balance of cis and trans stereochemical configurations, which are acceptable in the final flavoring ingredient. The resulting mixture is then purified, often using distillation under controlled vacuum, to achieve grade specifications suitable for use in flavor applications. Quality control for such flavoring agents involves assessing purity, sensory properties, and impurity profiles, because even small amounts of byproducts can significantly alter aroma or taste. Manufacturers also ensure that residual catalysts and unreacted starting materials are below established thresholds to meet regulatory and safety expectations. In general, production adheres to good manufacturing practices (GMP) for food grade chemicals, and facilities producing this compound for use in foods are expected to maintain documentation and controls appropriate for processing ingredients intended for human consumption contexts.

Why It Is Used In Food

CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE is utilized in food formulation primarily to enhance flavor profiles. Its sensory characteristics are described as fruity and ethereal, which can complement or reinforce natural fruit notes in beverages, confections, dairy-based products, and other complex food systems. Flavor chemists and product developers incorporate such compounds to achieve desired aroma and taste outcomes without relying exclusively on natural extracts, which can vary in composition or availability. The use of this compound as a flavoring agent reflects broader practices in the flavor industry, where specific molecules with defined organoleptic properties are added at low concentrations to improve or harmonize sensory perception. It is particularly useful for providing subtle fruity, tropical, or floral nuances that can elevate the overall profile of a product. As a flavor adjuvant, it may also interact with other flavor components to modify how taste perceptions are integrated by consumers, making it a valuable tool for achieving targeted sensory goals. Importantly, the decision to use synthetic flavoring agents like CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE is guided by formulation objectives, regulatory compliance, and considerations of consistency and cost. Synthetic molecules can offer more predictable performance and supply compared to some natural extracts, and they allow formulators to fine-tune flavor impact with precision. Their inclusion in food and beverage products is typically at trace levels, and they are intended to complement other ingredients rather than contribute nutritional value or functional roles such as preservation or texture modification.

Adi Example Calculation

An illustrative calculation of hypothetical exposure to a flavoring agent such as CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE can help contextualize how low levels used in food contribute to overall intake. Suppose a beverage product contains a flavor formulation where this compound is present at a concentration of 1 mg per liter, which is a generous assumption for a flavor molecule used at trace levels. If a person consumes 2 liters of such a beverage in a day, their total intake of the compound would be 2 mg for that day. For illustrative purposes, if a numeric ADI were hypothetically established at 1 mg per kg body weight, a person weighing 70 kg would have a theoretical allowable intake of 70 mg per day. In this hypothetical scenario, the estimated intake of 2 mg from beverage consumption would be well below that threshold, illustrating how low usage levels result in exposures far below conservative safety limits. It is important to emphasize that this example uses a made-up ADI value for demonstration and should not be interpreted as specific guidance for this compound, because no formal numeric ADI is publicly documented from regulators. This type of illustration underscores how flavoring agents, by virtue of their typical usage concentrations and patterns of consumption, contribute minimally to overall chemical exposure compared to other dietary components. It also highlights why expert panels often focus on aggregate exposure and toxicological margins rather than assigning specific numeric ADIs for every flavor compound assessed.

Safety And Health Research

Safety assessment for flavoring agents such as CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE typically involves reviewing toxicological data across multiple endpoints, including subchronic toxicity, genotoxicity, and metabolism, to determine whether the compound exhibits any intrinsic hazards at anticipated exposure levels. While detailed regulatory monographs specific to this compound may not be openly published with numerical ADI values, expert panels like those convened by FEMA and referenced through JECFA flavor numbers review available data and scientific literature as part of their evaluations. These assessments focus on evidence from animal studies, chemical structure-activity relationships, and exposure estimates derived from usage levels in food categories to establish whether any potential safety concerns exist at typical use concentrations. It is important to distinguish between hazard identification and risk assessment. The former involves characterizing the intrinsic potential for adverse effects, while the latter weighs that potential against the levels of human exposure expected from consumption of products containing the compound. For many flavoring agents, including this dioxolane derivative, usage levels are managed to remain well below thresholds where toxicity has been observed in experimental systems, and the compound’s structural class does not suggest high concern for genotoxicity or reproductive toxicity based on available data reviews conducted by flavor expert bodies. However, exhaustive primary toxicological data for every flavor compound may not be publicly accessible, and often proprietary safety studies are submitted to evaluative panels. Regulatory evaluations do not equate to medical guidance, and safety research continues as new data emerge. The consensus among expert flavor panels is that CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE can be used safely at low levels typical for flavoring purposes, but individual product applications should always adhere to relevant food safety standards and labeling requirements in specific markets.

