RSC Advances p. 42423 - 42431 (2020)
Update date:2022-08-24
Topics:
Dong, Jinfeng
Luo, Ruidong
Luo, Yunbai
We first synthesized a diblock copolymer poly[tert-butyl methacrylate]-b-poly[3-(trimethoxysilyl)propyl methacrylate] (PtBMA-b-PTMSPMA) through reversible addition-fragmentation chain transfer (RAFT) living radical polymerization and grafted it onto fumed silica by converting the PTMSPMA segment to silanol and the PtBMA segment to polymethylacrylic acid (PMAA) in the presence of trifluoroacetic acid in order to obtain PMAA brush-coated silica nanoaggregates P-Si. TEM, DLS, FTIR, and TGA results confirmed the successful modification of the starting materials. The nanoaggregates flocculated and stabilized a toluene-in-water Pickering emulsion at low pH, while the nanoaggregates were well dispersed in water and broke the emulsion under both neutral and basic conditions. Alternatively, the addition of acid/base induced emulsification/demulsification cycles that were sustained for several cycles. Moreover, when the P-Si was mixed with Rh-loaded silica, Rh-Si, the mixture had the same pH-responsive Pickering emulsion behavior as the single P-Si. This Pickering emulsion system can be used in the biphasic interfacial catalytic hydrogenation of olefins and had excellent yields under a hydrogen atmosphere. The yield of Pickering emulsion catalysis rapidly reached more than 99% in 3 h, while that of the demulsified mixture failed to reach 20% in 4 h, which verified the promotion of catalysis by the Pickering emulsion. Base-induced demulsification can be used to separate the products and recycle the catalyst. This pH-responsive Pickering emulsion catalytic system was capable of several cycles of reuse, and there was no significant decrease in catalytic efficiency even after eight cycles. This journal is
View MoreChengdu NoVi Biotechnology Co., Ltd.
Contact:13551243286/028-81458053
Address:NO.168-1-224 JULONG ROAD WUHOU DISTRICT, CHENGDU CITY,SICHUAN PROVINCE
Yangzhou Zhongbao Pharmaceutical Co.,Ltd
Contact:+86-514-88290838
Address:Jiangsu Baoying county economic develpment zone in baoying avenue91
Shanghai Xinda Pharmaceuticals Co., Ltd.
Contact:86-21-33692333-8008
Address:999 Linxian Road, Jinshan Industrial Park, Shanghai, China
Contact:86-574-26865651
Address:529 YuanBaoShan Road, Beilun District
Contact:+86+21-58956006 15800617331
Address:402 Room, 150# Cailun Road, Zhangjiang high tech park, Shanghai
Doi:10.1063/1.448737
(1985)Doi:10.1021/jo00837a700
(1970)Doi:10.1016/j.tetlet.2005.06.035
(2005)Doi:10.1039/c6tc02009g
(2016)Doi:10.1016/j.bmc.2009.05.053
(2009)Doi:10.1021/acs.joc.5b01117
(2015)