Mariusz Władysław MALKO, Agnieszka WRÓBLEWSKA* – Institute of Organic Chemical Technology, West Pomeranian University of Technology, Szczecin, Poland
Please cite as: CHEMIK 2016, 70, 4, 193–202
Limonene oxidation processes are one of the key methods for its management. Limonene extracted from the orange peels is a valuable raw material for the obtaining of valuable derivatives, for example: perillyl alcohol, which inhibits the growth the cancer of colon and breast.
Limonene is a monoterpene compound which has many applications in the chemical industry. It is the main component of essential oils obtained from waste citrus peels (biomass). It can be obtained by the natural and synthetic methods, for example with help of pyrolytic processes. Natural methods (simply distillation or steam distillation citrus peels) allow to recycle the waste citrus peels derived from the food industry and obtain almost pure limonene with a small amount of toxic waste. Pyrolytic methods require high temperatures and generate significant quantities of waste water, moreover this methods are very harmful to the environment. Limonene undergoes very easily oxidation processes. It allow to obtain very valuable oxygenated derivatives of limonene, for example perillyl alcohol. Limonene oxidation process can be carried out using different oxidizing agents such as hydrogen peroxide (30 wt% or 60 wt% water solutions) or t-butyl hydroperoxide (TBHP, 5-6 M solution in decane). Also the utilization the selected microorganisms can cause the formation of oxygenated derivatives of limonene but in these processes the multicomponent mixtures of oxygenated derivatives of this compound are obtained. The methods which used hydrogen peroxide or TBHP as oxidizing agents allow to obtain high yields of the appropriate oxygenated derivatives of limonene at a high conversion of limonene. Now, at the Institute of Organic Chemical Technology, West Pomeranian University of Technology in Szczecin are performed studies on the modern, “green” technology which allows to obtain oxygenated derivatives of limonene by oxidation of limonene with 60 wt% hydrogen peroxide, in various solvents and in the presence of mesoporous titanium silicate materials, such as: Ti-MCM-41 and Ti-SBA-15. In this method, the only by-product connected with the transformation of hydrogen peroxide is water, and other organic by-products can be easily developed. Limonene oxidation processes are carried out at mild conditions (temperatures up to 120°C and atmospheric pressure).
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