96739-06-9Relevant articles and documents
Biobased catalyst in biorefinery processes: Sulphonated hydrothermal carbon for glycerol esterification
De La Calle, Carlos,Fraile, José M.,García-Bordejé, Enrique,Pires, Elísabet,Roldán, Laura
, p. 2897 - 2903 (2015/05/13)
Sulphonated hydrothermal carbon (SHTC), obtained from d-glucose by mild hydrothermal carbonisation and subsequent sulphonation with sulphuric acid, is able to catalyse the esterification of glycerol with different carboxylic acids, namely, acetic, butyric and caprylic acids. Product selectivity can be tuned by simply controlling the reaction conditions. On the one hand, SHTC provides one of the best selectivity towards monoacetins described up to now without the need for an excess of glycerol. On the other hand, excellent selectivity towards triacylglycerides (TAG) can be obtained, beyond those described with other solid catalysts, including well-known sulphonic resins. Recovery of the catalyst showed partial deactivation of the solid. The formation of sulphonate esters on the surface, confirmed by solid state NMR, was the cause of this behaviour. Acid treatment of the used catalyst, with subsequent hydrolysis of the surface sulphonate esters, allows SHTC to recover its activity. The higher selectivity towards mono- and triesters and its renewable origin makes SHTC an attractive catalyst in biorefinery processes.
Influence of water on the activity and stability of activated Mg{single bond}Al hydrotalcites for the transesterification of tributyrin with methanol
Xi, Yuanzhou,Davis, Robert J.
, p. 190 - 197 (2008/09/19)
Magnesium-aluminum hydrotalcite with a Mg/Al molar ratio of 4 was synthesized by a coprecipitation method. Thermally-decomposed and rehydrated Mg-Al hydrotalcites were used to catalyze the transesterification of tributyrin, a model triglyceride, with methanol (tributyrin:methanol molar ratio 1:30) at 333 K to produce methyl butyrate, monobutyrin, dibutyrin, and glycerol. The pseudo first order rate constants of a three step reaction sequence for tributyrin transesterification were determined by fitting a kinetic model to the experimental data. Although decomposed and rehydrated Mg-Al hydrotalcite was one order of magnitude more active than decomposed Mg-Al hydrotalcite based on surface area measured by N2 adsorption, the activity correlated well to the CO2 adsorption capacity. The most active rehydrated samples also deactivated faster, presumably because butyric acid produced by hydrolysis of ester with adsorbed water reacted with the base sites. The areal rate and CO2 adsorption capacity of decomposed-rehydrated Mg-Al hydrotalcite decreased as the interlayer water was removed by heating.
Acyl transfer isomerization of glycerol 1,2-dibutyrate and propane-1,2-diol 1-butyrate
O'Connor, Charmian J.,Barton, Richard H.
, p. 455 - 459 (2007/10/03)
The speciation of mixed butyrylglycerols (glycerol butyrates) and propanediol butyrate esters in the product mix from lamb pregastric lipase-catalysed hydrolysis of tributyrylglycerol and propane-1,2-diol dibutyrate has been examined by 13C n.m.r. spectroscopy. Samples from the quenched reaction mixture were extracted and allowed to stand in emulsion systems made up in bis tris propane buffer or water, pH 7.0, and in the absence of enzyme. There is clear evidence of uncatalysed conversion of rac-l,2-dibutyrylglycerol into the 1,3-isomer to form an equilibrium mixture containing c. 60-67% 1,3-isomer, and of conversion of propane-l,2-diol 1-butyrate into propane-l,2-diol 2-butyrate to form an equilibrium mixture containing c. 67% 2-monoester. Conversion kinetics to reach equilibrium are first order. Rate constants for acyl transfer of the diacylglycerol are 0.48 h-1 (in water) and 0.68 h-1 (in buffer) at 50°C, while those for acyl transfer of the 1-monoester are 0.72 h-1 (50°C) and 0.35 h-1 (35°C).
