In emulsifier and surfactant production, tall oil fatty acid is an intermediate whose head group is changed: saponification gives an anionic soap, ethoxylation a non-ionic structure and amidation an amide derivative. The long hydrocarbon chain stays constant. TOFA Rich Distillate is listed in the product data with a surfactant production area.
Why is a fatty acid a surfactant intermediate?
A surface-active molecule is defined in two parts: a head group compatible with water and a tail compatible with oil. A molecule carrying both accumulates at the interface where the two phases meet, and stays there. Lowering surface tension, foaming, lifting soil and building an emulsion are all consequences of that single property.
A long-chain fatty acid brings the tail half of that structure ready-made. There is no need to synthesise, extend or branch the chain; the raw material is already a predominantly C18 mixture. What the producer and the formulator work on is the head group. That is exactly the role of a fatty acid in surfactant production: a ready source of hydrophobic chain carrying a head group to be modified.
The fit of tall oil fatty acid to that role is visible in the product data. The production areas of TOFA Rich Distillate include surfactant production and industrial chemical synthesis, while the application lists of TOFA 180 and TOFA 185 carry industrial soap and cleaning products.
BİO BAZLI ÜRÜNLERTall Oil Fatty Acids Rich DistillateTOFA Rich Distillate is listed in the product data with surfactant production and industrial chemical synthesis production areas, and ships in IBCs and ISO tank containers. Sample and quote available on request.Changing the head group: soap, ethoxylate, amide
The carboxyl group of a fatty acid is a door onto different surfactant classes. Which door you go through determines the charge of the molecule you obtain, its solubility in water, and how it behaves against hard water and pH.
- Saponification: the carboxyl group is neutralised with an alkali or an amine; the result is an anionic soap. It is the shortest and most common route, and the behaviour of the product depends heavily on the counter-ion.
- Ethoxylation: ethylene oxide units are added to the carboxyl group; the result is a non-ionic structure carrying no ionic charge. Water solubility is tuned by the number of units added.
- Amidation: the carboxyl group forms an amide bond with an amine, giving a non-ionic, covalently bound head group. That intermediate is also the starting point for further derivatives.
- Esterification: reacting with an alcohol gives structures that dissolve in oil and work in systems that do not mix with water.
All four routes start from the same measurable value: free acid content. It is reported in the specification as the acid value and stoichiometry is calculated from it. That is min 185 for TOFA 185 and min 180 for TOFA 180 (ASTM D1980). For TOFA Rich Distillate the product data gives a typical acid number of 178.5.
How does counter-ion selection change the emulsion?
On the soap route the fatty acid itself stays constant, while the type of base used in the neutralisation changes the character of the product markedly. Sodium based soaps give harder, less water-soluble structures, while potassium based soaps give softer, more readily soluble products. Amine based neutralisation produces a water-dispersible component that also contributes alkalinity.
That choice feeds straight into the type of emulsion. Which phase the emulsifier dissolves in more strongly is the primary factor deciding whether the emulsion is oil-in-water or water-in-oil. An emulsifier with better water solubility supports a water-continuous system; one with better oil solubility supports an oil-continuous system.
In practice a formulator rarely uses a single emulsifier; two components with different water and oil solubility are used together to build a more tightly packed film at the interface. Fatty acid derivatives usually form the anionic or non-ionic leg of that pair.
Emulsion stability: what holds the interfacial film?
An emulsion is not a thermodynamically stable system; droplets tend to coalesce and phases tend to separate. The job of the emulsifier is to slow that separation, and it does so through three mechanisms.
- It lowers interfacial tension, making it easier to create new droplet surface and reducing droplet size.
- It builds a mechanical film at the interface; when droplets collide, that film acts as a barrier against coalescence.
- In an anionic structure it gives the droplet surface a charge; droplets of like charge repel each other and find it harder to approach.
