J . Phys. Chem. 1985, 89, 38-41
38
The HSO luminescence from the reaction of (CH& and O3 is now discussed. The emission from HSO is undoubtedly due to reaction 3, since the HSO* spectrum of Figure 5 is virtually identical with that of Schurath et al.,1° who have shown that HSO* is most likely formed by reaction 3. Our observation of HSO* in this reaction system implies rather interesting kinetics for formation of the HS radical. Involvement of the HS radical is also suggested by the ozone dependence of Figure 8b. The greater than first-order dependence of Figure 8b implies that a radical, highly reactive with the walls, is involved in competitive consecutive reactions leading to the emitter. The approximately first-order dependence on (CH3S)2pressure, shown in Figure 8a, implies that (CH3S), is not involved in a reaction with a highly reactive radical species to form the HS radical. Although the source of HS in the reaction of (CH,S), with ozone may not be clearly elucidated by these data, certain possibilities are implied. The observation of HSO emission at relatively low pressure, -10 mtorr total, suggests that HS is not formed through an involved chain of reactions of highly reactive intermediates. We suggest that HS is formed by a hydrogen transfer during the rearrangement of an energy-rich production of the highly exoergic reaction
-
CH3S + O3
CH3S0
+ O2 +
=56 kcal mol-’
(17)
The C H 3 S 0 product can be formed with as much as 56 kcal mol-’ and could undergo subsequent rearrangement as follows CH3SO* CHzO HS (18) +
+
Although there is no direct evidence, the forms of the pressure dependences support this assertion. The pronounced decline in intensity beyond the maxima of the pressure dependences observed in Figure 8, a and b, demonstrates that some intermediate is efficiently quenched by both reactants. Participation of the CH3S radical in the chain leading to HSO’ is also suggested by the greater than first-order behavior of the ozone pressure dependence, since CH3Swas also proposed as an intermediate leading to SO2* and was responsible for the second-order dependence on ozone as discussed above.
Summary In extending our work on the low-pressure ozonolysis of simple sulfides, we have observed chemiluminescence from electronically excited SOzin the reaction of ozone with dimethyl sulfoxide and dimethyl disulfide. We have proposed mechanisms for the formation of the emitter based on the spectra, pressure dependences, and results of previous work. We have also obtained a chemiluminescence spectrum of the HSO radical in the reaction of ozone with dimethyl disulfide, suggesting interesting kinetics for formation of this species. Acknowledgment. We acknowledge the Graduate School of the University of Minnesota for partial support of this research and the Cooperative Institute for Research in Environmental Sciences for the facilities used in preparing this manuscript. Registry NO.03,10028-15-6; (CHJ,SO, 67-68-5; (CHjS)2,624-92-0; S02, 7446-09-5; HSO, 62470-71-7.
Very Low Pressure Pyrolyds of Furan, 2-Methytfuran, and 2,5-Dimethylfuran. The Stability of the Furan Ring M. A. Grela, V. T. Amorebieta, and A. J. Colussi* Department of Chemistry, University of Mar Del Plata, 7600 Mar Del Plata, Argentina (Received: June 8, 1984)
Furan (F), 2-methylfuran (MF), and 2,5-dimethylfuran (DMF) decompose between 1050 and 1270 K by ring breakdown unimolecular reactions. Loss of carbon monoxide is either the exclusive process or a major one in the case of F and MF or DMF decompositions, respectively. A common mechanism involving skeletal isomerization of the furans via cyclopropenylcarbonyl intermediates competing with decomposition through stabilized biradicals is proposed. The analysis of kinetic data leads to similar overall activation parameters for the three furans.
Introduction Reliable information on the high-temperature behavior of heterocyclic compounds is sparsel-“ and almost nonexistent for the important class of fivemembered heteroaromatic ringss This fact contrasts with the widespread natural Occurrence of these species and the growing recognition of their role in several fields such as air pollution,6 petroleum refining, and coal liquefaction and gasification processes.’ Thus, in addition to the general interest in the possible decomposition modes of furan and its derivatives, basic data on the stabiity of the furan units present in coal structure may help to understand the phenomenon of increased coal reactivity after thermal treatment.* (1) Braslavsky, S.;Heicklen, J. Chem. Rev. 1977, 77, 473.
