Micellar Catalysis on Quinquivalent Vanadium Oxidation of Methanol to Formaldehyde in aqueous medium

Pintu Sar1, Aniruddha Ghosh1, Debranjan Ghosh2 and Bidyut Saha1*

1Homogeneous Catalysis Laboratory, Department of Chemistry, The University of Burdwan, Golapbag, Burdwan, Pin 713104, WB, India.

2Department of Chemistry, Krishna Chandra College, Hetampur, Birbhum, WB 731124, India.

*Corresponding author, E-mail Id: (B. Saha) Mobile +91 9476341691, Tel: +91-342-2533913 (O), Fax: +91-342-2530452 (O)

Supplementary Data

Product analysis:

The reaction mixture having composition [Methanol]T = 1×10-2 mol dm-3, [vanadium(V)]T = 1×10-3 mol dm-3, [H2SO4]T = 3.0 mol dm-3 was oxidized at temperature 313 K. Methanol was mixed with the oxidant in aqueous acid medium under the usual kinetic condition. The reaction was then allowed to proceed for several hours. After two days, the reaction mixture was neutralized with sodium hydroxide and divided into two parts. One part was treated with chromotropic acid in sulfuric acid of 10 N in a spot plate; appearance of a pink-violet colour confirmed the presence of aldehydic group. The other part used for making the 2,4-DNP derivative, which was then recrystalized using benzene as solvent. The colour of the recrystalized 2,4-DNP derivative of aldehyde containing oxidized product was golden-yellow. Melting point measurement of this crude 2,4-DNP derivative (m. p. = 165-166 ºC) has been found to be well match with literature melting point value [1].

The 1H-NMR spectra (Fig. 1) of the oxidized product consists of two singlet sharp peaks corresponding to the –CHO proton and solvent CDCl3. The singlet peak observed at δ 9.742 ppm confirms the presence of aldehyde proton whereas peak at δ 7.282 ppm is due to the CDCl3 solvent.

Fig. 1 The 1H-NMR spectra of the product.

The analysis of our experimental results compared to the literature works are presented in following table.

Table S1. A comparative result for oxidation of methanol using different oxidant and catalyst
Entry / Catalyst / Conditions / kobs / Ref.
1 / [phen] = 0.01 mol dm-3 / [CH3OH] = 0.015 mol dm-3, [BTEACC] = 0.001 mol dm-3, [HClO4] = 2.10 mol dm-3, Temp = 30 ºC. / 7.90×10-4 s-1 / 2
2 / [Ir(III)] = 4.0 × 10-7 mol dm-3 / [CH3OH] = 0.05 mol dm-3, [Ce(IV)] = 2.0 ×10-3 mol dm-3, m = 1.0 mol dm-3, [H+] = 1.0 mol dm-3, Temp = 30ºC. / 1.46×10-4 s-1 / 3
3 / [Rh(III)] = 3.84 × 10-4 mol dm-3 / [CH3OH] = 0.05 mol dm-3, [Periodate] = 2.00 × 10-3 mol dm-3, [KOH] = 2.00 × 10-2 mol dm-3, Temp = 30 ºC / 1.95×10-7 mol-1
dm3 s-1 / 4
4 / [Cu(II)] = 10-5 mol dm-3 / [CH3OH] = 1.5 mol dm-3, [peroxydisulfate] = 8 × 10-3 mol dm-3, Temp = 70 ºC / 2.58×10-2 mol-1/2 dm3/2 s-1 / 5
5 / - / [CH3OH], = 0.1 mol dm-3, [HClO4] = 1.0 mol dm-3, [HCrO4-] = 4.111 × 10-3 mol dm-3, Temp = 35 ºC / 2.476×10-4 s-1 / 6
6 / - / [CH3OH] = 0.6 mol dm-3, pH = 3.42, [Ir(IV)] = 1.18 × 10-4 mol dm-3, Temp = 35 ºC / 0.89×10-4 s-1 / 7
7 / Micellar solution of SDS / [CH3OH] = 1.0 × 10-2 mol dm-3, [vanadium(V)] = 1×10-3 mol dm-3, [H2SO4] = 3.0 mol dm-3, Temp = 40 ºC / 1.166×10-4 s-1 / present work

BTEACC = Benzyl Triethyl Ammonium Chloro Chromate; phen = 1,10-phenanthroline; SDS = sodium dodecylsulphate.

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