{
  "spore": "profile",
  "id": "methanol-heat-pipe-fluid",
  "spore_version": "0.2",
  "family": "alcohols",
  "name": "Methanol (heat pipe working fluid)",
  "role": "heat pipe working fluid",
  "category": "thermal-protection",
  "type": "multi-layer-insulation",
  "summary": "Methanol (CH3OH, CAS 67-56-1) is a liquid working fluid for heat pipes. NIST records a normal boiling point of 337.8 K and an enthalpy of vaporization of 37.6 kJ/mol at standard conditions. It is flammable: ICSC records a flash point of 9 °C, and NASA heat pipe reports found methanol incompatible with aluminium envelopes.\n",
  "best_for": "Moderate-temperature heat pipes with stainless steel or titanium walls, where ammonia is not used (NASA heat pipe reports)",
  "weakest_at": "Flammability and toxicity: low flash point and a toxic, flammable vapour (ICSC, NIOSH, PubChem)",
  "identity": {
    "formula": "CH3OH (also printed as CH4O on the NIST page)",
    "cas": "67-56-1",
    "designations": [],
    "source": "nist-webbook-methanol",
    "where": "Page header: Formula and CAS Registry Number"
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "thermal-control"
    ]
  },
  "properties": [
    {
      "benchmark": "boiling_point",
      "label": "Normal boiling point (NIST average)",
      "value": 337.8,
      "bound": "exact",
      "unit": "K",
      "scope": "material",
      "conditions": {
        "uncertainty": "plus or minus 0.3 K",
        "basis": "average of 154 out of 171 values compiled by NIST"
      },
      "method": "Average of literature values compiled by the NIST Thermodynamics Research Center",
      "status": "ground",
      "source": "nist-webbook-methanol",
      "where": "Phase change data, Tboil",
      "source_detail": {
        "title": "NIST Chemistry WebBook: Methyl Alcohol, phase change data and thermodynamic data",
        "url": "https://webbook.nist.gov/cgi/cbook.cgi?Mask=4&ID=C67561",
        "year": 2026,
        "kind": "database",
        "license": "U.S. Secretary of Commerce, NIST Standard Reference Data (cited, not reproduced)"
      }
    },
    {
      "benchmark": "boiling_point",
      "label": "Boiling point (Wikipedia infobox)",
      "value": 64.7,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "infobox value in degrees Celsius; the same cell also prints 337.8 K"
      },
      "method": "Infobox value compiled from the cited sources on the page",
      "status": "ground",
      "source": "wikipedia-methanol",
      "where": "Infobox, Boiling point",
      "source_detail": {
        "title": "Methanol (infobox properties, production and history)",
        "url": "https://en.wikipedia.org/wiki/Methanol",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point (Wikipedia infobox, kelvin)",
      "value": 175.6,
      "bound": "exact",
      "unit": "K",
      "scope": "material",
      "conditions": {
        "basis": "value printed in kelvin in the infobox"
      },
      "method": "Infobox value compiled from the cited sources on the page",
      "status": "ground",
      "source": "wikipedia-methanol",
      "where": "Infobox, Melting point",
      "source_detail": {
        "title": "Methanol (infobox properties, production and history)",
        "url": "https://en.wikipedia.org/wiki/Methanol",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "triple_point_temperature",
      "label": "Triple point temperature",
      "value": 175.5,
      "bound": "exact",
      "unit": "K",
      "scope": "material",
      "conditions": {
        "uncertainty": "plus or minus 0.5 K",
        "basis": "average of 8 values compiled by NIST"
      },
      "method": "Average of literature values compiled by the NIST Thermodynamics Research Center",
      "status": "ground",
      "source": "nist-webbook-methanol",
      "where": "Phase change data, Ttriple",
      "source_detail": {
        "title": "NIST Chemistry WebBook: Methyl Alcohol, phase change data and thermodynamic data",
        "url": "https://webbook.nist.gov/cgi/cbook.cgi?Mask=4&ID=C67561",
        "year": 2026,
        "kind": "database",
        "license": "U.S. Secretary of Commerce, NIST Standard Reference Data (cited, not reproduced)"
      }
    },
    {
      "benchmark": "critical_temperature",
      "label": "Critical temperature",
      "value": 513,
      "bound": "exact",
      "unit": "K",
      "scope": "material",
      "conditions": {
        "uncertainty": "plus or minus 1 K",
        "basis": "average of 27 out of 31 values compiled by NIST"
      },
      "method": "Average of literature values compiled by the NIST Thermodynamics Research Center",
