Effect of Ceria Addition to Na2O-ZrO2 Catalytic Mixtures on Lignin Waste Ex-Situ Pyrolysis

Waste lignin is a potential source of renewable fuels and other chemical precursors under catalytic pyrolysis. For this purpose, four mixed metal oxide catalytic mixtures (Cat) derived from Na₂CO₃, CeO₂ and ZrO₂ were synthesised in varying compositions and utilised in a fixed bed reactor for catalytic vapour upgrading of Etek lignin pyrolysis products at 600 °C. The catalytic mixtures were analysed and characterised using XRD analysis, whilst pyrolysis products were analysed for distribution of products using FTIR, GC-MS and EA. Substantial phenolic content (20 wt%) was obtained when using equimolar catalytic mixture A (Cat_A), however the majority of these phenols were guaiacol derivatives, suggesting the catalytic mixture employed did not favour deep demethoxylation. Despite this, addition of 40–50% ceria to NaZrO₂ resulted in a remarkable reduction of coke to 4 wt%, compared to ~9 wt% of NaZrO₂. CeO₂ content higher than 50% favoured the increase in conversion of the holo-cellulose fraction, enriching the bio-oil in aldehydes, ketones and cyclopentanones. Of the catalytic mixtures studied, equimolar metal oxides content (Cat_A) appears to showcase the optimal characteristics for phenolics production and coking reduction.     

A review on the use of nanometals as catalysts for the thermal decomposition of ammonium perchlorate

In this review, an attempt to collect summarized literature data on catalytic effect of nanosized metals and nanoalloys on the thermal decomposition of ammonium perchlorates (AP) is made. Several experimental results show nanometals are more effective catalysts as compared to nanosized metal oxides. During decomposition process; metal react with oxygen containing species that are produced in decomposition process; and metal oxide is formed with large amount of heat which enhances the catalytic activity of metals as compared to metal oxide nanoparticles.     

以介孔分子筛为金属催化剂载体制备纳米碳管

 以不同的介孔分子筛作为金属催化剂载体,对催化合成纳米碳管进行了系统的研究,讨论了反应条件对纳米碳管纯度和产量的影响. 结果表明,不同的介孔分子筛对金属活性中心的形成、碳组分的扩散、纳米碳管的管径及形态均有明显的影响. 此外,金属的种类、状态和含量也影响纳米碳管的合成. 探索了合成高产量纳米碳管的条件,并对介孔分子筛上生长纳米碳管的特点进行了讨论.     

超临界水气化有机物制氢研究*

针对一些有机物的超临界水气化（SCWG）制氢过程,分别概述了模型有机物如葡萄糖、甲醇、纤维素、木质素和真实生物质及有机废物/水的影响因素、中间产物及反应路径;分析了均相催化剂如碱、碱金属盐和非均相催化剂如ZrO₂、活性碳、贵金属、过渡金属的催化气化效率及催化机理,并指出非均相催化SCWG过程是SCWG技术的重要发展方向;对SCWG制氢过程热力学进行初步的讨论;简要介绍了目前世界上的3套SCWG制氢中试装置的运行情况,提出SCWG过程工业化应用的难点及未来技术的发展方向。     

碱木质素在超临界水中Ru/C纳米管催化气化的降解研究

针对碱木质素难降解的特点,在间歇式反应器中,以Ru/C纳米管为催化剂,对碱木质素在超临界水中的气化进行研究。分别探讨了碱木质素在不同温度、水密度、反应时间、反应浓度、催化剂量的影响,并且分析了Ru/C纳米管催化剂的催化效率。通过单因素实验分析,确定了Ru/C纳米管催化剂催化气化碱木质素的最佳反应条件为,反应温度600 ℃、水密度0.128 4 g/cm³、反应时间60 min、反应质量分数3.0%、催化剂量0.5 g/g(碱木质素)。结果表明,碱木质素在超临界水气化过程中,高温、高水密度(或压力)、长反应时间、低反应物浓度及适量的催化剂将更有利于碱木质素的气化。在最佳反应条件下碱木质素的气化率和碳气化率分别达到73.74%和56.34%,且制氢能力也得到明显提高。     

