621-61-4Relevant academic research and scientific papers
Synthesis of glycerol monostearate over K2CO3/γ-Al2O3 catalyst
Zhou, Lu,Gu, Yi,Hong, Mei,Xiao, Guomin
, p. 458 - 462 (2015/01/30)
The synthesis of glycerol monostearate by transesterification of methyl stearate with glycerol can be carried out in the presence of basic catalyst. The absence of solvent in the reaction system would result in a low conversion of methyl stearate as a consequence of low miscibility between reactants. The addition N,N′-dimethyl formamide as solvent improved the activity of the catalyst and selectivity to glycerol monostearate. Different K2CO3-containing γ-Al2O3 catalysts were made and used in the reaction. The results showed that catalyst with higher basicity could lead to better reactant's conversion but poorer selectivity to glycerol monostearate and the optimal load of K2CO3 inducing the highest yield to glycerol monostearate was 20 % mass fraction of γ-Al2O3 supporter. At a glycerol/methyl stearate ratio of 6:1, 165°C, 2 wt. % catalyst amount, a yield of 82.21 % of glycerol monostearate was achieved after 5h.
Homogeneous Tubular-Flow Process for Monoolein Preparation
Herskowitz, Moti,Landau, Miron V.,Koukouliev, Slava,Zarchin, Ruby,Nehemya, Roxana Vidruk,Wee, Lik H.,Martens, Johan A.
, p. 1525 - 1529 (2015/10/12)
Esterification of fatty acids with glycerol is characterized by negligible solubility of the two liquid phases. The reactions to mono-, di- and triglycerides taking place in the fatty acid phase, are limited by chemical equilibrium. The scope of this study is to investigate in a tubular reactor the conversion of a homogeneous mixture of oleic acid and glycerol in tert-butanol. The liquid composition in this study was 1 mol of oleic acid, 6 mol of glycerol and 14 mol of tert-butanol. Experiments were conducted in a tubular reactor at 35 atm over a temperature range of 200-240 °C and residence times of 0.7-17.6 h to determine the kinetics and the chemical equilibrium. The selectivity to monoolein was >95 mol %. A reversible second order reaction fits the data well.
Optically active monoacylglycerols: Synthesis and assessment of purity
Chen, Chao-Yuan,Han, Wei-Bo,Chen, Hui-Jun,Wu, Yikang,Gao, Po
, p. 4311 - 4318 (2013/07/26)
Despite their simple structures, synthesis of 1(or 3)-acyl-sn-glycerols remains a challenge that cannot be ignored because of facile acyl migrations, which not only complicate the synthesis but also make direct GC or HPLC analysis unfeasible. Assessment of the optical purity of monoacylglycerols has, to date, relied almost exclusively on specific rotation data, which are small in value and thus insensitive to impurities. Now, a simple means to "magnify" the small specific rotations has been found, along with practical methods for the measurement of both 1,2-and 1,3-acyl migrations, which offer a convenient and straightforward alternative to Mori's NMR analysis of Mosher esters. With the aid of these methods, a range of conditions for deacetonide removal were examined en route to the synthesis of two natural monoacylglycerols. Refined hydrolysis conditions, along with useful knowledge about the solubility and reactivity of substrates with an ultra long alkyl chain are also presented. Copyright
13C NMR quantification of mono and diacylglycerols obtained through the solvent-free lipase-catalyzed esterification of saturated fatty acids
Fernandes, Jane Luiza Nogueira,De Souza, Rodrigo Octavio Mendonca Alves,De Vasconcellos Azeredo, Rodrigo Bagueira
experimental part, p. 424 - 428 (2012/08/14)
In the present investigation, we studied the enzymatic synthesis of monoacylglycerols (MAG) and diacylglycerols (DAG) via the esterification of saturated fatty acids (stearic, palmitic and an industrial residue containing 87% palmitic acid) and glycerol in a solvent-free system. Three immobilized lipases (Lipozyme RM IM, Lipozyme TL IM and Novozym 435) and different reaction conditions were evaluated. Under the optimal reaction conditions, esterifications catalyzed by Lipozyme RM IM resulted in a mixture of MAG and DAG at high conversion rates for all of the substrates. In addition, except for the reaction of industrial residue at atmospheric pressure, all of these products met the World Health Organization and European Union directives for acylglycerol mixtures for use in food applications. The products were quantified by 13C NMR, with the aid of an external reference signal which was generated from a sealed coaxial tube filled with acetonitrile-d3. After calibrating the area of this signal using the classical external reference method, the same coaxial tube was used repeatedly to quantify the reaction products. Copyright
