Thermal Extraction Devices

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    Cannabidiol (CBD)

    Identity

    Property Value
    Preferred name Cannabidiol (CBD)
    IUPAC name 2-[(1R,6R)-3-methyl-6-(1-methylethenyl)-2-cyclohexen-1-yl]-5-pentylbenzene-1,3-diol
    CAS number 13956-29-1
    PubChem CID 644019
    InChIKey QHMBSVQNZZTUGM-… (connectivity hash; stereoisomer suffix differs across NIST and PubChem records — confirm before machine use) [^1]
    Molecular formula C21H30O2
    Molecular mass 314.46 g/mol (exact 314.2246 Da)
    Compound class Phytocannabinoid; terpenophenolic meroterpenoid
    Stereochemistry Natural plant-derived CBD is (−)-trans-CBD (1R,6R). Synthetic material may be racemic or contain the (+)-enantiomer; cis/trans and enantiomer forms are distinct identities [^1]
    Major synonyms Cannabidiol, (−)-trans-cannabidiol, CBD; Epidiolex is the FDA-approved pharmaceutical formulation

    Identity notes

    • CBD vs. CBDA: GC with hot injectors decarboxylates CBDA to CBD, inflating apparent CBD values; LC methods distinguish the acid and neutral forms [^3].
    • CBD vs. THC isomers: At GC injector temperatures ≥250 °C, CBD can thermally cyclize to Δ9-THC and Δ8-THC; split injection at ≈200 °C is recommended to avoid artifactual THC [^2][^3].

    Physical properties

    Property Value Conditions / Notes
    Melting point ≈66 °C (also reported 62–63 °C for the α-form) Pure compound; polymorph-dependent [^1]
    Boiling point Predicted normal boiling temperature ≈422 °C (695.1 K) at 1 atm; extrapolated from vapor-pressure data, not an observed phase change Direct vapor-pressure measurements covered ≈61–121 °C; thermal decomposition prevents a direct atmospheric boiling observation [^4][^5]
    Vapor pressure Measured ≈10⁻³–10⁻¹ Pa over 61–121 °C (PLOT-cryo headspace); ambient values are model predictions First experimental CBD vapor-pressure data; uncertainty ≈13.5 % [^4]
    Water solubility <1 µg/mL (practically insoluble) pH-dependent; phenolic pKa ≈9.1
    logP (octanol-water) ≈6.3 (experimental) Highly lipophilic
    Thermal decomposition In GC-injector tests spanning 250–350 °C, partial CBD loss and formation of Δ9-THC, CBN, and Δ8-THC were observed; no universal onset is assigned Injector temperature, residence time, atmosphere, and sample preparation are study conditions [^2][^3]
    Oxidation behavior CBD oxidation under air/light is condition-dependent; no universal stability threshold is assigned CBN and related products were reported under cited study conditions [^3]

    | Known degradation products | Δ9-THC, Δ8-THC, and CBN were observed under cited GC-injector/thermal-treatment conditions [^2][^3]; CBE and HU-331 remain unverified here |

    Boiling point is not a device setpoint. The commonly repeated 160–180 °C figure is a device-setting or matrix-evaporation range, not a thermodynamic boiling point. The predicted normal boiling temperature of pure CBD is ≈422 °C at 1 atm and is not a direct phase-change measurement; device behavior must be established from vapor-pressure data and per-device testing [^4][^5].

    Thermal-extraction context

    CBD volatilizes from botanical matrix through vapor-pressure-driven evaporation, not bulk boiling. The extent of release and degradation is load-, airflow-, residence-time-, and device-dependent; no universal recovery fraction is assigned here [^3]. Device chamber temperature is not sample temperature; conduction/convection lag can put the sample below setpoint. The thermodynamic boiling point of the pure compound is not a device setpoint or a sample temperature.

