Microwave Absorption and Molecular Structure in Liquids. XLIII. Dielectric Relaxation and Intramolecular Rotation in Ten Aromatic Amines<sup>1,2</sup>

Grubb, Eugene L.; Smyth, Charles P.

doi:10.1021/ja01485a002

Cited by 23 publications

(8 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In general, when the observed relaxation time is shorter than that anticipated, it suggests a contribution from an additional relaxation process(es). This appears the case for aniline in benzene (2) at 20 "C since the observed relaxation time is 4.3 x 10-" s which is to be compared with a molecular relaxation time of 7.5 x 10-l2 s for chlorobenzene in cyclohexane (3) at 25 "C.…”

mentioning

confidence: 75%

“…[ I ] and [2]. The terins E',,~,, and E",,,,, Dipole moments were obtained from the Debye calculated using the T,, T,, and C, values gi\ en equation for dilute solutions by computer analysis are listed in Table 11, together with the mean relaxation time and electric [3] …”

Section: E mentioning

confidence: 99%

“…For Debye beha1 ior, the plot is a straight line from the equation of the 70.01 GHz results it was not possible to determine E, with sufficient accuracy to deduce r1 and r 2 from eq. [ 2 ] . Estimates of the two relaxation times were obtained from E' vs. ~" o plots.…”

Section: E mentioning

confidence: 99%

See 2 more Smart Citations

Dielectric studies. Part XXIII. Relaxation data and apparent dipole moments of aniline and some disubstituted aromatic amines

Tucker¹,

Walker²

1969

Can. J. Chem.

View full text Add to dashboard Cite

Dielectric studies have been carried out at microwave frequencies on dilute solutions of aniline, pchloro-, p-bromo-, and m-chloro-anilines, and o-, 171-, and p-toluidines at 25 'C in cyclohexane and pxylene. The static dielectric constant has also been nleasured at 2 MHz. In addition o-and m-toluidines have beenrneasured at 50 ' C andp-toluidine at 15,35, and 50 ^C.The dielectric results, particularly those at 70.01 GHz, establish that there is more than one relaxation process present and the data have been analyzed on a two relaxation time model, the longer of \\hich T , , is identified as molecular relaxation. The cause of the lower electric dipole moments found from this method as opposed to the non-dielectric absorption methods is discussed. It follows that there is either an additional higher frequency dispersion or (and) a high atomic polarization for aniline and o-, rn-, and p-toluidines. Work at still higher frequencies is required to study this further and to establish more precise values of 72.Canadian Journal of Chemistry, 47, 681 (1969) When two polar solutes of similar size and shape are independently examined in a particular non-polar solvent and the solute is present at low concentration, then, providing there is no appreciable molecular interaction and the solute molecules undergo no intramolecular motion (such as group re-orientation), similar observed relaxation times are to be expected. The observed relaxation time would then be the molecular relaxation time. Such considerations were embodied i11 the work of Fischer (1) and used to identify the lack of rigidity in certain molecules. In general, when the observed relaxation time is shorter than that anticipated, it suggests a contribution from an additional relaxation process(es). This appears the case for aniline in benzene (2) at 20 "C since the observed relaxation time is 4.3 x 10-" s which is to be compared with a molecular relaxation time of 7.5 x 10-l2 s for chlorobenzene in cyclohexane (3) at 25 "C.This present work aimed to examine whether such a shortening of the relaxation time of primary aromatic amines in non-polar solvents was a general phenomenon. Further, it seemed likely that measurements at 70.01 GHz would help to establish any contribution from a short relaxation time more precisely. It was considered worthwhile to carry out measurements in the two solvents in order to assess whether the dipole moments and relaxation times were highly dependent on specific solvent effects. ExperimentalThe apparatus and procedure for determining the dielectric constant and loss have been described previously (4). MaterialsThe .liquid anlines were all distilled fro111 a spinning band column of 35 theoretical plates and then dried. The observed boiling points were compared uith literat~~re values, and the compounds were s l i o~n to have no detectable amounts of impurities by infrared and gas chroniatographic techniques.The solids were recrystallized from appropriate solvents and dried until their melting points agreed \\ith those in the lite...

show abstract

mentioning

confidence: 75%

Section: E mentioning

confidence: 99%

See 1 more Smart Citation

Dielectric studies. Part XXIII. Relaxation data and apparent dipole moments of aniline and some disubstituted aromatic amines

Tucker¹,

Walker²

1969

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

“…The benzene molecule is in many respects structurally similar to the aniline molecule and one would therefore expect that particularly the angular reorientation of the aniline molecule in benzene solution should be similar in nature to the angular reorientation of the molecule in liquid aniline. The dielectric relaxation time of the aniline molecule in dilute benzene solution has been measured by several workers (9,10). The most recent determination of this quantity by Tucker and Walker (10) in dilute cyclohexane and p-xylene solution yields a value of 8.5 x 10-l2 and 8.1 x lo-'' s, respectively for the reorientational relaxation time of the molecule and a value of 2.1 x lo-'' -3.3 x lo-'' s for a second relaxation time presumably associated with some inter-molecular motion taking place withing the molecule.…”

Section: Resultsmentioning

confidence: 99%

Proton spin – lattice relaxation time of aniline-d₂ in deuterated benzene and deuterated aniline solution

Bock¹,

Czubryt²,

Tomchuk³

1970

Can. J. Chem.

