Esterification of Lauric Acid with Glycerol in the Presence of STA/MCM-41 Catalysts

Abstract

Esterification reaction between glycerol and lauric acid in the presence of STA/MCM-41 and H2SO4 catalysts indicated that the activity of synthesized catalyst had been comparable to H2SO4. On the other hand, only di glyceride formation instead of favored mono glyceride has been observed with H2SO4 which had rendered the use of heterogeneous STA/MCM-41 catalyst preferable. Temperature had a decreasing effect on lauric acid conversion due to competitive adsorption of water on catalyst structure. The high mono glyceride selectivity obtained in favor of the desired product was due to shape selectivity of the catalyst. High glycerol amount in feed ratio resulted in deformation of long range order of the catalyst structure and hence a decrease in mono glyceride selectivity. Experiments conducted in identical conditions in the presence of recovered catalysts showed a decrease in lauric acid conversion which had been due to loss of STA from catalyst structure.

Characterizations and Catalytic Activities Investigation of Synthesized Solid-Based Heterogeneous Catalysts in the Esterification Reaction

“…In addition, the irregulations surface areas and pore volumes of the synthesized catalysts were due to the initial value of the P/Po (Table1). The characteristic lattice parameter was calculated from Equation (3) The lattice parameters and the textural properties of samples were measured by BET(N2 adsorption/desorption) and with X-ray diffraction analysis [31,33,34] in the (Table1). …”

“…The pore wall thickness "δ" was then estimated from the average pore diameter (BJH adsorption average pore diameter; dp) and the lattice parameter"a" using Equation (3) [31,33,34].…”

“…Physical Properties of MCM-41 support(surfactant) material and STA/MCM-41catalysts were illustrated in (Table1) before and after reaction. MCM-41 exhibited a type IV isotherm with an H1 hysteresis loop characteristic of mesoporous structure [31,33,34] (Figure 5) and 6. Results obtained with the catalysts indicated a decrease in pore volumes with STA addition without 5%.…”

“…These values were determined by identification of peaks at 1456 -1606, 1450-1604 and 1448-1603 cm -1 for the STA/MCM-41 (W/Si: %1.25-5), respectively. The peaks observed at 1488-1490 cm -1 were attributed to physically adsorbed pyridine(P) [31,33,34]. The characteristic lattice parameter was calculated from Equation (3) The lattice parameters and the textural properties of samples were measured by BET(N2 adsorption/desorption) and with X-ray diffraction analysis [31,33,34] in the (Table1).…”

Solventless esterification of glycerol with p-methoxycinnamic acid catalyzed by a novel sulfonic acid mesoporous solid: Reaction kinetics

“…Among those benefits are the better ease of separation of heterogeneous catalysts and the regeneration of the acid catalyst employed. Furthermore, for this type of reactions, heterogeneous catalysts sometimes have proven to obtain higher yields and greater selectivity to the desired products [1,2]; in addition, they prevent browning of the products caused by other catalysts, such as sulfuric acid, with the subsequent beneficial effect of producing less toxic waste streams. However, it is known that the activity of solid catalysts is still lower than homogeneous for reasons like hindered accessibility of the reactant species to their active centres and their hygroscopic nature, which leads to the absorbed water affecting [3].…”