Combination Of Catalyst Research Articles

Dehydration of Glucose to 5-Hydroxymethylfurfural Using Combined Catalysts in Ionic Liquid by Microwave Heating

The dehydration of glucose into 5-hydroxymethylfurfural (HMF) was catalyzed by NKC-9 (a macroporous sulfonated polystyrene ion-exchange resin) combined with metal oxides (TiO2, ZrO2, Al2O3 calcined at different temperatures). In the combined catalytic system, Al2O3 calcined at 550°C exhibited excellent catalytic activity, when the dosage of NKC-9 was kept constant. Four parameters (catalyst dosage, reaction temperature, reaction time, and initial glucose amount) were optimized by employing response surface methodology (RSM), with HMF yield as the response parameter. The maximum HMF yield of 62.09% was obtained at catalyst 0.07 g, temperature 140°C, time 20 min, and glucose 0.01 g. The catalytic activity of the binary catalyst (NKC-9 and Al2O3) for the conversion of glucose into HMF did not show significant decrease after five-times uses at 140°C for 20 min.

ChemInform Abstract: Efficient Oxidative Cleavage of Tetrahydrofuran‐2‐methanols to γ‐Lactones by a 2‐Iodobenzamide Catalyst in Combination with Oxone®.

ChemInformVolume 47, Issue 30 Heterocyclic Compounds ChemInform Abstract: Efficient Oxidative Cleavage of Tetrahydrofuran-2-methanols to γ-Lactones by a 2-Iodobenzamide Catalyst in Combination with Oxone®. Takayuki Yakura, Takayuki Yakura Grad. Sch. Med. Pharm. Sci., Toyama Univ., Sugitani, Toyama 930-0194, JapanSearch for more papers by this authorYuto Horiuchi, Yuto Horiuchi Grad. Sch. Med. Pharm. Sci., Toyama Univ., Sugitani, Toyama 930-0194, JapanSearch for more papers by this authorYushi Nishimura, Yushi Nishimura Grad. Sch. Med. Pharm. Sci., Toyama Univ., Sugitani, Toyama 930-0194, JapanSearch for more papers by this authorAkihiro Yamada, Akihiro Yamada Grad. Sch. Med. Pharm. Sci., Toyama Univ., Sugitani, Toyama 930-0194, JapanSearch for more papers by this authorHisanori Nambu, Hisanori Nambu Grad. Sch. Med. Pharm. Sci., Toyama Univ., Sugitani, Toyama 930-0194, JapanSearch for more papers by this authorTomoya Fujiwara, Tomoya Fujiwara Grad. Sch. Med. Pharm. Sci., Toyama Univ., Sugitani, Toyama 930-0194, JapanSearch for more papers by this author Takayuki Yakura, Takayuki Yakura Grad. Sch. Med. Pharm. Sci., Toyama Univ., Sugitani, Toyama 930-0194, JapanSearch for more papers by this authorYuto Horiuchi, Yuto Horiuchi Grad. Sch. Med. Pharm. Sci., Toyama Univ., Sugitani, Toyama 930-0194, JapanSearch for more papers by this authorYushi Nishimura, Yushi Nishimura Grad. Sch. Med. Pharm. Sci., Toyama Univ., Sugitani, Toyama 930-0194, JapanSearch for more papers by this authorAkihiro Yamada, Akihiro Yamada Grad. Sch. Med. Pharm. Sci., Toyama Univ., Sugitani, Toyama 930-0194, JapanSearch for more papers by this authorHisanori Nambu, Hisanori Nambu Grad. Sch. Med. Pharm. Sci., Toyama Univ., Sugitani, Toyama 930-0194, JapanSearch for more papers by this authorTomoya Fujiwara, Tomoya Fujiwara Grad. Sch. Med. Pharm. Sci., Toyama Univ., Sugitani, Toyama 930-0194, JapanSearch for more papers by this author First published: 07 July 2016 https://doi.org/10.1002/chin.201630122Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume47, Issue30July, 2016 RelatedInformation

