- Email: [email protected]
Ideal gas state thermodynamic functions for monohalogenated cyclo-alkanes
63 Thermochimica Acfa, 10 (1974) 63-72 Q Ehcvier ScientificPublishingCornParry,Amsterdam- Printed in Belgium
IDEAL GAS STATE THERMODYNAMIC FUNCTIONS FOR MONOHALOGENATED CYCLO-ALKANES M. J. KELLY* AND J. LIELMEZS Chemical Engineering Department,
7%~ Unizersiry of British Cohmzbia,
Vancorrser 8, S’.C. (Canado)
(Received 6 May 1974)
The thermodynamic functions, Ci, S’, -(F”-IQ/T and (W-&)/T, have been calculated in the ideal gas state at I atm for the following monohalogenated cycioalkanes: bromocyclopropane, bromocyclobutane, chlorocyclobutane, fluorocyclobutane, bromocyciopentane. The effect of pseudorotation of the cyclobutanes and bromocyclopentane on the thermodynamic function values was considered to be negligible. INTRODUCnON
The published spectroscopic and structural data for several haiogenated monocycIoalkanes l--I ‘, have made it possibIe to calculate the thermodynamic functionsheat capacity, enthalpy, entropy, and free energy for bromocyclopropane, bromocyclobutane, chlorocyclobutane, fluorocyclobutane and broaocyclopentane in the ideal gas state at a pressure of 1 atm. The functions for each given compound were caIcuIated by means of the well-known statistical mechanicai methodsThe results presented in Table 1 were fitted’2 to eqn (1) h=a+bT+cT’
(1)
where A is the thermodynamic function at temperature T (IQ_ The corstants a, b and c (eqn 1) were obtained using Ieast squares curve fitting methods’ ’ and are found in TabIe 2 and Figs. 1-4. TabIe 2 also lists a, b and c values for iodocyclobutane. These a, b and c values of iodocyclobutane were estimated from Figs. 1-4 extrapolating the corresponding a, b and c vaiues of bromo-, chloro- and fluorocycIobutanes_ Table 3 presents the values of the molecular parameters used in thermodynamic function calculations_
‘Present address:Prince George Pulp & Pancr, Prince George, B.C., Canada.
64 DISCZSSIOX
Bronrocylopropane The thermodynamic functions (Table I) for bromocyclopropane were calculated using the fundamental vibration frequency assignments made by Rothschild’ and the structuraI data of Lam and DaiIey’. Habc_rclobrrranes The structural configurations and the vibrational spectra of halocyclobutanes have been studied by severa investigators 3-g _ In this work to calculate the thermo-l-ABLE
HEAT
1 CAPACITY,
EhTROPY. Temperarure Kl
FREE ENERGY Bromocyclopropme
Heat capacity, C, (cd mol- x K- *) 273.15 298.15 350.00 400.00
550.00 600.00 650.00 700.00 750.00 500.00 s50.00 Voo.00 450).00 1ooo.00
24.69 26.77 28.60 30.22 31.65 3292 34.05 35.07 35.98 36.81 37.56 3S.M
273.15 298.15 35o.oQ 4OOao 450.00 500.00 550.00 600_00 650.00 700.00 750.00 SOO.00 850.00 Voo.00 950.00 1000.00
69.73 71.30 74.50 77.53 80.49 83.38 86.18 88.58 91.49 94.01 96.43 98.77 101.00 103.20 fO5.30 iO7.30
450.00 ,w.oo
Entropy, S; (ea.)
