Simple and Green Adipic Acid Synthesis from Cyclohexanone and/or Cyclohexanol Oxidation with Efficient (NH4)xHyMzPMo12O40 (M: Fe, Co, Ni) Catalysts

Abstract

The oxidation of cyclohexanone and/or cyclohexanol to adipic acid (AA) was performed at 90 °C with a reaction time of 20 h, in the presence of H2O2 as oxidant and transition metal substituted ammonia polyoxometalates of formula, (NH4)xHyMzPMo12O40 (M: Fe, Co, or Ni, and x = 2.5 or 2.28) as catalysts. The catalytic results showed that the AA yield is sensitive to the transition metal nature and to the reaction conditions (sample weight and substrate amount). The (NH4)2.29H0.39Co0.16PMo12O40 was found to be the better catalytic system toward AA synthesis from cyclohexanone oxidation, with 40% of AA yield

Cyclohexanone Oxidation over H3PMo12O40 Heteropolyacid via Two Activation Modes Microwave Irradiation and Conventional Method

“…Preliminary catalytic tests carried out with powers of 100, 180, and 300 watt and reaction times varying between 5 and 60 min, have showed that 100 watt and 30 min are the best parameters to obtain optimal AA yield. While, previous works performed under conventional heating mode have showed that 20 h is the required reaction time to obtain optimal AA yield [14][15][16][22][23][24]. These results evidenced that the use of microwaves irradiation permits to reduce reaction time from 20 h to 30 min and to reduce energy.…”

“…This has as for consequence the formation of peroxocomplexes highlighted by several techniques (X-ray diffraction, FTIR, and Raman spectroscopies). These complexes, with an oxidizing power stronger than that of H2O2, have been shown to be very active in several reactions [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]29]. In our case, we could admit that the reduced POM, from the first stage, oxidizes and simultaneously forms peroxocomplexes "peroxo-POMox".…”

“…The reaction of cyclohexanone oxidation to adipic acid, using conventional method (reflux heating) in the presence of Keggin-type phosphomolydates, has already been the subject of several studies [14][15][16][22][23][24]. In this work, microwaves irradiation (MI), as new activation mode, was introduced to test the feasibility of this reaction using H3PMo12O40 (noted PMo12) as catalyst.…”

Transition metal-substituted Keggin-type polyoxometalates as catalysts for adipic acid production

“…With an equimolar mixture (50/50%), AA formation was not observed, contrarily to the industrial process. The negative effect of alcohol presence in the reaction mixture has already been mentioned [4,8,20,26,28,39]. It was attributed to the formation of hydrogen bonds between the C=O group of the ketone and the hydrogen of the C-OH group of cyclohexanol, which makes the -one oxidation of the mixture difficult.…”

Polyvinylpyrrolidone-Ferrocyanide Catalysts for Cyclohexane Oxidation

“…Liquid phase cyclohexane oxidation is an industrially significant process [1,2]. Partial cyclohexane oxidation products -cyclohexanol and cyclohexanone -are used to produce caprolactam, adipic acid, polyamide fibers, nylon-6 and nylon-66 [3,4].…”