HYDROGEN PRODUCTION FROM STEAM PYROLYSIS-GASIFICATION OF SUGARCANE LEAVES WITH SORBENT-CATALYSTS

In this work, the hydrogen production during biomass steam pyrolysis-gasification with a combined catalysts and sorbent. The biomass sample was originated from sugarcane leaves. The combined catalyst and sorbent (NiO-MgO-CaO/γ-Al2O3) was prepared by an excess-solution impregnation method and the property of fresh and used catalysts was characterized using XRD. The prepared sorbent-catalysts promoted both tar reforming and CO2 absorption. High hydrogen production was achieved due to the enhanced water–gas shift reaction by the latter. The pyrolysis-gasification experiments were conducted in a drop tube two-stage fixed bed reactor. The effect of operating parameters such as the amount of MgO (3, 5 and 10 wt.%) and CaO (3, 5 and 10 wt.%) on supported catalysts and the gasification temperatures (600, 700 and 800 oC) were investigated. It was found that the highest hydrogen yield of 23.2 mmol H2/gbiomass was attained using the Ni10Mg5Ca5 catalyst at the gasification temperature of 600 oC. However, the maximum of tar conversion was observed around 78 wt.% at gasification temperature up to 800 oC.

Catalyst-Free Insertion of Sulfoxonium Ylides into Aryl Thiols. ADirect Preparation of β-Keto Thioethers.

Insertion of sulfoxonium ylides into the S-H bond of aryl thiols without the need for a catalyst is demonstrated, furnishing β-keto thioethers in excellent yield in most cases. The method overcomes traditional syntheses that employ metal catalysts in combination with diazo compounds or toxic and hard-prepared haloketones. The experimental setup consists of mixing the reagents in acetonitrile at room temperature. Additional experimental as well as kinetic isotopic effect studies give some insight into the mechanism of this reaction.

ChemInform Abstract: Highly Efficient Transition Metal Nanoparticle Catalysts in Aqueous Solutions.

AbstractA tris(triazolyl)‐polyethylene glycol amphiphilic ligand is designed and successfully used as highly efficient catalyst in combination with various transition metal nanoparticles in click reactions, Suzuki—Miyaura couplings, as well as transfer hydrogenation reactions.

New Insights into the Mechanism of Synergistic Effect for [CeO2–ZrO2 + H-Beta] CombiCat in NH3–SCR

NH3–SCR performance of the combined catalyst (CombiCats) prepared by mechanical mixing of CeO2–ZrO2 and H-Beta is studied in details. It was shown, that individual standard SCR activities of CeO2–ZrO2 and H-Beta are negligible, while their mixing results in the significant improvement of NOx conversion. The absence of standard SCR activity of individual components enabled us to estimate the contribution of fast SCR, NO and NH3 oxidation reactions to the overall process on CombiCat. Comparison of catalytic data obtained for layered configurations and CombiCats with various CeO2–ZrO2/H-Beta ratios also allowed us to determine the rate-limiting step and role of each component in the process.

ChemInform Abstract: Carbon Dioxide/Epoxide Reactions Catalyzed by Bimetallic Salalen Aluminum Complexes.

AbstractThe salen complex catalyst (SAA) in combination with Bu4NBr as co‐catalyst shows high catalytic activity in reactions of epoxides (I) and (IV) with carbon dioxide to give the corresponding carbonates.

Hydrogenolysis/hydrogenation of diphenyl ether as a model decomposition reaction of lignin from biomass in pressurized CO2/water condition

Catalytic hydrogenolysis of the CO bond of diphenyl ether (a lignin model compound) was investigated as a function of hydrogen pressure in scCO2 medium in the presence of water. Using commercially available Rh/C catalyst, the CO bond cleavage of diphenyl ether mainly results phenolic monomer at 80°C. Hydrogen pressure is one of the key parameters because (i) CO bond cleavage and the hydrogenation of aromatic rings are two competitive reactions; very sensitive to hydrogen pressure and (ii) hydrogen has complete solubility in scCO2. Therefore, a critical control of hydrogen pressure was essential to reach the targeted cleavage of the CO bond when the reaction was conducted in scCO2 medium under pressurized condition. Depending on the hydrogen pressure, a significant change in the ratio of monocyclic:bicyclic products from 91:9 (0.2MPa) to 58:42 (2MPa) was revealed in the shortest reaction time of 5min. Thus, low hydrogen pressure was the effective choice for the scission of the CO bond, whereas higher hydrogen pressure hydrogenate the aromatic ring due to the higher coverage of hydrogen on the catalytic surface. Amount of the catalyst (catalyst:substrate ratio) displayed a subtle effect on the breakage of the CO bond. A threshold ratio of 1:5 was preferred under the present reaction condition as the increased amount hampered the substrate:water ratio and hydrogenation of the aromatic ring occurred. In addition, as the change in temperature is associated with the change in the physical properties of scCO2, hence, the effect on the transformation of DPE was complicated and difficult to explain. Furthermore, different organic solvents as neat, along with CO2 and with water also has substantial impact on the rapture of CO bond. The obtained results from the solvent studies again proved that scCO2 along with water was the best choice for CO bond breakage and water is the driving force to mediate the reaction. In addition, a combination catalyst (Ni+Rh) was also tested for the same reaction under the similar working condition. Preliminary results suggested a synergistic effect in terms of the selectivity of monocyclic compounds.