15s1 16.91 19.77 3135 --
AND
Bromocyclebutane
18.57 20-30 23.85 27.09 30.04 32.70 35.09 37.24 39.17 40-93 42-M 44.01 45.37 46.61 47.77 4s.s-s 74.53 76.38 80.18 83.80 87.36 90.84 91.22 97.52 100.70 103.80 106.50 109.70 112.50 115.20 117.Vo 120.40
ENTHALPY ChioroCJdlbutane
FUNGI-ION Fluorocycrobutane
16.42 18.13 21.70 25.03 28_12 30.94
BromoCJdOpenfane
17.57 19.29 22.85 26.1; 29.15 31.88 34.34 36.55 38.55 40.37 42-03 43.55 44.95 46.24 47.43 48.5
35.75 37.85 39.74 41.46 43.03 44.48 45.81 47.04 45.17
24.27 26.37 30.69 34.63 38.26 41.56 44.55 47.25 49.71 51.95 54.00 55.89 57.63 59.23 60.72 62.09
69.12 70.88 74.52 78.00 81.45 84.84 88.16 91.39 94.12 97.57 I(io.50 103.4Q X06.20 108.90 III.50 114.00
68.75 70.40 73.85 77.19 80.52 83.80 87.03 Vo_I9 93.27 96.27 99.18 lOLO 104.80 107.40 11O.OQ 112.60
s4.51 86.87 vi.71 96.29 100.80 105.10 109.40 113.50 117.60 121.40 I2520 128.90 132.40 135.80 139.20 142-40
33.48
65 TABLE
1 (conrinucd) Temperature BromoCJdOWI propane
Bromoc)-ciobutane
Chlorocycleburane
FiuorocJd?burane
Bromoc+?penlane
Free energy function, -(F= - H;)jT (cd mol-1 K-l)
273.15 298.15 350.00 400.00 450.00 500.00 SSG.00 600.00 650.00 700.00 750.00 800.00 .?50.00 900.00 950.00 1OGO.00
58-59 59.59 61.56 63.37 65.11 66.79 68.43 70.32 71.57 73.08 74.56 76.00 77-4 I 78.75 so.12 81.43
61.76 62.9 1 65.18 67.25 69.32 71.30 73.23 75.11 76.96 78.77 so.54 82.27 83.9i 85.63 87.25 88.85
56.95 58.05 60.22 62.22 64.17 66.07 67.92 69.75 71.53 73.28 75.00 76.69 78.34 79.96 81.55 83.12
57.23 5827 60.32 6-?-V _ __ 64-07 65.88 67.66 69.40 71.12 72.81 74.47 16.10 77.71 79.29 80.24 82.36
68.56 '70.00 72.86 75.50 78.06 80.55 82.98 85.36 87.68 89.96 92-18 94.36 96.50 9ss9 100.60 102.60
Enthalpy function, (Ho- H&‘T
273.15 298.15 350.00 400.00 450.00 500.00 55O.Cil 600.00 650.00 700.00 750.00 800.00 850.00 900.00 950.00 1000.00
Il.14 11.71 12.94 14.16 15.38 16.59 17.75 18.86 19.92 20.93 21.87 22.77 23.61 24.42 25.18 2S.90
12-57 13.47 IS.00 16.52 IS.cH 19.54 20.99 22.41 23.75 25.03 26.25 27.42 28.53 29.59 30.63 31.58
12-17 12.83 14.30 15.78 17.28 18.77 20.24 21.64 22.59 24.29 25.53 26.7 ! 27.84 28.92 29.95 30.93
1 I.52 12.13 13.53 14.97 16.45 17.92 19.37 20.79 22.15 23.46 24.71 25.92 2'7.06 28.15 29.20 39.21
15.95 16.87 18.85 20.T9 22.71 24.60 26.43 28.19 29.88 31.49 33.04 34.52 35.92 37.26 33.54 39-77
dynamic properties for bromo-, chloro- and Auorocyclobutane (Table 1) we used the vibrational assignments of Durig et al.‘. The atomic coordinates for chloroqclobutane with the halogen in the equatorial position have already been caIcuIated by Kim and Gwinn4. However, they did not observe the halogen (X = Cl) in the axial position_ On the other hand, Kim and Gwinn’ indicated that the structure for fluorocyclobutane is similar to that for chlorobutane; and so they recommended a bond length of 1.37 j, for the C-F bond. Additional to this. in this work we assume that such is the case also for bromocyclobutane (Fig. 1) and we have adopted3*9 a bond Iength of I.939 A for the C-Br bond fo cakulate the atomic coordinates of bromine. Since Kim and Gwinns did not observe the axial position of the halogen atom and since the potential barrier to pseudorotation appears to be hi_eh4, only the classi-
66 cal thermodynamic function vahres for the isomer with the halogen (X = Br, Cl, F) in the equatorial4 position have been caiculated (Table 1).
