Hydrogénation catalytique sous pression

Jenck, Jean; Germain, Jean-Eugène

doi:10.1051/jcp/1978750810

Cited by 8 publications

(12 citation statements)

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“…According to Tanaka and Col. ( 7 ) the intercept is referred to as a** and is related to the substrate size. The slope is referred to as KT and is related to the catalyst properties, and the relative reactivity RMSIS is expressed as : This is consistent with the equation [l] , where RMSIS is related to KMS,S According to Germain and Jenck (13), when the surface reaction between the However it should be noted in FIG. 3 that It should be noted that there is a compensating effect between the values of u** and KT in Table 11.…”

Section: ( 2 )supporting

confidence: 63%

AlPO₄‐Supported nickel catalysts. IV.‐Substituent effects in competitive hydrogenation of styrene and its α‐methyl derivative

Campelo

García

Luna

et al. 1983

Bulletin des Soc Chimique

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SUMMARY t e d o v e r a series o f n i c k e l c a t a l y s t s s u p p o r t e d on t h e AlpO4, A1P04-A12i33 andAlP04-Si02 systems, u s i n g methanol a s s o l v e n t , under i n i t i a l hydrogen p r e s s u r e i n t h e range 0.4-0.6 MPa and t e m p e r a t u r e s between 288 and 323 K , o b t a i n i n g t h e r e l a t i v e r e a c t i v i t i e s RWS,S and t h e r e l a t i v e a d s o r p t i o n c o n s t a n t s KMS s. The and K M S ,~ v a l u e s were less t h a n u n i t y i n t h e range 0.04-0.08 i n d i c a t i n g &csS was adsorbed more s t r o n g l y and less h i n d e r e d on t h e s e c a t a l y s t s t h a n MS. With r e s p e c t t o t h e i n f l u e n c e of t e m p e r a t u r e and p r e s s u r e on c o m p e t i t i v e hydrogenation, t h e r e l a t i v e r e a c t i v i t y R M s , s was found t o b e independent of t h e i n i t i a l Hydrogen p r e s s u r e w h i l e t h e changes of RMs,@ w i t h t e m p e r a t u r e followed and Arrhenius-type law below a t e m p e r a t u r e l i m i t .

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Section: ( 2 )supporting

confidence: 63%

AlPO₄‐Supported nickel catalysts. IV.‐Substituent effects in competitive hydrogenation of styrene and its α‐methyl derivative

Campelo

García

Luna

et al. 1983

Bulletin des Soc Chimique

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“…The analysis of the HREEL spectra of crotonaldehyde using the vibrational frequencies and intensities from DFT leads to the identification of five structures matching the experimental data. These structures, i.e., the η 2 -diσ(CC)-E-(s)-trans, η 2 -diσ(CC)-E-(s)-cis, η 3 -diσ(CC)-σ(O)-E-(s)-cis, η 4 diσ(CC)-diσ(CO)-E-(s)-trans, and η 4 -π(CC)-diσ(CO)-E-(s)-cis complexes, have very similar stabilities (-69 to -80 kJ/mol (for schemes of the η 1 -η 4 adsorption configurations, see Figure 1…”

Section: Resultsmentioning

confidence: 99%

Adsorption and Vibrations of α,β-Unsaturated Aldehydes on Pt(111) and Pt−Sn Alloy (111) Surfaces. 3. Adsorption Energy vs Adsorption Strength

