Synthesis And Antioxidant Activity Of Hyperbranched Molecule Bridged Hindered Phenols

A series of 1.0G hyperbranched molecules with series long-chain fatty amine as cores and amino as terminal groups were synthesized by Michael addition reaction and amidation condensation reaction with series Long-chain fatty amines as materials. A series of hyperbranched bridged hindered phenols were synthesized using 1.0G hyperbranched molecules as bridged groups and using β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl chloride as antioxidant groups by grafting reaction, which have two phenolic hydroxyl antioxidant groups at one end and have a long chain alkyl at the other end. At the same time, A series of aliphatic diamine bridged hindered phenols were synthesized using aliphatic diamines as bridged groups and using β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl chloride as antioxidant functional groups, which have symmetrical structure. The hyperbranched molecule bridged hindered phenols and aliphatic diamine bridged hindered phenols were characterized by FT-IR and 1HNMR. The molecular structure of the antioxidants are proved to match with the designing molecular.On the basis of the synthesis, the antioxidant properties of a series of hindered phenolic antioxidants were evaluated by the DPPH assay and the oxygen uptake measurement, and the scavenging reaction kinetics were investigated. The results of scavenging DPPH· reaction showed that a series of hyperbranched molecule bridged hindered phenols and a series of aliphatic diamine bridged hindered phenols had good scavenging effect. The scavenging rate increased first, and then decreased with increasing of the concentration of phenolic hydroxyl and the reaction time. The abilities donating hydrogen atoms to free radicals decreased with the increase of the core alkyl chain of the hyperbranched molecule, and the scavenging activity of hindered phenols on DPPH· decreased. With increasing of the length of the bridged groups, the scavenging abilities of aliphatic diamine bridged hindered phenols decrease. Moreover, the scavenging activity of a series of aliphatic diamine bridged hindered phenols was more than those of a series of hyperbranched bridged hindered phenols. The results of oxygen uptake measurement showed that the hyperbranched molecule bridged hindered phenols and the aliphatic diamine bridged hindered phenols had good scavenging effect on ROO·. With the increase of the length of the alkyl chain in the bridged groups, the rate constant of the inhibit reaction(kinh) decreased. The inhibiting ability of a series of aliphatic diamine bridged hindered phenols on ROO· was higher than that of a series of hyperbranched molecule bridged hindered phenols.