Conformational studies by Raman spectroscopy and statistical analysis of gauche interactions in n-butylamine

Teixeira‐Dias, J. J. C.; Carvalho, Luís A. E. Batista de; Costa, A. M. Amorim da; Lampreia, Isabel M.S.; Barbosa, Ester F.G.

doi:10.1016/0584-8539(86)80139-8

Cited by 36 publications

(12 citation statements)

References 28 publications

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“…The gas phase infrared spectrum for pyrrole exhibits only two vibrational resonances in the 2700-3600 cm -1 region, an aromatic N-H stretch at 3530 cm -1 and an aromatic C-H stretch at 3128 cm -1 . 32-34 Table 2 displays vibrational resonances for pyrrole, [32][33][34][35] pyrrolidine, 36 and butylamine 37,38 in the gas phase. The appearance of vibrational modes in the C-H region below 3000 cm -1 indicates hydrogenated products exist on the surface, as pyrrole has no such vibrational modes.…”

Section: Surface Species During Reaction On Unpromoted Pt(111) and Rhmentioning

confidence: 99%

Pyrrole Hydrogenation over Rh(111) and Pt(111) Single-Crystal Surfaces and Hydrogenation Promotion Mediated by 1-Methylpyrrole: A Kinetic and Sum-Frequency Generation Vibrational Spectroscopy Study

Kliewer¹,

Bieri²,

Somorjai³

2008

J. Phys. Chem. C

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Sum-frequency generation (SFG) surface vibrational spectroscopy and kinetic measurements using gas chromatography have been used to study the adsorption and hydrogenation of pyrrole over both Pt(111) and Rh(111) single-crystal surfaces at Torr pressures (3 Torr pyrrole, 30 Torr H 2 ) to form pyrrolidine and the minor product butylamine. Over Pt(111) at 298 K it was found that pyrrole adsorbs in an upright geometry cleaving the N-H bond to bind through the nitrogen evidenced by SFG data. Over Rh(111) at 298 K pyrrole adsorbs in a tilted geometry relative to the surface through the π-aromatic system. A pyrroline surface reaction intermediate, which was not detected in the gas phase, was seen by SFG during the hydrogenation over both surfaces. Significant enhancement of the reaction rate was achieved over both metal surfaces by adsorbing 1-methylpyrrole before reaction. SFG vibrational spectroscopic results indicate that reaction promotion is achieved by weakening the bonding between the N-containing products and the metal surface because of lateral interactions on the surface between 1-methylpyrrole and the reaction species, reducing the desorption energy of the products. It was found that the ring-opening product butylamine was a reaction poison over both surfaces, but this effect can be minimized by treating the catalyst surfaces with 1-methylpyrrole before reaction. The reaction rate was not enhanced with elevated temperatures, and SFG suggests desorption of pyrrole at elevated temperatures.

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Section: Surface Species During Reaction On Unpromoted Pt(111) and Rhmentioning

confidence: 99%

Pyrrole Hydrogenation over Rh(111) and Pt(111) Single-Crystal Surfaces and Hydrogenation Promotion Mediated by 1-Methylpyrrole: A Kinetic and Sum-Frequency Generation Vibrational Spectroscopy Study

Kliewer¹,

Bieri²,

Somorjai³

2008

J. Phys. Chem. C

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“…Assignments were made on the basis of correlations with vibrations assigned in related molecules. In general, the assignments of the vibrations involving the amino group of Bu t NH 2 follow those given for isopropylamine [2], nbutylamine [4], and the remaining vibrations follow the assignments given for t-butyl(tbutylimino)borane (CH 3 ) 3 CBNC(CH 3 ) 3 and di-t-butylethyne (CH 3 ) 3 CCCC(CH 3 ) 3 [10]. It is apparent from Figures 1 and 2 that the spectra of Bu t OH are very similar to those of Bu t NH 2 .…”

Section: Vibrational Spectral Assignments Of Bu T Oh and Bu T Nh 2 LImentioning

confidence: 60%

“…The band at 1320 cm -1 weak in both the Raman and IR spectra is assigned to the NH 2 twisting vibration while the other weak band at 1000 cm -1 is assigned to the symmetric C-N stretching. The remaining three bands are assigned to the CH 3 rocking and C-C symmetric stretching [2,4,10]. The two bands observed at 1240 and ca.…”

