Tall oil fatty acids and rosin (resin) acids are two different molecule families out of the same crude tall oil distillation. Fatty acids are straight-chain C18 carboxylic acids; rosin acids are cyclic diterpene acids of the abietic and pimaric type. The fatty acid fraction gives flexibility and drying, the rosin acid fraction gives hardness and tack.

One feedstock stream, two molecule families

Softwood crude tall oil (CTO) is described in the product data explicitly as a mixture of "resin acids, fatty acids and neutral matter". Distillation separates those three groups: the fatty acid fraction is drawn off as TOFA, the resin acid fraction as rosin, and the residue as pitch. TOFA and rosin are therefore not two quality levels of each other; they are two chemically distinct products from one source.

That split is the main fork in our tall oil value chain guide as well: CTO is a single by-product, and the product family drawn from it divides into a fatty acid branch and a rosin acid branch that go to entirely different industries.

BİO BAZLI ÜRÜNLERSoftwood Crude Tall Oil (CTO)A complex mixture of resin acids, fatty acids and neutral matter; the primary distillation feedstock for TOFA, rosin and pitch. Resin acids are reported by TUR-T 14 and acid number by TUR-T 11.

What kind of molecule is a rosin acid?

Fatty acids are straight-chain molecules with a single carboxyl group: oleic, linoleic, linolenic and stearic acid belong to that family. Rosin acids have a cyclic diterpene structure and are read in two sub-types: abietic-type (abietic, neoabietic, palustric, dehydroabietic, dihydroabietic) and pimaric-type (pimaric, isopimaric, sandaracopimaric). Both families carry a carboxyl group, so both can esterify and saponify, but the backbone is completely different.

The formulation difference follows from that. A straight chain brings freedom of movement and unsaturation into the film; a cyclic backbone brings hardness, glassy character and tack. Same reactive group, two entirely different mechanical outcomes.

Measured composition: the two fractions side by side

Tall Oil Fatty Acids Rich Distillate is the one grade in the range that reports component by component how the two families sit together. On the fatty acid side the measured values are: linoleic and its isomers 32.8% + 7.3%, oleic 7.5% and oleic isomers 7.3%, linolenic 6.2%, palmitic 3.8%, stearic 1.3%, arachidic 0.8%, behenic 0.7%, lignoceric 0.2%. Fatty acids up to C18 total 65.6 and fatty acids above C18 total 1.9.

On the rosin acid side, the same analysis reports abietic 6.7%, palustric 3.4%, dehydroabietic 2.7%, pimaric 1.9%, isopimaric 1.7%, neoabietic 1.1%, sandaracopimaric 0.4% and dihydroabietic 0.2%; total resin acids are given as 20.4. The product's acid number is 178.5, saponification number 184 and unsaponifiable matter 5.2%.

BİO BAZLI ÜRÜNLERTall Oil Fatty Acids Rich DistillateThe grade with a component-level fatty acid and resin acid breakdown; for alkyd resin, adhesive, surfactant and metalworking fluid formulations.

Fatty acid fraction vs rosin acid fraction

CriterionFatty acid fraction (TOFA)Rosin acid fraction (rosin)
Molecular backboneStraight-chain C18 carboxylic acidsCyclic diterpene acids
Main componentsLinoleic, oleic, linolenic, palmitic, stearicAbietic, palustric, dehydroabietic, pimaric, isopimaric
Total measured in Rich Distillate65.6 up to C18 (1.9 above C18)20.4
Unsaturation specificationIodine value min 150 in TOFA gradesNo separate iodine value in the specification
Share in the supplied streamDominant fraction in TOFA gradesMax 2% in TOFA 185, max 3% in TOFA 180, max 40% in DTO Industrial
Character contributed to the filmFlexibility, oxidative drying, ester chainHardness, tack, adhesion
Typical destination applicationsAlkyd resin, dimer acid, soap, flotation, metalworkingAdhesives and binders, printing ink binders, asphalt modification

Tack or flexibility: which side of the recipe are you growing?

Raising the rosin acid share in a formulation hardens the film and adds tack; raising the fatty acid share brings flexibility and drying behaviour forward. In the tall oil range that balance is set directly by grade selection. The lowest rosin share is in TOFA 185 (max 2%); the highest is in DTO Industrial Grade (max 40%). In between sit TOFA 180 (max 3%), DTO Mid-High and DTO Premium (both max 30%).

Adhesives and inks, or alkyds and soaps?

The application lists confirm the split. DTO Industrial Grade, with the high rosin share, lists adhesive and binder formulations together with asphalt and bitumen modification among its primary uses; the adhesion and binding power rosin acid brings is exactly what is wanted there.

TOFA 185, with the low rosin share, lists alkyd resin and oil-modified polymer production, dimer acid and polyamide production, printing ink and pigment dispersion, and industrial soap as its primary uses. Printing ink appears on both sides but in different roles: the rosin acid side feeds binder hardness, the fatty acid side feeds pigment dispersion and film flexibility.

BİO BAZLI ÜRÜNLERDistilled Tall Oil (DTO) Industrial GradeAt max 40% rosin acid, the most rosin-rich distillate in the range; for adhesives, binders and asphalt modification.BİO BAZLI ÜRÜNLERTall Oil Fatty Acids 185 (TOFA)At max 2% rosin acid, the purest fatty acid grade in the range; for alkyd resin, dimer acid and inks.

What to ask when you buy

  • Is the rosin acid share a ceiling or a target band? In these specifications the row is written as a maximum (ASTM D1240).
  • What is the actual rosin acid value of the lot? Only the certificate of analysis for that lot shows it.
  • Do you need a component-level breakdown? The Rich Distillate grade reports abietic- and pimaric-type components individually.
  • Is rosin acid functional in the recipe? If it is, a distillate with a higher rosin share is a better starting point than a low-ceiling TOFA grade.

Safe handling

Tall oil derivatives are fatty-acid and resin-acid type liquids; they can irritate skin and eyes on contact and may generate vapour when heated. Distillates are stored at 20-40 °C in closed containers, while crude tall oil is held at 40-70 °C for pumpability. Use chemical-resistant gloves and eye protection and follow the current Safety Data Sheet (SDS) for the relevant product.
What is the chemical difference between rosin acid and fatty acid?

Fatty acids are straight-chain C18 carboxylic acids (linoleic, oleic, linolenic, palmitic, stearic). Rosin acids have a cyclic diterpene structure and split into abietic-type (abietic, palustric, dehydroabietic, neoabietic, dihydroabietic) and pimaric-type (pimaric, isopimaric, sandaracopimaric).

Why is rosin acid never driven to zero in TOFA?

Both fractions come from the same distillation stream and complete separation is not practical, so the specification states a ceiling instead: max 2% for TOFA 185 and max 3% for TOFA 180.

In which applications is rosin acid a wanted component?

Wherever adhesion, hardness and tack are needed. DTO Industrial Grade, at max 40% rosin acid, is listed for adhesive and binder formulations and for asphalt and bitumen modification.

Can I see the rosin acid distribution component by component?

Yes. The Tall Oil Fatty Acids Rich Distillate analysis reports abietic 6.7%, palustric 3.4%, dehydroabietic 2.7%, pimaric 1.9%, isopimaric 1.7%, neoabietic 1.1%, sandaracopimaric 0.4% and dihydroabietic 0.2% separately, with total resin acids given as 20.4.

Can rosin acids esterify too?

Yes, both families carry a carboxyl group, so both enter esterification and saponification reactions. The difference is not the reactive group but the backbone: the cyclic structure adds hardness and tack to the film, the straight chain adds flexibility and drying behaviour.