Tall oil fatty acid (TOFA, CAS 61790-12-3) is not a single product — it is a family of grades defined mainly by acid value and rosin content. Buyers who specify “TOFA” without a grade often end up with the wrong product for their application. This guide explains the key specifications, what they mean, and how to choose the right TOFA grade.
1. What Is TOFA?
Tall oil fatty acid is a by-product of the kraft (sulfate) pulping of pine wood. During pulping, the resinous components of the wood form crude tall oil (CTO), which is refined by fractional distillation. The fatty acid fraction — TOFA — consists mainly of unsaturated C18 fatty acids: oleic, linoleic and smaller amounts of linolenic and other acids. Because it is derived from renewable pine biomass, TOFA is a bio-based alternative to petroleum-derived and palm-derived fatty acids.
2. The Two Key Specifications
2.1 Acid value
Acid value (mg KOH/g) measures the free fatty acid content. TOFA grades are commonly offered at acid values around 188, 190 and 192. Higher acid value means higher fatty acid content and fewer neutral (ester) impurities — generally preferred for reaction chemistry such as alkyd resin production.
2.2 Rosin content
Rosin (resin acids) is the main impurity in TOFA. Grades are defined by maximum rosin content, typically 2%, 5% or 9%. Lower rosin means a purer, lighter fatty acid with better color and reactivity — and a higher price. Rosin affects color, odor, reactivity and downstream product quality, so the grade must match the application.
3. TOFA Grades at a Glance
| Grade | Acid value (typ.) | Rosin (max) | Typical uses |
|---|---|---|---|
| Low-rosin TOFA | 192 | 2% | Alkyd resins, high-quality coatings, esters, lubricant additives |
| Mid-rosin TOFA | 190 | 5% | General coatings, soaps, metalworking fluids |
| High-rosin TOFA | 188 | 9% | Cheaper applications: some soaps, asphalt emulsifiers, fuel additives |
Note: exact values vary by producer; always confirm the COA against your requirement.
4. Other Properties to Check
- Saponification value — related to acid value; useful for soap and ester production calculations.
- Iodine value — indicates the degree of unsaturation; affects drying behavior in coatings and oxidation stability in lubricants.
- Color (Gardner) — matters for light-colored coatings and cosmetics-adjacent applications.
- Water content — should be low; moisture affects esterification and storage stability.
5. How to Choose the Right Grade
- Check your downstream chemistry: alkyd and ester producers usually want low-rosin, high-acid-value TOFA for reactivity and color.
- Balance cost vs quality: high-rosin grades are cheaper but darker and less reactive — fine for soaps and asphalt emulsifiers, not for premium coatings.
- Verify by COA: always request the measured acid value, rosin content and color on the certificate of analysis.
- Test before scaling: run a small batch of your product with the candidate grade to confirm performance.
6. FAQ
What is the difference between TOFA and tall oil?
Crude tall oil (CTO) is the raw by-product of kraft pulping; tall oil is a broad term. TOFA is the distilled fatty acid fraction of tall oil, much purer and higher in fatty acid content.
Is TOFA the same as oleic acid?
No. TOFA is a mixture of unsaturated C18 acids (mainly oleic and linoleic) plus small amounts of rosin; oleic acid is a single purified fatty acid.
Why does rosin content matter?
Rosin acids are bulky, colored and slower to react. High rosin gives darker products, slower esterification and can cause haze in coatings — hence lower-rosin grades command a premium.
Is TOFA renewable?
Yes. TOFA comes from pine biomass, a renewable feedstock, making it a low-carbon bio-based alternative to petroleum-derived fatty acids.
PolyblueChem supplies tall oil fatty acid (TOFA, CAS 61790-12-3) in the 192/190/188 acid-value grades with rosin limits of 2%/5%/9%, with COA and MSDS. See our TOFA introduction for the full background. Contact us for specifications and quotations.