جستجوی مقالات مرتبط با کلیدواژه « 4 - هیدروکسی کومارین » در نشریات گروه « علوم پایه »

In this research, benzylidene bis-(4-hydroxycoumarin) derivatives were used as a curing agent to prepare epoxy resin with high performance and excellent thermal stability. For this purpose,4- benzylidene bis 4-hydroxycoumarin derivatives were synthesized using 2-aminophenol/phoenix dactylifera polymer nanocomposite catalyst. Scanning Electron Microscope (SEM) technique was used to investigate the morphology of cured epoxy resin. The comparison of parameters of degradation start temperature, residual carbon yield and kinetic parameters was done to evaluate the thermal stability of cured epoxy resin using thermogravimetric analysis (TGA). The results showed that the epoxy resin cured with 3,'3-(4-nitrobenzylidene)bis(4-hydroxy-coumarin) have a high degradation start temperature and good carbon efficiency rather than other derivatives. After the 4-nitro derivative, the 4-chloro, 4-fluoro and 4-methyl derivatives have higher thermal stability. So it can be said that the nitro group has provided higher thermal stability rather than chloro, fluoro and methyl groups for cured epoxy resin. As a result, benzylidene 4-hydroxycoumarin derivatives bring high thermal stability to cured epoxy resin due to having aromatic rings

In this study, polymer nanocomposites based on 2-aminophenol and Palm date have been introduced as an efficient and inexpensive catalyst and successfully used for the synthesis of benzylidene Bis(4-Hydroxycoumarin) derivatives. The polymer and nanocomposite were characterized by a Scanning Electron Microscope (SEM). Benzylidene Bis(4-Hydroxycoumarin) Derivatives have recently attracted much attention as an important class of heterocycles to their useful biological and pharmacological properties, herein we report a novel and efficient procedure for the synthesis of α,α′-benzylidenebis (4-hydroxycoumarin) derivatives based on the reaction of 4-hydroxycoumarin and aromatic aldehydes using polymer nanocomposites based on 2-aminophenol and Palm date as a solid heterogeneous catalyst in excellent yields (84-99%) and very short reaction time (2-5 min) in aqueous media (50%) have been described.