SINTESIS SENYAWA OMEGA-6 TERKONJUGASI ASAM 8,10,12-OKTADEKATRIENOAT DARI MINYAK JARAK; SYNTHESIS OF CONJUGATED OMEGA-6 8,10,12- OCTADECATRIENOIC ACID FROM CASTOR OIL

Bayu Refindra Fitriadi, Hardjono Sastrohamidjojo

2011 | Disertasi | PROGRAM STUDI S2 KIMIA JURUSAN KIMIA

Synthesis of conjugated omega-6 compounds 8,10,12-octadecatrienoic acid from castor oil has been done. 8,10,12-octadecatrienoic acid was synthesized through several steps of reaction, i.e. (1) isolation of methyl ricinoleate from castor oil by transesterification in the presence of potassium hydroxide, (2) hydrolysis of methyl ricinoleate with potassium hydroxide, (3) oxidation to double bond of ricinoleic acid using dilute potassium permanganate in alkaline condition at 0-5°C, and (4) dehydration of hydroxyl group of trihydroxy stearic acid using P2O5 at 140°C for 3.5 hours. Structural characterization was done by means of IR, 1H-NMR, UV-Vis dan GC-MS spectrometers. Transesterification of castor oil using KOH produced methyl ricinoleate as main component in 77% yield. Hydrolysis of methyl ricinoleate produced ricinoleic acid in total yield of 74%. Oxydation of ricinoleic acid produced 9,10,12-trihydroxy stearic acid (THSA) in total yield of 75% which were found as two diastereoisomers i.e., ? dan ?. ? product was produced as white crystal with melting point of 106°C, while ? product was obtained as white powder with melting point of 125°C. Dehydration reaction to 9,10,12-trihydroxy stearic acid produced conjugated omega-6 compounds 8,10,12-octadecatrienoic acid which was produced as brownish liquid, in 81% yield. Carboxylic group of 9,10,12- trihydroxy stearic acid was not affected by dehydration reaction.

Kata Kunci : omega-6 terkonjugasi, asam 8,10,12-oktadekatrienoat, reaksi dehidrasi