Lignin bio-oil-based electrospun nanofibers with high substitution ratio property for potential carbon nanofibers applications

We reported a new approach for development of lignin bio-oil-based electrospun nanofibers (LENFs) that had high substitution ratio (up to 80 wt%) and good morphology. This approach was particularly unique and translatable as it used small molecule lignin bio-oil with high reactivity and low heterogeneity obtained via lignin depolymerization reaction to produce well-oriented LENFs. Firstly, effects of various blends solutions ratios and electrospinning parameters on the characteristics of the obtained LENFs were analyzed. The results showed that the optimal parameters that resulted in the best electrospun nanofibers were as follows: blend solution ratio, the 20 wt% blend solution containing 80 wt% straw lignin bio-oil (SLB) and 20 wt% polyacrylonitrile (PAN), flow rate, 1 mL/h, voltage, 20 kV, rotational speed, 500 r/min and the distance between needle and collection screen, 20 cm. Secondly, used the best LENFs, we also applied to prepare lignin bio-oil-based carbon nanofibers (LCNFs) and estimated its properties by scanning electron microscope (SEM), X-ray diffraction (XRD) patterns, Raman spectroscopy and tension testing. Our results demonstrated that compared with pure PAN carbon nanofibers (PCNFs), the as-prepared LCNFs had similar smooth surfaces, similar crystallinity and similar mechanical properties. This work can promote the utilization of lignin depolymerization main-products to produce lignin-based materials, while also help to reduce use of high-cost PAN.     

Effect of the order of Ni and Ce addition in SBA-15 on the activity in dry reforming of methane

Dry reforming of methane has been carried out on SBA-15 catalysts containing 5 wt% Ni and 6 wt% Ce. The effect of the order of Ni and Ce impregnation on the catalytic activity has been studied. Both metals were added using the “two-solvent” method that favors metal dispersion inside the pores. Characterizations by XRD (low and high angles), N₂ sorption, SEM and TEM of the materials after metal addition and calcination indicate good preservation of the porosities and high NiO and CeO₂ dispersion inside the porous channels. Reduction was carried out before the catalytic tests and followed by TPR measurements. The most active reduced catalyst was the Ni–Ce/SBA-15 sample prepared by impregnating cerium first, then nickel. All catalysts were highly active and selective towards H₂ and CO at atmospheric pressure. Full CH₄ conversion was obtained below 650 °C. The higher performances compared to those reported in the literature for mesoporous silica with supported Ni and Ce catalysts are discussed.     

Metal compound-enhanced flame retardancy of intumescent epoxy resins containing ammonium polyphosphate

A series of intumescent flame-retardant epoxy resins (IFR-EPs) were prepared only by adding a 5 wt% total loading of ammonium polyphosphate (APP) and metal compounds. All the samples could achieve V-0 rating and did not generate dripping during UL-94 testing. The limiting oxygen index (LOI) values of the samples with 4.83 wt% APP and 0.17 wt% CoSA increase from 27.1 to 29.4, compared with epoxy resin containing 5 wt% APP. The samples also showed excellent water resistance of flame retardancy in 30 °C and 70 °C water for 168 h. The LOI results show that the composition of metal compounds (metal ions and ligands/anions) and the mass ratios of APP to metal compounds affect the flame retardancy of the samples. TG results indicate that the catalytic effect of CoSA on the decomposition of both APP and the epoxy resins containing APP is better than that of CuSAO. The fire behavior of epoxy resin and epoxy resins containing APP with/without CoSA were investigated by cone calorimeter. Cone calorimeter parameters of the samples such as HRR, THR, TSP and COP indicate that the addition of APP and CoSA improves the fire safety of epoxy resin significantly, and CoSA shows an obvious catalytic effect.     