(2).Frey, H. M.;Walsh, R. ‘Gas Kinetics and Energy Transfer”; The Chemical Society: London, 1978; Vol. 3, p 1. (3) Robinson, P. J. “Reaction Kinetics”; The Chemical Society: London, 1975; VOI. 1, pp 146-9. (4) Robinson, P. J.; Holbrook, K. A. “Unimolecular Reactions”; Wiley: New York, 1972; p 214. ( 5 ) Klute, C. H.; Walters, W. P. J . Am. Chem. Sac. 1946, 68, 506. (6) Lee, J. H.; Tang, I. N. J . Chem. Phys. 1982, 77,4459. (7) Sickles, J. E.; Ripperton, L. A.; Eaton, W. C.; Wright, R. S.Environmental Protection Agency Publication: Washington, DC; EPA-600/778-029.
0022-3654/85/2089-0038$01.50/0
In this paper we report a kinetic study of the thermal unimolecular decompositions of furan, 2-methylfuran, and 2,S-dimethylfuran under very low pressure conditions, reactions 1 and 2, which have not been hitherto inve~tigated.~
F. R=H MF. R=CH, Q ,R
-
CO
+
CH ,,
H$
+
C6H6
(2)
DMF, R=CH3
All species seem to open their rings to produce stabilized biradicals. Such biradicals, whose thermochemistry is at least compatible with estimates based on simple additivity rules,l0 finally convert into the observed products after undergoing plausible intramolecular H-atom transfers. The fact that D M F also gives carbon monoxide reveals concomitant rearrangement reactions proceeding at competitive rates through valence isomers of the ( 8 ) Haggin, J. Chem. Eng. News 1982, 60 (jlZ), 17.
0 1985 American Chemical Society
The Journal of Physical Chemistry, Vol. 89, No. 1 , 1985 39
Low-Pressure Pyrolysis of Furans furan ring.g Overall rates of ring decay are in the range predicted for simple scission reactions of exo /3 C-C bonds producing benzylic-type radicals."
Experimental Section The technique, which has been described in detail elswhere,I2 involves a heatable molecular flow reactor operating a t very low pressures (- 1 mtorr). Product analysis is continuously performed by an on-line mass spectrometer (EMBA 11, Extranuclear Labs). Under these conditions the reactants become thermalized in a few gas-wall collisions and subsequently undergo unimolecular decomposition in the falloff region.I2J3 The resulting fragments leave the reactor before engaging in secondary bimolecular reactions. This feature is particularly useful in the present case since the nature of the products suggests that pyrolysis at conventional pressures would inevitably result in Diels-Alder polymerization processes involving the furan ring (see be lo^).^ The reactor was attached to the mass spectrometer in two different configurations. In the first one, effusing gases were admitted to the differential pumping chamber of the mass spectrometer where a molecular beam is created. The beam then enters the main chamber through a 1-mm collimating aperture; it is modulated, ionized by electron impact, and analyzed with a quadrupole mass filter. The output is finally processed by a lock-in amplifier. The operation of the instrument in this mode has been recently p r e ~ e n t e d . ' ~It can be shown that the phase shift 'pj of an ion of mass mj produced by fragmentation of a molecular ion M+ is given by the equationI4 'pj
+
= a ( M / T ) 1 / 2 bm,ll2
+ cpo
(1)
where a, b, and cpo include instrumental parameters which may be fixed in a particular experiment. For a single gas of mass M at constant temperature T the phase shifts of its fragment ions should give a linear 'pj vs. m,'I2 plot. Conversely, if an ion mj derives from two species M I and M,, (p, will depart from such behavior depending on the composition of the mixture and the relative intensity of the peak a t m, in the mass spectra of both M I and M2. In this manner it is possible to analyze simple mixtures by mass spectrometry and assign the likely precursors to common fragment ions. Phase shifts could be routinely measured to within (f2O). Approximate ionization potentials (IP) were determined by signal extrapolation to zero ion current using the difference method relative to H 2 0 or benzene.I5 Alternatively, the reactor was directly connected to the main chamber. Now a metal baffle shielded the ionizer region from thermal radiation and scattered the beam simultaneously. Since free radicals are known to readily react upon collision with cold metal surfaces, molecular beam sampling is essential to confirm ~n their presence (or absence) among the products of r e a ~ t i o n . ' O the other hand, the temperature dependence of dissociative ionization, which modifies mass spectral patterns of stable polyatomic molecules, introduces a basic but generally unrecognized difficulty in quantitative analysis by mass ~pectrometry.'~Previous thermalization of hot gases following scattering on the baffle eliminates this complication and alows kinetic measurements based on peak intensities. In these experiments, F, MF, and D M F decomposed at measurable rates according to reactions 1 and 2 between 1100 and 1250, 1130 and 1240, and 1060 and 1150 K respectively. The extent of decomposition was followed by the decay of molecular (9) Srinivasan, R. J. Am. Chem. SOC.1967, 89, 4812. (10) Benson, S. W. 'Thermochemical Kinetics", 2nd ed.; Wiley: New York, 1976. (11) McMillen, D. F.; Golden, D. M. Annu. Reu. Pbys.Chem. 1982, 33, 493. (12) Golden, D. M.; Spokes, G. N.; Benson, S. W. Angew. Chem., In?. Ed. Eng. 1973, 12, 534. (13) Colussi, A. J.; Zabel, F.; Benson, S. W. In?.J. Chem. Kine?. 1977, 9, 161. (14) Amorebieta, V. T.; Colussi, A. J. J . Phys. Chem. 1982, 86, 2760. (15) Foner, . N. Adu. At. Mol.Phys. 1966, 2, 1.
