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Q-Flex QDI Quinone Diimine Antidegradant—Improved Mixing Chemistry Resulting in a Better Balance of Productivity and Performance
Published in Anil K. Bhowmick, Current Topics in ELASTOMERS RESEARCH, 2008
Frederick Ignatz-Hoover, Byron To
In the presence of oxygen, the radical chain ends react with molecular oxygen forming polymeric peroxy-radicals, which terminate by hydrogen abstraction forming polymeric hydroperoxides. Oxidatively catalyzed shear-induced cleavage becomes “autoxidative” at high temperatures, leading to the rapid reductions in viscosity observed in high-temperature mixing. Thus, newly formed polymeric hydroperoxides decompose generating alkoxy- and hydroxyl-radicals. These radicals react with molecular oxygen to form additional polymeric hydroperoxides which in turn decompose to continue the cycle, i.e., the definition of “autoxidation”.
Accelerated oxidation of fresh and stored biodiesel samples obtained from castor and soybean oils using the petrooxy method
Published in Biofuels, 2021
Yguatyara L. Machado, Mariana C. Aragão, F. Murilo T. Luna, M. Alexsandra S. Rios, Célio L. Cavalcante
Biodiesel derived from vegetable oils (e.g. soybean, rapeseed, cotton, castor and others) is influenced by certain types with concentration of fatty acids in its composition. Some studies report that stored biodiesel is most likely to oxidize, compared to the stored mineral diesel, unless the biodiesel composition is altered by external agents, like additives, which have the purpose of retarding the oxidation process [13,14]. Storing biodiesel for long periods may also cause engines clogging, leading to operational problems, besides reducing the engine life-cycle [6]. The reaction rates in autoxidation schemes are dependent on hydrocarbon structures, heteroatom concentration, speciation, oxygen concentration and temperature [15–17].