Preparation of p-isopropylbenzaldehyde ( p-cuminal) by direct electrochemical oxidation of p-isopropyltoluene ( p-cymene) in methanolic medium

• Published in: Electrochimica acta Vol. 46; no. 6; pp. 875 - 880
• Main Authors: Vaudano, F, Tissot, P
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2001; Elsevier
• Subjects: Anodic oxidation; Chemistry; Electrochemistry; Electroorganic synthesis; Exact sciences and technology; General and physical chemistry; Kinetics and mechanism of reactions; Noncondensed benzenic compounds; Organic chemistry; p-Isopropylbenzaldehyde; p-Isopropyltoluene; Preparations and properties; Electroorganic synthesis; p-Isopropyltoluene; Anodic oxidation; p-Isopropylbenzaldehyde; Hydrocarbon; Experimental study; Anodization; Acidic solution; Benzaldehyde(4-isopropyl); Gas chromatography; Organic solvent; Cymene; Oxidative degradation; Benzenic compound; Toluene derivatives; Electrochemical reaction; Degradation product; Mass spectrometry; Methanol
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/S0013-4686(00)00673-3

The direct anodic oxidation of
p-isopropyltoluene (
p-cymene) in methanolic solutions gives in part the
p-isopropylbenzaldehyde dimethyl acetal, which produces the
p-isopropylbenzaldehyde (
p-cuminal) by hydrolysis in sulfuric acid medium. Since several parallel reactions are possible, we have investigated, in an undivided cell equipped with a magnetic stirrer, the influence of the following parameters on the
p-cuminal production: nature of the solvent, nature of the supporting electrolyte, nature of the anode, initial
p-cymene concentration, anodic current density, amount of electricity supplied to the system and temperature. For the optimum conditions, the conversion of
p-cymene was higher than 95% and the
p-cuminal selectivity was 58–59%. We have also investigated the production of
p-cuminal in two electrochemical cells transposable on a large scale. The former was a reactor equipped with a cylindrical graphite anode and the latter was an electrochemical cell equipped with a flow-through reticulated vitreous carbon anode. In these cases, we observed that the
p-cuminal production increases with either the rate of stirring or the flow rate of the electrolyte.