hexane
Enable an AI agent to identify a hexane material, assess whether its composition and condition suit an intended use, and determine which handling or disposition actions are justified.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to identify a hexane material, assess whether its composition and condition suit an intended use, and determine which handling or disposition actions are justified.
Hexane is the C6 saturated acyclic hydrocarbon C6H14 whose defined chemical species is unbranched n-hexane (CAS 110-54-3), while industrial "hexane" or "hexanes" is a petroleum C6 cut of mixed isomers whose n-hexane fraction, not the cut as a whole, determines γ-diketone neurotoxicity, CLP classification and food-residue limits.
It can be Resolve or flag whether a labelled material is n-hexane, another isomer or a commercial mixture.; Request appropriate identity, composition, water or residue testing when evidence is insufficient.; Accept, restrict or quarantine material against the requirements of a specified solvent use.; Evaluate a proposed transfer or use against applicable exposure, ignition and compatibility controls.; Detect when evaporation, contamination or recovery invalidates an earlier material assessment.; Route spent or rejected material for assessed recovery or an applicable waste pathway..
Distinguishing features
Check molecular identity: a pure hexane isomer has formula C6H14; cyclohexane has formula C6H12 and belongs to a different chemical identity.
Check molecular connectivity or an appropriately interpreted analytical identification: n-hexane has an unbranched six-carbon chain, whereas other C6H14 isomers are branched.
Check composition evidence: a commercial product labelled hexanes may be a mixture and must not be treated as pure n-hexane solely from its name.
Compare a measured boiling profile and other identity measurements against the declared composition at stated conditions; these support identification but do not uniquely establish it.
Check supplier identifiers against the actual product specification and batch analysis; appearance as a clear liquid is insufficient to distinguish hexane from similar solvents.
Scope
+ Chemical identity and the interpretation of hexane on supplier labels and analytical records
+ Isomer composition, n-hexane fraction, impurities and declared grade
+ Physical condition and changes caused by storage, evaporation or contamination
+ Suitability for a specified solvent or other material use
+ Material-specific exposure, ignition, compatibility and disposal constraints
- Independent models of other solvents, including cyclohexane and heptane
- Design and operating procedures of extraction, chromatography or manufacturing processes
- Design and certification of containers, ventilation systems and electrical equipment
- Clinical diagnosis or treatment of people exposed to solvents
- Organisation-wide chemical inventory, transport and waste-management systems
Characteristics
- Declared chemical identity
- n-hexane | specified other C6H14 isomer | commercial mixture | unresolved Prevents a common name from silently substituting for verified molecular or mixture identity.
- Identity evidence
- Links to label, supplier specification, safety data sheet and analytical identification, with applicability to the material Allows the agent to distinguish a supplier declaration from independently supported identity.
- Isomer and component composition
- Component fractions in mass %, mole % or volume %, with basis, method and uncertainty Composition affects solvent behaviour, volatility and the interpretation of hazard information.
- n-Hexane content
- Mass % or another explicitly stated fraction basis, with detection limit if not detected Makes the amount of n-hexane explicit when evaluating mixtures and their applicable handling constraints.
- Grade and specification
- Supplier grade linked to explicit acceptance criteria and intended application Grade names alone do not establish suitability for a particular analytical or production use.
- Water and relevant impurities
- Water in mg/kg; named impurities in mg/kg or %; method and reporting limits stated Contamination can make otherwise correctly identified hexane unsuitable for the intended use.
- Boiling behaviour
- Boiling point or distillation range in °C at stated pressure, with method Supports composition checks and assessment of evaporation or separation behaviour.
- Nonvolatile residue
- mg/L or mg/kg under a specified test method Residue can interfere with cleaning, extraction and analytical applications.
- Observed material condition
- Observation of clarity, colour, particles and separate phases, with temperature and observation time Visible changes can trigger quarantine or testing without being mistaken for definitive chemical identification.
- Handling assessment
- Composition-applicable hazard information linked to the proposed task and its controls An action decision requires both material evidence and the conditions of the proposed activity.
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.hexane
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 5 bundles · 9 layers · 16 findings · 26 questions.
Hexane identity and composition Establishes what the name hexane denotes for the material being assessed.
The unqualified name can obscure distinctions between n-hexane, branched isomers and commercial mixtures.
Name and molecular boundary
Separates the registry name from the chemical identity supported by evidence.
Declared versus established identity
The model must retain the declared name and the supported identity without treating them as automatically equivalent.
- Does hexane denote n-hexane, a specified C6H14 isomer or a commercial mixture in this record? definition
- Which label, specification or analytical evidence supports that interpretation for this material? provenance
- How are cyclohexane and other similarly named solvents excluded from this identity? boundary
Component profile
Records the composition needed to interpret a nominally pure material or mixture.
