Epoxidation of allyl alcohol with hydrogen peroxide over titanium silicalite TS‐2 catalyst

The influence of the technological parameters on the course of the epoxidation of allyl alcohol with 30% H₂O₂ in the presence of titanium silicalite TS‐2 catalyst and methanol as a solvent was studied. The process was performed in an autoclave at the autogenic pressure. The influence of temperature in the range 20–120 °C, molar ratio of allyl alcohol/H₂O₂ (1:1–10:1), methanol concentration in the reaction mixture (10–80% w/w), catalyst TS‐2 concentration (0.1–2.0% w/w) and reaction time (1–8 h) were investigated. The functions describing the process were: selectivity of transformation to glycidocidol in relation to allyl alcohol consumed, selectivity of transformation to organic compounds in relation to hydrogen peroxide consumed, conversions of allyl alcohol and hydrogen peroxide. Copyright © 2007 Society of Chemical Industry     

Au/TS‐1 catalyst for propene epoxidation with H2/O2: A novel strategy to enhance stability by tuning charging sequence

For propene epoxidation with H₂ and O₂, the catalytic performance of Au/TS‐1 catalyst is extremely sensitive to preparation parameters of deposition‐precipitation (DP) method. In this work, effect of charging sequence in DP process on catalyst structure and catalytic performance of Au/TS‐1 catalyst is first investigated. For different charging sequences, the compositions of Au complexes (e.g., [AuCl(OH)₃]^?) and pore property of TS‐1 (i.e., with or without H₂O prefilling micropores) could affect the transfer of Au complexes into the micropores, resulting in different Au locations and thus significantly different catalytic performance. Notably, when TS‐1 is first filled with H₂O and then mixed with Au complexes, the reduced Au/TS‐1 catalyst could expose Au nanoparticles on the external surface of TS‐1 and show high stability. The results provide direct evidence showing that micropore blocking is the deactivation mechanism. Based on the results, a simple strategy to design highly stable Au/Ti‐based catalysts is developed. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3963–3972, 2016     

Ethylene/1‐octadecene copolymerization using [η5:η1‐C5Me4‐4‐R1‐6‐R‐C6H2O]TiCl2 catalysts

Copolymerization of ethylene with 1‐octadecene was studied using [η⁵:η¹‐C₅Me₄‐4‐R₁‐6‐R‐C₆H₂O]TiCl₂ [R₁ = ^tBu (1), H (2, 3, 4); R = ^tBu (1, 2), Me (3), Ph (4)] as catalysts in the presence of Al(i‐Bu)₃ and [Ph₃C][B(C₆F₅)₄]. The effect of the concentration of comonomer in the feed and Al/Ti molar ratio on the catalytic activity and molecular weight of the resultant copolymer were investigated. The substituents on the phenyl ring of the ligand affect considerably both the catalytic activity and comonomer incorporation. The 1 /Al(i‐Bu)₃/[Ph₃C][B(C₆F₅)₄] catalyst system exhibits the highest catalytic activity and produces copolymers with the highest molecular weight, while the 2 /Al(i‐Bu)₃/[Ph₃C][B(C₆F₅)₄] catalyst system gives copolymers with the highest comonomer incorporation under similar conditions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of high molecular weight polyoxyethylene with a quaternary catalyst and study of its conductive blends with poly(2‐vinyl pyridine)

