Acid–base properties of Cu_1−xCo_xFe₂O₄ferrospinels: FTIR investigations

Glycothermal Synthesis and Catalytic Properties of Nanosized Zn1−x Co x Al2O4 (x = 0, 0.5, 1.0) Spinels in Phenol Methylation

“…This model of phenol adsorption was proposed by Tanabe et al [51] and widely accepted. It was found by Mathew et al that methylated phenols had weak interaction with the surface of spinel-type materials in comparison with phenol and were highly susceptible to desorbing from the surface and just could facilitate efficient methylation on such systems [28]. We observed that acidity and catalytic activity were the highest when ZCAO as catalyst had been used.…”

“…A solution of phenol in methanol with an addition of water (molar ratio 1:5:1, respectively) was introduced to the reactor from the top at pre-determined flow rate equal 1.5 cm 3 /h (load 0.5 h -1 ) by a micro-feed syringe pump. Water was added to the aromatic-alcohol mixture of reactants to prolong the activity of the catalysts during the reaction of methylation [28,[42][43][44]. It is suggested that the addition of water into the substrates mixture lowers coke deposition on the catalyst surface and the share of side reactions is decreased as well [43].…”

“…Among active catalysts in the phenol methylation, materials with spinel structure are very interesting, e.g. ferrites [27][28][29][30] and also others [31][32][33]. Issues concerning the mechanism of phenol alkylation have been presented in many publications.…”

“…Issues concerning the mechanism of phenol alkylation have been presented in many publications. Among them the works of Mathew et al [28,[34][35][36][37] are worth to be quoted, in which the authors have presented a proposal for the mechanism of phenol methylation occurring on well-characterised spinel catalysts. They underlined the role of an acid-base pair sites as the active centres for the ortho-methylation reactions.…”

On the Role of Morphology of CoFeO4 Spinel in Methanol Anaerobic Oxidation

“…Binary and ternary spinel ferrites can be employed as catalysts for reactions, such as oxidative dehydration of hydrocarbons, decomposition of alcohols and hydrogen peroxide, treatment of automobileexhausted gases, oxidation of various compounds, and phenol hydroxidation [28][29][30][31][32][33][34][35][36][37][38][39]. Moreover, these materials exhibit basic properties that make them active in phenolics methylation [36,[40][41][42][43][44].…”