2,2,4-Trimethylhexane (16747-26-5) Physical and Chemical Properties
2,2,4-Trimethylhexane
Branched nonpolar alkane used as a solvent and reference hydrocarbon in formulation, analytical, and R&D/QA workflows.
| CAS Number | 16747-26-5 |
| Family | Aliphatic hydrocarbons |
| Typical Form | Colorless liquid |
| Common Grades | EP |
2,2,4-Trimethylhexane is a saturated aliphatic hydrocarbon of the branched nonane isomer class; its molecular formula is \(\ce{C9H20}\). Structurally it consists of a six‑carbon backbone bearing methyl substituents at C‑2, C‑2 and C‑4 (IUPAC name: 2,2,4‑trimethylhexane). The absence of heteroatoms and pi-bonds yields a chemically nonpolar, non‑hydrogen‑bonding molecule with a topological polar surface area of 0 and zero formal charge, consistent with a low dielectric constant and high lipophilicity (computed XLogP3‑AA: 4.4).
As a branched alkane, the substance shows the typical physical and chemical behavior of low‑polarity hydrocarbons: liquid at ambient temperature, high solubility for nonpolar solutes, chemical inertness toward hydrolysis and mild acids/bases, and susceptibility to free‑radical processes such as combustion and autoxidation. It is thermally stable under routine handling but undergoes exothermic oxidation on combustion, and can be chlorinated or brominated under radical conditions. Industrial relevance derives from its role within the aliphatics solvent class and as a component or octane‑forming isomer in hydrocarbon blends.
Common commercial grades reported for this substance include: EP.
Physical Properties
Density and Phase
At ambient conditions 2,2,4‑trimethylhexane is a clear, colorless liquid (experimental physical description: "Clear colorless liquid"). No experimentally established value for density is available in the current data context.
Melting Point
No experimentally established value for this property is available in the current data context.
Boiling Point
No experimentally established value for this property is available in the current data context.
Vapor Pressure
Experimental vapor pressure is 15.9 \(\mathrm{mmHg}\). This vapor pressure is consistent with moderate volatility among C9 alkanes; vapor concentration control and adequate ventilation are necessary in enclosed spaces to limit inhalation exposure and flammable atmosphere formation.
Viscosity
No experimentally established value for this property is available in the current data context.
Chemical Properties
Flammability and Combustion
2,2,4‑Trimethylhexane is classified as a highly flammable liquid and vapor (GHS hazard statement H225; Flam. Liq. 2). As a nonpolar hydrocarbon it has a low flash point and supports rapid flame propagation; combustion yields carbon dioxide and water when complete, and carbon monoxide, soot and other incomplete‑combustion products under oxygen‑limited conditions. Precautions appropriate for volatile hydrocarbons—elimination of ignition sources, grounding and bonding during transfer, and use of explosion‑rated equipment—are required.
Reactivity and Typical Transformations
Chemically, this branched alkane is largely inert to nucleophilic substitution and hydrolysis. Typical laboratory and industrial transformations include: - Radical halogenation (chlorination/bromination) at elevated temperature or with radical initiators. - Catalytic cracking and isomerization under strong acid or high‑temperature catalytic conditions (relevant to refinery processes). - Autoxidation in the presence of oxygen and light can form hydroperoxides and oxygenated degradation products over time. - Complete oxidation (combustion) is an energetically favored pathway under oxidative conditions.
No specialized acid–base behavior, complexation, or hydrolytic cleavage is expected due to the saturated hydrocarbon framework.
Identifiers and Synonyms
Registry Numbers and Codes
- CAS RN: 16747-26-5
- EC number: 240-807-7
- UNII: 68L13E286X
- ChEBI: CHEBI:187668
- DSSTox Substance ID: DTXSID30868211
- LipidMaps ID: LMFA11000333
- Metabolomics Workbench ID: 5031
- Nikkaji number: J44.168F
- Wikidata: Q952800
- InChI:
InChI=1S/C9H20/c1-6-8(2)7-9(3,4)5/h8H,6-7H2,1-5H3 - InChIKey:
AFTPEBDOGXRMNQ-UHFFFAOYSA-N - SMILES:
CCC(C)CC(C)(C)C
Molecular weight: 128.25 (reported computed molecular weight) = 128.25 \(\mathrm{g}\,\mathrm{mol}^{-1}\). Exact/monoisotopic mass: 128.156500638.
Computed properties: XLogP3‑AA = 4.4; topological polar surface area = 0; hydrogen bond donors = 0; hydrogen bond acceptors = 0; rotatable bond count = 3.
Synonyms and Structural Names
Reported synonyms and name variants include (selected from depositor‑supplied names): 2,2,4‑TRIMETHYLHEXANE; 2,2,4‑trimethylhexane; Hexane, 2,2,4‑trimethyl‑; 2,2,4‑trimethyl‑hexane; (+/‑)‑2,2,4‑TRIMETHYLHEXANE. Other registry or database identifiers that function as synonyms are also available for cross‑reference.
Industrial and Commercial Applications
Use as Solvent or Fuel Component
As a saturated aliphatic hydrocarbon in the C9 range, 2,2,4‑trimethylhexane is classified among aliphatics and saturated solvents (<C12). It functions as a nonpolar solvent for hydrophobic materials (oils, waxes, nonpolar polymers) and can be present as an isomeric component in hydrocarbon fuel blends due to its branched structure, which affects volatility and combustion characteristics relative to linear isomers.
Representative Use Scenarios
Representative scenarios include use as a nonpolar solvent in organic synthesis or industrial formulations where low polarity is required, and inclusion in analytical standards and GC‑MS libraries for compound identification (numerous GC‑MS entries and library indices are associated with the substance). In practice selection is guided by solvent power for nonpolar solutes, volatility requirements, and flammability considerations.
Safety and Handling Overview
Flammability Hazards
This substance is highly flammable as a liquid and vapor (GHS: H225). Vapors can form explosive mixtures with air; ignition sources including static discharge must be controlled. Exposure by inhalation of high concentrations may cause central nervous system effects consistent with solvent exposure (reported adverse effect: acute solvent syndrome/neurotoxic effects). Eye and skin contact can cause irritation.
Storage and Handling Considerations
Store in a cool, well‑ventilated area away from heat and ignition sources in tightly closed containers designed for flammable liquids. Use grounding and bonding during dispensing to prevent static accumulation. Use appropriate personal protective equipment (gloves, eye protection) and engineering controls (local exhaust ventilation) to limit inhalation and dermal contact. For detailed hazard, transport and regulatory information, users should refer to the product‑specific Safety Data Sheet (SDS) and local legislation.