      "status": "ground",
      "source": "nist-webbook-methanol",
      "where": "Phase change data, Tc",
      "source_detail": {
        "title": "NIST Chemistry WebBook: Methyl Alcohol, phase change data and thermodynamic data",
        "url": "https://webbook.nist.gov/cgi/cbook.cgi?Mask=4&ID=C67561",
        "year": 2026,
        "kind": "database",
        "license": "U.S. Secretary of Commerce, NIST Standard Reference Data (cited, not reproduced)"
      }
    },
    {
      "benchmark": "critical_pressure",
      "label": "Critical pressure",
      "value": 81,
      "bound": "exact",
      "unit": "bar",
      "scope": "material",
      "conditions": {
        "uncertainty": "plus or minus 1 bar",
        "basis": "average of 17 out of 20 values compiled by NIST"
      },
      "method": "Average of literature values compiled by the NIST Thermodynamics Research Center",
      "status": "ground",
      "source": "nist-webbook-methanol",
      "where": "Phase change data, Pc",
      "source_detail": {
        "title": "NIST Chemistry WebBook: Methyl Alcohol, phase change data and thermodynamic data",
        "url": "https://webbook.nist.gov/cgi/cbook.cgi?Mask=4&ID=C67561",
        "year": 2026,
        "kind": "database",
        "license": "U.S. Secretary of Commerce, NIST Standard Reference Data (cited, not reproduced)"
      }
    },
    {
      "benchmark": "critical_density",
      "label": "Critical density",
      "value": 8.51,
      "bound": "exact",
      "unit": "mol/l",
      "scope": "material",
      "conditions": {
        "uncertainty": "plus or minus 0.07 mol/l",
        "basis": "average of 7 values compiled by NIST"
      },
      "method": "Average of literature values compiled by the NIST Thermodynamics Research Center",
      "status": "ground",
      "source": "nist-webbook-methanol",
      "where": "Phase change data, critical density (rho c)",
      "source_detail": {
        "title": "NIST Chemistry WebBook: Methyl Alcohol, phase change data and thermodynamic data",
        "url": "https://webbook.nist.gov/cgi/cbook.cgi?Mask=4&ID=C67561",
        "year": 2026,
        "kind": "database",
        "license": "U.S. Secretary of Commerce, NIST Standard Reference Data (cited, not reproduced)"
      }
    },
    {
      "benchmark": "enthalpy_of_vaporization",
      "label": "Enthalpy of vaporization at standard conditions",
      "value": 37.6,
      "bound": "exact",
      "unit": "kJ/mol",
      "scope": "material",
      "conditions": {
        "uncertainty": "plus or minus 0.5 kJ/mol",
        "basis": "standard conditions; average of 11 out of 12 values compiled by NIST"
      },
      "method": "Average of literature values compiled by the NIST Thermodynamics Research Center",
      "status": "ground",
      "source": "nist-webbook-methanol",
      "where": "Phase change data, delta vap H degrees",
      "source_detail": {
        "title": "NIST Chemistry WebBook: Methyl Alcohol, phase change data and thermodynamic data",
        "url": "https://webbook.nist.gov/cgi/cbook.cgi?Mask=4&ID=C67561",
        "year": 2026,
        "kind": "database",
        "license": "U.S. Secretary of Commerce, NIST Standard Reference Data (cited, not reproduced)"
      }
    },
    {
      "benchmark": "enthalpy_of_vaporization",
      "label": "Enthalpy of vaporization near boiling",
      "value": 35.21,
      "bound": "exact",
      "unit": "kJ/mol",
      "scope": "material",
      "conditions": {
        "temperature": "337.7 K",
        "basis": "single value from the NIST enthalpy table, from Majer and Svoboda (1985)"
      },
      "method": "Value from a compiled enthalpy table",
      "status": "ground",
      "source": "nist-webbook-methanol",
      "where": "Enthalpy of vaporization table, first row",
      "source_detail": {
        "title": "NIST Chemistry WebBook: Methyl Alcohol, phase change data and thermodynamic data",
        "url": "https://webbook.nist.gov/cgi/cbook.cgi?Mask=4&ID=C67561",
        "year": 2026,
        "kind": "database",
        "license": "U.S. Secretary of Commerce, NIST Standard Reference Data (cited, not reproduced)"
      }
    },
    {
      "benchmark": "enthalpy_of_fusion",
      "label": "Enthalpy of fusion",
      "value": 3.18,
      "bound": "exact",
      "unit": "kJ/mol",
      "scope": "material",
      "conditions": {
        "temperature": "175.3 K",
        "reference": "Domalski and Hearing, 1996, as cited by NIST"
      },
      "method": "Value from a compiled enthalpy table",
      "status": "ground",
      "source": "nist-webbook-methanol",
