NOTES
1552 TABLEI1 MOLECULAR IONIZATION POTENTIALS OF SOME THIACYCLOALKANE~ (IN E.v.) Molecule
Calculateda
Measured
1.55 1.99 13.31 IO. 46 9.0Sb
1.55
1.25
13:31 8.87 (8.87)
13:04 8.87
(8.87)
8.8’ib
CHaCHCHzS
9.02
8.38
8.51
8.6c
YHeCHsCH2Y
8.43b
..
..
8. 64d
b C
e
f CHTCH~S L-J
L-J
C%Ha+from propylene sulfide is accompanied by H. This value the neutral fragments CH2S is in good agreement with that of 280 kcal./mole reported by Field and Frank1in.lo m/e = 37.-The formation of C3H+ from propylene sulfide appears to occur by the process in Table I. The abundance of this ion was quite small and therefore the appearance potential was rather difficult to measure; however, fair agreement is obtained assuming that the neutral fragments S Hz 3. 3H are formed. We calculate AHf+(C$H) = 322 kcal./mole; 309 kcal./mole is reported by Field and Franklin.’O m/e = 38.-CsH2+ is believed to be formed by a process which includes the neutral fragments H2S 2H. The heat of formation for CIH+ calculated from the energetics for this process is 363 kcal./ mole, in good agreement with the literature value of 360 kcal./mole.1° Another process which cannot be entirely ruled out, as indicated by the energetics, is C3HsS+ C3H2+ SH H Hz; this leads t o eHr+(C3Nz)= 379 kcal./mole. m/e = 39.-The energetics indicate that CIH3+ is formed by a process which includes the neutral fragments Hz H S. The heat of formation calculated for CaH3+is 281 kcal./mole, in agreement with the literature.1° m/e = 40.-The ion at m/e 40 is CaH4+ and the thermochemical calculations result in ARf+(CaHd) = 298 kcal./mole, assuming the neutral fragments to be S Hz. m/e = 4l.-This ion is the dominant specie in the propylene sulfide mass spectrum and can only be C3H6+. Only fair agreement between AHf+(CBH6)= 253 kcal./mole and various literature valueslO is noted for the process C3HsS+ C3He+ SH, but the energetics rule out any other process. m/e = 45.--If the formation of CRS+ from propylene sulfide is accompanied by the neutral H, aHf+(CHS) = 279 kcal./ fragments CzHa mole, which is in good agreement with the heats of formation for this ion obtained by Gallegos and Kiserz for other sulfur-cont aining heterocyclics and values obtained by us for straight-chain sulfides.5 Also possible, however, is a process in which the neutral fragments C2H3 3.Hz are formed.
+
+
+
+ +
+ +
+
+
+
(11) J. L. Franklin, J. Chsm. Phys.. 22, 1304 (1964).
From the energetics for this process, AHf+(CHS) = 280 kcal./mole. m/e = 46.-This ion is quite abundant in the mass spectrum of propylene sulfide and can only be CHzS+. From the measured appearance potential AHf+(CHZS) = 251 kcal./mole if the accompanying neutral fragments are CzHz Hz. This is somewhat high in comparison to values given by Gallegos and Kiser2.$but other processes are eliminated by the energetics. m/e = 47.-A heat of formation of 224 kcal./ mole is calculated for CH3S+ if the neutral frag€1. This result is in good agreements are CzHz ment with the literature value of 222 kcal./mole.10 m/e = 58.-The ion of m/e = 58 is C2H2S+and is thought to be formed by the process shown in Table I. The heat of formation of CzHzS+ = 295 kcal./mole is somewhat higher than those reported by Gallegos and Kiseras3but other processes are indicated by energetic considerations to be less probable. m/e = 59.-This ion is thought to be formed by the removal of a CHa group from the parent molecule. AHr +(C2H3S) = 271 kcal./mole agrees rather poorly with literature values,: but any other process is less probable, as indicated by the tbermochemical calculations. m/e = 73.-Abstraction of a hydrogen atom from C3HsS+ results in the ion m/e = 73. We calculate AHf+(CaH6S) = 226 kcal./mole. The heat of formation of this ion has not been determined previously. m/e = 74.-This is the parent molecule-ion from propylene sulfide. Using the experimentally determined ionization potential, AHf +(C3H6S) = 217 kcal./mole. This is in good agreement with the value of 220 kcal./mole calculated from the trimethylene sulfide study.3 This also indicates that our estimat)ion of the heat of formation of propylene sulfide gave a reasonable value.