The third mechanism is both the strength and the weak point of the soap route. Electrostatic repulsion is an effective source of stability, but it weakens as the ionic load of the medium rises. That is why in systems with hard water, a high electrolyte load or a drop in pH, a purely anionic soap may not be sufficient on its own and is used together with a non-ionic structure.
Two values on the raw material side stand out for stability. Unsaponifiables are the fraction that does not take part in neutralisation and contributes nothing to the emulsion: max 6% in TOFA 180 and max 4% in TOFA 185 (ASTM D1065), with a typical value of 5.2% in TOFA Rich Distillate. Rosin acid content influences the character and colour of the soap: max 3% in TOFA 180 and max 2% in TOFA 185 (ASTM D1240), with a typical total rosin acid figure of 20.4 in Rich Distillate.
Two applications outside the scope of this article
Two major applications of fatty acid soaps have their own articles on this site and are not repeated here. The first is industrial soap and cleaning product manufacture: the saponification reaction itself, its role in metal cutting fluids and the structure of the formulation are the subject of a separate article. The second is road and bitumen emulsions: the emulsifier role in bitumen emulsions, asphalt modification and adhesion behaviour are covered in another article.
The scope of this article is the general intermediate chemistry underneath both: how the head group is chosen, what the counter-ion changes and what the interfacial film rests on. That is where you start when designing a new surfactant product.
Which tall oil input do you start from?
Three tall oil inputs come up in surfactant production. What separates them is how tight the specification is and whether the rosin acid fraction enters the product.
The reading is this: choose TOFA 185 where a tight specification and low rosin acid are required, and TOFA 180 where a wider tolerance is sufficient. Where the rosin acid fraction is meant to enter the product deliberately, evaluate Rich Distillate; its packaging flexibility also differs, because an IBC option is available.
Sample, validation and supply
No decision in surfactant development is taken from a raw material page. The right sequence is to run your own derivative synthesis with a sample, evaluate the structure you obtain with your own emulsion tests, and only then move to a supply agreement.
- CAS number: 61790-12-3 (TOFA grades).
- Packaging: ISO tank container 20-24 MT net for TOFA 180, 20-22 MT net for TOFA 185, IBC and ISO tank container for Rich Distillate.
- Storage: 20-40°C, closed tank or container, away from direct sunlight.
- Shelf life (TOFA grades): 12 months, extendable to 24 months with quality control testing.
- KKDIK registered; Turkish Safety Data Sheet (SDS/GBF) and a CoA for every lot.
Why is a fatty acid used as a surfactant intermediate?
Because it brings the tail half of a surface-active molecule ready-made. There is no need to synthesise the long hydrocarbon chain; the producer works only on the head group. Saponification, ethoxylation, amidation and esterification are four ways of obtaining different surfactant classes from the same chain.
What does counter-ion selection change?
Sodium based soaps give harder, less water-soluble structures and potassium based soaps softer, more readily soluble ones, while amine based neutralisation produces a water-dispersible component that also contributes alkalinity. Which phase the emulsifier dissolves in more strongly decides whether the emulsion is oil-in-water or water-in-oil.
Why might an anionic soap not be enough on its own?
Part of the stability contribution of an anionic soap comes from like-charged droplets repelling each other, and that repulsion weakens as the ionic load of the medium rises. In systems with hard water, a high electrolyte load or a drop in pH, the anionic structure is usually used together with a non-ionic component.
When is TOFA Rich Distillate preferred?
When the rosin acid fraction is meant to enter the product deliberately. The product data gives a typical total rosin acid of 20.4, an acid number of 178.5 and a saponification value of 184, and its production areas include surfactant production. Packaging flexibility also differs, since an IBC option exists.
How do I get a sample and a quote?
State your target surfactant class (soap, ethoxylate, amide or ester), the emulsion type and your estimated annual volume in the inquiry form on the product page. KORKİMYA provides a free sample for laboratory validation and a per-lot CoA.