      "where": "Enthalpy of fusion table, first row",
      "source_detail": {
        "title": "NIST Chemistry WebBook: Methyl Alcohol, phase change data and thermodynamic data",
        "url": "https://webbook.nist.gov/cgi/cbook.cgi?Mask=4&ID=C67561",
        "year": 2026,
        "kind": "database",
        "license": "U.S. Secretary of Commerce, NIST Standard Reference Data (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density (Wikipedia infobox)",
      "value": 0.792,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "temperature": "not printed on the page"
      },
      "method": "Infobox value; the page gives no temperature",
      "status": "ground",
      "source": "wikipedia-methanol",
      "where": "Infobox, Density",
      "source_detail": {
        "title": "Methanol (infobox properties, production and history)",
        "url": "https://en.wikipedia.org/wiki/Methanol",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "viscosity",
      "label": "Viscosity (Wikipedia infobox)",
      "value": 0.545,
      "bound": "exact",
      "unit": "mPa·s",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C",
        "basis": "the page labels it Viscosity and does not say dynamic"
      },
      "method": "Infobox value",
      "status": "ground",
      "source": "wikipedia-methanol",
      "where": "Infobox, Viscosity",
      "source_detail": {
        "title": "Methanol (infobox properties, production and history)",
        "url": "https://en.wikipedia.org/wiki/Methanol",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "flash_point",
      "label": "Flash point (ICSC, closed cup)",
      "value": 9,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "ICSC prints the method as c.c., which means closed cup"
      },
      "method": "Value printed in the ICSC chemical safety card",
      "status": "ground",
      "source": "icsc-0057",
      "where": "Flash point line",
      "source_detail": {
        "title": "ICSC 0057: Methanol (International Chemical Safety Card)",
        "id": "ICSC 0057",
        "url": "https://www.inchem.org/documents/icsc/icsc/eics0057.htm",
        "year": 2026,
        "kind": "handbook",
        "license": "ILO and WHO safety card (cited, not reproduced)"
      }
    },
    {
      "benchmark": "flash_point",
      "label": "Flash point (NIOSH)",
      "value": 52,
      "bound": "exact",
      "unit": "°F",
      "scope": "material",
      "conditions": {
        "basis": "flash point field as printed; test method not stated on the page"
      },
      "method": "Value printed in the NIOSH Pocket Guide entry",
      "status": "ground",
      "source": "niosh-npg-methanol",
      "where": "Flash point field",
      "source_detail": {
        "title": "NIOSH Pocket Guide to Chemical Hazards: Methanol",
        "id": "NPG 0397; RTECS PC1400000",
        "url": "https://www.cdc.gov/niosh/npg/npgd0397.html",
        "year": 2026,
        "kind": "handbook",
        "license": "U.S. government work (cited, not reproduced)"
      }
    },
    {
      "benchmark": "flash_point",
      "label": "Flash point range (Wikipedia infobox)",
      "value": 11,
      "value_high": 12,
      "bound": "range",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "range printed in the infobox"
      },
      "method": "Infobox value compiled from the cited sources on the page",
      "status": "ground",
      "source": "wikipedia-methanol",
      "where": "Infobox, Flash point",
      "source_detail": {
        "title": "Methanol (infobox properties, production and history)",
        "url": "https://en.wikipedia.org/wiki/Methanol",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "autoignition_temperature",
      "label": "Auto-ignition temperature (ICSC)",
      "value": 440,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "ICSC value as printed"
      },
      "method": "Value printed in the ICSC chemical safety card",
      "status": "ground",
      "source": "icsc-0057",
      "where": "Auto-ignition temperature line",
      "source_detail": {
        "title": "ICSC 0057: Methanol (International Chemical Safety Card)",
        "id": "ICSC 0057",
        "url": "https://www.inchem.org/documents/icsc/icsc/eics0057.htm",
        "year": 2026,
        "kind": "handbook",
        "license": "ILO and WHO safety card (cited, not reproduced)"
      }
    },
    {
      "benchmark": "autoignition_temperature",
      "label": "Auto-ignition temperature (Wikipedia infobox)",
      "value": 470,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "one of two values printed in the infobox, cited to a different source"
      },
