Search

Methyl linolenate (C18-3) is a type of unsaturated fatty acid methyl ester with high biological activity. Membrane separation of C18-3 from tallow seed oil methyl ester by supported ionic liquids membranes (SILM) containing carrier Ag+ was successfully achieved in this study. The interaction between Ag+ and C18-3 was explored by density functional theory (DFT). High selectivity to C18-3 was mainly due to the π/inverse π complexation interactions between Ag+ and C=C bonds. The effects of ionic liquid structure, carrier Ag+ concentration, adjacent phase flow rates and membrane pore size on permeability and selectivity to C18-3 were examined. The existence of 1-hexene in the stripping phase and carrier Ag+ can facilitate C18-3 transport. Good separation performance was achieved by the 0.45 μm nylon membrane impregnated with ionic liquid [BMIm]BF 4 containing AgBF 4. C18-3 was enriched from 16.7% in the feed phase to higher than 75% in the product. Moreover, adding a hydrophobic PVDF protective membrane to form a composite membrane was an effective method to increase the SILM stability and membrane lifetime by about twice compared with a single nylon membrane. • Ag+-based supported ionic liquid membrane was used to separate methyl linolenate.. • The action mechanism between Ag+ and methyl linolenate was explored by DFT. • Ag+ preferentially coordinated with C=C bond rather than C=O bond. • Hydrophilic/hydrophobic composite membrane could improve the membrane stability. • 1-hexene in the stripping phase and Ag+ can facilitate methyl linolenate transport. [ABSTRACT FROM AUTHOR]

The creation of a catalytic method that possesses high activity and effective reusability for the oxidative cleavage of vegetable oils and their derivatives to prepare bio-based oxo-chemicals is a challenge. This work introduces a “release and capture” catalytic system consisting of H2O2, WO3 and mesoporous SnO2. This system was intended to promote catalyst reusability in the oxidative cleavage of methyl 9,10-epoxystearate (ME) to the corresponding aldehydes. No organic solvent was used in the reaction. The reaction temperature, molar ratio of ME/WO3/H2O2, and reaction time were optimized to 70 °C, 1/0.017/1.3, and 20 min, respectively. Under these conditions, complete ME conversion and 80% aldehyde yield were obtained. The hot filtration experiment and ICP-MS analysis confirmed the leaching of tungsten. Mesoporous SnO2 did not affect the ME conversion and aldehyde yield, but effectively adsorbed the leached tungsten. The catalyst in this system showed no significant decrease in activity after being reused ten times. [ABSTRACT FROM AUTHOR]

Supported liquid membranes show great potential in the efficient separation of methyl linolenate from its analogues, but there still remain some critical challenges to further this technology towards larger application because of the slow transmembrane transport and poor stability of liquid membrane. Herein, 1,2-butanediol (1,2-BDO) with good solubility for AgBF 4 substitutes for ionic liquid as membrane solvent, and fabric reinforced hollow fiber composite membrane (PR-HFM) with higher mechanical strength and interfacial area replaces plate membrane as base support. A new supported liquid membrane has been prepared by coating the 1,2-BDO solution dissolving AgBF 4 on the surface of PR-HFM and embedding the solution into the micro-pores of PR-HFM by repeated pull with vacuum and push with N 2. The as-prepared liquid membranes exhibit good separation performance and stability. It can be safely and steadily used to treat the feed with fatty acid methyl esters (FAMEs) concentration lower than 150 mg/mL at the velocity of less than 0.22 m/s. Within 24 h continuous operation, methyl linolenate (C18-3) can pass steadily through the liquid membrane at the mean permeability larger than 3.13 × 10−7 m/s, the C18-3 product with the purity larger than 82% and the selectivity of C18-3 over C18-2 (S C18-3/C18-2) larger than 6.63 can be obtained steadily. [Display omitted] • A new supported liquid membrane was used to purify successfully methyl linolenate. • The as-prepared liquid membrane has good permeability rate and stability. • 1,2-butanediol was used as membrane solvent to improve the permeability rate. • Fabric reinforced hollow membrane was chosen as support to improve the stability. [ABSTRACT FROM AUTHOR]