Grafting Of Ionic Liquid Research Articles

Ionic liquid/Mn complex immobilized on phenylene based periodic mesoporous organosilica: An efficient and reusable nanocatalyst for green oxidation of alcohols

A novel bifunctional periodic mesoporous organosilica with ionic liquid and phenylene framework supported manganese (BPMO-Ph-IL/Mn) was synthesized, characterized and its catalytic application was investigated. The BPMO-Ph-IL/Mn nanocatalyst was prepared through grafting of ionic liquid on a phenylene based PMO followed by treatment with manganese nitrate. The designed BPMO-Ph-IL/Mn catalyst was characterized using FT-IR, PXRD, TEM, EDX and N2 adsorption–desorption analyses. This was used as an efficient catalyst for selective oxidation of different alcohols. The BPMO-Ph-IL/Mn catalyst was recovered and reused for at least five times without a significant decrease in its efficiency.

One-pot multicomponent synthesis of N-sulfonyl amidines using magnetic separable nanoparticles-decorated N-heterocyclic carbene complex with copper

Magnetic separable nanoparticles-decorated N-heterocyclic carbene complex with copper (MNP[1-Methyl benzimidazole]NHC@Cu) has been prepared by covalent grafting of ionic liquid like 1-methyl benzimidazole unit on the surface of chlorofunctionalized Fe3O4 magnetic nanoparticles (MNPs) followed by metallation with copper(I) iodide. MNP[1-Methyl benzimidazole]NHC@Cu complex has been characterized by different techniques including Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), energy-dispersive X-ray (EDX) analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). MNP[1-Methyl benzimidazole]NHC@Cu complex was successfully implemented as heterogeneous catalyst in one-pot multicomponent synthesis of N-sulfonyl amidines from phenylacetylene, tosyl azide and amines at room temperature. Complex could be recycled six times without significant loss in the yield of product.

Magnetic ethyl-based mesoporous organosilica composite supported IL/Mn: A novel and highly recoverable nanocatalyst for preparation of 4H-pyrans

A novel magnetic bifunctional ethyl-based periodic mesoporous organosilica supported ionic liquid/manganese complex (Mag-BPMO/Mn) with core–shell structure was synthesized and characterized. The Mag-BPMO/Mn was prepared via grafting of ionic liquid on magnetic Et-based PMO followed by treatment with Mn(NO3)2•4H2O. The physiochemical properties of this nanocatalyst was studied by using Fourier transform infrared (FT-IR) spectroscopy, low angle powder X-ray diffraction (LAPXRD), wide-angle PXRD, energy-dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) analyses. The Mag-BPMO/Mn was applied as an efficient and reusable heterogeneous nanocatalyst for green synthesis of 4H-pyran derivatives via a one‐pot three‐component reaction. The effect of several parameters such as catalyst loading and solvent were investigated in the catalytic process. The recoverability and reusability of the designed Mag-BPMO/Mn nanocatalyst were also studied under applied conditions.

Bentonite with high loading of ionic liquid: A potent non-metallic catalyst for the synthesis of dihydropyrimidinones

In attempt to devise an environmentally-benign metal-free catalyst, ionic liquid was supported on bentonite that is a natural clay. To enhance the loading of ionic liquid, bentonite was first functionalized with a dendritic moiety through successive reactions with 2,4,6-trichloro-1,3,5-triazine and 1,3-diaminopropane. Then, the terminal functionalities of dendron were adorned with ionic liquids via reaction with 1-methyl imidazole. The study of the catalytic activity of the resultant catalyst for promoting Biginelli reaction in aqueous media under mild reaction condition approved high activity of the designed composite, superior to that of bentonite. To investigate the role of ionic liquid content in the activity of the catalyst, two model catalysts were prepared through immobilization of ionic liquid on bentonite and bentonite decorated with dendron of lower generation. It was found that the presence of the dendritic moiety could increase grafting of ionic liquid on bentonite and consequently improve the catalytic activity of final catalyst. Notably, the catalyst was highly recyclable. Moreover, analysis of the recycled catalyst indicated the stability of the catalyst.

Adsorption/desorption of 2,2,4-trimethylpentane on MCM-36 zeolite functionalized by acidic ionic liquid

The facile desorption of products from the reaction sites is crucial to the reaction selectively and catalyst life. In the alkylation process of isobutane and olefine, the product is need to remove from the reaction sites timely so as to inhibit the sequential side reactions and improve the catalyst life. MCM-36 was modified by immobilizing ionic liquid [BTPIm][HSO4] (1-buty-3-(3-triethoxysilane)-propyl imidazolium hydrosulfate) so as to provide an effective way to improve the desorption of product 2,2,4-trimethylpentane from the reaction sites. The adsorption/desorption behaviors of 2,2,4-trimethylpentane on MCM-36 or ionic liquid immobilized MCM-36 were studied systematically by an intelligent gravimetric analyzer. The results showed that a decease adsorption capacity of 2,2,4-trimethylpentane was obtained after grafting [BTPIm][HSO4]. Langmuir–Freundlich model described the adsorption isotherms well. The ionic liquid immobilization led to a low isosteric adsorption heat. It indicated that a weaken interaction between adsorbate and adsorbent was obtained by the grafting of ionic liquid. The kinetics research results showed that the adsorption/desorption process was limited by the surface adsorption step. An increase of desorption rate constant and a decrease of adsorption sites were observed after the IL immobilization. It suggested that the ionic liquid loading was helpful to improve the desorption of 2,2,4-trimethylpentane from the reaction surface.

Local Grafting of Ionic Liquid in Poly(vinylidene fluoride) Amorphous Region and the Subsequent Microphase Separation Behavior in Melt.

Polymer-based nanostructures can be generally created by self-assembly of block copolymers that are commonly synthesized by living radical polymerization. In this study, a new strategy is proposed to fabricate block-like copolymers by using the template of binary phase structure of semicrystalline polymers. Poly(vinylidene fluoride) (PVDF) is thermodynamically miscible with an unsaturated ionic liquid (IL) (1-vinyl-3-ethylimidazolium tetrafluoroborate) in the melt and IL molecules are expelled out from the crystalline parts during the crystallization of PVDF. Therefore, the IL molecules are only located at the amorphous region of PVDF crystals. The electron beam irradiation of the IL incorporated PVDF leads to the local grafting of IL molecules onto the PVDF molecular chains in the amorphous region, so block-like grafting polymer chains of crystalline PVDF-b-(amorphous PVDF-g-IL)-b-crystalline PVDF can be achieved. The subsequent heating of the irradiated sample induces the microphase separation of PVDF-g-IL from the ungrafted PVDF chains.

PdNP Decoration of Halloysite Lumen via Selective Grafting of Ionic Liquid onto the Aluminol Surfaces and Catalytic Application.

The synthesis of selectively deposited palladium nanoparticles (PdNPs) inside tubular halloysite lumens is reported. This specific localization was directed by the selective modification of the aluminol surfaces of the clay mineral through stable Al-O-C bonds. An ionic liquid (1-(2-hydroxyethyl)-3-methylimidazolium) was grafted onto halloysite following the guest displacement method (generally used for kaolinite) using halloysite-DMSO preintercalate. The characterization of this clay nanohybrid material (XRD, NMR, TGA) showed characteristics reminiscent of similar materials synthesized from kaolinite. The grafting on halloysite lumens was also effective without using the DMSO preintercalate. The presence of these new functionalities in halloysite directs the synthesis of uniform PdNPs with size ranging between 3 and 6 nm located exclusively in the lumens. This results from the selective adsorption of PdNPs precursors in functionalized lumens through an anion exchange mechanism followed by in situ reduction. In contrast, the unmodified clay mineral displayed nanoparticles both inside and outside the tubes. These catalysts showed significant catalytic activity for the reduction of 4-nitrophenol (4-NP). The most efficient catalysts were recycled up to three times without reducing significantly the catalytic activities.

Grafting of ionic liquids on stainless steel surface for antibacterial application

Stainless steel (SS) is favored for many uses due to its excellent chemical resistance, thermal stability and mechanical properties. Biofilms can be formed on stainless steel and may lead to serious hygiene problems and economic losses in many areas, e.g. food processing, public infrastructure and healthcare. For the first time, our work endeavored to make SS having antibacterial properties, ionic liquids (ILs) were grafted on SS surface via silane treatment followed by thiol-ene click reaction. The chemical structure and composition of the ILs grafted stainless-steel coupon surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. The antibacterial activity has been investigated, and the results showed that the ILs grafted SS surface exhibited significant antibacterial effects against Gram-negative Escherichia coli. Additionally, the results obtained here indicated that the ILs used here having bromide anion showed much better antibacterial activity against E. coli than the corresponding ILs with tetrafluoroborate and hexafluorophosphate as anions. These results obtained here can help to design novel and more efficient stainless steel having antibacterial surface.

Effects of silica nanoparticle supported ionic liquid as additive on thermal reversibility of human carbonic anhydrase II

Silica nanoparticle supported imidazolium ionic liquid [SNImIL] was synthesized and utilized as a biocompatible additive for studying the thermal reversibility of human carbonic anhydrase II (HCA II). For this purpose, we prepared additive by modification of nanoparticles through the grafting of ionic liquids on the surface of nanoparticles (SNImIL). The SNImIL were fully characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and thermo gravimetric analysis. The characterization of HCA II was investigated by various techniques including UV–vis and ANS fluorescence spectrophotometry, differential scanning calorimetry, and docking study. SNImIL induced disaggregation, enhanced protein stability and increased thermal reversibility of HCA II by up to 42% at pH 7.75.