Ketalization Of Glycerol Research Articles

Green synthesis of cyclohexanone glycerol ketal catalyzed by a solid superacid

Abstract This paper discusses the synthesis of a glycerol ketal compound obtained from condensation reaction of cyclohexanone with glycerol catalyzed by a solid superacid. The solid superacid SO42-/TiO2-La2O3 was prepared using coprecipitation and impregnation method and characterized by X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy and elemental analysis. The surface acidity was measured by thermogravimetric analysis of adsorbed n-butylamine. In order to achieve the optimal reaction conditions, five impact factors: molar ratio of glycerol to cyclohexanone, catalyst calcination temperature, reaction time, catalyst amount and molar ratio of Ti/La were investigated in the experiments. Synthesized ketal compounds were analyzed by GC-MS/MS. Under the best conditions, the cyclohexanone glycerol ketal yield could reach up to 97%.

Ketalization of Glycerol with Acetone to O-Heterocyclic Compounds over ZrO2-SiO2 Solid Acid Catalysts

Ketalization of Glycerol with Acetone to O-Heterocyclic Compounds over ZrO2-SiO2 Solid Acid Catalysts

Glycerol ketals: Synthesis and profits in biodiesel blends

Surplus of glycerol due to the increase of biodiesel production has become an economic drawback for the development of biofuel itself. In this work, we show that it is possible to take advantage of glycerol for the synthesis of derivatives such as ketals, which can be used in biodiesel blends. The synthesis of ketals has been successfully carried out in good yields by using a cheap and reusable catalyst, K10 montmorillonite. The analysis of biodiesel blends quality parameters revealed the improvement of their cold properties, but some parameters such as fatty acid methyl ester (FAME) content and oxidation stability do not reached EN14214 specifications. In order to overcome this issue, esterification of the free hydroxyl group has been carried out leading to products with improved and promising properties for biodiesel blends.

Ketalization of glycerol to solketal in supercritical acetone

In the last few years, the increasing production of biodiesel has led to an overproduction of glycerol, the main byproduct of this industry. This paper reports on the ketalization of glycerol in supercritical acetone to give solketal (4-hydroxymethyl-2,2-dimethyl-1,3-dioxolane), an oxygenated compound useful as chemical and fuel additive for gasoline, diesel and biodiesel. The application of supercritical fluids (SCFs) in the chemical synthesis was explored to carry out reactions to obtain the above cyclic ketal. The experimental results reveal a drastic change in the reaction behavior when the critical condition of acetone is reached ( T = 508 K). Below 508 K the reaction rate of solketal production is very low, but above this temperature a rapid increase in the reaction rate is observed. Finally, the reaction rate is stabilized at 533 K and higher temperatures due to the conversion of glycerol to acrolein and polymeric products as side reactions.

00/01435 Thermal analysis of alternative diesel fuels from vegetable oils

Comparative results on the evaluation of cold-flow improvers for palm biodiesel, of the type glycerol ketals, glycerol acetates and branched alcohol-derived fatty esters, are presented. Glycerol ketals were obtained through the reaction of glycerol with acetone catalyzed by p-toluene sulfonic acid. Glycerol acetates were obtained through the reaction of glycerol with acetic acid catalyzed by p-toluene sulfonic acid. Branched alcohol-derived fatty esters were obtained through the esterification of palm-derived fatty acids with branched alcohols, catalyzed by sulfuric acid. These additives were mixed with palm biodiesel at levels of 1%, 3%, 5% and 10% and the effects on pour and cloud points were measured. Crystallization points of pure and additivated palm biodiesel were determined by differential scanning calorimetry (DSC). Effects of additives on the crystallization process were analyzed by measuring the size of crystals formed upon cooling. The best cold-flow improvers were 2-butyl esters of palm oil; upon addition of 5% of this additive the pour and cloud points were reduced about 6 °C. DSC analyses accurately showed that the additives decrease decrystallization points of biodiesel. Particle size analyses by dynamic light scattering showed that the additives act by decreasing crystal sizes; besides, this technique proved to be an easy and accurate way to determine the cold-flow behavior of biodiesel. Addition of 2-butyl esters of palm oil did not have any detrimental impact on the fuel properties of palm biodiesel.

Application of pig liver esterase catalyzed transesterification in organic media to the kinetic resolution of glycerol derivatives

The PLE/MPEG catalyzed transesterification of the glycerol ketals rac- 1a and rac- 1d– f with vinyl propionate in toluene proceeded with good selectivities (E=24–34) and gave the enantiomerically enriched S-alcohols 1a and 1d– f, and the S-esters 2a and 2d– f. High selectivities (E=99 and E≥200) were observed in the transesterification of the glycerol ether rac- 3 and its desoxy analog rac- 5, both having a secondary hydroxy group, with PLE/MPEG. In transesterifications in organic media PLE exhibited a much higher enantioselectivity than in hydrolysis in water.

Alkoxyalkyl‐substituted glycerol acetals: New hydrophobic intermediates for surfactant synthesis

In acid‐catalyzed, one‐step reactions of monofunctional alcohol (I) and glycerol mixture with a simple α,β‐unsaturated carbonyl compound (acrolein, crotonaldehyde or methylvinyl ketone), four component glycerol acetals [mixtures ofcis‐+trans‐2‐(2‐alkoxyalkyl)‐substituted derivatives of 4‐hydroxymethyl‐1,3‐dioxolanes and 5‐hydroxy‐1,3‐dioxanes] or two component glycerol ketals [mixtures ofcis‐+trans‐2‐(2‐alkoxyethyl)‐2‐methyl‐4‐hydroxymethyl‐1,3‐dioxolanes] were obtained, respectively. These compounds may be used as a new group of hydrophobic intermediates for synthesis of chemodegradable surfactants, which rapidly hydrolyze to nonsurfactant compounds in acidic aqueous solutions. Methods of synthesis, yields, compositions and chemical structures of components of reaction products, and products of their chemical degradation have been discussed.

Glyceride isomerizations in lipid chemistry

AbstractIsomerization of isopropylidene glycerol ketals and benzylidene glycerol acetals was studied, and isoraerization equilibria were established. Reaction of benzaldehyde with glycerol gave four benzylidene glycerol isomers, which were separated by column chromatography and characterized by NMR spectroscopy and other methods.Isomerization of 1‐ and 2‐monoglycerides and of 1,2‐ and 1,3‐diglycerides, and their separation by column chromatography, are described. Mechanisms of isomerization in mono‐ and diglycerides and factors which affect them are discussed.Isomerization of 1‐ and 2‐glycerophosphates and of cyclic glycerophosphates by acid and base was also studied. Hydrolysis products of L‐3‐glycerylphosphorylcholine and 2‐glycerylphosphorylcholine were separated by column chromatography and characterized by periodic acid oxidation, optical rotation, and NMR spectroscopy. No isomerization of unhydrolyzed L‐3‐glycerylphosphorylcholine and 2‐glycerylphosphorylcholine was observed. Evidence indicated that acid‐catalyzed hydrolyses of phosphoglycerides are under thermodynamic control whereas most base‐catalyzed hydrolyses are under kinetic control.