The effect of trace amounts of copper on the microstructure, stability and oxidation of macroporous silicon carbide

Trace amounts of copper have advantageous effects when creating macroporous silicon carbide monoliths to be used for combined diesel particle filter and catalyst support systems. These structures were produced from a slurry of silicon, graphite, aluminium and copper. Mixed with water, extruded and dried, the resulting bodies were pyrolyzed, sintered, and then partially oxidized, to yield a mechanically stable porous 4H-SiC microstructure with an average pore diameter of 20μm and average accessible porosity of 57%. The Cu alloys with the Si and Al to create the sintered body via a liquid phase, and prevents the build-up of undesirable Al-containing ternary carbide crystals in the microstructure. The Cu promotes oxidation of SiC to form a 80nm SiO2 layer that serves as a good catalyst support. The accelerated oxidation can be intercepted by dissolving the Cu component from the monoliths with an acid solution.

Diesel oil-like hydrocarbon production from vegetable oil in a single process over Pt–Ni/Al2O3 and Pd/C combined catalysts

Diesel oil-like hydrocarbon production from vegetable oil (sunflower oil) was addressed in a single process using a catalytic fixed-bed pressure reactor, operating in batch wise under subcritical water conditions without external hydrogen supplied. The process has been decoupled identifying the sequential steps involved in the whole reaction. The non-catalytic hydrolysis of triglycerides to form fatty acids (FFA) and glycerol, the aqueous phase reforming of glycerol and the in situ hydrogenation and deoxygenation of the unsaturated fatty acids are the reactions involved to form diesel oil-like hydrocarbons. Under subcritical water condition, the Pt–Ni/Al2O3 catalyst promotes the glycerol reforming, the complete hydrogenation and the partial deoxygenation of the FFA. The combination of Pt–Ni/Al2O3 and Pd/C catalysts as a double fixed-bed allowed a further decarboxylation of FFA to form a C17-paraffinic hydrocarbon: cetane number of 48.8, density of 0.774g·cm−3 and higher heating value of 47.53MJ·kg−1; comparable to commercial hydrotreated vegetable oil (HVO).

A Combined Catalyst of Pt Nanoparticles and TiO2 with Water‐Tolerant Lewis Acid Sites for One‐Pot Conversion of Glycerol to Lactic Acid

AbstractCatalytic conversion of glycerol to valuable chemicals has been recognized as an attractive and challenging reaction in biorefinery. In this paper, we demonstrated that a combined catalyst of Pt nanoparticles and TiO2 worked as a highly active catalyst for the one‐pot conversion of glycerol to lactic acid in water. The yield of lactic acid reached 63 % under oxygen atmosphere without the use of any additives such as strong bases, and the catalyst could be reused without significant loss of the catalytic performance. The mechanistic studies revealed that Pt nanoparticles on TiO2 selectively oxidized glycerol to C3 aldehyde/ketone, and Lewis acid sites on TiO2 smoothly promoted the dehydration and rehydration/rearrangement reactions of the intermediates to produce lactic acid efficiently.

Efficient Oxidative Cleavage of Tetrahydrofuran‐2‐methanols to γ‐Lactones by a 2‐Iodobenzamide Catalyst in Combination with Oxone®

AbstractAn environmentally friendly oxidative cleavage of tetrahydrofuran‐2‐methanols to the corresponding γ‐lactones using a catalytic amount of 2‐iodo‐N‐isopropylbenzamide has been developed. The reaction of various tetrahydrofuran‐2‐methanols with the catalyst in the presence of Oxone® (2 KHSO5⋅KHSO4⋅K2SO4) as a co‐oxidant in DMF at room temperature successfully affords the corresponding lactones in good to high yields, and recovery of the catalyst is readily accomplished using a reductive work‐up. This method is notable because it enables the transformation of tetrahydrofuran‐2‐methanols to γ‐lactones under mild conditions without the use of any toxic heavy metals.magnified image

Synthesis of Fe-doped Bi2O3 nanocatalyst and its sonophotocatalytic activity on synthetic dye and real textile wastewater.

