C18:1 Methyl Ester Metathesis in [bmim][X] Type Ionic Liquids

Abstract

The efficacy of [bmim][X] ionic liquids (ILs) (X = PF6−, BF4− and NTf2−) as reaction media for methyl oleate metathesis was compared with that of conventional organic solvents (PhCl, PhMe, DCM and DCE) using the well-defined first and second generation Grubbs precatalysts, RuCl2(PCy3)(L)(=CHPh) (L = PCy3 or H2IMes). Best catalytic performance, with excellent selectivity (>98%) at moderate reaction temperatures, was achieved in [bmim][X] ILs compared to conventional solvents. The effects of anion, reaction temperature, solvent polarity, solvent viscosity, and ligand-anion interaction on the reaction are also addressed.

Fatty acid methyl ester heterogeneous self‐metathesis in hydrophobic green solvent: Mass transfer limitations, catalyst recyclability, and stability

“…Further increase in reaction time up to 60 min was accompanied by a small decrease in the methyl elaidate concentration before levelling‐off or even slightly declining to a final concentration of 25.5 μmol mL −1 (Figure a). This slight depletion of methyl elaidate could be due to its reaction by self‐ metathesis and/or cross‐metathesis with methyl oleate or primary metathesis products yielding secondary metathesis products (SMP) as reported by Thomas and Marvey . In all cases, the major PMPs are trans‐9‐octadecene and trans‐dimethyl‐9‐octadecene‐1,18‐dioate for the reaction media tested.…”

“…This slight depletion of methyl elaidate could be due to its reaction by selfmetathesis and/or cross-metathesis with methyl oleate or primary metathesis products yielding secondary metathesis products (SMP) as reported by Thomas and Marvey. [24] In all cases, the major PMPs are trans-9-octadecene and trans-dimethyl-9-octadecene-1,18-dioate for the reaction media tested. It is worth mentioning that the trans-products outweighed the cis-counterparts, in all cases.…”

“…The products 1, 2, 4, and 5 were formed via a productive metathesis pathway, whereas the product 3 (methyl elaidate) was formed via a non-productive metathesis pathway which is a parallel unwanted side reaction. [8,9,23] The unknown products could be due to the implication of PMPs in secondary metathesis reaction mainly crossmetathesis [24] or obtained by other type of reactions occurring concomitantly, such as isomerization, dimerization, or polymerization. These unknown products attained only a maximum value of $10 mmol mL À1 and afterwards were continuously exhausted over the time.…”

Room Temperature Ionic Liquids as Green Solvent Alternatives in the Metathesis of Oleochemical Feedstocks

“…The cation of the IL is generally a bulk organic structure with low symmetry. The most popularly used cations are ammonium ( 7a ) [34,35,36], phosphonium ( 7b ) [37], sulphonium ( 7c ) [38], imidazolium ( 7d ) [39,40,41,42,43], pyridinium 7e ) [44,45,46], pyrrolidinium ( 7f ) [47], thiazolium ( 7g ) [48], triazolium ( 7h ) [49], oxazolium ( 7i ) [50] and pyrazolium ( 7j ) [51] cations (Figure 4). The most commonly used ILs are the salts based on the N , N′ -dialkylimidazolium cation ( 7d ).…”

RTILs in Catalytic Olefin Metathesis Reactions

“…In 2009, the group of B. Marvey in South Africa evaluated the interest of RTILs for the self-metathesis of methyl oleate using the Grubbs 1st and 2nd generation catalysts C1 and C2 [50] C. In all cases the biphasic mixture led to conversions in the range 50-60% after 4 h with full selectivity towards the self-metathesis products 7 and 8 hence no major difference with regards to the counter anions was visible. Increasing the reaction temperature had a beneficial impact on the conversion but the selectivity decreased due to the formation of SMPs.…”