+
The first column gives the parameters due to Franklin (see ref. 11); the second and third columns assume that the -CHCHzS unit may be treated as a group and the other parameters are those given by Franklin. b See ref. 2. This work. L.D. Isaacs, W. C. Price, and R. G. Ridley, “Vacuum Ultraviolet Spectra and Molecular Ionization Potentials,” in “The Threshold of Space,” Edited by M. Zelikoff, Pergamon Press, Ltd., London, 1957, pp. 143-151.
+
Vol. 66
+
THE AFFINITY OF HYDROHALIC ACIDS FQR TRI-wOCTYLAMPNE BY ARCHIES. WILSONAND XED A. WOGMAN Ilanjoi d Laboralorzes Operatzon, General Electric C o m p a n y , Rachland, Washrngton Received February 13, 196d
The salts of high molecular weight tcrtiary nmincs are soluble in a variety of organic solvents xhich are immiscible with water. This property of the amines has made possible the extraction of metallic complex ions and other anions from acidic aqueous solutions. We have been interested in understanding the factors which are important in these extractions. In the course of our study, \\+e have measured the affinity of the hydrohalic acids for tri-noctylamine (TOA) dissolved in a variety of solvents and a t different concentrations. In addition to the affinity measurements, the extraction of the (1) E. L. Smith and J. E. Page, J . SOC.Chem. I n d . , 67, 48 (1948). (2) W. E. Keder, J. C. Sheppard, and A. S. Wilson, J . I n o w . Nurl. Cham., 12, 327 (1960). (3) F. L. Moore, “Liquid Extraction with High-Molecular-Weight
Amines,” NAS-NS-3101 (1960).
NOTES
August, :I962 hydrohalic acids into aromatic solvent solutions of TOA also has been measured as a function of aqueous mid concentrations. Experimental A. Chemicals.---TOA, obtained from the Chemical Procurement Co., contained a colored impurity which was removed by crystallizing the aomine hydrochloride etherate four times from ether a t -30 . The amine was obtained by neutralization of this salt and had an equivalent weight of 339.7 0.8 g. as determined by the method of C. D. Wagner, et al.4 No secondary or primary amine wets detected in the TOA, which analyzed: C’, 81.72; H, 14.58; and N, 4.02. The index of refraction was l.44725Das compared to the literatures value, l .45019.6~. Hydrofluoric and hydrochloric acids were Baker and Adamson’s C.P. grade and were used as received. Ilydrobromic acid, Baker and Adamson’s reagent grade, was purified by aerating with H2S; distilling, and collecting the fraction boiling a t 126 i 1 Hydriodic acid solutions were prepared from diluted Merck’s reagent grade acid by HzS aeration and boiling to coagulate the sulfur and to remove H2S. The solutions, free of 5 - 2 and were filtered and used the same day. Toluene and xylene, Baker and Adamson’s purified grade, cyclohexane, Eastman’s spectro grade, and nitrobenzene, Eastman’s White Label grade, were used as received. Commercial Solventc’ manufacturing grade 2-nitropropane was distilled and the fraction boiling at 119.3-119.5” was used. Water was triply distilled. €3. Procedure.-The TOA solutions were pypared volumetrically from weighed amounts of the amine. Measured volumes of a, TOA solution and water were equilibrated with enough acid to convert half of the amine to its salt and the pH of the resulting aqueous phase was determined with a Beckman Zeromatic meter using a saturated calomel electrode and a glass electrode. Titrations of the pure solvents showed that almost no acid was extracted. I n the acid extraction experiments, the acid concentration in each phase was determined by standard acidimetry. All experiments were conducted a t 25.0’.
