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Influence of Isomerism of Alkanes on the Thermodynamic Properties of CyclohexaneAlkane Mixtures.

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CAS Registry numbers:
(la), 91-56-5; ( l b ) , 1127-59-9; ( f c ) , 391-12-8; (fd),6374-92-1; ( l e ) . 87-48-9 ( t ! .
61 1-09-6; (1s). 7477-63-6; (lh). 7298549-0; (li), 443-69-6; (lj), 324-03-8; ( l k ) .
20205-43-0; (Za), 11848-9; (Zb), 66176-17-8; (2c), 72985-50-3; (2d). 4693-00-9;
(Ze), 24088-82-2; (2fl, 4693-02-1; (2g). 63497-60-9; (Zh). 72985-514; (21).321.697; (2j), 321-50-6; (.la), 3597-63-5; (3b). 72985-52-5; (3c). 72985-53-6; (3d), 7298529-6, (3e), 72985-30-9 (3k), 72985-31-0.
[I]G. M . Coppola, G. E. Hardrmann, 0. R. Pfster, J. Org. Chem. 41, 825 (1976):
G. M . Coppola, G. E. Hardtmann, J . Heterocycl. Chem. 16, 829 (1979).
[2] H. Kolbe, J. Prakt. Chem. [2] 30,467 (1884); R. Dorsch, ibid. [2] 33, 32 (1886);
D. G. O'Sullivan, P. W.Sadler, J. Chem. SOC.1957, 2916.
131 R. A. Scherrer, A. Arbor, US-Pat. 3238201 (1966).
H
Table 1. Isatoic anhydrides (2) from isatins (1) with H Z 0 2in acetic acid; 2,3-dioxo-1,4-benzoxazines (3) from isatins (1) with H&08 in sulfuric acid [a)
R'
R3
R2
R4
[%I
(2)
M.p. ["C]
(dec.)
79
75
81
90
83
80
85
70
83
84
252-253
237-239
184-1 86
252-256
270-275
224-232
210-21 5
235-242
265-268
229-231
Yield
(3)
M. p. ["C]
in [2]
Yield
[%I
M.p. ["C]
(dec.)
233-235 dec.
277
95
89
82
95
95
285 [b]
247-249
207-210
255-257
3 18-320
90
278-284
~~
a
b
C
d
e
f
g
h
i
J
k
H
H
H
H
H
H
H
CH3
H
H
H
H
H
H
c1
Br
NOz
H
H
F
H
H
H
H
H
H
H
H
H
H
H
F
CH3
H
CH3
' 3 3
CI
H
H
CI
OCH,
H
H
CH3
254-256 dec.
270-275 dec.
220-230 dec.
260
241
[a] All compounds gave correct analyses and characteristic IR and NMR spectra. [b] M. p. 275-276 "C (dec.) 14)
an exothermic reaction. Isatoic anhydrides do not occur as
by-products.
Some of the compounds prepared, e.g. (3c) and (3d), are
very sensitive to hydrolysis even in weakly acid solution at
room temperature, so that mixtures of benzoxazine (3) and
N-(2-hydroxyphenyl)oxamidic acid (4) are sometimes obtained on work-up.
[4] K. Dickore, K. Sasse, K.-D. Bode, Justus Liebigs Ann. Chem. 733, 70
(1970).
[51 Houben-Weyl Methoden der organischen Chemie. Vol. 7/4. Thieme, Stuttgart 1968, p. 5.
161 G. Reissenweber, DOS 2925 175 (1979), BASF; G. Reissenweber, D. Mangold,
DOS 2944696 (1979), BASF.
Influence of Isomerism of Alkanes on the
Thermodynamic Properties of Cyclohexane/Alkane
Mixtures
Compared with the synthesis of 2,3-dioxo-I,Cbenzoxazines (3) from o-aminophenols and oxalyl chloride[41,the
synthesis from isatins (I) offers advantages, particularly for
the directed synthesis of derivatives substituted at the benzene ring. Thus, for example, preparation of the o-aminophenols required for the synthesis of (36) or (3c) is tedious and
not without difficulty, whereas the corresponding isatins are
readily
The isomers (2) and (3) can be easily and unequivocally
distinguished by mass spectrometry.
