Reverse Microemulsion Synthesis and Characterization of Pd-Ag Bimetallic Alloy Catalysts Supported on Al2O3 for Acetylene Hydrogenation

Pd-Ag bimetallic alloy nanoparticles were synthesized by the reverse microemulsion method,and then deposited on Al2O3 to form the supported catalyst.The nanoparticles of Pd-Ag and Pd-Ag/Al2O3 samples were characterized by UV/Vis,HRTEM,EDX,XRD,and XPS.The test results indicated that Pd-Ag bimetallic alloy nanoparticles with a size of about 2 nm and a face-centered cubic(fcc) structure were formed in the measured area of microemulsion.The growth of nanoparticles was effectively limited within the droplet of micoremulsion.TEM image exhibited that the Pd-Ag alloy nanoparticles were well-dispersed on the Al2O3 support.The catalytic performance of various catalysts for selective hydrogenation of acetylene showed that a higher acetylene conversion and selectivity to ethylene upon acetylene hydrogenation was achieved on a nano-sized Pd-Ag bimetallic catalyst with a Pd/Ag alloy supported molar ratio of 1:1.5.     

正庚烷催化裂解生产低碳烯烃的影响因素探索

The influence of zeolite structure and process parameters (including reaction temperature and catalyst/oil ratio) on rules for formation of ethylene and propylene in the course of catalytic pyrolysis of n-heptane was studied in a small- scale fixed fluid catalytic cracking unit. Test results have revealed that compared to the USY zeolite and Beta zeolite, the catalytic pyrolysis of n-heptane in the presence of the ZRP zeolite catalyst can result in higher yield and selectivity of ethyl- ene and propylene, while a higher reaction temperature and a higher catalyst/oil ratio can promote the formation of ethylene and propylene during catalytic pyrolysis of n-heptane. The ethylene formation reaction is more sensitive to the changes in reaction temperature, whereas the changes in catalyst/oil ratio are more influential to the propylene formation reaction. This paper has made a preliminary exploration into the different reaction pathways for formation of ethylene and propylene on zeolites with different structures.     

Reactive Adsorption of Thiophene Using a NiZnO-Based Adsorbent

The thiophene removal ability of the synthesized NiZnO-based adsorbent was tested in a lab-scale fixed-bed system. The X-ray diffractometer (XRD) and the temperature-programmed reduction (H2-TPR) instrument were used to characterize the samples. The XRD and TPR results showed that there existed stronger synergetic effect between ZnO and NiO to form well-dispersed adsorbent particles when the Zn/Ni molar ratio in adsorbent was 0.4, and that the optimum temperature for reduction of the NiZnO-based adsorbent was approximately in the range of 350℃—400℃. In addition, the effects of reaction temperature, and reaction pressure on the reactive adsorption desulfurization tests were studied.     

盐酸三乙胺-三氯化铝离子液体催化甲苯与氯代叔丁烷烷基化反应

Alkylation of toluene with 2-chloro-2-methylpropane (t-Bu-Cl) to synthesize para-tert-butyltoluene (PTBT) was carried out in the presence of triethylamine hydrochloride-aluminum chloride ionic liquids used as the catalyst. The ionic liquids were prepared with different molar ratios of Et3NHCl to AlCl3 , and the effect of the molar ratio between AlCl 3 and Et3NHCl, the reaction time, the reaction temperature, the ionic liquid dosage, as well as the molar ratio of toluene to chloro-2-methylpropane on the alkylation reaction of toluene with chloro-2-methyl-propane was investigated. The test results showed that the acidic ionic liquids prepared with Et3NHCl and AlCl3 had good activity and selectivity for the alkylation reaction of toluene with alkyl chloride to produce PTBT. The optimal reaction conditions were specified at anAlCl3 to Et3NHCl ratio of 1.6, a reaction temperature of 20℃, a mass fraction of toluene to ionic liquid of 10%, and a chloro-2-methylpropane to toluene molar ratio of 0.5. Under the suitable reaction conditions, a 98% conversion of chloro-2-methylpropane and an 82.5% selectivity of PTBT were obtained. Ionic liquids could be reused 5 times with its catalytic activity unchanged, and the regenerated ionic liquids can be recycled.     