Isomer fractions and unidentified content
The model must expose n-hexane content, other reported components and the portion left analytically unresolved.
- What n-hexane fraction and other component fractions were measured, on which basis and by which method? measurement
- What unresolved components, detection limits or analytical limitations prevent a complete composition assessment? boundary
Hexane condition and change Tracks whether the current material still corresponds to its documented composition and quality.
Evaporation, contamination and reuse can undermine the applicability of an earlier certificate or assessment.
Current physical and analytical condition
Combines observations with tests relevant to contamination and identity consistency.
Condition evidence
The model must distinguish visible condition from measured evidence of water, impurities and boiling behaviour.
- Are colour changes, particles or separate phases observed, and at what temperature? measurement
- Do current water, impurity and boiling-profile measurements satisfy the material's declared specification? measurement
Storage and recovery history
Captures events that may change composition or introduce contaminants.
Changes requiring reassessment
The model must identify when opening, loss, mixing or recovery makes previous quality evidence insufficient.
- Has this material undergone prolonged opening, suspected evaporative loss, mixing or solvent recovery since its last applicable analysis? provenance
- Which changes require resampling, retesting or quarantine before further use? action
Hexane fitness for use Relates demonstrated material properties to the requirements of a specific application.
Correct identity does not establish that a hexane product is suitable for extraction, chromatography, cleaning or another intended use.
Application-specific quality
Makes solvent acceptance criteria explicit rather than relying on broad grade labels.
Grade-to-use match
The model must connect the intended solvent role to relevant limits for composition, water, residue and interfering impurities.
- What solvent role is intended, and which composition or quality limits determine acceptance for that role? definition
- Which applicable batch results demonstrate compliance with those limits, including residue or analytical background where relevant? measurement
Substitution and release
Determines when changes in product or composition require a fresh suitability decision.
Composition-sensitive use decision
The model must prevent unexamined substitution between pure n-hexane, commercial hexanes and recovered solvent.
- Would changing between n-hexane, commercial hexanes or recovered material alter the application's validated solvent requirements? boundary
- What evidence permits release for the intended use, and what restriction applies while that evidence is missing? action
Hexane handling and disposition Connects composition-applicable hazard evidence to proposed handling and end-of-use decisions.
Hexane decisions must account for volatile flammable solvent behaviour and the specific exposure implications of the actual composition.
Exposure, ignition and contact
Assesses whether proposed operations have controls appropriate to this product and task.
Task-specific handling basis
The model must associate the actual product and n-hexane content with applicable exposure, fire and material-compatibility evidence.
- Which current product-specific safety information supports the exposure, ignition and compatibility assessment? provenance
- What controls are required for the proposed quantity, temperature and transfer or use conditions? action
- What missing exposure or compatibility evidence prevents authorising the proposed operation? boundary
Spent material and recovery
Reassesses used hexane according to acquired contaminants and the intended disposition.
Disposition from actual composition
The model must retain use-derived contamination and recovery evidence rather than carrying forward the identity and quality assumptions of unused solvent.
- What substances may have entered the hexane during use, and which are measured or remain unknown? provenance
- What assessment supports recovery, reuse or the applicable waste route for this material in its present condition? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- n-Hexane (unbranched isomer; laboratory and analytical grades typically 95-99.5%)
- Commercial hexanes (petroleum C6 cut, n-hexane commonly 20-80%)
- Technical-grade hexane (about 50% n-hexane with isohexane and cyclohexane)
- Low-n-hexane hexane (mainly branched C6 isomers, <5% n-hexane; separate CLP index)
- 2-Methylpentane (isohexane)
- 3-Methylpentane
- 2,2-Dimethylbutane (neohexane)
- 2,3-Dimethylbutane
- Which of these kinds and varieties hold for the sense of hexane this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- CAS Registry Number - 110-54-3 - n-Hexane (unbranched isomer).
- CAS Registry Number - 92112-69-1 - Hexanes, mixture of isomers (PubChem synonym set).
- EC number (EINECS) - 203-777-6 - n-Hexane; ECHA InfoCard 100.003.435.
- CLP Index number - 601-037-00-0 - Harmonised classification for n-hexane in Annex VI to Regulation (EC) 1272/2008.
- CLP Index number - 601-007-00-7 - Hexane containing <5% n-hexane.
- PubChem CID - 8058 - n-Hexane.
- Wikidata - Q150440 - Item linked from PubChem CID 8058.
- ChEBI - CHEBI:29021 - n-Hexane.
- UN number - 1208 - Proper shipping name HEXANES; Class 3, packing group II.
- InChIKey - VLKZOEOYAKHREP-UHFFFAOYSA-N - Standard InChI: InChI=1S/C6H14/c1-3-5-6-4-2/h3-6H2,1-2H3.
- EPA CompTox / DSSTox - DTXSID0021917 - n-Hexane.
