The Selective Reduction of 4-Propylthio-2-nitroaniline with CO Using Ru3（CO）12／PEDPA Complex as Catalyst

The Ru3(CO)12/PEDPA complex was firstly applied in the CO selective reduction of 4-propylthio-2-nitroaniline.The effects of reaction temperature,the pressure of CO and concentration of catalyst on the reduction were investigated.Under the optimum conditions of T=140℃, Pco=5.0MPa and substrate/catalyst=300(molar ratio),the conversion and selectivity were 70% and 98%,respectively.After simple phase separation,the catalyst could be recycled.     

锗钨酸催化合成水杨酸异戊酯

Isoamyl salicylate was synthesized by using germanotungtic acid as catalyst.The effects of the amaunt of catalyst,the molar ratio of salicycic acid of isoamy l alcohol,the reaction temperature and the reaction time on the yield of ester w ere studied.The optimum reaction conditions were 1.3∶100 (mass ratio) of cataly st to reactants,1∶2.5 (molar ratio) of acid to alcohol,135～153℃ being satisfa ctary reaction temperature and reaction time suitable being 3h.Under such condit ion,the yield of ester was up to 94%.Germanotungtic acid catalyst can be used re peatedly.     

THE EFFECT OF SENSITIZERS ON PARTIAL OXIDATION OF METHANE TO FORMALDEHYDE

Ketone was the optimum sensitizer selected from many additives. With ketonc as the additive, the yield of formaldehyde was more than 2.40% and the highest yield Was 3.58% over the silica gel-1 catalyst, and remained almost unchanged during the catalyst life test of 500 h. Ketone can compensate the catalyst for the -OH loss shown by 1R, TGA and XPS of the catalysts before and after the reaction.     

固体酸Fe2(SO4)3催化合成丙酸异戊酯

Solid acid ferric sulphate Fe2(SO4)3 was prepared and used for the study of the catalytic synthesis of iso-amyl propionate. The optimun reaction conditions were follows: the ratio of amount of substance n(iso-amylalcohol) : n(propionic acid) = 1.5, the reaction time 2h, the catalyst quantity 1.5g, and dewatering solvent toluene 10ml. The yield was 97.2% under the optimum reaction conditions. The catalyst being of high catalytic activity for the esterification reactions was prepared very easily and could be used repeatedly.     

Preparation, Characterization and Catalytic Performance of La-SO4/SBA-15 in Esterification of Acetic Acid with n-Butanol

La-SO42-/SBA-15 was synthesized with various amounts of lanthanum via incipient-wetness impregnation. Characterization was done by X-ray diffraction（XRD）, transmission electron micrographs（TEM）, nitrogen adsorption, FTIR spectroscopic analysis, thermogravimetric analysis, and the total amount of acidity of catalyst was estimated by TPD of NH3. The results indicate that lanthanum has been incorporated into SBA-15 molecular sieve. The prepared materials（La-SO42-/SBA-15） keep the highly ordered mesoporous two-dimensional hexagonal structure and do not change the mesoporous channel structure of the support SBA-15. The catalyst showed best catalytic activity in the synthesis of n-butyl acetate. The optimum conditions of the esterification by orthogonal experiments were studied： the molar ratio of n-butanol to acetic acid 1：1.2, the amount of catalyst 7.5%, reaction time 80 min. The yield of n-butyl acetate could reach 93.2% under the optimum conditions. The catalyst was recyclable, cost effective and environmental friendly.     

Ring-closing Metathesis on an Allyl-terminated Carbosilane Dendrimer

Grubbs‘ catalyst was used to prepare a series of carbosilane dendrimers with silacyclopentene peripheral groups. It was found that ring closing metathesis reaction was influenced strongly by the reaction temperature and the amount of catalyst.     

