OTBCHA (Verdox®)

OTBCHA / Verdox® (88-41-5) Synthetic Ingredient Overview

• 🏭 Manufacturer — IFF (Verdox®), Firmenich (Agrumex HC), Symrise, H&R

• 🔎 Chemical Name — 2-tert-Butylcyclohexyl acetate (ortho isomer)

• 🧪 Synonyms — Verdox®, Agrumex HC, Green Acetate, Ortholate, Ylanate Ortho, OTBCHA, o-tert-Butylcyclohexyl acetate

• 🧬 Chemical Formula — C₁₂H₂₂O₂

• 📂 CAS Number — 88-41-5

• 📘 FEMA Number — Not listed (not approved for food use)

• ⚖️ Molecular Weight — 198.30 g/mol

• 🌡️ Melting Point — 34.5-35.4°C (pure cis isomer)

• 🔬 Refractive Index — n²⁰D 1.4500-1.4560

• 📊 Density — d²⁵₂₅ 0.938-0.944

• 📝 Odor Type — Fruity, woody, green

• 📈 Odor Strength — Medium to strong

• 👃🏼 Odor Profile — Fresh apple, fruity-green, woody, violet-like; dry powdery ionone with cashmeran and amber nuances

• ⚗️ Uses — Fruity tea effects, floral-violet enhancement, modern woody support, apple accords, green-tea notes

• 🧴 Appearance — Colorless to pale yellow liquid; may solidify in cold temperatures

What is OTBCHA (Verdox®)?

OTBCHA is a synthetic aliphatic ester featuring a tert-butyl-substituted cyclohexyl ring system. The molecule exists as cis and trans stereoisomers, with commercial products typically containing 60-95% of the cis isomer. The pure cis-2-tert-butylcyclohexyl acetate is a crystalline solid with a more pronounced fruity, agrumen-like (citrus-green) character, while increasing percentages of the trans isomer shift the profile toward woody-camphorous notes (Surburg & Panten, 2006).

Marketed under various trade names including Verdox® (IFF), Agrumex HC (Firmenich/Symrise), and Ortholate (Quest), OTBCHA has become a valuable building block in modern perfumery. Despite being catalogued as "fruity," its character is not sugary or overtly edible—instead, it delivers a fresh, clean, structurally complex aroma that intersects fruity top notes with woody-powdery mid/base effects.

The molecule's tert-butyl group provides steric bulk that influences both its volatility and odor profile, creating an unusual combination of freshness and tenacity. This makes OTBCHA particularly useful for perfumers seeking volume, smooth transitions, or lift in their formulas without dominating the composition.

Historical Background

OTBCHA (2-tert-butylcyclohexyl acetate) was developed as part of the broader exploration of tert-butylcyclohexyl esters in mid-20th century fragrance chemistry. The molecule is synthesized through esterification of 2-tert-butylcyclohexanol, which itself is obtained from 2-tert-butylphenol through catalytic hydrogenation (Surburg & Panten, 2006).

Verdox®, the most well-known commercial variant, was created and launched by IFF (International Flavors & Fragrances) in 1991 as a proprietary material designed to deliver apple notes with an intense woody facet to perfume compositions (Fragrantica, 2021). The development of Verdox® represented IFF's effort to create a versatile synthetic that could serve multiple roles—functioning as both a fruity top note and a woody-ambery modifier.

Throughout the 1990s and 2000s, OTBCHA gained popularity as a reliable modifier for green-fruity accords, particularly in functional perfumery applications like shampoos, fabric softeners, and household products where its excellent stability in alkaline conditions proved valuable. The molecule's ability to blend seamlessly with florals, woods, and musks while adding freshness without sweetness made it a staple in modern perfumer's palettes.

While IFF discontinued production of Verdox® in recent years, the molecule continues to be produced by multiple manufacturers under different trade names, including Agrumex HC (Firmenich/Symrise) and generic OTBCHA from various suppliers. High-cis versions (>90% cis isomer) command premium prices due to the expensive separation process required to isolate stereoisomers.

Olfactory Profile

Scent Family

Primary: Fruity-Green

Secondary: Woody, Powdery-Floral

Main Descriptors

• Primary: Fresh apple, green fruit, clean

• Secondary: Woody-cedar, violet-ionone, powdery

• Tertiary: Slight camphoraceous undertone (trans isomer), tea-like, amber-cashmeran facets

OTBCHA delivers a multifaceted olfactory experience that evolves from fresh apple-green top notes into violet-like powdery florals, finishing with woody-ambery drydown. The scent is abstract and complex—not a photorealistic apple, but rather a sophisticated interpretation that suggests fruit, forest, and flowers simultaneously.

Intensity

Medium to strong. OTBCHA is potent but not overwhelming—it performs well even at low concentrations (0.5-2%) yet can be used in higher amounts (5-15%) without dominating a composition. Its diffusive character means a little goes a long way in creating olfactory impact.

Tenacity

Medium. As an acetate ester with moderate volatility, OTBCHA functions primarily in the top-to-heart notes, lasting approximately 4-8 hours on a blotter. Its tenacity is longer than simple aliphatic esters but shorter than woody molecules, making it an excellent bridge material.

Volatility

Top to mid note material with moderate volatility. The molecular weight (198.30 g/mol) places it between typical top notes and heart notes, allowing it to provide both initial freshness and sustained presence through the development phase of a fragrance.

