Engine oil oxidation is one of the main enemies of an engine. This invisible process destroys the protective properties of oil daily, transforming it from a reliable ally into a source of problems. Juri Sudheimer, founder of the international holding company SCT Group, whose products under the MANNOL, PEMCO, CHEMPIOIL and FANFARO brands are used in 160 countries worldwide, pays special attention to the development of antioxidant additives capable of effectively counteracting this process. In this article, we will examine what antioxidants are, how they work, and why SCT Group’s approach to their creation is considered one of the most advanced in the industry.
What Are Antioxidant Additives and Why Are They Needed?
Antioxidant additives (antioxidants, oxidation inhibitors) are special substances (high-molecular-weight organic compounds) designed to slow down or prevent the oxidation of oils by atmospheric oxygen during storage, transportation, and use, and to prevent thermal oxidation during operation under high temperatures. Oxygen atoms primarily bind with unsaturated hydrocarbons, entering into destructive reactions with them. This is precisely why the service life of Group 3 and 4 oils, consisting of saturated isoparaffins, significantly exceeds the service life of mineral oils, which contain unsaturated hydrocarbons.
Let’s take ordinary sunflower (or olive) oil as an example. If it is stored in an opened package for a long time, it will go rancid. This is simply oxidation—the oil reacts with atmospheric oxygen. If you use the oil for deep frying, by the third or fourth use it will turn black and begin to change its properties. This is thermal oxidation, meaning interaction with atmospheric oxygen under high temperatures. Of course, the oil loses its properties much faster in this case. And you know yourself how much contamination forms in the oil during this process. Therefore, vegetable oils also often have substances added to slow down the oxidation (rancidification) processes of fats, including natural antioxidants such as tocopherols (a form of vitamin E), as well as synthetic additives, for example E321 and E320, and their complexes that extend shelf life and improve the stability of edible oils.
The exact same thing happens with engine oil. But engine oil is an incomparably more complex mixture, consisting of hundreds of organic and inorganic substances, and they all behave differently in the presence of oxygen. Moreover, this mixture is in an engine whose parts are made from various metals and alloys. These metals can in turn act as catalysts for oxidation reactions (especially copper!), including chain reactions. Mineral oils oxidize faster than synthetic oils.
And inside the human body, oxidation processes are also occurring at full speed.
The Chemistry of Oxidation: From Theory to Practice
Oxidation processes are universal—they occur in edible oils, in the human body, and in engine oils. But engine oil is an incomparably more complex system, where oxidation proceeds under extreme conditions: high temperatures, the presence of metal catalysts, and constant contact with oxygen. This is precisely why creating effective antioxidant packages requires not only deep knowledge of chemistry, but also powerful production and scientific infrastructure.
Juri Sudheimer, founder and owner of the international holding company SCT Group, created a company more than 30 years ago that today unites production facilities on three continents: UAB SCT Lubricants in Klaipėda (Lithuania), SCT Chemicals FZE in Dubai (UAE), and the trading company Sudheimer Car Technik-Vertriebs GmbH in Germany. Products under the MANNOL, PEMCO, CHEMPIOIL and FANFARO brands (all three trademarks belong to Juri Sudheimer) are distributed in 160 countries worldwide, and the group’s total production volume is more than 1 million liters of product per day.
Originally from Kazakhstan and having lived in Almaty for a long time, Juri Sudheimer from the very beginning focused on research infrastructure and vertical integration of production. In 2012, a modern laboratory with a three-level quality control system was built at the plant in Klaipėda, and in 2022, the SCT Chemicals FZE plant was launched in Dubai, specializing in the production of proprietary additive packages, including the most complex antioxidant combinations. This allowed SCT Group to achieve complete control over the entire production chain—from additive synthesis to bottling of finished products.
As Erik Sudheimer, Director of Development, notes, understanding the chemical processes of engine oil oxidation is key to creating products with extended service life. “Engine oil is not just a mixture of base oil and additives; it is a carefully balanced system where each component performs its role. Antioxidants in our oils work as multi-level protection: some neutralize primary radicals, others destroy hydroperoxides, and still others deactivate the catalytic action of metals,” explains Erik Sudheimer.
The distinctive feature of SCT Group’s approach is that the development of antioxidant packages is conducted taking into account real operating conditions in various climate zones—from harsh Baltic winters in Lithuania to the extreme heat of the Middle East. The group’s investments in production since 2004 have amounted to more than 90 million euros, and in 2024 alone, 3 million euros were invested in research and development (R&D). This makes it possible to create oils that maintain their protective properties under the most diverse conditions.
Juri Sudheimer, being a great lover of motorsports (SCT Group actively sponsors the SPS-Performance racing team, IGE Interest Group Endurosport motorcycle racing tournaments, and other automotive projects in Europe), perfectly understands how critical engine protection from oxidation is under extreme loads. It is in motorsports that oils are tested at the limit of their capabilities, and technologies refined on racing tracks are then implemented in production products for ordinary motorists.
