
Baynox® frequently asked questions and answers
Baynox® is the LANXESS brand name for phenolic antioxidants which are used for the stabilisation of fuels, especially biodiesel and blends thereof with petro diesel. Baynox® increases the shelf life of fuels and protects against engine damage.
Find here all answers to your questions.
Not only is biodiesel considerably better value for money than the mineral-based variant, it is also environmentally friendly and can be "home grown".
Biodiesel is produced chemically through transesterifcation of vegetable oils with methanol. Native vegetable oil is primarily rapeseed oil in Europe; used fats from the food industry and animal fats can also be used. The one thing all of these have in common is that the raw materials are renewable energy sources.
The consequences of oxidation are firstly that biodiesel decomposes to form short-chain fatty acids, and secondly that insoluble polymers (gums) are formed. If nothing is done to counteract this, it is possible that the engine may become damaged as a result.
The oxidation of oils and fats by atmospheric oxygen is known as rancidity. Rancid oils and fats are unusable.
Now the rapid radical destruction cycle begins. This peroxide radical immediately creates a new radical from the fatty acid methyl ester, which in turn binds with oxygen in the air. The destructive radical auto-oxidation cycle begins. During this process, up to 100 new radicals are created quickly from one single radical, meaning that decomposition occurs at an exponentially rapid rate, and the oil spoils and becomes rancid very quickly.
It is easy to identify rancid oils in the home from their typically unpleasant odor. The smell comes from the short-chain degradation products produced by the unsaturated fatty acids such as butyric acid.
A variety of different tocopherol isomers exist with differing effective strengths, but they all have the same basic chemical structure. A hindered aromatic phenol structure is bonded to a long-chain phythyl group. This is the actual active chemical structure of the antioxidant.
As animals and people are unable to produce vitamin E themselves, they have to take it in with their food, in order to protect their body fat against oxidation.
Nevertheless, it must be noted that vitamin E is gradually used up in this process.
This involves pumping the air through biodiesel which has been heated to a temperature of 110°C using a piece of equipment which meets the required standards. If short-chain fatty acids are present in the distillate as cleavage products of the fatty acid oxidation, this indicates that the biodiesel is unstable. The DIN EN 14214 standard stipulates that biodiesel must remain stable and undecomposed in the Rancimat for at least 6 hours.
Biodiesel has to fulfill this requirement not only at the production plant but at the pump when refueling vehicles.
To find out how quickly biodiesel ages after its production, a number of tests were carried out in our laboratories.
A fresh biodiesel (rapeseed methyl ester) from a recognized producer was aged in the laboratory. To do this, the biodiesel was agitated in an open 500 ml glass bottle at 40 °C in a temperature-controlled cupboard. Every few days a sample was taken and the stability was tested according to the Rancimat test.
The stability constantly decreases. After approximately 10 days it has fallen by one hour and is consequently outside of the limits permitted by the DIN EN 14214 standard. After two months the biodiesel is completely unstable and oxidation can take place unimpeded in a chain reaction, in other words it oxidizes quickly and is unusable.
During this laboratory test in a glass bottle other influences which may have accelerated the aging process of the biodiesel were ruled out. For example, heavy metals such as copper from equipment and fittings can speed up aging considerably.
When you consider that fuel in the tank of a car is very likely to reach temperatures of up to 40 °C and, more notably, that car drivers do not always completely empty the tank within 10 days, it is obvious that to ensure the operational safety of biodiesel it is essential that it has sufficient stability when it leaves the plant, and, where possible, that this is even above the standard.
This means it is essential for the stability of biodiesel that the level of oxidation protection is just as high as that produced by the naturally occurring vitamin E.
This process can be clearly seen if a bottle filled with biodiesel is left standing for a long time. As soon as the antioxidant has been used up and the induction time is over, the oxygen is used and negative pressure builds up.
This effect can be seen on a plastic bottle in the way it becomes deformed.
Increasing amounts of Baynox® were added to biodiesel (RME) which had a stability of 8.2 hours in the Rancimat. The increase in the stability is in relation to the quantity of Baynox®.
With approximately 1,000 ppm Baynox® it is possible to reach a value of approximately 10 hours in the Rancimat. This gives the biodiesel sufficient protection for transportation and a long period of storage at the gas station and in the tank of a diesel-fuelled vehicle.
Experience shows that a different dose is recommended for biodiesel made from old cooking fat and oils and animal fats and oils than for biodiesel made from rapeseed oil or other types of vegetable oil.
Our research center conducts tests with increasing amounts of Baynox® and can show you by means of a diagram exactly which improvements are produced by adding which quantities of Baynox®.
With this as a basis, you will always know exactly how much stabilizer you require for what use and thereby avoid unnecessary costs caused by adding too much and/or not adhering to the standard.
Additionally, LANXESS offers a broad range of analytical testing methods and expert know-how that can also be requested for other chemically related questions concerning biodiesel.
Please contact us if you have any chemical or technical queries.
Apart from the active ingredient and biodiesel (RME), Baynox® does not contain any alcohol or mineral-based solubility promoters or other auxiliary agents. The active ingredient combusts in the vehicle's engine without leaving any residue. This is checked with every single batch.
Baynox® is not a hazardous substance and has the same water hazard class as Biodiesel. Baynox® is non-toxic and does not pose a risk in wastewater.
In one of our tests on a used fat biodiesel, there was definite clouding after approximately 4-6 weeks' storage with a large surface area. This precipitation (gum) consisted of polymer biodiesel. With 500 ppm Baynox® no precipitation occurred.
Adding Baynox® stops the formation of oligomer or polymer components in biodiesel.
Baynox® is available in several different types of container, depending on customer requirements:
- 1,000 l IBC: 20 % active ingredient dissolved in biodiesel (RME compliant with DIN EN 14214)
- 10-18,000 l tanker or container: 20 % active ingredient dissolved in Biodiesel (RME compliant with DIN EN 14214) or in customer's own supplied biodiesel on request.
- A sample may be requested for test purposes