By Andreas Heintz, Riidiger N. Lichtenthaler, and Klaus
Schayer'']
Dedicated to Professor Matthias Seefetder on the occasion
of his 60th birthday
The various chemical structures of isomeric hydrocarbons
also lead to differences in thermodynamic behavior of the
pure isomers and of their mixtures with other compounds.
Owing to the industrial importance of such mixtures in isolation procedures, a knowledge of the so-called excess quantities AZM is important. For binary mixtures it holds that:
A&
(2): A suspension of (1) (1 mol) in glacial acetic acid (ca.
1000 ml) and conc. sulfuric acid (5 ml) is heated to ca. 30 " C .
It is then treated dropwise within 20 min with 1.1 mol hydrogen peroxide as a 30% aqueous solution and the reaction
temperature kept at 60-70°C by gentle cooling. After 2
hours' stirring and cooling to room temperature the precipitate is filtered off and washed with water.
(3): 1 mol of (1) is added to a solution of K2SZOs(1-1.5
mol) in ca. 1000 ml 85-95% sulfuric acid at 0 to 10 "C. After
stimng for a few minutes the solution is poured onto ice. The
precipitate is filtered off and washed with water.
Angew. Chem. h t . Ed. Engl. 19 (1980) No. 3
-XI
Z, - x ~ Z ,
(1)
The quantity Z may be, e. g. the enthalpy H , the entropy S,
the free energy G, or the volume V. AZM represents the difference between Z in the mixture (subscript M) and the contributions of the pure components 1 and 2; x , and x 2 are the
mole fractions.
As examples of our studies, Figure 1 shows the experimentally determined molar enthalpies of mixing AHM for mixtures of cyclohexane (c-C,) with n-octane (n-C,), 2,2,4-trimethylpentane
(i-C,), n-hexadecane
(n-C16), and
2,2,4,4,6,8,8-heptamethylnonane
(i-C,6).
['I
Received: December 11, 1979 [Z 397 IE]
German version: Angew. Chem. 92, 196 (1980)
=Z M
Prof. Dr. K. Schafer, Dr. A. Heintz, Prof. Dr. R. N. Lichtenthaler
Physikalisch-Chemisches Institut der Universitat
Im Neuenheimer Feld 253, D-6900 Heidelberg (Germany)
@ Verlag Chemie, GmbH, 6940 Weinheim, 1980
0570-0833/80/0303-0223
$02..50/0
223
The data were obtained with an isothermal flow calorimeter which has been described on a previous occasion[’].Figure 2 shows experimental results for the equimolar entropy
501
01
300
20C
100
4
0:5
1
Fig. 1 . Experimental molar enthalpies of mixing- AH, for mixtures of cyclohexane with isomeric alkanes as a function of the mole fraction x2lkane at 298.1 5 K/1
bar ( - O ) and 313.15 K / l bar (---.)-
of mixing ASM of various isomeric alkanes + c-c6 as a function of the number of carbon a t o m n. These data were obtained from measurements of the vapor pressure of the mixtures with a recently described vapor pressure apparatusfz1,
from which AGM was initially determined. The entropy of
mixing ASM could then be calculated with the aid of the
calorimetrically determined AHM values.
It is seen that AHM and ASM are considerably higher for
the n-alkane/c-C6 systems than AH, and ASM for the systems with branched isomers. It is seen from Figure 1 that
AH, decreases significantly with increasing temperature,
which is not the case with the branched isomers. Theoretical
rationalization of this difference in behavior is not only of interest from the standpoint of molecular physics but is also
important in practice in order to predict the excess quantities
over large ranges of temperature and pressure.
A theory suitable for treating mixtures of molecules of different sizes is that of Flory et
This theory employs experimental quantities of state of the pure components and requires for calculation of the excess quantities just a single adjustable parameter X12 which contains the difference between the segmental intermolecular interaction parameters
qv of identical and different molecules of the mixture. It
holds that
Adjustment of the theoretical expression for AHM to the
experimental data leads to widely differing XI2 values for
mixtures of the isomers with c-C6; e.g. xl2(i-c16+c-c6)=5.1
J cm-3 and Xl2(n-Ct6+C-C6)=16.5 J cm-3 at 298.15 K.