SiW/Hβ催化剂用于挂式四氢双环戊二烯的制备

Exo-tetrahydrodicyclopentadiene (exo-TCD) is an important high-energy fuel.Silicotungstic acid (SiW) immobilized on H-type β zeolite (Hβ) at room temperature were used to prepare the Hβ zeolite catalysts with different SiW contents.Catalytic performances of the catalysts were investigated during the preparation of exo-TCD via isomerization of endo-tetrahydrodicyclopentadiene (endo-TCD).The properties of catalysts were characterized by XRD,temperature pro-grammed desorption of ammonia (NH 3-TPD),FT-IR,and N 2-adsorption techniques.SiW was highly dispersed on the surface of Hβ zeolite,and the 10% SiW/Hβ zeolite catalyst had the highest amount of weak acidity among all SiW/Hβ zeolite catalysts.The influence of different factors on isomerization reaction was investigated.At a reaction temperature of 240 ℃,a n(cyclohexane) /n(endo-TCD) ratio of 10,a m(catalyst) /m(endo-TCD) ratio of 0.3,an initial pressure of 1.0 MPa,and a reaction time of 1.5 h in the presence of 10% SiW/Hβ catalyst calcined at 400 ℃,the conversion of endo-TCD reached up to 92.0%,with the yield of exo-TCD equating to 51.0%.     

Transesterification Reaction of Waste Cooking Oil and Chicken Fat by Homogeneous Catalysis

In the last years, biodiesel production has been on a steady increase due to it is renewable and biodegradable fuel. The process to obtain biodiesel can be carried out using different raw materials. It is conlmonly performed by transesterification reaction of vegetable oils with methanol and using a homogeneous or heterogeneous catalyst. This work seeks to compare the results produced in transesterification of wasted cooking oil and chicken fat by homogeneous catalysis with NaOH. Due to in each case triglyceride comes from different raw materials, operation conditions differ slightly, which is more evident in the values used for the temperature. For chicken fat was used temperature variations between 35 ℃ and 55 ℃, varying catalyst in percentages between 0.3% and 0.7% with a molar ratio 6：1 in all cases and a reaction time of I h. Likewise, the conditions used in the tmnsesterification process of waste cooking oil were temperature between 50 ℃ and 60 ℃ with a molar ratio 6/1 and 9/1 for alcohol and oil, and catalyst percentage between 0.5% and 0.7% by weight. The yields obtained were between 78% and 94%, or 83% and 95%, for chicken fat and wasted cooking oil, respectively.     

Synthesis of Methyl 3-Hydroxypropanoate by Hydroesterification of Ethylene Oxide over Dicobalt Octacarbonyl Catalyst

Methyl 3-hydroxypropanoate was synthesized via hydroesterification of ethylene oxide with CO in the presence of dicobalt octacarbonyl catalyst and methanol solvent. The catalyst exhibited high catalytic activity. The effect of reaction temperature, CO pressure, methanol dosage, catalyst dosage and reaction time on catalytic reaction was investigated. The test results revealed that this reaction was greatly affected by reaction temperature, but it was not significantly affected by the CO pressure, the methanol dosage, the catalyst dosage and the reaction time. Under the optimal conditions, the conversion of ethylene oxide was equal to 92.24%, while the selectivity and yield of methyl 3-hydroxypropanoate reached 88.99% and 84.35%, respectively.     

Macrokinetics of Ethylene Epoxidation over A-type Silver Catalyst

By taking the surface chemical reactions as the rate-controlling step, a possible reaction mechanism for ethylene epoxidation to synthesize ethylene oxide over the A-type silver catalyst was developed, while it was assumed that the epoxidation reaction would take place between ethylene and the un-dissociated adsorbed oxygen O2 a on the solo active sites, while the deep oxidation would occur between ethylene and the dissociated adsorbed oxygen Oa on the adjacent multi-active sites. In order to describe the effect of 1,2-C2H4Cl2(EDC) inhibitor on the ethylene epoxidation process, the reversible reactions between EDC and vinyl chloride(VC) on the active sites of silver catalyst was introduced. According to the assumed mechanism, the hyperbolic macro-kinetic model of ethylene epoxidation over the A-type silver catalyst was established, and the macrokinetic experiments were carried out in an internal-recycle gradientless reactor operating at a pressure of 2.1 MPa and a temperature in the range of 217.8—249.0 ℃, with the gas composition(molar fraction) consisting of 15.82%—34.65% C2H4, 2.55%—7.80% O2, 0.88%—6.15% CO2, 0.15—2.61 μmol/mol of 1,2-C2H4Cl2 and 0.14—1.28 μmol/mol of C2H3 Cl. By means of the Simplex Optimal Method, the parameters of the macrokinetic models were estimated. Statistical test showed that the macrokinetic models developed for the A-type silver catalyst agree well with the experimental results.     

