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Isostearic Acids
Published in Brajendra K. Sharma, Girma Biresaw, Environmentally Friendly and Biobased Lubricants, 2016
Helen Ngo, Robert O. Dunn, Winnie C. Yee
There are hundreds of biobased lubricants derived from vegetable oils in the market [1–3], with leading examples of hydraulic fluids from Mobil Corporation (Environmental Awareness Lubricants line) and metalworking additives from Lubrizol Corporation (Lubrizol® 5411) [4]. Although vegetable oils provide a source of environmentally desirable lubricants, they are not widely utilized because of their poor oxidative stability [5–9]. Saturated branched-chain fatty acids, including isostearic acids, have a hydrophilic carboxylic acid headgroup and a lipophilic alkyl chain with a methyl branching group located at various positions along the chain (Scheme 4.1) [10]. Isostearic acids and their simple alkyl esters have the advantages over common fatty acids in that they have much better oxidative stability than unsaturated fatty acids and typically have lower melting points (MPs) and cloud points (CPs) than comparable saturated linear chain fatty acids [11]. As a result, branched fatty acids are ideal in many applications including body washes [12,13], coatings [14], cosmetics [12,13], lubricant additives [15–18], hydraulic fluids [19–21], and emulsifiers [22].
Sources and major biogeochemical pathways of organic matter in the mangrove system of Rufiji estuary
Published in Chemistry and Ecology, 2019
Odd carbon-numbered and branched-chain fatty acids are normally synthesised by bacteria and have been used as bacterial biomarkers [11,43–45]. Bacterial biomarkers in this study ranged between 1.17 (station 3) and 9.46% (station 1) of total fatty acids. Fatty acids C15:0 were recognised at all the three stations while C15:1 fatty acid was existent only at stations 2 and 3. At stations 1 and 3, C17:0 fatty acid was characterised while C17:1 was found only at station 3. The n-fatty acids of < C12 in sediments are seldom reported, but were existent at stations 1 and 3. The presence of C8 to C10 fatty acids imply that they are derived mainly from bacteria due to abundant bacteria on surface or shallow sediments [33,46,47].