Optimization of chemical synthesis of cis-9, trans11. octadecadienoic acid through KOH-catalyzed dehydration of castor oil by RSM
Conjugated linoleic acid is a collective term which refers to a mixture of positional and geo*"tric isomers of linoleic acid with coniugated double bonds thot have revealed a wide range of biotogical activities. Cis-9,trans-ll-Octadecadienoic acid (9c,1lbl8:2) is the most abundant isomer and is of interest because of its anticarcinogenic and anticholesterolemic properties. To further study the metabolic pathways and physiological effects of 9c, I I t- I 8 :2, it 'is iesirable to obtain substantial amounts of this compound in a relatively pure form, ideally by simple methods from readily accessible materials. The optimization of conditions for Cis-9, trans-il-Octadecadienoic acid production (the most biologically active CLA) by dehydration of costor oil as starting material, inwhich the mainfatty acid component is ricinoleic acid, was investigated using RSM. This optimization process was done by KOH as an inexpensive dehydiating reagent instead of DBU. The yield of Cis-9, trans-ll-Octadecadienoic acid was evaluated inder a variety of experimental conditions, including reaction temperature, time and amount of catalysr, each of them at three levels. It was found that the temperature of dehydration and amount of catalyst were important factors in CLA isomer composition and yfeid. When the reaction temperature was increased, the yield of 9c,l1t-18:2 decreased but with increasing catalyst amount, it was increased. Time had a slight impact on CLA production and with incriasing in time, CLA yield was fficted slightly. The temperature, 50 'C; catalyst amount, 1.8 g, ani reaction time, 5.25 h were found to be the optimum conditions to achieve the maximum yield of 9c,l1t-L8:2 (53.93%).