Al2O3负载Cu,Fe或Ni掺杂氧化钼催化乙苯氧化脱氢（英文）

Molybdenum-based catalysts supported on Al2O3 doped with Ni, Cu, or Fe oxide were synthesized and used in ethylbenzene dehydrogenation to produce styrene. The molybdenum oxide was sup-ported using an unconventional route that combined the polymeric precursor method (Pechini) and wet impregnation on commercial alumina. The samples were characterized by X-ray diffraction (XRD), N2 adsorption-desorption isotherms, temperature-programmed reduction of H2 (H2-TPR), and thermogravimetric (TG) analysis. XRD results showed that the added metals were well dis-persed on the alumina support. The addition of the metal oxide (Ni, Cu, or Fe) of 2 wt% by wet im-pregnation did not affect the texture of the support. TPR results indicated a synergistic effect be-tween the dopant and molybdenum oxide. The catalytic tests showed ethylbenzene conversion of 28%–53% and styrene selectivity of 94%–97%, indicating that the addition of the dopant improved the catalytic performance, which was related to the redox mechanism. Molybdenum oxides play a fundamental role in the oxidative dehydrogenation of ethylbenzene to styrene by its redox and acid–base properties. The sample containing Cu showed an atypical result with increasing conver-sion during the reaction, which was due to metal reduction. The Ni-containing solid exhibited the highest amount of carbon deposited, shown by TG analysis after the catalytic test, which explained its lower catalytic stability and selectivity.     

组合催化剂WO3+Raney Ni上高效转化菊芋秸秆制乙二醇

采用商业WO₃和Raney Ni为组合催化剂, 以菊芋秸秆为反应原料制备了乙二醇. 菊芋秸秆中含纤维素51.6 wt%、半纤维素10.3 wt%、木质素17.2 wt%、灰分1.7 wt%和水溶性物质19.2 wt%. 木质素对纤维素和半纤维素的转化影响较小, 而水溶性物质的存在抑制了乙二醇的生成, 因此由未经过预处理的菊芋秸秆得到的乙二醇收率只有29.9%. 而经简单的热水预处理可除掉其中的大部分水溶物, 因而乙二醇收率提高到37.6%. 此外, 组合催化剂在经过热水预处理的菊芋秸秆的转化中表现出了更好的循环使用性能. 同时考察了反应温度和时间对菊芋秸秆转化的影响.     

Catalytic conversion of lactic acid into propylene glycol over various metals supported on silica

Catalytic hydrogenation of lactic acid to propylene glycol was performed over various metals (Ag, Co, Cu, Ni, Pt, and Ru) supported on silica prepared by an incipient wetness impregnation method. The loading amount of each metal was 5 wt%. Crystallinity of the synthesized catalysts was investigated by X-ray diffraction (XRD), and the BET method was utilized to examine the surface area. Pore volume and pore size of catalysts were determined using BJH analysis of the N₂ adsorption isotherm. Particle sizes of various metals were determined from transmission electron microscopy (TEM) images. The catalytic activity was found to be strongly dependent on the supported metal. Among catalysts tested, Ru/SiO₂ showed the highest propylene glycol yield. The yield of propylene glycol increased with pressure, and the highest yield was achieved at 130 °C.     

Synthesis of Cumene from Lignin by Catalytic Transformation

Cumene is an important intermediate and chemical in chemical industry.In this work,directional preparation of cumene using lignin was achieved by a three-step cascade process.The mixture aromatics were first produced by the catalytic pyrolysis of lignin at 450℃ over 1% Zn/HZSM-5 catalyst,monocyclic aromatics with the selectivity of 85.7 wt% were obtained.Then,the catalytic dealkylation of heavier aromatics resulted in benzene-rich aromatics with 93.6 wt% benzene at 600℃ over Hβ catalyst.Finally,the cumene synthesis was performed by the aromatic alkylation,giving cumene selectivity of 91.6 C-mol% using the[bmim]Cl-2AlCl₁₃ ionic liquid at room temperature for 15 min.Besides,adding a small amount of methanol to the feed can efficiently suppress the coke yield and enhance the aromatics yield.The proposed transformation potentially provides a useful route for production of cumene using renewable lignin.     