Fig. I _ Structure of bromocyclobutanc.
The variation of the coeffkients a, b and c describing eqn (1) with the atomic weight of the substituent halogen atom (X = Br, Cl, F), is shown in Figs. 2-5 for each of the calculated thermod_ynamic functions. Since the obtained curves (Figs. 2-5) show smooth monotonic behavior, it is possibIe to extend these curves and by extrapolation to estimate the a, b, and c values for the iodocyclobutane (Table 2) However, for none of the Listed compounds (TabIes 1 and 2) we have supporting experimental evidence.
e 40
60
80
I
m
PO
FTs 2 Variation of the heat capacity coeEcients (TabIe 2) with the atomic weight of substituent atom.
se.4
_____------a
Fig. 3. Variation of the fire energy function coetlicients Cable substituent atom.
2) with the atomic u-eight of the
4-
3.
i-
_
__“3----,
l_
Fig. 4.
Variation of the entropy cocfiicients (Table 2j-with the atomic weight of the substituent atom_
68
4
,
1,
r---=--
_
____eL---4
I0
F
0
I
t
P406083kxYm
Atcmic Fig
m&ht
5- Variation of the CnthaIpyfunctionco&Gents Cable 2) with the atomic weight of substituent
atom-
Fig. 6. Strtz~
of bromocydopmtane
used to calrlatc
rk
COdOl?lYff.
with possx%Ie confo-
(a) Bromocyclopentane
st~cturc
momentof inertiaproduct; (b) Possible axial conformer; (c) Possible equatorial
69 TABLE
2
CALCULATED
CONSTANTS
0, b AND c IN EQN (1)
a
BromocycIopro_me co S”
bx
102
cx 10s
Stand&d erroP
-1-7891 50.8437 47.8081 3.0357
735 7.37 4.22 3.15
-33.386 - 1.721 -0.8661 - 0.8550
0.2266 0.0249 0.050I 0.0686
-2-7016 522396 49.3369 39026
8.93 8.63 4.82 3.80
-3.817 - !.806 - 0.8789 - 0.9274
0.2465 0.0370 O-0462 0.0799
- 4.102 47.8924 45.1685 27239
9.06 8.16 4.56 3.60
-
3.832 I.534 0.7680 0.7658
0.2235 0.1055 O-0425 0.1257
-(F’-H;);T (H’-H;)jT
- 5.7489 48.2992 46.145? 2.1533
9.22 7.79 4.27 3.53
-3.86 - 1.358 - 0.6492 -0_7091
0.1967 0.0858 0.0372 0.1227
Iodoqclobutane (estimated) C” SZ -(F”-H;)JT (Ho-H;)IT
- 1.93 59.0 56.5 3.00
8.85 8.80 4.83 4.00
- 3.75
-0.175
-
-4.521 -2.300 -1.099 - I.201
0.2570 0.0265 0.0572 0.0766
-(Fe--6)/T (Ho-H,O)!T
Bromocyclobctanc co S’ -(I==-H&T (Ho- H;))rT
Chlorocyclobutane cg, S’ -(F=- H;)/T (HO- H;),fT
Ruorocyclobutane c, S’
BromocycIopentanc G S” -(F’-H&fT (Ho- H;))lT
- 1.7571 56.4023 52.9403 3-4621
10.86 IO_90 6.06 4.84
a standard error of V is the numberS, where S = of observations ; m is the number of independent v&ables: and Y, is the ith extrapolatedvalue of Y (cqn. 1).