The catalysts such as Fe, Bi2O3, and Fe-doped Bi2O3 were synthesized for the sonophotocatalytic treatment of synthetic dye and real textile wastewater. The resultant catalysts were characterized for its size and uniform shape using x-ray diffractogram (XRD) and scanning electron microscopy (SEM) which signified the nanorod shape formed Bi2O3. The higher ultraviolet light absorbance capacity of the catalysts was also evident using diffuse reflectance spectroscopy (DRS). Initially, the effect of conventional parameters such as initial pH, gas bubbling (argon, oxygen, air and nitrogen) and oxidant addition (H2O2 and peroxymonosulfate) in the presence of sonolysis (22 and 37kHz frequency) and photolysis (UV-C light) on 10ppm Basic Brown 1 dye was studied. The results showed that highest decolorization of 62% was attained for 3g/L peroxymonosulfate under 37kHz frequency sonolysis treatment. Secondly, with the catalyst study, highest of 46% dye color removal was obtained with 4g/L Fe under 37kHz frequency sonolysis treatment. The sonophotocatalytic treatment of dye with Fe-doped Bi2O3 catalyst in combination with peroxymonosulfate showed highest color removal of 99%. Finally, the sonophotocatalytic treatment of real textile wastewater in the presence of 3g/L Fe-doped Bi2O3 and 6g/L peroxymonosulfate reduced the total organic carbon (TOC) and chemical oxygen demand (COD) level to 77 and 91%, respectively, in 180min. The reported treatment process was found to treat the synthetic dye and real textile wastewater effectively.

Hydrogenolysis of glycerol over Pt/C catalyst in combination with alkali metal hydroxides

AbstractThe hydrogenolysis of glycerol was performed over a Pt/C catalyst in combination with several alkali metal hydroxides and their salts. LiOH was found to be an effective promoter for the selective hydrogenolysis of glycerol to 1,2-propanediol. Hydroxyl ions are the main factor to promote the reaction process by dehydration of the glyceraldehyde intermediate. Lithium ions play a role in assisting the dehydrogenation of glycerol to glyceraldehyde, because they have the right size to coordinate with the alkoxide species. A possible surface reaction mechanism involving the participation of lithium ions was proposed to account for the results obtained in the study.

Carbon Nanotubes Synthesis from Four Different Organic Precursors by CVD

ABSTRACTCarbon nanotubes (CNTs) were synthesized by Chemical Vapor Deposition (CVD) from diethyl ether, butanol, hexane and ethyl acetate. A quartz tube with a stainless steel tube catalyst core with 0.019 m diameter and 0.6 m large formed the reactor. To avoid combustion, argon was used as the carrier gas. Time process ranged 30 to 60 min. The range of CNTs synthesis temperature was 680-850 °C for different precursors. Scanning Electron Microscopy micrographs have demonstrated tangled CNTs growth in all samples, thus presenting difficult length measurement. The CNTs diameters from diethyl ether are 45-200 nm, butanol diameter range from 55-230 nm, hexane diameter range is 50-130 nm and ethyl acetate range from 100 to 300 nm. Carbon content for all samples was higher than 93 %, CNTs from butanol showed carbon concentration up to 99%. FTIR, Raman and X-Ray Spectroscopies spectra for all samples demonstrated the characteristics signals present in carbon nanotubes. This research proposes a simple, effective and innovative method to synthesize CNTs by CVD on iron stainless steel catalyst in combination with diethyl ether, ethyl acetate, butanol and hexane as precursors by applying the principles of green chemistry, sustainability and its ease to be scaled.

Synthesis of esters via sp(3) C-H functionalisation.

Oxidative C-O bond formation via sp(3) C-H functionalisation represents an attractive approach for the synthesis of esters. This review focuses on the recent advances of sp(3) C-H bond functionalisation strategies for ester synthesis from unconventional precursors using transition metal/metal free catalysts in combination with various oxidants. Various classes of esters and the mechanisms of their formation are discussed with numerous examples.

