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With the deepening of aging, pension institutions have gradually become the focus of research, and the reasonable distributions and locations of pension institutions have great impact on their own functions. Taking Henan Province as the study area, the spatial distribution characteristics of pension institutions are analyzed by the nearest neighbor index method and the kernel density estimation method, the accessibility of pension institutions with a single service radius and its influencing factors are analyzed by improved potential model and two-step floating catchment area method. The results are that: (1) the pension institutions in Henan Province generally show the characteristics of “central cohesion-denseness in the north and sparseness in the south”, and have the trend of development in marginal areas. (2) The spatial accessibility of pension institutions decreases from northeast to southwest, positively affected by economy, public service, per capita income of residents and negatively impacted by the elderly population. (3) The improved potential model is more suitable to evaluate the spatial accessibility of pension institutions in Henan Province.

Developing the active and environmentally friendly non-noble nano-catalysts is highly desired to transform biomass-derived platform into value chemicals. Herein, we report a low-cost and sustainable cobalt/nitrogen-doped carbon catalyst containing both metallic Co and Co-N components exhibits satisfying activity for the oxidative esterification of 5-hydroxymethylfurfural and other investigated alcohols in methanol without the base additive under mild conditions. Experimental results show that an appropriate ratio of Co to Co-N is responsible for the high activity of the Co/Co-N/CN catalysts towards oxidative esterification. Theoretical computational results demonstrate that the Co/Co-N group synergistically promotes electron transfer from the Co adatom to the surface oxygen atoms, facilitates O2 adsorption and activation on the Co sites, and further reduces the energy barrier for the oxidation of alcohols to aldehydes, all of which contribute to the overall activity of oxidative esterification of alcohols to the corresponding esters. In addition to exhibiting superior intrinsic activity, the as-prepared Co/Co-N/CN catalyst also shows excellent stability and recyclability.

Algal biomass was converted into 5-aminolevulinic acid (5-ALA) in five chemical steps: conversion to 5-(chloromethyl)furfural (5-CMF), ammoniation, ring-opening (photo-oxidation), reduction, and hydrolyzation. Among them, we mainly focused on the 5-CMF production and the following ammoniation. To our knowledge, the mixed solvent catalytic system of deep eutectic solvent (DES) and low concentration hydrochloric acid is the first reported for the synthesis of 5-CMF from algal biomass, providing a 24.6% 5-CMF yield at 120 °C for 5 h. Potassium phthalimide (KPI) was employed as an ammoniation reagent with superb selectivity and activity instead of conventional sodium azide (NaN3). Optimizing the experimental design, a 23.7% 5-ALA yield along with high purity (>96%) was achieved from 5-CMF, and the total 5-ALA yield was 5.8% from algal biomass. This work provides a green and mild pathway for 5-ALA production from algal biomass.

Higher alcohol synthesis (HAS) from biomass-derived syngas (CO/H2) is of considerable interest but has a challenge to achieve a satisfying yield, as it is a competitive reaction between C–C couplin...

Recently, we reported a synthetic approach to obtain renewable phthalic anhydride (PA) from 5-hydroxymethfurfural (HMF) with a yield of 63.2% using MoO3/Cu(NO3)2 as a catalyst in one pot, for the first time. The reaction pathway has been elucidated in our previous study. Herein, the synergistic catalytic mechanism of MoO3/Cu(NO3)2 for the oxidation of HMF to PA was investigated. The commercially available MoO3 (c-MoO3) with superior characteristics, including more lattice oxygen and better oxygen-donating capacity, provides higher activity for the oxidation of HMF to PA. More importantly, the synergy between c-MoO3 and Cu(NO3)2 ensured the high yield of PA through the Mo6+/Mo4+ redox couple facilitated by the redox cycling of Cu2+/Cu+ with the assistance of oxygen.