10.0
7
'0
3
01
1050
1150
1250
T/K Figure 1. The unimolecular rate constants kuni for furan (F), 2methylfuran (MF), and 2,Sdimethylfuran (DMF) as functions of temperature. Solid lines were calculated from the Arrhenius expressions derived in the text after accounting for falloff effects.
ion signal intensities at m / z 68 (F), 82 (MF), and 96 (DMF). Rate constants were calculated from the fraction of reactant decomposed at each temperature,f, by the expression k~ = kf/(l -A, where k, is the rate constant for escape from the reactor: k,(s-') = 0.196 (T/M)'/' ( M in amu). The gas-wall collision frequency, which determines the degree of falloff, is given by w(s-l) = 4.0 X lo3(T/M)'/2.12*13 The corresponding collision efficiencies were estimated from Gilbert's empirical ruleI6 rather than by assuming 8, = 1 as in earlier work.13 As a check we have also verified that kunifor the unimolecular decomposition of ethylbenzene agrees well with recent data obtained in a similar system." The experimental results for kuniare shown in Figure 1. We reserve the symbols kland k2 for the high-pressure limits of kuni of reactions 1 and 2 which, although they refer to the same processes, are numerically different. Furan was prepared from 2-furaldehyde via decarboxylation of 2-furoic acid; 2-methylfuran was produced by catalytic hydrogenation of 2-furaldehyde; and 2,5-dimethylfuran was obtained by intramolecular condensation of 2,5-hexanedione.'* All products were purified by distillation under vacuum and gave mass spectra identical with those reported in the 1 i t e r a t ~ r e . I ~
Results and Discussion Mass spectra of effusing reaction mixtures, obtained at 15 eV to minimize ion fragmentation, indicated the presence of new species with ions at m / z 40 (C3H4) and 28 (CO) in the pyrolysis of furan and at m / z 54 (C4HS), 39 (C3H3),and 28 in the case of 2-methylfuran. This is taken as evidence of the proposed stoichiometry for reaction 1. The peak a t m / z 39 is ascribed to the fragment (M- 15)' of the molecular ion of mass 54. The identity of the species with molecular ions at m/z 40 and 54 could not be definitely established by mass spectrometry since the differences among the reported ionization potentials of the several isomers of C3H4fall within the precision attainable with a polychromatic electron beam (A0.3 eV). Thus, for example, the IP's of allene, cyclopropene, and propyne are 10.16,9.95, and 10.36 eV, respectively.20 It should be pointed out, however, that cy(16) Gilbert, R. G. Int. J . Chem. Kiner. 1982, 14, 447. (17) Robaugh, D. A.; Stein, S. E. Int. J . Chem. Kiner. 1981, 13, 445. (18) Weygand, C.; Hilgetag, G. "Preparative Organic Chemistry"; Wiley: New York, 1972. (19) Stenhagen, E.; Abrahamson, S.; McLafferty, F. W. "Registry of Mass Spectral Data"; Wiley: New York, 1974; Vol. 1.