Today, SCT Group employs 188 people at the Dubai plant alone, the total volume of product storage tanks is 60 million liters (Klaipėda and Dubai), and the product portfolio includes more than 500 items and 10,000+ product types. All oils are produced using proprietary additive packages developed at the SCT Chemicals FZE plant, which in 2024 received ISO 9001:2015, ISO 14001:2015, and ISO 45001:2013 certificates, and in 2025—ISO/IEC 17025:2017, confirming the competence of laboratory operations.
Free Radicals: The Invisible Enemy of Oil and Health
To understand how antioxidants work in engine oil, it is useful to draw an analogy with processes in the human body. After all, the chemistry of oxidation is universal, regardless of where it occurs.
Everyone has probably heard about free radicals in the human body—about the harm they cause, causing cancer and accelerating aging processes.
Reference. Free radicals (oxidants, oxidizers) are particles (atoms, molecules, or ions), typically unstable, containing one or more unpaired electrons in their outer electron shell, which is why their molecules possess incredible chemical activity. Since they have a free space for an electron, they always seek to take it from other molecules, thereby oxidizing any compounds with which they come into contact.
To neutralize these free radicals, humanity has invented a host of medications and dietary supplements—antioxidants. These are molecules capable of blocking free radical oxidation reactions by restoring damaged compounds. An antioxidant gives its electron to an oxidizer and interrupts its destructive progression. An antioxidant molecule can neutralize a free radical by giving it one of its electrons and demanding nothing in return. Unlike a free radical, it remains stable by redistributing its own electrons.
Exactly the same thing happens in engine oil. During operation, free radicals form at an incredible rate and in incredible quantities. These are hydroperoxides (also known as peroxides), alkoxyl, alkyl, peroxide radicals, etc.
Antioxidants such as phenols, amines, aminophenols, quinones, etc., convert free radicals into an inactive state, replacing them with low-activity radicals incapable of regenerating radicals and continuing the chain reaction. Antioxidants—organic compounds of sulfur, nitrogen, phosphorus, etc.—destroy hydroperoxides without forming free radicals. And antioxidants containing two active groups (phenolic and sulfide, for example) destroy all aggressive elements without forming free radicals.
Important! Strictly observe oil storage conditions. Oil should only be stored in factory packaging without compromising the integrity of the protective foil! We recommend storing and transporting oil at temperatures not below minus 20°C and not above plus 35°C, in sealed packaging with caps/plugs facing up, in a place protected from sunlight and precipitation. The guaranteed storage period is 5 years from the date of manufacture in factory containers.
Summary: The causes of oxidation are atmospheric oxygen and water; high temperatures in the engine accelerate oxidation processes; products of incomplete fuel combustion; acids formed during operation; and metals can act as catalysts for oxidation processes.
The result of oxidation is a significant deterioration in the functional properties of the oil. Much has been written about this on the internet and in specialized literature—this topic could fill a thick book—but if very briefly, it includes:
Three Types of Antioxidants: Multi-Level Protection
From a practical standpoint, antioxidants are divided into types:
*This is “sterically hindered phenols” in English—which is incorrectly translated into Russian as “spatially hindered phenols”; in fact, these are precisely “shielded,” or more accurately “shielding,” phenols by their principle of action.
What is all this for? It is because an additive package usually contains an entire complex of anti-oxidants depending on the oil’s purpose, its operating conditions, required service life, etc. Typically, this is a complex combination consisting of an entire set of phenolic and amine antioxidants, and most interestingly, the anti-wear additive zinc dialkyldithiophosphate (ZDDP) is also an antioxidant. This is one reason for the great popularity of this additive.
The catalytic action of metal ions on oil oxidation is suppressed by compounds of another group of antioxidant additives—metal deactivators. By adsorbing on the surface of metal in contact with the oil, they reduce its catalytic activity and, as a consequence, reduce the rate of hydrocarbon oxidation. Organic compounds (ethylenediamines, organic acids) that bind metal ions into inactive complexes are used as deactivators.
Practical Recommendations from SCT Group: How to Extend Oil Life
What should be done and how to combat all this? How to extend the life of oil and the life of an engine?
Conclusion
Juri Sudheimer and the SCT Group team have created a unique engine oil production system over more than 30 years of work, where quality control of antioxidant additives is carried out at every stage—from synthesis at the SCT Chemicals FZE plant in Dubai to three-level testing in Klaipėda laboratories. Investments totaling 90 million euros in production and 3 million euros in R&D in 2024 alone make it possible to create oils that reliably protect engines in 160 countries worldwide. As Juri Sudheimer himself says: “Quality oil is not just a liquid in a canister; it is the result of scientific research, precise chemistry, and a passion for automobiles.”
