Since its invention by Dr. John T. Gleaves (then at Monsanto Company) in late 1980s,[1] TAP has been used to study a variety of industrially and academically relevant catalytic reactions, bridging the gap between surface science experiments and applied catalysis.[2] The state-of-the-art TAP installations (TAP-3) do not only provide better signal-to-noise ratio than the first generation TAP machines (TAP-1), but also allow for advanced automation and direct coupling with other techniques.
Hardwareedit
TAP instrument consists of a heated packed-bed microreactor connected to a high-throughput vacuum system, a pulsing manifold with fast electromagnetically-driven gas injectors, and a Quadrupole Mass Spectrometer (QMS) located in the vacuum system below the micro-reactor outlet.
Experimentsedit
In a typical TAP pulse-response experiment, very small (~10−9 mol) and narrow (~100 μs) gas pulses are introduced into the evacuated (~10−6torr) microreactor containing a catalytic sample. While the injected gas molecules traverse the microreactor packing through the interstitial voids, they encounter the catalyst on which they may undergo chemical transformations. Unconverted and newly formed gas molecules eventually reach the reactor's outlet and escape into an adjacent vacuum chamber, where they are detected with millisecond time resolution by the QMS. The exit-flow rates of reactants, products and inert molecules recorded by the QMS are then used to quantify catalytic properties and deduce reaction mechanisms. The same TAP instrument can typically accommodate other types of kinetic measurements, including atmospheric pressure flow experiments (105Pa), Temperature-Programmed Desorption (TPD), and Steady-State Isotopic Transient Kinetic Analysis (SSITKA).
Data analysisedit
The general methodology of TAP data analysis, developed in a series of papers by Grigoriy (Gregory) Yablonsky[3][4] ,[5] is based on comparing an inert gas response which is controlled only by Knudsen diffusion with a reactive gas response which is controlled by diffusion as well as adsorption and chemical reactions on the catalyst sample. TAP pulse-response experiments can be effectively modeled by a one-dimensional (1D) diffusion equation with uniquely simple combination of boundary conditions.
Referencesedit
^J. T. Gleaves, J. R. Ebner, T. C. Kuechler, Catal. Rev. Sci. Eng. 30 (1988) 49
^J. T. Gleaves, G. S. Yablonsky, X. Zheng, R. Fushimi, P. L. Mills, J. Mol. Calat. A Chem. 315 (2010) 108-134
^J. T. Gleaves, G. S. Yablonsky, P. Phanawadee, Y. Schuurman, Appl. Catal. A Gen. 160 (1997) 55–88
^S. O. Shekhtman, G. S. Yablonsky, S. Chen, J. T. Gleaves, Chem. Eng. Sci. 54 (1999)
^D. Constales, G. S. Yablonsky, G. B. Marin, J. T. Gleaves, Chem. Eng. Sci 56 (2001) 133–149
January 01, 1970
temporal, analysis, products, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, jsto. This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Temporal analysis of products news newspapers books scholar JSTOR January 2023 Learn how and when to remove this message Temporal Analysis of Products TAP TAP 2 TAP 3 is an experimental technique for studying the kinetics of physico chemical interactions between gases and complex solid materials primarily heterogeneous catalysts The TAP methodology is based on short pulse response experiments at low background pressure 10 6 102 Pa which are used to probe different steps in a catalytic process on the surface of a porous material including diffusion adsorption surface reactions and desorption Contents 1 History 2 Hardware 3 Experiments 4 Data analysis 5 ReferencesHistory editSince its invention by Dr John T Gleaves then at Monsanto Company in late 1980s 1 TAP has been used to study a variety of industrially and academically relevant catalytic reactions bridging the gap between surface science experiments and applied catalysis 2 The state of the art TAP installations TAP 3 do not only provide better signal to noise ratio than the first generation TAP machines TAP 1 but also allow for advanced automation and direct coupling with other techniques Hardware editTAP instrument consists of a heated packed bed microreactor connected to a high throughput vacuum system a pulsing manifold with fast electromagnetically driven gas injectors and a Quadrupole Mass Spectrometer QMS located in the vacuum system below the micro reactor outlet Experiments editIn a typical TAP pulse response experiment very small 10 9 mol and narrow 100 ms gas pulses are introduced into the evacuated 10 6 torr microreactor containing a catalytic sample While the injected gas molecules traverse the microreactor packing through the interstitial voids they encounter the catalyst on which they may undergo chemical transformations Unconverted and newly formed gas molecules eventually reach the reactor s outlet and escape into an adjacent vacuum chamber where they are detected with millisecond time resolution by the QMS The exit flow rates of reactants products and inert molecules recorded by the QMS are then used to quantify catalytic properties and deduce reaction mechanisms The same TAP instrument can typically accommodate other types of kinetic measurements including atmospheric pressure flow experiments 105 Pa Temperature Programmed Desorption TPD and Steady State Isotopic Transient Kinetic Analysis SSITKA Data analysis editThe general methodology of TAP data analysis developed in a series of papers by Grigoriy Gregory Yablonsky 3 4 5 is based on comparing an inert gas response which is controlled only by Knudsen diffusion with a reactive gas response which is controlled by diffusion as well as adsorption and chemical reactions on the catalyst sample TAP pulse response experiments can be effectively modeled by a one dimensional 1D diffusion equation with uniquely simple combination of boundary conditions References edit J T Gleaves J R Ebner T C Kuechler Catal Rev Sci Eng 30 1988 49 J T Gleaves G S Yablonsky X Zheng R Fushimi P L Mills J Mol Calat A Chem 315 2010 108 134 J T Gleaves G S Yablonsky P Phanawadee Y Schuurman Appl Catal A Gen 160 1997 55 88 S O Shekhtman G S Yablonsky S Chen J T Gleaves Chem Eng Sci 54 1999 D Constales G S Yablonsky G B Marin J T Gleaves Chem Eng Sci 56 2001 133 149 Retrieved from https en wikipedia org w index php title Temporal analysis of products amp oldid 1219037521, wikipedia, wiki, book, books, library,