View full text Add to dashboard Cite

The proton spin -lattice relaxation time of aniline-d2 in deuterated aniline solution was determined as a function of concentration and temperature over the temperature interval 26C-360 "K using a pulsed nuclear magnetic resonance technique. In addition the proton spin -lattice relaxation time of aniline-d2 in deuterated benzene solution at 20 "C was also determined. It was found that the activation energies of the intra-and inter-molecular relaxation rates were of similar magnitude, viz. 4.5 and 4.4 kcal/mole,

show abstract

“…Früher wurden parallel zu Anilin meist auch Diphenylamin und Triphenylamin [4][5][6][7][8][9][10][11] untersucht. Dabei erhielt man allgemein wichtige Hinweise für ein molekülinternes Umklappen des Dipolmoments von Aminen, denn bei ihnen fand man ebenfalls, daß sich eine Momentkomponente sehr schnell umorientiert.…”

unclassified

Molekülinterne Dipolorientierung und dielektrische Absorption in verdünnter Lösung bei Mikro- und Submillimeterwellen. IL Sekundäre und tertiäre Amine / Intramolecular Dipole Reorientation and Dielectric Loss of Microwaves and Submillimetrewaves in Diluted Solution II. Secondary and Tertiary Amines

Klages

Wieczorek

1982

Zeitschrift Für Naturforschung A

View full text Add to dashboard Cite

Supplementary to a preceding investigation on primary amines, the dielectric loss increments of three aromatic dimethylamino compounds, diphenylamine, N-methyldiphenylamine and triphenylamine, and of dicyclohexylamine have been measured in very diluted solutions at 20 °C. The loss data resulting from 0.1 up to 250 cm -1 are now covering the complete absorption region due to reorientation of the permanent molecular dipole, especially that part based on inversion. To resolve this part, the absorption curves are analysed in terms of three areas using the same method as done for primary amines. By this the dipole components assigned to the special reorientation processes may be discerned and discussed. So the dipole component of the dimethylamino group which reorientates by intramolecular motion is smaller than that of the amino group. The occurrence of an inversion process is demonstrated, but the molecular dipole component governing it also may reorient more slowly as the result of a hindered inversion. The additional reorientation of a mesomeric moment by twisting of the phenyl groups is suggested in triphenylamine and in the diphenyl compounds. The aliphatic dicyclohexylamine only shows a Poley absorption area, increased perhaps by intramolecular libration. Orientierung der innerhalb des Moleküls beweglichen Momentkomponente gehört, aber bei Wellenzahlen liegt, die um eine Dekade kleiner sind. Es wird daher solchen polaren Molekülen in der gemessenen Probe zugeschrieben, bei denen die Inversion kurzzeitig behindert ist. Das Absorptionsgebiet der molekülfesten Momentkomponente liegt bei noch längeren Wellen. In einer vorangehendenFrüher wurden parallel zu Anilin meist auch Diphenylamin und Triphenylamin [4-11] untersucht. Dabei erhielt man allgemein wichtige Hinweise für ein molekülinternes Umklappen des Dipolmoments von Aminen, denn bei ihnen fand man ebenfalls, daß sich eine Momentkomponente sehr schnell umorientiert. Ihre Größe und die zugehörige Zeitkonstante waren aber bisher nur durch Extrapolation zu ermitteln. Es bietet sich daher an, auch bei diesen und anderen sekundären und tertiären Aminen die Absorption von Submillimeterwellen zu messen, um die Kenntnisse über alle Orientierungsvorgänge ihrer permanenten Dipole und deren charakteristische Parameter zu vervollständigen. Auswertung der MeßdatenEs werden die gleichen Apparaturen für Mikrowellen und das ferne Infrarotgebiet (FIR) wie 0340-4811 / 82 / 0203-0134 $ 01.3 0/0. -Please order a reprint rather than making your own copy.

show abstract

Microwave Absorption and Molecular Structure in Liquids. XLIII. Dielectric Relaxation and Intramolecular Rotation in Ten Aromatic Amines^1,2

Cited by 23 publications

References 0 publications

Dielectric studies. Part XXIII. Relaxation data and apparent dipole moments of aniline and some disubstituted aromatic amines

Dielectric studies. Part XXIII. Relaxation data and apparent dipole moments of aniline and some disubstituted aromatic amines

Proton spin – lattice relaxation time of aniline-d₂ in deuterated benzene and deuterated aniline solution

Contact Info

Product

Resources

About

Microwave Absorption and Molecular Structure in Liquids. XLIII. Dielectric Relaxation and Intramolecular Rotation in Ten Aromatic Amines1,2

Cited by 23 publications

References 0 publications

Dielectric studies. Part XXIII. Relaxation data and apparent dipole moments of aniline and some disubstituted aromatic amines

Dielectric studies. Part XXIII. Relaxation data and apparent dipole moments of aniline and some disubstituted aromatic amines

Proton spin – lattice relaxation time of aniline-d2 in deuterated benzene and deuterated aniline solution

Contact Info

Product

Resources

About

Microwave Absorption and Molecular Structure in Liquids. XLIII. Dielectric Relaxation and Intramolecular Rotation in Ten Aromatic Amines^1,2

Proton spin – lattice relaxation time of aniline-d₂ in deuterated benzene and deuterated aniline solution