Manganese catalyzed transfer hydrogenation (CTH) of aldehydes is an attractive method for the synthesis of alcohols. Here, we report a novel and efficient MnO@C-N catalyst for the CTH of biomass-derived 5-hydroxymethylfurfural and other aldehydes to alcohols in high yields. Catalytic experimental studies showed that the MnO and nitrogen-doping are responsible for the high selectivity and high conversion, respectively. Isotopic labelling experiments demonstrated that the CTH of aldehydes to alcohols over MnO@C-N is via a route by direct hydrogen transfer. Kinetic studies revealed that the N-doping can improve the reaction rate and reduce the activation energy of the aldehydes conversion. DFT calculations also indicated that both pyridine N and pyrrolic N doping can reduce the energy barrier for acetone desorption by the interaction between N and hydroxyl-H of alcohol. Furthermore, MnO@C-N showed good recyclability for at least five reaction cycles. We anticipate that these results can drive progress in the manganese catalyzed transfer hydrogenation reaction.

Mussel-inspired hydrogels have gained attention for underwater applications, including treatment of wastewater. However, they are typically limited by poor mechanical properties, short-term mechanical stability and by not being reusable. Here, we develop a mechanically stable and self-healing hydrogel with high mechanical strength for the degradation of dyes in wastewater, based on cellulose-derived co-polydopamine@Pd nanoparticles. A dynamic catechol redox system was achieved by reversible conversion between semiquinone and quinone/hydroquinone radicals, endowing the hydrogel with stable mechanical properties and self-healing behavior. Furthermore, a graphene oxide membrane is covalently grafted on to the hydrogel surface, which regulates its water permeability and intercepts some metal ions or large particles, protecting the hydrogel structure. High catalytic activity for anionic and cationic dyes is achieved, with the degradation rate reaching more than 95% after multiple cycles without significant deterioration in performance or hydrogel structure. Our work demonstrates a route to achieve mechanically stable hydrogels for degradation of organic dyes in wastewater. Hydrogels are attractive for the treatment of waste water, but their mechanical properties are typically reduced when underwater. Here, a synthesis strategy is reported for a graphene oxide-coated hydrogel which can catalyze organic dye degradation in water over multiple cycles.

A novel approach to produce renewable maleic anhydride (MA) from bio-based platform chemical 5-[(formyloxy)methyl]furfural (FMF) was developed with air or pure oxygen at atmospheric pressure using ...

2,5-Bis(hydroxymethyl)furan (BHMF) as well as furfuryl alcohol (FFA) are considered as highly valuable biomass-derived alcohols resembling aromatic monomers in polymer synthesis. Herein, a series of cobaltic nitrogen-doped carbon (Co-NC) catalysts calcinated at different temperatures were synthesized and tested for the solvent-free hydrogenation of 5-hydroxymethylfurfural (HMF) to prepare BHMF. It was found that the Co-NC catalyst calcinated at 600 °C (Co-NC-600) exhibited a superior catalytic activity in the hydrogenation reaction mainly due to the doping of graphitic N, which probably facilitated the polarization of H

Large eddy simulation is used to study the gas-particle two-phase transverse jet in supersonic flow. In this paper, the Eulerian method is used to simulate the fluid, and the Lagrangian method is used to simulate the particles. The numerical study is carried out for different particle mass fractions and Stokes numbers with the jet-crossflow momentum flux ratio and the Mach number of crossflow being kept constant. It is found that the larger particles (St = 5) are mainly located above the counter-rotating vortex pair, and the smaller particles (St = 0.9) are mainly located in the counter-rotating vortex pair. Due to the Kelvin–Helmholtz instability, several characteristic phenomena have been observed, including particle trailing and the wave structure constructed of the particle cloud, and the particles also make the Mach disk lower.