40
The Journal of Physical Chemistry, Vol. 89, No. 1, 1985
Scheme I
Grela et al. TABLE I: Thermodynamic Data
C,, eu A H f , 3 w ~ ,S03w K, kcal/mol eu
species furan“ 2-methylfuranb 2,5-dimethylfuranb CHZ=CHCH2CHOb CH=CHCHCHOb
-8.3 -16.8 -25.5 -18.1 65.7
63.9 73.9 81.3 81.7 80.2
300
600
800
1000
K
K
K
K
15.8 22.1 28.4 22.9 21.4
29.3 39.8 50.3 34.2 30.3
34.4 37.9 46.3 50.9 58.2 63.9 40.0 44.1 34.7 37.7
‘Reference 23. *Reference 10.
clopropene is expected to rapidly isomerize to propyne under present conditions.21 Products of reaction 2 gave more complex mass spectra. Thus major peaks at m / z 18 (H’O), 28 (CO), 66 (C5H6), and 78 (C6H6)and a minor one at m / z 68 (C&) were detected. Their identities were carefully investigated. For example, the peak at m / z 28 is not a fragment ion but actually corresponds to carbon monoxide since its measured phase shift, ‘p28, is almost identical with the one calculated from eq I for a neutral species of mass A4 = 28. Moreover, an approximate determination of its ionization potential gave a value of I P = (13.6 f 0.3) eV in satisfactory agreement with literature data for CO.’O The peaks at m / z 66 and 78 are probably alkynes rather than the more stable isomers cyclopentadiene and benzene. This conclusion was reached by comparing their measured ionization potentials IPT8= 9.9 f 0.3 eV and IPs6 = 10.3 f 0.3 eV with those of benzene (IP = 9.25 eV), cyclopentadiene (IP = 8.9 eV), and (CH=C-CH,)2 (IP = 10.35 eV).’O The peak at m / z 68 (C5H8)is ascribed to the molecular ion of a primary product which further decomposes into CSH6by Hz elimination. In this connection we have verified that formaldehyde ( m / z 30) is stable under the present conditions and therefore its absence among the products strongly suggests that the m / z 66 peak does not correspond to a primary species. Moreover, the ratio of intensities of the m / z 68 and 96 peaks (168/196) displays a maximum at about 1050 K as would be expected for an intermediate species. A brief reflection about the origin of the products of reaction 2 reveals that (1) formation of carbon monoxide requires a previous skeletal rearrangement of 2,5-dimethylfuran to 2,4-dimethylfuran to place an easily transferable H atom on C5, like furan and 2-methylfuraq and (2) the loss of water clearly implies a hydroxylic precursor whose origin must be traced to a biradical intermediate. Isomerization to 2,4-DMF can be best rationalized as occurring through a valence isomer of the furan ring. Based on thermochemical arguments’O we propose cyclopropenylcarbonyl derivatives, rather than Dewar furans, as the lowest-lying intermediates capable of accomplishing the expected transformation. The marginal stability of these species indicates that a cyclopropene ring a to a carbonyl group easily expands back to furans by a concerted process” since it is known to open up only at higher temperatures.21 The required H-atom shifts yielding a formyl-type radical center or an alcohol, the immediate predecessors of CO and HzO should occur after a suitable biradical has been formed and therefore we propose the mechanism shown in Scheme I for the decomposition of 2,5-dimethylfuran. A similar, but simpler, scheme can be easily adapted to the decomposition of furan and 2-methylfuran. The interconversion between furans and cyclopropenylcarbonyl species, reactions 3 and -3, must be competitive with ring opening, reaction 4, at 1100 (20) Franklin, J. L.; Dillard, J. G.; Rosenstock, H. M.; Herron, J. T.; Draxl, K.; Field, F. H. Natl. Stand. Ref. Data Ser. (US.Natl. Bur. Stand.) 1969, No. 26. (21) Bailey, I. M.; Walsh, R. J. Chem. Soc., Faraday Trans. 1 1978, 74, 1146. (22) Turro, N.J. ‘‘Modern Molecular Photochemistry”; Benjamin: Menlo Park, CA, 1978; p 512 and references therein.
