QUINOLINE

Quinoline is a nitrogen-containing heteroaromatic compound used as an intermediate and functional additive in chemical manufacturing, dyes, pharmaceuticals, corrosion inhibitor chemistry, and specialty solvents.
Quinoline has strong solvency for many organic compounds and can act as a basic organic reagent, and Quinoline is often used as a building block for quinoline derivatives with tailored performance.
Quinoline must be handled with strict industrial hygiene because Quinoline is toxic, can be absorbed through skin, and Quinoline is associated with serious health hazards, so Quinoline use requires exposure controls, PPE, and compliance with applicable regulations.

CAS Number: 91-22-5
EC Number: 202-049-5
Molecular Formula: C9H7N
Molecular Weight: 129.16 g/mol

Synonyms: Quinoline, 1-Azanaphthalene (common naming), Benzopyridine (common naming), Quinoline Base, Quinoline Heteroaromatic, Quinoline Solvent, 91-22-5 Quinoline, Quinoline Intermediate, Quinoline Reagent, Quinoline Chemical, Quinoline Aromatic Amine, Quinoline Technical Grade, Quinoline, QUINOLINE, 1-Azanaphthalene, 1-azanaphthalene, Benzopyridine, benzo[b]pyridine (structural synonym), Benzo[b]pyridine, Benzo[b]pyridine (quinoline), Quinoleine (spelling variant), Chinoline (older spelling), Quinolina (variant), Quinoline Base (common wording), Quinoline (coal-tar base) (historical), Quinoline (aromatic heterocycle), Quinoline heteroaromatic, Quinoline ring system, Quinoline Reagent, Quinoline Analytical Grade, Quinoline Laboratory Grade, Quinoline Technical Grade, Quinoline Industrial Grade, Quinoline High Purity, Quinoline 98%, Quinoline 99%, Quinoline (CAS 91-22-5), CAS 91-22-5, Quinoline (C9H7N), C9H7N, Quinoline (EC 202-051-6) (common listing), EC 202-051-6, Quinoline (EINECS 202-051-6), Quinoline Liquid, Quinoline Oil (common wording), Quinoline Solvent (use context), Quinoline Intermediate, Quinoline Chemical Intermediate, Quinoline for synthesis

APPLICATIONS

Quinoline is used as a chemical intermediate in the manufacture of pharmaceuticals.
Quinoline is used as a heteroaromatic building block for synthesizing quinoline-based active ingredients.
Quinoline supports medicinal chemistry programs that explore nitrogen-containing ring systems.

Quinoline is used in production of antimalarial-related research compounds and analog screening libraries.
Quinoline is used to build quinoline-core molecules for SAR studies in drug discovery.
Quinoline helps enable synthesis of substituted quinolines via functionalization reactions.

Quinoline is used as an intermediate in dye and pigment manufacturing.
Quinoline supports synthesis of quinoline dyes used for textile and leather coloration.
Quinoline helps produce colorants where heteroaromatic structures improve shade and fastness.

Quinoline is used in manufacturing of specialty fine chemicals that require fused aromatic nitrogen rings.
Quinoline supports production of intermediates for fragrances, additives, and performance chemicals.
Quinoline helps create nitrogen-containing aromatic scaffolds for downstream chemistry.

Quinoline is used as a solvent in selected industrial processes due to its polarity and aromatic character.
Quinoline supports dissolution of certain resins, oils, and organic solids in niche applications.
Quinoline helps provide a high-boiling reaction medium for temperature-demanding processes.

Quinoline is used as a reaction solvent in organic synthesis for specific transformations.
Quinoline supports base-like or coordinating behavior in certain catalytic systems.
Quinoline helps improve solubility of aromatic substrates during synthesis steps.

Quinoline is used in corrosion inhibition research, especially for metal surfaces in acidic environments.
Quinoline supports development of inhibitor packages by adsorbing on metal surfaces in some systems.
Quinoline helps reduce corrosion rate in controlled laboratory corrosion tests.

Quinoline is used as an intermediate in dye manufacturing to produce quinoline-based colorants and pigments.
Quinoline is incorporated into synthesis routes for quinoline dyes used in textiles and specialty inks.
Quinoline is used in pigment intermediates where heteroaromatic structure supports chromophore design.

Quinoline is used as an intermediate in pharmaceutical manufacturing to build quinoline-containing active ingredients and intermediates.
Quinoline is incorporated into medicinal chemistry routes to develop antimalarial and antimicrobial scaffold derivatives.
Quinoline is used in fine chemical synthesis where quinoline ring systems provide biological activity or functional properties.

Quinoline is used in agrochemical synthesis as a building block for herbicide and pesticide intermediates in compatible routes.
Quinoline is incorporated into specialty crop protection intermediates where heteroaromatic chemistry is required.
Quinoline is used in chemical R&D to generate quinoline derivatives with specific performance properties.

Quinoline is used as a solvent and base in organic synthesis, especially at elevated temperatures due to Quinoline’s relatively high boiling point.
Quinoline is incorporated into reactions where a basic aromatic solvent improves solubility of reactants and supports reaction kinetics.
Quinoline is used in condensation and cyclization chemistry where Quinoline can serve as a solvent and acid scavenger.

Quinoline is used in corrosion inhibitor chemistry as a component or intermediate for producing metal-protective additives.
Quinoline is incorporated into inhibitor packages where nitrogen heterocycles improve adsorption on metal surfaces.
Quinoline is used in refinery and industrial systems research where corrosion control additives are evaluated.