Section: Vibrational Spectral Assignments Of Bu T Oh and Bu T Nh 2 LImentioning

confidence: 99%

“…Vibrational spectra are, in general, sensitive to the local environment of a molecule, and information concerning the relative position of the molecule in quite a short time can be obtained from the spectra. Studies of the vibrational spectra of some organic amines such as cyclopentylamine [1], isopropylamine [2], n-propylamine [3], and n-butylamine [4,5], have been reported in the last few years. Many organic alcohols have also been extensively investigated.…”

Section: Introductionmentioning

confidence: 99%

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Vibrational spectra of t-butyl alcohol, t-butylamine and t-butyl alcohol + t-butylamine binary liquid mixtures

Kipkemboi

Kiprono

Sanga

2004

Bull. Chem. Soc. Eth.

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Raman and FT-IR absorption spectra of t-butyl alcohol and t-butylamine pure components have been recorded in the liquid state in the region of 400-4000 cm -1 . The data obtained have been used to propose complete vibrational assignments for each of the liquid component and the structural features are discussed. Additionally, the Raman and infrared spectra of the binary liquid mixtures for the t-butyl alcohol/t-butylamine system have also been recorded. The variations in frequency shifts, intensities and line widths are discussed with a view to understanding the origin of such variations.

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“…We further investigated the temperature dependence of this reaction ranging from 298-413 K over both surfaces, but the rate of formation of pyrrolidine was not enhanced with temperature, and at elevated temperatures reaction deactivation was observed. pyrrolidine, 36 and butylamine 37,38 in the spectral region between 2700 and 3600 cm -1 . that an intact aromatic ring is adsorbed on the surface.…”

Section: Sample Preparationmentioning

confidence: 99%

In-situ Studies of the Reactions of Bifunctional and Heterocyclic Molecules over Noble Metal Single Crystal and Nanoparticle Catalysts Studied with Kinetics and Sum-Frequency Generation Vibrational Spectroscopy

Kliewer¹

2009

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found that the ring-cracking product butylamine is a reaction poison over both surfaces studied.Furan hydrogenation was studied over Pt(111), Pt(100), 10 nm cubic platinum nanoparticles and 1 nm platinum nanoparticles. The product distribution was observed to be highly structure sensitive and the acquired SFG-VS spectra reflected this sensitivity.Pt(100) exhibited more ring-cracking to form butanol than Pt(111), while the nanoparticles yielded higher selectivities for the partially saturated ring dihydrofuran.Pyridine hydrogenation was investigated over Pt(111) and Pt(100). The α-pyridyl surface adsorption mode was observed with SFG-VS over both surfaces. 1,4-dihydropyridine was seen as a surface intermediate over Pt (100) but not Pt(111). Upon heating the surfaces to 350K, the adsorbed pyridine changes to a flat-lying adsorption mode. No evidence was found for the pyridinium cation.The hydrogenation of the α,β-unsaturated aldehydes acrolein, crotonaldehyde, and prenal were investigated over Pt(111) and Pt(100). The selectivity for the hydrogenation of the C=C bond was found to depend on the number of methyl groups added to the bond. The adsorption modes of the three aldehydes were determined. The hydrogenation of crotonaldehyde was found to be nearly structure insensitive as the TOF and selectivity were very close to the same over Pt(111) and Pt(100). SFG-VS indicated identical surface intermediates over the two crystal faces during crotonaldehyde hydrogenation.

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Conformational studies by Raman spectroscopy and statistical analysis of gauche interactions in n-butylamine

Cited by 36 publications

References 28 publications

Pyrrole Hydrogenation over Rh(111) and Pt(111) Single-Crystal Surfaces and Hydrogenation Promotion Mediated by 1-Methylpyrrole: A Kinetic and Sum-Frequency Generation Vibrational Spectroscopy Study

Pyrrole Hydrogenation over Rh(111) and Pt(111) Single-Crystal Surfaces and Hydrogenation Promotion Mediated by 1-Methylpyrrole: A Kinetic and Sum-Frequency Generation Vibrational Spectroscopy Study

<b>Vibrational spectra of <i>t</i>-butyl alcohol, <i>t</i>-butylamine and <i>t</i>-butyl alcohol + <i>t</i>-butylamine binary liquid mixtures</b>

In-situ Studies of the Reactions of Bifunctional and Heterocyclic Molecules over Noble Metal Single Crystal and Nanoparticle Catalysts Studied with Kinetics and Sum-Frequency Generation Vibrational Spectroscopy

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