K considering that C O is an important product of reaction 2. If we assume an early, tight, transition state for reaction 3 having the structure of furvalene, A S 3 is expected to be nearly zero since
Q furvalene
no new internal rotations are created. Accordingly we predict A3 = 2 x 1013.8= s-l and = A3 exp(-LP3/R) = s-I at 1100 K for furan. Here we have evaluated A$‘3 = 9.8 eu from reported data for furan SOllooK = 100.5 eu23and an estimated value of SOllmK (c-C3H3CHO) = 110.3 eu.l0 A one-parametr fit of the falloff data in Figure 1 by means of RRK unimolecular reaction theoryz4is consistent with the following high-pressure Arrhenius expressions: log ( k 3 ,s-l) = 14.1 - 68.5/8 (8 = 4.575 X 10-3T kcal/mol). From this and M ~ , I = ~mM f , 1 1) MK ) K (cC3H3CHO)- AHf,llmK(furan)= 40.0 + 11.7 = 51.7 k c a l / m 0 1 ’ ~ ~ ~ ~ we calculate E-3 = E3 - AH3 = 16.8 kcal/mol and log (k+ s-l) = 11.9 - 16.8/8. See Table I for the thermodynamic data. Reaction 4 produces rather rigid stabilized biradicals, A and B in Scheme I, possessing allylic and acetonylic-type resonances. We have chosen to depict one of the various valence-bond canonical structures in Scheme I to help visualize the ensuing H-atom transfers. Based on previous analysi~,’~ one can estimate a value S-I or furan and 2,5-dimethylfuran and a factor of of A4 = 2 smaller for 2-methylfuraq A4 = 1015.3s-I. Notice that rotational symmetry numbers and reaction path degeneracies for 2,4-DMF and 2,5-DMF are u = 1, l4 = 1 and u = 2, l4 = 2, respectively, and therefore u/14 = 1 in both cases. If we assume that reaction 4 is rate controlling, Le., kl = k4 and k , = k4 or k5 and k5,faster than k4, evaluation of the extent of falloff of the experimental data in Figure lZ4leads to the followng high-pressure Arrhenius expressions: log (kl,F, S-l) = 15.6 - 73.5/8 log (kl,MF, S-l) = 15.3 - 74.2/8 log (kZ,DMF,S-l) = 15.6 - 74.1 / 8 Clearly these parameters lend support to a common mechanism for the decomposition of the three furans and also to the contention that we are actually dealing with homogeneous gas-phase reactions since the differences in rates (Figure 1) can be largely accounted for by the variation in the number of active modes. The likely errors in the above parameters are a factor of 2 in A ivalues or & 2 kcal/mol in the E;s. The possibility that biradicals A and B can be directly reached by the opening of the cyclopropene ring, step 4’ not shown in Scheme I, can be discarded. From experimental studies on the cyclopropene pyrolysis A4, can be estimated as 1013.4s-l at 1100 K.21 The largest possible value of E4, would attain if k-3 > k4/, Le., kl = K3k4/.Using A P 3 , l I o o and A: we get E l = 73.6 and E4/ = E l - AH3 = 21.8 kcal/mol, a value considerably smaller than 38 kcal/mol, the reported activation energy for the ring (23) Guthrie, Jr., G. B.; Scott, D. W.; Hubbard, W. N.; Katz, C.; McCullough, J. P.; Gross, M. E., Williamson, K. D.; Waddington, G. J. Am. Chem. Soc. 1952, 7 4 , 4662. (24) Golden, D. M.; Solly, R. K.; Benson, S. W. J . Phys. Chem. 1971, 75, 1333.
(25) O’Neal, H. E.; Benson, S. W. J. Phys. Chem. 1968, 72, 1866.
J . Phys. Chem. 1985,89, 41-44 opening of cyclopropene.21 The lowering of this value by about 8-1 0 kcal/mol to account for the effect of the carbonyl group attached to the ring (see below) would not remove the discrepancy. The same argument places a considerable barrier for the closure of biradical A to a cyclopropene ring. Biradical A necessarily has a smaller heat of formation than the transition state of reaction 4 which is given by (AHf,furan E,). In other words there is a finite barrier to ring closure, E-4 > 0, since E , E2 although E5 is probably larger than E(. This follows from the fact that no alcohol is detected in the decomposition of 2-methylfuran where both shifts might conceivably take place. In the case of furan this argument leads to AHf(A) I63 kcal/mol at 1100 K. This value should be compared with estimates based on standard methods.1° Starting with buten-3-a1 (CH2=CHCH2CHO), = -18.1 kcal/mol, assuming BDE (C2-H) = 82 kcal/mol, BDE (C,-H) = 108 kcal/mo1,26 and considering the acetonyl-type resonance (-2 kcal/mol)l' leading to the structure of biradical A depicted in Scheme I (CH=CHCH=CHO), we arrive at AHf(A) 1 63 kcal/mol at 1100 K, in excellent agreement with
+
-
(26) The value of BDE(C2-H) = 82 kcal/mol is arrived at by assuming that a normal R2C(H)-H bond (BDE = 94 kcal/mol) is stabilized by allylic resonance ( E , = 12 kcal/mol). BDE(C,-H) corresponds to the BDE(viny1H)."
