1174
VERNONA. ZEITLER AND CHARLES A. BROWN
Vol. 61
initially spherical droplet is then zero because alter- so Rb would also be very nearly unity. Because of ing the shape produces no change in the internal the limited precision of their data, it was not possifield. More generally, if R = 1, there is no tend- ble to. ascertain which of the reported experimental ency for either a change of shape, or of orientation values might correspond to R, and which to Rb,so of a body of arbitrary shape, because the internal a quantitative interpretation of those results has field and therefore the electrostatic energy is inde- not been attempted. It seems possible that refinependent of shape and orientation. It is interesting ment of Buchner and van Royen’s techniques and that this may be true in the presence of surface application of the above theory might lead to dicharges. It can be shown easily that in the steady electric constant values in conducting systems at state the surface charge vanishes when e l / ~ l = frequencies too low for practicable measurement by conventional methods. B ~ / K Z . Thus, for R = 1, surface charges will be present except in the special instance, €1 = €2. E. Oblate Spheroids.-In certain instances, Condition (b) is of particular interest. If it is it can be seen that the droplet will be compressed found that e = 0 when R # 1, the ratio of dielectric along the direction of the field. The required constants may be calculated from the ratio of con- conditions are ductivities with the aid of equation 12b. It is well R > 1; R2 7R - 2 C 6ez/ei (13a) known that low frequency dielectric constants of or conducting media are difficult to measure by conR < 1; R2 7 R - 2 > 6 ~ / r i (13b) ventional methods. On the other hand, conducThis type of deformation was reported by Buchner tivities can be determined relatively accurately. Thus, the possibility arises that low frequency di- and van RoyerP for iron oxide and vanadium pentelectric constant ratios may be determined in rela- oxide sols in aqueous solutions of higher conductivtively highly conducting systems by application of ity. Again, their results cannot be interpreted equation 12b, after experimentally determining the quantitatively, but it can be inferred that the‘dielectric constants of the sols at the frequency they conductivity ratio, R b . Some years ago Buchner and van Royeng studied employed (presumably that of their power mains) the movement of liquid streams and drops in an were less than the aqueous solution values. Accordelectric field. In the course of their studies, drop- ing to equation 11, it should have been possible lets consisting ,of a dilute (0.025%) aqueous solu- to cause a spreading of the droplets, which was obtion of crystal violet, an aqueous silver sol, and an served for lower medium conductivities, by increasarsenic trisulfide sol, were observed under the influ- ing the conductivity of the medium, or decreasing ence of d.c. and low frequency alternating fields in R still further. Apparently, no attempt was made aqueous solutions of various electrolytes. The to do this. Deformation of droplets to oblate spheroids was electrolyte concentrations were adjusted to give zero deformations, and the corresponding resist- R Is0 observed by Bungenberg de Jong and Hoskamg ances (in a cell of unspecified geometry) of the in complex coacervates. Subsequently, de Ruiter droplet material and the surrounding electrolyte and Bungenberg de Jonglo employed the phenomesolutions were reported. The resistances of the non to study qualitatively the interfacial tensions surrounding solutions were always within a few per between coacervate droplets and the liquid phase cent. of the droplet material, and a single resistance in gelatin-gum arabic coacervates. The above value was reported for zero deformation with each treatment constitutes a theory of this effect. electrolyte solution. The existence of two values (9) H. G. Bungenberg de Jong and E. G. Hoskam, Ronikl. Ned. evidently was not detected. For the dilute solutions Akad. Wetenschap. Proc., 44, 1099 (1941); H. G. Bungenberg de Jong, of crystal violet, e2/e1 would be very nearly unity, Ch. 10 in “Colloid Science,” Vol. 11, ed. by H. R. Kruyt, Elsevier Pub,
+ +
(8) E. H.Buchner and A. H. H. van Royen, Rolloid Z., 49, 249 (1929). I
Co., Ameterdam, 1949, (10) L. de Ruiter and H. G. Bungenberg de Jong, Roninkl. Ned. Akad. wetenechap. Proc., 60, 836 (1947).