- UNII (FDA GSRS) - 2DDG612ED8 - n-Hexane.
- RTECS - MN9275000 - n-Hexane.
- Which of these identifiers and schemes hold for the sense of hexane this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- OSHA (US): PEL 500 ppm (1800 mg/m³) 8-hour TWA for n-hexane (still the legally binding workplace limit).
- NIOSH (US): REL 50 ppm (180 mg/m³) up to 10-hour TWA; IDLH 1100 ppm (10% of LEL).
- ACGIH: TLV-TWA 50 ppm for n-hexane, versus 500 ppm TWA for other hexane isomers - the isomer split is the practical occupational distinction.
- European Commission / SCOEL: indicative OEL 20 ppm (72 mg/m³) 8-hour TWA for n-hexane, adopted as the EU IOEL and used as the REACH worker DNEL in the German substance evaluation.
- ECHA / CLP (Regulation (EC) 1272/2008): n-hexane index 601-037-00-0, including Flam. Liq. 2 H225, Asp. Tox. 1 H304, Skin Irrit. 2 H315, STOT SE 3 H336, STOT RE 1 H372 (nervous system), Repr. 2 H361f, Aquatic Chronic 2 H411; low-n-hexane hexane is indexed separately as 601-007-00-7.
- REACH (Regulation (EC) 1907/2006): n-hexane identified under Article 57(f) as a substance of equivalent concern for probable serious effects on the nervous system after repeated exposure.
- US EPA IRIS: inhalation RfC 0.7 mg/m³ (0.2 ppm); carcinogenicity "inadequate information"; 1-day and 10-day drinking-water health advisories 10 mg/L and 4 mg/L (10-kg child); not a National Primary Drinking Water contaminant.
- US FDA: permitted extractant for specified food and colour additives, with residue restrictions, and in some indirect food-contact coatings.
- UN/ADR/IMDG/IATA: UN 1208 HEXANES, Class 3, packing group II.
- Health Canada WHMIS: B2 flammable liquid and D2A chronic toxicity (peripheral neuropathy); ingredient disclosure at 1.0%.
- Which of these standards and regulation hold for the sense of hexane this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Large-scale solvent extraction of edible vegetable oils from soybeans, peanuts, flaxseed and similar oilseeds; residual hexane in finished oils is a regulated food-contact issue.
- Formulating rubber cements, contact adhesives, inks, varnishes and lacquers, historically including shoe-industry glues that produced outbreaks of hexane neuropathy.
- Laboratory and chromatography solvent and reaction medium; analytical grades are sold as n-hexane, spectroscopic mixed hexanes, or "hexanes, mixture of isomers".
- Industrial degreasing and cleaning where a cheap C6 cut is enough and isomer purity is not required.
- Constituent of gasoline, heating fuels and naphtha; public exposure is mainly as a trace in evaporative hydrocarbon air.
- Pharmaceutical manufacturing solvent and polymer/rubber processing aid.
- Which of these real-world use hold for the sense of hexane this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Normal boiling point (n-hexane) - 68.5-69.1 - °C
- Melting / freezing point (n-hexane) - −96 to −94 - °C
- Liquid density (n-hexane, ~20 °C) - 0.659-0.661 - g/mL
- Closed-cup flash point - −26 to −22 - °C
- Vapour pressure at 20 °C - 16-17.6 - kPa
- Explosive / flammable limits in air - LEL 1.1-1.2; UEL 7.5-8.9 - vol %
- Water solubility (25 °C) - ~9.5 - mg/L
- n-Hexane mass fraction in commercial hexane - 20-80 (technical ~50; analytical 95-99.5; "low n-hexane" <5) - %
- Workplace air concentration (occupational limits, n-hexane) - EU IOEL 20; NIOSH/ACGIH 50; OSHA PEL 500 - ppm
- Air conversion factor - 1 ppm = 3.53 - mg/m³
- Which of these typical measurements hold for the sense of hexane this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Highly flammable liquid and vapour: closed-cup flash point around −23 °C, vapours heavier than air (density ~2.97), explosive mixtures at ambient temperature; autoignition ~225-234 °C, low enough to be reached by hot engine parts.
- Aspiration of liquid into the lung causes chemical pneumonitis (GHS H304).
- Chronic inhalation produces distal axonopathy (sensorimotor peripheral neuropathy: numbness, weakness, in severe cases paralysis) via the metabolite 2,5-hexanedione; documented in shoe and adhesive workers and in solvent abuse.
- Acute CNS depression: dizziness, headache, nausea; eye and respiratory irritation; repeated skin contact causes dermatitis by defatting.
- Co-exposure to other solvents, especially methyl ethyl ketone, potentiates the neuropathy; mixture OELs based on n-hexane alone can under-protect.
