Online High Throughput Measurements for Fast Catalytic Reactions Using Time-Division Multiplexing Gas Chromatography
Online High Throughput Measurements for Fast Catalytic Reactions Using Time-Division Multiplexing Gas Chromatography
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DOI：
10.1021/acs.analchem.8b01805
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发表时间：
2018-08-07
影响因子：
7.4
通讯作者：
Trapp, Oliver
中科院分区：
文献类型：
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作者：
Wunsch, Marco R.;Lehnig, Rudolf;Trapp, Oliver
开发新型催化剂是优化化工过程的关键。因此，需要先进的分析方法来准确测定新型催化剂的催化性能。通常采用气相色谱法定量分析由特定催化剂生成的挥发性化合物的产物分布。然而，表征快速变化的催化剂，例如由于失活，仍然提出了一个分析挑战，因为气相色谱方法对于监测复杂产物光谱的变化太慢。在这里，我们开发了一种基于多路气相色谱（mpGC）概念的气相色谱技术，用于快速全面地分析催化测试装置的产品流。将该技术应用于甲醇制烯烃（MTO）转化的催化反应研究。对于这种方法，选择两次测量之间的时间距离，使色谱图而不是峰本身重叠。这样，就形成了层叠色谱图，其中依次进样的洗脱液基线的组分挨个从柱上分离出来。来自不同样品的峰是交错的，因此，该方法被称为时分复用气相色谱（td-mpGC）。峰是通过直接峰积分来分析的，不需要像许多mpGC应用程序那样对原始数据进行Hadamard变换来反卷积。因此，样品可以等距注入。积分峰必须分配给正确的保留时间。研究MTO催化剂的反应周期和再生周期的时间间隔分别为4.3 min和38 s。柱切换技术，如反冲洗和心脏切割介绍了通用工具的复用气相色谱。
Developing new catalysts is crucial for optimization of chemical processes. Thus, advanced analytical methods are required to determine the catalytic performance of new catalysts accurately. Usually, gas chromatographic methods are employed to analyze quantitatively the product distribution of volatile compounds generated by a specific catalyst. However, the characterization of rapidly changing catalysts, e.g., due to deactivation, still poses an analytical challenge because gas chromatographic methods are too slow for monitoring the change of the complex product spectra. Here, we developed a gas chromatographic technique based on the concept of multiplexing gas chromatography (mpGC) for fast and comprehensive analysis of the product stream from a catalytic testing unit. This technique is applied for the study of the catalytic reaction of methanol-to-olefins (MTO) conversion. For this method, the time distance between two measurements is chosen so that the chromatograms but not the peaks themselves are superimposed. In this way, stacked chromatograms are generated in which the components from successively injected samples elute baseline separated next to each other from the column. The peaks from different samples are interlaced, and for this reason, the method is referred to as time-division multiplexing gas chromatography (td-mpGC). The peaks are analyzed by direct peak integration not requiring a Hadamard transformation for deconvolution of the raw data as usual for many mpGC applications. Therefore, the sample can be injected equidistantly. The integrated peaks have to be allocated to the correct retention times. The time distance between two measurements for studying the reaction and regeneration cycles of MTO catalysts is 4.3 min and 38 s, respectively. Column switching techniques such as back-flush and heart-cut are introduced as general tools for multiplexing gas chromatography.