Extractive oxidative desulfurization of model oil/crude oil using KSF montmorillonite-supported 12-tungstophosphoric acid

12-Tungstophosphoric acid(PW) supported on KSF montmorillonite, PW/KSF, was used as catalyst for deep oxidative desulfurization(ODS) of mixed thiophenic compounds in model oil and crude oil under mild conditions using hydrogen peroxide(H_2O_2) as an oxidizing agent. A one-factor-at-a-time method was applied for optimizing the parameters such as temperature, reaction time, amount of catalyst, type of extractant and oxidant-tosulfur compounds(S-compounds) molar ratio. The corresponding products can be easily removed from the model oil by using ethanol as the best extractant. The results showed high catalytic activity of PW/KSF in the oxidative removal of dibenzothiophene(DBT) and mixed thiophenic model oil under atmospheric pressure at 75 ℃ in a biphasic system. To investigate the oxidation and adsorption effects of crude oil composition on ODS, the effects of cyclohexene, 1,7-octadiene and o-xylene with different concentrations were studied.     

Studies on the Reaction Mechanism of CPP and the Factors Affecting the Yields of Ethylene and Propylene

The reaction mechanisms of Catalytic Pyrolysis Process and the ethylene and propylene forma-tion reaction are analyzed,and ethylene and propylene are produced through both the free radical reac-tion and carbenium ion reaction.The factors affecting the yields of ethylene and propylene are discussed.The results showed that greater yields of ethylene and propylene can be obtained on ZSM-5 catalysts rather than USY and REY catalysts,and the modified ZSM-5 could improve the ethylene yield.A higher temperature is favorable for enhancement of the free radical reaction as opposed to carbenium ion reaction,and change in temperature can adjust the ratio of ethylene and propylene production.A higher steam amount could produce more ethylene and propylene and less coke,and lowering the catalyst/oil ratio is favorable for producing ethylene.     

Residue Upgrading in Slurry Phase over Ultra-fine NiMo/γ-Al_2O_3 Catalyst

In this article, residual oil hydroconversion was studied in slurry phase in the presence of fine solid Ni Mo/γ-Al2O3 catalyst and the effects of operating conditions were carefully studied. The results showed that residue conversion was only affected by the reaction temperature and reaction time. The coke yield increased with a higher reaction temperature, a bigger catalyst particle size, a longer reaction time, a lower initial hydrogen pressure and a lower catalyst concentration. Heteroatoms removal rate increased with a higher reaction temperature, a longer reaction time, a higher initial hydrogen pressure, a higher catalyst concentration, and a smaller catalyst particle size. The role of catalyst in the slurry bed technology was discussed and its function could be stated as follows: the metal was applied to activate the hydrogen atoms for removing heteroatoms and saturating aromatics, while the support of the catalyst was used to prevent the mesophase coalescence for reducing coke formation.     

Research on Ethylene and Propylene Formation during Catalytic Pyrolysis of Methylcyclohexane

The influence of operating parameters and type of zeolite catalysts on formation of ethylene and propylene during catalytic pyrolysis of methylcyclohexane (MCH) was studied in a laboratory fixed fluidized bed reactor. The results indicated that higher reaction temperature and lower WHSV tended to produce more ethylene and propylene, among which the reaction temperature was an important factor influencing the ethylene formation. Compared with the FAU and BEA type zeolites, the MFI structured zeolite catalyst, thanks to more acid sites and smaller pore diameter of the catalyst, was conducive to the formation of ethylene and propylene. The protonation occurred on different C—C bonds and C—H bonds in the carbon chain of MCH led to different product slates, and the protonation on C—C bonds located at naphthenic ring was favorable to the formation of ethylene and propylene.     