-1.90 - 0.905
m-Isuchthatnisthenumber Y, is the ith calculated value of Y Uable
1) ;
Bromocyciopentane The thermodynamic functions (Table 1) for bromocyclopentane were calculated using the fundamental frequencies assigned by Durig et al. lo- The belief advanced by Durig et al. lo that the chloro- and bromocy~lopentane rings may not undergo pseudo rotation (form conformers) is indirectIy supported by VoveIie et al.’ 1 through their observations that the position of the bromine atom (axial or equatorial, Fig. 6) does not affect the fundamental frequencies. These considerations have permitted to calculate the thermodynamic functions for bromocyciopentane as a planar ring mole-
3015 1423 1200 1OSl 887 760 309
2957 1264 1165 1030 862 54s 273
kcqrlcncica
‘1
3020b 2962 1451 1092 808 633 2992 1227 1025 896
[V, cm’ 3005 2868 1262 486 78s 302 2977 1181 963 824
ihmocychbumna
’ 135.012
a=1
h * 8,356 IN = 51,501 IC = 56,377
3015” 2923 145s 1103 84X 530 2989 1266 1123 910
1
90.544
a=
f” = 33,439 1~ = 38,349
2967 1400 1207 851 717 IS9 1430 1172 940 286
G - 8,320
3005 2854 1288 1024 781 365 2979 1242 971 815
Clhrncyclobutnne
~~ONOCYCLOALKANES
’ All frcqucncics from ref. 1, b All froquoncics from ref. 8. o All frequcncics, oxccpt I50 cm’ this work,
120.97
Molecular Weight
UP1
Molecular shop0 factor, o
IA = 34.304 Ill p 5.105 IC - 32,695
2977 1459 1197 1015 699 143 1440 1159 938 247
PARAMETERS 01: IIAL~czNAI’ED
Principal momcnts” of incttia, g cnaax 10Jp
3078~ 1448 1238 1089 927 810 493
~undanwHn1
ihtttocyclopropmra
MoLEcUI.AR
TABLE 3
2992 2950 1361 1098 7R3 4.56 2966 1221 1057 835
2912 1472 1242 1079 750 166 1441 1161 921 371 2994@ 2875 I449 1219 1003 2Hl5 1403 1134 1003 742 231 742 452
2924 1473 I208 1178 2924 1477 1237 1028 803 305 8R6 51s 15od
149.02
f, a 15,661 I,, = 63.129 r, = 71.473
2976 2852 1315 1209 2976 2852 1282 I066 935 584 903 716 289
10, d Estlmnlcd, this work, see Fig* 7, o Calculated,
74,094
J,, = 19,887 I,, = 24,878 k =I 8,241
I, from rcf’,
3006b 2861 1453 1140 959 599 2988 1263 IO49 899
71 cule3 existing structurally in state as shown by Fig. 6a. This point is strengthened through the observation that JO% error in the I~ABc-pL_~ value would yield an inaccuracy for entropy and free energy function values of ~aI
Fig. 7. Estimztion
of the missing fundamental
ring puckering
frequency
for bromowclopcntaue.
ACCURACY
Since there was no available experimental evidence, it was not possible to compare the caknlated thermodynamic function values with the experimental data_ However, indirectly a measure of the accuracy of the presented thermodynamic function values (Table 1) may be obtained, as the structural and spectroscopic data used (Table 3) are highly accurate and none of the Wed compounds may undergo pseudo-rotation- In view of this, it is expected that the cakulated classical thermodynamic function values wiIl be within the possibie measurement error range.
The financial assistance of the National Research Council of Canada is gratefully acknowkdged. REFERENCES I W. G. Rotschild, 1. Chem. Phys., 44 (666) 3875. 2 F. M. XC.Lam and B. P. Dailey, J. Chcrn- P&s., 49 (1968) 1588_ 3 Y. Yukawa (Ed.), Handhok of Orgatzic StructzwaI Ana&sis, W_ k &njamin,
NCW
York. 1965.
72 4 H. Kim and W. D. Gwinn. f. Chem. Phys., 44 (1966) 865. 5 3. R. Durig and 1. N. WiJIis, J. Chem. Phys.. 52 (1970) 6108. 6 W. G. RotschiJd. J. Chem. Phys... 45 (1966) 3599. 7 W_ G. RotschiJd, 3. Chem. Phys., 44 (1966) 1712. 8 J. R. D&g, J. N. Willis and W. H. Green, J. Chem. Phys.., 54 (1971) 1547. 9 W. G. RotschiId and B. P. Dailey, J. Chern. Pkys., 36 (1962) 2931. JO J. R. Durig, 3. .M. Karrikcr and D. W. Wcrtz, J. Mur. Specrrosc., 31 (1969) 237. 1 I F. VoveIk A. Le Roy and S. Idiot, f. Mol. Srwcr.. I I (1972) 53. 12 University
of British CoIumbh
Computing
Centre,
“TRIP”
program,
1973.