      "method": "Infobox value compiled from the cited sources on the page",
      "status": "ground",
      "note": "The infobox prints a second, lower autoignition value cited to another source; it is not recorded here.",
      "source": "wikipedia-methanol",
      "where": "Infobox, Autoignition temperature",
      "source_detail": {
        "title": "Methanol (infobox properties, production and history)",
        "url": "https://en.wikipedia.org/wiki/Methanol",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "explosive_limits",
      "label": "Explosive limits in air (NIOSH)",
      "value": 6,
      "value_high": 36,
      "bound": "range",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "basis": "lower explosive limit 6.0% and upper explosive limit 36% as printed by NIOSH"
      },
      "method": "Values printed in the NIOSH Pocket Guide entry",
      "status": "ground",
      "source": "niosh-npg-methanol",
      "where": "Explosive limits field",
      "source_detail": {
        "title": "NIOSH Pocket Guide to Chemical Hazards: Methanol",
        "id": "NPG 0397; RTECS PC1400000",
        "url": "https://www.cdc.gov/niosh/npg/npgd0397.html",
        "year": 2026,
        "kind": "handbook",
        "license": "U.S. government work (cited, not reproduced)"
      }
    },
    {
      "benchmark": "explosive_limits",
      "label": "Explosive limits in air (ICSC)",
      "value": 6,
      "value_high": 50,
      "bound": "range",
      "unit": "vol% in air",
      "scope": "material",
      "conditions": {
        "basis": "ICSC prints the range as vol% in air without labelling lower and upper limits"
      },
      "method": "Value printed in the ICSC chemical safety card",
      "status": "ground",
      "note": "ICSC's upper value differs from the upper limit printed by NIOSH and Wikipedia; both are recorded.",
      "source": "icsc-0057",
      "where": "Explosive limits line",
      "source_detail": {
        "title": "ICSC 0057: Methanol (International Chemical Safety Card)",
        "id": "ICSC 0057",
        "url": "https://www.inchem.org/documents/icsc/icsc/eics0057.htm",
        "year": 2026,
        "kind": "handbook",
        "license": "ILO and WHO safety card (cited, not reproduced)"
      }
    },
    {
      "benchmark": "vapor_pressure",
      "label": "Vapour pressure (ICSC)",
      "value": 12.9,
      "bound": "exact",
      "unit": "kPa",
      "scope": "material",
      "conditions": {
        "temperature": "20 °C"
      },
      "method": "Value printed in the ICSC chemical safety card",
      "status": "ground",
      "source": "icsc-0057",
      "where": "Vapour pressure line",
      "source_detail": {
        "title": "ICSC 0057: Methanol (International Chemical Safety Card)",
        "id": "ICSC 0057",
        "url": "https://www.inchem.org/documents/icsc/icsc/eics0057.htm",
        "year": 2026,
        "kind": "handbook",
        "license": "ILO and WHO safety card (cited, not reproduced)"
      }
    },
    {
      "benchmark": "occupational_exposure_limit",
      "label": "NIOSH recommended exposure limit (TWA)",
      "value": 200,
      "bound": "exact",
      "unit": "ppm",
      "scope": "material",
      "conditions": {
        "basis": "time-weighted average, as printed; skin absorption also flagged"
      },
      "method": "Value printed in the NIOSH Pocket Guide entry",
      "status": "ground",
      "source": "niosh-npg-methanol",
      "where": "Exposure limits, NIOSH REL",
      "source_detail": {
        "title": "NIOSH Pocket Guide to Chemical Hazards: Methanol",
        "id": "NPG 0397; RTECS PC1400000",
        "url": "https://www.cdc.gov/niosh/npg/npgd0397.html",
        "year": 2026,
        "kind": "handbook",
        "license": "U.S. government work (cited, not reproduced)"
      }
    },
    {
      "benchmark": "idlh",
      "label": "Immediately dangerous to life or health (IDLH)",
      "value": 6000,
      "bound": "exact",
      "unit": "ppm",
      "scope": "material",
      "conditions": {
        "basis": "IDLH value as printed by NIOSH"
      },
      "method": "Value printed in the NIOSH Pocket Guide entry",
      "status": "ground",
      "source": "niosh-npg-methanol",
      "where": "Exposure limits, IDLH",
      "source_detail": {
        "title": "NIOSH Pocket Guide to Chemical Hazards: Methanol",
        "id": "NPG 0397; RTECS PC1400000",
        "url": "https://www.cdc.gov/niosh/npg/npgd0397.html",
        "year": 2026,
        "kind": "handbook",
        "license": "U.S. government work (cited, not reproduced)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Aluminium envelope and wick with methanol charge",