Quinoline is used in rubber and polymer chemical manufacturing as an intermediate for antioxidants and stabilizer derivatives in selected chemistries.
Quinoline is incorporated into stabilization chemistry where heteroaromatic structures support radical scavenging and durability.
Quinoline is used in specialty additive synthesis where performance is built into a quinoline-derived structure.

Quinoline is used in analytical chemistry as a reference compound and in method development for heteroaromatic detection and quantification.
Quinoline is incorporated into calibration and spiking solutions for chromatographic testing.
Quinoline is used in environmental analysis to study nitrogen heteroaromatic contaminants and their fate.

Quinoline is used in research and teaching laboratories to demonstrate heteroaromatic chemistry, basicity, and aromatic substitution behavior.
Quinoline is incorporated into synthesis demonstrations under controlled, supervised conditions with proper ventilation.
Quinoline is valued because Quinoline provides a versatile heteroaromatic scaffold and solvent properties for diverse chemical manufacturing routes.

DESCRIPTION

Quinoline is a fused-ring heteroaromatic compound consisting of a benzene ring fused to a pyridine ring.
Quinoline is typically a colorless to pale yellow liquid that can darken on storage due to oxidation or impurities.
Quinoline has a strong characteristic odor and is considered a basic nitrogen-containing aromatic compound.

Quinoline has limited solubility in water but dissolves well in many organic solvents.
Quinoline has a relatively high boiling point compared with many simple aromatic solvents.
Quinoline can act as a weak base due to the lone pair on the ring nitrogen.

Quinoline is a fused aromatic ring system containing one nitrogen atom, and Quinoline is structurally related to naphthalene with a pyridine-like nitrogen that gives Quinoline basic character.
Quinoline is typically a colorless to pale yellow liquid that can darken on storage due to oxidation and impurities, and Quinoline has a strong characteristic odor.
Quinoline has moderate water solubility and high solubility in many organic solvents, and Quinoline is often used where strong solvency and high boiling point are beneficial.

Quinoline can form salts with acids, and Quinoline salts may be used in synthesis and purification steps.
Quinoline can be present as an impurity in coal tar streams, and industrial quinoline is often obtained and purified from such sources or by synthetic routes.
Quinoline is hazardous, and Quinoline exposure must be minimized using closed handling, ventilation, and strict PPE due to toxicity and potential long-term health risks.

Quinoline should be stored in tightly closed containers in a cool, well-ventilated place away from oxidizers and strong acids.
Quinoline should be protected from light and air where practical to reduce discoloration and degradation.
Quinoline waste should be collected as hazardous organic waste and disposed of according to local regulations and facility procedures.

PROPERTIES

Chemical Formula: C9H7N
Molecular Weight: 129.16 g/mol
Common Name: Quinoline
Chemical Type: Nitrogen heteroaromatic compound (benzopyridine)
Appearance: Colorless to pale yellow liquid; may darken on storage
Odor: Strong characteristic odor
Solubility: Slightly soluble in water; soluble in many organic solvents
Boiling Point: ~237–240°C (typical)
Melting Point: ~-15°C (typical)
Flash Point: ~100°C (typical; combustible)
Density: ~1.09 g/cm³ (typical)
Basicity: Weak base; forms salts with acids
Stability: Stable under recommended storage; avoid strong oxidizers and prolonged air exposure
Health Considerations: Toxic; possible serious chronic hazard; strict exposure control required
Storage Temperature: 15–25°C, tightly closed, well ventilated
Shelf Life: Typically 24–36 months in original sealed packaging (supplier dependent)

FIRST AID

Inhalation:
Move to fresh air immediately if vapors are inhaled.
Seek medical attention promptly if symptoms such as headache, dizziness, nausea, or respiratory irritation occur.
Keep the exposed person warm and at rest and monitor for delayed effects.

Skin Contact:
Remove contaminated clothing immediately and wash skin thoroughly with soap and water.
Seek medical attention if irritation occurs or if significant exposure happened because skin absorption can occur.
Wash contaminated clothing before reuse or dispose of it appropriately.

Eye Contact:
Rinse cautiously with water for several minutes.
Remove contact lenses if present and easy to do, then continue rinsing.
Seek medical attention promptly if irritation persists.

Ingestion:
Rinse mouth with water and seek immediate medical attention.
Do not induce vomiting unless directed by medical personnel.
Never give anything by mouth to an unconscious person.

Note to Physicians:
Treat symptomatically.
Consider systemic toxicity and monitor vital signs after significant exposure.
Provide supportive care based on exposure route and symptoms.

HANDLING AND STORAGE

Handling:
Use appropriate PPE including chemical-resistant gloves, goggles or face shield, and protective clothing.
Avoid breathing vapors and avoid skin contact due to absorption risk.
Use only in well-controlled industrial or laboratory environments with strict hygiene practices.

Ventilation:
Use local exhaust ventilation at points of transfer and mixing.
Use closed transfer systems where possible to reduce vapor release.
Avoid confined spaces without adequate airflow and exposure monitoring.

Storage:
Store in tightly closed containers in a cool, dry, well-ventilated place.
Keep away from oxidizers, strong acids, and ignition sources.
Protect from light and minimize air exposure to reduce discoloration and degradation.

Spill and Leak Procedures:
Evacuate area as needed and ensure good ventilation.
Contain spill and absorb with inert material, and collect into suitable containers for hazardous waste disposal.
Prevent entry into drains and waterways and follow site emergency procedures.

Handling Precautions:
Implement exposure monitoring and strict PPE selection due to toxicity and skin absorption potential.
Use compatible materials of construction and avoid reactive incompatibilities with oxidizers and strong acids.
Rotate stock using FIFO practices and keep containers sealed to maintain quality and reduce oxidation-related discoloration.