IDEAL GAS STATE THERMODYNAMIC FUNCTIONS FOR MONOHALOGENATED CYCLO-ALKANES M. J. KELLY* AND J. LIELMEZS Chemical Engineering Department,
7%~ Unizersiry of British Cohmzbia,
Vancorrser 8, S’.C. (Canado)
(Received 6 May 1974)
The thermodynamic functions, Ci, S’, -(F”-IQ/T and (W-&)/T, have been calculated in the ideal gas state at I atm for the following monohalogenated cycioalkanes: bromocyclopropane, bromocyclobutane, chlorocyclobutane, fluorocyclobutane, bromocyciopentane. The effect of pseudorotation of the cyclobutanes and bromocyclopentane on the thermodynamic function values was considered to be negligible. INTRODUCnON
The published spectroscopic and structural data for several haiogenated monocycIoalkanes l--I ‘, have made it possibIe to calculate the thermodynamic functionsheat capacity, enthalpy, entropy, and free energy for bromocyclopropane, bromocyclobutane, chlorocyclobutane, fluorocyclobutane and broaocyclopentane in the ideal gas state at a pressure of 1 atm. The functions for each given compound were caIcuIated by means of the well-known statistical mechanicai methodsThe results presented in Table 1 were fitted’2 to eqn (1) h=a+bT+cT’
(1)
where A is the thermodynamic function at temperature T (IQ_ The corstants a, b and c (eqn 1) were obtained using Ieast squares curve fitting methods’ ’ and are found in TabIe 2 and Figs. 1-4. TabIe 2 also lists a, b and c values for iodocyclobutane. These a, b and c values of iodocyclobutane were estimated from Figs. 1-4 extrapolating the corresponding a, b and c vaiues of bromo-, chloro- and fluorocycIobutanes_ Table 3 presents the values of the molecular parameters used in thermodynamic function calculations_
‘Present address:Prince George Pulp & Pancr, Prince George, B.C., Canada.
64 DISCZSSIOX
Bronrocylopropane The thermodynamic functions (Table I) for bromocyclopropane were calculated using the fundamental vibration frequency assignments made by Rothschild’ and the structuraI data of Lam and DaiIey’. Habc_rclobrrranes The structural configurations and the vibrational spectra of halocyclobutanes have been studied by severa investigators 3-g _ In this work to calculate the thermo-l-ABLE
HEAT
1 CAPACITY,
EhTROPY. Temperarure Kl
FREE ENERGY Bromocyclopropme
Heat capacity, C, (cd mol- x K- *) 273.15 298.15 350.00 400.00
550.00 600.00 650.00 700.00 750.00 500.00 s50.00 Voo.00 450).00 1ooo.00
24.69 26.77 28.60 30.22 31.65 3292 34.05 35.07 35.98 36.81 37.56 3S.M
273.15 298.15 35o.oQ 4OOao 450.00 500.00 550.00 600_00 650.00 700.00 750.00 SOO.00 850.00 Voo.00 950.00 1000.00
69.73 71.30 74.50 77.53 80.49 83.38 86.18 88.58 91.49 94.01 96.43 98.77 101.00 103.20 fO5.30 iO7.30
450.00 ,w.oo
Entropy, S; (ea.)