Moreover, the temperature dependence of AHM in the n-alkane/c-C6 mixtures cannot be described with a constant value of X,2; instead, lower XIz values are required at higher
temperature. For example X&-Clb+C-Cb)= 16.5 J ~ m at- ~
298.15 K and 14.1 J cm-3 at 313.15 K. This does not agree
with the simple Flory theory which stipulates that X12should
be constant as a molecular parameter. Nor can the large differences in X, of the isomeric pairs be explained by the differing numbers of CH3, CH2, and CH group increments
since the differences in interaction energy are slightl4I. Experimental results obtained on depolarized Rayleigh light
scattering showed that some degree of close range order exists in the pure n-alkanes, probably sterically favored partial
parallel orientations of molecular chain segments which are
also energetically stabilizedi5].
On mixing with a globular molecule such as c-C6 these ordered structures are destroyed, depending upon the mixing
ratio; this is associated with an endothermic contribution to
AH,. Thus AHu is considerably greater for n-alkanes than
for branched isomers which have practically no such ordered
structures. This also explains the higher ASM values of n-alkane/c-C6 mixtures since the entropy of the pure n-alkane is
smaller than for the corresponding branched isomer owing to
the ordered structure.
Application of a theory of rotational transformation of
simple molecules[61to chain segments permits derivation of
expressions for a orientation-dependent component of the
segmental interaction energies so that an effectively temperature dependent component must also be considered in addition to the expression valid for 7 (n-alkane) in eq. (2). It then
follows“I:
X z is the value of X12when T approaches infinity; the sec-
Fig. 2. Experimental equimolar entropies of mixing ASM for mixtures of cyclohexane with isomeric alkanes at 298.15 K as a function of the number of carbon
points for branched alkanes (i-C,=2,2atoms n. o points for n-alkanes,
dimethylpentane; X n i-C16r
,
see text).
.
224
0 Verlag Chemie, CmbH, 6940 Weinheim, 1980
ond factor in eq. (3) is temperature dependent and includes
the “orientational component” of X12.To has the formal significance of a transition temperature for orientation of the
chain segments. To and X : in eq. (3) can be determined
from the temperature dependence of Xi2. X z has an approximately constant value of 3.5 J cm-3 for n-alkane/c-C6
mixtures, while To lies about 10-30 K below the melting
point of the particular n-alkane. In fact, transition phenom-
0570-0833/80/0303-0224
$ 02.50/0
Angew. Chem. Inl. Ed. Engl. 19 (1980) No. 3
ena have already been observed for alkanes in the solid
statel'].
picture of the systems under study in terms of molecular
physics but also allow prediction of excess quantities in other
ranges of temperature and pressure.
Received: December 6, 1979 [Z 412 IE]
German version: Angew. Chem. 92, 209 (1980)
2c
[I]A . Heintz, R. N. Lichtenthaler, Ber. Bunsenges. Phys. Chem. 81, 921 (1977).
[2] D. Meixner, R. N. Lichtenfhaler, Ber. Bunsenges. Phys. Chem. 83, 561
(1979).
(31 P. J. Flory, R. A . Owoll, A . Vru, J. Am. Chem. SOC.86, 3507 (1964).
141 K Te Lam, P. Picker, D. Patterson, P. Tancrede, J. Chem. SOC.Faraday
Trans. 11, 70, 1465 (1974).
[S] P. Tancrede, P. Bothorel, P. de St. Romain, D. Patterson, J. Chem. Sw. Faraday Trans. 11, 73, 15,20 (1977).
161 K. SchaTer, Z.Phys. Chem. B 44, 127 (1939).
(71 H. L. Finke, M . E. Gross, G. Waddington, H. M . Huffman, J. Am. Chem. SOC.
76, 333 (1954).
(81 A. Heinfz, R. N. Lichtenthaler, Ber. Bunsenges. Phys. Chem. 83, 853 (1979).