Lignin-Derived Syringol and Acetosyringone from Palm Bunch Using Heterogeneous Oxidative Depolymerization over Mixed Metal Oxide Catalysts under Microwave Heating

Biomass valorization to building block chemicals in food and pharmaceutical industries has tremendously gained attention. To produce monophenolic compounds from palm empty fruit bunch (EFB), EFB was subjected to alkaline hydrothermal extraction using NaOH or K₂CO₃ as a promotor. Subsequently, EFB-derived lignin was subjected to an oxidative depolymerization using Cu(II) and Fe(III) mixed metal oxides catalyst supported on γ-Al₂O₃ or SiO₂ as the catalyst in the presence of hydrogen peroxide. The highest percentage of total phenolic compounds of 63.87 wt% was obtained from microwave-induced oxidative degradation of K₂CO₃ extracted lignin catalyzed by Cu-Fe/SiO₂ catalyst. Main products from the aforementioned condition included 27.29 wt% of 2,4-di-tert-butylphenol, 19.21 wt% of syringol, 9.36 wt% of acetosyringone, 3.69 wt% of acetovanillone, 2.16 wt% of syringaldehyde, and 2.16 wt% of vanillin. Although the total phenolic compound from Cu-Fe/Al₂O₃ catalyst was lower (49.52 wt%) compared with that from Cu-Fe/SiO₂ catalyst (63.87 wt%), Cu-Fe/Al₂O₃ catalyst provided the greater selectivity of main two value-added products, syringol and acetosyrigone, at 54.64% and 23.65%, respectively (78.29% total selectivity of two products) from the NaOH extracted lignin. The findings suggested a promising method for syringol and acetosyringone production from the oxidative heterogeneous lignin depolymerization under low power intensity microwave heating within a short reaction time of 30 min.     

1-辛烯在Co/CNTs催化剂上的氢甲酰化研究： 钌的促进作用

采用等体积浸渍法制备了碳纳米管负载的钴及钴-钌双金属催化剂，并以1-辛烯的氢甲酰化反应为探针，研究了所制催化剂的催化性能；用TEM、XRD、TPR、TG技术对催化剂的形貌、物相结构、还原行为和热稳定性进行了研究。结果表明，金属钌能够促进金属钴在碳纳米管上的均匀担载，并有助于金属钴的还原，降低了催化剂的还原温度。1-辛烯的氢甲酰化反应结果表明，少量钌的加入，可明显提高反应的转化率和C9-醛的选择性；在双金属催化剂中，金属催化剂的粒径更小，分布更均匀，钌的加入对钴金属催化剂有促进作用。     

Well-Dispersed Trifluoromethanesulfonic Acid-Treated Metal Oxide Nanoparticles Immobilized on Nitrogen-Doped Carbon as Catalysts for Friedel–Crafts Acylation

Although strong acid-treated metal oxides are useful heterogeneous superacid catalysts for various organic transformations, they usually have a limited density of acidic sites due to their low surface areas. Herein, heterogeneous trifluoromethanesulfonic acid immobilized nitrogen-doped carbon-incarcerated titanium nanoparticle (NP) catalysts have been developed that are composed of well-dispersed, small Ti NPs (ca 7 nm) that are otherwise difficult to achieve using acid-treated metal oxides. The catalysts showed high activity for Friedel–Crafts acylation with low titanium loading (2 mol%, <1 mg of metal for 1 mmol of substrate). A range of microscopic, spectroscopic and physicochemical studies revealed that the nitrogen-doped carbon immobilized the trifluoromethanesulfonic acid and that the addition of metals further changed the nature of the acidic species and enhanced catalytic activity.     