THE INFRARED SPECTRA OF SOME Ti-0-Si, Ti-0-Ti AND Si-0-Si COMPOUNDS1 BY VERNONA. ZEITLERAND CHARLES A. BROWN^ Contribution from the Department of Chemistry, Western Reserve University, Cleveland 6, Ohio Received March 19, 1967
The infrared spectra of tetrakistriphenylsiloxytitanium, tetrakistrimethylsiloxytitanium, tetrakistriphenylsiloxysilane, tetrabutoxy- and tetraisopropoxy-titanium a condensed butoxy-titanium ester, and Ti[O&i,( CeH&]n are reported. Assignments are made for the Ti-0-Si and Ti-&Ti bonds.
Introduction During the previously reported8 inyestigations of ( I ) Taken from the thesis of V. A. Zeitler, submitted in partial fulfillment of the requirements for the Ph.D. degree, 1956. (2) Advance Development Laboratory, Lamp Wire and Phorphors Pep@r$pent,General Electric Company, Cleveland 10, Ohio.
titanium-oxvgen-silicon and titanium-oxvzen-titanium compounds, an extended series of jgfrared spectra were obtained. Review of the literature indicated that spectra of these types of compounds “ V
(3) (a) V. A. Zeitler and C. A. Brown, J . Amer. Chem. Sac., 79, 4616 (1957); (b) ibid., 79, 4618 (1957).
-
Sept., 1957
INFRARED SPECTRA OF SOME TITANIUM-OXYGENSILICON COMPOUNDS
have not been reported. Surprisingly enough, even the spectra of the simple titanium esters are not available. Fortunately, rather complete assignments of the absorption peaks have been made. In addition, the absorption peaks for Ti-0-Si bonds and Ti-OTi bonds are first reported. The infrared spectra of Ti[O5Si4(C6H5)8]2 was of value in the selection of the probable structure of this unusual compound. Experimental Infrared spectra were obtained on either a Perkin-Elmer single-beam, doubIe-pass Infrared Spectrometer, modified model 12-C with an electronic slit drive, or on a PerkinElmer double-beam Model 21 instrument. I n instances where the solubility of the compound was too low for determination of the spectrum in solution, a mixture of the compound and potassium bromide was compressed at 20,000 p.s.i. and the spectrum compared with that of a potassium bromide blank. For solution studies, 0.1 mm. sodium chloride cells were used. The preparation of the compounds has been reported previously.3 All substances were purified carefully by methods described with their preparation. Tetrakistriphenylsiloxytitanium, [ ( C6H5)sSiO]4Ti.-Early attempts to secure the spectrum of tetrakistriphenylsiloxytitanium in carbon disulfide and in Nujol mulls were unsuccessful. Suspension in potassium bromide proved very effective, with concentrations of 0.25 and 0.12% necessary to give complete resolution of the strongest peak (925 cm.-l). The assignments are given in Table I.
1175
Tetrakistrimethylsiloxytitanium, [ (CH&SiO] rTi.-The spectrum of tetrakistrimethylsiloxytitanium was run at concentrations of 2.5 and 0.62% in carbon disulfide. The infrared spectrum of this compound was measured on the double-beam instrument. Assignments are given in Table 11. Tetraisopropoxytitanium, (i-CsH,O)4Ti.-The infrared spectrum of freshly distilled tetraisopro oxytitanium a t 2% in carbon disulfide was run on the singg-beam instrument. The results are given in Table 111. ' TABLE I11 INFRARED SPECTRUMOF TETRAISOPROPOXYTITANIUM
Wave no. cm.-1
Strength
2907 S 2817 m 1470 m 1391 m 1377 m 1344 m 1170 W 1131 vs 1006 VS 851 S See a of Table I.
Interpretation
Ref. page no."
Assym. stretch CH8 Sym. stretch CH3 Assym. C-H deform. Resonance split C-H Sym. C-H deform. Resonance splitting C-H (CH3)2CH-skeletal(l170) C-0 stretch and YS skeletal
16 15 19 23 20 23 25 25
Skeletal vib
25
p4
(850 cm.-l)
(I
Tetrabutoxytitanium, (n-C4H~O)4Ti.-The infrared spectrum of tetrabutoxytitanium in carbon disulfide was obtained on both Perkin-Elmer Spectrometers. See Table IV for the spectrum obtained on the double-beam instrument for a 1.6% solution.