191 A. Heinlz, Ber. Bunsenges. Phys. Chem. 83, 155 (1979).
15
IC
5
0
Complex Stabilization of 3-Oxopropadienylidene
( C 3 0 )with Pentacarbonylchromium(o)l**l
By Heinz Berke and Peter Harterl'l
-5
A facile entry to metal complexes containing carbene-analogous cumulene Ligands is possible uia propiolic acid derivatives[']. We have now been able to synthesize pentacarbony1(3-oxopropadienylidene)chromium(o) (1).
-10
(CO),CrI@
+
::
AgCaC-COzNa
C'
Fig. 3. Pressure dependence of enthalpy of mixing A(AHM) for n-Cs+cycIohexane and r-C,+cyclohexane at 298.15 K. ( - 0 ) calorimetric data, x indirect data
obtained from A V M .--- curves calculated with adjusted Xj2values.
In order to study the temperature dependence of the ordered structures, AHM of several alkane/c-C6 mixtures at
high pressure was determined in a modified flow calorimeter.
A recent repod8' concerns this apparatus. Figure 3
shows
A(AH,)=AH,
(high pressure) -AH,
(1 bar)
for n-Cs + c-C6 and i-Cs + c-c6. In addition to directly determined calorimetric experimental values, indirectly determined ones are also given, which were obtained from measurements of the excess volume AVM and its temperature dependence according to the following thermodynamic identity:
A(AHM)=(AVM- T . [ A ( A V M ) / A ~ ) ~
(4)
The excess volumes were established from density measurements of the mixtures and the pure components by a proven
new method[']. The broken curves in Figure 3 have been calculated with adjusted Xlz values. For i-Cs, Xlzremains pressure-constant (7.2 J cm-3), while for the n-Cs mixture Xlzincreases from 9.7 J cm-3 at 1 bar to 10.7 J cm-3 at 290 bar.
According to eq. (3), an increase of Xl, means an increase in
To with pressure. This is to be expected since To is shown in
ref.161to be proportional to the energy required to bring
about the transition. This energy is all the greater, the higher
the pressure (i. e. the density) since steric and energetic hindrance of the transition are all the greater at higher density.
The extended Flory theory thus permits a consistent description of the excess quantities for mixtures of isomeric alkanes with cyclohexane. They provide not only an accurate
Angew. Chem. Int. Ed. Engl. 19 (1980) No. 3
On using the method of Connor et al.lzl with pentacarbonyliodochromate and the silver acetylide derivative of sodium propiolate as starting substances, presumably a r-complex is initially formed (IR spectroscopic detection), which
we did not isolate but allowed to react further with thiophosgene. Chromatographic separation of the product mixture afforded (1) in ca. 35% yield. Losses on purification due to the
high volatility of this black-violet compound (dec. pt. 32 "C),
which is stable for some time in the crystalline and pure state
at room temperature, can hardly be avoided. The structure of
(1) follows from spectroscopic findings and chemical characterization.
In the IR spectrum (solution in n-hexane) the absorptions
of the carbonyl ligands correspond to C, symmetry [2074 w
(Al), 1977 s (E), 1971 cm-' m (Al)]. A further band at 2028
cm-' (s) is assigned to the vibration in the complex ( 1 ) which
is equivalent to the v1 vibration of free C3013],appearing, as
expected, at a lower wavelength. In the gas phase, two absorptions of weak intensity are observed [2005 m (Al), 2001
cm-' s (E)]. No band, which could be assigned to the v2-vibration of the C 3 0 ligand, has been observed so far. Even in
and on carbonylmethyl cominvestigations on free c30[31
p o u n d ~ [no
~ ' such band has ever been found.
The "C-NMR data of (I) are listed in Table 1.
p] Dr. H. Berke, Dipl.-Chem. P. Harter
Fakultat fur Chemie der Universitat
Postfach 5560, D-7750Konstanz (Germany)
I**]
This work was supported by the Deutsche Farschungsgemeinschaft and by
Research Facilities of the Universitat Konstanz.
0 Verlag Chemie, GmbH, 6940 Weinheim, 1980
0570-0833/80/0303-0225
.%OZ.SO/O
225
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thermodynamics, properties, isomerism, mixtures, alkane, cyclohexanealkane, influence
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