Jinxing Long

SO3H-functionalized ionic liquid: efficient catalyst for bagasse liquefaction.

Liquefaction is a process for the production of biofuel or value-added biochemicals from non-food biomass. SO(3)H-, COOH-functionalized and HSO(4)-paired imidazolium ionic liquids were shown to be efficient catalysts for bagasse liquefaction in hot compressed water. Using SO(3)H-functionalized ionic liquid, 96.1% of bagasse was liquefied and 50.6% was selectively converted to low-boiling biochemicals at 543 K. The degree of liquefaction and selectivity for low-boiling products increased and the average molecular weight of the tetrahydrofuran soluble products decreased with increasing acidic strength of ionic liquids. Analysis of products and comparative characterization of raw materials and residues suggested that both catalytic liquefaction and hydrolysis processes contribute to the high conversion of bagasse. A possible liquefaction mechanism based on the generation of 3-cyclohexyl-1-propanol, one of the main products, is proposed.

Simultaneous delignification and selective catalytic transformation of agricultural lignocellulose in cooperative ionic liquid pairs

Catalytic transformation of readily available widely distributed and renewable non-food lignocelluloses to value-added chemicals has been recognized as an efficient approach for the alleviation of the increasing energy crisis and climate change. An efficient catalytic transformation process for agricultural residual lignocelluloses in cooperative ionic liquid pairs was achieved. The promotion of the dissolution equilibrium, combined with rapid, in situ acid-catalyzed degradation of cellulose and hemicellulose, resulted in significantly greater conversion of the biomass to biochemicals and selective delignification through further comparative analyses of the raw materials, products and residues by GC-MS, GPC, FT-IR, SEM and elemental characterization.

One step catalytic conversion of cellulose to sustainable chemicals utilizing cooperative ionic liquid pairs

A 100% conversion of cellulose to industrially useful chemicals is, for the first time, achieved in a single pot reaction by the use of cooperative ionic liquid pairs for combined dissolution and catalytic degradation of cellulose, which overcomes the long intrinsic phase problem in the conversion of biomass to chemicals.

Organosolv liquefaction of sugarcane bagasse catalyzed by acidic ionic liquids

An efficient and eco-friendly process is proposed for sugarcane bagasse liquefaction under mild condition using IL catalyst and environmental friendly solvent of ethanol/H2O. The relationship between IL acidic strength and its catalytic performance is investigated. The effects of reaction condition parameters such as catalyst dosage, temperature, time and solvent are also intensively studied. The results show that ethanol/H2O has a significant promotion effect on the simultaneous liquefaction of sugarcane bagasse carbohydrate and lignin. 97.5% of the bagasse can be liquefied with 66.46% of volatile product yield at 200°C for 30min. Furthermore, the IL catalyst shows good recyclability where no significant loss of the catalytic activity is exhibited even after five runs.

Catalytic Conversion of Carbohydrates to Levulinate Ester over Heteropolyanion‐Based Ionic Liquids

An efficient one-pot approach for the production of levulinate ester from renewable carbohydrates is demonstrated over heteropolyanion-based ionic liquid (IL-POM) catalysts with alcohols as the promoters and solvents. The relationships between the structure, acidic strength, and solubility of the IL-POM in methanol and the catalytic performance were studied intensively. A cellulose conversion of 100u2009% could be achieved with a 71.4u2009% yield of methyl levulinate over the catalyst [PyPS]3 PW12 O40 [PyPS=1-(3-sulfopropyl)pyridinium] at 150u2009°C for 5u2005h. This high efficiency is ascribed to the reasonably high activity of the ionic liquid (IL) catalyst and reaction coupling with rapid inu2005situ esterification of the generated levulinic acid with the alcohol promoter, which allows the insolubility of cellulose encountered in biomass conversion to be overcome. Furthermore, the present process exhibits high feedstock adaptability for typical carbohydrates and handy catalyst recovery by a simple self-separation procedure through temperature control.

Which is the determinant for cellulose degradation in cooperative ionic liquid pairs: dissolution or catalysis

Catalytic conversion of sustainable cellulose to the value-added chemicals and high quality biofuel has been recognized as a perfect approach for the alleviation of the dependence on the non-renewable fossil resources. Previously, we successfully designed and explored novel and efficient cooperative ionic liquid pairs for this renewable material, which has advantages of high reactor efficiency than current technologies because of the dissolution and in situ catalytic decomposition mechanism. Here, the determinant of this process is further studied by the intensive investigation on the relationship between the cellulose conversion and the properties of ionic liquid catalyst and solvent. Scanning electron microscope (SEM), thermogravimetric analysis (TG) and elemental analysis were used for the comparative characterization of raw cellulose and the residues. The results demonstrate that this consecutive dissolution and in situ catalysis process is much more dependent on the dissolution capability of ionic liquid solvent, while comparatively, the effect of in situ acid catalysis is relatively insignificant.

Selective depolymerization of lignosulfonate via hydrogen transfer enhanced in an emulsion microreactor

An efficient emulsion microreactor was constructed for selective conversion of lignosulfonate via hydrogen transfer reaction based on the self-surfactivity of this natural aromatic polymer. Industrial Raney Ni and isopropanol were used as catalyst and hydrogen donor, respectively. The results showed that the emulsion microreactor has a remarkable process intensification effect on the lignosulfonate depolymerization. Under mild condition of 473u202fK for 2.0u202fh, 116.1u202fmgu202fg-1 of volatile phenolic monomer can be obtained, which is twice of that from other investigated processes without emulsion of this work. In particular, 39.3u202fmgu202fg-1 of which is composed of 4-ethyl guaiacol, an important and versatile chemical currently from petrochemical industry. Furthermore, the solvent separates to two phases automatically after reaction due to the consumption of lignosulfonate, which makes handy products enrichment and separation. Additionally, the emulsion microreactor is significantly affected by hydrogen donor and is efficient for other lignin sources as well.

Selective catalytic tailoring of the H unit in herbaceous lignin for methyl p-hydroxycinnamate production over metal-based ionic liquids

Selective valorization of lignin to achieve high value and commodity chemicals is attracting increasing attention. In this work, an efficient and reusable metal-based ionic liquid (MBIL) was developed for the selective tailoring of p-coumaric acid ester (pCA), a typical p-hydroxyphenyl (H) unit, into methyl p-hydroxycinnamate (MPC). Under optimized conditions and in the presence of catalyst [Bmim][FeCl4], a volatile aromatic product of 10.5 wt% was obtained, of which, 70.5% separated as pure MPC with an isolated yield of 71.1 mg g−1. FT-IR, 13C NMR, ANO and 2D HSQC demonstrated that the H unit was preferentially tailored from lignin, of which, 86.0 wt% of the H structure unit is cut off from lignin, with 70.6% being selectively converted to MPC. Further investigation demonstrated that MBIL prefers to tailor ester bonds compared to ether bonds using model compounds, and the superior catalytic ester bond cleavage performance exhibited by [Bmim][FeCl4] can be ascribed to the relatively narrow energy gap between the lignin ester bond and [FeCl4]− anion and to the comparatively low absolute binding energy between the cation and anion through DFT calculations.

Catalytic conversion of duckweed to methyl levulinate in the presence of acidic ionic liquids

In this study, an efficient strategy is proposed for selective methyl levulinate production from duckweed, a typical fast-growing aquatic microalgae in warm and humid regions, in the presence of acidic ionic liquids (ILs). The results show that IL structure has a significant effect on its acidic strength, which finally determines the process efficiency for levulinate methyl generation. With the optimized catalyst of [C3H6SO3HPy]HSO4, 88.0% duckweed is consumed, resulting in a comparable methyl levulinate yield of 73.7% and a process efficiency of 81.8% at 170u202f°C for 5u202fh. Furthermore, this process is substantially influenced by the reaction condition, particularly, it is significantly temperature-dependent. In addition, solvent has a remarkable intensified effect on the process efficiency, which dramatically decreases from 81.8 to 53.7% when methanol is replaced by water.