Stereochemistry and Odor Variation

The cis/trans isomer ratio significantly impacts olfactory character:

• High-cis (>90%): More fruity-floral, less woody-camphorous, more intense jasminic-violet character

• Mixed (60-80% cis): Balanced fruity-woody profile typical of commercial grades

• Higher trans content: More woody-camphorous, less fruity brightness

Applications in Fine Fragrance

OTBCHA serves as a versatile modifier and structural element across multiple fragrance families:

• Modern Florals: Adds fresh lift to peony, violet, narcissus, and mimosa accords; contributes tea-like transparency

• Fruity-Floral Compositions: Creates sophisticated apple-pear effects; blends with berry notes and stone fruits

• Woody Ambers: Enhances cashmeran, Iso E Super-type woods, and cedar bases with fruity-fresh facets

• Green-Tea Fragrances: Essential for realistic tea leaf effects; pairs with hedione, linalool, and green aldehydes

• Functional Perfumery: Excellent in shampoos, conditioners, fabric softeners due to alkaline stability

Notable Pairings:

• With musks: Adds freshness to ambrettolide, galaxolide, and white musks

• With ionones: Reinforces violet-powdery effects in α-ionone and β-ionone blends

• With aldehydes: Creates complex fruity-soapy effects with C10, C11 aldehydes

• With woods: Softens cedar, sandalwood, and vetiver with fruity warmth

Typical usage: 1-10% in fine fragrance concentrates; up to 15% in functional applications.

Performance in Formula

Dosage and Blending Behavior

• Recommended Concentration: 1-10% in fine fragrance; up to 15% in functional perfumery

• Threshold: Detectable at approximately 0.5-1% where it begins contributing character

• Optimal Range: 3-7% for balanced fruity-woody effects without domination

OTBCHA is described as a "good blender" and "excellent connector" in perfumery, meaning it facilitates smooth transitions between different olfactory families. It's particularly effective at bridging fruity top notes to woody bases, or connecting green-herbal accords to floral hearts.

Formulation Characteristics

• Stability: Highly stable in both acidic and alkaline conditions; excellent for soap, shampoo, and detergent formulations

• Solubility: Fully miscible with alcohols and perfume oils; may solidify at temperatures below 20°C (especially high-cis grades)

• Reactivity: Inert under normal storage conditions; does not participate in Schiff base reactions or oxidation

• Compatibility: Blends seamlessly with aldehydes, esters, terpenes, ionones, musks, and woody materials

Impact on Fragrance Structure

OTBCHA adds volume and radiance without weight—it lifts compositions vertically (increasing diffusion) while maintaining transparency. Unlike heavy fixatives, it doesn't slow down top note evolution but rather creates a smooth pathway from opening to heart.

In functional applications, OTBCHA's resistance to oxidation and discoloration makes it ideal for products with long shelf lives or exposure to light, heat, and alkalinity.

Industrial & Technical Uses

OTBCHA is predominantly used in:

Fine Fragrance

• Floral-fruity feminine perfumes

• Woody-fresh masculine colognes

• Unisex green-tea and woody-amber compositions

Functional Perfumery

• Hair Care: Shampoos, conditioners, hair sprays (excellent alkaline stability)

• Fabric Care: Detergents, fabric softeners, laundry additives

• Personal Care: Body lotions, shower gels, deodorants

• Home Care: Room sprays, air fresheners, surface cleaners

Technical Advantages

• Stable across pH 3-11 (suitable for acid perms to alkaline detergents)

• No discoloration over time

• Compatible with surfactants and emulsifiers

• Low volatility loss during formulation

Not suitable for flavor use—OTBCHA is not GRAS-listed and should never be used in food or oral applications. It is exclusively a fragrance material.

Regulatory & Safety Overview

IFRA Status: Permitted for use in fragrances without specific restrictions under IFRA Standards 51st Amendment (2024). Follow standard category-based guidance for esters and cyclohexyl compounds (IFRA, 2024).

EU Cosmetics Regulation (EC) No 1223/2009: Approved for use in cosmetic products. Not listed among the 26 declarable fragrance allergens. No special labeling requirements.

FEMA Status: Not listed. Not approved for food use or flavor applications.

REACH Registration: Registered with ECHA (European Chemicals Agency). Not classified as hazardous under CLP regulation.

Toxicology:

• No known dermal sensitization at typical use concentrations

• Low acute toxicity

• Not persistent or bioaccumulative in the environment

• Generally well-tolerated in cosmetic and fragrance applications

GHS Classification: Some suppliers classify as "Warning" for minor irritant potential; follow standard perfumery handling practices.

Storage Recommendations: Store in cool, dry conditions away from heat sources. May solidify below 20°C (especially high-cis grades); warming to room temperature restores liquid state without quality loss.

✅ OTBCHA is considered safe for all fragrance applications within recommended usage levels and complies with global cosmetic and perfumery regulations.

References

• ECSA Chemicals. (2021). OTBCHA and PTBCHA in the fragrances world. Retrieved from https://ecsa-chemicals.ch/en/otbcha-and-ptbcha-in-the-fragrances-world/

• European Chemicals Agency (ECHA). (n.d.). Substance information: 2-tert-Butylcyclohexyl acetate, CAS 88-41-5. Retrieved from https://echa.europa.eu/

• Fragrantica. (2021). Verdox perfume ingredient. Retrieved from https://www.fragrantica.com/notes/Verdox-1053.html

• International Fragrance Association (IFRA). (2024). IFRA Standards – 51st Amendment. Retrieved from https://ifrafragrance.org/safe-use/standards-documentation

• Surburg, H., & Panten, J. (2006). Common fragrance and flavor materials: Preparation, properties and uses (5th ed., pp. 90-91). Wiley-VCH.