862
F. K. BELL, C. J. CARR AND J. C. KRANTZ, JR.
SUGAR ALCOHOLS. XXI A STUDYOF
THE
EFFECT OF SOCIATION
THE ANHYDRIDES OF SORBITOL ON CONSTANT OF BORICACID
FREDERICK K . BELL, C. JELLEFF CARR,
AND
THE
DIS-
JOHN C. KRANTZ, JR.
Department of Pharmacology, School of Medicine, University of Maryland, Baltimore, Maryland Received November 2, 1989 INTRODUCTION
In a previous communication (4)two of the authors (C. J. C. and J. C. K., Jr.) with Oakley studied the effect of the anhydrides of mannitol upon the dissociation constant of boric acid. Later the extraordinary potentiation of the dissociation constant of boric acid produced by a-mannitan was reported (1). Since sorbitan and isosorbide, the mono- and di-anhydrides, respectively, of sorbitol, were available for metabolic study, it was decided to determine the effect of these two compounds upon the titration curve of boric acid and to compare this with the influence of sorbitol. MATERIALS AND METHOD
The boric acid was of buffer quality. The sorbitol was the C.P. compound generously supplied by the Atlas Powder Company of Wilmington, Delaware. Likewise the sorbitan was supplied by the Atlas Powder Company, which obtained it as a by-product in the electrolytic reduction of glucose. The recrystallized compound melted a t 112°C. Its specific rotation, CY]^^', was -24.5" (HzO; C = 10). The isosorbide was prepared for study by Dr. Wdton C. Harden of the fir-n of Hynson, Westcott, and Dunning of Baltimore. It was prepared by Fauconnier's method (2) of preparing isomannide from mannitol. The recrystallized compound melted a t 60°C. Its specific rotation, [a]$'was 46.5" (HzO; C = 10). The crystalline dibenzoate analyzed 101 per cent upon saponification. Solutions of the various compounds studied contained 4 g. of the compound in 100 cc. of 0.1 molar boric acid. Stronger concentrations were employed for conductivity measurements. To 1O-cc. portions of this was added 0.1 normal sodium hydroxide in quantities varying from 1 cc. to 11 cc. Immediately after the addition of the alkali the pH of the solution was determined electrometrically a t 25°C. f 0.5", using the Wilson type hydrogen electrode (6). The following formulas indicate the supposed structural relationship existing among the compounds.
+
SUGAR ALCOHOLS.
863
XXI
H*7-
CHzOH
I I
H-C-OH
I
HO-C-H
HO-C-H H-C--OH I
I I
H-C-OH
H-C-OH
~~
H-SOH CHzOH d-Sorbitol
H-C
0
I
‘1
I
H-C-OH
I
CHzOH 1,C-Anhydrosorbitol Sorbitan
II H-C-OH I
---&Ha 1,4,3,6-Dianhydrosorbitol Isosorbide
TABLE 1
Specific conductivities Aqueous solutions a t 25°C.; cell constant = 0.1417 M)LOTION
0P-C
CONDUCIIVITT
mhos
0 5
.u HJBOJ
30 5
x
10-6
The results of the pH measurements are set forth in figure 1. The specific conductivities of the polyol-boric acid complexes are shown in table 1. In figure 2 a comparison of the effect of dilution upon the sorbitan-boric acid complex and the corresponding a-mannitan complex is shown. DISCUSSION
The data in figure 1 show that the titration curve of the sorbitol-boric acid complex is practically the same as that previously reported for the two hexahydric alcohols mannitol and dulcitol. The curve for the isosorbideboric acid complex coincides with that obtained employing the isomannideboric acid complex. This suggests that there are not two hydroxyl groups linked to the same side of adjacent carbon atoms within the molecule and bespeaks a structure similar to that of isomannide, namely, 1,4,3,6dianhydrosorbitol. This assumption is further substantiated by the specific conductivity values of the isosorbide-boric acid complex of 43.3
864
F. K . BELL,
X mhos. ( 5 ) is 34.4 X
c.
J. CARR AND J.
c.
KRANTZ, JR.
The value obtained by van Romburgh and van der Berg mhos for the isomannide complex in the same concen-
trations. The titration curve of the sorbitan-boric acid complex shows approximately the same downward displacement as does the dulcitan-boric acid complex and not the strong displacement produced by the a-mannitanboric acid complex. This compound, therefore, does not possess the structure of the Fischer and Zach (3) crystalline sorbitan, which is the 3,6anhydrosorbitol with two hydroxyl groups linked to the same side of adjacent carbon atoms, similar to the a-mannitan structure. The degree
MOLLS WGAR ALCCXKIL IN 0 5 M H,SO,
hQ. 2 FIG.1. Effect of isosorbide, sorbitan, and sorbitol upon the dissociation constant of boric acid. Curve A, M / 1 0 boric acid 4 per cent of isosorbide; curve B, M/10 boric acid; curve C, M / 1 0 boric acid 4 per cent of sorbitan; curve D, M/10 boric acid + 4 per cent of sorbitol. FIG.2. Comparison of the effects of dilution upon the sorbitan- boric acid complex and the a-mannitan-boric acid complex. 0, a-mannitan; 0 , sorbitan.
+
+
of downward displacement of the titration curve and the conductivity measurements shown in figure 2 bespeak the 1,4-anhydrosorbitol structure for this compound, Le., an anhydride without two hydroxyl groups linked to the same side of adjacent carbon atoms. SUMMARY
1. The downward displacement of the titration curve of boric acid in the
presence of sorbitol, sorbitan, and isosorbide has been determined. Conductivity measurements are also included. 2. These data suggest a 1,4-anhydro structure for sorbitan and a 1,4,3,6anhydro structure for isosorbide.
865
DYE-SENSITIZED PHOTOOXID.4TIONS
REFEREKCES (1) BELL,K. K., CARR,C. J . , I':VANY,W. E., JR., AND I ~ R A N TJZ. ,C., J R . : J. Phys.
Chem. 4!2, 507 (1938). (2) FAUCONNIER, A , : Bull. soc. chim. 41, 119 (1884). (3) FISCHER, E., AND ZaCH, K.:Ber. 46,156 (1912). (4) KRANTZ, J. C., JR.,OAKLEY, M., A N D CARR,C. J . : J. Phys. Chem. 20, 151 (1936). (5) VAN ROMBURGH, G., AND V A N DER BERG,J. H. N . : Proc. Aead. Sci. Amsterdam 26, 335 (1922). (6) WILSON~ J . A . : Ind. Eng. Chem. 17, 71 (1925).
THE QUANTUhl YIELDS OF SOME DYE-SENSITIZED PHOTOOXIDATIONS FRANK HURD
~ N W ROBERT
LIVINGSTON
School of Chemzstry, Instztute of Technology, Cnzverszty of Minnesota, Mznnesota
11.i inneapnlis,
Recezved January 18, 1940
The photosensitization of oxidation-reduction reactions by dyes has been extensively studied. Since 1910 about fifty papers. have appeared on this or closely related subjects. However, relatively little quantitative work has been reported. This lack of quantitative information has seriously handicapped the establishment, upon a sound basis, of a theory or mechanism of these reactions, as is demonstrated by the fact that a t least four mutually inconsistent theories have been proposed in the recent literature. Since these reactions have important biological analogs and are not without intrinsic interest, it appeared t o the authors that they were worthy of a careful quantitative study from the physicochemical viewpoint. The present paper reports the results of a series of determinations of the quantum yields of photooxidations of several reducing agents sensitized by various dyes. The results of a detailed investigation of one of these systems,-solutions of eosin and potassium iodidej--will be published shortly. EXPERIMENTAL PROCEDURE
Materials a
The rose bengal, phenosafranine, and safranine T were Grubler preparations. The fluorescein was a Kahlbaum product. The neutral red was A product of the Xational Aniline and Chemical Company. The indigosulfonates and one sample of methylene blue were LaMotte indicators.
