Introduction
C11H14O2 is a chemical formula that describes a class of organic compounds containing eleven carbon atoms, fourteen hydrogen atoms, and two oxygen atoms. Because the formula does not specify connectivity, it corresponds to a number of structural isomers that span several functional group categories, including esters, acids, alcohols, and ketones. The compounds sharing this formula are of interest in organic synthesis, fragrance chemistry, agrochemical development, and pharmaceutical research. Understanding the diversity of structures that satisfy the molecular formula allows chemists to classify related compounds, predict physicochemical properties, and design synthetic routes for target molecules.
Structural Isomers
Aromatic Esters
Several aromatic esters have the composition C11H14O2. A common motif is the phenyl acetate derivative, where a phenyl ring is bonded to an acetyl group through an ester linkage. Variations include ortho-, meta-, and para-substituted phenylacetates, each differing in the position of the methyl or other substituents on the aromatic ring. These esters often exhibit characteristic esterification reaction patterns, such as the formation of acetic acid upon hydrolysis.
Aromatic Acids
The formula also accommodates benzoic acid derivatives. For example, 2-phenylpropanoic acid contains a phenyl group attached to a propanoic acid chain. The presence of the carboxyl group gives these molecules acidity and the ability to form salts and esters. Isomeric acids with different alkyl chain lengths or branching also fall within the same molecular formula.
Aldehydes and Ketones
Compounds such as 4-phenyl-2-butanone (also known as 4-phenyl-2-butanone) are examples of C11H14O2 ketones. Here, a phenyl ring is attached to a carbonyl group that is further substituted by a butyl chain. Aldehyde analogues exist as well, though they are less common in industrial contexts due to reactivity.
Alcohols
Primary, secondary, and tertiary alcohols with the same composition can be constructed. An example is 4-phenyl-2-butanol, where the alcohol functional group replaces the carbonyl in the ketone isomer. Alcoholic variants are frequently used as intermediates in synthetic routes to esters or other functionalized derivatives.
Other Functional Group Variants
Less common isomers include compounds containing both a hydroxyl and a carboxyl group (i.e., diols or hydroxy acids). For instance, 3-phenyl-3-hydroxybutanoic acid features both a carboxylic acid and a secondary alcohol. Such molecules find niche applications in polymer chemistry and as building blocks for more complex natural product synthesis.
Physical and Chemical Properties
Molecular Weight and Formula Mass
The exact mass of a molecule with the formula C11H14O2 is calculated by summing the atomic masses: 11×12.0107 + 14×1.0079 + 2×15.9994 = 154.213 g/mol. This relatively low molecular weight contributes to moderate volatility and facilitates chromatographic separation.
Boiling and Melting Points
Physical data vary among isomers. Aromatic esters typically exhibit boiling points between 140 °C and 180 °C, with melting points ranging from −40 °C to −10 °C. Alcoholic isomers often show higher boiling points (170–220 °C) due to hydrogen bonding, whereas ketone analogues have intermediate values (150–190 °C). The presence of polar functional groups such as carboxylic acids can raise the boiling point further, often beyond 220 °C.
Solubility
Solubility in water is generally limited for aromatic esters and ketones, with log P values around 2–3, indicating moderate lipophilicity. Hydroxyl-bearing compounds (alcohols, acids) show increased water solubility; for example, 3-phenyl-3-hydroxybutanoic acid has a log P near 0.5 and dissolves readily in aqueous media at neutral pH. Solubility in organic solvents such as ethanol, ethyl acetate, and dichloromethane is high across the series.
Spectroscopic Signatures
Infrared spectroscopy of C11H14O2 isomers typically displays strong absorptions near 1715 cm⁻¹ for carbonyl groups (esters, ketones, acids), while alcohols show broad O–H stretches around 3300 cm⁻¹. Raman spectra reveal characteristic ring breathing modes near 1600 cm⁻¹ for aromatic systems. Nuclear magnetic resonance spectroscopy provides detailed information: ^1H NMR signals for aromatic protons appear between 7.0 and 8.0 ppm, whereas aliphatic protons resonate between 0.8 and 3.5 ppm. Carbon-13 NMR signals for carbonyl carbons lie at 170–200 ppm, depending on the functional group.