Regulatory Status Worldwide

The regulatory status of CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE varies across jurisdictions but generally aligns with classifications for flavoring agents rather than structured food additive listings. In the United States, the compound appears in the FDA Substances Added to Food database (formerly EAFUS) as a listed ingredient used for its technical function as a flavoring agent or adjuvant, reflecting recognition for its intended use in food under conditions of good manufacturing practice. The listing provides key identifiers including its CAS number and synonyms, though it does not represent an explicit FDA regulation with a defined section of Title 21 of the Code of Federal Regulations permitting its use at specified levels. Rather, the database inclusion supports regulatory transparency about substances that may be added to food within the scope of existing flavoring usage frameworks. In addition, the Flavor and Extract Manufacturers Association (FEMA) maintains a Flavor Library where CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE is assigned FEMA GRAS Reference Number 4286, indicating that expert panels have evaluated available data and concluded that it is generally recognized as safe as a flavoring substance when used in accordance with good manufacturing practice. This GRAS evaluation is widely referenced by industry professionals, though it is distinct from an FDA regulation. Internationally, references such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA) assign a flavor number (1732) for tracking but do not necessarily provide an Acceptable Daily Intake (ADI) or formal numerical limit for general food additive use, which reflects that many flavor compounds are managed through separate expert review processes rather than traditional additive authorization schemes with strict numerical limits. Overall, the regulatory landscape for this compound is typical of many flavoring agents in that inclusion in authoritative flavor ingredient inventories and recognition by expert panels provide reassurance about its suitability for intended uses, but specific regulatory text with quantified limits may not be present in every jurisdiction. Manufacturers and formulators are expected to comply with applicable food safety frameworks and usage guidelines relevant to their markets, and context-specific documentation may be required for labeling and safety assessments.

Taste And Functional Properties

From a sensory perspective, CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE is characterized by a fruity and ethereal aroma that may be described as having hints of tropical fruit, apple, or banana nuances at appropriate concentration levels. The compound's odor profile is a key determinant of its utility in flavor formulation, as the compound is selected specifically for the way it alters aroma perception when incorporated into a food matrix. The functional properties of this ingredient extend beyond simple aroma impact. It is typically soluble in a range of organic solvents and carriers used in flavor production, and its relative stability allows it to remain effective under typical processing conditions encountered in beverage production, confection manufacturing, and other food processing scenarios. However, like many small organic molecules, its stability can be affected by extreme pH conditions or prolonged exposure to heat, so formulators consider such factors when specifying inclusion levels and processing steps. In practical terms, flavor chemists evaluate this ingredient not only for its intrinsic sensory characteristics but also for how it interacts with other components in a formulation. Some molecules can mask off-notes, enhance sweetness perception indirectly, or synergize with other esters and aldehydes to produce a balanced profile. CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE’s role is primarily as a contributor to overall aroma complexity rather than a dominant flavor on its own, and it is often used in combination with other flavoring agents to achieve desired sensory outcomes.

