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The production of solketal and conversion of glycerol takes a major importance in the field of the sustainability of the biodiesel industry. The synthesis of (2,2-dimethyl-1,3-dioxolan-4-yl)methanol by the acetalization of glycerol with acetone successfully applied out using various Algerian acid activated clays (maghnia-H+) under autogenous pressure and without solvent. The acid catalyst clays are prepared by an easy technique by activation with the available and low-cost Maghnia clay. The purified Maghnia clay named ALC and the resulting series of acid-activated clays AL1, AL2, AL3, and AL4 are characterized by X-ray Fluorescence (XRF) investigation, N2-adorption/desorption Brunauer–Emmett–Teller  (BET) surface area, X-rays Diffraction (XRD), Fourier Transform Infra Red (FT-IR) spectroscopy, SEM microscopy and the cation exchange capacity (CEC) with copper bisethylenediamine complex method, in order to study the effect of activation at the acid and the catalytic behaviour in the acetalization reaction. The results show a high catalytic activity whose that the yield of solketal production interest reached 95 % at a temperature of 40 °C for a reaction time of 48 hours with full selectivity and glycerol conversion reaching up to 89 %. A mechanistic is proposed to explain the chemoselective of solketal production. These results indicate the potential of this Algerian acid activated clays catalysts for the acetalization of glycerol for an environmentally benign process. Copyright © 2018 BCREC Group. All rights reservedReceived: 28th March 2018; Revised: 17th October 2018; Accepted: 30th October 2018; Available online: 25th January 2019; Published regularly: April 2019How to Cite: Alali, K., Lebsir, F., Amri, S., Rahmouni, A., Srasra, E., Besbes, N. (2019). Algerian Acid Activated Clays as Efficient Catalysts for a Green Synthesis of Solketal by Chemoselective Acetalization of Glycerol with Acetone. Bulletin of Chemical Reaction Engineering & Catalysis, 14 (1): 130-141 (doi:10.9767/bcrec.14.1.2445.130-141)Permalink/DOI: https://doi.org/10.9767/bcrec.14.1.2445.130-141

To date, the Wittig reaction remains the most commonly used method in organic chemistry. The synthesis approach yields to a possible functionalization of the olefin product through the transformation of the carbonyl function (ketones or aldehydes) with a phosphoniumylide. In the present work, the two approaches are used to describe the mechanism of the Wittig reaction. Static quantum calculations at the DFT level of theory with a B3LYP functional and 6-31 g(d, p) basis set are carried out and correlated to metadynamics calculations, exploring the free energy landscape of the reaction. The free energy barriers are calculated along the trajectory path, and the mechanism is discussed with the main features observed in the MTD calculations when compared to static quantum investigations. The latter do not allow for the identification of all points that may occur along the reaction path. Static quantum calculation converges to limited geometry states, while the metadynamics converges to several metastable and stable geometries and configurations. Moreover, the strong dependence of the reaction dynamics upon the functional and pseudopotential used highlights the importance of the dispersion forces along the reaction path. A complete description of the reaction mechanism from both the free energy standpoint and the structural configurations of the molecular species is discussed in detail. The differences in the free energy profile are discussed in terms of the limited account of the dispersion interactions within the DFT approach and the standard local XC functionals, confirming the strong non-covalent interactions and molecular rearrangement of charged species that take place all along the reaction path.

A series of poly (methacrylic acid-Co-maleic acid), P(MAA-MA), hydrogels have been prepared by free radical polymerization in aqueous medium using different amount of maleic acid (MA) (0-5 wt.%), initiated by potassium persulfate (KPS) in the presence of N,N'-methylenebisacrylamide (MBA) as a crosslinking agent. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscope (SEM) techniques were used to characterize the prepared hydrogels. Their swelling behaviours were investigated according to the maleic acid content and pH of solution. Kinetic swelling of hydrogels was studied too. The results showed that the swelling ratios increase with increasing the maleic acid content. Kinetic studies showed good fitting to pseudo-second order equation. The prepared hydrogels obeyed non-Fickian water diffusion.