STUDY OF THE CATALYTIC TECHNOLOGY IN THE OXIDATIVE COUPLING OF METHANE

The temperature of the catalyst bed in the oxidative coupling ofmethane would rise and be higher than the wall temperature when the amountof catalyst, the space velocity and the ratio of oxygen to methane wereincreased. Various aspects of the catalytic technology including the thickness ofthe catalyst bed, the mode of catalyst charge, the ratio of CH_4 to O_2 and thespece velocity were studied. An optimum temperature of the catalyst bed forhigher methane conversion and C_2 selectivity was investigated. It was foundthat the burning of methane in the gas phase to form CO occurred at certaintemperatures with some ratios of oxygen to methane. Additionally, the effectof adding water to the reaction feed gas was studied.     

BiMo基复合氧化物催化剂丙烷直接氧化至丙烯醛研究

The effects of the available zoon above the catalyst bed on the performance of the catalyst were investigated. It has been suggested that propylene is an intermediate species in the reaction of propane to acrolein， and a two-step reaction scheme is proposed， the first step is oxidative dehydrogenation of propane to propylene in the gas phase then followed by the second step， the selective oxidation of propylene to acrolein on the surface of the catalyst. The performance of the catalyst depends on both the oxidative dehydrogenation of propane to propylene in the gas phase and the selective oxidation of propylene to acrolein on the catalyst surface. The thermal cracking， homogeneous oxidative dehydrogenation and heterogeneous catalytic dehydrogenation of propane as well as the selective catalytic oxidation of propane to acrolein over BiMoO based mixed oxides catalysts were studied. Under the optimum reaction conditions of propane dehydrogenation and selective oxidation of propylene， the selectivity and the yield of acrolein approached to 45mol% and 14mol%， respectively under about 30mol% propane conversion.     

Effects of preparation and operation conditions on precipitated iron nickel catalysts for Fischer-Tropsch synthesis

Iron nickel oxide catalysts were prepared using co-precipitation procedure and studied for the conversion of synthesis gas to light olefins. In particular, the effects of a range of preparation variables such as [Fe]/[Ni] molar ratios of the precipitation solution, precipitate aging times, calcination conditions, different supports and loading of optimum support on the structure of catalysts and their catalytic performance for the tested reaction were investigated. It was found that the catalyst containing 40%Fe/60%Ni/40wt%Al2O3, which was aged for 180 min and calcined at 600 ℃ for 6 h was the optimum modified catalyst. The catalytic performance of optimal catalyst has been studied in different operation conditions such as reaction temperatures, H2/CO molar feed ratios and reaction total pressure. Characterization of both precursors and calcined catalysts was carried out by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area measurements, thermal analysis methods such as thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC).     

Stability improvement of the Nieuwland catalyst in the dimerization of acetylene to monovinylacetylene

In the process of dimerization of acetylene to produce monovinylacetylene (MVA),the loss of active component CuCl in the Nieuwland catalyst due to the formation of a dark red precipitate was investigated.The formula of the precipitate was CuCl·2C2H2·1/5NH 3,and it was presumed to be formed by the combination of NH 3,C2H2 and [Cu]-acetylene π-complex,which was an intermediate in the dimerization reaction.The addition of hydrochloric acid into the catalyst can reduce the formation of precipitate,whereas excessive H+ is unfavorable to the dimerization reaction of acetylene.To balance between high acetylene conversion and low loss rate of CuCl,the optimum mass percentage of HCl in the added hydrochloric acid was determined.The result showed the optimum mass percentage of HCl decreased from 5.0% to 3.2% when the space velocity of acetylene was from 140 h-1 to 360 h-1.The result in this work also indicated the pH of the Nieuwland catalyst should be kept in the range of 5.80-5.97 during the reaction process,which was good for both catalyst life and acetylene conversion.     