High molecular weight polyoxyethylene (PEO) was synthesized by using a quaternary catalyst composed of triisobutyl aluminum, phosphoric acid, water, and N,N‐dimethylaniline (DMA). Optimum synthesis conditions and some properties of the product were studied. This catalyst showed high activity and the molecular weight of the polyoxyethylene obtained can approach one million. The activity of polymerization mainly depends upon the composition of catalyst. The optimum composition is as follows: i‐Bu₃Al:H₃PO₄:H₂O:DMA = 1 : 0.17 : 0.17 : 0.10–0.15 (molar ratio).The active centers of the catalyst was thus proposed. The high molecular weight PEO synthesized by this catalyst was blended with poly(2‐vinyl pyridine) (PVP) and then doped with LiClO₄ and TCNQ to obtain a conductive elastomeric material. Ionic, electronic, and mixed (ionic–electronic) conductivities of blends were investigated. At a Li/EO molar ratio of 0.1 and a TCNQ/VP molar ratio of 0.5, the mixed conductivity of the blend of PEO/PVP/LiCIO₄/TCNQ is higher than the sum of ionic conductivity of PEO/PVP/LiCIO₄ and electronic conductivity of PEO/PVP/TCNQ, when the weight ratio of PEO to PVP is 6/4 or 5/5. It can reach 4 × 10^?6 S/cm at room temperature. Differential scanning calorimetry, thermal gravimetric analysis, and the appearance of the blend showed that both TCNQ and LiClO₄ can complex with PEO and PVP, thus enhancing the compatibility between PEO and PVP. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Influence of the synthesis conditions on the structural and thermal properties of poly(l‐lactide)‐b‐poly(ethylene glycol)‐b‐poly(l‐lactide)

The poly(l ‐lactide)‐b‐poly(ethylene glycol)‐b‐poly(l ‐lactide) block copolymers (PLLA‐b‐PEG‐b‐PLLA) were synthesized in a toluene solution by the ring‐opening polymerization of 3,6‐dimethyl‐1,4‐dioxan‐2,5‐dione (LLA) with PEG as a macroinitiator or by transterification from the homopolymers [polylactide and PEG]. Two polymerization conditions were adopted: method A, which used an equimolar catalyst/initiator molar ratio (1–5 wt %), and method B, which used a catalyst content commonly reported in the literature (<0.05 wt %). Method A was more efficient in producing copolymers with a higher yield and monomer conversion, whereas method B resulted in a mixture of the copolymer and homopolymers. The copolymers achieved high molar masses and even presenting similar global compositions, the molar mass distribution and thermal properties depends on the polymerization method. For instance, the suppression of the PEG block crystallization was more noticeable for copolymer A. An experimental design was used to qualify the influence of the catalyst and homopolymer amounts on the transreactions. The catalyst concentration was shown to be the most important factor. Therefore, the effectiveness of method A to produce copolymers was partly due to the transreactions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40419.     

Organosoluble and light‐colored fluorinated polyimides based on 1,1‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]‐1‐phenylethane and various aromatic dianhydrides

To investigate the CF₃ group affecting the coloration and solubility of polyimides (PI), a novel fluorinated diamine 1,1‐bis[4‐(4‐amino‐2‐ trifluoromethylphenoxy)phenyl]‐1‐phenylethane (2) was prepared from 1,1‐ bis(4‐hydrophenyl)‐1‐phenylethan and 2‐chloro‐5‐nitrobenzotrifluoride. A series of light‐colored and soluble PI 5 were synthesized from 2 and various aromatic dianhydrides 3a–f using a standard two‐stage process with thermal 5a– f(H) and chemical 5a–f(C) imidization of poly(amic acid). The 5 series had inherent viscosities ranging from 0.55 to 0.98 dL/g. Most of 5a–f(H) were soluble in amide‐type solvents, such as N‐methyl‐2‐pyrrolidone (NMP), N,N‐ dimethylacetamide (DMAc), and N,N‐dimethylformamide (DMF), and even soluble in less polar solvents, such as m‐Cresol, Py, Dioxane, THF, and CH₂Cl₂, and the 5(C) series was soluble in all solvents. The GPC data of the 5a–f(C) indicated that the Mn and Mw values were in the range of 5.5–8.7 × 10⁴ and 8.5–10.6 × 10⁴, respectively, and the polydispersity index (PDI) Mw /Mn values were 1.2–1.5. The PI 5 series had excellent mechanical properties. The glass transition temperatures of the 5 series were in the range of 232–276°C, and the 10% weight loss temperatures were at 505–548 °C in nitrogen and 508–532 °C in air, respectively. They left more than 56% char yield at 800°C in nitrogen. These films had cutoff wavelengths between 356.5–411.5 nm, the b* values ranged from 5.0–71.1, the dielectric constants, were 3.11–3.43 (1MHz) and the moisture absorptions were in the range of 011–0.40%. Comparing 5 containing the analogous PI 6 series based on 1,1‐bis[4‐(4‐aminophenoxy)phenyl]‐1‐ phenylethane (BAPPE), the 5 series with the CF₃ group showed lower color intensity, dielectric constants, and better solubility. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2399–2412, 2005     