et al. 2009

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Recently we presented high-resolution electron energy loss spectroscopy (HREELS) and temperatureprogrammed desorption (TPD) studies on the adsorption of prenal (3-methyl-2-butenal) and crotonaldehyde (2-butenal) on Pt(111) and on ultrathin Pt 3 Sn/Pt(111) and Pt 2 Sn/Pt(111) surface alloys. Vibrational studies employing HREELS have been analyzed with the help of extensive density functional theory (DFT) calculations of the energetic, structural, and vibrational properties of a large set of stable adsorption configurations. We were able to identify various adsorbate structures ranging from low hapticity η 1 -top and η 2 -diσ(CC) to flat η 4 types present in mixed phases below room temperature on these substrates. Completing this study, we now analyze common features and differences between the two molecules on the three surfaces. The key finding is that the adsorption energy turns out to be an unsatisfying measure of the interaction strength of such complex molecules on surfaces. For several identified structures lower desorption temperatures and smaller adsorption energies from DFT corroborated a weaker adsorption strength; however, vibrational and geometric properties obtained consistently from experiments and theory pointed to similarly strong molecule-surface bonding. We will show here that this phenomenon can only be rationalized by clearly differentiating between adsorption energy and interaction energy. Since the adsorption process includes significant relaxations of surface metal atoms and adsorbed molecules to optimize their covalent interactions, there is a deviation between the adsorption strength, measured by the interaction energy, and the final adsorption energy where the endothermic energetic costs of both relaxation processes have to be taken into account. Calculating these properties from DFT, we can show that adsorption energies may indeed decrease while the overall interaction energy of a molecule with a surface can, nonetheless, increase. The adsorption energy is hence not a good, unambiguous measure of molecule-surface interactions.

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“…Indeed, initial conversion determined at the first two minutes increases from 4. 5 [41][42][43]. As reported by several authors [44,45], deactivation could be due to coverage of a portion of the active sites by coke formation and/or chemisorption of CO formed by decomposition of crotonaldehyde or the unsaturated alcohol.…”

Section: Crotonaldehyde Hydrogenationmentioning

confidence: 99%

“…The unsaturated alcohols obtained by selective hydrogenation of the C=O group of α,β-unsaturated aldehydes are a very important intermediate for the production of perfumes, flavours, and pharmaceuticals [1][2][3][4]. The selective hydrogenation of the carbonyl bond in the presence of an olefinic bond [5] is very difficult because the C=C group hydrogenation is thermodynamically and kinetically favored [6][7][8]. Thus, monometallic catalysts supported on Al 2 O 3 and SiO 2 led mostly to the formation of saturated aldehyde [9].…”

mentioning

confidence: 99%

Rh/ZnO-Al2O3 Catalysts for Selective Hydrogenation of Crotonaldehyde

Aoun¹,

Benamar²,

Chater³

2011

Chinese Journal of Catalysis

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Hydrogénation catalytique sous pression

Cited by 8 publications

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AlPO₄‐Supported nickel catalysts. IV.‐Substituent effects in competitive hydrogenation of styrene and its α‐methyl derivative

AlPO₄‐Supported nickel catalysts. IV.‐Substituent effects in competitive hydrogenation of styrene and its α‐methyl derivative

Adsorption and Vibrations of α,β-Unsaturated Aldehydes on Pt(111) and Pt−Sn Alloy (111) Surfaces. 3. Adsorption Energy vs Adsorption Strength

Rh/ZnO-Al2O3 Catalysts for Selective Hydrogenation of Crotonaldehyde

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Hydrogénation catalytique sous pression

Cited by 8 publications

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AlPO4‐Supported nickel catalysts. IV.‐Substituent effects in competitive hydrogenation of styrene and its α‐methyl derivative

AlPO4‐Supported nickel catalysts. IV.‐Substituent effects in competitive hydrogenation of styrene and its α‐methyl derivative

Adsorption and Vibrations of α,β-Unsaturated Aldehydes on Pt(111) and Pt−Sn Alloy (111) Surfaces. 3. Adsorption Energy vs Adsorption Strength

Rh/ZnO-Al2O3 Catalysts for Selective Hydrogenation of Crotonaldehyde

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AlPO₄‐Supported nickel catalysts. IV.‐Substituent effects in competitive hydrogenation of styrene and its α‐methyl derivative

AlPO₄‐Supported nickel catalysts. IV.‐Substituent effects in competitive hydrogenation of styrene and its α‐methyl derivative