      "headline": "Methanol and aluminium heat pipes are incompatible and generate gas.",
      "effect": "A NASA heat pipe manufacturing study says methanol and aluminium heat pipe combinations are incompatible, resulting in gas generation, and cites an earlier reference for this. The study's own methanol charging results were inconclusive because gas formed during charging.",
      "rating": "severe",
      "conditions": {
        "basis": "statement in the life-test discussion of the report; no test duration or gas volume is given in the passage"
      },
      "source": "nasa-19750002275",
      "where": "Section 3, life-test results text, printed page 3-23"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "PubChem's ECHA aggregated data lists methanol as a highly flammable liquid and vapour, toxic if swallowed, toxic in contact with skin, toxic if inhaled, and causing damage to organs.",
        "ghs": [
          "H225",
          "H301",
          "H311",
          "H331",
          "H370"
        ],
        "source": "pubchem-methanol",
        "where": "GHS Classification, ECHA aggregated set"
      },
      {
        "text": "NIOSH classes methanol as a Class IB flammable liquid and describes it as a colourless liquid with a pungent odour.",
        "ghs": [],
        "source": "niosh-npg-methanol",
        "where": "Hazard classification and physical description fields"
      },
      {
        "text": "ICSC states that the substance is irritating to the eyes, skin and respiratory tract, and that a harmful contamination of the air can be reached quickly on evaporation at ordinary room temperature.",
        "ghs": [],
        "source": "icsc-0057",
        "where": "Short-term effects; Inhalation risk"
      }
    ],
    "failure_risks": [
      {
        "mode": "Gas generation in an aluminium heat pipe",
        "trigger": "Methanol charged into an aluminium envelope and wick",
        "consequence": "Gas forms inside the pipe. The NASA report calls the methanol and aluminium combination incompatible, so the pipe cannot be relied on to work as designed.",
        "severity": "high",
        "source": "nasa-19750002275",
        "where": "Section 3, life-test results text, printed page 3-23"
      },
      {
        "mode": "Vapour ignition after a leak",
        "trigger": "Leak or rupture that releases methanol vapour into air",
        "consequence": "Vapour mixes well with air and explosive mixtures form easily (ICSC). The flash point is low (see the flash point properties).",
        "severity": "high",
        "source": "icsc-0057",
        "where": "Physical dangers"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "Keep methanol away from strong oxidizers. NIOSH lists strong oxidizers as the incompatibility.",
        "source": "niosh-npg-methanol",
        "where": "Incompatibilities and reactivities"
      },
      {
        "text": "Treat any leak as a fire risk, because the vapour forms explosive mixtures with air easily.",
        "source": "icsc-0057",
        "where": "Physical dangers"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "thermal-control",
      "device": "Gas-loaded variable-conductance heat pipe for temperature control",
      "example": "A NASA report describes a methanol heat pipe that uses nitrogen gas for temperature control, which was constructed and tested with the heat source near ambient temperature. The OCR scan of the abstract is letter-spaced, so this is paraphrased.",
      "source": "nasa-19730022152",
      "where": "Abstract"
    },
    {
      "application": "thermal-control",
      "device": "Dual-slot heat pipe radiator for solar dynamic heat rejection",
      "example": "A NASA study recommended stainless steel/methanol or titanium/methanol dual-slot heat pipe radiator systems as the baseline configuration for the CBC solar dynamic heat rejection system.",
      "source": "nasa-19880013798",
      "where": "Task 1 results, paragraph on the CBC solar dynamic heat rejection system"
    },
    {
      "application": "thermal-control",
      "device": "Moderate-temperature aluminium and stainless steel heat pipes",
      "example": "A NASA manufacturing study covered moderate-temperature aluminium and stainless steel heat pipes that used ammonia, Freon-21 or methanol as the working fluid.",
      "source": "nasa-19750002275",
      "where": "Introduction, study scope"
    }
  ],
  "supply": [
    {
      "subject": "Methanol, industrial synthesis",
      "producers": [],
      "critical_lists": [],
      "substitutes": [],
