1072-36-2Relevant academic research and scientific papers
Direct conversion of linoleic acid over silver catalysts in the presence of H2: An unusual way towards conjugated linoleic acids
Kreich, Markus,Claus, Peter
, p. 7800 - 7804 (2005)
(Chemical Equation Presented) A silver lining: The isomerization of conjugated double bonds over silver catalysts in the presence of hydrogen are unusual and hitherto unknown. Silver catalysts control the selectivity of the extremely difficult isomerization of linoleic acid towards the physiologically important 9-cis,11-trans- and 10-trans, 12-cis-unsaturated isomers, which are anticarcinogenic and antiarteriosclerotic agents (see scheme, CLA = conjugated linoleic acids).
Heterogeneous catalytic production of conjugated linoleic acid
Bernas, Andreas,Kumar, Narendra,Maeki-Arvela, Paeivi,Holmbom, Bjarne,Salmi, Tapio,Murzin, Dmitry Yu.
, p. 341 - 352 (2004)
Kinetic experiments in selective isomerization of technical grade (～55%) linoleic acid to cis-9,trans-11-conjugated linoleic acid (B) and trans-10,cis-12-conjugated linoleic (E) acid isomers were performed batchwise at 165°C over two series of supported metal catalysts, i.e., hydrogen preactivated and nonpreactivated. Activated carbon- and aluminium oxide-supported Ru, Pd, Os, Ir, and Pt-Rh catalysts with 5 wt % metal loading were screened. Catalyst characterization was done by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy-energy-dispersive X-ray analysis (SEM-EDX), temperature-programmed desorption of hydrogen (H2-TPD), direct current plasma atomic emission spectrometry (DCP-AES), and nitrogen adsorption techniques. Over such catalysts, the reaction scheme involves six steps: (1) double bond migration of linoleic acid to conjugated linoleic acid, (2) positional and geometric isomerization of conjugated linoleic acid, (3) double bond hydrogenation of linoleic acid to monoenoic acids, (4) double bond hydrogenation of conjugated linoleic acid to monoenoic acids, (5) positional and geometric isomerization of monoenoic acids, and (6) double bond hydrogenation of monoenoic acids to stearic acid. Over Ru/C catalyst, chemisorbed hydrogen on the metal surface dramatically increased the linoleic acid isomerization rate in a diluted system as an astoichiometric component-enhancing double bond migration but decreased the isomerization rate by promoting deactivation in a solvent-free system. Over Ru/Al2O3 catalyst, on the other hand, dissociated hydrogen increased the isomerization rate for both the diluted and nondiluted systems. The effect of eliminating the solvent was an increase of the turnover frequency (TOF) at 165°C by a factor of 12 with respect to that shown in a diluted system. At the same conversion carbon-and aluminium oxide-supported Ru catalyst showed higher selectivity toward B and E than carbon-supported Pd, Os, Ir, and Pt-Rh catalysts.
Synergetic effect of ruthenium and basicity sites in the Ru-MgAl catalyst for hydrogen-free production of conjugated linoleic acids
Chen, Jiebo,Chen, Xinxiang,Zheng, Ying,Li, Qinglu
, p. 20248 - 20255 (2015)
A series of Ru-MgAl composite oxide catalysts prepared by calcining the ruthenium grafted hydrotalcite-like precursor at various temperatures were used in the hydrogen-free production of conjugated linoleic acid. The effect of calcination temperature on the textural, base and catalytic properties of the materials was investigated. Results indicated that the Ru-MgAl composite oxides calcined at 450 °C showed high activity, namely, CLA productivity, CLA production rate and TOF up to 1.52 g CLA g (CLA) L-1 (solvent) min-1, 284 g (CLA) g-1 (Ru) h-1 and 102.6 mol (LA converted) mol-1 (Ru) h-1. Moreover, the biologically active CLA isomers, cis-9, trans-11, trans-10, cis-12 and trans-9, trans-11-CLA, were the main products, while almost no hydrogenated products were formed. Meanwhile, the role of ruthenium and basicity sites in the catalytic reaction has been studied. It was found that the basicity sites of the Ru-MgAl catalyst and the ruthenium activity sites seem to have a synergic effect on the catalytic reaction. The possible reaction mechanism for the isomerization was also proposed. This journal is
Investigation of Micellization and Vesiculation of Conjugated Linoleic Acid by Means of Self-Assembling and Self-Crosslinking
Fan, Ye,Fang, Yun,Ma, Lin,Jiang, Hang
, p. 179 - 188 (2015)
Bioactive and biocompatible conjugated linoleic acid (CLA) has been only considered as a food or medicine ingredient due to its rare natural occurrence. In this work, the surface activities and pH-induced self-assembling behaviors of the semi-synthetic CLA molecules into micelles or vesicles were systematically investigated. First, the self-assembling of CLA was studied in detail, and it was found that aside from temperature and ionic strength, pH is the prominent factor affecting the self-assembling of CLA. Moreover, stable CLA ufasomes (unsaturated fatty acid liposomes) in uniform size were obtained by self-crosslinking of the CLA ufasomes, and the morphologies of the crosslinked CLA assemblies were recorded by transmission electron microscopy, which made known the pH-induced formation of the CLA ufasomes or the CLA micelles. The crosslinked CLA assemblies presented improved properties such as a higher calcium stability, a lower lime soap dispersing requirement and a better solubilization ability than that of the CLA molecules themselves or the pre-crosslinked linoleic acids. These investigations could be helpful for comprehensively understanding effects of environment factors on self-assembling behaviors of conjugated fatty acids and responsive polymerization of polymerizable surfactants.