Highly selective hydrogenation and hydrogenolysis using a copper-doped porous metal oxide catalyst

A copper-doped porous metal oxide catalyst in combination with hydrogen shows selective and quantitative hydrogenolysis of benzyl ketones and aldehydes, and hydrogenation of alkenes.

Borrowing Hydrogen法による効率的分子変換反応：複素環化合物の選択的アルキル化反応とアミノアルコール類の合成

Our efficient catalytic reactions based on the “Borrowing Hydrogen” methodology are described here. Thus, indoles were reacted with alcohols in the presence of Pd/C or RuCl2(PPh3)3/DPEphos catalyst to give the corresponding 3-alkylindoles in good to excellent yields. The Pd/C catalysis also promoted the regioselective alkylation of 4-hydroxycoumarin, barbituric acids and oxindoles with good catalytic efficiency. Reaction of amines with 1,2-diol in the presence of [RuCl2(p-cymene)]2/JOSIPHOS catalyst afforded the optically active β-amino alcohols with up to 77% ee. Highly efficient hydroamination of C-C double bond of allylic alcohols was achieved with a combination catalyst of RuClH(CO)(PPh3)3 and a pyridine ligand bearing two imine units at its 2,6-position to provide the corresponding γ-amino alcohols in high yield.

Thermally amendable and thermally stable thin film of POSS tethered Poly(methyl methacrylate) (PMMA) synthesized by ATRP

In this article we report the stability, dewetting suppression and scratch mending of thin film of POSS tethered PMMA hybrid material having thickness in the range of 100–300nm. The POSS–PMMA hybrid material was synthesized via thermal thiol-ene modification of allyl-POSS followed by O-acylation reaction and atom transfer radical polymerization (ATRP). The polymerization reaction was carried out using CuBr as catalyst in combination with N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA) as ligand, and POSS–Br as initiator. NMR, FT-IR, WAXD and FE-SEM analyses were used to study the structure and morphology of the hybrid materials. FE-SEM analysis showed interesting honeycomb architecture in the hybrid material. Subsequently we investigated the thermal stability and scratch mending (SM) of spin cast thin films of the synthesized POSS–PMMA hybrid material. The as cast film had a holey, Swiss cheese morphology when dispersed from a rapidly evaporating solvent THF. The film, upon thermal annealing flattened out in favor of a smooth, featureless film that did not dewet with time even upon prolonged annealing. Further, scratches made on the film surface using a scalpel were seen to mend completely upon prolonged thermal annealing at temperatures above Tg of the polymer. The film could mend repeated scratches at the same location with complete recovery of mechanical strength, which was verified by nano-indentation measurement. The mending is entirely due to wetting of the polymer film in presence of low surface energy POSS. The scratch mending was slow, but was observed during repeated mending cycles. The films also exhibited improved hydrophobicity which remains un-altered even upon repeated mending cycles indicating presence of POSS moieties in the film surface. Importantly, when scratches made on the pristine PMMA film surface using a scalpel, the film was found to be ruptured during annealing due to strong influence of the dispersion forces across the low thickness zone and consequently, the film dewetted and the scratch width gradually increased with time.

Effects of Secondary Metal Carbonate Addition on the Porous Character of Resorcinol-Formaldehyde Xerogels.

A deeper understanding of the chemistry and physics of growth, aggregation, and gelation processes involved in the formation of xerogels is key to providing greater control of the porous characteristics of such materials, increasing the range of applications for which they may be utilized. Time-resolved dynamic light scattering has been used to study the formation of resorcinol-formaldehyde gels in the presence of combinations of Group I (Na and Cs) and Group II (Ca and Ba) metal carbonates. It was found that the combined catalyst composition, including species and times of addition, is crucial in determining the end properties of the xerogels via its effect on growth of clusters involved in formation of the gel network. Combination materials have textural characteristics within the full gamut offered by each catalyst alone; however, in addition, combination materials that retain the small pores associated with sodium carbonate catalyzed xerogels exhibit a narrowing of the pore size distribution, providing an increased pore volume within an application-specific range of pore sizes. We also show evidence of pore size tunability while maintaining ionic strength, which significantly increases the potential of such systems for biological applications.