Compressible and ultralight carbon aerogels are attractive due to its compressibility, elasticity and conductivity. However, it is still a great challenge to enrich the properties of carbon aerogel to meet various requirements. Herein, we report an untralight, supercompressible, fatigue resistant, superhydrophobic and fire-resistant and multifunctional CNF-GO/glucose-kaolin carbon aerogel (C-NGGK) carbon aerogel. To achieve such excellent performances, calcined GO, CNFs, glucose and kaolin are used for forming low-density and continuous wave-shape rGO layers, reinforcing the mechanical strength of carbon layers, realizing superelasticity and fatigue resistance and resulting in a superhydrophobic surface for C-NGGK, respectively. The as-prepared C-NGGK demonstrates excellent superhydrophobicity with the water contact angle (WCA) of 124.9°, and the absorption efficiency of the C-NGGK samples for different oils and organic solvents are 75–255 times their own weight. These advantages show that the C-NGGK can be an ideal candidate for oil/water separation. In addition, there is also the prospect to be used for pressure sensors, while other potential applications include three-dimensional electrode materials for supercapacitors and batteries, catalyst carriers and various wearable devices.

BACKGROUND: Biomass holds the promise to provide a sustainable future for the chemical industry. 2, 5‐Bishydroxymethylfuran (BHMF) is a versatile bio‐based diol with a broad range of potential applications in many polymeric materials, artificial fibers and drugs. However, the controlling of the BHMF selectivity in hydrogenation of biomass‐derived 5‐hydroxymethylfurfural (HMF) with complex transformation pathways is always a great challenge especially under solvent‐free conditions in which many side reactions may occur due to its rich reducible groups. RESULTS: A facile and effective approach was developed for the selective synthesis of BHMF by solvent‐free hydrogenation of a deep eutectic mixture consisting of HMF (75 wt%) and choline chloride (ChCl), by which a BHMF selectivity up to 94.6% was gained at full HMF conversion over Raney Co at 100 °C in 4 h. In addition, the HMF conversion and selectivity toward BHMF can be regulated and controlled through altering the strength of hydrogen‐bonding interactions of HMF‐based deep eutectic mixtures (ChCl–HMF mixtures). CONCLUSION: We developed an effective approach that allows the solvent‐free synthesis of BHMF via hydrogenation of HMF‐based deep eutectic mixtures. The extraordinary BHMF selectivity in the solvent‐free hydrogenation of HMF is reasonably attributed to the hydrogen‐bonding interactions formed between ChCl and HMF/BHMF which greatly suppresses the side reactions of HMF and the over‐reduction of BHMF. © 2020 Society of Chemical Industry

2, 5-Bishydroxymethylfuran (BHMF) has been currently emerged as a promising biomass-derived monomer. It is highly desirable to proceed a chemical process at a high substrate concentration, by which a facile and cost-effective separation of products can be expected. Herein, we report for the first time on the hydrogenation of highly concentrated 5-hydroxymethylfurfural (HMF) in deep eutectic solvents (DESs), giving a near quantitative selectivity towards BHMF in ChCl-glycerol DES at 25 °C in 3 h using NaBH4 as the H-donor. DES is hailed as a new class of green solvent, in which HMF/BHMF could be stabilized by the strong hydrogen-bond interaction, and allowed the selective hydrogenation of HMF at high concentration up to 40 wt%. Notably, the resulting BHMF could be facilely separated by extraction with ethyl acetate, and then high purity of BHMF with a desirable isolated yield around 80% was obtained after removing of ethyl acetate. Additionally, the reaction efficiency of HMF hydrogenation in DESs was verified to be strongly associated with the viscosity of DESs and the pKa value of hydrogen-bonding donor.

We report here that L-rhamnose, a less popular renewable and commercially available carbohydrate, can be used as a potential raw material to generate 5-methylfurfural (MF). In particular, nearly 100% yield of MF was achieved over 7 consecutive cycles in NaCl solution containing AlCl3 within 30 min, thus providing an alternative and industrializable way for the production of the potential bio-platform compound MF.