      "source": "wikipedia-methanol",
      "where": "Production section; Introduction"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "NIST Chemistry WebBook: Methyl Alcohol (CAS 67-56-1), phase change data",
      "type": "database",
      "url": "https://webbook.nist.gov/cgi/cbook.cgi?Mask=4&ID=C67561",
      "year": 2026
    },
    {
      "title": "PubChem REST view: Methanol (CID 887), GHS Classification",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/887/JSON?heading=GHS+Classification",
      "year": 2026
    },
    {
      "title": "NIOSH Pocket Guide to Chemical Hazards: Methanol (NPG 0397)",
      "type": "database",
      "url": "https://www.cdc.gov/niosh/npg/npgd0397.html",
      "year": 2026
    },
    {
      "title": "ICSC 0057: Methanol (International Chemical Safety Card)",
      "type": "database",
      "url": "https://www.inchem.org/documents/icsc/icsc/eics0057.htm",
      "year": 2026
    },
    {
      "title": "NASA heat pipe manufacturing study (NTRS 19750002275)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/citations/19750002275",
      "year": 1975
    },
    {
      "title": "NASA gas-loaded variable-conductance heat pipe report (NTRS 19730022152)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/citations/19730022152",
      "year": 1973
    },
    {
      "title": "NASA solar dynamic heat rejection report, Task 1 (NTRS 19880013798)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/citations/19880013798",
      "year": 1988
    }
  ],
  "gaps": [
    "Global production volume and producer country shares were not found in a page read in this run. Wikipedia gives a production volume without a year and no country shares.",
    "Atomic weights for the recipe parts were not taken from a fetched page, so the recipe lists atom counts only.",
    "Copper wall compatibility over a stated temperature range was not found. The planner's claim that methanol is the standard fluid for copper heat pipes, with ammonia incompatible with copper, is unsourced here. NASA report 19750002275 has a copper-bronze test table with methanol, but its layout could not be read reliably, so no value was recorded.",
    "Flash point differs between sources: ICSC gives a closed-cup value, Wikipedia gives a range and NIOSH gives a Fahrenheit value. All three are recorded and none is preferred.",
    "Explosive limits differ: NIOSH and Wikipedia give an upper limit of 36%, while ICSC gives 50 vol% in air. Both are recorded.",
    "Liquid thermal conductivity, surface tension, latent heat at heat pipe operating temperatures and the heat pipe operating limits were not found in a page read in this run.",
    "Wikipedia gives density without a temperature, and no temperature-dependent density table was read.",
    "No flight or space-qualification result for methanol heat pipes was found. The NASA reports read here are ground development and study documents.",
    "Radiation and atomic oxygen effects on methanol and its heat pipe walls were not looked up.",
    "The PubChem page read here did not print the CAS number; the CAS number is taken from the NIST and NIOSH pages.",
    "Two NASA reports (NTRS 19840000109 and 19860055169) could not be downloaded in this run and are not used.",
    "The NASA abstract used for the first use is an OCR scan with letter-spaced text, so its wording is paraphrased.",
    "Wikipedia prints a second autoignition value cited to another source. It is not recorded."
  ],
  "story": {
    "why": "Methanol is a light alcohol that boils at 337.8 K at normal pressure, so it works as a two-phase heat transfer fluid in the moderate temperature band where heat pipes are used. A heat pipe carries heat by evaporating a liquid at the hot end and condensing the vapour at the cool end. NASA heat pipe reports list methanol with ammonia and Freon-21 as a candidate working fluid for aluminium and stainless steel envelopes. Its fire and toxicity hazards mean it has to be handled with care, and the material compatibility limits below apply to any design that uses it.",
    "uses": [
      {
        "where": "Gas-loaded variable-conductance heat pipe",
        "line": "A NASA report describes a methanol heat pipe that uses nitrogen gas to control temperature. The unit was built and tested with the heat source near ambient temperature."
      },
      {
        "where": "Dual-slot heat pipe radiators for solar dynamic power",
        "line": "A NASA study recommended stainless steel/methanol or titanium/methanol dual-slot heat pipe radiators as the baseline configuration for the CBC solar dynamic heat rejection system."