Design of well balanced hydrophilic-lipophilic catalytic surfaces for the direct and selective monoesterification of various polyols
Kharchafi, Ghizlane,Jerome, Francois,Adam, Isabelle,Pouilloux, Yannick,Barrault, Joel
, p. 928 - 934 (2007/10/03)
The transesterification process is a well known reaction of organic chemistry. However, the monoesterification of unprotected polyols such as glycerol or sucrose is much more complex and the design of selective catalysts is becoming a huge challenge in order to avoid many protection and deprotection steps, harmful for the cost and the environmental impact of the resulting process. In this study, we showed that the control of the hydrophilic-lipophilic balance of heterogeneous catalysts is a crucial key in order to tune both the catalyst activity and the monoester selectivity. Indeed, whereas homogeneous guanidine led to low selectivity toward monoesters, its anchorage on a hydrophilic solid support such as silica allowed us to prepare two basic hybrid organic-inorganic materials able to selectively afford monoesters in high yield and in an environmentally-friendly process, at low temperature and starting from an equimolecular mixture of unprotected polyols and various fatty methyl esters. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2005.
Synthesis and analysis of symmetrical and nonsymmetrical disaturated/monounsaturated triacylglycerols
Adlof, Richard O.,List, Gary R.
, p. 2096 - 2099 (2007/10/03)
Symmetrical disaturated triacylglycerols of the structure SUS, where S is stearic acid (18:0) and U is an unsaturated fatty acid, either oleic (O; 9cis-18:1), linoleic (L; 9cis, 12cis-18:2), or linolenic (Ln; 9cis, 12cis, 15cis-18:3), are important components providing functionality to interesterified fat blends and structurally modified oils. Nonsymmetrical triacylglycerols of the structure SSU can significantly change melting point and solid fat content profiles. To characterize the physical properties of pure and symmetrical and nonsymmetrical triacylglycerol mixtures, the same reaction sequence has been used to prepare multigram quantities of triacylglycerols SUS and SSU. Tristearin was converted to a mixture of mono-, di-, and triacylglycerols, and the 1,3- and 1,2-diacylglycerol fraction was isolated by silica column chromatography. The 1,3-diacylglycerols were removed by crystallization from acetone and esterified with the appropriate fatty acid to form the symmetrical triacylglycerols with >99% SUS structure. The more difficult to obtain 1,2-diacylglycerols were prepared by esterification of the enriched 1,2-diacylglycerol fraction (80-86% 1,2-diacylglycerols) remaining after removal of much of the 1,3-isomer by crystallization, but silver resin or silver nitrate impregnated silica gel chromatography was required to isolate the nonsymmetrical triacylglycerols. SSL and SSLn were prepared in purities of >98% by this procedure, but not SSO. Silver ion HPLC was found to be as accurate as, and more rapid than, lipolysis/gas chromatography for the determination of the isomeric purities of the synthesized triacylglycerols.
Preparation of monoglycerides by guanidine-catalyzed processes
Guimaraes Aguiar, Leila M.,Vargas, Rogerio Matheus
, p. 755 - 756 (2007/10/03)
Glycerolysis of methyl stearate and tristearin has been carried out in the presence of alkylguanidines - strong nonionic bases - as catalysts. When applied at 10 mol%, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1,2,3-tricyclohexylguanidine, and 1,3-dicyclohexyl-2-n-octylguanidine give monoglycerides in more than 90% selectivity, in a maximum of 6 h reaction time.
Preparation of 2-O-arachidonoyl-1-O-stearoyl-sn-glycerol and other di-O-acyl glycerol derivatives
Gaffney, Piers R.J.,Reese, Colin B.
, p. 2539 - 2542 (2007/10/03)
R(-)-2,3- and S(+)-1,2-O-Isopropylidene-sn-glycerols (4 and 9) are converted into 2-O-arachidonoyl-1-O-stearoyl and 2-O-arachidonoyl-3-O-stearoyl-sn-glycerols (2 and 3, respectively); glycerol is also converted into its racemic 1,2- and its symmetrical 13-di-O-linoleoyl derivatives (14 and 17, respectively).