Olefin production by cofeeding methanol and n‐butane: Kinetic modeling considering the deactivation of HZSM‐5 zeolite

The joint transformation of methanol and n‐butane fed into a fixed‐bed reactor on a HZSM‐5 zeolite catalyst has been studied under energy neutral conditions (methanol/n‐butane molar ratio of 3/1). The kinetic scheme of lumps proposed integrates the reaction steps corresponding to the individual reactions (cracking of n‐butane and MTO process at high‐temperature) and takes into account the synergies between the steps of both reactions. The deactivation by coke deposition has been quantified by an expression dependent on the concentration of the components in the reaction medium, which is evidence that oxygenates are the main coke precursors. The concentration of the components in the reaction medium (methanol, dimethyl ether, n‐butane, C₂? C₄ paraffins, C₂? C₄ olefins, C₅? C₁₀ lump, and methane) is satisfactorily calculated in a wide range of conditions (between 400 and 550°C, up to 9.5 (g of catalyst) h (mol CH₂)^?1 and with a time on stream of 5 h) by combining the equation of deactivation with the kinetic model of the main integrated process. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

Biodiesel Synthesis from Styrax confusus Hemsl Catalyzed by S2O82−/ZrO2‐TiO2‐Fe3O4

Biodiesel has been identified as a suitable resource that can be produced from biomass such as Styrax confusus Hemsl. In the current study, biodiesel was synthesized from Styrax confusus Hemsl oil catalyzed by a magnetic solid acid heterogeneous catalyst S₂O₈^2?/ZrO₂‐TiO₂‐Fe₃O₄, which had a high recovery rate and reusability. The catalyst was prepared by co‐precipitation and characterized by Fourier transform infrared spectroscopy, X‐ray diffraction and Brunauer, Emmett and Teller (BET) adsorption. The properties of the catalyst, including the recovery rate, usage count, magnetic susceptibility and catalytic efficiency, were studied. The results showed that the catalyst has a BET pore diameter of 1.74 nm, BET area of 7.3 m²/g, molar magnetic susceptibility of 1.83 × 10^?5 m³/kg and tetragonal structure. In addition, the influences of reaction conditions on yields of biodiesel were also discussed. A fatty acid methyl ester (FAME) yield of 90.02 % was obtained under the conditions of reaction time 1.5 h, reaction temperature 373 K, catalyst amount 5 %, and methanol‐to‐oil molar ratio 8:1. A FAME yield of 65.5 % was obtained when the catalyst was used for the fourth time.     

Kinetics of hydrogenation of 4‐chloro‐2‐nitrophenol catalyzed by Pt/carbon catalyst

Hydrogenation of 4‐chloro‐2‐nitrophenol (CNP) was carried out at moderate hydrogen pressures, 7–28 atm, and temperatures in the range 298–313 K using Pt/carbon and Pd/γ‐Al₂O₃ as catalysts in a stirred pressure reactor. Hydrogenation of CNP under the above conditions gave 4‐chloro‐2‐aminophenol (CAP). Dechlorination to form 2‐aminophenol and 2‐nitrophenol is observed when hydrogenation of CNP is carried out above 338 K, particularly with Pd/γ‐Al₂O₃ catalyst. Among the catalysts tested, 1%Pt/C was found to be an effective catalyst for the hydrogenation of CNP to form CAP, exclusively. To confirm the absence of gas–liquid mass transfer effects on the reaction, the effect of stirring speed (200–1000 rpm) and catalyst loading (0.02–0.16 g) on the initial reaction rate at maximum temperature 310 K and substrate concentration (0.25 mole) were thoroughly studied. The kinetics of hydrogenation of CNP carried out using 1%Pt/C indicated that the initial rates of hydrogenation had first order dependence with respect to substrate, catalyst and hydrogen pressure in the range of concentrations varied. From the Arrhenius plot of ln rate vs 1000/T, an apparent activation energy of 22 kJ mol^?1 was estimated. © 2001 Society of Chemical Industry     

