Electrodeposited 3D hierarchical NiFe microflowers assembled from nanosheets robust for the selective electrooxidation of furfuryl alcohol

A robust and green strategy for the selective upgrading of biomass-derived platform chemicals towards highly valuable products is important for the sustainable development.Herein,the efficient electrocatalytic oxidation of biomass-derived furfuryl alcohol(FFA)into furoic acid(FurAc)catalyzed by the electrodeposited non-precious NiFe microflowers was successfully reached under the low temperature and ambient pressure.The 3D hierarchical NiFe microflowers assembled from ultrathin nanosheets were controllably synthesized by the electrodeposition method and uniformly grown on carbon fiber paper(CFP).Electrochemical analysis confirmed that NiFe nanosheets more preferred in the selective oxidation of FFA(FFAOR)than oxygen evolution reaction(OER).The linear sweep voltammetry(LSV)in FFAOR displayed a clear decrease towards lower potential,resulting in 30 mV reduction of overpotential at 20 mA cm^(-2) compared with that of OER.The optimal catalyst Ni_(1)Fe_(2) nanosheets exhibited the highest selectivity of FurAc(94.0%)and 81.4%conversion of FFA within 3 h.Besides,the influence of various reaction parameters on FFAOR was then explored in details.After that,the reaction pathway was investigated and rationally proposed.The outstanding performance for FFAOR can be ascribed to the unique structure of 3D flower-like NiFe nanosheets and oxygen vacancies,resulting in large exposure of active sites,faster electron transfer and enhanced adsorption of reactants.Our findings highlight a facile and convenient mean with a promising green future,which is promising for processing of various biomass-derived platform chemicals into value-added products.

Modification of Wood by Tannin-Furfuryl Alcohol Resins-Effect on Dimensional Stability,Mechanical Properties and Decay Durability

Furfurylation is a well-known wood modification technology.This paper studied the effect of tannin addition on the wood furfurylation.Three kinds of dicarboxylic acids,adipic acid,succinic acid,and tartaric acid,as well as glyoxal as a comparing agent,were used to catalyse the polymerisation of furanic or tannin-furanic solutions during wood modification.Impregnation of furanic or tannin-furanic solution at a certain concentration into the wood followed with curing at 103℃for a specific duration was performed for the wood modification.Different properties of the modified woods like dimensional stability,resistance of treatment to leaching,mechanical properties,decay durability against white-rot(Coriolus versicolor,Pycnoporus sanguineus)and brown-rot(Coniophora puteana)as well as their chemical and anatomical characteristics were evaluated.Results revealed that the partial substitution of FA by the tannins improved the fixation of the chemicals impregnated in wood.Further,dimensional stability,leaching resistance,Brinell hardness,modulus of elasticity/modulus of rupture,and decay durability properties of the furfurylated wood were also improved in the presence of tannins.Scanning electron microscopy revealed the deposition of the polymer in the wood lumen cells and in the wood cell walls.

Emission of BTEX and PAHs from molding sands with furan cold setting resins containing different contents of free furfuryl alcohol during production of cast iron

At present, furan resin is the largest selling no-bake system of moulding sands. The most commonly used furan no-bake binders(FNB) are condensation products of furfuryl alcohol(FA) urea, formaldehyde and phenol. They are generally cured by exposure to organic sulfonic acids. FNB provide excellent mold and core strength, cure rapidly and allow the sand to be reclaimed at fairly high yields, generally 75%-80%, especially in applications where due allowance is made for the need to keep total sulfur content below 0.1%. However, due to probable carcinogenic properties of furfuryl alcohol, the EU Directive limits the content of this substance(in a monomer form in resin) to 25%. The classification of furfuryl alcohol and the resulting furan resin products has changed from "harmful" to "toxic by inhalation". The aim of this study was to determine the effect of free furfuryl alcohol content in the resin on the emission of harmful substances from the BTEX(Benzene Toluene Ethylbenzene & Xylene) and PAHs(polycyclic aromatic hydrocarbon) group exposed to high temperature and how it affects the emissions allowance of reclaimed sand in the matrix. Three resins from a leading manufacturer were examined, which contain a free furfuryl alcohol content of 71%-72%, about 50% and < 25%, respectively. The hardener for each resin was 65% aqueous solution of paratoluenesulfonic acid. Tests were carried out in semi-industrial conditions where liquid cast-iron was poured into sample sand mold at 1,350 °C. The matrix of the studied sands was reclaimed in the amount of 0, 50%, 100%, respectively.With the increase of free furfuryl alcohol content, the volume of evolved gases decreased. For all resins the main component from the BTEX group dominating in the emitted gases was benzene; however toluene also appeared in the amount of a few percentages. In contrast, ethylbenzene and xylenes occurred only in the gases emitted from resin-bonded sands with the largest furfuryl alcohol content. The increase in the share of reclaimed sands resulted in very significant increase in the volume of gas generated and participation of benzene in these gases. In terms of emission of compounds from the PAHs group virtually for all resins, the total content of these substances was comparable(within the limits of error). The main components were: fluoranthene, pyrene and benzo(a) anthracene.

