Glass Fiber Based Catalytic Material for Highly Selective Hydrogenation of Acetylene Review
Source | Advances in Materials Science Research: Volume 36 Monography, Nova Science Publishers, Inc. New York.2019. 233 c. ISBN 9781536148480. |
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Output data | Year: 2019, Volume: 36, Pages: 1-43 Pages count : 43 | ||
Tags | glass fiber, diffusion, viscosity, palladium, acetylene hydrogenation, selectivity | ||
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Funding (1)
1 | Ministry of Science and Higher Education of the Russian Federation | ГЗ-2017-2020 |
Abstract:
Selective hydrogenation of acetylene-ethylene feedstocks is an efficient way for the production of the polymer grade ethylene. The Pd catalysts show good performance in the selective hydrogenation of acetylene but at high conversions the reaction selectivity noticeably drops. To improve the selectivity, the second metal (Ag, Cu) is added in order to prevent strong multiplet adsorption of acetylene and ethylene leading to undesirable formation of ethane and higher hydrocarbons (green oil). In the present work, a novel fiberglass (FG) catalyst with highly dispersed 1-2 nm Pd clusters confined in the bulk of fiberglass at a depth of 10 nm was proposed. In spite of extremely low palladium content (0.02%), this catalyst showed very high performance in the selective hydrogenation of acetylene. Basic research of physicochemical properties of the silicate glass as well as the Pd/FG catalyst revealed that i) mass transfer of reagents in the bulk of glass does not limit the reaction rate; ii) the glass has a capability to absorb (dissolve) a large amount of polar or readily polarizable molecules like acetylene but not ethylene. Namely, this ability was responsible for high selectivity toward ethylene at complete conversion of acetylene (ethylene increment was around 60%). In other words, gas phase ethylene does not dissolve in the glass, therefore it is not involved in the selective hydrogenation of acetylene at all. A SSITKA study using 13C2H2 clearly confirmed that ethane is produced solely from acetylene in spite of a high excess of ethylene.To increase the activity, the pristine fiberglass was modified with tetramethylammonium (TMA) hydroxide. As a result, a thin layer of the new phase with lower density and viscosity was formed on the surface of glass fiber. The prepared Pd/N-FG catalyst was characterized by a higher Pd dispersion and showed a 4-fold increase in the TOF value. The measured TOF values were found to be quite similar for the catalysts with different Pd dispersion, including bimetallic ones. It means that selective hydrogenation of acetylene is the structure-insensitive reaction. Moreover, the Pd/FG catalyst is characterized by low oligomerization susceptibility, which provides its high resistance to deactivation.
Cite:
Bal’zhinimaev B.S.
Glass Fiber Based Catalytic Material for Highly Selective Hydrogenation of Acetylene
Monography chapter Advances in Materials Science Research: Volume 36. – Nova Science Publishers, Inc., 2019. – C.1-43. – ISBN 9781536148480.
Glass Fiber Based Catalytic Material for Highly Selective Hydrogenation of Acetylene
Monography chapter Advances in Materials Science Research: Volume 36. – Nova Science Publishers, Inc., 2019. – C.1-43. – ISBN 9781536148480.
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