15s1 16.91 19.77 3135 --
AND
Bromocyclebutane
18.57 20-30 23.85 27.09 30.04 32.70 35.09 37.24 39.17 40-93 42-M 44.01 45.37 46.61 47.77 4s.s-s 74.53 76.38 80.18 83.80 87.36 90.84 91.22 97.52 100.70 103.80 106.50 109.70 112.50 115.20 117.Vo 120.40
ENTHALPY ChioroCJdlbutane
FUNGI-ION Fluorocycrobutane
16.42 18.13 21.70 25.03 28_12 30.94
BromoCJdOpenfane
17.57 19.29 22.85 26.1; 29.15 31.88 34.34 36.55 38.55 40.37 42-03 43.55 44.95 46.24 47.43 48.5
35.75 37.85 39.74 41.46 43.03 44.48 45.81 47.04 45.17
24.27 26.37 30.69 34.63 38.26 41.56 44.55 47.25 49.71 51.95 54.00 55.89 57.63 59.23 60.72 62.09
69.12 70.88 74.52 78.00 81.45 84.84 88.16 91.39 94.12 97.57 I(io.50 103.4Q X06.20 108.90 III.50 114.00
68.75 70.40 73.85 77.19 80.52 83.80 87.03 Vo_I9 93.27 96.27 99.18 lOLO 104.80 107.40 11O.OQ 112.60
s4.51 86.87 vi.71 96.29 100.80 105.10 109.40 113.50 117.60 121.40 I2520 128.90 132.40 135.80 139.20 142-40
33.48
65 TABLE
1 (conrinucd) Temperature BromoCJdOWI propane
Bromoc)-ciobutane
Chlorocycleburane
FiuorocJd?burane
Bromoc+?penlane
Free energy function, -(F= - H;)jT (cd mol-1 K-l)
273.15 298.15 350.00 400.00 450.00 500.00 SSG.00 600.00 650.00 700.00 750.00 800.00 .?50.00 900.00 950.00 1OGO.00
58-59 59.59 61.56 63.37 65.11 66.79 68.43 70.32 71.57 73.08 74.56 76.00 77-4 I 78.75 so.12 81.43
61.76 62.9 1 65.18 67.25 69.32 71.30 73.23 75.11 76.96 78.77 so.54 82.27 83.9i 85.63 87.25 88.85
56.95 58.05 60.22 62.22 64.17 66.07 67.92 69.75 71.53 73.28 75.00 76.69 78.34 79.96 81.55 83.12
57.23 5827 60.32 6-?-V _ __ 64-07 65.88 67.66 69.40 71.12 72.81 74.47 16.10 77.71 79.29 80.24 82.36
68.56 '70.00 72.86 75.50 78.06 80.55 82.98 85.36 87.68 89.96 92-18 94.36 96.50 9ss9 100.60 102.60
Enthalpy function, (Ho- H&‘T
273.15 298.15 350.00 400.00 450.00 500.00 55O.Cil 600.00 650.00 700.00 750.00 800.00 850.00 900.00 950.00 1000.00
Il.14 11.71 12.94 14.16 15.38 16.59 17.75 18.86 19.92 20.93 21.87 22.77 23.61 24.42 25.18 2S.90
12-57 13.47 IS.00 16.52 IS.cH 19.54 20.99 22.41 23.75 25.03 26.25 27.42 28.53 29.59 30.63 31.58
12-17 12.83 14.30 15.78 17.28 18.77 20.24 21.64 22.59 24.29 25.53 26.7 ! 27.84 28.92 29.95 30.93
1 I.52 12.13 13.53 14.97 16.45 17.92 19.37 20.79 22.15 23.46 24.71 25.92 2'7.06 28.15 29.20 39.21
15.95 16.87 18.85 20.T9 22.71 24.60 26.43 28.19 29.88 31.49 33.04 34.52 35.92 37.26 33.54 39-77
dynamic properties for bromo-, chloro- and Auorocyclobutane (Table 1) we used the vibrational assignments of Durig et al.‘. The atomic coordinates for chloroqclobutane with the halogen in the equatorial position have already been caIcuIated by Kim and Gwinn4. However, they did not observe the halogen (X = Cl) in the axial position_ On the other hand, Kim and Gwinn’ indicated that the structure for fluorocyclobutane is similar to that for chlorobutane; and so they recommended a bond length of 1.37 j, for the C-F bond. Additional to this. in this work we assume that such is the case also for bromocyclobutane (Fig. 1) and we have adopted3*9 a bond Iength of I.939 A for the C-Br bond fo cakulate the atomic coordinates of bromine. Since Kim and Gwinns did not observe the axial position of the halogen atom and since the potential barrier to pseudorotation appears to be hi_eh4, only the classi-
66 cal thermodynamic function vahres for the isomer with the halogen (X = Br, Cl, F) in the equatorial4 position have been caiculated (Table 1).
Fig. I _ Structure of bromocyclobutanc.
