alpha-Terpinene

Also known as: 1,3-Cyclohexadiene, 1-methyl-4-(1-methylethyl)-, 1-Isopropyl-4-methyl-1,3-cyclohexadiene, 1-Isopropyl-4-methylcyclohexa-1,3-diene, 1-Methyl-4-(propan-2-yl)cyclohexa-1,3-diene, 1-methyl-4-isopropyl-1,3-cyclohexadiene, 1-methyl-4-propan-2-yl-cyclohexa-1,3-diene, 1-methyl-4-propan-2-ylcyclohexa-1,3-diene, EINECS 202-795-1, FEMA No. 3558, L6U CUTJ AY1&1 D1, MFCD00001534, MFCD0001534, Terpilene, Terpinene, a-Terpinene, p-Mentha-1,3-diene, α -Terpinene, α-Terpinene, α-terpinene

alpha-Terpinene (CAS 99-86-5) is a compound in the Aliphatic Hydrocarbons category listed in the Jingsj chemical database. It has the molecular formula C10H16 and a molecular weight of 136.234 g/mol. Key properties include a melting point of -59.03°C (estimate), a boiling point of 174.1±0.0 °C at 760 mmHg, a density of 0.8±0.1 g/cm3 and a flash point of 46.1±0.0 °C. It is classified under GHS with signal word Warning and hazard statements H226 — Flammable liquid and vapour, H302 — Harmful if swallowed and H315 — Causes skin irritation. No supplier offers are currently listed; request a quote. Record last updated Aug 21, 2026.

CAS No.: 99-86-5
Jingsj CID: J-12418-6
Molecular Formula: C₁₀H₁₆
Molecular Weight: 136.234 g/mol
Category: Aliphatic Hydrocarbons
Last updated: 8/21/2026

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Physicochemical Properties

Melting Point	-59.03°C (estimate)
Boiling Point	174.1±0.0 °C at 760 mmHg
Density	0.8±0.1 g/cm3
Flash Point	46.1±0.0 °C
Exact Mass	136.125198
LogP	4.53
Appearance	Liquid \| Clear colorless to light yellow
Vapor Pressure	1.6±0.1 mmHg at 25°C
Refractive Index	1.476
Additional Property	95% ethanol: soluble1ml/2ml, clear, colorless \| Soluble in ether, alcohol, and ethanol (100 mg/ml). Insoluble in water.

GHS Safety & Compliance

Flammable / Irritant / Environmental HazardSignal word: Warning

H226 — Flammable liquid and vapour
H302 — Harmful if swallowed
H315 — Causes skin irritation
H319 — Causes serious eye irritation
H335 — May cause respiratory irritation
H411 — Toxic to aquatic life with long lasting effects
H413

Activity & Biological Data

Target	Trypanosoma evansi[1]
Additional Information	[1]. Matheus D Baldissera, et al. In Vitro and in Vivo Action of terpinen-4-ol, γ-Terpinene, and α-Terpinene Against Trypanosoma Evansi. Exp Parasitol. 2016 Mar;162:43-8. [2]. Patricia R Quiroga, et al. Contribution of Organic Acids to α-Terpinene Antioxidant Activity. Food Chem. 2019 Mar 30;277:267-272. [3]. Johanna Rudbäck, et al. α-Terpinene, an Antioxidant in Tea Tree Oil, Autoxidizes Rapidly to Skin Allergens on Air Exposure. Chem Res Toxicol. 2012 Mar 19;25(3):713-21. [4]. B Oliva, et al. Antimycotic Activity of Melaleuca Alternifolia Essential Oil and Its Major Components. Lett Appl Microbiol. 2003;37(2):185-7.

Target

Trypanosoma evansi[1]

Additional Information

[1]. Matheus D Baldissera, et al. In Vitro and in Vivo Action of terpinen-4-ol, γ-Terpinene, and α-Terpinene Against Trypanosoma Evansi. Exp Parasitol. 2016 Mar;162:43-8. [2]. Patricia R Quiroga, et al. Contribution of Organic Acids to α-Terpinene Antioxidant Activity. Food Chem. 2019 Mar 30;277:267-272. [3]. Johanna Rudbäck, et al. α-Terpinene, an Antioxidant in Tea Tree Oil, Autoxidizes Rapidly to Skin Allergens on Air Exposure. Chem Res Toxicol. 2012 Mar 19;25(3):713-21. [4]. B Oliva, et al. Antimycotic Activity of Melaleuca Alternifolia Essential Oil and Its Major Components. Lett Appl Microbiol. 2003;37(2):185-7.

Customs & Trade Information

HS Code	2902199090
Summary	2902199090 other cyclanes, cyclenes and cyclotherpenes。Supervision conditions:None。VAT:17.0%。Tax rebate rate:9.0%。MFN tariff:2.0%。General tariff:30.0%

Frequently Asked Questions

What is the CAS number of alpha-Terpinene?

The CAS number of alpha-Terpinene is 99-86-5.

What are the molecular formula and molecular weight of alpha-Terpinene?

alpha-Terpinene has molecular formula C10H16 and molecular weight 136.234 g/mol.

Is alpha-Terpinene hazardous?

alpha-Terpinene has GHS signal word Warning and hazard statements H226 — Flammable liquid and vapour; H302 — Harmful if swallowed; H315 — Causes skin irritation.

What are the upstream and downstream products of alpha-Terpinene?

For alpha-Terpinene, Upstream Products: Beta-pinene, Terpin monohydrate, limonene; Downstream Products: p-cymene, 4-Isopropylbenzoic acid, 4-Isopropylbenzyl alcohol.

Data compiled from public chemical databases such as PubChem and supplier catalogs; supplier offers are provided by suppliers.

Last updated: 8/21/2026

How to cite: Jingsj. "alpha-Terpinene (CAS 99-86-5)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-12418-6 (accessed 2026-11-06).

Data for reference only; verify product details with suppliers before purchase.