Directly oxidative esterification of Biomass-derived 5-hydroxymethylfurfural (HMF) into dimethyl furan dicarboxylate (DMFDCA) is a promising route for the replacement of petroleum-derived commodity chemical terephthalic acid (TPA) extensively employed in polyester synthesis. Co-based N-doped carbon materials are one of the most promising applied catalysts for oxidative esterification reaction, however, the active sites and reaction pathway of these catalysts have not been clearly clarified, which is crucial to the practical application. Herein, we report that ZIF-67 (a zeolitic imidazolate framework (ZIF)-type cobalt-containing MOF) derived Co@C-N material is a highly effective catalyst for the selective conversion of HMF into DMFDCA in 95% yield. The high activity of the ZIF-67 derived nanocarbon composites Co@C-N can be attributed to the electron transfer between nitrogen-doped carbon shells and Co nanoparticles. The appropriate graphitic N and pyridinic N doping increases the electronic mobility and active sites. Density functional theory (DFT) simulations indicated that oxygen, HMF and methanol molecules are adsorbed and activated on C-N materials. Furthermore, no 2, 5-diformylfuran (DFF) was captured as an intermediate because the oxidative esterification of aldehyde preferentially occurred than the oxidation of hydroxyl group in HMF. We anticipate that these results can drive progress in the bio-based polymers sector and oxidative esterification reaction.

Herein, a synthetic pathway to renewable phthalic anhydride (PA) from 5-hydroxymethfurfural (HMF) in one pot is reported. The commonly available catalysts MoO3 and Cu(NO3 )2 play a crucial role in integrating the multiple steps of the reaction, namely decarbonylation of HMF to active furyl intermediate (AFI), oxidation of HMF to maleic anhydride (MA), Diels-Alder cycloaddition of AFI and MA, and subsequent dehydration, in one pot. Under mild reaction conditions, a 63.2 % yield of PA is obtained from HMF. Compared with the currently reported route to renewable PA based on the Diels-Alder cycloaddition of biomass-derived MA and furan, this convenient one-pot synthesis represents a great improvement in efficiency.

Controlling the structure, particularly the structure template stability, has great potential for the fabrication of high-capacity and renewable drug carriers. Herein, novel porous CaCO3 microspher...

A Direct connection experiment study of combustion mode transition was completed under the air conditions with Mach 2.2, total pressure 1.1 MPa and total temperature 1660 K, and a real-time identification method of combustion mode on dual-mode solid rocket scramjet was proposed. Based on the adiabatic assumption, the Mach number at the isolator exit could be calculated and used as the criterion for identifying the combustion mode. The pressure of the upper engine wall was measured during the test. It was found that the pressure of the isolator changes significantly during the combustion mode transition by analyzing the pressure changes in the isolator. The ratio of pressure between the exit and inlet P 𝑖/P 0 is below 2 when the combustion works in scram-mode, while the value of P 𝑖/P 0 is over 2 when it is in ram-mode.

While the synthesis of bio-based compounds containing carbon, oxygen and (to a lesser extent) nitrogen is well studied, the production of organosulfur compounds from biomass has received virtually no attention, despite their widespread application throughout the chemical industry. Herein, we demonstrate that a range of bio-based 2-thiothiophenes are available from the biopolymer cellulose, proving that functionally diverse small-molecule organosulfurs can be prepared independent of fossil carbon. This article is part of the theme issue ‘Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 2)’.

Transformation of biomass to chemicals and fuels is a long-term goal in both science and industry. However, high cost is one of the major obstacles to the industrialization of this sustainable technology. Thus, developing catalysts with high activity and low-cost is of great importance for biomass conversion. The last two decades have witnessed the increasing achievement of the use of earth-abundant 3d-transition-metals in catalysis due to their low-cost, high efficiency and excellent stability. Here, we aim to review the fast development and recent advances of 3d-metal-based catalysts including Cu, Fe, Co, Ni and Mn in lignocellulosic biomass conversion. Moreover, present research trends and invigorating perspectives on future development are given.