TABLE I INFRARED SPECTRUMOF TETRAKISTRIPHENYLSILOXYTITATABLE IV NIUM INFRARED SPECTRUM OF TETRABUTOXYTITANIUM
Wave no., Strength cm. - 1
Interpretation
Ref. page no."
56 m =C-H stretch near 3030 281 m C=C ring stretch 281 w C=C ring stretch s Si-CeHs (in solid) 277-81 m vs Si-C& 281 m Si-C.dh 281 m Si-Cdh 281 m Si-C& 281 vs Ti-0-Si m Bending vib. C-H 277 m Bending vib. C-H 277 s Out-of-plane def. C-H 65 s Out-of-plane def. C-H 65 0 L. J. Bellamy, "The Infrared Spectra of Complex Molecules," John Wiley and Sons, Inc., New York, N . Y., 1954. 3000 1582 1497 1445 1274 1126 1072 1030 1004 926 747 737 712 697
TABLE I1
Wave no., orn.-I
2971 2944 2890 1460 1372 1295 1222 1124 1083 1034 987 967 899 863 746
Strength
s
Interpretation
Assym. CH3 stretch CHZstretch in phase s Sym. CHa stretch s Assym. C-H deform. m Sym. C-H bending w CH2 wagging (near 1300) w CHZwagging s I n C ~ H Q Oat H 1112 vs I n C4HQOH at 1072 s I n 4HQ0H at 1031 I n CIHQOHat 990 .w m I n C4HQOH at 952 w In CIHQOHat 904 m In C ~ H Q O at H 846 w CHI(CH2)3-0-( 634-742 cm.-') " See a of Table I. S. E. Wiberley and L. G. A n d . Chern., 22,841 (1950). s
Ref. page no.
16" 16-17" 15" 19" 20" 27" 27"
84Ib
Bassett,
INFRARED SPECTRUMOF TETRAKISTRIMETHYLSILOXYTITACondensed Butoxytitanium. Composition: [TiOl.aaNIUM
Wave no., cm.-'
Strength
8 2959 m 2907 m 1451 1401 m 1330 W 1248 VS 1057 m 919 vs 844 vs 751 s 687 m a See a of Table I.
Interpretation
CHa stretch CHI stretch Assym. C-H bending Sym. C-H bending C-H deform. near 1340 Si-(CH& rocking Si-0 Ti-0-Si Si-( CH& stretch Si-( CH& vibration
Ref. page no."
13 13 13 20 13 13 274 274 274
(OC4HQ)l.83] -'a.s.-The spectrum was measured for a 1.6% solution of this condensed ester in carbon disulfide by means of the Model 21 instrument. Assignments are given in Table V. Tetrakistriphenylsiloxysilane, [ ( CaH6)3Si0I4Si.-The infrared spectrum of tetrakistriphenylsiloxysilanewas determined in carbon disulfide on the double-beam instrument. Due to the low solubility of the silane in this solvent, a saturated solution ( < l % )was used. The results are given in Table VI where comparison is made with the spectrum of a 1.6% solution of hexaphenyldisiloxane in CSz. 16-Phenyloctasiloxyspiro[9.9] titanate, Ti[05S~(CEHa)8]2. -The infrared spectrum of Ti[OsSir(C6H&]2 was measured on the double-beam instrument. Two carbon disulfide solutions, one containing 2% of the opaque crystals from the original reaction and the other containing 2% of the colorless plates recrystallized from ether were measured. The peaks of the spectra were identical in position and in
1176
VERNON A. ZEITLERAND CHARLES A. BROWN
TABLEI V INFRARED SPECTRUM OF CONDENSED BUTOXYTITANIUM
Vol. 61
Discussion