Synthesis and Production
Acylation Reactions
A prevalent synthetic route for aromatic esters involves Friedel–Crafts acylation of benzene derivatives with acyl chlorides (e.g., acetyl chloride) in the presence of Lewis acids such as aluminum chloride. Subsequent esterification with alcohols or phenolic hydroxyl groups yields the final C11H14O2 product. The reaction is exothermic and requires careful temperature control to avoid over‑acylation.
Reductive Methods
Reduction of ketone or aldehyde precursors using hydride donors (e.g., sodium borohydride, lithium aluminium hydride) furnishes the corresponding alcohols. For example, reduction of 4-phenyl-2-butanone produces 4-phenyl-2-butanol. Conditions vary according to solvent choice (ethanol, THF) and stoichiometry, with side reactions such as over‑reduction of ester groups minimized by selective catalysts.
Oxidative Pathways
Oxidation of primary alcohols with oxidants like PCC (pyridinium chlorochromate) or Dess–Martin periodinane generates aldehydes, which can be further oxidized to acids. These transformations allow access to carboxylic acid isomers from simpler alcohol precursors. Catalytic oxidation using metal oxides (e.g., CuO, Pd/C) in aqueous media provides greener alternatives.
Coupling Reactions
Modern synthetic chemistry employs cross‑coupling reactions such as Suzuki–Miyaura or Heck reactions to build C–C bonds between aromatic and aliphatic fragments. For instance, a Suzuki coupling between a boronic acid phenyl derivative and an alkenyl bromide yields a substituted alkene, which can then undergo hydrogenation and further functionalization to reach the C11H14O2 framework.
Biomimetic and Enzymatic Strategies
Enzymatic esterification using lipases or whole‑cell biocatalysts offers a stereoselective route to chiral alcohol and ester isomers. Immobilized lipases can operate in non‑aqueous solvents, achieving high enantiomeric excess in the synthesis of optically active phenyl‑alkyl alcohols. This approach is increasingly relevant in the pharmaceutical industry where chirality influences biological activity.
Applications
Fragrance and Flavor Industry
Many C11H14O2 compounds serve as fragrance ingredients due to their pleasant aromatic profiles. Phenylacetate derivatives, for instance, emit sweet, fruity scents reminiscent of apples or strawberries. These molecules are incorporated into perfumery formulations at concentrations ranging from 0.01 % to 2 %, depending on the desired intensity and volatility.
Pharmaceutical Intermediates
Intermediate compounds such as 4-phenyl-2-butanol are key building blocks for the synthesis of active pharmaceutical ingredients (APIs). Their functional groups allow further derivatization into amides, ethers, or heterocyclic systems. The presence of the phenyl ring enhances metabolic stability, a desirable property in drug design.
Agrochemicals
Some esters derived from C11H14O2 have been evaluated for pesticidal activity. For example, phenylacetate derivatives have shown moderate insecticidal properties against aphids and moths. Their low water solubility can be advantageous for controlled‑release formulations, reducing the frequency of application in agricultural settings.
Material Science
Functionalized alcohols and acids serve as monomers in polymer chemistry. Polyesters synthesized from diacid and diol precursors that contain aromatic moieties derived from C11H14O2 exhibit enhanced thermal stability and mechanical strength. These materials find use in high‑performance composites for aerospace and automotive applications.
Analytical Standards
Pure C11H14O2 compounds are employed as reference standards in chromatographic and spectroscopic analyses. Their well‑defined melting points and spectroscopic fingerprints enable calibration of analytical instruments, ensuring accurate identification of unknown samples in environmental monitoring or quality control labs.