      },
      {
        "where": "Moderate-temperature heat pipes",
        "line": "A NASA manufacturing study limited its scope to aluminium and stainless steel heat pipes that used ammonia, Freon-21 or methanol as the working fluid."
      }
    ],
    "can_do": [
      {
        "label": "Phase change",
        "line": "Carries heat as a two-phase fluid. It boils at 337.8 K at normal pressure (NIST), and its enthalpy of vaporization is 37.6 kJ/mol at standard conditions (NIST).",
        "scope": "material"
      },
      {
        "label": "Liquid range",
        "line": "Stays liquid over a wide band. Its triple point is 175.5 K (NIST), and its melting point is 175.6 K in the Wikipedia infobox.",
        "scope": "material"
      },
      {
        "label": "Critical limit",
        "line": "Has a critical temperature of 513 K and a critical pressure of 81 bar (NIST). Designs should stay below these limits.",
        "scope": "material"
      },
      {
        "label": "Vapour pressure",
        "line": "Has a vapour pressure of 12.9 kPa at 20 °C (ICSC).",
        "scope": "material"
      },
      {
        "label": "Gas-loaded design",
        "line": "Can be used in a gas-loaded design that controls temperature with nitrogen gas, as one NASA report describes.",
        "scope": "material"
      }
    ],
    "compare": "Methanol is a volatile, flammable working fluid. Its boiling point, enthalpy of vaporization and flash point are the properties that set its heat transfer range and its fire risk. The NASA reports read here tested methanol alongside ammonia and Freon-21, but the passages read did not give numerical comparisons between those fluids, so no ranking is made here. The compare table lists the three properties that matter most for a heat pipe fluid.",
    "compare_rows": [
      {
        "label": "Boiling point",
        "benchmark": "boiling_point",
        "scope": "material"
      },
      {
        "label": "Enthalpy of vaporization",
        "benchmark": "enthalpy_of_vaporization",
        "scope": "material"
      },
      {
        "label": "Flash point",
        "benchmark": "flash_point",
        "scope": "material"
      }
    ],
    "handling": [
      "Methanol is toxic by several routes and flammable. Keep it in closed containers and away from strong oxidizers (NIOSH).",
      "Treat a leak as a fire risk, because the vapour forms explosive mixtures with air easily (ICSC).",
      "Do not charge methanol into aluminium envelopes. NASA reports the combination as incompatible and generating gas."
    ],
    "good_for": [
      "Heat pipes that must run at moderate temperatures without ammonia, where stainless steel or titanium walls are used (NASA).",
      "Gas-loaded variable-conductance designs for temperature control (NASA)."
    ],
    "watch_out": [
      "Flammable: the flash point is low and the vapour forms explosive mixtures with air easily.",
      "Toxic by ingestion, skin contact and inhalation, according to the PubChem ECHA data.",
      "Incompatible with aluminium envelopes, which generate gas (NASA)."
    ],
    "verdict": "Methanol is a workable heat pipe fluid in the moderate temperature band, but it is flammable and toxic, and aluminium walls are unsuitable.",
    "recipe": {
      "line": "Methanol (CH3OH) is made industrially by hydrogenating carbon monoxide: carbon monoxide and hydrogen (synthesis gas) react over a catalyst to produce methanol.",
      "parts": [
        {
          "name": "Carbon",
          "symbol": "C",
          "role": "The central carbon atom, bonded to the hydroxyl group and to the hydrogen atoms of the methyl group."
        },
        {
          "name": "Hydrogen",
          "symbol": "H",
          "role": "Three hydrogens sit on the carbon and one sits on the oxygen of the hydroxyl group."
        },
        {
          "name": "Oxygen",
          "symbol": "O",
          "role": "The hydroxyl oxygen, which together with one hydrogen makes the hydroxyl group that defines an alcohol."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "PubChem's ECHA data classify methanol as flammable and toxic by several routes. The NIOSH entry adds that it is a Class IB flammable liquid.",
        "points": [
          {
            "label": "The liquid",
            "line": "Methanol is a colourless liquid with a pungent odour. The ECHA aggregated set in PubChem lists it as highly flammable, toxic if swallowed, toxic in contact with skin, toxic if inhaled, and causing damage to organs."
          },
          {
            "label": "Exposure limits",
            "line": "NIOSH gives a time-weighted average limit of 200 ppm with skin absorption, and an immediately dangerous to life or health value of 6000 ppm."
