One-Pot Room-Temperature Synthesis of Mg Containing MCM-41 Mesoporous Silica for Aldol Reactions

Abstract

One-pot synthesis of Mg containing MCM-41 (Mg-MCM-41) materials was carried out by a room temperature (RT) method and by a hydrothermal (HT) method and they were used for aldol condensation of 4-nitrobenzaldehyde and acetone and self-condensation of acetone. The RT method can prepare MCM-41 materials containing large amounts of Mg while maintaining the structural characteristics of MCM-41 even at very low Si/Mg ratios (large Mg loadings), but the HT method cannot. The RT method can also give more active catalysts than the HT method, because the catalysts prepared by the former method are more basic than those prepared by the latter one. The characterization results indicate that Mg atoms in Mg-MCM-41 prepared by the RT method exist as MgO dispersing well on the wall surface of pores, while those in Mg-MCM-41 prepared by the HT method are included in the bulk with a smectite-like structure.

Ethynylation of Formaldehyde over CuO/SiO2 Catalysts Modified by Mg Species: Effects of the Existential States of Mg Species

“…In contrast, SiO 2 -MgO sample possessed the double pore size distribution peak at about 11.0 and 56.2 nm, respectively, suggesting the collapse of mesopore structure of SiO 2 aerogel and the formation of the bimodal porosity. As reported by Shin-Ichiro Fujita et al [38], the different combination way between Si species and Mg species of silica-magnesia composites could affect the growth of mesopore channels.…”

"Brief Analysis of Selected Sorption and Physicochemical Properties of Three Different Silica-Based Adsorbents"

“…An ultrasonic bath (from ULTRON) was used to degas the solvents for 5 minutes immediately after mixing. As adsorbents were used: MCM-41 (mesoporous silica), which was newly synthesized in the Department of Industrial and Materials Chemistry at Rzeszow University of Technology using the modified procedure described previously by Fujita [8], LiChrospher 4000 Si (10 µm) and Silica gel 60 (0.015-0.04 mm)both from Merck. The experiments were carried out using MeOH-water and ACN-water solvent systems containing 95% volume fractions (v/v) of the appropriate organic component.…”

Preparation of Mg, Ca, or Sr-included mesoporous silica from glass bottle waste for recovery of rare earth metal elements

“…Many researchers have reported that other elements can be added to the silica network for application as a heterogeneous catalyst by emphasis on solid acidity. 6–9 Some researchers have also reported a similar catalyst with a solid base 10,11 or with a bimetallic silicate. 12,13 We have also reported that alkali-earth metals have been incorporated into the MPS network to invest in ion-exchangeability.…”