Biological and Pharmacological Activity
Enzyme Inhibition
Phenylacetate analogues have been reported to inhibit acetyl‑CoA carboxylase, an enzyme involved in fatty acid biosynthesis. In vitro studies demonstrate IC₅₀ values in the micromolar range, suggesting potential therapeutic applications in metabolic disorders. However, further investigations are needed to assess bioavailability and toxicity.
Neuropharmacology
Some aromatic ketone isomers display affinity for GABA_A receptors, modulating inhibitory neurotransmission. Their activity is comparable to that of known sedatives, albeit with lower potency. Research on these compounds focuses on structure‑activity relationships to optimize binding and reduce off‑target effects.
Antimicrobial Properties
Low‑molecular‑weight phenolic esters can disrupt bacterial cell membranes, exhibiting antibacterial activity against Gram‑positive strains. Minimal inhibitory concentrations (MICs) for certain C11H14O2 esters range from 50 to 200 µg/mL, indicating moderate potency. The mechanism involves interaction with membrane lipids, leading to increased permeability.
Plant Signaling
Some isomers act as plant volatiles, influencing insect behavior and plant–plant communication. For example, 3-phenyl-3-hydroxybutanoic acid has been detected in floral scents that attract pollinators. Understanding such signaling pathways can inform the development of bioinspired pest management strategies.
Pharmacokinetics and Toxicology
In animal models, C11H14O2 compounds exhibit moderate oral bioavailability, with half‑lives ranging from 1.5 to 4 hours depending on the functional group. Toxicological studies reveal low acute toxicity at doses up to 500 mg/kg, but chronic exposure can lead to hepatic enzyme induction. Safety assessments continue to refine acceptable exposure limits.
Environmental and Safety Considerations
Stability and Degradation
Most C11H14O2 isomers are chemically stable under ambient conditions. However, exposure to strong oxidants or prolonged UV irradiation can lead to degradation, producing carboxylic acids or aldehydes. In aqueous environments, esters hydrolyze slowly, yielding phenolic alcohols and acids that may be further metabolized by microorganisms.
Ecotoxicity
Bioassays using Daphnia magna and algae indicate that certain phenylacetate derivatives exhibit low acute toxicity, with LC₅₀ values above 200 µg/L. Chronic toxicity studies show no significant reproductive effects in fish species up to 100 µg/L. Nevertheless, monitoring of these compounds in aquatic systems remains advisable, especially in regions with high industrial use.
Handling and Exposure
These chemicals are generally handled under standard laboratory safety protocols. Protective gloves and eye protection are recommended to prevent skin and eye irritation. Inhalation of vapors should be avoided, and adequate ventilation is necessary when performing reactions that generate flammable or toxic byproducts.
Regulatory Restrictions
While most C11H14O2 compounds are not listed under major global chemical registries, certain derivatives may fall under specific regulatory frameworks if used in large volumes. For example, aromatic esters with potential endocrine‑disrupting activity are monitored by the European Union’s REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) programme, requiring safety data sheets (SDS) and risk assessments for commercial products.
Waste Management
Reaction wastes containing C11H14O2 isomers should be collected in designated organic waste containers. Neutralization of acidic or basic byproducts is essential before disposal to prevent corrosion of waste containers. Proper segregation of chemical waste streams facilitates compliance with environmental protection standards.
Conclusion
The molecular formula C₁₁H₁₄O₂ encapsulates a versatile class of organic compounds encompassing aromatic esters, ketones, alcohols, and acids. Their physical properties - ranging from moderate lipophilicity to hydrogen‑bonding capacities - underpin a wide array of industrial and scientific uses. Advances in synthetic methodologies, including catalytic, biocatalytic, and coupling strategies, enable efficient production of both racemic and chiral isomers. Applications across fragrance, pharmaceuticals, agrochemicals, materials, and analytical sciences underscore the importance of these molecules. Continued research into their biological activities and environmental impacts will further clarify their roles and inform responsible usage. As the demand for fine chemicals grows, understanding the full scope of C11H14O₂ compounds remains essential for chemists, toxicologists, and regulators alike.
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