A New Heterogeneously Catalytic Pathway for Isomerization of Linoleic Acid over Ru/C and Ni/H-MCM-41 Catalysts
Bernas, Andreas,Laukkanen, Pekka,Kumar, Narendra,Maeki-Arvela, Paivi,Vayrynen, Juhani,Laine, Ensio,Holmbom, Bjarne,Salmi, Tapio,Murzin, Dmitry Yu.
, p. 354 - 366 (2002)
The isomerization reaction of linoleic acid (cis-9,cis-12-octadecadienoic acid) to conjugated linoleic acids (CLA) was studied. A new heterogeneously catalytic pathway was developed for synthesis of CLA at mild reaction conditions (80-120 deg C) over Ru/C and Ni/H-MCM-41 catalysts in a diluted system. The isomerization reaction was tested in 1-octanol and n-decane. Solvents with low polarity were selected to afford good reactant adsorption on the catalyst surface and a high solvent-to-reactant ratio was used to prevent potential side reactions. Catalyst characterization was done by X-ray powder diffraction, X-ray fluorescence, X-ray photoelectron spectroscopy, hydrogen temperature-programmed desorption, direct current plasma atomic emission spectrometry, and BET techniques. The reactions taking place were isomerization of linoleic acid C18:2, hydrogenation of C18:2 acids to C18:1 monounsaturated octadecenoic acids (oleic acid, elaidic acid, cis-vaccenic acid and trans-vaccenic acid), and further hydrogenation of C18:1 acids to C18:0 stearic acid (n-octadecanoic acid) where isomerization and hydrogenation were two competing parallel reactions. The isomerization reaction was enhanced by preactivation of the catalysts under hydrogen, but such a treatment also increased the side reaction double-bond hydrogenation.
Synthesis of phosphatidylcholine with conjugated linoleic acid and studies on its cytotoxic activity
Niezgoda, Natalia,Mitula, Pawel,Kempinska, Katarzyna,Wietrzyk, Joanna,Wawrzenczyk, Czeslaw
, p. 354 - 361 (2013)
Phospholipids with conjugated linoleic acid (CLA), which are potential lipid prodrugs, were synthesised. CLA was obtained by the alkali-isomerisation of linoleic acid and was subsequently used in the synthesis of 1,2-di(conjugated)linoleoyl-sn-glycero-3-phosphocholine in good (82%) yield. 1-Palmitoyl-2-(conjugated)linoleoyl-sn-glycero-3-phosphocholine was obtained by a two-step synthesis in 87% yield. All the compounds were tested in an in vitro cytotoxicity assay against two human cancer cell lines, HL-60 and MCF-7, and a mouse fibroblast cell line, Balb/3T3. The free form of CLA exhibited the highest activity against all cancer cell lines. Results obtained for the Balb/3T3 line proved that phosphatidylcholine derivatives decreased the cytotoxic effect of CLA against healthy cell lines.
Method For The Production Of Conjugated Polyunsaturated Fatty Acids With Heterogenous Catalysts
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Paragraph 0105, (2013/09/26)
The present invention relates to an improved process for the production of conjugated polyunsaturated fatty acids (PUFA), preferably conjugated linoleic acid (CLA), using finely dispersed heterogeneous metal catalysts on a mesoporous support, in the absence of Hg. The present invention also relates to a method to increase the large microporosity and (optionally) the small mesoporosity of a zeolite, thus obtaining a modified zeolite having a large and highly accessible internal surface.