Structure–Activity Relationship of Tumor‐Selective 5‐Substituted 2‐Amino‐3‐carboxymethylthiophene Derivatives

Methyl‐2‐amino‐5‐[2‐(4‐methoxyphenethyl)]thiophene‐3‐carboxylate ( 8 c ) is the prototype of a well‐defined class of tumor‐selective agents. Compound 8 c preferentially inhibited the proliferation of a number of tumor cell lines including many human T‐lymphoma/leukemia cells, but also several prostate, renal, central nervous system and liver tumor cell types. Instead, a broad variety of other tumor cell lines including B‐lymphomas and HeLa cells were not affected. The tumor selectivity (TS; selectivity index or preferential suppression of CEM lymphoma (IC₅₀=0.90 μM ) versus HeLa tumor cell carcinoma (IC₅₀=39 μM )) amounted up to ～43 for 8 c . At higher concentrations, the compound proved cytotoxic rather than cytostatic. The antiproliferative potency and selectivity of 8 c could be preserved by replacing the ethyl linker between the 2‐amino‐3‐carboxymethylthiophene and the substituted aryl by a thioalkyl but not by an oxyalkyl nor an aminoalkyl. Among >50 novel 8 c derivatives, the 5‐(4‐ethyl‐ and 4‐isopropylarylmethylthio)thiophene analogues, methyl‐2‐amino‐5‐((4‐ethylphenylthio)methyl)thiophene‐3‐carboxylate ( 13 m ) and methyl‐2‐amino‐5‐((4‐isopropylphenylthio)methyl)thiophene‐3‐carboxylate ( 13 n ), were more potent (IC₅₀: 0.3–0.4 μM ) and selective (TS: 100–144) anti‐T‐lymphoma/leukemia agents than the prototype compound.     

Biodiesel from canola oil using a 1 : 1 molar mixture of methanol and ethanol

Canola oil was transesterified using a 1 : 1 molar mixture of methanol and ethanol (M/E) with potassium hydroxide (KOH) catalyst. The effects of catalyst concentration (0.5–1.5 wt‐%), molar ratio of M/E to canola oil (3 : 1 to 20 : 1) and reaction temperature (25–75 °C) on the percentage yield measured after 2.5 and 5.0 min were optimized using a central composite design. A maximum percentage yield of 98% was obtained for a catalyst concentration of 1.1 wt‐% and an M/E to canola oil molar ratio of 20 : 1 at 25 °C at 2.5 min, whereas a maximum percentage yield of 99% was obtained for a catalyst concentration of 1.15 wt‐% and all molar ratios of reactants at 25 °C at 5 min. Statistical analysis demonstrated that increasing catalyst concentration and molar ratio of reactants resulted in curvilinear and linear trends in percentage yield, both at 2.5 and 5 min. However, reaction temperature, which affected the percentage yield at 2.5 min linearly, was insignificant at 5 min. The resultant mixed methyl/ethyl canola esters exhibited enhanced low‐temperature performance and lubricity properties in comparison to neat canola oil methyl esters and also satisfied ASTM D6751 and EN 14214 standards with respect to oxidation stability, kinematic viscosity, and acid value.     