The variation of the coeffkients a, b and c describing eqn (1) with the atomic weight of the substituent halogen atom (X = Br, Cl, F), is shown in Figs. 2-5 for each of the calculated thermod_ynamic functions. Since the obtained curves (Figs. 2-5) show smooth monotonic behavior, it is possibIe to extend these curves and by extrapolation to estimate the a, b, and c values for the iodocyclobutane (Table 2) However, for none of the Listed compounds (TabIes 1 and 2) we have supporting experimental evidence.
e 40
60
80
I
m
PO
FTs 2 Variation of the heat capacity coeEcients (TabIe 2) with the atomic weight of substituent atom.
se.4
_____------a
Fig. 3. Variation of the fire energy function coetlicients Cable substituent atom.
2) with the atomic u-eight of the
4-
3.
i-
_
__“3----,
l_
Fig. 4.
Variation of the entropy cocfiicients (Table 2j-with the atomic weight of the substituent atom_
68
4
,
1,
r---=--
_
____eL---4
I0
F
0
I
t
P406083kxYm
Atcmic Fig
m&ht
5- Variation of the CnthaIpyfunctionco&Gents Cable 2) with the atomic weight of substituent
atom-
Fig. 6. Strtz~
of bromocydopmtane
used to calrlatc
rk
COdOl?lYff.
with possx%Ie confo-
(a) Bromocyclopentane
st~cturc
momentof inertiaproduct; (b) Possible axial conformer; (c) Possible equatorial
69 TABLE
2
CALCULATED
CONSTANTS
0, b AND c IN EQN (1)
a
BromocycIopro_me co S”
bx
102
cx 10s
Stand&d erroP
-1-7891 50.8437 47.8081 3.0357
735 7.37 4.22 3.15
-33.386 - 1.721 -0.8661 - 0.8550
0.2266 0.0249 0.050I 0.0686
-2-7016 522396 49.3369 39026
8.93 8.63 4.82 3.80
-3.817 - !.806 - 0.8789 - 0.9274
0.2465 0.0370 O-0462 0.0799
- 4.102 47.8924 45.1685 27239
9.06 8.16 4.56 3.60
-
3.832 I.534 0.7680 0.7658
0.2235 0.1055 O-0425 0.1257
-(F’-H;);T (H’-H;)jT
- 5.7489 48.2992 46.145? 2.1533
9.22 7.79 4.27 3.53
-3.86 - 1.358 - 0.6492 -0_7091
0.1967 0.0858 0.0372 0.1227
Iodoqclobutane (estimated) C” SZ -(F”-H;)JT (Ho-H;)IT
- 1.93 59.0 56.5 3.00
8.85 8.80 4.83 4.00
- 3.75
-0.175
-
-4.521 -2.300 -1.099 - I.201
0.2570 0.0265 0.0572 0.0766
-(Fe--6)/T (Ho-H,O)!T
Bromocyclobctanc co S’ -(I==-H&T (Ho- H;))rT
Chlorocyclobutane cg, S’ -(F=- H;)/T (HO- H;),fT
Ruorocyclobutane c, S’
BromocycIopentanc G S” -(F’-H&fT (Ho- H;))lT
- 1.7571 56.4023 52.9403 3-4621
10.86 IO_90 6.06 4.84
a standard error of V is the numberS, where S = of observations ; m is the number of independent v&ables: and Y, is the ith extrapolatedvalue of Y (cqn. 1).
