Table 1 Electrochemical methoxylation of organic compounds with-
out supporting electrolytea
J. Membr. Sci, 1987, 30, 23; (h) Z. Ogumi, S. Ohashi and Z. Takehara,
Electrochim. Acta, 1985, 30, 121; (i) Z. Ogumi, K. Nishio and
Z. Yoshizawa, Electrochim. Acta, 1981, 26, 1779.
Starting
material
Current/
mA
Conversion/
%
Conversion
yield/%
2 For examples of flow and microflow electrochemical reactors, see: (a)
J. Heo, K. J. Thomas, G. H. Seong and R. M. Crooks, Anal. Chem.,
2003, 75, 22; (b) W. Zhan, J. Alvarez and R. M. Crooks, Anal. Chem.,
2003, 75, 313; (c) W. Zhan, J. Alvarez, L. Sun and R. M. Crooks, Anal.
Chem., 2003, 75, 1233; (d) M. Ku¨pper, V. Hessel, H. Lo¨we, W. Stark,
J. Kinkel, M. Michel and H. Schmidt-Traub, Electrochim. Acta, 2003,
48, 2889; (e) W. Zhan and R. M. Crooks, J. Am. Chem. Soc., 2003, 125,
9934; (f) V. Mengeaud, O. Bagel, R. Ferrigno, H. H. Girault and
A. Haider, Lab. Chip, 2002, 2, 39; (g) J. Yoshida and S. Suga,
Chem. Eur. J., 2002, 8, 2650; (h) H. Ernst, B. Roß and M. Knoll,
Electrochim. Acta, 2002, 47, 1795; (i) S. Suga, M Okajima, K. Fujiwara
and J. Yoshida, J. Am. Chem. Soc., 2001, 123, 7941; (j) H. Lo¨we and
W. Ehrfeld, Electrochim. Acta, 1999, 44, 3679; (k) C. Karakus and
P. J. Zuman, J. Electrochem. Soc., 1995, 142, 4018.
Product
3
3
11
22
11
11
77
86
25
75
4 and 5
4 and 5
7
7
57 (4), 40b (5)
46 (4), 47b (5)
56b
6
6c
65b
a
b
c
Flow rate 2 mL h21
.
A mixture of cis and trans isomers. 50 uC.
3 C. A. Paddon, G. J. Pritchard, T. Thiemann and F. Marken,
Electrochem. Commun., 2002, 4, 825.
4 A textile carbon felt made from carbon fiber (ca. 60 mg, Nippon
Carbon JF-20-P7) was used as electrode. This carbon fiber electrode was
dried before use by heating at 250 uC for 2 h.
5 BASF Information 15.10.98, company brochure, BASF, Ludwigshafen.
6 The cell voltage and the feature of the reaction strongly depend on the
purity of methanol solvent. Throughout this study dried and distilled
methanol (water content ,70 ppm) was used. The use of methanol
containing higher than 300 ppm of water gave rise to much higher cell
voltage and lower conversion of the starting material. The use of
methanol dried over molecular sieves without distillation resulted in
lower cell voltage in the case where thicker spacer was used. Presumably,
a small amount of impurities, which dissolved into methanol from
molecular sieves are responsible for better conductivity. More data,
however, should be accumulated before elucidation of the detailed
explanations of these observations.
The authors are grateful to a Grant-in-aid for Scientific
Research and the Project of Micro Chemical Technology for
Production, Analysis and Measurement Systems of NEDO for
partial financial support.
Roberto Horcajada, Masayuki Okajima, Seiji Suga and
Jun-ichi Yoshida*
Department of Synthetic Chemistry and Biological Chemistry, Graduate
School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510.
E-mail: yoshida@sbchem.kyoto-u.ac.jp; Fax: +81-75-383-2727;
Tel: +81-75-383-2726
Notes and references
7 The current efficiency under standard operating conditions was
36%.
8 No appreciable change in the resistance of the flow was observed when
two sheets of membrane were used as a spacer.
9 T. Shono, H. Hamaguchi and Y. Matsumura, J. Am. Chem. Soc., 1975,
97, 4264.
10 (a) Y. N. Ogibin, A. I. Ilovaiski and G. I. Nikishin, Electrochim. Acta,
1997, 42, 1933; (b) A. Guirado, F. Barba and F. A. Franco, Electrochim.
Acta, 1982, 27, 1621.
1 For examples of the use of SPE membranes in electroorganic chemistry,
see: (a) J. Jo¨rissen, J. Appl. Electrochem., 2003, 33, 969; (b) S. S. Vaghela,
G. Ramachandraiah, P. K. Ghosh and D. Vasudevan, J. Appl.
Electrochem., 2002, 32, 1189; (c) D. Hoormann, C. Kubon, J. Jo¨rissen,
L. Kro¨ner and H. Pu¨tter, J. Electroanal. Chem., 2001, 507, 215; (d)
J. Jo¨rissen, Electrochim. Acta, 1996, 41, 553; (e) Z. Ogumi, K. Inatomi,
J. T. Hinatsu and Z. Takehara, Electrochim. Acta, 1992, 37, 1295; (f)
Z. Ogumi, M. Inaba, S. Ohashi, M. Uchida and Z. Takehara,
Electrochim. Acta, 1988, 33, 365; (g) E. Raoult, J. Sarrazin and A. Tallec,
This journal is ß The Royal Society of Chemistry 2005
Chem. Commun., 2005, 1303–1305 | 1305