Ricciardi Roberto, Munirathinam Rajesh, Huskens Jurriaan, Verboom Willem
Laboratory of Molecular Nanofabrication, MESA+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands.
ACS Appl Mater Interfaces. 2014 Jun 25;6(12):9386-92. doi: 10.1021/am5017717. Epub 2014 Jun 12.
Sulfonic acid-bearing polymer brushes were grown on the inner walls of continuous flow glass microreactors and used in the acid-catalyzed hydrolysis of benzaldehyde dimethyl acetal as a test reaction. Randomly 1:1 mixed polymer brushes of poly-3-sulfopropyl methacrylate (PSPM) and poly-2-hydroxyethyl methacrylate (PHEMA) showed a 6-fold increase of the TOF value compared to the solely PSPM-containing microreactor. This remarkable improvement is attributed to the cooperative stabilizing effect of proximal OH groups on the active sulfonic acid moieties within the brush architecture. In fact, the rational mixing of SPM with methyl methacrylate (MMA) as an OH-free comonomer caused a drop in the activity of the resulting catalytic platform. A 5-fold increase of the TON of the 1:1 PSPM-PHEMA versus the PSPM homopolymer brush systems additionally demonstrates the substantial increase in the stability of the mixed brushes catalytic platform, which could be continuously run over 7 days without significant loss of activity. The 1:1 PSPM-PHEMA mixed brush catalytic system also showed a good activity in the deprotection of 2-benzyl tetrahydropyranyl ether.
磺酸基聚合物刷生长在连续流动玻璃微反应器的内壁上，并用于苯甲醛二甲缩醛的酸催化水解作为测试反应。聚甲基丙烯酸3-磺丙酯（PSPM）和聚甲基丙烯酸2-羟乙酯（PHEMA）以1:1随机混合的聚合物刷相比仅含PSPM的微反应器，其TOF值提高了6倍。这种显著的改善归因于刷状结构中近端OH基团对活性磺酸部分的协同稳定作用。事实上，将SPM与作为无OH共聚单体的甲基丙烯酸甲酯（MMA）进行合理混合会导致所得催化平台的活性下降。与PSPM均聚物刷体系相比，1:1 PSPM-PHEMA的TON增加了5倍，这进一步证明了混合刷催化平台稳定性的大幅提高，该平台可以连续运行7天而活性无明显损失。1:1 PSPM-PHEMA混合刷催化体系在2-苄基四氢吡喃醚的脱保护反应中也表现出良好的活性。