The spectrum of tetrakistriphenylsiloxytitanium Wave no., Ref. shows an absorption peak at 926 cm.-'. This peak om. -1 Strength Interpretation page no. is not present in either the spectrum of triphenylsil2966 5 Assym. CHs stretch 16" anol or tetrabutoxytitanium. Similar peaks are 2865 m Sym. CHI stretch 17" observed a t 919 cm.-l in the spectrum of tetrakis1445 m Assym. C-H bending 19" trimethylsiloxytitanium and a t 925 cm. -l in the 1374 m Sym.C-H bending 20" spectrum of Ti[O&3i4(C6H6)8l2.It appears that this 1295 W CH2 wagging 27" peak probably is the stretch vibration of the Ti-O1224 W CH2 wagging 27" Si bond. The presence of methyl groups in place 1130 VS In Ti(OC4H& at 1124 of phenyl groups may have caused the shift from 1099 8 3 In Ti(OCaH& a t 1083 925 to 919 cm.-l. 1036 m In Ti(OC4H& at 1034 For tetrakistriphenylsiloxysilane, the absorp972 m In Ti(0C4H& a t 967 tion peaks correspond very closely to those of hexa899 W In Ti(OC4H& at 899 phenyldisiloxane. The peaks of these two spec866 m I n Ti(OC4H& a t 863 tra differ more in intensity than they do in wave 820 5 Ti-O-Ti length. The 1082 and 1078 cm. peaks are attrib763 m Ti-&Ti uted to the Si-O-Si stretch vibration. In the 744 m CHa(CHdr0841' a See a of Table I. S. E. Wiberley and L. G. Bassett, silane, the 1082 peak is more intense than the 1078 peaks of the siloxane. The silane contains more SiAnal. Chem., 22,841 (1950). O-Si bonds per mole than does the siloxane. The peaks in the spectrum of tetraisopropoxyTABLE VI titanium differ by only a few wave numbers from INFRARED SPECTRA OF TETRAKISTRIPHENYLSILOXYSILANE those in the reported spectrum of 2-propanol. The AND HEXAPHENYLDISILOXANE bands associated with the OH group in 2-propanol TetrakistriphenylHex? henyldisiloxysilane SIPOxane (3367 and 952) are missing in the titanium comWave Wave pound. The 1006 cm.-' peak in tetraisopropoxyno., no., cm.-1 Strength am.-' Strength Interpretation titanium has no corresponding peak in 2-propanol. 3032 m a038 m =C-H stretch near 3030° Similarly the spectrum of tetrabutoxytitanium reW 2999 w =C-H stretch' 2978 sembles closely the spectrum of l-butanol. The 1424 m 1426 m Si-CnHsb OH peak at 3356 cm.-' in l-butanol does not ap1186 m 1185 w Si-C6Hab Ill6 0 1116 8 Si-CsH8 pear in the spectrum of the titanium compound. 1104 m 1106 e Si-0, Si-CaHP Some peaks of l-butanol appear to be slightly dis1082 8 1078 m Si-0-Sie placed in the spectrum of tetrabutoxytitanium and 1020 m 1025 m Si-CsHs, near 1O3lc in the spectrum of the related condensed butoxy 997 m 996 m Si-CeH8 740 m 736 8 C-H bending* ester of titanium. The 952 peak may be related 712 8 711 a Out-of-plane def. C-Hd to the 967 and 972 cm.-l peaks of the two titanium 697 8 697 B Out-of-&ne 700 * lod See a of Table I, p. 56. b Ref. a, p. 277. Ref. a, p. compounds. The 846 cm.-l peak of l-butanol may be related to the 863 and 866 cm.-' peaks in a simi281. Ref. a, p. 65. e C. W.Young, et al., THISJOURNAL, lar fashion. The 1072 and 1112 cm.-' peaks of 170,3762(1948). butanol are related to the 1083 and 1124 cm.-' intensity. The results of the determination of the colorless peaks of tetrabutoxytitanium and the 1099 and plates from ether are recorded in Table VII. Comparison is 1130 crn. -l peaks of the condensed butoxytitanium made with the reported infrared spectra for .octaphenylcompound. cyclotetrasiloxane and hexaphenylcyclotrisiloxane. In the spectrum of the condensed butoxy ester TABLE VI1 of titanium the absorption peaks at 1099, 1036 and INFRARED SPECTRA OF Ti [0&(CeH&l2 AND CYCLIC 972 cm.