-1.90 - 0.905
m-Isuchthatnisthenumber Y, is the ith calculated value of Y Uable
1) ;
Bromocyciopentane The thermodynamic functions (Table 1) for bromocyclopentane were calculated using the fundamental frequencies assigned by Durig et al. lo- The belief advanced by Durig et al. lo that the chloro- and bromocy~lopentane rings may not undergo pseudo rotation (form conformers) is indirectIy supported by VoveIie et al.’ 1 through their observations that the position of the bromine atom (axial or equatorial, Fig. 6) does not affect the fundamental frequencies. These considerations have permitted to calculate the thermodynamic functions for bromocyciopentane as a planar ring mole-
3015 1423 1200 1OSl 887 760 309
2957 1264 1165 1030 862 54s 273
kcqrlcncica
‘1
3020b 2962 1451 1092 808 633 2992 1227 1025 896
[V, cm’ 3005 2868 1262 486 78s 302 2977 1181 963 824
ihmocychbumna
’ 135.012
a=1
h * 8,356 IN = 51,501 IC = 56,377
3015” 2923 145s 1103 84X 530 2989 1266 1123 910
1
90.544
a=
f” = 33,439 1~ = 38,349
2967 1400 1207 851 717 IS9 1430 1172 940 286
G - 8,320
3005 2854 1288 1024 781 365 2979 1242 971 815
Clhrncyclobutnne
~~ONOCYCLOALKANES
’ All frcqucncics from ref. 1, b All froquoncics from ref. 8. o All frequcncics, oxccpt I50 cm’ this work,
120.97
Molecular Weight
UP1
Molecular shop0 factor, o
IA = 34.304 Ill p 5.105 IC - 32,695
2977 1459 1197 1015 699 143 1440 1159 938 247
PARAMETERS 01: IIAL~czNAI’ED
Principal momcnts” of incttia, g cnaax 10Jp
3078~ 1448 1238 1089 927 810 493
~undanwHn1
ihtttocyclopropmra
MoLEcUI.AR
TABLE 3
2992 2950 1361 1098 7R3 4.56 2966 1221 1057 835
2912 1472 1242 1079 750 166 1441 1161 921 371 2994@ 2875 I449 1219 1003 2Hl5 1403 1134 1003 742 231 742 452
2924 1473 I208 1178 2924 1477 1237 1028 803 305 8R6 51s 15od
149.02
f, a 15,661 I,, = 63.129 r, = 71.473
2976 2852 1315 1209 2976 2852 1282 I066 935 584 903 716 289
10, d Estlmnlcd, this work, see Fig* 7, o Calculated,
74,094
J,, = 19,887 I,, = 24,878 k =I 8,241
I, from rcf’,
3006b 2861 1453 1140 959 599 2988 1263 IO49 899
71 cule3 existing structurally in state as shown by Fig. 6a. This point is strengthened through the observation that JO% error in the I~ABc-pL_~ value would yield an inaccuracy for entropy and free energy function values of ~aI
Fig. 7. Estimztion
of the missing fundamental
ring puckering
frequency
for bromowclopcntaue.
ACCURACY
Since there was no available experimental evidence, it was not possible to compare the caknlated thermodynamic function values with the experimental data_ However, indirectly a measure of the accuracy of the presented thermodynamic function values (Table 1) may be obtained, as the structural and spectroscopic data used (Table 3) are highly accurate and none of the Wed compounds may undergo pseudo-rotation- In view of this, it is expected that the cakulated classical thermodynamic function values wiIl be within the possibie measurement error range.
The financial assistance of the National Research Council of Canada is gratefully acknowkdged. REFERENCES I W. G. Rotschild, 1. Chem. Phys., 44 (666) 3875. 2 F. M. XC.Lam and B. P. Dailey, J. Chcrn- P&s., 49 (1968) 1588_ 3 Y. Yukawa (Ed.), Handhok of Orgatzic StructzwaI Ana&sis, W_ k &njamin,
NCW
York. 1965.
72 4 H. Kim and W. D. Gwinn. f. Chem. Phys., 44 (1966) 865. 5 3. R. Durig and 1. N. WiJIis, J. Chem. Phys.. 52 (1970) 6108. 6 W. G. RotschiJd. J. Chem. Phys... 45 (1966) 3599. 7 W_ G. RotschiJd, 3. Chem. Phys., 44 (1966) 1712. 8 J. R. D&g, J. N. Willis and W. H. Green, J. Chem. Phys.., 54 (1971) 1547. 9 W. G. RotschiId and B. P. Dailey, J. Chern. Pkys., 36 (1962) 2931. JO J. R. Durig, 3. .M. Karrikcr and D. W. Wcrtz, J. Mur. Specrrosc., 31 (1969) 237. 1 I F. VoveIk A. Le Roy and S. Idiot, f. Mol. Srwcr.. I I (1972) 53. 12 University
of British CoIumbh
Computing
Centre,
“TRIP”
program,
1973.