.
154
.
t
Tn 4.1 at 28& HF 3
I
H I a!Ol M TOA-toluene 0 HBr 0.W9 ETOA-toluene A HCI 0.21 fiT0A-xylene o HF 0.1 MTOA-toluene
i
\
I
’ -
2
8.
!
0
IW
10
01
1
a
M HX.
Fig. 1.-The extraction of the hydrohalic acids by TC with E, moles of acid to moles of amine, plotted us. aqueo acid concentration.
I n Table I are listed the apparent affinity co stants a t three different TOA concentrations four different solvents for the hydrohalic acic The K’ values for the two lower TOA coricentr tions increase in each solvent in the order HC HBr, HI. This observation, that the largest ic has the greatest tendency to extract from tl aqueous phase into the organic phase, is that e pected as recently discussed by Diamond ar Tuck.’ Moreover, a linear relationship exie between log K’ a,nd the crystal ionic radius of tl halide ion for a given solvent and TOA concentr Results and Discussion tion. A comparison of the difference between 1( Affinity Constants.-The reactions of aqueous I\
(7) R. 31.Diamond a n d D. G . Tuck, “Progress in Inorganic Chemi try,’’ Interscience Publishers, New York, N. Y . , 1960, p. 122. ( 8 ) R. M. Fuoss a n d F. Accascinn, “Electrolytic Conductance T^’^_^^.
---
n
L,
1
..
7-
XT
TT
1
.T
-7
*a?-
NOTES
1554 TABLE I LOGK'
'ro.4, ;Li
0.1 0.1 0.2 1.0 0.1 0.2 1.0 0.1 0.2 1.0 IXelect8ric constant
Solvent c:yciohexane
... 3.03 3.35" 5,14b 4.11 4.55" 6.87" 5.95 6.84" 9.40" 2.02 at
'Lo
Toluene
Z-Nltiopiopane
4.25 4.87 5.25 5.94 6 08 6 68 7.69 7 98 8 80 10.23 2.38 at 25 a
8.44 8.81 9.24' 8 91 9 89 11.00~ 10.78 11.59 10.87" 25 52 at 20
..
Nitrobenzene
... 8.60 9.22
9.10" 9.68 10.19 10.84C 11.34 12.27 12.90" 34.82 a t 25 a
Vol. 66
Aqueous (DzO)silver nitrate solutions of known concentration (0.6 to 6.0 moles/l.) were saturated with the desired hydrocarbon. The proton magnetic resonance spectra of the aqueous solutions were observed a t a frequency of 40 Alc.p.s. g-ith a Varian Model V 4300 spectrometer. All chemical shifts were measured relative to the impurity HzO signal by the sideband technique, using an electronic rounter to measure the modulation frequency. From the ionic diamagnetic susceptibilities given by Selwood3 and the HzO susceptibility given by Pople, et aZ.,2 it was established that the chemical shifts between the HzO signals of the ionic solutions and that of pure mater mere satisfactorily accounted for by bulk susceptibility corrections2 alone. For the studies on the aromatics, T5-e also measured the total amount of hydrocarbon taken up bv each solution. This was done by extracting the hydrocarbon from the aqueous solution with isooctane4 and determining the amount of extracted h) drocarbon from the intensitv of an infrared absorption band (14.85 p for benzene and 13.75 p for toluene) and a previously prepared calibration curve.
