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Dynamics of transition-metal complex in supercritical CO_2 as studied by NMR

核磁共振研究超临界CO_2中过渡金属配合物的动力学

基本信息

批准号：
11440176
负责人：
EGUCHI Taro
金额：
$ 9.86万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11440176/
关键词：
Super-critical fluid Xenon Carbon dioxide High pressure NMR Porous materials Molecular sieves Catalysis Dynamics ポリマー遷移金属錯体

项目摘要

In 1999 we designed and built a new high-pressure NMR probe which can be used in a heterogeneous system under the supercritical condition of CO_2 (T_c = 31.0℃, P_c = 72.9atm). In situ NMR measurements can be performed in a temperature range between - 70 ℃ and + 150 ℃ , and in a pressure range below 20 MPa by using this probe.^<129>Xe NMR was recorded on a Bruker MSL-200 spectrometer to investigate physico-chemical properties of micropores and/or mesopores in various porous systems. The critical parameters of Xe are Tc = 289.8 K, Pc = 5.8 MPa, and ρ_c = 1.15 gcm^<-3>.At the first stage, we studied the free volumes in polymers which can adsorb Xe very weakly. The size of the micropore in each polymer was determined by ^<129>Xe NMR and was compared with the result of the positron annihilation experiment.In the next stage, we applied the first high-pressure ^<129>Xe NMR to the meoporous silica, FSM-16. Three types of samples were used, which have different diameters (d) of the mesopore, being d = 1.9, 2.7, and 4.1 nm. It was found that there are two inequivalent Xe inside the mesopore with d = 1.9 nm. On the other hand, a single resonance line was observed in the mesopore with d = 4.1 nm. It was concluded that at least a diameter of d = 2.7 nm is necessary to detect the evidence of the critical phenomenon in the mesopore.Finally we are now studying adsorption properties of molecular sieves 5A and 13X by using high-pressure ^<129>Xe NMR. It follows that not only water molecules inside the micropores but also the particle sizes affect Xe adsorption into these molecular sieves.

1999年我们设计并制造了一种新型的高压核磁共振探针，它可以用于CO_2超临界条件下的非均相体系（T_c = 31.0℃，P_c = 72.9atm）。该探头可在-70 ℃ ~+150 ℃的温度范围内，在20 MPa以下的压力范围内进行原位核磁共振测量。<129>在Bruker MSL-200光谱仪上记录1HNMR以研究各种多孔体系中微孔和/或中孔的物理化学性质。吸附的临界参数为Tc = 289.8 K，Pc = 5.8 MPa，ρ_c = 1.15 gcm ~ 2<-3>。通过1H NMR测定了每种聚合物中的电子尺寸<129>，并与正电子湮没实验的结果进行了比较。在下一阶段，我们将第一个高压<129>1H NMR应用于介孔二氧化硅FSM-16。使用三种类型的样品，其具有不同的中孔直径（d），d = 1.9、2.7和4.1nm。结果表明，介孔中存在两个不相等的孔道，孔径d = 1.9nm。另一方面，在d = 4.1nm的介孔中观察到单一的共振线。最后，我们正在用高压1H NMR研究5A和13 X分子筛的吸附性能<129>。由此可见，不仅微孔内的水分子而且颗粒尺寸也影响到这些分子筛中的水吸附。