Synthesis, characterization and catalytic activity studies on cordierite honeycomb coated with ZrO2 based solid super acids

Abstract

Cordierite honeycomb coated with solid acids such as ZrO 2 , Mo/ZrO 2 and W/ZrO 2 were synthesized. These solid acid catalysts were also synthesized in their powder forms. The catalytic materials were characterized for their physicochemical properties such as surface area, surface acidity, crystallinity and morphology by using techniques such as BET, NH 3 -TPD/n-butylamine back titration, powder XRD and SEM respectively. The catalytic activity of these catalytic materials was determined in an acid catalyzed transesterification reaction of methyl salicylate with phenol to synthesize phenyl salicylate (salol). The effect of concentration of Mo or W ions on ZrO 2 , nature of the catalyst (whether honeycomb coated or powder form), reaction temperature, reaction time and reusability of the catalytic material in transesterification was studied. Formation of diphenyl ether as a byproduct was observed on increasing the concentration of Mo or W ions on ZrO 2 and also at higher reaction temperature. The catalytic activity of catalytic materials was correlated with surface acidity and the crystalline phases of catalytic material. Transesterification reactions were also carried out with methyl salicylate and benzyl alcohol or cyclohexanol to synthesize their respective salicylate esters. A probable mechanism of transesterification of methyl salicylate with an alcohol is also proposed. The honeycomb catalysts were found to be efficient, ecofriendly, economical and reusable catalysts compared to their powder forms.ß 2012 Published by Elsevier Masson SAS on behalf of Acade ´mie des sciences.

Cordierite Honeycomb Monoliths Coated with Zirconia and Its Modified Forms for Biodiesel Synthesis from Pongamia glabra

“…The reaction mixture was refluxed at refluxing temperature (~65 °C) for 2 h. After a stipulated reaction period (2 h) the hot reaction mixture was filtered to separate the HC catalyst. The %FFA was measured by determining its acid value by following an acid-base titration method as described elsewhere [24].…”

Catalytic Synthesis of Salicylate Esters over Cordierite Honeycomb Coated with Mo (VI)/ZrO<sub>2</sub>

“…The total surface acidity (TSA) values of ZrO 2 and 6% MZ (both in HC coated and powder forms) are given in Table 1. Zirconia was found to be less acidic when compared to 6% MZ indicating that the incorporation of Mo (VI) ions increases the number of acid sites on zirconia thereby increasing the TSA values of 6% MZ [9].…”

Methoxymethylation of Substituted Alcohols using Dimethoxymethane over Mo(VI)/ZrO2

“…The broad band at 824 cm -1 were shown that the Mo-O-MO stretching mode of vibration for MoO 3 . The band at about 1638 cm -1 attributed acidic hydroxyl proton and about 3421 cm -1 stretching mode of hydrogen bonding exists in all the catalysts [33,34].…”