Esters from castor oil functionalized with aromatic amines as a potential lubricant |
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| Authors: | Laura de Andrade Souza Denise Ramos Moreira Nágila Maria Pontes Silva Ricardo Martin Edmund Maier Paulo Roberto Campos Flexa Ribeiro Filho Francisco Murilo Tavares Luna Cesar Liberato Petzhold |
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| Affiliation: | 1. Chemistry Institute, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil;2. Laboratory of Polymers and Materials Innovation, Department of Organic and Inorganic Chemistry, Sciences Center, Federal University of Ceará, Fortaleza, CE, Brazil;3. Institut für Organische Chemie, Universität Tübingen, Tübingen, Germany;4. Lubricants Research Center, Department of Chemical Engineering, Technology Center, Pici Campus, Federal University of Ceará, Fortaleza, CE, Brazil |
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| Abstract: | Vegetable oils are very promising alternatives to fossil lubricants due to their abundance, low cost, excellent performance, and environmental friendliness. Due to its multifunctional structure, castor oil is an excellent precursor in the synthesis of new biolubricants. However, it showed poor thermal-oxidative stability and a higher pour point. This study used castor oil fatty acids prepared by transesterification (EHRO), epoxidation (TEPO), and oxirane ring opening with the aromatic amines aniline (ANIL) and p-anisidine (ANIS). The chemical structure of these oils was verified by 1H and 13C NMR analysis, and mass spectrometry. Measurements show that the presence of an aromatic amine increases the viscosity resulting in 172 (ANIL) and 199 (ANIS) cSt at 40°C, but reduces viscosity index to 16 and 1, respectively. In addition, the amine groups can scavenge radicals increasing their thermal and oxidative stability. These products do not oxidize copper, and tribological analysis reveals that ANIS has the lowest torque with wear equivalent to commercial mineral lubricant NH-140. |
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| Keywords: | aromatic amines bio-based lubricant castor oil epoxide opening tribological properties |
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