The Catalytic Hydrogen Exchange of Aniline on Supported Metal Catalysts

Hagiwara, Hiroshi; Echigoya, Etsuro

doi:10.1246/bcsj.39.1683

Cited by 7 publications

(4 citation statements)

References 3 publications

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“…No exchange of the alkyl hydrogens in C 2 H 5 ND 2 , CH 3 ND 2 , and (CH 3 ) 2 ND had been observed by Roberts et al in 1939 over reduced nickel catalyst at 20−195 °C . Hagiwara and Echigoya studied H/D exchange with aniline over Pt and Ni; their results indicate that H atoms in the amino group exchange faster than those at the benzene ring …”

Section: Discussionmentioning

confidence: 91%

H/D Exchange of Amines and Acetonitrile over Transition Metal Catalysts

Huang

Sachtler

1998

J. Phys. Chem. B

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H/D exchange of acetonitrile, mono-, di-, and triethylamine was carried out at 75 °C over zeolite supported transition metal catalysts in a fixed-bed microflow reactor. In order to identify the location of the D atoms, the product of this primary exchange was, subsequently, subjected to secondary exchange with liquid D2O, which affects exclusively the N-bonded hydrons. 1H-NMR and mass spectrometry were used for product analysis. The results reveal a rather dramatic difference in exchange behavior between ruthenium and the group of metals including Pt, Pd, and Ni, while Rh displays an intermediate behavior. Pt, Pd, and Ni show stepwise exchange starting with the N-bonded hydrons. In contrast, multiple exchange is found for Ru; this exchange leads to preferential formation of d3 acetonitrile. With primary, secondary, and tertiary amines, the hydrons bonded to the methylene C atom are most rapidly exchanged over Ru, followed by the hydrons in methyl groups. Surprisingly, the N-bonded hydrons are only negligibly exchanged over Ru. For instance, the d2 product of ethylamine has its two D atoms predominantly in the methylene, NOT the amine group. With diethylamine, products up to d10 are abundant, but d11 is negligible. The results are rationalized on the basis of the known high propensity of ruthenium to form CRu double bonds. In contrast, formation of NRu bonds appears negligible under the conditions used.

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Section: Discussionmentioning

confidence: 91%

H/D Exchange of Amines and Acetonitrile over Transition Metal Catalysts

Huang

Sachtler

1998

J. Phys. Chem. B

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“…H/D exchange of ethylamine on zeolite NaY-supported transition-metal catalysts has been studied using NMR and mass spectrometry, and it was concluded that the main product for a Pt/NaY catalyst is CH 3 CH 2 NHD, which supports our findings for the coadsorption experiment. The preferential H/D exchange of amine over alkyl groups on Pt catalysts has also been observed for diethylamine and aniline . On the other hand, H/D exchange of alkylamines on Ru catalysts has been found to occur at the methylene group …”

Section: Discussionmentioning

confidence: 83%

“…The preferential H/D exchange of amine over alkyl groups on Pt catalysts has also been observed for diethylamine 46 and aniline. 47 On the other hand, H/D exchange of alkylamines on Ru catalysts has been found to occur at the methylene group. 46 5.3.…”

Section: Discussionmentioning

confidence: 99%

Spectroscopic Identification of Surface Intermediates in the Dehydrogenation of Ethylamine on Pt(111)

et al. 2013

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Reflection absorption infrared spectroscopy, temperature-programmed desorption, and density functional theory (DFT) have been used to study the surface chemistry and thermal decomposition of ethylamine (CH 3 CH 2 NH 2 ) on Pt(111). Ethylamine adsorbs molecularly at 85 K, is stable up to 300 K, and is partially dehydrogenated at 330 K to form aminovinylidene (CCHNH 2 ), a stable surface intermediate that partially desorbs as acetonitrile (CH 3 CN) at 340−360 K. DFT simulations using various surface models confirm the structure of aminovinylidene. Upon annealing to 420 K, undesorbed aminovinylidene undergoes further dehydrogenation that results in the scission of the remaining C−H bond and the formation of a second surface intermediate called aminoethynyl with the structure CCNH 2 , bonded to the surface through both C atoms. The assignment of this intermediate species is supported by comparison between experimental and simulated spectra of the isotopically labeled species. Further annealing to temperatures above 500 K shows that the C−N bond remains intact as the desorption of HCN is observed.

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“…Further examples of double-bond isomerisation in cyclo-octatetraene derivatives have been examined by n.m.r. spectroscopy.l57 Cyclo-octatetraene reacts with cyanonitrene to give both the 1,Z-and 1,4-adducts ( 157) and (158); it was suggested that these are respectively the products of addition of singlet and triplet cyanonitrene species.158 Dicyclo-octatetraeno[1,2 : 4,5]benzene (159), a potentially aromatic 18n-electron system, has been synthesised 159 by the reaction of 7,8-dimethylene-1,3,5-cyclo-octatriene (137) with 1,Zdehydrocyclo-octatetraene, (159) shows no evidence of aromatic character in the eight-membered rings and the n.m.r. chemical shifts of the nonbenzenoid protons are similar to those of the non-benzenoid protons of benzocyclo-octatetraene.…”

Section: (153)mentioning

confidence: 99%