Studies on Tripolycyanamide Formaldehyde Resin-Pd Complex and Its Use in the Synthesis of the Branch of Paclitaxel

A novel method was developed to prepare the branch of paclitaxel using 2,4-dichlorophenylaldehyde as the starting material.The branch was synthesized through condensation, cydoaddltion and catalyzing hydrogenation of dichlorophenyl intermediate. Tripolycyanamide formaldehyde resin-Pd complex as hydrogenation catalyst has been studied. The influence of temperature and N/Pd atomic ratio of the catalyst on the effect of catalytic hydrogenation was investigated and the optimum conditious were found. Because of the mild cyclization reaction condition, convenient asymmetric resolution operation and high yield, the synthetic route was practical.     

Optimization and statistical analysis of Au-ZnO/Al2O3 catalyst for CO oxidation

In our former work[Catal.Today 174（2011） 127],12 heterogeneous catalysts were screened for CO oxidation,and Au-ZnO/Al₂O₃ was chosen and optimized in terms of weight loadings of Au and ZnO.The present study follows on to consider the impact of process parameters （catalyst preparation and reaction conditions）,in conjunction with catalyst composition（weight loadings of Au and ZnO,and the total weight of the catalyst）,as the optimization of the process parameters simultaneously optimized the catalyst composition.The optimization target is the reactivity of this important reaction.These factors were first optimized using response surface methodology（RSM） with 25 experiments,to obtain the optimum:100 mg of 1.0%Au-4.1%ZnO/Al₂O₃ catalyst with 220℃calcination and 100℃reduction.After optimization,the main effects and interactions of these five factors were studied using statistical sensitivity analysis（SA）.Certain observations from S A were verified by reaction mechanism,reactivity test and/or characterization techniques,while others need further investigation.     

Synthesis of glycerin triacetate over molding zirconia-loaded sulfuric acid catalyst

Zirconia-loaded sulfuric acid (SO24- /ZrO2) catalysts were prepared by impregnation method, molded by punch tablet machine and characterized by X-ray diffraction. SO42- /ZrO2 catalyst was used to obtain glycerol triacetate (GTA) directly from glycerin. The effect of some factors, such as different temperatures of calcination and catalysts molded or not, on the reusable times of catalysts and the yield of GTA were investigated. The optimum reaction conditions were shown as follows: the reaction temperature was 403 K; the reaction time continued for 8 h; the amount of molded catalysts was 5 wt% of glycerin and the molar ratio of glycerin to acetic acid was 1 : 8. The yield of GTA was 97.93% under the optimum condition.     

SYNTHESIS OF ALCOHOLS FROM HYDROGENATION OF CARBON DIOXIDE(Ⅲ)

The effects of catalyst preparation and reaction conditions on thecatalytic activity and selectivity for hydrogenation of carbon dioxide to alcoholsover zeolite supported bimetal catalyst were studied.The results showed that:(1)ethanol easily formed on the zeolite with larger pores and methanol did onthat with smaller pores;(2)when pH value of the ion exchange solution was10,the activity reached the maximum;(3)the optimum Cu/Ru mole ratio was3;(4)the influence of reation conditions such as temperature,pressure andH_2/CO_2 mole ratio on the topic reaction was greater.     

Novel,efficient,and green procedure for the synthesis of 1,5-benzodiazepines catalyzed by MgBr_2 in aqueous media

MgBr_2 performs as a novel catalyst for the synthesis of various 1,5-benzodiazepine derivatives from wide range of substituted ophenylenediamines and various ketones in good to excellent isolated yields(93-98%)using water as solvent at ambient temperature.Several solvents were examined for this reaction;however,in terms of reaction yield and time,water was found to be the optimum solvent.The remarkable advantages offered by this method are easily and inexpensive available catalyst,simple procedure,mild c...     

