The real difference between TOFA and DTO is the rosin acid ceiling. TOFA 185 carries max 2% and TOFA 180 max 3% rosin acid; DTO Industrial carries max 40%, DTO Mid-High and Premium max 30%. TOFA gives lighter colour and higher acid value; DTO is chosen where rosin acid is wanted, in asphalt, adhesives and economical alkyds.
Same distillation train, two cut points
Distilled tall oil (DTO) and tall oil fatty acids (TOFA) are two products taken at different depths in the distillation of crude tall oil. DTO is a distillate in which fatty acids dominate but rosin acids are deliberately left in; TOFA is the same stream purified far further from rosin acids. The two families are listed under different CAS numbers: DTO grades 8002-26-4, TOFA grades 61790-12-3.
So "TOFA or DTO" is not a purity question. The right question is whether your formulation treats rosin acid as an impurity or uses it as a functional component.
The one decisive row: the rosin acid ceiling
The identically named row in both specifications (rosin acid content, ASTM D1240) is written an order of magnitude apart. On the TOFA side the ceilings are max 2% (TOFA 185) and max 3% (TOFA 180); on the DTO side max 40% (Industrial Grade), max 30% (Mid-High Grade) and max 30% (Premium). Even the most rosin-tolerant TOFA grade and the least rosin-tolerant DTO grade are separated by a wide gap.
Within the DTO family, the separation is made on unsaponifiable matter and appearance alongside the rosin ceiling: Industrial Grade at max 7% unsaponifiables and max 1.0% moisture, amber to dark amber; Mid-High Grade at max 7% unsaponifiables and trace moisture, amber; Premium tightening unsaponifiables to max 6% and specified as light amber, clear and bright.
TOFA and DTO grade specification table
What acid value and saponification value tell you
Acid value measures free carboxyl content and tells you how many reactive attachment points you have for esterification. TOFA grades carry the highest acid values at min 185 and min 180; on the DTO side Premium and Mid-High are min 170 and Industrial min 165. The gap looks small but it enters the calculation directly when you balance fatty acid against polyol in an alkyd recipe.
The difference in specification logic also shows in which row is absent. DTO grades are sold on saponification value (min 170-175, ASTM D94) but carry no iodine value row; TOFA grades are sold on iodine value (min 150, ASTM D5768) but carry no saponification value row. DTO is defined through total esterifiable matter, TOFA through unsaturation and therefore drying potential.
Alkyd colour: what rosin acid changes
Rosin acids behave differently from fatty acids at esterification temperature and influence both the initial colour of the finished resin and its tendency to yellow over time. That is why colour-sensitive alkyds, clear varnishes and white/pastel systems move the choice towards TOFA 185 with its max 2% ceiling. On the DTO side the most controlled colour profile is the Premium grade: light amber, clear and bright appearance, max 6% unsaponifiable matter and trace moisture, with premium alkyd resin and high-gloss varnish listed as its primary applications.
BİO BAZLI ÜRÜNLERTall Oil Fatty Acids 185 (TOFA)Rosin acid max 2%, unsaponifiables max 4%, iodine value min 150: for colour-sensitive alkyds, inks and dimer acid.BİO BAZLI ÜRÜNLERDistilled Tall Oil (DTO) PremiumLight amber, clear and bright DTO grade; acid value min 170, saponification value min 175, unsaponifiables max 6%.Why DTO is chosen on purpose
Rosin acid is not a burden in every formulation. In some systems it is exactly what is wanted: it contributes adhesion, hardness, tack and binding power. DTO grades are therefore bought as a composition choice, not as under-refined material. The product data lists their primary applications as follows:
- DTO Industrial Grade: asphalt and bitumen modification, flotation chemical production, adhesive and binder formulations, fuel additives, industrial lubricants and greases.
- DTO Mid-High Grade: alkyd resin and paint binder, coatings and varnish, esterification reactions and plasticiser synthesis, metalworking and cutting fluids.
- DTO Premium: premium alkyd resin, high-gloss varnish, high-performance adhesives and fillers, esterification for lubricant esters.
- In addition, DTO Industrial Grade is the only DTO grade specified on the iodine colour scale, at max 80 (ASTM D1348).
Which grade should you ask for?
The decision closes on three questions. First: is rosin acid functional in the formulation or unwanted? Functional means DTO, unwanted means TOFA. Second: how critical is colour in the finished product? Critical means TOFA 185 or DTO Premium; flexible means TOFA 180 or DTO Industrial. Third: are you building the recipe on acid value (min 180-185 in TOFA) or on saponification value (min 170-175 in DTO)? Those three answers point directly at which of the five grades to sample.
Validate with a sample and CoA
The rosin acid ceiling is a maximum; only the certificate of analysis for a given lot shows where that lot actually sits. If you are evaluating a move between TOFA and DTO, the fastest route is to request a sample and CoA of the candidate grade and validate it in your own esterification or saponification process. KORKİMYA supplies all tall oil grades in ISO tank containers and handles sample requests from the product pages.
Safe handling
What is the basic difference between TOFA and DTO?
Rosin acid content. TOFA grades carry max 2% (185) and max 3% (180) rosin acid; DTO grades carry max 30% (Premium and Mid-High) and max 40% (Industrial). Both come from the same distillation chain, taken at different cut points.
Can DTO be used in alkyd resin?
Yes. Alkyd resin and paint binder production is listed among the primary applications of both DTO Mid-High Grade and DTO Premium. For colour-sensitive, clear or white systems, TOFA 185 with max 2% rosin acid is preferred.
Why is the acid value of DTO grades lower than TOFA?
Because DTO holds a higher share of rosin acids and unsaponifiable matter, its free fatty acid share is relatively lower: DTO Industrial min 165, DTO Mid-High and Premium min 170, against TOFA 180 at min 180 and TOFA 185 at min 185.
What separates DTO Premium from Mid-High?
Both have a rosin acid ceiling of max 30%, acid value min 170 and saponification value min 175. Premium tightens unsaponifiable matter to max 6% (Mid-High max 7%) and is specified as light amber, clear and bright.
Why is there no saponification value in the TOFA specification?
The two families are defined on different axes. TOFA grades are sold on iodine value (min 150, ASTM D5768), which expresses unsaturation; DTO grades are sold on saponification value (min 170-175, ASTM D94), which expresses total esterifiable matter.