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Hypersonic speed and dynamic isentropic compressibility in pyridazine
0-337(N) J. Chem. Thermodynamics 1989, 21, 895-896
Note Hypersonic pyridazine
speed and dynamic
isentropic
compressibility
in
SAIR HAGOPIAN and SCOTT L. WHITTENBURG of New
Depmtment 01’ Chemistry, University New Orleans. LA 70148. U.S.A. i Received
12 April
1989; in ,jnaI fbrm
15 May
Orleuns.
1989)
The hypersonic speed and dynamic isentropic compressibility of pure pyridazine (1,2-diazine) were measured from 262.6 to 363.4 K using Brillouin light scattering in the 5.8 to 7.5 GHz frequency region. The results are given in table 1. The details of the experimental arrangement and the numerical methods employed have been given.“’ The hypersonic speed u was calculated from the measured Brillouin splitting 1’ using M = ‘rev/q,
(1)
where q is the magnitude of the scattering wavevector, given by q =
(47cn/EJ sin (e/2),
(2)
where n is the refractive index, 1 is the wavelength of the incident light, and 8 is the scattering angle. The dynamic isentropic compressibility K~ was calculated using j$--= u- zp-‘,
TABLE
1. Brillouin
T K
GKz
262.6 265.7 269.2 272.7 278.5 280.3 282.8 286.0 290.6 295.9
7.51 7.37 7.35 7.29 7.27 7.17 7.11 7.08 6.99 6.97
(3)
frequencies Y, hypersonic speeds u, and isentropic compressibilities
-1 rn.“,1810 1770 1770 1750 1740 1720 1700 1690 1670 1660
0021-9614/89/080895+02
s Ci;ax’ 0.271 0.284 0.285 0.292 0.296 0.304 0.311 0.315 0.323 0.328 $02.00/O
T K 299.8 303.7 307.6 311.4 315.3 319.2 323.2 326.9 330.8 334.6
6.93 6.86 6.76 6.72 6.65 6.57 6.49 6.41 6.37 6.33
1650 1640 1610 1600 1580 1560 1540 1520 1510 1500
0.332 0.338 0.352 0.356 0.366 0.376 0.386 0.398 0.405 0.413
T K
GKz
338.6 342.5 345.9 350.2 354.1 358.0 362.7 363.4
6.32 6.25 6.12 6.02 6.03 5.90 5.83 5.82
K~,
of pyridazine
rn.uS-l GIF1480 1450 1440 1420 1420 1390 1370 1370
0.425 0.443 0.450 0.463 0.465 0.486 0.502 0.502
:i’, 1989 Academic Press Limited
’
896
NOTE
where p is the density. For our measurement 8 was 7r/2. Analysis of the results required the temperature dependenceof the density and refractive index; values were taken from the literature and extrapolated to the experimental temperatures.‘2’ The temperature dependence of the density is given by p/(g *cmm3)= -5.94 x 10P”(T/K)+ 1.282, and the temperature dependence of the index of refraction by n = 3.79 x lo-“(T/K)+ 1.4108.The calculated values for the hypersonic speed are accurate to a maximum error of 2 per cent. The measurementswere made as part of a study of hypersonic speed in nitrogen bases.“, 3, A dispersion in the hypersonic speed was not observed in 1,2-diazine. REFERENCES 1. Jain, V. K.; Whittenburg, S. L. J. Phys. Chem. 1988, 92, 2023. 2. Merck Index. 10th edition. Merck: Rahway, N. J. 1983. 3. Hagopian, S.; Whittenburg, S. L. to be published.
Note Hypersonic pyridazine
speed and dynamic
isentropic
compressibility
in
SAIR HAGOPIAN and SCOTT L. WHITTENBURG of New
Depmtment 01’ Chemistry, University New Orleans. LA 70148. U.S.A. i Received
12 April
1989; in ,jnaI fbrm
15 May
Orleuns.
1989)
The hypersonic speed and dynamic isentropic compressibility of pure pyridazine (1,2-diazine) were measured from 262.6 to 363.4 K using Brillouin light scattering in the 5.8 to 7.5 GHz frequency region. The results are given in table 1. The details of the experimental arrangement and the numerical methods employed have been given.“’ The hypersonic speed u was calculated from the measured Brillouin splitting 1’ using M = ‘rev/q,
(1)
where q is the magnitude of the scattering wavevector, given by q =
(47cn/EJ sin (e/2),
(2)
where n is the refractive index, 1 is the wavelength of the incident light, and 8 is the scattering angle. The dynamic isentropic compressibility K~ was calculated using j$--= u- zp-‘,
TABLE
1. Brillouin
T K
GKz
262.6 265.7 269.2 272.7 278.5 280.3 282.8 286.0 290.6 295.9
7.51 7.37 7.35 7.29 7.27 7.17 7.11 7.08 6.99 6.97
(3)
frequencies Y, hypersonic speeds u, and isentropic compressibilities
-1 rn.“,1810 1770 1770 1750 1740 1720 1700 1690 1670 1660
0021-9614/89/080895+02
s Ci;ax’ 0.271 0.284 0.285 0.292 0.296 0.304 0.311 0.315 0.323 0.328 $02.00/O
T K 299.8 303.7 307.6 311.4 315.3 319.2 323.2 326.9 330.8 334.6
6.93 6.86 6.76 6.72 6.65 6.57 6.49 6.41 6.37 6.33
1650 1640 1610 1600 1580 1560 1540 1520 1510 1500
0.332 0.338 0.352 0.356 0.366 0.376 0.386 0.398 0.405 0.413
T K
GKz
338.6 342.5 345.9 350.2 354.1 358.0 362.7 363.4
6.32 6.25 6.12 6.02 6.03 5.90 5.83 5.82
K~,
of pyridazine
rn.uS-l GIF1480 1450 1440 1420 1420 1390 1370 1370
0.425 0.443 0.450 0.463 0.465 0.486 0.502 0.502
:i’, 1989 Academic Press Limited
’
896
NOTE
where p is the density. For our measurement 8 was 7r/2. Analysis of the results required the temperature dependenceof the density and refractive index; values were taken from the literature and extrapolated to the experimental temperatures.‘2’ The temperature dependence of the density is given by p/(g *cmm3)= -5.94 x 10P”(T/K)+ 1.282, and the temperature dependence of the index of refraction by n = 3.79 x lo-“(T/K)+ 1.4108.The calculated values for the hypersonic speed are accurate to a maximum error of 2 per cent. The measurementswere made as part of a study of hypersonic speed in nitrogen bases.“, 3, A dispersion in the hypersonic speed was not observed in 1,2-diazine. REFERENCES 1. Jain, V. K.; Whittenburg, S. L. J. Phys. Chem. 1988, 92, 2023. 2. Merck Index. 10th edition. Merck: Rahway, N. J. 1983. 3. Hagopian, S.; Whittenburg, S. L. to be published.