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排序方式: 共有748条查询结果,搜索用时 203 毫秒
1.
Yonghui Liu Huaying Gao Xiaoli Sheng Yuming Zhou Beibei Wang Xiao Sha Maolu Jin Jie Zhao Wenqi Liu 《应用有机金属化学》2019,33(11)
In this work, a series of novel acidic polymerized ionic liquids were used as heterogeneous catalyst for alkylation of o‐Xylene with styrene. And the effect of the amount of initiator and the type of acid used for ion exchange on catalyst structure and the catalytic performance of catalysts for alkylation were studied thoroughly. The experiment results show: when the percentage of the amount of initiator in the total material is 3%, the polymerized ionic liquid catalyst MPM‐SO3H‐[C3V][SO3CF3] has the most uniform with a specific surface area of 97.30 m2/g and a pore volume of 0.35 cm3/g. Benefiting from the unique structure features, MPM‐SO3H‐[C3V][SO3CF3] manifested an excellent catalytic performance for alkylation of o‐Xylene with styrene, along with the conversion of styrene was 96.8% and the yield of 1‐Phenyl‐1‐ortho‐xylene ethane was 94.7%. Therefore, this work provides a novel reference to the synthesis of polymerized ionic liquids and clearly explains the advantage of novel acidic polymerized ionic liquids on alkylation. 相似文献
2.
In this work, the interfacial mass balance relations combined with the non-parametric kinetic (NPK) analysis results were used for evaluating the thermo-chemical ablation process and oxidation mechanism of carbon aerogels with various porous structure. It was found that the two-parameter model of Nomen–Sempereis was able to describe the kinetics of the oxidation reaction and to reveal the structure-dependent contribution of two main processes with chemical and physical nature. The porosity of the carbon aerogel, rather than the other microstructural features, was realized more effective on the rate of ablation. 相似文献
3.
Microporous carbon shows the highest supercapacitor performance among other carbon nanomaterials, and thus, is considered as the most promising candidate for the fabrication of high-performance supercapacitors. However, it has puzzled the researchers as micropores do not have enough space for the formation of the so-called double layer. Several models have been proposed to explain the mechanism of energy storage by microporous supercapacitors. The most common one is that the micropores are initially filled by both anions and cations, and charging/discharging is via ion-exchange through these single row-filled micropores. Although this theory has been supported by several computational calculations, it is discussed here that this model is in disagreement with the experimental facts commonly accepted in the literature. 相似文献
4.
Zhihong Zhao Bin Wang Rui Tan Wenjing Liu Minghui Zhang 《Magnetic resonance in chemistry : MRC》2022,60(4):427-433
In this study, the transverse relaxation time (T2) of activated carbon (AC) in different relative environment humidity was detected firstly by low-field nuclear magnetic resonance (LFNMR). The pore size (diameter) of AC distributions was calculated by the relationship between T2 and surface relaxation rate (ρ), where ρ was obtained by the detection of nine porous materials with known pore size. The results showed that the pore size distributions of AC calculated by ρ < 0.19 nm/ms were in good agreement with that obtained by nitrogen adsorption method and proved that LFNMR as a new detection method was feasible for characterizing AC pore size distribution. 相似文献
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Phase pure AlPO4 with the AlPO4-18 (AEI) structure was synthesised using N,N-diisopropylethyla-mine as a template. Using a combination of X-ray powder diffraction and computational methods, the location and orientation of the N,N-diisopropylethylamine molecules inside the cages of the AEI structure were determined. Thermogravimetric analysis confirmed that the number of template molecules per unit cell was consistent with the diffraction study. We unequivocally show that only one template molecule is present in each cage of the crystalline AEI material. Our work demon-strates that a combined approach enables accurate structure resolution of such complex materials. 相似文献
7.
Fredrik Elwinger Sergey V. Dvinskikh István Furó 《Magnetic resonance in chemistry : MRC》2015,53(8):572-577
A method for measuring the ligand concentration in heterogeneous materials like chromatography media is described. In this method, 13C single pulse excitation magic angle spinning NMR experiment with broadband 1H decoupling is used to determine the peak integrals for a butyl ligand in the spectrum of a dried chromatography medium. Within a carefully controlled protocol, those integrals compared with that of the internal reference compound dimethyl sulfone provide the required volume concentration with an accuracy of ca 2%. The effects of temperature, degree of hydration, and other experimental parameters are discussed. Copyright © 2015 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd. 相似文献
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不同碱处理制备多级孔HZSM-5催化剂及噻吩烷基化性能研究 总被引:1,自引:0,他引:1
用Na2CO3、TPAOH和TPA+/CO32-混合碱分别处理HZSM-5分子筛,采用FT-IR、XRD、XRF、N2吸附脱附、SEM、NH3-TPD及Py-FTIR表征手段对各类碱处理前后的HZSM-5分子筛进行表征。结果表明,3种类型的碱处理HZSM-5分子筛后,均能形成微孔-介孔多级孔道的HZSM-5(A)催化剂,并能调变催化剂的酸性,其中,TPA+/CO32-混合碱处理得到的HZSM-5(TPA+/CO32-)催化剂,比表面积最大,介孔数量最多。在小型固定床反应器上,考察了HZSM-5和HZSM-5(A)催化剂的噻吩烷基化性能,结果表明,HZSM-5(TPA+/CO32-)催化剂因为具有适当的多级孔孔道和较多的B酸中心而表现出较高的噻吩转化率和1-己烯对噻吩的选择性。 相似文献
10.
在高温高压(1 000 ℃、12 MPa)固定床反应器上对内蒙古褐煤半焦的加氢甲烷化反应特性进行了研究,采用氮吸附和扫描电镜(SEM)对甲烷化残渣比表面积、孔结构和表面形态进行了表征。结果表明,半焦加氢甲烷化可分为加氢热解、快速加氢和慢速加氢等三个反应阶段,每阶段分别发生含氧官能团和烷基侧链加氢反应、芳环结构加氢反应以及贫氢骨架碳结构加氢反应。半焦加氢甲烷化最优反应温度为800 ℃,反应压力为3.0~4.0 MPa;提高升温速率可以缩短前段(碳转化率低于46%)反应过程时间,对后段(碳转化率高于46%)反应过程影响较小。半焦甲烷化残渣的吸附-脱附等温线呈反S型,滞后环呈H3回线形状;在甲烷化反应过程中,半焦平均孔径先减小后增大,总孔容积和介孔容积逐渐增大,微孔容积和比表面积先增大后减小。 相似文献