Perpetual hyperpolarization of allyl acetate from parahydrogen and continuous flow heterogeneous hydrogenation with recycling of unreacted propargyl acetate
Perpetual hyperpolarization of allyl acetate from parahydrogen and continuous flow heterogeneous hydrogenation with recycling of unreacted propargyl acetate
复制标题
仲氢中乙酸烯丙酯的永久超极化和连续流非均相氢化以及回收未反应的乙酸炔丙酯
DOI：
10.1016/j.jmro.2022.100076
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发表时间：
2022
影响因子：
--
通讯作者：
Bowers, Clifford R.
中科院分区：
文献类型：
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作者：
Zhao, Tommy Yunpu;Lapak, Michelle P.;Behera, Ranjan;Zhao, Hanqin;Ferrer, Maria-Jose;Weaver, Helena E.;Huang, Wenyu;Bowers, Clifford R.
介绍了一种新型的闭环连续流（CF）反应器系统，用于多相催化仲氢增强液体核磁共振（NMR），该系统能够回收未反应的液体底物反应物。该系统由一个HPLC泵，一个液体基质水库纳入气体扩散器，一个全金属填充床催化反应器，和AF-2400管中管气体渗透膜去除正常的H2。两种类型的负载型金属纳米粒子催化剂进行了测试：介孔二氧化硅封装的Pt 3Sn金属间化合物纳米粒子和Rh上的TiO 2载体。在乙酸炔丙酯到乙酸烯丙酯的CF氢化中，超极化信号在20 min的再循环中表现出稳定性，使用99% p-H2时信号增强高达626，并且催化剂到流动溶液中的浸出可忽略不计。这些结果表明，进行系统优化的条件连续流动催化和极化转移到异核生物医学磁共振成像具有重要意义的实用性。
A novel closed loop, continuous flow (CF) reactor system for parahydrogen enhanced nuclear magnetic resonance (NMR) of liquids via heterogeneous catalysis is introduced which enables recycling of unreacted liquid substrate reactant. This system consists of an HPLC pump, a liquid substrate reservoir incorporating a gas diffuser, an all-metal packed bed catalytic reactor, and an AF-2400 tube-in-tube gas permeable membrane for removal of normal H2. Two types of supported metal nanoparticle catalysts were tested: mesoporous silica encapsulated Pt3Sn intermetallic nanoparticles and a Rh on anatase TiO2support. In the CF hydrogenation of propargyl acetate to allyl acetate, the hyperpolarized signals exhibited stability over 20 min of recirculation, with signal enhancements of up to 626 using 99% p-H2and negligible leaching of the catalyst into the flowing solutions. These results demonstrate the practicality of performing systematic optimization of conditions for continuous flow catalysis and polarization transfer to heteronuclei with important implications for biomedical magnetic resonance imaging.