Synthesis of branched polyethylene by ethylene homopolymerization with a novel (α‐diimine)nickel complex in the presence of methylaluminoxane

Branched polyethylene (PE) was prepared with a novel (α‐diimine)nickel(II) complex of 2,3‐bis(2,6‐dimethylphenyl)‐butanediimine nickel dichloride {[2,6‐(CH₃)₂C₆H₃? N?C(CH₃)C(CH₃)?N? 2,6‐(CH₃)₂C₆H₃]NiCl₂} activated by methylaluminoxane in the presence of a single ethylene monomer. The influences of various polymerization conditions, including the temperature, Al/Ni molar ratio, Ni catalyst concentration, and time, on the catalytic activity, molecular weight, degree of branching, and branch length of PE were investigated. According to gel permeation chromatography, the weight‐average molecular weights of the polymers obtained ranged from 1.7 × 10⁵ to 6.0 × 10⁵, with narrow molecular weight distributions of 2.0–3.5. The degree of branching in the polymers rapidly increased with the polymerization temperature increasing; this led to highly crystalline to totally amorphous polymers, but it was independent of the Al/Ni molar ratio and catalyst concentration. At polymerization temperatures greater than 20°C, the resultant PE was confirmed by ¹³C‐NMR to contain significant amounts of not only methyl but also ethyl, propyl, butyl, amyl, and long branches (longer than six carbons). The formation of the branches could be illustrated by the chain walking mechanism, which controlled their specific spacing and conformational arrangements with one another. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1123–1132, 2002; DOI 10.1002/app.10398     

Galvanic deposition of silver on 80‐μm‐Cu‐fiber for gas‐phase oxidation of alcohols

Microstructured Ag‐based catalysts were developed by galvanically depositing Ag onto 80‐μm‐Cu‐fibers for the gas‐phase oxidation of alcohols. By taking advantages including large voidage, open porous structure and high heat/mass transfer, as‐made catalysts provided a nice combination of high activity/selectivity and enhanced heat transfer. The best catalyst was Ag‐10/80‐Cu‐fiber‐400 (Ag‐loading: 10 wt%; Cu‐fiber pretreated at 400 °C in air), being effective for oxidizing acyclic, benzylic and polynary alcohols. For benzyl alcohol, conversion of 94% was achieved with 99% selectivity to benzaldehyde at 300 °C using a high WHSV of 20 h^?1. Computational fluid dynamics (CFD) calculation and experimental result illustrated significant enhancement of the heat transfer. The temperature difference from reactor wall to central line was about 10–20 °C for the Ag‐10/80‐Cu‐fiber‐400, much lower than that of 100–110 °C for the Ag‐10‐Cu‐2/Al₂O₃ at equivalent conversion and selectivity. Synergistic interaction between Cu₂O and Ag was discussed, being assignable to the activity improvement. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1045–1053, 2014     

Melt polycondensation of L‐lactic acid catalyzed by 1,3‐dialkylimidazolium ionic liquids

BACKGROUND: In syntheses of biodegradable and bioresorbable polymers, efficient metal‐free catalysts are very desirable as the resulting products may be more biocompatible. As an attempt to find new metal‐free catalysts, 1,3‐dialkylimidazolium salts, the most commonly used ionic liquids or organic melt salts, were used as single‐component catalysts in the melt polycondensation of L ‐lactic acid for the first time. The resulting poly(L ‐lactic acid) (PLLA) was characterized using gel permeation chromatography, ¹³C NMR, DSC and polarimetry. RESULTS: It has been found that less bulky substituents on the imidazolium ring are conducive to catalytic activity. PLLA with molar mass of about 20 000 g mol^?1 was synthesized at high yield (over 70%) in the presence of various 1,3‐dialkylimidazolium salts. The product exhibits satisfactory color (white to slightly yellow), optical purity (89–95%) and crystallinity (40–55%). A possible catalytic mechanism is proposed. CONCLUSION: As compared with the well‐known binary catalyst system SnCl₂ · 2H₂O/toluene sulfonic acid, the catalysts used in this investigation are better in terms of increasing PLLA yield and preventing discoloration and comparable in terms of racemization. Copyright © 2008 Society of Chemical Industry     

Gas phase polymerization of 1,3‐butadiene with supported neodymium‐based catalyst: Investigation of molecular weight