Highly efficient catalytic valorization of biomass-derived hexoses and furfuryl alcohol in the presence of polymer-based catalysts

The catalytic transformation of furfuryl alcohol and hexose into value-added chemicals have been investigated with a series of polymer-based catalysts including poly(styrenesulfonic acid)(PSS),graphite oxide-doped poly(styrenesulfonic acid)(PSS-GO),and graphite-doped poly(-styrenesulfonic acid)(PSS-C).It is found that the selective conversion of furfuryl alcohol to methyl levulinate(MLE)was successfully performed with PSS as the catalyst,in which a 96.4%yield is attained in methanol solvent.Moreover,the efficient dehydration of D-fructose to produce 5-hydroxymethylfurfural(HMF)has also been achieved using PSS-GO as the catalyst,where a 76.5%yield of HMF was obtained in Nmethylpyrrodinone solvent.The effects of reaction temperature,time and solvent were investigated.Furthermore,the used catalysts have been respectively characterized by XRD,TG,FTIR,SEM and TEM techniques to reveal the physical properties and structures of these polymeric catalytic materials.

Effects of TiO_(2) Support and Cobalt Addition of Ni/TiO_(2) Catalyst in Selective Hydrogenation of Furfural to Furfuryl Alcohol

An effect of phase compositions(rutile,Rut and anatase,Ant)of TiO_(2)supports on the selective hydrogenation of furfural to furfuryl alcohol was investigated.The 15%wt Ni/TiO_(2)catalysts were prepared by incipient impregnation method.The result showed that Ni supported on anatase-rutile mixed phase TiO_(2)(91%Rut and 9%Ant,A2)provided the highest furfuryl alcohol yield at 43.8%due to the relatively strong Ni-TiO_(2)interaction,its appropriate crystallite sizes,and high average pore sizes.Furthermore,the effect of cobalt as a promoter on Ni/TiO_(2)-A2 catalysts was studied.The result showed that the Ni-Co/TiO_(2)-A2 catalysts exhibited poorer catalyst performances compared to the monometallic Ni/TiO_(2),probably because addition of cobalt can lower the reduction temperatures of Ni/TiO_(2)and weaken the metal-support interaction.

Preparation of an Abrasive Grinding Wheel Based on Tannin Resin Cross- Linked by Furfuryl Alcohol, Urea and Glyoxal

Simple bio-based abrasive grinding wheel based on thermosetting resin matrix was developed starting with condensed tannin and furfuryl alcohol,which are mainly derived from forest and agricultural products like tree barks,wheat and crops.Fourier transform infrared spectra(FTIR)signified the acidic conditions are quiet efficient for the reaction of furfuryl alcohol,urea and glyoxal all together and the-CH_(2)-NH-and-CH_(2)-O-CH(OH)-groups are predominating in cross-linking of the tannin-furfuryl alcohol-urea-glyoxal(TFUG)resin.The strengthening contribution of the tannin was also confirmed by the preservation of its distinct crystallinity using X-ray diffraction(XRD).Differential scanning calorimetry(DSC)and thermogravimetric analysis(TGA)ensured that TFUG resin can be cured at low temperature and offer higher heat resistance compared with phenol-formaldehyde(PF)resin.The high hardness and excellent compressive strength revealed by the corresponding investigations such as Brinell hardness,compression resistance,and grinding tests suggested a strong abrasive ability using the new grinding wheel compared with lab-made grinding wheel based on PF resin.This could be ascribed to the absence of cracks and low content of formed holes as confirmed using scanning electron microscopy(SEM)and balanced reaction conditions that leads to network structure with regular local reinforcements and homogeneous crosslink density.