Optimum Operating and Regeneration Parameters of ZnI_2 Catalyst for Converting Methanol to Triptane:An Ideal Component of Unleaded Aviation Gasoline

Conversion of methanol(MeOH) to 2,2,3-trimethylbutane(triptane) over zinc iodide(ZnI_2)catalyst was investigated in a closed batch reactor.Optimum operating parameters were searched and catalyst deactivation and regeneration behaviors were discussed.The fresh,spent and regenerated catalysts were characterized by XRD,TG and XRF measurements to elucidate the related mechanism.The experimental results showed that the triptane yield reached up to 12.2% under the process conditions,including a reaction temperature of 200℃,an initial pressure of 0.35 MPa,a reaction time of 2 h,and a Me OH to ZnI_2 molar ratio of 2.The catalyst was gradually deactivated after several run cycles.A small amount of iodine was lost and a certain amount of ZnO was formed on the deactivated ZnI_2 catalyst.Deactivation of the catalyst could be attributed to the reduction of ZnI_2 amount,resulted from iodine loss and formation of Zn O.It was firstly pointed out from our work that the deactivated catalyst could be well regenerated by the hydrogen iodide(HI) and the tert-butanol compensation method,wherein the latter was added as an initiator into the reaction system.The activity recovery of the deactivated(spent) catalyst might be related to the reformation of ZnI_2 and acceleration of the initiation step of this reaction.     

三乙胺氯铝酸离子液体催化合成2-异丙基萘

In this paper, 2-isopropyl naphthalene has been synthesized by the reaction of naphthalene and isopropyl bromide, using triethylamine hydrochloride-aluminum chloride ionic liquid as the catalyst. The effect of the catalyst composition, the reaction time, the reaction temperature, the ionic liquid dosage, as well as the molar ratio of the reagents on the 2-isopropyl naphthalene yield was systematically investigated. The optimal reaction conditions cover: an AlCl3 to Et3NHCl ratio of 2.0, a reaction time of 3 h, a reaction temperature of 15.0 ℃, a volume fraction of ionic liquid to the mixture(isopropyl bromide, n-dodecane and n-hexane) of 9%, and a naphthalene/isopropyl bromide molar ratio of 4.0. Under the optimal reaction conditions, the conversion of isopropyl bromide reached 98% and the selectivity of 2-isopropyl naphthalene was equal to 80%. The test results verified good catalytic activity upon using Et3NHCl-AlCl3 ionic liquid as the catalyst for alkylation of naphthalene with isopropyl bromide. The activity of the ionic liquid remains unchanged after it has been recycled for 4 times.     

Preparation of a highly efficient Pt/USY catalyst for hydrogenation and selective ring-opening reaction of tetralin

Ultrastable Y zeolite(USY)-supported Pt catalyst was prepared by gas-bubbling-assisted membrane reduction. The influence of reaction conditions and the metal and acid sites of catalysts on the catalytic performance of catalyst in hydrogenation and selective ring opening of tetralin, 1,2,3,4-tetrahydronaphthalene(THN), was studied. It was found that the optimal reaction conditions were at a temperature of 280 °C, hydrogen pressure of 4 MPa, liquid hourly space velocity of 2 h~(-1) and H_2/THN ratio of 750. Under these optimal conditions, a high conversion of almost 100% was achieved on the 0.3 Pt/USY catalyst. XRD patterns and TEM images revealed that Pt particles were highly dispersed on the USY, favorable to the hydrogenation reaction of tetralin. Ammonia temperature-programmed desorption and Py-IR results indicated that the introduction of Pt can reduce the acid sites of USY, particularly the strong acid sites of USY. Thus, the hydrocracking reaction can be suppressed.     

Promotional Effect of CoO(OH) on Selective Hydrogenation of Maleic Anhydride to γ-Butyrolactone over Supported Ruthenium Catalyst

A decorated ruthenium catalyst was prepared by the coprecipitation method and used for the selective hydrogenation of maleic anhydride(MA) to γ-butyrolactone(GBL). The as-prepared catalyst was characterized by XRD, TGDTG and N2 adsorption techniques. The characterization tests revealed that the catalyst carrier was composed of monoclinic zirconia(m-ZrO2) and hydroxyl cobalt oxide(CoO(OH)). The hydrogenation results showed that the content of CoO(OH), the reaction temperature, the hydrogen pressure and the reaction time significantly affected the catalytic selectivity to GBL. The promotional effect of CoO(OH) was remarkable, which led to an obvious increase in GBL selectivity. An 100% MA conversion and 92.0% selectivity to GBL were achieved over the Ru/ZrO2-CoO(OH)(35%) catalyst in water solvent under the conditions involving a reaction temperature of 180 ℃, a hydrogen pressure of 3.0 MPa, and a reaction time of 6 h.     

