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Keywords:

  • Cu catalysts;
  • Iodine value;
  • Oxidation stability;
  • Selective hydrogenation

Abstract

Selective hydrogenation over pre-reduced 8% Cu/SiO2 catalysts has been carried out on a series of non-food oils methylesters. The catalyst shows a very high diene:monoene selectivity, thus allowing one to reduce not only the linolenic component, but also the linoleic one in this way enriching the oil in oleic acid and avoiding a contemporary increase in stearic acid concentration. This treatment improves the oxidation stability of the oil while keeping acceptable viscosity and cold properties and can be used to standardize a wide variety of different available feedstock.

Practical applications: Vegetable oils from different sources can be used as primary, secondary (when they are residues of other processes), or tertiary (post-consumer wastes) feedstock for the chemical industry. Their composition can be very different as far as unsaturated components are concerned. This variability is an issue because it can lead to multiple products and moreover the unsaturation level, that is the iodine value, is strongly related to oxidation unstability. The process we propose here allows one to standardize the oil composition improving the oxidation stability and keeping acceptable fluidity. The very mild experimental conditions, 4–6 atm of H2 and 160–180°C, the use of a non-toxic and cheap metal, make this process sustainable and easily viable, e.g., in hardening plants.