Schärer & Schläpfer AG is investing in a new Serepon plant. What does it expect from this, what does it mean for the customers, and what is Serepon, also known as Turkey Red Oil? In loose succession, we want to explore these and other questions. In part four, we present the new plant and explain what happens inside.

Sulfonated castor oil, better known as Turkey Red Oil, is still produced in large quantities in Rothrist, Aargau, and sold under the brand name Serepon. As the production plant is aging, it is now being replaced by a new, state-of-the-art facility. In the future, 1st pressing castor oil will be sulfonated in this plant, i.e. stirred together with concentrated, anhydrous sulfuric acid. Depending on the parameters, a variety of reactions and products are possible – including Turkey Red Oil.

Production method

"The chemistry and manufacturing process of sulfonated castor oil still work the same as ever," explains Roland Borner, Head of Development at Schärer & Schläpfer AG. "But each new generation of plant offers advantages." In the beginning – the company produced Serepon way back in the founding year 1947 – heating and cooling was still done by hand: The chemical workers used control valves to ensure that the temperature was "just right".

Compared to those days, the plant currently in operation is indeed modern. But the two simple, stainless steel monoreactors with volumes of 1500 and 3000 liters are around 30 years old. "They're done," Borner says. "The plant has been used a lot and has reached its natural end." Therefore, the plant has now been replaced by two new enamel multi-purpose reactors with volumes of 3200 and 5000 liters, in which, among other things, castor oil will also be sulfonated.

"The plant is 'state of the art', especially in terms of control and technology. Everything will be easier for employees because the processes are more highly automated than before."

This also benefits the customers. This is because correct, precise temperature control is one of the decisive factors for the quality of the product. The quality of the reactants, especially castor oil, is also important. Schärer & Schläpfer AG uses exclusively 1st pressing oil.

Speaking of quality

The sulfonated fatty acids are considered the most effective components of Turkey Red Oil; their content is used to distinguish the individual qualities. 50, 70 and 100% Turkey Red Oil are standard. Other concentrations are available on request.

Good to know

As it comes out of the boiler, Turkey Red Oil is "100% commercial". This corresponds to a mixture of 80% Turkey Red Oil and 20% water. 50% commercial Turkey Red Oil thus contains 40% pure Turkey Red Oil etc. This is not a peculiarity of Schärer & Schläpfer AG, but applies in general. "It's very special," Borner says. "You don't see that with any other product."

You can learn more exciting facts about Turkish red oil in the previous blog posts. For more detailed information and if you are interested in buying, please contact: