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The permeation of electrolytic hydrogen through lead1

IVAN ~ADERSK?, BANSI L. MUJU, AND FRANK R. SMITH^ Cl~enzistry Department, Memorial University of Newfoundland, St. John's, Newfoundland

Received February 12, 1970

Conclusive evidence is reported for the permeation of electrolytic hydrogen through lead. The diffusion coefficient at 25 "C lies between and cmZ s-' while the bulk concentration of dissolved hydro- gen is indicated to be g-atom cm-3 at current densities of 10 to 50 mA cm-'.

Canadian Journal of Chemistry, 48, 1789 (1970)

Smith (1) in 1948 concluded that hydrogen diffusion through lead occurs only at tempera- tures close to the melting point, the earlier evidence3 for diffusion of hydrogen produced by electrolysis being considered too slender to accept. More recently Heath (2) and Wahlin and Naumann (3) both failed to observe electrolytic permeation through lead.

Electrolytic permeation currents of 0.5 to 5 pA cm-2 have been observed using lead foils cathodized in hydrogen (Matheson prepurified, BASF-BTS catalyst-treated) stirred 1 M HCIO, (Reagent Grade, plus 3 x distilled water) at 10 to 100 mA ~ m - ~ , on one side and potentiostatted in hydrogen-saturated 0.2 M KOH (Reagent Grade, plus 3 x distilled water) at +200 mV vs. a hydrogen electrode, also in 0.2 M KOH. Fisher lead (L27, ca. 99 % pure) and Goodfellow Metals (99.9 % pure) lead gave comparable results when degreased in boiling benzene, chemically polished in 60% HC10, and washed with 3 x distilled water before use. Cathodic protection currents of 30 pA cm-2 applied to the cathode side were without effect on the diffusion side, where background anodic currents were ca. 1 pA cm-'.

Figure 1 shows typical data plotted according to Devanathan and Stachurski (4) with the experimental points lying on reasonably straight lines which for 10 and 25 mA have the theoretical intercept of log,, 2 at t = 0. The

'This research was supported, in part, by the Defence Research Board of Canada, Grant number 5401/09.

'To whom correspondence should be addressed. 3References 906, 1091, 1092, 1266, 1268, and 1269

cited in ref. 1.

diffusion coefficients DH may be calculated from the experimental slopes (4).

An improved method of treating the data is due to McBreen, Nanis, and Beck (5). A theoret- ical curve for the ratio of flux, J, , at time t to the steady state flux, J,, was derived by Laplace transformation with appropriate boundary con- ditions. The first-order approximation is

where z is the dimensionless parameter D~/L', L being the foil thickness. This curve, plotted in Fig. 2, and the experimental curves should be of identical shape up to JJJ, z 0.95, ifthe boundary conditions are applicable. D is then calculable from the z and t values appropriate to the chosen value of JJJ,. Experimental curves for 10 and 25 mA conform to expectations for JJJ, > 0.2, whereas those for 2 50 mA cmP2 are anom- alous. Calculated diffusion coefficients for atomic hydrogen in 99.9% pure polycrystalline lead at 25 5 2 "C are given in Table 1.

Agreement is good between the calculated

TABLE 1 Diffusion coefficient for H in lead at 25 "C

DH x lo7 (cmZ s- l )

Fig. 2 t for JJJ, = 2eathodle

(mA cm-') Fig. l * 0 .2 0.3 0 .5 0.8

*L = 0.15 mm, DM = 2.3L1KIn1. t L = 0.15 mrn, DH = rLZ/t.

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CANADIAN JOURNAL OF CHEMISTRY. VOL. 48, 1970

t (5) FIG. 1. Successive permeation transients in cathodization at 10 mA cm-2 (circles), 25 mA (crosses), and 50

mA cm-2 (triangles), plotted according to Devanathan and Stachurski (4). J, , J , are anodic current densities ( P A cm-') above background, at time t after application of cathodic current and at steady state, respectively. Transients observed on one foil in order 1, 2, 3 with ca. 15 min at 30 pA ~ m - ~ between cathodization. K's are best straight line slopes.

FIG. 2. Rising transients of Fig. 1 treated according to McBreen, Nanis, and Beck (5). J , and J , as in Fig. 1. Numbers refer to Fig. 1 except 4 which is the theoretical curve of eq. [I].

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COMMUNICATIONS 1791

values at 10 and 25 mA cmP2 but DH apparently Thanks are due to the National Research Council of

depends on the applied current, presumably Canada and to the Defence Research Board for their

because of a dependence on the bulk concentra-

of in the (ca. g-atom I . D. P. SMITH. Hydrogen in metals, Univ. of Chicago cmP3). Gileadi, Fullenwider, and Bockris (6) Press. Chicago, 111. 1948. p. 286. observed an increasing D, in successive permea- 2. H. R. HEATH. Brit. J. APP~. Phys. 3,13 (1952).

3. H. B. WAHLIN and V. 0. NAUMANN. J. Appl. Phys. tions through platinum. Their suggestion of 24,42 (1953). hydrogen concentrated in regions of strain being 4. M. A. V. DEVANATHAN and Z. 0. J. STACHURSKI.

Proc. Roy. Soc. London, Ser. A, 270, 90 (1962). less free to diffuse may here 5. J. MCBREEN, L. NANIS, and W. BECK. J. Electro-

the formula PbHo.ooooz differs by of chem. SOC. 113, 1218 (1966). magnitude from Wells and Roberts' PbH,.,, 6. E. GILEADI, M. A. FULLENWIDER, and J. O'M.

BOCKRIS. J. Electrochem. Soc. 113, 926 (1966). achieved exposure of lead 'lms 7. B. R. WELLS and M. W. ROBERTS. Proc. Chem. to atomic hydrogen (7). Hence the lead is unlikely SOC. 173 (1964). to have become saturated in the present work.

Total synthesis of DL-glucose

U. P. SINGH' AND R. K. BROWN Department of Cf~emistry, University of Alberta, Edmonton, Alberta

Received February 20, 1970

The stereoselective synthesis of DL-glucose has been accomplished in 34% overall yield starting from 1,6:2,3-dianhydro-4-dexoy-[3-~~-ribo-hexopyranose (I), a compound obtainable from the Diels-Alder condensation of acrolein. Canadian Journal of Chemistry, 48, 1791 (1970)

The compound 1,6:2,3-dianhydro-4-deoxy-P- lithium at room temperature following the known DL-ribo-hexopyranose (I), obtained from acro- reaction of oxiranes with the organolithium lein dimer according to published directions (I), reagent (2). Treatment of 2 with m-chloroperoxy- was converted into 1,6-anhydro-3,4-dideoxy-P- benzoic acid in methylene chloride at room DL-erythro-hex-3-enopyranose (2) with n-butyl- temperature for 24 h gave the expected 1,6:3,4-

'Postdoctoral Fellow 1969-1971.

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