alpha-Terpineol Chemical Properties

Melting point:

31-35 °C (lit.)

Boiling point:

217-218 °C (lit.)

Density 

0.93 g/mL at 25 °C (lit.)

vapor pressure 

6.48Pa at 23℃

FEMA 

3045 | ALPHA-TERPINEOL

refractive index 

1.482-1.485

Flash point:

90 °C

storage temp. 

2-8°C

solubility 

0.71g/l

form 

Liquid After Melting

pka

15.09±0.29(Predicted)

color 

Clear colorless

Specific Gravity

0.9386

Odor

at 100.00 %. pine terpene lilac citrus woody floral

Odor Type

terpenic

Water Solubility 

negligible

Merck 

14,9171

JECFA Number

366

BRN 

2325137

Dielectric constant

2.8（20℃）

InChIKey

WUOACPNHFRMFPN-UHFFFAOYSA-N

LogP

2.6 at 30℃

CAS DataBase Reference

98-55-5(CAS DataBase Reference)

NIST Chemistry Reference

3-Cyclohexene-1-methanol, «alpha»,«alpha»4-trimethyl-(98-55-5)

EPA Substance Registry System

.alpha.-Terpineol (98-55-5)

Safety Information

Hazard Codes 

Xi

Risk Statements 

10-38-36/37/38

Safety Statements 

16-37-26-37/39

WGK Germany 

1

RTECS 

WZ6700000

TSCA 

Yes

HS Code 

29061400

Hazardous Substances Data

98-55-5(Hazardous Substances Data)

MSDS

• Language:English Provider:p-Menth-1-en-8-ol
• Language:English Provider:ACROS
• Language:English Provider:ALFA

alpha-Terpineol Usage And Synthesis

Description

(-)-alpha terpineol is the alpha form of terpineol, a naturally monoterpene alcohol that can be isolated from various kinds of sources such as cajuput oil, pine oil, and petitgrain oil. The alpha form is the major constituent of terpineol. It is a common component in perfumes, cosmetic and flavors. It is also a kind of solvent used for extracting natural spices and as a kind of solvent of acetate fibers. Moreover, it exhibited strong and broad antimicrobial activity against fungi, bacteria and virus. Study has demonstrated that is antibacterial (bactericidal) effect originated from its destroying effect on the cell wall and cell membrane of bacteria. It also has certain anticonvulsant activity.

References

de Sousa, Damiao Pergentino, Lucindo Quintans Jr, and Reinaldo Nóbrega de Almeida. "Evolution of the anticonvulsant activity of α-terpineol."Pharmaceutical Biology 45.1 (2007): 69-70.
Park, Soon-Nang, et al. "Antimicrobial effect of linalool and α- terpineol against periodontopathic and cariogenic bacteria." Anaerobe 18.3 (2012): 369-372.
Dabbah, Roger, V. M. Edwards, and W. A. Moats. "Antimicrobial action of some citrus fruit oils on selected food-borne bacteria." Applied microbiology19.1 (1970): 27-31.

Properties and Applications

α-Terpineol is a colorless, crystalline solid, smelling of lilac. The most important commercial grade of terpineol consists of a liquid mixture of isomers that contains mainly α-terpineol and a considerable amount of ?γ-terpineol. This mixture has a stronger lilac odor than does pure crystalline α-terpineol.
Hydrogenation of α-terpineol yields p-menthan-8-ol. Terpineol is readily dehydrated by acids, yielding a mixture of unsaturated cyclic terpene hydrocarbons. Under mildly acidic conditions, terpin hydrate is formed. The most important reaction for the fragrance industry is esterification, particularly acetylation to terpinyl acetate.
Terpineol with its typical lilac odor is one of the most frequently used fragrance substances. It is stable and inexpensive and is used in soaps and cosmetics.

Chemical Properties

α-Terpineol is a kind of clear colorless liquid after melting, which has a characteristic lilac odor with a sweet taste reminiscent of peach on dilution.