The gas phase polymerization of 1,3‐butadiene (Bd), with supported catalyst Nd(naph)₃/Al₂Et₃Cl₃/Al(i‐Bu)₃ or/and Al(i‐Bu)₂H, was investigated. The polymerization of Bd with neodymium‐based catalysts yielded cis‐1,4 (97.2–98.9%) polybutadiene with controllable molecular weight (MW varying from 40 to 80 × 10⁴ g mol^?1). The effects of reaction temperature, reaction time, Nd(naph)₃/Al(i‐Bu)₃ molar ratio, and cocatalyst component on the catalytic activity and molecular weight of polymers were examined. It was found that there are two kinds of active sites in the catalyst system, which mainly influenced the MW and molecular weight distribution of polybutadiene. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1945–1949, 2004     

Synthesis of some new 2‐[(2,3‐dihydroinden‐1‐ylidene) hydrazinyl]‐4‐methylthiazole derivatives for simultaneous dyeing and finishing for UV protective cotton fabrics

Several 2‐[1‐(1,2‐dihydroinden‐3‐ylidene) hydrazono]‐5‐aryldiazo‐4‐methyl‐1,3‐thiazoles were synthesized by reaction of 1‐(1,2‐Dihydroinden‐3‐ylidene) thiosemicarbazide with different hydrazonyl chlorides. The products are water insoluble and UV absorbers, expressed UPF‐rating values, and their H₂O/DMF solutions were used in simultaneous dyeing and resin finishing of cotton fabrics. Results obtained show that finishing of cotton samples in presence of any of that dyes, irrespective of dye concentration, brings about an improvement in percent nitrogen, wrinkle recovery angle (WRA), dyeability, and UV protection rating values along with slight decrease of tensile strength (TS) compared with the untreated samples. Irrespective of dye structure, increasing the dye concentration from 0.5 and up to 1.7% results in an improvement in the percent nitrogen, TS and a remarkable improvement in both the dyeability, UPF‐rating values along with slight decrease in WRA and lower fastness properties of the treated fabrics. The treated fabrics was characterized using energy dispersive X‐ray analysis indicating the entrapped dye within the fabric structure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Polymerization of cyclic monomers. VII. Synthesis and radical polymerization of 1,3‐bis[(1‐alkoxycarbonyl‐2‐vinylcyclopropane‐1‐yl)carboxy]benzenes

1,3‐Bis[(1‐alkoxycarbonyl‐2‐vinylcyclopropane‐1‐yl)carboxy]benzenes 1 [RO: CH₃O (a), C₂H₅O (b)] were synthesized by the esterification of the corresponding 1‐alkoxycarbonyl‐2‐vinylcyclopropane‐1‐carboxylic acids with resorcinol. The structure of the new vinylcyclopropanes was confirmed by elemental analysis and infrared (IR), ¹H nuclear magnetic resonance (¹H‐NMR), and ¹³C nuclear magnetic resonance (¹³C‐NMR) spectroscopy. The radical polymerization of difunctional 2‐vinyl‐cyclopropanes in bulk with 2,2′‐azoisobutyronitrile (AIBN) results in hard, transparent, crosslinked polymers. During the bulk polymerization of the crystalline bis[(1‐methoxycarbonyl‐2‐vinylcyclopropane‐1‐yl)carboxy]benzene 1a, an expansion in volume of about 1% took place. The radical solution polymerization of 1a resulted in a soluble polymer with pendant 2‐vinylcyclopropane groups. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1775–1782, 1999     

Novel Co‐Mn‐O nanosheet catalyst for CO preferential oxidation toward hydrogen purification