DFT Study of Poly Furfuryl Alcohol-Rhodamine B Blend

A theoretical study of poly furfuryle alcohol (PFA), rhodamine B (Rh B) dye and their blends (PFA-Rh B) is carried out by using the density functional theory (DFT). Electronic states and opto-electronic properties are investigated. The electronic states indicate that the oligomers of FA are insulators and Rh B is a wide band gap semiconductor. Their blends have a narrow band gap of about 0.75 eV. The optoelectronic properties are studied using TDDFT, which indicates that the chain length of poly furfuryl alcohol is an effective parameter to control both energies and intensities of absorption in which longer chain causes absorption with high intensity within long wavelength. A single broad baned of electron excitations is more like 8-oligomer-RhB case, which centers at wavelengths about 599 nm and 625 nm. This band of absorption covers the whole visible region of spectrum.

Substitute materials of furfuryl alcohol in furan resin used for foundry and their technical properties

Based on a special synthesis process of furan resin,the furfuryl alcohol(FA),the main component of typical no-bake furan resins is substituted by ethanol and xylitol mother liquor which is relatively low price and chemically active.Through orthogonal test,the optimal amount of xylitol liquor,ethanol and modifier has been determined.Finally,the test results on technical properties show that the performance can meet the production requirement well,which indicate a success in this substituting attempt.

Predication of Selective Ring-opening Hydrogenolysis for Furfuryl Alcohol to Produce Pentanediol over Dual-atom Catalysts

Selective activation of C-O bond is of fundamental importance in the precise conversion of oxygenates into value-added compounds in an atom-economic and sustainable manner, and meanwhile, the structurally well-defined dual-atoms catalysts (DACs) have been scarcely investigated in this field. In this study, a series of transition metal DACs anchored on nitrogen-doped graphene (TM2/NC, TM=Pt, Ir, Rh, Pd, Ru, Co, Ni and Cu) was constructed to make a comprehensive investigation of their selectivity in the hydrogenative transformation of furfuryl alcohol (FAL), an important biomass platform molecule, to 1,2-pentanediol (1,2-PeD) via selective cleavage of furanic C5-O bond, by density functional theory (DFT) calculations and microkinetic modeling. We found that Ir2/NC demonstrated a high selectivity for the cleavage of furanic C5-O bond to produce 1,2-PeD, while the production of THFAL or 1,5-pentanediol (1,5-PeD) on other TM2/NC catalysts are more favorable. Furthermore, we found that the selective C-O bond cleavage of FAL furan ring is affected by the orbital overlap between the d-orbitals of the anchored metal atoms and the p-orbitals of the adsorbed C atom in FAL, suggesting that the selectivity of the C-O bond cleavage is inextricably related with the electronic property of the anchored metals.

Hydrogenation of furfuryl alcohol to tetrahydrofurfuryl alcohol on NiB/SiO_(2) amorphous alloy catalyst

NiB/SiO2 amorphous alloy catalyst was prepared by power electroless plating method and characterized by induction coupled plasma(ICP),Brunauer–Emmett–Teller method(BET),transmission electron microscope(TEM)and X-ray diffraction(XRD)techniques.The catalytic perfor-mance of NiB/SiO2 was investigated for the hydrogenation of furfuryl alcohol(FA)to tetrahydrofurfuryl alcohol(THFA).The effects of operational conditions,such as reaction tem-perature,pressure,and stirring rate were carefully studied.The proper conditions were determined as the following:pressure 2.0 MPa,temperature 120°C and stirring rate 550 r/min.A typical result with FA conversion of 99%and THFA selectivity of 100%was obtained under such conditions,which was close to that over Raney Ni.

