Terpineol is a secondary alcohol with the molecular formula C10H18O. It is produced commercially by the acid-catalysed hydration of alpha-pinene, or by fractional distillation of pine oil at high purity. The product that leaves a terpineol plant is not a single pure compound but a mixture of isomers: alpha-terpineol (the dominant one), beta-terpineol, gamma-terpineol, and terpinen-4-ol. The grade system, PG (Perfumery Grade), EP (Extra Pure or Extra Purified), and Alpha, refers to how high the alpha-terpineol isomer content is and how rigorously the other isomers and impurities have been separated out. Each grade has a characteristic odour, physical appearance, and field of use.
Terpineol PG (Perfumery Grade)
PG is the entry-level grade, typically containing 85-90% total terpineol with alpha-terpineol as the predominant component but with a meaningful proportion of other isomers and terpene hydrocarbons. It is a viscous, colourless to very pale yellow liquid with the characteristic sweet, floral, lilac-like odour of terpineol. Despite being the lower-purity grade, PG is widely used because its odour profile is full and rounded rather than flat:
- Phenyl cleaners, floor cleaners, and disinfectants where terpineol provides the characteristic pine-floral note and some antibacterial activity
- Soap and detergent fragrance, particularly in bar soaps and dishwashing liquids where a fresh, clean odour is needed at low cost
- Industrial and household insecticide formulations as a solubiliser and fragrance
- Low-cost fragrance bases for agarbatti (incense sticks) and dhoop
The PG grade is broadly comparable to pine oil at 85% terpineol content, and in some markets the two terms are used interchangeably, though pure terpineol grades will have lower hydrocarbon content than most pine oil products.
Terpineol EP (Extra Pure)
EP grade typically specifies 95% or higher total terpineol content, with tighter limits on colour (Gardner colour below 1 or water-white), specific gravity, and refractive index. The odour is cleaner and more consistently floral than PG. The uses are correspondingly more demanding:
- Mid-range fragrance formulations where a consistent, repeatable terpineol note is required batch after batch
- Terpinyl acetate production: EP grade is the preferred feedstock for esterification because impurities in PG-grade material can slow the reaction or cause side products (see terpinyl acetate)
- Technical cleaning and degreasing where residue or colour from terpene hydrocarbons is undesirable
- Flotation processing as a higher-purity frother where terpineol purity correlates with selectivity
Alpha-Terpineol (Alpha Grade)
Alpha-terpineol at 98% or higher purity is the most refined grade. At this level, the beta and gamma isomers are almost completely absent. The result is a product with a very clean, sharp floral odour that fragrance evaluators describe as lily-of-the-valley adjacent, often specified by name in fine fragrance formulas rather than as a generic terpineol. Applications include:
- Fine fragrance compounding where the exact odour character of alpha-terpineol, not blended terpineols, is specified
- Pharmaceutical use: alpha-terpineol has documented antimicrobial activity and appears in some pharmacopoeial references and topical formulations
- High-purity synthesis feedstock for production of other fragrance molecules
- Flavour applications in very small quantities (alpha-terpineol is listed as a flavour ingredient in certain regulatory frameworks)
Grade Comparison at a Glance
| Grade | Terpineol Content | Typical Colour | Key Uses |
|---|---|---|---|
| PG | 85-90% | Pale yellow to colourless | Phenyl, soaps, basic fragrances |
| EP | 95%+ | Water-white | Mid-range fragrance, terpinyl acetate, flotation |
| Alpha | 98%+ | Water-white | Fine fragrance, pharma, synthesis |
Storage and Handling
All terpineol grades are stable under normal storage conditions but should be kept in sealed containers away from light. Terpineol can oxidise slowly on prolonged air exposure, forming oxidation products that affect odour. For high-purity alpha grade, nitrogen blanketing during storage and transfer is recommended. Flash point is around 88-90 deg C, so it is not classified as highly flammable, but normal precautions for flammable liquids still apply.
Terpineol in all three grades is available from Shade Shine Pine Industries in 200 litre barrels and tanker quantities. We have supplied terpineol to fragrance houses, cleaning product producers, and specialty chemical buyers across India and internationally since 1980. Contact us on +91 96965 09933 or send an enquiry to info@shadeshinepine.com. Samples are available so you can confirm the grade meets your specification before ordering.
