Conjugated linoleic acid formation by hydrogenation/isomerisation of safflower oil over bifunctional structured catalyst Rh/SBA‐15

Abstract

Directed isomerisation of safflower oil under very low hydrogen partial pressure of 7 psi over a novel bifunctional highly structured rhodium-based catalyst (Rh/SBA-15), having narrow pore size distribution ranging from 4 to 8 nm, and BET-specific surface of ≈1,000 m 2 g −1 , was investigated as a new chemocatalytic approach for vegetable oil hardening and simultaneously producing health-beneficial conjugated linoleic acids (CLA). Time course profiles of (cis-9, trans-11)-; (cis-10, trans-12)-; (trans-10, cis-12)-; (cis,cis)-and (trans, trans)-octadecadienoic isomers (CLAs) as well as the other fatty acids traditionally encountered during the hydrogenation of vegetable oils are presented and discussed under selected process conditions. Preliminary results show that it is possible to tailor characteristics of the hydrogenation catalyst in such way to confer its bi-functional activity: hydrogenation and conjugation isomerisation.

Sulfur Promotion in Conjugated Isomerization of Safflower Oil over Bifunctional Structured Rh/SBA‐15 Catalysts

“…Rh/SBA‐15 catalyst with 1 ppm sulfur addition exhibited favorable reaction features if safflower oil was partially hydrogenated ( IV =135 after 300 min of reaction) as shown by the low content of trans ‐C18:1 (only 8 %) and C18:0 (remained at 3 %). These results confirmed those reported in our previous work using other batches of rhodium,18, 19, 28 palladium,31, 32 and ruthenium as well as bimetallic catalysts supported on SBA‐15 33. From the standpoint of health and technical functional properties, these catalysts represent a good compromise between hydrogenation activity and capacity to lower trans and saturated fatty acids.…”

“…Starting from 1 %Rh/SBA‐15 bifunctional catalyst, which was reported to be an active catalyst for the hydrogenation/directed isomerization of vegetable oils,18, 19, 28 we next aimed to verify if any sulfur addition to the reaction medium could enhance the CLAs formation over this catalyst.…”

“…We also revealed that the optimization of the operating conditions improved the conjugated isomerization activity of Rh/SBA‐15 at the expense of cis–trans geometric isomerization activity during the partial hydrogenation of safflower oil 18. 19…”

“…%, was revealed as a new active catalyst for the chemocatalytic conversion of vegetable oils to CLAs during the hydrogenation/directed isomerization process 18. 19 We particularly showed that it is possible to tailor characteristics of the hydrogenation catalyst in such a way to confer its bi‐functional activity: hydrogenation and conjugated isomerization. We also revealed that the optimization of the operating conditions improved the conjugated isomerization activity of Rh/SBA‐15 at the expense of cis–trans geometric isomerization activity during the partial hydrogenation of safflower oil 18.…”

Application of Rh/MWCNT catalysts in the preparation of conjugated linoleic acid from linoleic acid

“…Nickel-based catalysts require higher reaction temperatures and have specific toxicity (Thunyaratchatanon et al, 2016). In contrast, the Rh-based catalyst has a good catalytic effect (Chorfa et al, 2012;Kim et al, 2015).…”