Reduction of Salicylic Acid to Salicylaldehyde with Modulated Alternating Voltage

Abstract

The effect of superimposing sinusoidal, triangular, and square‐wave alternating voltage (aV) on the potentiostatic reduction of salicylic acid to salicylaldehyde has been studied. Polarization curves with aV modulation were measured with an amalgamated copper rotating disk electrode. Enhanced dc current densities were observed with increasing magnitude of superimposed aV. However, aV frequency and type did not have significant effect on the resulting dc current densities. Batch cell electrolysis experiments were conducted with a H‐type cell. The conversion of salicylic acid and yield of salicylaldehyde were measured as functions of electrolysis time, aV magnitude, type, and frequency. The superimposed aV significantly enhanced the reaction rate, conversion of salicylic acid, and the yield of salicylaldehyde. The energy consumption of ac electrolysis was higher than that of dc electrolysis.

Cathodic Corrosion of Metal Electrodes—How to Prevent It in Electroorganic Synthesis

“… 231 Amalgam or mercury-plated electrodes have been used also in preparative organic electroreductive synthesis. 34 , 42 , 153 , 210 , 231 − 236 For example, amalgamated copper, lead, and zinc were used to reduce vanillin to vanillyl alcohol, 232 amalgamated lead and copper in the adiponitrile synthesis, 42 amalgamated copper in the reduction of salicylic acid to salicylaldehyde, 234 mercury-plated copper in the synthesis of l -cysteine hydrochloride, 34 , 210 and amalgamated lead in the reduction of oxalic to glyoxylic acid ( Scheme 13 ). 235 …”

“…For example, dental amalgam electrodes are similar to silver electrodes but with a higher hydrogen overvoltage. − In another study, Pd, Au, Pt, and Cu amalgams behaved similarly than the pure Hg . Amalgam or mercury-plated electrodes have been used also in preparative organic electroreductive synthesis. ,,,,− For example, amalgamated copper, lead, and zinc were used to reduce vanillin to vanillyl alcohol, amalgamated lead and copper in the adiponitrile synthesis, amalgamated copper in the reduction of salicylic acid to salicylaldehyde, mercury-plated copper in the synthesis of l -cysteine hydrochloride, , and amalgamated lead in the reduction of oxalic to glyoxylic acid (Scheme ). …”

Oxygen Electro-Reduction on C22 and C276 Nickel Metal Alloy

“…The results shown in Figure 9 showing only one reduction onset current observed for reagent H 2 O 2 reduction in an Ar de-aerated environment, and the application of the ring collection coefficient accounting for 90% to 100% of the disc current due to H 2 O 2 formation, strongly indicates a series 2 step pathway for O 2 reduction on Alloys C22 and C276. The kinetic current can be obtained from the steady state disc data by calculating according to expression [1], where j L is the limiting current density and j is the current density. An estimate of the rate constant, k exp , for peroxide and water generation can be made by considering first the rate of O 2 electro-reduction reaction on Alloys C22 and C276 in alkaline media should have a first order dependence on O 2 concentration (9), expression [2], and second that the concentration of O 2 in aqueous 1M KOH equilibrated with 1 atmosphere of O 2 over solution is 2.2 x 10 4 moles per liter (10).…”

“…An estimate of the rate constant, k exp , for peroxide and water generation can be made by considering first the rate of O 2 electro-reduction reaction on Alloys C22 and C276 in alkaline media should have a first order dependence on O 2 concentration (9), expression [2], and second that the concentration of O 2 in aqueous 1M KOH equilibrated with 1 atmosphere of O 2 over solution is 2.2 x 10 4 moles per liter (10). The first wave of j kinetic = j L j/(j L -j) [1] j kinetic = k exp n[O 2 ] 1 [2] O 2 reduction on Alloys C22 and C276 between -0.6 to -1.0V vs. SCE goes to peroxide formation; an n value of 2 can be used along with the kinetic current determination from expression [1] to give k exp , which should be the same as k 2 in Figure 1, the rate constant for peroxide generation. The value of k 2 calculated in this way is roughly, 0.001 cm/s for C22 and 0.013 cm/s for C276.…”

Growth modulation and metabolic responses of Ganoderma boninense to salicylic acid stress

“…Coumarin (258.109 m/z) was another metabolite detected at significantly high concentration in G200 treatment (Fig 6A). Coumarin is synthesized via Perkin reaction or O-acetylation of salicylaldehyde, while reduction of SA yields salicylaldehyde [69][70][71]. In a recent study, treatment of SA at 10 mg mL -1 enhanced the production of bioactive constituents in fruiting bodies of G. lucidum, i.e., triterpenoids.…”