Direct Isomerization of Linoleic Acid to Conjugated Linoleic Acids (CLA) using Gold Catalysts

Bauer, Peter; Horlacher, Peter; Claus, Peter

doi:10.1002/ceat.200900384

Cited by 15 publications

(7 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The linoleic acid conversion increased with the reaction temperature, while the physiologically important c-9,t-11 and t-10,c-12 isomers always remained the main components of the products. Similar results were found using supported gold catalysts in the presence of hydrogen at 165 °C in a batch reactor (BAUER et al, 2009).…”

Section: Synthesis Of Clas With Heterogeneous Catalysissupporting

confidence: 84%

“…By utilizing the main advantage of heterogeneous catalysts, i.e., the easy catalyst/product separation, this type of catalyst can be used in a continuous process in a fi xed-bed reactor or a continuous stirred tank reactor (BAUER et al, 2009;PHILIPPAERTS et al, 2011). For the isomerisation of alkyl linoleates to obtain CLAs, several metals (Ni, Ru, Rh) on various supports were used (DESHPANDE et al, 1985).…”

Section: Obtaining Of Clas From Linoleic Acid Alkyl Linoleates and Tmentioning

confidence: 99%

See 1 more Smart Citation

Synthetic methods to obtain conjugated linoleic acids (CLAs) by catalysis – A review

Salamon¹,

Vargáné-Visi²,

András³

et al. 2015

Acta Alimentaria

View full text Add to dashboard Cite

The addition of synthetic CLA is a possible way in order to compose foods enriched with conjugated linoleic acids (CLAs). The most environmental friendly methods for CLA synthesis are based on microbial biosynthesis. With homogeneous catalysis using organometallic catalysts (Ru and Rh complexes) high (approximately 80%) yields were obtained with high selectivity related to bioactive isomers. The heterogeneous catalysis has the advantage that at the end of the reaction there is no need for a supplementary separation operation or recycling of the catalyst. In heterogeneous process, the maximum yield may even be higher than 90% and the selectivity remains quite high as the reaction conditions are optimized. The substrates for obtaining CLAs are, in general, linoleic acid or alkyl linoleates and the catalysis is acidic. The yield and the selectivity depend on the strength and the type of acidic sites, as well as on the size distribution of the particles. Beside the existing catalytic methods, a photocatalytic process with UV and visible light irradiation with iodine promoter can be applied.Keywords: conjugated linoleic acid, CLA, homogeneous catalysis, heterogeneous catalysis, photocatalytic process Recently many new health-benefi t effects of the conjugated linoleic acids (CLAs) were discovered. They decrease the body fat quantity and increase muscle mass, possess antiinfl ammatory and cancer preventive effects, exert benefi cial effects on the skeletal system, act as immunostimulants, and decrease the probability of asthma occurrence (HA et al., 1989;PARIZA et al., 2001).Theoretically 56 isomers exist, however, few of them (cis(c)-9,trans(t)-11; t-10,c-12-and t-9,t-11 CLA) have been shown to have signifi cant biologic activity. The bioactivity of the c-9,t-11 CLA isomer (Fig. 1) was discovered two decades ago (HA et al., 1989) and this isomer is predominant in the natural products used as foods. The main foods rich in CLA are milk, dairy products, meat and fat of the ruminants, as this isomer is produced by the bacteria of the rumen microfl ora.Nowadays, CLAs are obtained for industrial purpose from vegetable oils that are processed at high temperature (PHILIPPAERTS et al., 2011). The basic method in the industrial approach is the isomerisation of linoleic acid (LA) with basic catalysis by which the amounts of the two formed isomers (c-9,t-11 and t-10,c-12 CLA) are almost equal, and the yield is quite high. This synthetic method cannot be applied for the direct transformation of vegetable oils into CLA-rich triacylglycerols, because ester bonds of triacylglycerols hydrolyze to free fatty acids (or salts) and glycerol.

show abstract

Section: Synthesis Of Clas With Heterogeneous Catalysissupporting

confidence: 84%

Section: Obtaining Of Clas From Linoleic Acid Alkyl Linoleates and Tmentioning

confidence: 99%

Synthetic methods to obtain conjugated linoleic acids (CLAs) by catalysis – A review

