A Green Route to Produce Adipic Acid on TiO₂–Fe₂O₃ Nanocomposites

Abstract

In this work, we study cyclohexene oxidation by molecular oxygen on doped-TiO 2 . The improvement of the oxidizing capacity of titanium oxide by doping with iron oxide at different molar ratios is checked. All materials with different molar ratios (Ti/Fe = 9, 4, and 2) are prepared by the sol-gel method and fully characterized by ICP, XRD, SEM, DR/UV-vis, IR, and N 2 adsorption/desorption. The results show that iron is successfully incorporated into the titanium matrix but the incorporated amount is limited. In catalytic tests, improved activity is noticed while using TiO 2 in the presence of Fe 2 O 3 , which is due the improved oxidation. Conversion in the range of 21-42% depending on the presence of iron oxide was obtained with excellent yield of adipic acid (97% selectivity).

Activity of Bimetallic Gold-Iron Catalysts in Adipic Acid Production by Direct Oxidation of Cyclohexene with Molecular Oxygen

“…Cyclohexene oxidation is one of the most used reactions in the manufacture of fine chemical products [1,2], largely used in different applications and fields [3,4]. Scheme 1 demonstrates the different products that can be obtained from cyclohexene oxidation [1][2][3][4]. The literature evoked the formation of more than seventy products and intermediates (gas, liquid and solid phases) from this reaction depending on the reaction conditions i.e.…”

“…Adipic acid is one of the most important commercially available aliphatic diacarboxylic acids with a large industrial application in Nylon-6 and Nylon-66 manufacture, and intermediates for pharmaceuticals and insecticides [3,4].…”

“…More active forms of oxygen donor were used, such as tbutyl hydroperoxide (TBHP) [5,6] and H2O2 [6] although their disadvantages are to be expansive and harmful to the environment. The use of molecular oxygen in this kind of reaction as oxidant resulted in three important advantages, namely the facility to separate the catalyst after the reaction, a lower energy cost and a higher stability of the irreversible reaction over oxidation products, and the ability to represent the green options [3,4].…”

Epoxidation of cyclohexene with tert‐butyl hydroperoxide catalyzed by mixed oxide V2O5–TiO2

“…Catalytic liquid‐phase epoxidation of cyclohexene is a commercially important reaction that is used to produce cyclohexene oxide, which is an essential organic intermediate in the production of fine chemicals. Moreover, the production of epoxides paves the way to the development of mild and green chemical processes for the synthesis of adipic acid, which is the raw material used in the production of nylon 6,6 . The use of solid catalysts for cyclohexene epoxidation, using TBHP as oxidant, has been reported, with the formation of 2‐cyclohexene‐1‐one, 2‐cyclohexene‐1‐ol, and trans ‐cyclohexane‐1,2‐diol, besides cyclohexene oxide …”

Experimental Design for Modeling and Multi‐response Optimization of Catalytic Cyclohexene Epoxidation over Polyoxometalates

“…A number of studies have reported that cyclohexene epoxidation is affected by multiple parameters, such as the type of oxidant, molar ratio of cyclohexene to the oxidant with various cyclohexene/oxidant molar ratios, temperature, heating mode, catalyst weight, support, and the percentage of active phase to be deposited on the support ( x %/support) . Each group of researchers proposed some specific operating conditions for the reaction.…”