-l are much weaker than the corresponding peaks in the spectrum of tetrabutoxytitanium. DIPHENYLSILOXANES This is to be expected since the number of butoxy Octa. henyl HexaphenylTi [OsSiccycgtetra: cyclotrisilgroups has been reduced during the condensation (CsHdclr siloxane" oxane' Wave Wave Wave process. Two new peaks, 820 and 763 cm.-l, are no., T no., T no., T, observed. Neither pea,k is present in the spectrum om.-' 3 cm.-1 ./d cm.-l % Interpretation of the simple ester. Both peaks fall in a region =C-H stretchb 3041 83 3082 57 3087 60 C=C, phenylapc 1592 90 1689 69 1589 74 where rutile, TiOz, shows almost complete absorpSi-CsHhd 1422 68 1429 40 1429 45 tion. However, for rutile, the region of complete Si-CsHld 1180 85 1188 90 1188 90 absorption extends from approximately 900 cm. -' (CsHn)nSi, doublet" 1125 12 1125 23 1127 40 to a t least 667 cm.-'. The M-0-M absorption (CsHdZSi, doublet" 1117 22 1117 23 1116 40 .. .. Si-0-Si, tetramer" frequencies in this series of compounds appear to 1093 32 1079 22 ... . . . . . . 1066 36 .. .. .. .. fall in one general area. The absorption of Ti-OSi-CsH,"~C 1027 57 1028 60 1034 23 Si a t 926-919 cm.-l is in the same general area as Si-0-Si, trimera .. .. .. .. 1013 5 Si-CsHb"*C Si-04% (1080-1013 cm.-'), P-0-P (1030 cm.-'), 998 60 998 72 992 20 925 14 .. .. .. .. Ti-O-Si P-0-C at 950 cm.-', and Si-0-C (1090-1050 Diphenyl subst." 739 51 739 53 739 62 cm.-'). Consequently, the peaks a t 820 and 763 Diphenyl subat." 717 37 720 47 721 38 cm.-l are believed to be due to Ti-O-Ti bonds. 0913 27 696 as 696 as Diphenyl subat." 70, 3762 (1948). More definite assignments of these peaks are not C. W. Young, et aE., THIS JOURNAL, possible at the present time. Ref. b, p. 281. Ref. b, p. 277. D Bee a of Table I, p. 56.
.
0
.,
Sept., 1957
THEINTERACTION OF CARRAGEENIN WITH COUNTERIONS
FOPTi [O&3si(C,H6)&, the spectra of samples of the opaque crystals and the colorless plates crystallized from ether were identical. Neither the peaks belonging to butyl alcohol nor the peaks of tetrabutoxytitanium were detected in either sample. Three strong peaks at 739, 717 and 696 ern.-’ correspond in intensity and position to three peaks attributed by Young to diphenyl substitution in octaphenylcyclotetrasiloxane. Hexaphenylcyclotrisiloxane can be differentiated from octaphenylcyclotetrasiloxane by the intensity pattern of these three peaks. In addition, octaphenylcyclotetrasiloxane has a strong absorption a t 1079 cm.-’, but the siloxane trimer absorbs at 1013 cm.-’. These peaks
1177
are due to the Si-O-Si stretch vibrations. They are distinctive features of the two cyclosiloxanes. The spectrum of Ti [O&3si(C,H,)s]zhas a strong absorption doublet at 1093 and 1066 cm.-’, but no absorption in the vicinity of 1013 cm.-’. This doublet corresponds to the 1079 cm.-l peak of octaphenylcyclotetrasiloxane. On the basis of this additional evidence, the colorless plates are believed to consist of molecules which contain two rings of four diphenylsiloxy groups, with each ring bonded through oxygen to the central titanium atom. We wish to acknowledge gratefully the financial assistance of the Office of Naval Research, during this investigation.
