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http://dx.doi.org/10.14478/ace.2014.1015

Insulation Properties and Evaluation of Diglycerol Ester Synthesized by Solid Acid Catalysts  

Gwon, Miseong (Korea Institute of Industrial Technology(KITECH))
Baek, Jae Ho (Korea Institute of Industrial Technology(KITECH))
Kim, Myung Hwan (Korea Institute of Industrial Technology(KITECH))
Park, Dae-Won (Pusan National University)
Lee, Man Sig (Korea Institute of Industrial Technology(KITECH))
Publication Information
Applied Chemistry for Engineering / v.25, no.3, 2014 , pp. 254-261 More about this Journal
Abstract
The transformer is a static electrical device that transfers energy by inductive coupling. Then, heat is occurred at coils, inner transformer was filled with insulating oils for cooling and insulation. Although mineral oil as insulating oil has been widely used, it does not meet health and current environmental laws because it is not biodegradable. Therefore, in this study, the diglycerol ester was synthesized with diglycerol and fatty acids (oleic acid and caprylic acid) over various catalysts for insulating oil having biodegradability, high flash points and low pour points. The sulfated zirconia ($SO_4{^{2-}}/ZrO_2$) catalyst prepared at different calcination temperature shows the highest conversion of fatty acids at $600^{\circ}C$ due to crystallinity and high density of acid sites per surface area. When the molar ratio of oleic acid and caprylic acid is 1:3, the diglycerol ester shows superior insulation properties that are the flash point of $306^{\circ}C$ and pour point of $-50^{\circ}C$. The insulation properties of synthesized diglycerol ester shows the pour point of $-50^{\circ}C$ and the flash point of over $300^{\circ}C$. Therefore, diglycerol ester is superior to the vegetable oils in insulation properties.
Keywords
diglycerol ester; fatty acid; insulating oil; esterification; solid acid catalysts;
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