Co‐Mn‐O composite oxide nanosheet catalyst was successfully prepared using a facile urea‐assisted one‐step hydrothermal method in the absence of organic or organic templating reagent. Co‐Mn‐O nanosheet catalyst was optimized by varying hydrothermal process parameters such as molar ratio of Co‐Mn to urea, hydrothermal temperature, and hydrothermal time. Various characterization techniques including scanning electron microscopy, X‐ray diffraction, nitrogen adsorption, X‐ray photoelectron spectroscopy, Raman spectroscopy, and H₂ temperature‐programmed reduction were used to reveal the relationship between catalyst nature and catalytic performance in CO preferential oxidation (CO PROX) in excess H₂. The developed Co‐Mn‐O nanosheet catalyst have demonstrated much superior catalytic performance to Co‐Mn‐O nanoparticle, particularly in the low temperature range, and 100% CO conversion over the developed Co‐Mn‐O nanosheet can be achieved in temperature range of 50 to 150°C at 10,000 mL g^?1 h^?1 of gas hourly space velocity in the standard feed. Furthermore, the almost complete CO removal over Co‐Mn‐O nanosheet at 125°C of low temperature with 94.9% selectivity can be achieved even in the simulated reformed gas. The excellent catalytic performance is ascribed to nanosheet morphology, more surface Co³⁺, smaller average crystallite size, higher reducibility, and strong Co‐Mn interaction. Catalytic stability investigation indicates the developed nanostructured catalyst exhibits high catalytic stability for CO PROX reaction in simulated gas. The developed Co‐Mn‐O nanosheet catalyst can be a potential candidate for catalytic elimination of trace CO from H₂‐rich gas for Proton exchange membrane fuel cell applications. © 2014 American Institute of Chemical Engineers AIChE J, 61: 239–252, 2015     

Reaction between methanol and acetic acid catalyzed by SiO2‐supported V‐P‐O catalyst in oxygen atmosphere

SiO₂‐supported V‐P‐O catalysts prepared by the incipient‐wetness impregnation method beginning with ammonium metavanadate and phosphoric acid were used in the catalytic reaction between methanol and acetic acid in an oxygen atmosphere. The SiO₂‐supported V‐P‐O catalysts were composed of VOPO₄ and (VO)₂P₂O₇ phases. Both the acidic and alkaline sites were co‐present in the catalysts. The vanadium species catalyzed the oxidation of methanol to formaldehyde. The V‐P‐O(20–30 wt%)/SiO₂ catalysts with a P/V mole ratio of 2:1 exhibited higher catalytic activity for the formation of acrylic acid and methyl acrylate with a total selectivity of ～28 % at 380 °C. The acid sites of the catalysts also catalyzed the formation of methyl acetate with a selectivity of ～65 %. Methanol can be an alternative to formaldehyde for the synthesis of both acrylic acid and methyl acrylate through the aldol condensation reaction.     

Production of bio‐crude from forestry waste by hydro‐liquefaction in sub‐/super‐critical methanol

Hydro‐liquefaction of a woody biomass (birch powder) in sub‐/super‐critical methanol without and with catalysts was investigated with an autoclave reactor at temperatures of 473–673 K and an initial pressure of hydrogen varying from 2.0 to 10.0 MPa. The liquid products were separated into water soluble oil and heavy oil (as bio‐crude) by extraction with water and acetone. Without catalyst, the yields of heavy oil and water soluble oil were in the ranges of 2.4–25.5 wt % and 1.2–17.0 wt %, respectively, depending strongly on reaction temperature, reaction time, and initial pressure of hydrogen. The optimum temperature for the production of heavy oil and water soluble oil was found to be at around 623 K, whereas a longer residence time and a lower initial H₂ pressure were found to be favorite conditions for the oil production. Addition of a basic catalyst, such as NaOH, K₂CO₃, and Rb₂CO₃, could significantly promote biomass conversion and increase yields of oily products in the treatments at temperatures less than 573 K. The yield of heavy oil attained about 30 wt % for the liquefaction operation in the presence of 5 wt % Rb₂CO₃ at 573 K and 2 MPa of H₂ for 60 min. The obtained heavy oil products consisted of a high concentration of phenol derivatives, esters, and benzene derivatives, and they also contained a higher concentration of carbon, a much lower concentration of oxygen, and a significantly increased heating value (>30 MJ/kg) when compared with the raw woody biomass. © 2009 American Institute of Chemical Engineers AIChE J, 2009