Occurrence

Reported found in more than 150 derivatives from leaves, herbs and flowers; the d-, l- and dl-isomers are known: the d-form is found in the essential oils from Cupressaceae in general; also in the oils of Elettaria cardamomum, star anise, marjoram, clary sage, neroli and others. The l-form is found in Satureia montana, lavandin, cajeput, lime, lemon, cinnamon leaves and the distillates from Pinaceae (with exception of Pinus silvestris, which contains d-terpineol together with racemic form); likewise, Nectandra elaiophora (wood) and petitgrain bigarade. The racemic form is found in cajenne linalool, Thymus caespititius, cajeput, Eucalyptus globulus; mixed with the l-form it is found in petitgrain; a nondefined form of terpineol has been reported in the bitter orange. Reported found in over 260 natural sources including apple, apple juice, apricot, sweet and sour cherry, citrus peel oils and juices, orange, lemon, etc.

Uses

A naturally-occuring monoterpene alcohol.Alpha-terpineol is used as an antioxidant, antiseptic, antihypernociception and anti-inflammatory. It is also used as a solvent. It is an important ingredient of pine oil disinfectants. Further, it is used as a fragrance in perfumes, fat denaturant for soap production and synthetic flavoring agent.

Definition

ChEBI: A terpineol that is propan-2-ol substituted by a 4-methylcyclohex-3-en-1-yl group at position 2.

Preparation

Although α-terpineol occurs in many essential oils, only small quantities are isolated, for example, by fractional distillation of pine oils.
A common industrial method of α-terpineol synthesis consists of the hydration of α-pinene or turpentine oil with aqueous mineral acids to give crystalline cis-terpin hydrate (mp 117 °C), followed by partial dehydration to α-terpineol. Suitable catalysts are weak acids or acid-activated silica gel.
Selective conversion of pinene, 3-carene, and limonene or dipentene to terpineol, without terpin hydrate formation is also used. Addition of organic acids (weak acids require catalytic amounts of mineral acids) produces terpinyl esters, which are subsequently hydrolyzed to terpineol, sometimes in situ.

Aroma threshold values

Detection: 280 to 350 ppb. Aroma characteristics in 1% ethanol: pine-like, woody and resinous with a slight cooling lemon and lime citrus nuance, and a floral dry out.

Taste threshold values

Taste characteristics at 2 to 25 ppm: woody, terpy, lemon and lemon–lime-like with a slight herbal and floral nuance. Taste characteristics at 10 to 25 ppm: citrus woody with a lemon and lime nuance. It has a slight soapy mouthfeel.

General Description

α-Terpineol is a monoterpene alcohol. It is one of the components responsible for the antifungal activity of Melaleuca alternifolia (tea tree) essential oil. The reaction rate constant of α-terpineol with OH radical and ozone was found to be (1.9±0.5)×10^-10cm³ molecule^-1s^-1 and (3.0±0.2)×10^-16cm³ molecule^-1s^-1, respectively.

Flammability and Explosibility

Non flammable

Synthesis

Obtained from terpin hydrate by splitting off water; from pentane tricarboxylic acid by cyclization, followed by esterification to the hydroxy ester, then the unsaturated ester and Grignard to terpineol; also from isoprene and methyl vinyl ketone, using methyl magnesium iodide.

alpha-Terpineol(98-55-5)Related Product Information

• Methylparaben
• Paraquat dichloride
• 2-Amino-2-methyl-1-propanol
• Isopropyl acetate
• Acetonitrile
• Methyl acrylate
• Cyclohexene
• ISOPROPYL LAURATE
• Diethylstilbestrol
• 2-Methyl-1-propanol
• 1-Propanol
• 2-Cyclohexen-1-one
• Basic Violet 1
• Methanol
• Isopropyl alcohol
• Oleyl alcohol
• Dihydro-alpha-terpineol
• Pinitol oil