Docosylbenzene
[CAS 68855-24-3]

Identification

• Classification: Organic raw materials >> Hydrocarbon compounds and their derivatives >> Aromatic hydrocarbon
• Name: Docosylbenzene
• Molecular Formula: C₂₈H₅₀
• Molecular Weight: 386.70
• CAS Registry Number: 68855-24-3
• EC Number: 272-472-8
• SMILES: CCCCCCCCCCCCCCCCCCCCCCc1ccccc1

Properties

• Density: 0.9±0.1 g/cm³ Calc.^*
• Boiling point: 448.1±8.0 °C 760 mmHg (Calc.)^*
• Flash point: 206.7±6.2 °C (Calc.)^*
• Index of refraction: 1.48 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS05 Warning
• Risk Statements: H302-H315-H319-H335
• Safety Statements: P280-P305+P351+P338

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315

chemBlink Chemical Story

The name "docosylbenzene" suggests a neat picture: one benzene ring carrying one C22 alkyl chain. CAS 68855-24-3 deserves more caution. Regulatory sources commonly identify this CAS as benzene, C14-30-alkyl derivatives - a long-chain alkylbenzene mixture rather than a single, uniquely defined docosylbenzene molecule. That difference is not a technical footnote; it changes how the material should be understood.

Long-chain alkylbenzenes sit at an interesting boundary between aromatic and paraffinic chemistry. The benzene ring is a rigid aromatic core, while the long alkyl chain behaves more like a waxy hydrocarbon. Increasing chain length raises hydrophobicity and changes viscosity, melting behavior, solubility, and interaction with oils. A distribution of C14-C30 chains therefore gives a material a broader physical-property profile than one pure homolog would have.

Why make such compounds at all? One major reason is that alkylbenzenes are versatile industrial intermediates. Sulfonation of an alkylbenzene converts the aromatic ring into an anionic surfactant precursor: the long alkyl group supplies the hydrophobic tail, while the newly introduced sulfonate group supplies the water-loving head. Shorter linear alkylbenzenes became foundational detergent feedstocks. Much longer alkylbenzenes occupy a more oil-soluble part of the spectrum and can also appear in lubricant and specialty-fluid chemistry, where their hydrocarbon-rich character is useful.

The route to long-chain alkylbenzenes also illustrates a classic refinery-to-specialty-chemical transformation. Olefins or other alkylating agents can attach long hydrocarbon chains to benzene under acid-catalyzed conditions. What begins as commodity aromatic and olefin feedstock becomes a molecule whose balance of aromaticity and paraffinic chain length can be tuned for downstream use. If the product is intended for sulfonation, the alkyl chain is not decorative: it determines hydrophobic strength, solubility of the eventual sulfonate, and formulation behavior.

For CAS 68855-24-3, the safest scientific description is therefore the broader regulatory one. A product sold under the convenient name docosylbenzene may be enriched in a C22 component, but the CAS identity itself covers a C14-C30 alkylbenzene distribution. Treating it as one pure C28H50 compound would erase exactly the feature that matters most in industrial practice - compositional breadth.

This material is memorable because it shows how industrial chemistry often works with families rather than perfect molecules. One aromatic ring plus a long hydrocarbon chain creates a bridge between petrochemical feedstocks, oil-soluble functional materials, and the chemistry that can later turn hydrophobic alkylbenzenes into surfactants.

References:
1. eChemPortal, CAS 68855-24-3, regulatory identity: Benzene, C14-30-alkyl derivatives.
2. Australian Industrial Chemicals Introduction Scheme (AICIS), assessment/inventory resources for long-chain alkylbenzenes.
3. Ullmann's Encyclopedia of Industrial Chemistry, Alkylbenzenes / surfactant feedstocks.
4. EPA and international chemical inventory records for CAS 68855-24-3.

Read more stories