41
the value derived above from present kinetic data. Thus, although it may be argued that this value actually represents a lower limit to M d A ) since allylic resonance in this species involves a carbene: :CH-CH=CH-CHO and is either forbidden27or not fully developed, we conclude that the biradical mechanism for the thermal decomposition of the furan ring presented in Scheme I is entirely consistent with available kinetic and thermochemical evidence. It should be emphasized that ring breakdown seems to represent a low-energy reaction pathway for furans in contrast with the exceptional stability of pyridines.'a2* In fact it can be expected that slow but irreversible modification of coal structure would result above 450 OC as a consequence of the destruction of furan units. On the other hand, their presence indicates that fossilization of biomass over geological times could not have occurred at temperatures far above 300 OC. Further studies are underway.
Acknowledgment. This work was supported with grants from CIC, SUBCYT, and CONICET of Argentina. Mr. E. F. Valla provided valuable technical assistance. Registry No. F, 110-00-9; MF, 534-22-5; DMF, 625-86-5. (27) Davis, J. H.; Goddard 111, W. A.; Bergman, R. G. J . Am. Chem. SOC. 1976, 98, 4015.
(28) Barton, B. D.; Stein, S. E. J . Chem. Soc., Faraday Trans. I 1981, 77, 1755.
Fluorescence Probe Studies of the Interactions between Poly(oxyethy1ene) and Surfactant Micelles and Microemulsion Droplets in Aqueous Solutions Raoul Zana,* Panagiotis Lianos,*and Jacques Langt Centre de Recherches sur les Macromol&cules, Greco Microemulsion, 67000, Strasbourg, France, and Department of Physics, University of Crete, Heraklion, Greece (Received: June 26, 1984)
The interaction between poly(ethy1ene oxide) (POE) and the aggregates present in micellar solutions of sodium dodecyl sulfate (SDS), mixed micellar solutions of SDS + 1-pentanol, and oil in water microemulsions made of SDS + 1-pentanol + oil (dodecane or toluene) has been investigated by means of fluorescence probing methods. It is shown that the addition of POE results in a decrease of the aggregation number of SDS in the aggregates present in all the systems investigated. Most likely this decrease is due to the adsorption of the POE chain in the micelle palisade layer and the ensuing increase of micelle ionization.
Introduction The study of the interaction between water-soluble polymers and surfactants in aqueous solutions is interesting from both the fundamental and applied point of views. From the fundamental point of view polymer-surfactant interactions may result in changes of conformation of polymer chains.' The unfolding of globular proteins in the presence of surfactants is partly due to such interactions. On the other hand, the addition of polymers to micellar solutions of surfactants may modify the micellar properties, if interactions occur between polymer chains and surfactant m i ~ e l l e s . ~ J From the applied point of view, a better understanding of polymer-surfactant interactions may help in the formulation of the polymersurfactant systems used in enhanced oil recovery by surfactant flooding4 Polymer-surfactant interactions play also an extremely important role in detergency, where the antiredeposition agents, used to improve the detergency by avoiding the Centre de Recherches sur les MacromolEcules. *Department of Physics, University of Crete.
0022-365418512089-0041$01.50/0
soil redeposition during the rinsing cycle, are water-soluble
polymer^.^ Many of the studies dealing with polymer-surfactant interactions have focused on the thermodynamics of these interactions and/or the stoichiometry and nature of the surfactant-polymer c o m p l e x e ~ . ~ , ~The * ~ -studies ~ ~ have shown that in the sodium (1) Isemura, T.; Imanashi, A. J . Polym. Sci. 1958, 33, 337. Takagi, T.; Tsujii, K.; Shirahama, K. J . Biochem. 1975, 77, 339. Satake, I.; Yang, J . Biopolymers 1976, 15, 2263. (2) Cabane, B. J . Phys. Chem. 1977, 81, 1639 and references therein. (3) Kresheck, G.; Hargraves, W. J. Colloid InferfaceSei. 1981,83, 1 and references therein. (4) See: "Surface Phenomena in Enhanced Oil Recovery"; Shah, D. O., Ed.; Plenum Press: New York, 1981. (5) Cahn, A,; Lynn, J. In "Encyclopedia of Technical Technology"; Wiley-Interscience: New York, 1983; p 332. (6) Sasaki, T.; Kushima, K.; Matsuda, M.; Suzuki, H. Bull. Chem. SOC. Jpn. 1980, 53, 1864. ( 7 ) Fishman, M.; Eirich, F. J . Phys. Chem. 1971, 75, 3135; 1975, 79, 2740. (8) Gilanyi, T.;Wolfram, E. Colloids Surf. 1981, 3, 181; Magy. Kem. Foly. 1982, 88, 508.
0 1985 American Chemical Society
