Synthesis Of Thermal Oxygen And Lightanti-aging Agent And Study Its Effectin NR Vulcanizates

Piperazine-1, 4-dipropanoic acid dimethyl ester was synthesized through Michael addition between piperazine hexahydrate and methyl acrylate catalyzed by graphene oxide in water. Then, this compound was combinated with 1, 2, 2, 6, 6-pentamethyl-4-piperidinol via transesterification reaction catalyzed by sodium methoxide, yielding piperazine- 1, 4-dipropanoic acid di-(1, 2, 2, 6, 6-pentamethyl-4-piperidine) yl ester, which has good compatibility with resin and can improve the durability in nature rubber. The process variables affecting the transesterification reaction such as molar ratio, catalyst dosage, reaction time, and reaction temperature were investigated and optimized from economic benefits. Finally, the optimal reaction conditions were 150℃ for a reaction time of 12 h, 2.0% CH3ONa(w/w of substrates) and 1: 2.2 molar ratio of ester / alcohol in the presence of 3A molecular sieves in anhydrous toluene. The yield of the piperazine- 1, 4-dipropanoic acid di-(1, 2, 2, 6, 6-pentamethyl-4-piperidine) yl ester under optimal condition was 92.0%. The structures of all products were confirmed by Fourier transformed infrared(FT-IR) spectroscopy, elemental analysis and mass spectrometry nuclear magnetic resonance(1H-NMR and 13C-NMR) spectrometry. The thermal stability was assessed by therm al analysis. Piperazine- 1, 4-dipropanoic acid di-(1, 2, 2, 6, 6-pentamethyl-4-piperidine) yl ester was mixed with nature rubber to evaluate its anti-aging effect by testing the change of hardness, tensile strength and elongation at break before and after aging at different content and aging time, and compared with the commercial antioxidant Tinuvin770. The results showed that piperazine- 1, 4-dipropanoic acid di-(1, 2, 2, 6, 6-pentamethyl-4-piperidine) yl ester was found to be good stabilizer in NR vulcanizates in comparison with Tinuvin770.