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Title:	Synthesis and analysis of biolubricant based on dicarboxylate esters
Authors:	Waled Abdo Ahmed Abdulrab (P57916)
Supervisor:	Jumat Salimon, Prof. Dr.
Keywords:	Biolubricant Dicarboxylate esters Lubricating base oils Dissertations, Academic -- Malaysia
Issue Date:	4-Aug-2016
Description:	A synthesis of dicarboxylate esters for biolubricant base oil was carried out through esterification between dicarboxylic acids (succinic glutaric, adipic, pimelic, suberic, azelaic, sebacic, and dodecanedioic) with different types of alcohol: a) linear alcohols (1-butanol, 1-hexanol, 1-octanol, 1-decanol, and oleyl alcohol); b) secondary alcohols (2-butanol, 2-hexanol, 2-octanol, 3-octanol, 4-octanol, and 2-decanol); c) branched alcohol (2-methyl-1-butanol, 3-methyl-1-pentanol, 2-ethyl-1-butanol, 2-ethyl-1-hexanol, and 2-butyl-1-octanol,) in the presence of sulphuric acid as catalyst. The synthesized dicarboxylate esters showed high yield percentages in the range of 75 – 98 %. Confirmation of the chemical structures was done using FTIR and NMR (1H and 13C) spectroscopies. The FTIR spectra of dicarboxylate ester products clearly showed the peaks of C=O and C–O of ester group at 1732–1745 cm-1 and at 1166–1251 cm-1, respectively. The peak of the unsaturated aliphatic carbon atoms (C=C) appeared at 3003–3010 cm-1. 1H NMR analyses confirmed the proton chemical shifts of ester group at 3.83–4.04 ppm, tertiary carbons (-CH, 3°) at 2.12–2.15 ppm and unsaturated aliphatic carbons (HC=CH) at 5.31–5.35 ppm. The 13C NMR analyses confirmed the carbon chemical shifts of ester signals at 172.4–174.1 ppm, tertiary carbons (–C–, 3°) at 34.39–40.33 ppm and (C=C) at 129–130 ppm with different intensities. GC-MS analysis of D2EHD, D2EBD and D2MBD showed that the molecular masses were 454.6 m/z, 398.4 m/z and 370.5 m/z which were relatively close to the theoretical molecular weight of 454.73, 398.62 and 370.57 g/mole, respectively. The results for lubrication properties have shown that the branched dicarboxylate esters have very good low-temperature properties with pour points in the range of -8 °C to less than -70 °C. In general, dioleate of the short-chain dicarboxylic acids (C4–C7) showed low pour points compared to dioleate of medium-chain dicarboxylic acids (C8–C12). Dioleyl succinate (DOlSuc), dioleyl glutarate (DOlG), dioleyl adipate (DOlA), and dioleyl pimelate (DOlP) have pour points of −20 °C, −16 °C, −12 °C and −10 °C. Dioleyl suberate (DOlSub), dioleyl azelate (DOlAz), dioleyl sebacate (DOlS), and dioleyl dodecanedioate (DOlD) have shown high pour points of 7 °C, 10 °C, 15 °C and 20 °C, respectively. Furthermore, the flash point of the esters increased with their molecular weight. DOlD (731.23 g/mole) has the highest flash point of 305 °C, while di-2-butyl dodecanedioate (D2BD, 342.5 g/mole) has the lowest flash point of 140 °C. The oxidative stability and viscosity indices increased with the molecular weight and carbon chain-length of the esters, but decreased for unsaturated and branched chain carbons. Tribological results have indicated that the tested dicarboxylate esters have boundary lubrication properties with low friction coefficient (μ) of (0.1–0.29 μ) at 40 °C and (0.15–0.33 μ) at 100 °C, of those have been classified as Newtonian fluids. In general, the presence of two ester groups in the structure of dicarboxylic acid-based diester provides a positive impact on the lubrication and tribological properties. Overall, the results indicated that the branched dicarboxylate esters can be used as lubricating base oils without any additives, while the linear dicarboxylate esters can be used as lubricating base oils with pour point depressants.,Certification of Master's/Doctoral Thesis" is not available
Pages:	273
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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