Salamon¹,

Vargáné-Visi²,

András³

et al. 2015

Acta Alimentaria

View full text Add to dashboard Cite

show abstract

“…Except the CLA yield, the selectivity, that is, the content of desirable CLA isomers (cis-9, trans11 and trans-10, cis-12) was also the target. The current major applied processes include alkali isomerization (Berdeaux et al, 1998;Da Porto et al, 2012;Goli et al, 2008;Kim et al, 2000;Liu et al, 2019;Ma et al, 1999;Nagao et al, 2003;Wang et al, 2013;Yang and Liu, 2004), which is the current most applied industrial process, and catalytic conjugation catalyzed by VIII Group metals (Bauer et al, 2009;Bernas and Murzin, 2003;Kreich and Supporting information Additional supporting information may be found online in the Supporting Information section at the end of the article. Claus, 2005;Larock et al, 2001) (Liu et al, 2019), as well as enzymatic conversion of LNA (Lin, 2000;Zhang et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

A Soap‐Free Strategy for One‐Pot Synthesizing Conjugated Linoleic Acid: Alkali Isomerization of Linoleic Acid through Preferential Esterification Pathway

San

Fan

Fang

et al. 2020

J Americ Oil Chem Soc

View full text Add to dashboard Cite

Conjugated linoleic acid (CLA) exhibits beneficial biological activities but possesses poor natural abundance, which is usually obtained by alkali isomerization of linoleic acid (LNA). The one‐pot alkali isomerization consists two reactions, firstly saponifying LNA and then isomerizing linoleate. This current process has been limited by two drawbacks, the overconsumption of both alkali and solvent, as well as the weak mass/heat transfer of the viscous paste of reaction mixture that limits the synthesis scale. The present study alternated the reaction pathway with a soap‐free preferential esterification pathway, that is, firstly employing slight NaOH to induce the esterification of LNA and diol (the reaction solvent), then conducting alkali isomerization of the intermediate alkyl linoleate instead of sodium linoleate. In this developed one‐pot procedure, a CLA yield of 90% and the selectivity of the desired isomers (“c9, t11” and “t10, c12” CLA) of 82.4% were obtained; and it reduced the consumption of NaOH and the solvent by 60% and 25% comparing to the current soap pathway, respectively; Yet the result is comparative to that obtained with assistant of microwave/ultrasound in even longer reaction time. In this way, the two drawbacks can be overcome and the green characteristics of the current process was well kept.

show abstract

“…These two research groups also investigated the use of gold catalysts supported in a wide variety of supports, such as Al 2 O 3 , SiO 2 , Fe 2 O 3 , CeO 2 , MnO 2 , TiO 2 , ZrO 2 , active carbon, and Ti-silicalite (TS-1), but the results did not improve those previously obtained [15,16]. Au increased activity but favoured the formation of undesired hydrogenation products.…”

Section: Introductionmentioning

confidence: 99%

Layered Double Hydroxides for the Catalytic Isomerization of Linoleic Acid to Conjugated Linoleic Acids (CLAs)

2019

View full text Add to dashboard Cite

Several hydrotalcite-type compounds with different divalent (Mg2+, Ni2+, Cu2+, Zn2+) and trivalent (Al3+, Cr3+) cations and different ratio compositions were tested for the isomerization of linoleic acid in order to study their role on the obtention of specific conjugated linoleic acids (CLAs) with anticarcinogenic and nutritional properties. This is a complex reaction due to the high number of possible isomers of linoleic acid together with the significant competition of the isomerization reaction with other secondary undesired reactions. All catalysts showed very high conversions of linoleic acid, but condensation products were mainly obtained, especially for the hydrotalcite-type compounds with higher Mg/Al ratios due to their higher Brønsted basicity and for the catalysts with higher Ni2+ content or with the presence of Cu2+, Zn2+ in the layers because of the influence of the higher acidity of these cations on the Brønsted basicity of the hydroxides. The best results were achieved for the catalysts with Mg/Al ratio around 2.5–3, resulting in 29–38% of selectivity to the identified CLAs.

show abstract

Direct Isomerization of Linoleic Acid to Conjugated Linoleic Acids (CLA) using Gold Catalysts

Cited by 15 publications

References 43 publications

Synthetic methods to obtain conjugated linoleic acids (CLAs) by catalysis – A review

Synthetic methods to obtain conjugated linoleic acids (CLAs) by catalysis – A review

A Soap‐Free Strategy for One‐Pot Synthesizing Conjugated Linoleic Acid: Alkali Isomerization of Linoleic Acid through Preferential Esterification Pathway

Layered Double Hydroxides for the Catalytic Isomerization of Linoleic Acid to Conjugated Linoleic Acids (CLAs)

Contact Info

Product

Resources

About