- Aquatic chronic toxicity (H411); spills to water and soil are environmental releases from extraction plants, fuel handling and solvent use.
- Empty drums and low-lying vapour clouds remain an ignition source after the liquid is gone.
- Which of these failure modes and hazards hold for the sense of hexane this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Naming: English trade usage often says "hexane" or "hexanes" for the mixed C6 cut and "n-hexane" for the linear isomer; French toxicology (INRS) treats hexane commercial as the mixture and reserves a separate entry for hexane <5% n-hexane; Italian Esani, Polish heksan, Dutch hexanen appear as synonyms.
- Occupational limits differ by more than an order of magnitude: EU IOEL 20 ppm, NIOSH/ACGIH 50 ppm, German DFG/AGS 50 ppm, OSHA PEL still 500 ppm.
- EU CLP drives demand for low-n-hexane grades (<5%) so that the mixture avoids n-hexane's STOT RE 1 and reproductive classification; US bulk solvent practice more often sells a mixed cut labelled hexane without that split.
- Edible-oil extraction is global, but residue enforcement and public debate are sharper in the EU (extraction-solvent rules and reported traces in oils, margarines and related foods) than under the FDA extractant permissions.
- Which of these regional variation hold for the sense of hexane this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Commercial hexanes (mixed C6 cut) - Same trade name, different composition: assay n-hexane by GC. The mixture's boiling range is broader (~49-69 °C across isomers) and its neuropathy risk scales with n-hexane content, not with total C6.
- Other hexane isomers (2-methylpentane, 3-methylpentane, dimethylbutanes) - Same formula C6H14 but branched; boiling points 49.7-63.3 °C versus ~68.7 °C for n-hexane. They are not metabolised to 2,5-hexanedione to the same extent; ACGIH TLV for "other hexane isomers" is 500 ppm versus 50 ppm for n-hexane.
- Cyclohexane - C6H12 saturated ring, not C6H14. Distinguish by molecular formula, boiling point (~81 °C vs ~69 °C) and GC; cyclohexane is a common impurity in commercial hexane and does not share the 2,5-hexanedione axonopathy pathway.
- Hexene / hexyne - Unsaturated C6 hydrocarbons (C6H12 / C6H10). Separate by unsaturation tests or GC-MS; Wikipedia flags both as not-to-be-confused names.
- n-Heptane - C7H16; boiling point ~98 °C versus ~69 °C. Used as a less neurotoxic hydrocarbon solvent substitute; confirm carbon number by GC.
- Petroleum ether / light naphtha - A boiling-range cut, not a C6 identity. Hexane may be a component; distinguish by specified boiling range and GC profile rather than by the name "hexane".
- Benzene - C6H6 aromatic, historically a co-contaminant of light petroleum solvents. Separate by GC or UV; benzene is a leukaemogen, n-hexane a γ-diketone neurotoxicant.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of hexane this model covers, and on what evidence? provenance
Sources
- Hexane - IUPAC name, identifiers (CAS, EC, PubChem, InChI, UN 1208), isomer table and boiling points, physical properties, and the commercial hexanes vs n-hexane distinction.
- Hexane | C6H14 | CID 8058 - Canonical identifiers (CAS 110-54-3, EC 203-777-6, InChIKey, mixed-hexanes CAS 92112-69-1, Wikidata Q150440) and transport/hazard crosswalks.
- Hexane (FT 113). Généralités - Fiche toxicologique - Commercial composition (20-80% n-hexane), technical vs analytical grades, low-n-hexane grade, CLP index numbers, physical constants, extraction-solvent use, and explosion limits.
- Toxicological Profile for n-Hexane - Chemical identity of n-hexane vs commercial hexanes, occupational peripheral neuropathy, and the 2025 ATSDR regulatory table (OSHA, NIOSH, EPA IRIS, FDA extractant use).
- n-Hexane: general information - Occurrence in crude oil and fuels, edible-oil extraction, adhesives, rubber and laboratory solvent uses, and typical exposure settings.
- NIOSH Pocket Guide to Chemical Hazards - n-Hexane - REL 50 ppm, OSHA PEL 500 ppm, IDLH 1100 ppm, conversion factor, flash point, LEL/UEL, and acute vs neuropathic symptoms.
What the second pass must settle
- Does the registry intend hexane to mean n-hexane specifically, all C6H14 isomers or commercial hexane products, and is an existing model already authoritative for any of that scope?
- Which authoritative identity references and analytical methods should establish the boundary between n-hexane, other isomers and commercial mixtures?
- Which intended applications need explicit acceptance limits for isomer composition, water, nonvolatile residue and trace impurities?
- Which product-specific and jurisdiction-specific sources govern exposure assessment, handling and waste decisions for the materials represented?
- What evidence and retesting criteria are sufficient to requalify stored, partially evaporated or recovered hexane for each intended use?