2178 Bull. Chem. Soc. Jpn., 74, No. 11 (2001)
Dimerization of Formic Acid by Ar-Arc Plasma
were maintained at 10 V and 10 A.
Analytical Method: In the analysis of the dimerization of
formic acid, formic was analyzed by a Dionex 2000i ion chro-
matograph equipped with a Dionex HPICE-AS1 column (250 mm
× 9 mm I.D.). Eluent: 0.125 mM octanesulfonic acid. Flow rate:
1.0 mL/min. Oxalic acid was analyzed using a capillary isotacho-
electrophoresis apparatus (Shimadzu IP-2A). Leading electrolyte
solution: 0.01 M hydrochloric acid containing 0.5% triton X-100
and β-alanine. Terminal electrolyte solution: 0.01 M hexanoic ac-
id. Capillary column: 100 mm × 0.5 mm I.D. Detector: electropo-
tential gradient detector at 20 °C.
The analyses of formic acid and oxalic acid formed in the
dimerization of sodium formate were carried out on an ion chro-
matograph equipped with a Dionex HPICE-AS1 (250 mm × 9
mm I.D.) column and a TSK gel IC-Anion-PW column (50 mm ×
4.6 mm I.D.), respectively. Eluent: 0.125 mM octanesulfonic acid
(for formic acid) and boric acid buffer solution (pH 8.5) (for oxal-
ic acid) which was composed of boric acid (360 mg), sodium tet-
raborate (500 mg), glycerol (5.0 g), potassium gluconate (300
mg), acetonitrile (120 mL), and 1-butanol (30 mL) in one liter of
solution. Flow rate: 1.0 mL/min in both analysis.
Fig. 8. Degradation of malonic acid, sodium malonate and
calcium malonate induced by Ar-arc plasma (10 V, 10 A).
ꢃ: Malonic acid (1.03 mmol/50 mL H2O), ꢅ: Sodium ma-
lonate (1.11 mmol/50mL H2O), ꢂ: Calcium malonate
(1.06 mmol/50 mL H2O).
Analyses of the reaction products obtained by dimerization of
calcium formate were carried out using a capillary column isota-
choelectrophoresis instrument. Leading electrolyte solution was
similar to the one mentioned above, except that the pH was 3.7.
In the dimerization reaction of formamide, the resulting oxam-
ide was analyzed by HPLC (JASCO Trirotar-V with a UV-Spec-
trophotometer UVIDEC-100-IV) at 215 nm, column ODS (250
mm × 4.6 mm I.D.), eluent liquid: H2O, flow rate 0.5 mL/min.
Formamide was analyzed by a gas chromatograph (Hitachi 163)
under the following conditions: column, (UNISOLE F-200 (2 m
× 3 mm I.D.) at 150°C; injection temp., 250°C; carrier gas, N2;
detector, FID (flame ionization detector).
References
1
a) J. R. Hollahan and A. T. Bell, “Techniques and Applica-
tions of Plasma Chemistry,” Wiley-Interscience Publication
(1974). b) M. A. Lieberman and A. J. Lichtenberg, “Principles of
Plasma Discharges and Materials Processing,” John Wiley &
Sons. Inc. (1994).
Fig. 9. Apparatus for Ar-arc plasma induced reaction in
aqueous solution.
2
A. Hickkling, “Modern Aspects of Electrochemistry,” ed
by J. O’M. Bockris and B. E. Cornway, Plenum Press (1971), Vol.
6, p. 329.
3
K. Harada and M. Nomoto, J. Syn. Org. Chem. Jpn., 40,
water, and calcium succinate was prepared by mixing sodium suc-
cinate and calcium chloride. Sodium oxalate, sodium acetate, cal-
cium acetate, sodium succinate, sodium malonate, and calcium
malonate solutions were prepared by neutralization of the corre-
sponding aqueous solutions of the organic acids with sodium hy-
droxide or calcium hydroxide.
Apparatus and Methods of Reactions : The apparatus used
for the dimerization reaction is shown in Fig. 9. The glass-made
apparatus was equipped with a condenser; cold water (0–5 °C)
was circulated at a flow rate of 19 L/min to prevent the rise of the
aqueous reaction mixture (25–30 °C). The reaction mixture (50
mL) was stirred by a magnetic stirrer. The argon torch (Nippon
Welding, WEL pen NP-7) was withdrawn at appropriate times,
and the samples were subjected to a gas chromatograph (Hitachi
163), an isotachoelectrophoresis instrument (Shimadzu IP-2A),
and an ion chromatograph (Dionex 2000i) to analyze the starting
material, dimerized product, and other products. During the Ar-
arc plasma reactions, the voltage and the current of the apparatus
368 (1982).
4
K. Harada, “Molecular Evolution and Protobiology,” ed by
K. Matsuno, K. Dose, K. Harada, and D. L. Rohlfing, Plenum
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K. Harada, J. Syn. Org. Chem. Jpn., 48, 522 (1990).
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K. Harada, J. Terasawa, and H. Gunnji, Chem. Lett., 1980,
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