THE INTERACTION OF CARRAGEENIN WITH COUNTERIONS BY R. E. SCHACHAT AND H. MORAWETZ Contribution from the Central Laboratories, General Foods Company, Hoboken, N.J., and the Polymer Research Institute, Polytechnic Institute of Brooklyn, Brooklyn 1, Neu York Received April $8, 1067
The dialysis equilibrium of carrageenin solutions containing large concentrations of potassium, ammonium, calcium, magnesium or ethylenediammonium was investigated. The polymer solutions gave no evidence of a selective affinity for potassium over sodium. Magnesium was held in the olymer phase more strongly than calcium; the data for ammonium and ethylenediammonium are inconclusive. The resuLs indicate that counterion binding to isolated carrageenin molecules does not correlate with the ability to induce gel formation.
Introduction Carrageenin, an acidic polysaccharide with halfester sulfate groups, is a constituent of the alga Chondrus crispus and has long been known to be precipitable by potassium salts, while it remains in solution in the presence of similar concentrations of sodium.’ Smith and Cook2 have demonstrated that precipitation by potassium ion may be utilized to separate the natural product into two fractions, the potassium sensitive fraction (“K-fraction”) constituting about 40 weight % of carrageenin. More recently, Smith, O’Neill and Perlin have reported an interesting chemical difference between the two carrageenin fractions.8 They found that the K-fraction contains 24% of 3,6-anhydrogalactose units, which were almost completely absent in the portion of carrageenin which remains in solution in the presence of potassium ion. The difference in the behavior of the K-fraction toward sodium and potassium ion is in striking contrast to the stronger tendency of Na+ to participate in complex ion formation4-6 The clarification of the physico-chemical basis of the “potassium sensitivity” of carrageenin is particularly interesting in view of the many instances in which selectivity in the response to Na+ and K+ is a factor governing biological phenomena. The present
study was undertaken to show whether selective complex formation of potassium with carrageenin solutions may be demonstrated by dialysis equilibrium. The precipitation or gelation of carrageenin in the presence of divalent cations is less surprising, since many natural or synthetic polymeric acids behave in an analogous fashion. However, even here dialysis equilibrium data were expected to illuminate the nature of the ion-polyelectrolyte interaction.
Experimental
Carrageenin .-The carrageenin was Viscarin (Algin Co., Rockland, Me.). Its moisture content was determined by drying to constaiit weight a t 70” at a pressure of 100 mm. The intrinsic viscosity in 0.2 N NaCl a t 25” was 0.2 dl./g. The potassium sensitive fraction (K-fraction) was determined by precipitating three times a sample of 4 g. (on a dry basis) dissolved in 2 liters of water, once with 700 ml. and twice with 400 ml. of 1 N KCI. The salt solution was run in with stirring and the stirring was continued for 30 minutes before separating the precipitate by centrifugation. The last supernatant gave no precipitate on mixing with a double volume of isopropyl alcohol, indicating the absence of carrageenin. The slurry of potassium carrageenate was washed repeatedly with isopropyl alcohol until the su ernatant was free of chloride. The slurry was then filteref onto a tared fritted glass funnel, dehydrated with isopropyl alcohol and vacuum dried at 70’ for 7 hours. The yield was 59.47& The fraction of carrageenin not pre(1) L. Stoloff, in “Natural Plant Hydrocolloids.” American Chemicipitated by potassium chloride was precipitated from the combined supernatants by mixing with two volumes of cal Society, 1954, p. 92. isopropyl alcohol. It constituted 36% of the original (2) D. B. Smith and W. H. Cook, Arch. Biochsm. Biophye., 48, 232 Sam le. (1953). Tge original Viscarin contained considerable amounts of (3) E?. B. Smith, A. N. O’Neill and A. 8. Perlin, Can. J . Chem., 33, 1352 (1955). potassium and alkaline earths and it was purified by 9 batch(4) G. Schwarsenbach, E. Kampitach and R. Steiner, Helv. Chim. wise treatments with the cation exchanger IR-120 (Rohm A d o , 29, 364 (1946). and Haas) in the sodium form. The final sample contain+, on !dry ba$s, 6.6% Na, 0.018% K and lO.l% S. (6) G. Sahwaraenbsch and H. Ackermann, ibid., 80, 1788 (1947). The intrinsic viscosity was 7.2 dl./g. This purified Vis(6) W. C. Fernelius and L. G. VanUitert, Acta Chsm. Scand., I, 1726 carin (sodium carrageenate) was used in all the experiments. (1954).