Optimization of safflower oil transesterification using the Taguchi approach

Biodiesel is an alternative renewable fuel which is produced by using biomass resources. Its physicochemical properties are close to those of the petroleum diesel fuel. This study highlights biodiesel production from safflower seed oil. The main aim of this experimental work is to optimize the process parameters, namely the methanolto-oil molar ratio, catalyst concentration, reaction time and reaction temperature for biodiesel production. The Taguchi robust design approach was used with an L9 orthogonal array to analyze the influence of process factors on performance parameters. The results showed that the optimum yield of biodiesel was 93.8% with viscosity 5.60 c St, with a methanol-to-oil molar ratio of 4:1, catalyst concentration of 1.5 wt%, reaction time of 90 min and reaction temperature of 60 ℃. The catalyst concentration was found to be the most influencing parameter which contributed 51.1% and 50.8% of the total effect on the yield of biodiesel, Y_1, and viscosity of biodiesel, Y_2, respectively.     

水溶性双金属催化剂催化氯代硝基苯高效选择性加氢制备氯代苯胺

Selective hydrogenation of chloronitrobenzene(CNB) to chloroaniline(CAN) catalyzed by water-soluble Ru/Pt bimetallic catalyst in an aqueous-organic biphasic system was studied. It was found that the catalytic activity increased obviously due to the addition of platinum. Ru/Pt bimetallic catalysts exhibited a strong synergistic effect when the molar ratio of Pt was in the range of 5%—80%. Under the mild conditions including a temperature of 25 ℃, a hydrogen pressure of 1.0 MPa and a Pt molar ratio of 20%, the conversion of p-chloronitrobenzene(p-CNB) reached 99.9%, with the selectivity to p-chloroaniline(p-CAN) equating to 99.4%. The Ru/Pt catalyst also showed high activity and selectivity for the hydrogenation of other chloro- and dichloro-nitrobenzenes with different substituted positions. In addition, the catalyst can be recycled five times without significant loss of activity.     

Propane Dehydrogenation on PtSnNa/AlSBA-15 Catalyst:Influence of Tin as a Promoter

PtSnNa/AlSBA-15 catalysts with different amounts of Sn were prepared for propane dehydrogenation.The catalysts were characterized by XRF,BET,H2 chemisorption,NH3-TPD,H2-TPR,and TPO techniques.Test results indicated that the presence of tin not only modified the acid function and the interfacial character between metal and support,but also reduced the coke deposition effectively.Among these catalysts investigated thereby,the PtSn(0.7%)Na/AlSBA-15 catalyst had the best catalytic performance in terms of propane conversion and stability.With the continuous addition of Sn,more amounts of Sn0 species appeared,which was unfavorable to the reaction.The PtSn(0.7%)Na/AlSBA-15 catalyst was parametrically characterized in order to obtain necessary information to integrate the process operating conditions.A weight hourly space velocity of 3 h-1,a reaction temperature of 610 ℃ and a H2/C3H8 molar ratio of 0.25 were found to be optimum conditions for achieving a higher dehydrogenation activity of the catalyst.     

Investigation of Propene Oligomerization Catalyzed by Phosphotungstic Acid Catalysts

In this paper,the propene oligomerization reaction catalyzed by phosphotungstic acid supported on two kinds of silica gel was studied,it had been found out that the conversion of propene catalyzed by the type A silica gel-phosphotungstic acid catalyst was 3.38m%,while the conversion of propene catalyzed by the type B silica gel-phosphotungstic acid catalyst was 90.1m% with a nonene selectivity of 42.33m%,and a dodecene selectivity of 31.79m%.The influence of reaction temperature,pressure and liquid hourly space velocity(LHSV) on the reaction catalyzed by the type B silica gelphosphotungstic acid catalyst was investigated.It had been verified that when the reaction temperature increased from 170℃ to 190℃,the conversion of propene increased while the selectivity of nonene and dodecene decreased;when the reaction pressure increased from 3.5 MPa to 4.5 MPa,the conversion of propene increased also,and the selectivity of nonene and dodecene changed very little.The conversion of propene at a space velocity of between 0.5h-1 and 1.0h-1 was higher than that achieved at 2.0h-1,but the selectivity of nonene and dodecene did not show regular fluctuations.An optimum conversion of propene(91.05m%) and an optimum selectivity of nonene and dodecene(89.51m%) could be achieved at a reaction temperature of 170℃,a reaction pressure of 4.5MPa,and a LHSV of 1.0h-1.The experiments on catalyst life showed that the activity of the type B silica gel-phosphotungstic acid catalyst could be only maintained in 25 hours,and the reason was explained also.