    Cannabis occurrence

    Measured values are attached to batches and reports, not to cultivar names as universal claims:

    • High-CBD hemp flower cultivars have reported combined CBDA plus CBD in the ≈10–20% w/w range in published analyses (representative, batch-attached; e.g., Stack et al. 2023 characterized 32 high-CBD cultivars) [^6].
    • Measured drug-type (THC-dominant) flower batches in legal-market COA datasets report <1% CBDA plus CBD, often 0.1–0.5% [^7].
    • CBD is the neutral decarboxylation product of CBDA; fresh flower carries predominantly the acid form [^8].

    Biosynthesis and processing

    CBD is biosynthesized as CBDA via CBGA (cannabigerolic acid) through CBDAS (CBDA synthase), then decarboxylates to CBD under temperature- and time-dependent processing conditions; no universal device setpoint is assigned [^8]. The CBDAS/THCAS allele balance determines the CBD:THCA chemotype ratio; Type III (hemp) chemotypes are CBD-dominant [^9].

    Reported biological activity

    Human clinical evidence

    Randomized controlled trials of purified pharmaceutical CBD (Epidiolex) report reduced seizure frequency in Dravet syndrome [^10], Lennox-Gastaut syndrome [^11], and tuberous sclerosis complex [^12] at 10–50 mg/kg/day oral. These results apply to purified pharmaceutical CBD, not to inhaled whole-plant material, and are not generalizable to cannabis use. An acute randomized study of oral CBD also reported reduced anxiety during simulated public speaking in treatment-naïve social-phobia patients [^13].

    Human observational evidence

    Some observational studies of cannabis users report an association between higher CBD:THC ratios and lower self-reported anxiety/paranoia; this is correlational, not causal.

    Preclinical animal and in vitro evidence

    In vitro studies report CBD modulation of TRPV1, 5-HT1A, CB1 (negative allosteric modulation), and inhibition of CYP3A4/2C19/2C9 at micromolar concentrations (peer-reviewed review: Ibeas Bih et al. 2015 1). Human plasma concentrations after typical oral or inhaled doses are typically nanomolar-to-sub-micromolar per published PK reviews 2 — far below the 1–30 µM used in most mechanistic assays — so direct translation to cannabis-inhalation effects is not supported. In vitro aerosol studies report inflammatory responses to CBD-containing aerosols; human inhalation data are lacking.

    Industry and traditional claims

    “Full-spectrum is more effective (entourage effect)” and “CBD is non-psychoactive” are marketing simplifications with insufficient controlled evidence; the stomach-acid CBD→THC conversion claim is not demonstrated in humans.

    Degradation products

    • Thermal products observed under the cited GC-injector/thermal-treatment conditions: Δ9-THC, Δ8-THC, and CBN 34
    • Oxidative/photolytic: CBN under cited conditions 4; CBE and HU-331 remain unresolved in this record

    Sources

    1. Ibeas Bih C, Chen T, Nunn AVW, Bazelot M, Dallas M, Whalley BJ. Molecular targets of cannabidiol in neurological disorders. Neurotherapeutics. 2015;12(4):699–730. doi:10.1007/s13311-015-0377-3. PMID 26264914. (Peer-reviewed review of CBD’s molecular targets.) ↩

    2. Millar SA, Stone NL, Yates AS, O’Sullivan SE. A systematic review on the pharmacokinetics of cannabidiol in humans. Front Pharmacol. 2018;9:1365. doi:10.3389/fphar.2018.01365. PMID 30534073. ↩

    3. Tsujikawa K, Okada Y, Segawa H, Yamamuro T, Kuwayama K, Kanamori T, Iwata YT. Thermal decomposition of CBD to Δ9-THC during GC-MS analysis: a potential cause of Δ9-THC misidentification. Forensic Sci Int. 2022;337:111366. doi:10.1016/j.forsciint.2022.111366. PMID 35728413. ↩

    4. García-Valverde MT, Sánchez-Carnerero Callado C, Díaz-Liñán MC, et al. Effect of temperature in the degradation of cannabinoids: from a brief residence in the gas chromatography inlet port to a longer period in thermal treatments. Front Chem. 2022;10:1038729. doi:10.3389/fchem.2022.1038729. ↩ ↩2

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    Laboratory reports measuring this compound (1)

    Products with measurements (1)

    Related (6)

    Pages that link here (8)