          },
          {
            "label": "Vapour",
            "line": "ICSC says a harmful contamination of the air can be reached quickly on evaporation at ordinary room temperature, and that the vapour forms explosive mixtures with air easily."
          }
        ],
        "level": 0,
        "verdict": "Toxic and flammable: handle as hazardous"
      },
      {
        "title": "Near a leak or fire",
        "lead": "The flash point and the explosive limits set the risk: the vapour can ignite at low temperatures.",
        "points": [
          {
            "label": "Flash point",
            "line": "ICSC records a flash point of 9 °C by the closed-cup method. NIOSH records 52 °F, and Wikipedia gives 11 to 12 °C. The sources agree the flash point is low."
          },
          {
            "label": "Explosive limits",
            "line": "NIOSH gives a lower limit of 6.0% and an upper limit of 36%. ICSC gives a range of 6 to 50 vol% in air, so the upper value is not settled."
          },
          {
            "label": "Ignition",
            "line": "The autoignition temperature is 440 °C in ICSC and 470 °C in Wikipedia."
          }
        ],
        "verdict": "Flammable vapour near a leak or fire"
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Oxidizers",
            "line": "NIOSH lists strong oxidizers as incompatible with methanol."
          },
          {
            "label": "Leaks",
            "line": "Because explosive mixtures form easily, a leak should be treated as a fire risk, not only as a toxic release."
          }
        ]
      }
    ]
  },
  "updated": "2026-11-01",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 22,
    "unreachable": 0,
    "caveats": 2,
    "note": "Written by an AI assistant on 2026-11-01 from pages fetched in this run. Caveats: the NASA abstract is an OCR scan; the PubChem values come from the REST JSON endpoint."
  },
  "sources": {
    "nist-webbook-methanol": {
      "title": "NIST Chemistry WebBook: Methyl Alcohol, phase change data and thermodynamic data",
      "url": "https://webbook.nist.gov/cgi/cbook.cgi?Mask=4&ID=C67561",
      "year": 2026,
      "kind": "database",
      "license": "U.S. Secretary of Commerce, NIST Standard Reference Data (cited, not reproduced)"
    },
    "wikipedia-methanol": {
      "title": "Methanol (infobox properties, production and history)",
      "url": "https://en.wikipedia.org/wiki/Methanol",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA 4.0 (cited, not reproduced)"
    },
    "pubchem-methanol": {
      "title": "PubChem compound record: Methanol (CID 887), GHS Classification (ECHA aggregated set)",
      "id": "CID 887",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/887/JSON?heading=GHS+Classification",
      "year": 2026,
      "kind": "database",
      "license": "PubChem (NCBI), public domain; ECHA classifications attributed to ECHA"
    },
    "niosh-npg-methanol": {
      "title": "NIOSH Pocket Guide to Chemical Hazards: Methanol",
      "id": "NPG 0397; RTECS PC1400000",
      "url": "https://www.cdc.gov/niosh/npg/npgd0397.html",
      "year": 2026,
      "kind": "handbook",
      "license": "U.S. government work (cited, not reproduced)"
    },
    "icsc-0057": {
      "title": "ICSC 0057: Methanol (International Chemical Safety Card)",
      "id": "ICSC 0057",
      "url": "https://www.inchem.org/documents/icsc/icsc/eics0057.htm",
      "year": 2026,
      "kind": "handbook",
      "license": "ILO and WHO safety card (cited, not reproduced)"
    },
    "nasa-19750002275": {
      "title": "Heat pipe manufacturing study: aluminium and stainless steel heat pipes with ammonia, Freon-21 and methanol working fluids (NASA)",
      "id": "NTRS 19750002275",
      "url": "https://ntrs.nasa.gov/citations/19750002275",
      "year": 1975,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "nasa-19730022152": {
      "title": "Construction and testing of a gas-loaded, passive-control, variable-conductance heat pipe (NASA)",
      "id": "NTRS 19730022152",
      "url": "https://ntrs.nasa.gov/citations/19730022152",
      "year": 1973,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "nasa-19880013798": {
      "title": "Solar dynamic heat rejection technology, Task 2: heat pipe radiator development (NASA), Task 1 results",
      "id": "NTRS 19880013798",
      "url": "https://ntrs.nasa.gov/citations/19880013798",
      "year": 1988,
      "kind": "report",
      "license": "public domain (NASA)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/methanol-heat-pipe-fluid/"
}