Lignin conversion to hydrogen-containing gas under the action of microwave radiation

The paper describes the carbon dioxide reforming of lignin in the presence of Ni-, Fe, and Ni/Fe-containing active components formed directly on the surface under microwave irradiation. The deposition of 0.1 wt % iron acetylacetonate on the lignin surface results in a sharp increase in the microwave absorption capacity at a 0.5 kW power and induces lignin conversion to hydrogen-containing gas with a degree of hydrogen recovery reaching 90 %. The maximum lignin conversion (65%) is attained in 10 min under microwave irradiation. It was shown for the first time that deposition of metals (Fe and Ni) on lignin can provide for targeted change of the selectivity of reforming to synthesis gas and the process can thus be classified as a plasma catalytic one. Using the obtained results, it is possible to minimize the amount of catalyst and to propose an efficient route for hydrogen and synthesis gas production from lignin waste.     

Activation of Carbon Dioxide and Synthesis of Propylene Carbonate

Cycloaddition of carbon dioxdie and propylene oxide to propylene carbonate catalyzed by tetra-tert-butyl metal phthalocyanine in the presence of tributylamine(TBA) shows higher yield than catalyzed by unsubstituted metal phthalocyanine.Comparing different catalysts of diverse metals,(t-Bu)4PcMg is more active than (t-Bu)PcFe ,But(t-Bu)4PcCo and (t-Bu)4PcNi only have low catalytic activities towards the reaction.Moreover,the yield will increase as the temperature increases.     

过渡金属掺杂亚铁锌双金属氰化物催化合成生物柴油的研究

研究了掺杂过渡金属盐(La、Ce、Zr、Mn)对亚铁锌双金属氰化物(DMC)固体酸催化剂合成生物柴油的影响,并采用XRD、FT-IR、ICP、BET等方法对其进行结构和性能表征。结果表明,1%的镧、铈、锆、锰金属盐对催化剂的活性都有提高,其中,添加1%镧的DMC催化剂活性最高,在醇油摩尔比16∶1,反应温度160 ℃,催化剂加入量2%条件下,反应7 h,脂肪酸甲酯收率达到99.3%。过渡金属盐引入对催化剂的组成没有影响,但使得催化剂更加分散,颗粒粒径更小,比表面积变大,有利于催化剂和反应物的接触,从而提高了催化剂活性。     

化学镀镍诱发过程的研究 I:金属催化活性的鉴别和反应机理

Electroless plating is known to be an autocatalytic process. For the reaction to start, the substrate metall should be either catalytic or activated by a suitable catalyst. For example, steel and nickel can be plated directly, but in the case of copper or brass, catalytic metal inducing is need. In this paper, the catalytic activity of different metals and their inducing effects were in vestigated by measuring stationary potentials nd stationary potential-time curves. Experimental results showed: (1) The stationary potential of metal provides a simple parameter to estimate the catalytic activity of metals in electroless nickeling. When 1-hydroxyethylidenediphosphonic acid (HEDP) aelectroless nickeling bath containing NaH2PO2 as reducing agent is used, electrolessnickeling may proceed spontaneously, if the stationary potential of metal is more nagative than -0.60V, no matter whether nickel (autocatalytic active) or other metals(non-autocatalytic active) is used as substrate. (2)When an autocatalytic meta is in contact with the substrate metal in the bath, a sudden decrease of stationary potential is observed. The whole inducing process could be finished within 0.5-2 sec. (3) The stationary potential of electroless nickeling coating in HEDP bath at 80`C is-0.72V, consequently nickel coating itself is a catalytic active metal. Once an electroless nickeling coating is deposited on a substrate metal, electroless nickeling reaction can then proceed continuously. (4) The sufficient conditions of electroless nickeling in HEDP bath containing NaH2PO2 are that the stationary potential of substrate metal must be more nagative than -0.60V and that the temperature of electroless nickeling bath should be higher than 50`C. (5) Inducing mechanism of electroless nickeling can be explained with chemical cell consisting of substrate metal and catalytic metal. Electrons from catalytic metal would suddenly decrease the stationary potential of substrate metal, H+ and Ni2+ complex ion would be reduced on the substrate me