Butylated hydroxy benzylidene ring: An important moiety for antioxidant synergism of semicarbazones
Document Type
Article
Publication Date
12-1-2021
Abstract
The compounds having two or more antioxidant functions in their structure exhibit antioxidant synergism that generally increase the antioxidant activity of these compounds. In this study, two series of semicarbazone (7a-jand7a `-j `) bearing butylated ortho and para hydroxy benzylidene ring were prepared for the investigation of antioxidant synergism. This study found that intramolecular hydrogen bond can form in semicarbazones due to the inappropriate position of hydroxyl group on benzylidene ring, which adversely affects the antioxidant synergism. As consequence, butylated para hydroxyl benzylidene phenyl semicarbazone (7a) (IC50 12.27 mu M) showed similar to 4.3 times and similar to 2.7 times better antioxidant activity than compounds7a `(IC50 53.30 mu M) and BHT (IC50 32.63 mu M), respectively, in DPPH assay. In addition, based on the solubility in trimethylolpropane trioleate (TMPTO) as synthetic base oil and obtained IC(50)results, oxidation stability of synthesized compounds was also evaluated by two kinds of differential scanning calorimeter (DSC) test, namely temperature ramping DSC and programmed temperature DSC. Thermogravimetric analysis is also performed for the thermal stability assessment. TMPTO incorporated with 0.25 mass% of 7c and7e were found better oxidative (around 2 times) and thermal resistance than BHT. This DSC results showed another important aspect of semicarbazones that proper modification of semicarbazones can be used in the synthetic lubricant oil as a potential antioxidant. Thus, the results of this study are promising which can be taken under consideration to design and prepare more efficient multipotent semicarbazones. GRAPHICS] .
Keywords
Antioxidant synergism, DSC, Lubricant oil, Oxidative stability, TGA, Semicarbazones
Divisions
nanocat
Funders
Universiti Malaya (RU2018),Ministry of Education, Malaysia (GC001C-14AET) (PG208-2015B)
Publication Title
Journal of Thermal Analysis and Calorimetry
Volume
146
Issue
5
Publisher
Springer
Publisher Location
VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS