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Sulfonated carbonaceous solid acids are key heterogeneous catalysts and are widely used in acid-catalyzed reactions, especially in biomass transformation. In this work, the sulfonated carbonaceous solid acids were prepared and their stability was examined in cellulose hydrolysis at 170 °C. Their activity decreased largely after the hydrothermal treatment at 170 °C, as a result of the leaching of their SO3H species. Characterizations of the filtrates after the hydrothermal treatment of these solid acid catalysts by NMR and laser scattering demonstrated that the leaching of SO3H sites was not caused by the cleavage of C S bonds, but by the exfoliation of colloidal carbon particles with SO3H sites from the catalysts. Such leaching problem led to significant decrease in SO3H density for the carbon-based solid acids that synthesized by traditional sulfonation methods because of their uneven distribution of SO3H sites. To address this issue, carbon precursors with more free C H sites were applied to regulate the distribution of SO3H sites. As a consequence, the evenly distributed SO3H sites resulted in less change in acid density after the hydrothermal treatment, and maintenance of high SO3H density. This study could provide new guidance to further design of water-tolerant solid acid catalysts, and would promote the development of energetically efficient processes to convert cellulose.

In this work, nickel metal supported on different supports (SiO2, Al2O3, ZSM-5) were prepared by spraying nickel nitrate on the supports and calcined at 873 K. Then, they were characterized by XRD, XRF, N2 adsorption–desorption, NH3-TPD, MCH-TPD, H2-TPR, and pyridine-FTIR, and tested as catalysts for the dehydrogenation aromatization and isomerization of methylcyclohexane (MCH) under the conditions of S-Zorb catalytic adsorption desulfurization (T = 673 K, P = 1.5 MPa, WHSV = 5 h−1). The H2-TPR results showed that the interaction of NiO with support decreased in the order of NiO/ZSM-5-Fe

Cellulose hydrolysis in dilute mineral acids was investigated, and a plateau in cellulose conversion was observed such that an extended reaction time did not result in further conversion of cellulose, which severely reduced the hydrolysis efficiency of cellulose. The characterization results indicated that the crystallinity indexes of cellulose and the deposition of humins were not the key factors inhibiting the reaction but rather the solation of cellulose in the presence of water, protons, and anions was the key. The hydrolysis reaction proceeded after the solated state of cellulose was disrupted by means of filtration, increased temperature, or the addition of organic solvents and inorganic salts. However, a new plateau in cellulose conversion eventually formed and inhibited the hydrolysis reaction again. Therefore, continuous disruption of the solated system of cellulose is the key strategy to achieve high cellulose conversion under even mild reaction conditions.

Hydrodeoxygenation of phenolic components in pyrolysis bio-oil is considered to be a potential strategy for producing renewable aromatic chemicals. The key issue of this process is the establishment of an effective catalytic system that can cleave the CAr–O bonds without affecting the aromatic structure. To achieve this goal, an efficient heterogeneous catalyst with solid acid support (WOx/ZrO2) and active metal (Ru) was prepared in this study. The Ru–WOx/ZrO2 catalyst can effectively convert model phenolic compounds into aromatic hydrocarbons. For a mixed phenolic sample, the conversion to and selectivity for arenes were all around 90%. The good selectivity was proved to be strongly related to the surface adsorption and acid properties of the catalyst as well as the reaction pathway. Moreover, the hydrodeoxygenation of a pretreated bio-oil was also conducted and presented a satisfactory yield of arenes at 240 °C with 1 MPa of H2 reacted for 5 h. The depolymerization of high-molecular-weight phenolic olig...

The catalytic behavior of a series of MFI catalysts with different Si/Al ratio (25–300) in the direct aqueous-phase hydrolysis of α-cellulose was studied. The effects ultrasonic pretreatment time, ZnCl2 content, zeolite pore structure and acid-basic properties on catalyst activity and products distribution were systematically investigated. The results indicated that HZSM-5 with lower Si/Al ratio was beneficial for production of glucose and LA from α-cellulose. Ultrasonic pretreatment could decrease the degree of crystallinity and polymerization of α-cellulose, enhance the accessibility of acid sites and ZnCl2 to the loosened amorphous regions of α-cellulose in water, and improve the hydrolysis efficiency of α-cellulose. The desilicated ZSM-5 (HZSM-5-DS(0.2)) showed much higher catalytic activities as compared to commercial ZSM-5 and α-cellulose conversion reached 76.5% over HZSM-5-DS(0.2) at 200 °C. Catalytic conversion of α-cellulose consisted of at least three important parallel reactions under the present hydrothermal conditions and a plausible pathway was proposed. Effective control of these reactions would be helpful to further maximize the target product yield during the catalytic conversion of α-cellulose.

Lignin is the most abundant and renewable resources for production of natural aromatics. In this paper, new bimetallic catalytic system of Ru and Ni supported onto nitrogen-doped activated carbon (Ru-Ni-AC/N) was developed and its performances on hydrogenolysis of lignin model compounds under mild reaction conditions (1.0 MPa, 230 °C, in aqueous) were investigated. The results indicate that Ru-Ni-AC/N was a highly active, selective and stable catalyst for the conversion of lignin model compounds into aromatics, e.g. phenol, benzene and their derivatives. As verified by BET, XRD, HRTEM, XPS, H2-TPR and ICP-MS, the strong synergistic effects between i) Ru and Ni and ii) metals and N-groups were contributed to its excellent aromatics selectivity. What’s more, the introduction of electron rich N atoms on AC was beneficial to the stabilization of metal particles, which greatly enhanced the durability of the catalyst.

C-H methylation is an attractive chemical transformation for C-C bonds construction in organic chemistry, yet eff icient methylation of readily available (bio-)alcohols in water using methanol as sustainable C1 feedstock is limited. Herein, yolk-shellstructured mesoporous carbon nanospheres encapsulated Ir nanocatalysts (Ir@YSMCNs) have been synthesized for this transformation. Monodispersed Ir clusters (ca. 1.0 nm) w ere in situ encapsulated and spatially isolated within YSMCNs by a silicaassisted sol-gel emulsion strategy. A selection of (bio-)alcohols (19 examples) was selectively methylated in aqueous phase with goodto- high yields over the developed Ir@YSMCNs. The improved catalytic eff iciencies in terms of activity, selectivity together w ith the good stability and recyclability were contributable to the ultrasmall Ir clusters with oxidation chemical state as a consequence of the conf inement ef fect of YSMCNs w ith interconnected nanostructures.

In this study, different nanocellulose (NC) products were manufactured from corncob residue (CCR) through sulfuric acid hydrolysis, formic acid hydrolysis, and TEMPO-mediated oxidation methods (the products were referred as SCN, FCN, and TCN, respectively). The properties of NC products and their impact on rheological behavior of paper coatings were comparatively studied. Results showed that compared to SCN and TCN, FCN exhibited large dimensions, limited negative surface charge, and poor stability in their aqueous suspensions, while the FCN aqueous suspension displayed the highest viscoelastic modulus due to the formation of highly entangled network. In paper coatings, SCN exhibited superior thickening and promoted rheological function due to their highly charged surface and strong interactions with pigments and immobilized water molecules, in comparison with other NC products. This study verified that the NC derived from CCR could be utilized as green and renewable additives to improve rheological prope...

In this paper, variables of Pulp Refining Instrument (PFI) refining assisted alkaline pretreatment and hydrolysis saccharification of corn stover were analyzed. The process parameters were characterized by multivariate data analysis methods including Principle Component Analysis and Partial Least Square (PCA and PLS) to investigate the specific relationships of primary variables in alkali-based pretreatment of biomass. In this paper, pretreatment system was multivariate and the variables were inter-related to each other. Total alkaline charge and removal rate of lignin had greatest impact on the pretreatment and enzymatic hydrolysis.

In this article, a simple strategy was employed to fabricate bioinspired hybrid composite with carboxymethyl cellulose (CMC), graphene oxide, and reduced graphene oxide/alumina (rGO/Al) by a facile solution casting method. The tensile strength and toughness of rGO/Al-CMC-GO can reach 586.6 ± 12 MPa, 12.1 ± 0.44 MJm–3, respectively, due to the interface strengthening of alumina, which is 1.43 and 12 times higher than steel and about 4.3 and 6.7 times that of nature nacre. The artificial nacre hybrid composite is conductive due to the introduction of rGO/Al on the surface. Interestingly this structure can also be coated on the surface of cotton thread to give the thread good mechanical performance and conductivity. Additionally, the artificial nacre has better fire shielding and gas barrier properties. The oxygen permeability (OP) for 1% rGO/Al-CMC decreased from 0.0265 to 0.003 mLμm m–2 day–1 kpa–1, the water vapor permeability (WVP) decreased from 0.363 to 0.205 gmmm–2 day–1 kpa–1 when the concentration i...

In this work, novel nanoflower/alginate microbeads were synthesized to immobilize α-acetolactate decarboxylase (ALDC) with a facile approach. Typically, ALDC was first coprecipitated with Ca3(PO4)2 to form enzyme-inorganic hybrid nanoflowers (Ca3(PO4)2-ALDC), and then the nanoflowers containing micrometre-sized particles and nanoscale flower-like petals were entrapped in alginate gel beads (Ca3(PO4)2-ALDC) @Alg). Compared with free ALDC and Ca3(PO4)2-ALDC nanoflowers, the microbeads performed greatly improved recyclability and stability, meanwhile, retained 98% of activity compared with free ALDC. Moreover, the immobilized enzyme can be used in a 300 L beer fermentation tank to prevent the formation of diacetyl, solve the problem of beer off-flavor and short the beer maturation time, thus exhibiting a great potential application in beer brewing industry.

In this work, a lignin-based concrete water reducer was prepared through organic solvent fractionation and chemical modification of lignin extracted from pine wood with formic acid. The fractionated lignin with different molecular weight was modified via oxidation–sulfomethylation (OS), and the effects of fractionation on the performance of lignin-based concrete water reducer were investigated. It was found that the sulfonation degree (SD) of the fractionated lignin after OS was clearly higher compared to the unfractionated lignin, and the SD of fractionated lignin was linearly correlated with its workability (i.e., the fluidity of cement paste) based on the results obtained. By adding the same quantity of modified lignin-based concrete water reducer, the fluidity of cement paste with the fractionated lignin (by pure acetone) after OS modification was 21% higher than the sulfonated FAL (M-FAL) without fractionation. The organic solvents used in this study could be easily recovered and reused. Thus, the wh...

Different functional groups (i.e. NH2, COOH, OH and nitrogen-doping) modified CNTs (denoted as AMCN, CMCN, HMCN and NMCN, respectively) supported ruthenium catalysts (Ru/AMCN, Ru/CMCN, Ru/HMCN and Ru/NMCN) were prepared by incipient wetness impregnation method. They were fully characterized by XRD, TG, Raman, XPS, TPD and TEM to elucidate the relationship between the physical property and their catalytic performance. TEM results shown that Ru particles were well dispersed on the surface for all the samples with the size of 1.48–1.99 nm. The effects of functional groups of carbon nanotubes (CNTs), nitrogen doping and base additive types on activity and selectivity of ethylene glycol (EG) and propylene glycol (1,2-PD) were investigated. In addition, the activity and final products distribution were much influenced by the properties of functional groups on CNTs and the type of metal cation of the base promoters, which probably participated in the reaction for accelerating a retro-aldol reaction for C C cleavage. Among the catalysts, Ru supported on AMCN exhibited the best catalytic activities and glycols selectivities than on MCN, CMCN, HMCN and NMCN.

The search for and exploitation of efficient catalytic systems for selective conversion of furfural into various high value-added chemicals remains a huge challenge for green synthesis in the chemical industry. Here, novel Pt nanoparticles supported on bamboo shoot-derived porous heteroatom doped carbon materials were designed as highly active catalysts for controlled hydrogenation of furfural in aqueous media. The porous heteroatom doped carbon supported Pt catalysts were endowed with a large surface area with a hierarchical porous structure, a high content of nitrogen and oxygen functionalities, a high dispersion of the Pt nanoparticles, good water dispersibility and reaction stability. Benefiting from these features, the novel Pt catalysts displayed a high activity and controlled tunable selectivity for furfural hydrogenation to produce furfuryl alcohol and cyclopentanone in water. The product selectivity could be easily modulated by controlling the carbonization temperature of the porous heteroatom doped carbon support and the reaction conditions (temperature and H2 pressure). Under mild conditions (100 °C, 1 MPa H2), furfuryl alcohol was obtained in water with complete conversion of the furfural and an impressive furfuryl alcohol selectivity of >99% in the presence of Pt/NC-BS-500. A higher reaction temperature, in water, favored rearrangement of the furfural (FFA) with Pt/NC-BS-800 as the catalyst, which resulted in a high cyclopentanone yield of >76% at 150 °C and 3 MPa H2. The surface properties and pore structure of the heteroatom doped carbon support, adjusted using the carbonization temperature, might determine the interactions between the Pt nanoparticles, carbon support and catalytic reactants in water, which in turn could have led to a good selectivity control. The effect of different reaction temperatures and reaction times on the product selectivity was also explored. Combined with exploration of the distribution of the reaction products, a reaction mechanism for furfural reduction has been proposed.

A composite HZSM-5@cubic ordered mesoporous SiO2 (HZ@COMS) was synthesized by an acidic sol–gel coating method with template Pluronic F127. HZ@COMS and Ga loading HZ@COMS (Ga/HZ@COMS) were applied in methanol to aromatics (MTA). The existence of the silica shell reduces the acid amount and acidity of HZSM-5, which decreases in the formation of coke on the catalyst. At the same time, such silica shell with 3D hierarchical and cubic ordered mesopores improves the diffusion of seeds and coke precursor. As a result, the catalytic performance of HZSM-5 was improved effectively with the introduction of silica shell in such structure. Making a comparison with HZSM-5, the longevity of HZ@COMS increased from 10 to 42 h and the selectivity of BTX increased from 44 to 49%. After Ga’s loading, the cubic ordered mesopore offered a nanoscale reactor in the reformation of C9+ hydrocarbons, which further improves the longevity of catalyst (54 h) and the selectivity of BTX (50%). Ga/HZ@COMS presents good ability in the regeneration ability in MTA.

In this work, nanocellulose was extracted from bleached corncob residue (CCR), an underutilized lignocellulose waste from furfural industry, using four different methods (i.e. sulfuric acid hydrolysis, formic acid (FA) hydrolysis, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, and pulp refining, respectively). The self-assembled structure, morphology, dimension, crystallinity, chemical structure and thermal stability of prepared nanocellulose were investigated. FA hydrolysis produced longer cellulose nanocrystals (CNCs) than the one obtained by sulfuric acid hydrolysis, and resulted in high crystallinity and thermal stability due to its preferential degradation of amorphous cellulose and lignin. The cellulose nanofibrils (CNFs) with fine and individualized structure could be isolated by TEMPO-mediated oxidation. In comparison with other nanocellulose products, the intensive pulp refining led to the CNFs with the longest length and the thickest diameter. This comparative study can help to provide an insight into the utilization of CCR as a potential source for nanocellulose production.

Allylic alcohols are the essential building blocks widely used in diverse streams of organic inventions for pharmaceuticals, fragrances, agrochemicals and polymers. Currently, allylic alcohols are industrially produced from petroleum-based feedstocks via atom uneconomic processes. More sustainable synthesis route for allylic alcohols is limited. Herein, a methodology for the direct and highly selective production of allylic alcohols has been accomplished by controlled dehydrogenative α-methylenation of alcohols with methanol. This transformation is enabled by interfacial Lewis acid-basic pair on tailor-made ZnO/4Mg1ZrOx mixed oxide. High selectivity (83∼92%) of allylic alcohols is the consequence of alcohols acceptorless dehydrogenation to liberation of H2 and Meerwein-Ponndorf-Verley type hydrogen transfer onto C = O bonds of unsaturated aldehydes. Furthermore, the prepared ZnO/4Mg1ZrOx mixed oxide shows good stability after 200 h time on stream test. These observations could additionally allow us to design multifunctional solid acid-basic catalysts for the transformations of renewable oxygenates into value-added chemicals.

Tetrahydrofurfuryl alcohol (THFA) has been identified as a platform chemical of interest because of its production from biomass. It can be converted into valuable alcohols and ethers by selective hydrogenation/hydrogenolysis reaction over Rh-based metal catalysts. To better understand the chemistry of THFA, the reaction energies and the corresponding energy barriers of selective C–O bond hydrogenolysis and ring-opening of THFA on Rh(111) for the formation of 2-methyltetrahydrofuran (2-MeTHF), 1,5-pentanediol (1,5-PeD), and 1,2-pentanediol (1,2-PeD) were studied using density functional theory (DFT) calculations. The results indicate that starting from THFA to produce 2-MeTHF, the direct C–O bond cleavage of the CH2OH group is not favored. Alternatively and more preferentially, the reaction occurs through the initial activation of C–H bond on the side chain, followed by dehydroxylation and hydrogenation. On the other hand, in the metal catalyzed ring-opening process of THFA to 1,5-PeD and 1,2-PeD, the firs...

Lignocelluloses have been the focus of much attention, because of their conversion to fermentable sugars for cellulosic ethanol production, both from the viewpoint of energy and the environment. Pretreatment plays a crucial rule in biomass conversion, to overcome the chemical and structural difficulties, which have evolved in lignocelluloses, and to produce a cost-effective fermentable sugar via enzymatic saccharification. Among the developed pretreatment approaches, alkali-based pretreatment technology, which can utilize the equipment and chemical recovery system in the pulping industry, has been considered one of the most promising pretreatment methods, mainly because of its high efficiency in delignification and high final total sugar yields. This paper reviews the classification, mechanism, advantages, disadvantages, and the progress of alkali-based pretreatment technologies, in order to better understand the fundamental principles of alkali-based pretreatments. This is of vital importance for the pro...

A method was presented for fabricating the fluorescent nanocomposites containing CdTe quantum dots (QDs) and montmorillonite (MMT)-chitosan (CS). MMT-CS/CdTe QDs nanocomposites were prepared via a simple, versatile and robust approach combination of covalent and electrostatic assembly methods (Scheme 1). The negatively charged MMT was initially modified with positively charged CS through electrostatic assembly, followed by incorporation of CdTe-QDs into the MMT-CS nanosheets by covalent connections between the amino groups of CS and the carboxylic acid groups of thioglycollic acid (TGA). The X-ray diffraction (XRD), High resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) and the FTIR were used to prove the QDs have intercalated into the MMT-CS matrix. The fluorescence emission spectra showed that the MMT-CS/CdTe QDs nanocomposites had the best fluorescence intensity compared with the bare CdTe QDs and CS-QDs.

Cellulose nanocrystals (CNCs) can be used as building blocks for the production of many renewable and sustainable nanomaterials. In this work, CNCs were produced from bleached eucalyptus kraft pulp with a high yield over 75 % via FeCl3-catalyzed formic acid (FA) hydrolysis process. It was found that the particle size of resultant CNC products (F-CNC) decreased with the increase of FeCl3 dosage in FA hydrolysis, and a maximum crystallinity index of about 75 % could be achieved when the dose of FeCl3 was 0.015 M (i.e. about 7 % based on the weight of starting material). Thermogravimetric analyses revealed that F-CNC exhibited a much higher thermal stability (the decomposition temperature was over 260 °C) than S-CNC prepared by typical sulfuric acid hydrolysis. In the FeCl3-catalyzed FA hydrolysis process, FA could be easily recovered and reused, and FeCl3 could be transferred to Fe(OH)3 as a high value-added product. Thus, the FeCl3-catalyzed FA hydrolysis process could be sustainable and economically feasible. In addition, F-CNC could be well dispersed in DMSO and its dispersibility in water could be improved by a cationic surface modification.

Sustainable production of liquid transportation fuels and chemicals remains essential both commercially and scientifically. Isobutanol has gained great attention as an improved “drop-in” biofuel and important commodity chemical with broad applications. Ethanol could be upgraded with methanol in water for the production of isobutanol through cross condensation. High isobutanol selectivity is obtained (>90%) due to precise control on the reactivity of methanol and ethanol feedstock over Ir catalysts immobilized on N functionalized carbon materials. Only under a narrow range of preparation conditions could the catalysts distinguish the reactivity of methanol and ethanol nicely. The experimental results evidenced that the properties of Ir, especially the particle size and oxidation state, were particularly important for the desired activity. Control experiments also indicated that the effect of Ir catalysts on the intermediate aldol C–C formation step, rather than the dehydrogenation step, was critical in determining the product selectivity. Furthermore, the Ir catalysts could tolerate some typical biogenic impurities, which enables catalytic upgrading of bio-ethanol broth after centrifugation and decolourization. All these results indicate the promising application of the developed Ir catalysts in producing biofuels as well as useful chemicals from ethanol upgrading.

Cellulosic materials are becoming more and more important in our daily life. However, if cellulose in its natural form such as paper is to be applied in advanced applications, it should exhibit unique characters in mechanical performance, barrier properties, etc. This paper describes a new method to design and fabricate a pure cellulosic composite with excellent mechanical and barrier properties via simple coating and cross-linking between original paper and regenerated cellulose. The cellulosic composite overcomes the shortcomings of the low mechanical and barrier performance of original paper. This material had an ultrahigh tensile strength, a high elongation and toughness at break of 76 MPa, 12% and 7 MJ m−1, and 13 MPa, 11% and 0.75 MJ m−3 under wet conditions, which were greater than those of original paper (dry: 20 MPa, 2.8%, 0.3 MJ m−3; wet: 1.08 MPa, 2.8%, 0.028 MJ m−3). Besides, the composite papers showed good barrier properties for small molecules such as polar molecules (H2O) and non-polar molecules (O2). Interestingly, the as-synthesized material exhibited shape-retention when the material was wetted with water.

The direct reductive amination of carbonyl compounds with NH3 and H2 is an alternative route to produce primary amines in practical production. The search for efficient and selective catalysts has attracted great interest. In the present work, the reductive amination of heptaldehyde with NH3 was investigated over a Ru-based catalyst. The product selectivities were found to be related with the supports of Ru. The alumina with spinel structure (γ-Al2O3, θ-Al2O3)-supported Ru catalysts exhibited selectivity favoring primary amines (94% yield) at 100% heptaldehyde conversion under optimal conditions. Purely basic (MgO, CaO) and relative acidic (Nb2O5, SnO2, MCM-41, HZSM-5) supports showed relatively poor selectivity towards primary amines (0%–53% yield). The reductive amination mechanism was also proposed. The Schiff base N-[heptylene]heptyl-1-amine was a key intermediate. Ru/γ-Al2O3 was shown to be an excellent hydrogenolysis catalyst to selectively produce primary amine by amination and hydrogenolysis of N-[heptylene]heptyl-1-amine.

A modified alkali pretreatment (MAP) process was established in both lab-scale and pilot-scale, based on the on-line production and utilization of lignosulfonate for improving enzymatic saccharification of corn stover. Sodium lignosulfonate (SLS) produced by directly sulfonating lignin in spent liquor separated from alkali pretreatment was reused in the next cycle of alkali pretreatment. The results showed that, by using 11 wt% NaOH, 2 wt% SLS and 0.1 wt% anthraquinone (AQ) in MAP, delignification rate and final total sugar yields could reach about 78% and 80% respectively, which were about 6% and 9% higher compared to the blank conventional NaOH pretreatment under the same conditions. In addition, sulfonation degree of SLS had linearly impact on the final total sugar yields. (C) 2015 Elsevier B.V. All rights reserved.

In this work, the effectiveness of hydrogen peroxide-assisted sodium carbonate (HSC) pretreatment of corn stover to produce fermentable sugars was investigated. It was found that the addition of H2O2 (a green oxidative agent) in Na2CO3 pretreatment could enhance the lignin removal and increase the hydrophilicity of the residual lignin, leading to the improved enzymatic digestibility and the yield of fermentable sugars. Also, results showed that lignin removal (in the range of 12-65%) was positively and linearly correlated with final total sugar yields. Post PFI refining could further improve the enzyme accessibility by increasing porosity of substrates. After HSC pretreatment (40 wt % Na2CO3 and 15 wt % H2O2 120 degrees C for 60 min) and enzymatic hydrolysis, the final total sugar yield could achieve 79%, which was about 10% higher in comparison with the conventional Na2CO3 pretreatment under the same conditions. HSC pretreatment will have less environmental impact and less barriers for large scale production.

The activities and selectivities of MgO-supported Ni, Cu, and Co catalysts have been compared in aqueous-phase hydrogenolysis of sorbitol to glycerol and glycols. All catalysts effectively catalyzed the sorbitol conversion into C2 and C3 polyols like glycerol, 1,2-propylene glycol, and ethylene glycol, but with different product distributions. The differences in activities and selectivities are ascribed to their different dehydrogenation/hydrogenation activities. The influences of base promoter, temperature, H-2 pressure, and reaction time were also studied. Added base promoter and prolonged reaction time enhanced sorbitol conversion for the three catalysts, but led to product degradation and decreased selectivity over Ni-MgO and Co-MgO, whereas selectivity maintained almost unchanged over Cu-MgO. (C) 2015, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Composite aerogels with excellent mechanical properties were prepared by using carboxymethyl cellulose (CMC) as raw materials, 2D graphene oxide (GO) nanosheets as reinforcement, boric acid (BA) as cross-linker. By controlling the heat transfer rate, composite aerogels with isotropy and anisotropy structure were prepared, the mechanical and heat insulation properties were studied. The isotropy composite aerogel had compression strength of 110 kPa at 60% compression, which was 5 times of the axial and 14 times of the radial of anisotropy structure composite aerogels, and thermal conductivity was also lower than those of two directions of anisotropy composite aerogel. Besides, the mechanical properties of isotropy composite aerogels increased with the increase of GO content. When GO content was up to 5 wt%, the compressive strength and Young’s modulus of composite aerogels reached 349 kPa and 1029 kPa, which were 1.6 and 4.5 times that of CMC aerogels, respectively.

At present, China's petrochemical industry is facing significant challenges of resources and environment. In the future, the bulk chemical manufacture is moving towards high resources utilization efficiency, usage of multiple raw materials, design of high value-added product, green and low-carbon processes. In the present situation, the develop-ment of novel industry by integrated chemo-and bio-transformation, i.e., combining the green, specifity characteristics in biotechnology with the high-efficiency, scaled separation and catalysis in current chemistry industry in one process, is very important in promoting the sustainable development in bioenergy and modern petrochemical industry. This article gives some examples of innovation practices on combined chemo-and bio-transformation systems from non-fossil fuel raw materials, including combined raw materials, processes and products. Finally, outlook and suggestions are given on enhancing technological development for sustainable combined chemo-and bio-transformation for bulk chemicals.

The effect of active carbon pretreatment on the catalytic performance of Pd/C catalysts in the hydrogenation of itaconic acid was studied. The catalysts were prepared by deposition-precipitation and characterized by XRD, BET, NH3-TPD, TEM and FT-IR. Due to the modification of the surface functional groups, surface structure and surface acidities of active carbon via pretreatment, the Pd/C catalysts showed varied catalytic performances. High dispersion and uniform particles were conducive to the excellent activity of Pd/C catalyst with support copretreated with HNO3 and NaClO, which exhibited 89.5% selectivity towards methyl-gamma-butyrolactone at 180 degrees C, 4 MPa H-2 for 20 h. (C) 2014 Elsevier B.V. All rights reserved.

In this work, novel hybrid microbeads composed of chemically reduced graphene oxide (CRGO) and alginate were fabricated, which could encapsulate enzymes by a simple non-covalent adsorption-entrapment method. Compared with alginate gel beads, the intervention of CRGO in the alginate gel enhanced its mechanical strength, effectively prevented the leakage of enzyme, and greatly enhanced the stability and environmental tolerance. Compared with free enzymes or those on a single carrier, the enzyme encapsulated in these hybrid microbeads can retain its optimum activity within a broad range (temperature 45-60 degrees C, pH 4-6). Additionally, the microbeads can be easily recycled by simple filtration and filled into a column to achieve a continuous fixed-bed enzyme catalytic reaction.

The acidic zeolite HZSM-5 (Si/Al = 25) achieved 58.9% selectivity of methyl furfuryl ether (MFE) and 44.8% selectivity of ethyl furfuryl ether (EFE) from etherification of furfuryl alcohol with methanol and ethanol. MFE and EFE were quantitatively hydrogenated into methyl tetrahydrofurfuryl ether (MTE) and ethyl tetrahydrofurfuryl ether (ETE) using a Raney Ni catalyst.

Succinic acid is an important biomass-derived C4 building block and is ready to be converted into various value-added chemicals. Here we report that tunable selectivity for the formation of 1,4-butanediol, gamma-butyrolactone and tetrahydrofuran from aqueous succinic acid hydrogenation could be achieved on FeOx-promoted Pd/C catalysts. Fe was found to be an efficient promoter for the succinic acid hydrogenation, which not only improved the activity of the catalysts but also tuned the product distribution. Succinic acid could be transformed into 1,4-butanediol with a yield of over 70% in the presence of the Pd5FeO(x)/C catalyst under the relatively mild conditions of 200 degrees C and 5 MPa H-2. The reaction pathway was also proposed according to the reaction and characterization results.

In this work, modification of graphitic carbon nitride photocatalyst with acid was accomplished with a facile method through reflux in different acidic substances. The g-C3N4-based material was found to be a metal-free photocatalyst useful for the selective oxidation of benzyl alcohol with dioxygen as the oxidant under visible light irradiation. Acid modification had a significant influence on the photocatalytic performance of g-C3N4. Among all acid tested, sulfuric acid-modified g-C3N4 showed the highest catalytic activity and gave benzaldehyde in 23% yield for 4 h under visible light irradiation, which was about 2.5 times higher than that of g-C3N4. The acid modification effectively improved surface area, reduced structural size, enlarged band gap, enhanced surface chemical state, and facilitated photoinduced charge separation, contributing to the enhanced photocatalytic activity. It is hoped that our work can open promising prospects for the utilization of metal free g-C3N4-based semiconductor as visible-light photocatalyst for selective organic transformation. (C) 2014 Elsevier Ltd. All rights reserved.

Selective hydrogenolysis of biomass-derived tetrahydrofurfuryl alcohol (THFA) to produce 1,5-pentanediol (1,5-PeD) is accomplished by a binary catalyst consisting of MoO3 and supported Rh nanoparticles; a 1,5-PeD selectivity up to 80% is achieved in the present work. Moreover, a very interesting phase-transfer behavior for MoO3 during the reaction is observed with the assistance of different characterization techniques. In this process, MoO3 dissolves partially in the liquid phase under the reaction conditions and is transformed into the soluble hydrogen molybdenum oxide bronzes (HxMoO3) in the presence of H2, which are recognized as the genuinely active sites for the C–O bond breaking of THFA. Density functional theory (DFT) calculations were then carried out to simulate the plausible mechanisms and highlight the role of Mo in the ring-opening process of THFA in more detail. We propose that the formation of 1,5-PeD takes place in a two consecutive reactions. THFA first undergoes acid-catalyzed ring-openi...

In this work, corn stover was refined by a pulp refining instrument (PFI refiner) after NaOH pretreatment under varied conditions. The quantitative characterization of the influence of PFI refining on enzymatic hydrolysis was studied, and it was proved that the enhancement of enzymatic saccharification by PFI refining of the pretreated corn stover was largely due to the significant increment of porosity of substrates and the reduction of cellulose crystallinity. Furthermore, a linear relationship between beating degree and final total sugar yields was found, and a simple way to predict the final total sugar yields by easily testing the beating degree of PFI refined corn stover was established. Therefore, this paper provided the possibility and feasibility for easily monitoring the fermentable sugar production by the simple test of beating degree, and this will be of significant importance for the monitoring and controlling of industrial production in the future.

Vapor-phase catalytic dehydration of 1,2-propanediol was investigated over Zirconia-supported niobia catalysts. The catalysts exhibit selectivity favoring propanol (approximately 39%) at 85.0% 1,2-propanediol conversion at 290 degrees C under 1 atm N-2. The ZrNbO catalysts were analyzed by various techniques; the results indicated that the active sites were weak Bronsted acid sites. A dehydration and hydrogen transfer mechanism was also proposed. (C) 2013 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Porous N-doped carbons hold good prospects for application in supercapacitor due to their low-cost, large surface area, good surface wettability, high electrical conductivity as well as extra pseudocapacitance. However, most synthetic methods required the tedious and multiple-step process with the assistance of hard/soft templates or the massive use of chemical reagents, and exogenous nitrogen sources, which made them difficult to realize industrial production and application. Here, we described a novel hierarchical porous N-doped carbons fabricated by a facile and sustainable approach via hydrothermal treatment and subsequent carbonization process by using renewable bamboo shoots as the starting material without any templates, additional chemical activation and nitrogen source. The obtained bamboo shoot-derived carbons possessed a large BET surface area (up to 972 m2 g−1), hierarchically interconnected porous framework, rich and uniform nitrogen incorporation (3.0 at%). Benefiting from these unique features, the novel carbon-based electrode materials displayed a high capacitance of 412 F g−1 in KOH electrolyte and long cycling life stability. Thus, an advanced electrode material for high-performance supercapacitor was successfully assembled by a simple and scalable synthesis route with abundant renewable resources freely available in nature.