title: Catalytic reduction of 4-nitrophenol with gold nanoparticles synthesized by caffeic acid.
abstract: In this study, various concentrations of caffeic acid (CA) were used to synthesize gold nanoparticles (CA-AuNPs) in order to evaluate their catalytic activity in the 4-nitrophenol reduction reaction. To facilitate catalytic activity, caffeic acid was removed by centrifugation after synthesizing CA-AuNPs. The catalytic activity of CA-AuNPs was compared with that of centrifuged CA-AuNPs (cf-CA-AuNPs). Notably, cf-CA-AuNPs exhibited up to 6.41-fold higher catalytic activity compared with CA-AuNPs. The catalytic activity was dependent on the caffeic acid concentration, and the lowest concentration (0.08 mM) produced CA-AuNPs with the highest catalytic activity. The catalytic activities of both CA-AuNPs and cf-CA-AuNPs decreased with increasing caffeic acid concentration. Furthermore, a conversion yield of 4-nitrophenol to 4-aminophenol in the reaction mixture was determined to be 99.8% using reverse-phase high-performance liquid chromatography. The product, 4-aminophenol, was purified from the reaction mixture, and its structure was confirmed by1H-NMR. It can be concluded that the removal of the reducing agent, caffeic acid in the present study, significantly enhanced the catalytic activity of CA-AuNPs in the 4-nitrophenol reduction reaction.
authors.affiliation: College of Pharmacy and Inje Institute of Pharmaceutical Sciences and Research, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea.
authors.forename: Yu Seon
authors.initials: YS
authors.lastname: Seo
authors.affiliation: College of Pharmacy and Inje Institute of Pharmaceutical Sciences and Research, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea.
authors.forename: Eun-Young
authors.initials: EY
authors.lastname: Ahn
authors.affiliation: College of Pharmacy and Inje Institute of Pharmaceutical Sciences and Research, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea.
authors.forename: Jisu
authors.initials: J
authors.lastname: Park
authors.affiliation: College of Pharmacy and Inje Institute of Pharmaceutical Sciences and Research, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea.
authors.forename: Tae Yoon
authors.initials: TY
authors.lastname: Kim
authors.affiliation: College of Pharmacy and Inje Institute of Pharmaceutical Sciences and Research, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea.
authors.forename: Jee Eun
authors.initials: JE
authors.lastname: Hong
authors.affiliation: Department of Pharmaceutical Engineering, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea.
authors.forename: Kyeongsoon
authors.initials: K
authors.lastname: Kim
authors.affiliation: College of Pharmacy and Inje Institute of Pharmaceutical Sciences and Research, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea. yohanpark@inje.ac.kr.
authors.forename: Yohan
authors.initials: Y
authors.lastname: Park
authors.affiliation: College of Pharmacy and Inje Institute of Pharmaceutical Sciences and Research, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea. youmiep@inje.ac.kr.
authors.forename: Youmie
authors.initials: Y
authors.lastname: Park
keywords: 4-Nitrophenol reduction reaction; Caffeic acid; Catalytic activity; Centrifugation; Gold nanoparticles