Pt/CaO材料催化糠醇加氢制备戊二醇

通过浸渍法制备出一系列氧化钙负载铂金属催化材料,用于生物质基糠醇选择性加氢制备戊二醇研究。研究采用X射线衍射仪、扫描电子显微镜、CO_(2)-程序升温脱附、N2等温吸附-脱附、X射线光电子能谱、热重-差热分析法等一系列表征手段,对合成的催化剂样品物理化学性质进行了系统表征。实验结果表明,Pt/CaO-600催化剂表现出优异的催化活性,在4MPa氢压、210℃反应温度条件下,糠醇转化率为99.8%,1,2-戊二醇和1,5-戊二醇收率分别可达48.6%和21.5%。催化剂的优异性能可归因于作为载体的CaO提供了适宜的碱性位点,有利于糠醇开环反应的发生,进而提高了糠醇转化率与戊二醇选择性。同时,催化剂还表现出了优异的循环使用性能,经重复使用4次后,其催化糠醇转化率可达96.5%,1,2-戊二醇和1,5-戊二醇的收率分别为40.3%和17.0%。

咪唑二氰胺离子液体掺混糠醇的自燃及推进性能

利用落滴法对比了三种咪唑二氰胺离子液体分别掺混糠醇的自燃特性,使用高速摄相机和红外摄相机同步获得了燃料自燃过程的宏观、微观及红外图像;从液面下方拍摄了液滴与液池的混合反应过程。实验观察到了典型的三阶段自燃现象:铺展混合、气相产物生成及火核出现-火焰传播,使用着火延迟时间对燃料的自燃活性进行了定量表征,并计算了糠醇比例对混合燃料推进性能的影响。结果表明,糠醇添加可以显著降低混合燃料黏度,促进燃料与氧化剂的混合,加速自燃过程高温气雾产物的出现。混合燃料的着火延迟时间随糠醇添加比例非单调变化,着火延迟最短的掺混比随液滴速度的增加而增大;混合燃料推进性能受糠醇添加的影响较小。本研究可为自燃离子液体推进剂的开发及利用提供参考。

电化学合成2,5-二甲氧基-2,5-二氢呋喃甲醇工艺研究

以糠醇为原料,NaBr为电解质,甲醇为溶剂,利用电化学法合成焦袂康酸中间体2,5-二甲氧基-2,5-二氢呋喃甲醇,考察反应时间、NaBr添加量、反应温度对产率的影响。结果表明,反应时间与反应温度对产率有显著影响,NaBr添加量对产率影响不显著。当加入糠醇3 g(24 mmol),恒压15 V,最优条件为反应时间2.4 h,NaBr添加量为1.76 g,反应温度-10℃时,平均电流0.93 A,2,5-二甲氧基-2,5-二氢呋喃甲醇产率为67.9%。

液相法合成MOF-808催化糠醛转移加氢研究

采用简单易行的常压液相合成法,通过调节氧氯化锆和均苯三甲酸的比例,制备得到MOF-808-x,利用X-射线衍射(XRD)、傅里叶红外光谱(FT-IR)、场发射透射电子显微镜(TEM)等对其结构、形貌进行一系列表征。以糠醛加氢为探针反应,考察了MOF-808-x在异丙醇为氢供体体系中催化糠醛转移加氢制糠醇反应性能,并优化了反应条件。结果表明:合成催化剂适宜的原料配比可以提高反应活性。以MOF-808-1为催化剂时,在100℃反应2 h,糠醛转化率为100%,糠醇选择性>99%。

糠醇浸渍速生人工林木材的干燥特性研究

木材浸渍改性商业应用的主要技术难点之一是二次干燥速度慢、易开裂、易变形。本文以杨木和杉木为研究对象,使用浓度为30%和50%的糠醇水溶液对其进行浸渍改性,再以百度干燥法分析糠醇浸渍材的干燥特性,辅以干缩试验和剖面密度(VDP)试验探究干燥缺陷成因。结果表明:50%浓度浸渍材的干燥缺陷等级均大于30%浓度浸渍材,杨木浸渍材的等级均高于杉木浸渍材;杉木30%和50%浓度浸渍材百度干燥平均时间分别为24 h和29 h,而杨木30%和50%浓度浸渍材分别为20 h和30 h。浸渍材不同位置的干缩系数存在显著差异,浸渍后密度分布更加不均匀。杉木和杨木糠醇浸渍材二次干燥困难的主要原因为固化的糠醇堵塞了水分内部迁移通道,从而使干燥速度降低;糠醇分布不均匀导致干缩系数差异进一步加大,处理材易开裂、易变形。

