Hydrogen Uptake Kinetics of 1,4-Bis(phenylethynyl)benzene (DEB) Rubberized Coating on Silicone Foam Substrate

Sangalang, Elizabeth A.; Sharma, Hom N.; Saw, C. K.; Gollott, R.; Matt, Sarah M.; Wilson, Thomas S.; McLean, W.; Maxwell, Robert S.; Dinh, L. N.

doi:10.1021/acsami.9b20235

Cited by 16 publications

(21 citation statements)

References 28 publications

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“…However, these triple-bonded organic hydrogen getters require the presence of a catalyst (in this case, palladium) to break molecular hydrogen down to atomic hydrogen, which can then react with the triple bonds. One well-studied example of this class of getters is 1,4-bis(phenylethynyl)benzene, abbreviated DEB. − DEB readily reacts with atomic hydrogen and safely traps the hydrogen in the solid material, thus preventing reaction with other components or overpressure from accumulation in a closed space.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Uptake Kinetics of 1,4-Bis(phenylethynyl)benzene Rubberized O-Rings: Measurements, Modeling, and Comparison with Additional Forms of Organic Getters

et al. 2022

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A class of molecules called “hydrogen getters” can react with, or scavenge, H2 in applications where the hydrogen presence and/or buildup are not desirable. One such “getter”, 1,4-bis(phenylethynyl)benzene or DEB, can be incorporated into a silicone matrix in the form of an O-ring for added flexibility, environmental resiliency, and convenient use as a gasket in sealed applications. However, the performance and kinetics of this DEB-loaded rubberized O-ring have not yet been characterized. In this work, the hydrogen uptake kinetics of the rubberized DEB O-ring were extracted by the isoconversional analysis from isothermal isobaric data under conditions of 13,332 Pa H2 and 305–325 K. The isoconversional and cylindrical diffusion approximations were then used to predict and model the hydrogen uptake of rubberized DEB O-rings under any arbitrary condition, as illustrated in this work for the simple case of a constant rate of hydrogen generation/input. In comparison with other Pd/carbon-based/organic getter systems, these rubberized DEB O-rings provide a type of hydrogen getter material with enhanced flexibility and catalyst protection in applications where an O-ring seal is needed.

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Section: Introductionmentioning

confidence: 99%

Hydrogen Uptake Kinetics of 1,4-Bis(phenylethynyl)benzene Rubberized O-Rings: Measurements, Modeling, and Comparison with Additional Forms of Organic Getters

et al. 2022

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“…On a microscopic scale, the exothermic nature of the scavenging reaction induces a local temperature rise, providing the saturated DEB molecules (near the catalyst) a kinetic energy that could allow molecular diffusion away from the Pd catalyst surface. Therefore, unsaturated DEB molecules are expected to migrate toward the catalyst surface, ,, which enhances the hydrogenation rate. However, when the reaction is performed at low H 2 pressures (<2667 Pa), the consequent slower rate induces only low local temperature rise that is not sufficient for the DEB molecules to diffuse .…”

Section: Results and Discussionmentioning

confidence: 99%

Catalyst Surface Dispersion: Insights into Hydrogenation Kinetics and Mechanism

Lavi

Ruse²,

Pevzner³

et al. 2020

J. Phys. Chem. C

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Catalyst-driven hydrogenation of an unsaturated organic matrix is commonly used for irreversible scavenging of hydrogen. The effect of catalyst dispersion on the hydrogenation reaction was explored as a means to deciphering the hydrogenation mechanism. The hydrogenation rate was thus measured in a model system consisting of a composite of a graphene nanoplatelet (GNP)-supported catalyst (Pd) in an organic matrix comprising the hydrogen scavenger 1,4-di(phenylethynyl)benzene (DEB). A similar activated carbon (AC)-supported Pd system in a DEB matrix was used as a reference system. We found that the rate of the hydrogenation reaction was limited by the migration of hydrogen atoms to the scavenger from the carbon-based catalyst support and could be manipulated by tuning (1) the specific surface area (SSA) of the catalyst support and (2) the mean catalyst-toscavenger distance (catalyst dispersion quality) in the overall composite. We integrated these two key parameters into a single design parameter, termed the catalyst surface density (CSD). We found that for catalyst particles smaller than 100 nm the rate-determining step of the hydrogenation reaction was mainly dictated by the quality of the catalyst dispersion, expressed by the CSD parameter.Manipulating the CSD at a fixed composite composition yielded up to 7-fold acceleration in the hydrogenation rate, which is identical to the effect of increasing the concentration of the expensive and heavy catalyst by the same factor.

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“…A simulation of the actual H 2 pressure buildup, when H 2 is injected at a constant rate into the reaction vessel containing the DPB pellets, is given by eq …”

Section: Materials and Methodsmentioning

confidence: 99%

Phase Change-Driven Negative Activation Energies in Pd/Carbon-Based/Organic Getter Hydrogenation Reactions

et al. 2020

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The hydrogenation of 1,4-diphenylbutadiyne (DPB) blended with carbon-supported Pd (DPB−Pd/C) in the form of pellets was investigated by isothermal−isobaric experiments at 1333 Pa of H 2 and in the temperature range of 291−315 K. The extracted kinetics were then used in conjunction with a complementary constant rate of H 2 input experimentation to model the performance of a DPB-catalysis/support system as a function of temperature and H 2 partial pressure. First-principles density functional theory (DFT) calculations were also performed to shed light on the molecular level energetics of DPB and its intermediate states. A seemingly puzzling formation of alternate positive activation energy barrier (higher reaction rate with higher temperature) and negative activation energy barrier (higher reaction rate with lower temperature) zones during the hydrogenation process was discovered. However, this observed phenomenon can be logically explained in terms of the associated phase changes and H 2 transport in the material. This work provides a good illustration of a rarely encountered chemical process with a negative activation energy barrier.

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Hydrogen Uptake Kinetics of 1,4-Bis(phenylethynyl)benzene (DEB) Rubberized Coating on Silicone Foam Substrate

Cited by 16 publications

References 28 publications

Hydrogen Uptake Kinetics of 1,4-Bis(phenylethynyl)benzene Rubberized O-Rings: Measurements, Modeling, and Comparison with Additional Forms of Organic Getters

Hydrogen Uptake Kinetics of 1,4-Bis(phenylethynyl)benzene Rubberized O-Rings: Measurements, Modeling, and Comparison with Additional Forms of Organic Getters

Catalyst Surface Dispersion: Insights into Hydrogenation Kinetics and Mechanism

Phase Change-Driven Negative Activation Energies in Pd/Carbon-Based/Organic Getter Hydrogenation Reactions

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