C11

C11
Name	C11
Othernames	Undecane (common name)
Cas	112-84-5
Formula	C11H24
Density	0.749 g/cm3 (liquid)
Mp	−26 °C
Bp	196–198 °C
Solubility	Insoluble in water
Appearance	Colorless liquid

C11

C11 is the molecular formula commonly used to denote the eleven‑carbon straight or branched alkane series exemplified by undecane, a colorless, flammable hydrocarbon liquid. It appears in petrochemical streams, fragrance formulations, fuel fractions, and organic synthesis, and is characterized by physical and chemical behavior typical of higher alkanes encountered in industrial chemistry. Analysts and engineers encounter C11 in contexts ranging from distillation units at Royal Dutch Shell refineries to formulation labs at Givaudan and Firmenich where volatility and odor profile are critical.

Overview

Undecane and its isomers fall within the homologous series that includes decane and dodecane, sharing trends in boiling point, density, and reactivity with other alkanes such as n‑hexane and n‑heptane. Producers include major petroleum companies like ExxonMobil and BP, while specialty suppliers such as Sigma-Aldrich provide laboratory‑grade material. In petrochemical nomenclature, the straight‑chain isomer is often designated n‑undecane; structural isomers are relevant to performance in applications linked to Procter & Gamble product formulations and solvent selection at firms like Dow Chemical Company.

Technical Specifications

Undecane (C11H24) has a molecular weight of 156.31 g·mol−1 and exhibits a boiling point near 196–198 °C, a melting point around −26 °C, and a density approximately 0.749 g·cm−3 at 20 °C. As a saturated hydrocarbon, it is chemically inert toward many reagents but undergoes typical alkane reactions: radical halogenation under photochemical conditions, cracking over solid acid catalysts like those used by LyondellBasell, and combustion with oxygen used in combustion studies referenced by laboratories at National Institute of Standards and Technology. Its vapor pressure and flash point are parameters regulated for transport by International Maritime Organization and classified under packing groups used by United Nations model regulations for dangerous goods. Analytical characterization employs gas chromatography columns from Agilent Technologies and detectors calibrated with standards from National Institute for Occupational Safety and Health.

Applications and Usage

C11 components are present in light petroleum fractions employed as solvents in specialty cleaning produced by companies such as 3M and in fuel blends used in aviation kerosene studies at Boeing research facilities. In the fragrance industry, specific undecane isomers contribute to top and middle notes in blends developed by houses like Versace and Chanel, while formulators at L’Oréal consider volatility and olfactory thresholds. Chemical manufacturers use C11 isomers as intermediates in the synthesis of plasticizers and lubricants marketed by Mobil 1 and Castrol, and as feedstocks in catalytic reforming units operated by Chevron. Research on combustion kinetics involving C11 isomers appears in studies from universities such as Massachusetts Institute of Technology and Stanford University examining hydrocarbon oxidation mechanisms relevant to internal combustion engines studied by General Motors.

History and Development

Alkane chemistry traces to early organic chemistry work by chemists like August Kekulé and industrial investigations in the 19th century by companies evolving into Shell Oil Company. Systematic isolation of higher alkanes including C11 emerged with advances in fractional distillation at refineries during the early 20th century, and subsequent structural elucidation benefited from spectroscopic methods developed at institutions such as University of Cambridge and California Institute of Technology. The mid‑20th century expansion of petrochemical industries at conglomerates like DuPont accelerated the commercial use of undecane fractions, while volatile organic compound regulation by agencies including the United States Environmental Protection Agency influenced handling practices and emissions controls.

Variants and Compatibility

C11 denotes not only n‑undecane but a family of positional and chain‑branched isomers (e.g., 2‑methyldecane, 3‑ethylnonane) whose physical and sensory properties vary; manufacturers like BASF and INEOS supply specific isomeric mixtures tailored to applications. Compatibility considerations include solvent miscibility with aromatics such as those from TotalEnergies, and material compatibility with elastomers specified by automakers like Ford Motor Company and Toyota Motor Corporation when used in fuel system testing. In analytical practice, reference spectra from Wiley libraries assist in distinguishing isomers on mass spectrometers manufactured by Thermo Fisher Scientific.

Safety and Standards

Undecane and its isomers are flammable liquids with health and safety profiles addressed in safety data sheets from suppliers including Brenntag and Univar Solutions. Occupational exposure limits and handling guidelines reference standards promulgated by Occupational Safety and Health Administration and exposure assessment protocols used by Centers for Disease Control and Prevention. Transportation is regulated under International Air Transport Association Dangerous Goods Regulations and ADR for road transport in Europe, with classification influenced by flash point and boiling range. Firefighting measures, spill response, and environmental impact assessments are informed by guidance from United Nations Environment Programme and incident response organizations such as National Response Center.

Category:Alkanes