Acceptable Daily Intake Explained

The concept of an Acceptable Daily Intake (ADI) is central to food additive safety frameworks. ADI represents an estimate of the amount of a substance, expressed per unit body weight, that can be ingested daily over a lifetime without appreciable health risk. However, for many flavoring agents such as CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE, formal numerical ADI values are not always established in the same way they are for broad-use food additives like preservatives or sweeteners. Instead, expert panels reviewing flavor compounds consider exposure estimates and toxicological profiles and determine that the compound can be used safely under conditions of good manufacturing practice without deriving a single numerical ADI. When numerical ADIs are established, they incorporate safety factors that account for uncertainties in the data, such as differences between animal test systems and human populations, to ensure a broad margin of safety. For flavor ingredients, exposure tends to be relatively low because these compounds are used at trace levels to achieve sensory effects, which further reduces risk. An ADI, if present, would provide a regulatory context for risk managers and product developers to assess whether typical use levels remain well below conservative thresholds of concern. Because CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE does not have a widely published numeric ADI assigned by regulators, its acceptability in foods is tied to expert consensus on safe usage rather than adherence to a specific mg per kg body weight figure. This approach is common for many flavor compounds evaluated under expert review programs rather than traditional additive authorization systems, and it emphasizes the role of exposure assessment and professional judgment in ensuring that consumer intake remains within safe boundaries.

Comparison With Similar Additives

CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE can be compared with other flavoring agents that share similar functional roles in product formulation. For example, many aldehyde-derived acetals such as benzaldehyde propylene glycol acetal, butyraldehyde propylene glycol acetal, and anisaldehyde propylene glycol acetal serve as flavor ingredients with distinct sensory profiles. Benzaldehyde propylene glycol acetal may contribute almond-like notes, while anisaldehyde propylene glycol acetal can add sweet, floral accents. In contrast, CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE tends toward fruity and ethereal qualities. Another category of flavor adjuncts includes esters such as ethyl butyrate or ethyl acetate, which are commonly used for their strong fruit flavor impressions. These esters differ from dioxolane derivatives in both chemical structure and volatility behavior, often imparting more intense fruit characteristics at lower concentrations. Compared to such esters, CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE typically plays a subtler role, providing background depth rather than a dominant taste note. Understanding these comparisons helps formulators select combinations of flavoring agents that complement one another and achieve balanced sensory outcomes. Each compound’s contribution depends on its odor profile, volatility, and interactions with other ingredients, and effective flavor design often involves blending multiple additives to create complexity and consumer appeal.

Common Food Applications Narrative

In food and beverage applications, CIS- AND TRANS-2-ISOBUTYL-4-METHYL-1,3-DIOXOLANE is incorporated for its ability to contribute nuanced aroma characteristics that enhance consumer perception of fruitiness, tropical notes, or ethereal sweetness. For example, in nonalcoholic beverages the compound may be included in blends targeting apple, pineapple, or other fruit-forward profiles to bolster the authenticity and complexity of the aroma. In dairy-based desserts or frozen confections, its subtle fruity facets can provide background support to richer flavor components, making the overall sensory experience more layered and appealing. Confectionery applications also benefit from the inclusion of such flavoring agents. In hard or soft candies, where sugar and other modulators dominate the taste profile, small amounts of this dioxolane derivative can add depth to fruit-flavored lines, particularly when combined with complementary esters and aldehydes. Similarly, in baked goods and breakfast cereals, its presence at trace levels can reinforce fruit essence notes in products that include dried fruits or fruit inclusions, harmonizing with natural and artificial flavors to achieve a cohesive sensory identity. The use of this compound is consistent with industry practices where specific aroma molecules are selected to achieve targeted effects in complex matrices. Its contribution is generally subtle and designed to support overall flavor perception rather than to serve as a primary taste driver. Because it is used at low concentrations under flavor industry guidelines, it does not materially alter the nutritional composition of the finished food product but instead influences how consumers perceive aroma and taste in their eating and drinking experiences.

Safety & Regulations

FDA

  • Notes: Included in FDA Substances Added to Food database but no specific CFR regulation text permitting use at defined levels could be found

EFSA

  • Notes: No specific EFSA additive authorization or numeric ADI was found in available authoritative reports

JECFA

  • Notes: JECFA flavor number is provided but a numeric ADI or evaluation year was not explicitly documented on the d entry
  • Ins Number: 1732

Sources

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