Alkali salts of heteropoly tungstates: Efficient catalysts for the synthesis of biodiesel from edible and non-edible oils

Alkali salts of tungsten based heteropoly acids with different central atom such as P, Si and Co were prepared and evaluated for transesterification of both edible and non-edible oils to their corresponding fatty acid methyl esters. The catalyst of sodium salt of tungstic acid with Co as central atom(Na5Co W12O40) showed optimum activity towards transesterification compared with other heteropoly tungstates.The catalysts activities were correlated with the observed physico-chemical characteristics derived from FT-infrared(FT-IR), X-ray diffraction(XRD), temperature-programmed desorption of ammonia(NH3-TPD) and carbon dioxide(CO2-TPD). The Na5 Co W12O40catalyst exhibiting high activity even at 65°C is due to the presence of strong acidic as well as basic sites. The disclosed catalyst is tolerable towards water and free fatty acids present in the oils. The influence of catalyst loading, reaction time and reaction temperature is studied to optimize the reaction parameters.     

Study on the Synthesis of Phenylacetic Acid by Carbonylation of Benzyl Chloride under Normal Pressure

The influences of some factors on the yield of phenylacetic acid in the carbonylation of benzyl chloride were studied in this paper. These factors included the variety and content of catalyst, and that of solvent, way of material feeding, reaction temperature, sodium hydrate concentration, triphenylphosphine content, presence of surfactant, the ratio of organic phase volume to aqueous phase volume etc. The optimum reaction conditions were found to be: with a one-time pour of 0.15g Pd(PPh3)2Cl2, 0.24g PPh3, 75ml NaOH of 3.5mol/L, 20ml benzyl chloride and 55ml n-butyl alcohol, and the reaction was carried out at 50℃ for about 3 hours. The as-obtained yield of phenylacetic acid was as high as 97.6%. In addition, the influences of the presence of phenylacetic acid and air in the reaction system were also studied. The results showed that the presence of air in the system and the entrainment of phenylacetic acid in the circulating organic phase had great influence on the reaction rate, the stability and performance of catalyst and the yield of phenylacetic acid.     

Scale Inhibition of Green Inhibitor Polyepoxysuccinic Sodium

Polyepoxysuccinic acid (PESA) is the green water treatment agents recognized all over the world[1-3]. It is found that when PESA is used alone, it had good scale inhibition. PESA should be included in the category of green scale inhibitor. PESA is synthesized with maleicanhydride in the presence of catalysts. The effect on scale-in-hibiting property of the product from amount and feed times of catalyst, the reaction temperature, the reaction time were investigated. The optimum reaction c…     

EFFECT OF PREPARATION OF SUPPORTED Mo-CATALYST ON THE ADSORPTION AND SURFACE REACTION RATE COEFFICIENTS

The effects of preparative variables of the supported Mo catalyst on the properties of adsorp-tion and reaction were studied by the CRCT at 250-290°C under atmospheric pressure.The resultsshow that the Mo content and sulphurization temperature mainly affect the number of adsorption sitesof thiophene and the match of adsorbed thiophene and hydrogen.The calcination temperature influencesnot only the numbers and nature of adsorption sites of thiophene but also the turn-over frequency ofsurface reaction of adsorbed thiophene,which increases largely with calcination temperature,becausethe interaction of metal-support is stronger at higher calcination temperature.The results also show thatthe Mo content of monolayer capacity,sulphurization at 400°C and calcination at 500°C would lead toan optimum match of adsorbed thiophene and hydrogen,i.e.the highest reaction rate and the lowestactivation energy of reaction would be obtained under these treatment conditions.     

Study on Ni/C catalysts for vapor phase carbonylation of ethanol

Activated carbon-supported Ni catalysts for vapor phase carbonylation of ethanol to propionic acid in the presence of ethyl iodide as promoter were investigated. Under optimum reaction conditions, the conversions of carbon monoxide and ethanol were measured to be 81.4% and 98.4%, respectively, while the selectivity for propionic acid was found to be 98.65%. The catalyst was stable within 48 h on stream. XRD and XPS methods were used to characterize the structures and surface properties of the fresh and tested catalysts. The characterization results indicated that aggregation of nickel particles and formation of nickel iodide on the catalyst surface should be responsible for the deactivation of the catalysts.