温和条件下糠醇加氢催化剂性能的研究

本文选用Ru/C、Ru/Al_(2)O_(3)、Pd/C、Pd/Al_(2)O_(3)、Pt/C、雷尼镍等催化剂用于糠醇加氢的釜式反应研究。研究发现,Ru/C催化剂在糠醇加氢制备四氢糠醇的反应中具有良好的反应性能。研究了在Ru/C催化剂作用下溶剂、反应温度、氢气压力、反应时间、催化剂的用量等因素对反应的影响,并对工艺条件进行了优化。得到最佳工艺条件:异丙醇作溶剂,反应温度为60℃、氢气压力为3 MPa、反应时间为6 h,原料与催化剂的质量比为20:1,糠醇的转化率达到100%,四氢糠醇的选择性大于95%。

Catalytic transfer hydrogenation of biomass-derived furfural to furfuryl alcohol with formic acid as hydrogen donor over CuCs-MCM catalyst

Catalytic transfer hydroge nation(CTH)of furfural(FF)to furfu ryl alcohol(FFA)has received great intere st in recent years.He rein,Cu-Cs bimetallic supported catalyst,CuCs(2)-MCM,was developed for the CTH of FF to FFA using formic as hydrogen donor.CuCs(2)-MCM achieved a 99.6%FFA yield at an optimized reaction conditions of 170℃,1 h.Cu species in CuCs(2)-MCM had dual functions in catalytically decomposing formic acid to generate hydrogen and hydrogenating FF to FFA.The doping of Cs made the size of Cu particles smaller and improved the dispersion of the Cu active sites.Impo rtantly,the Cs species played a favorable role in enhancing the hydrogenation activity as a promoter by adjusting the surface acidity of Cu species to an appropriate level.Correlation analysis showed that surface acidity is the primary factor to affect the catalytic activity of CuCs(2)-MCM.

糠醛MPV还原制糠醇中固体酸碱催化剂的研究进展

介绍了固体酸碱催化剂在糠醛Meerwein-Ponndorf-Verley(MPV)还原制糠醇中的研究进展。糠醛作为高度商品化的生物基平台化合物,其可通过加氢还原为更具有经济价值的化学品。MPV还原因其条件温和、安全和环保而受到生物炼制领域青睐。介绍MPV典型反应及六元环过渡态的形成过程;对不同固体酸碱催化剂在糠醛MPV还原制糠醇中的研究进展进行总结,其中锆/铪基催化剂具有优异的MPV还原性能被广泛研究;针对固体酸碱催化剂在该领域进行总结,并指出存在的主要问题和解决方法,同时对该领域未来的发展进行展望。

Synthesis of a Rod-rod Diblock Copolymer, Poly (3-hexylthiophene)-block-poly(furfuryl isocyanate), through the Anionic Polymerization with an Oxyanionic Macroinitiator

A rod-rod diblock copolymer (diBCP), poly(3-hexylthiophene)-block-poly(furfuryl isocyanate)(P3HT-b-PFIC), was synthesized through the anionic polymerization with an oxyanionic macroinitiator of P3HT. The properties of the diBCP (molecular weight, dispersity, composition, thermal stability, UV-visible absorption, and thin film morphology) were determined by various analytical methods. P3HT-b-PFIC was blended with C60 in a toluene solution to prepare a thin film of binary electron donor/acceptor system. Such blending enabled partial conjugation of the two components by the Diels-Alder reaction between furan and C60 at 60℃ for 3 h;the mixture was then spin-cast as a thin film, and annealed at 250℃ for 24 h. Tapping-mode atomic force microscopy (AFM) revealed that P3HT and C60 domains had nanoscale interfaces without a large phase segregation. This result indicated that the microphase separation of C60-functionalized P3HT-b-PFIC preserved even at high temperature provided free C60 molecules with channels to diffuse on the sides of P3HT domain, thus preventing the macroscopic crystallization of free C60 through the interfacial stabilization.