Microwave rehydrated Mg–Al-LDH as base catalyst for the acetalization of glycerol

Abstract

Acetalization of glycerol with aldehydes to form cyclic acetals is an industrially important reaction and is generally carried out using acid catalysts.

Effect of Bio‐Based Aldehyde Structure on the Conversion and Selectivity Towards Glycerol Acetal Over Amberlyst‐46 by Using a Solvent‐Free Approach

“…Similar pattern with drastic decrease in conversion and improved selectivity by p ‐anisaldehyde has also been reported by others [43] . This reduced reactivity is due to the introduction of an electron donating group on para position on the aromatic ring [44] of the aldehyde rendering the electrophilic site [45] . This hypothesis is supported by higher conversion reported in glycerol acetalization with aromatic aldehyde substituted with electron withdrawal group [40,46,47] .…”

“…[43] This reduced reactivity is due to the introduction of an electron donating group on para position on the aromatic ring [44] of the aldehyde rendering the electrophilic site. [45] This hypothesis is supported by higher conversion reported in glycerol acetalization with aromatic aldehyde substituted with electron withdrawal group. [40,46,47] Thus, we showed here different types of substituents in aldehydes could affect the selectivity towards 1,3-dioxan-5-ol.…”

Catalytic Acetalization: An Efficient Strategy for High-Value Utilization of Biodiesel-Derived Glycerol

“…The conversion of glycerol is negligible in the absence of a catalyst (Table 1, Entry 1), while it is significantly enhanced with ester sulfate-functionalized IL catalyst; for example, 73-86% of glycerol conversion and almost 97% acetal selectivity were demonstrated when ester sulfate-functionalized IL was used ( 4 ], 86% of glycerol was converted with 84% acetal yield, 28% of which consists of a six-membered compound, a versatile fine chemical, and an important intermediate in organic industrial chemistry. This six-membered product selectivity is higher than that found in many previous studies [5,14,16]. Generally, IL composes of an organic cation and an inorganic or organic anion, so it usually has a large structure than conventional homogeneous inorganic acidic catalysts (such as H 2 SO 4 and HCl).…”

Room temperature synthesis of glycerol carbonate catalyzed by spray dried sodium aluminate microspheres

“…The intensity of the peak at 1420 cm -1 -attributed to carbonates -increased with the decrease in particle size, which figures a higher amount of adsorption sites for carbonate species on the samples with smaller crystallites The basicity of the catalysts was evaluated using temperature programmed CO 2 desorption (CO 2 -TPD) (Figure 3). The method is known to allow a quantitative analysis of basicity, with a distinction between weak, moderate and strong sites [26,27]. It should be noted, however, that a bulk gas/solid reaction may also occur during CO 2 adsorption, transforming sodium aluminate into sodium carbonate.…”