SENG SOI HOONG1*; MOHD ZAN ARNIZA1; NEK MAT DIN NIK SITI MARIAM1; ABU HASSAN NOOR ARMYLISAS1; SOOK WAH TANG1; TUAN ISMAIL TUAN NOOR MAZNEE1 and SHOOT KIAN YEONG1
Received: 30 March 2022 Accepted: 29 August 2022 Published Online: 3 October 2022
Palm-based used cooking oil (UCO) is an inexpensive material that could be used as a bio-lubricant. However, its use as a bio-lubricant is limited by its inferior cold flow and oxidation stability properties. This study shows an approach to make bio-lubricant base oil from UCO that displayed good cold flow and oxidation stability. UCO was saponified and hydrolysed to yield a mixture of fatty acids, which was subsequently reacted with hydrogen peroxide and acetic acid to generate an estolide mixture with hydroxyl and carboxylic acid groups. The hydroxyl groups of the estolide mixture were end-capped with lauric acid, while its carboxylic acid groups were converted to either ester or amide functionality with 2-ethylhexanol and dibutylamine, respectively. Physicochemical properties evaluation revealed that the saturated branched structure of estolide ester and amide contributed to improved pour point (-12oC) and better oxidation stability up to 200oC as compared to UCO. Additionally, the estolide ester and amide exhibited a better viscosity index and pour point than a commercial mineral oil lubricant. The estolide ester can be classified as ISO VG 68 base oil, while the estolide amide displayed a higher viscosity grade (ISO VG 150) due to the presence of dibutylamide moiety.KEYWORDS:
1 Malaysian Palm Oil Board,
6 Persiaran Institusi, Bandar Baru Bangi,
43000 Kajang, Selangor, Malaysia.
* Corresponding author e-mail: email@example.com