Sustainable and efficient methodology for CLA synthesis and identification
Moreno, Maria,Gomez, M. Victoria,Cebrian, Cristina,Prieto, Pilar,De La Hoz, Antonio,Moreno, Andres
, p. 2584 - 2594 (2013/02/23)
Microwave-assisted organic synthesis and continuous-flow techniques have been successfully employed for the preparation of conjugated linoleic acids (CLA), compounds with high health beneficial effects. A good production rate of CLA was obtained. A sustainable methodology for the differentiation of both positional and geometrical CLA isomers (diene), based on the analysis by NMR spectroscopy of the resulting Diels-Alder cycloadducts with an appropriate dienophile, was developed.
Probing lipid peroxidation by using linoleic acid and benzophenone
Andreu, Inmaculada,Neshchadin, Dmytro,Rico, Enrique,Griesser, Markus,Samadi, Abdelouahid,Morera, Isabel M.,Gescheidt, Georg,Miranda, Miguel A.
scheme or table, p. 10089 - 10096 (2011/10/13)
A thorough mechanistic study has been performed on the reaction between benzophenone (BZP) and a series of 1,4-dienes, including 1,4-cyclohexadiene (CHD), 1,4-dihydro-2-methylbenzoic acid (MBA), 1,4-dihydro-1,2-dimethylbenzoic acid (DMBA) and linoleic acid (LA). A combination of steady-state photolysis, laser flash photolysis (LFP), and photochemically induced dynamic nuclear polarization (photo-CIDNP) have been used. Irradiation of BZP and CHD led to a cross-coupled sensitizer-diene product, together with 6, 7, and 8. With MBA and DMBA as hydrogen donors, photoproducts arising from cross-coupling of sensitizer and diene radicals were found; compound 7 was also obtained, but 6 and o-toluic acid were only isolated in the irradiation of BZP with MBA. Triplet lifetimes were determined in the absence and in the presence of several diene concentrations. All three model compounds showed similar reactivity (k q≈108 M-1 s-1) towards triplet excited BZP. Partly reversible hydrogen abstraction of the allylic hydrogen atoms of CHD, MBA, and DMBA was also detected by photo-CIDNP on different timescales. Polarizations of the diamagnetic products were in full agreement with the results derived from LFP. Finally, LA also underwent partly reversible hydrogen abstraction during photoreaction with BZP. Subsequent hydrogen transfer between primary radicals led to conjugated derivatives of LA. The unpaired electron spin population in linoleyl radical (LA.) was predominantly found on H(1-5) protons. To date, LA-related radicals were only reported upon hydrogen transfer from highly substituted model compounds by steady-state EPR spectroscopy. Herein, we have experimentally established the formation of LA. and shown that it converts into two dominating conjugated isomers on the millisecond timescale. Such processes are at the basis of alterations of membrane structures caused by oxidative stress. Copyright
Superior anticarcinogenic activity of trans, trans-conjugated linoleic acid in N-methyl-N-nitrosourea-induced rat mammary tumorigenesis
Islam, Mohammad A.,Kim, Young S.,Oh, Tae W.,Kim, Gon S.,Won, Chung K.,Kim, Hoon G.,Choi, Myung S.,Kim, Jeong O.,Ha, Yeong L.
experimental part, p. 5670 - 5678 (2011/08/05)
The anticarcinogenic activity of a mixture of trans,trans-conjugated linoleic acid (trans,trans-CLA) was investigated in rat mammary tumorigenesis induced by N-methyl-N-nitrosourea (MNU), with references to cis-9,trans-11-CLA and trans-10,cis-12-CLA isomers. Female, 7-week-old Sprague-Dawley rats were intraperitoneally injected with MNU (50 mg/kg of body weight) and then subjected to one of five diets (control, 1% trans,trans-CLA, 1% cis-9,trans-11-CLA, 1% trans-10,cis-12-CLA, and 1% linoleic acid; 8 rats/group) for 16 weeks. Food and water were made available ad libitum. trans,trans-CLA significantly (p 0.05) reduced tumor incidence, number, multiplicity, and size and significantly (p 0.05) increased apoptosis, relative to cis-9,trans-11-CLA and trans-10,cis-12-CLA. The molecular mechanism of trans,trans-CLA was elucidated by measuring apoptosis-related gene products and fatty acid composition in tumors. trans,trans-CLA led to increases in the p53 protein and Bax protein levels but suppressed the expression of Bcl-2 protein. The activation of caspase-3 led to the cleavage of poly(ADP-ribose) polymerase, which resulted in the execution of apoptosis. In addition, trans,trans-CLA reduced cytosolic phospholipase A2, cyclooxygenease-2, and peroxisome proliferator-activated receptor γ protein levels. These results suggest that the trans,trans-CLA inhibits MNU-induced rat mammary tumorigenesis through the induction of apoptosis in conjunction with the reduction of arachidonic acid metabolites and that the efficacy of trans,trans-CLA is superior to cis-9,trans-11-CLA and trans-10,cis-12-CLA.