Results Thc n.m.r. spectra of the olefin-containing aquci i h b r b foinied during titration ous solutions were independent of the AgKOs 0 h 1.I iatlier than 1 0 1.1 concentration, indicating the presence of a single I)y Shevcheiiko, et C L L . , ~ that ~ the species (-4HH03)- species, presumably the 1:1 complex. The pertiHXO, v-a\$.important. Similar species for the nent chemical shift data for the olefinic hydrohydrohalic acids also may be considered. carbons are given in Table I. The data in column I t appears from Fig. 1 that the stronger the acid, three of this table are in fair agreement with the the less likelihood there is of excess acid extraction. findings of Powell and Sheppard.5 The values of Hydrofluoric acid presents a unique case because 6 in the final column are the changes in chemical apparently the extracted species, even in low shift due to complex formation. This symbol aqueous acid concentration, does not predominate will be used for the same purpose throughout the as ,4HF, but most likely it is AH(HF2). The remainder of the note. For the two olefins, the value of FZ rises as high as four when the amine &values of corresponding protons (relative to the solution is equilibrated with 28 111 hydrofluoric double bond) are very siinilar; it is inferred that acid. this will be true of other olefins as well. The n.m.r. spectra of the aromatic-containing Acknowledgments.-We wish to express our thanks to Mrs. W. G. Artman, who assisted in the aqueous solutions varied iTith the AgXOs concenlaboratory. This work was performed under Con- tration, but every spectrum contained only a single tract No. AT(45-1)-1350 for the U. S . Atomic absorption due to aromatic protons. These features can be understood in terms of rapid exchange Eriergy Commission. between several different species in equilibrium (1 1 ) v' I' \ h e \ ( lirnho \ h ilirriidt L ' A ~ l l 1d with one another.6 Aridrems and Keefer h a w l'c.tro\ rl I!/ \ rn,gnn K h i m , 5, 1852 (1Y00) studied4the equilibria in these systems and found evidence for the existence of free aromatic, 1 : I PROTOX CHEMICAL SHIFTS IN PI complex, and 1:2 complex, i.e., Ar, hr,Ag+, and COMPLEXES Ar.Ag2++. Furthermore, they were able to evaluate the two appropriate equilibriunl constants Bl ,J c. SC1II.G Ahn R J. XIkRTIV for both benzene and toluene. (,zclj K r w u h & I ) P V d O p f 7 I E i i / , cOinpa?iu, I'kltYinLluh In snrh equilibrium systems, thc observed Rerezurd P'ehiuarv 16 1962 chernical shift of a, particular proton type can be The fact that certain species form pi complexes1 written as an average of those in the various with aromatics and olefinic hydrocarbons is well species6; Le. established. However, only few of the known = xoso x161 x262 (1) complexes hare been studied in any detail. The dependence on electronic environment of the chemiI n this expression, the brackets signify the obcal shifts obtained from high-resolution nuclear magnetic resonance cxperimentsl makes that served shifts; x0 and 6o represent, respectively, technique an attractive one for such studies. In the fraction of hydrocarbon which is uncomplexed this note, we present a brief study of the proton and the chemical shift of that form; XI, 61, x2, and chemical shifts in aqueous silver ion complexes of a2 have similar meanings for the 1: 1 and 1: 2 complexes, respectively. 111 thc following discussion, cyclohexene, cis-2-butene, benzene, and toluene all shifts are referred to the uncomplexed moleExperimental All experiments were performed in an air-conditioned cules, whose shifts from the reference H 2 0 signal O
u o orgdnic plisses foilnod duiing titiation
Tinee organic The concentration of anline n a s
h ~ n J ~ l O ~ ~ l ~ l l l l > \ ,
~ ' r i l i i Y d t ~ J l i i ~ G
+
room, whose temperature mas regulated to within d22'F.
+
(3) P. W Selwood "Magnetoohemlstry," 2nd E d Intersclence Pub(1) R 9 Mulliken J A m Chem S o c , 72, 800 (1960) '14, 811 lishers, Ne, Yoik N P 1958, p 78 (1952) J Pkya Chew 66, 801 (1952) (4) L J 4ndreas and R 31 Keefer I 4 m Chem So( 11, 7614 (2) I 1 P o p l ~l4 0 iihnrxdet and I1 i Rernslrin, III~II-HR'Io- (1411)) 72 3114 (lYj0) iiition Kuclw.r LIdgnetic Rtijonuwc ' Z I ~ < r i d \ \ 11111 Uooh Co I n c ( 3 ) I ) R Pone11 snrl N S l i q ~ ~ , a i d I . C ' h i i i ~ 301 2 1 l ' J (I'JbO) h ~ Yoih n X I 1'339 (I,) ltcfeicncc 2 , Cliaptei 10
