超顺磁负载型催化剂 H3PW12O40/γ-Fe2O3催化噻吩和烯烃的烷基化反应简

The alkylation of sulfur compounds with olefine is considered to be an attractive way to attain high level of sulfur removal by raising the boiling point of sulfur-containing compounds to ease their separation from lighl fractions by distillation. A series of superparamagnetic supported catalysts, used for alkylation of thiophene with 1-octene, were prepared by loading H3PW12040 （HPW） onto commercially available nanoparticles γ-Fe2O3 through incipient wet impregnation method. The catalysts were characterized by X-ray diffraction （XRD）, Fourier transform infra-red （FT-IR）, thermo gravimetric analysis （TG）, N2-adsorption and vibrating sample magnetometer （VSM）. The physicochemical characterization reveals that 7-Fe203 could be accommodated to immobilize and disperse HPW. Moreover, possessing high magnetization of 26.1 A.mZ.kg-1 and with mesoporous structure with specific surface area of 35.9 m2·g^-1, the 40% （by mass） HPW loading catalyst is considered the proper catalyst for olefinic alkylation of thiophenic sulfur （OATS） and can be separated in an external magnetic field. The catalytic activity was investigated in the alkylation reaction of thiophene with 1-octene, and the conversion of thiophene is up to 46% at 160 ℃ in 3 h. The 40% （by mass） H3PW12O40/γ-Fe2O3 catalyst can be reused 6 times without too much loss of activit and keeps its property of superparamagnetism.     

超顺磁催化剂H3PW12O40/Fe3O4@SiO2的制备、结构表征及在汽油烷基化脱硫中的应用

采用改进Stöber法制备超顺磁Fe₃O₄@SiO₂复合粒子作为催化剂载体,再通过浸渍法将H₃PW₁₂O₄₀（HPW）负载在Fe₃O₄@SiO₂载体上,制备了一系列超顺磁负载型催化剂HPW/Fe₃O₄@SiO₂。并使用X射线衍射（XRD）、傅里叶红外（FT-IR）、氨的程序升温脱附（NH₃-TPD）、扫描电镜（SEM）、N₂吸附-脱附和振动样品强磁计（VSM）对催化剂进行表征。结果表明,HPW固定并均匀分散在Fe₃O₄@SiO₂载体上,40% HPW/Fe₃O₄@SiO₂催化剂具有较高的饱和磁强度 （30.1 emu·g^-1）和较大的比表面积 （303.6 m²·g^-1）,并可用外加磁场进行分离。采用40% HPW/Fe₃O₄@SiO₂催化噻吩与1-辛烯组成的模拟汽油的烷基化脱硫反应,在160℃下反应2 h,噻吩转化率达到85.5%,有较好的催化脱硫性能,且可以多次循环利用。     

The performance of HMCM-22 zeolite catalyst on the olefin alkylation thiophenic sulfur in gasoline

The catalytic performance of the HMCM-22 zeolites with different Si/Al₂ ratios for the olefin alkylation thiophenic sulfur (OATS) process was investigated. With the Si/Al₂ ratio decreasing, the catalytic activity of the HMCM-22 zeolite was increased clearly due to the acidity increment. Further, the thiophene alkylation activity was increased much faster than the xylene alkylation and the hexene oligomerization for the reactivity difference of thiophene, xylene and hexene. When the Si/Al₂ ratio decreased from 473 to 98, the thiophene alkylation activity first reached its quasi-plateau value and its selectivity got a maximum, while after that the increased acid sites would more transfer to the hexene oligomerization and the xylene alkylation, thus improved their activity and decreased the selectivity of thiophene alkylation.     

FCC gasoline desulfurization using a ZSM-5 catalyst: Interactive effects of sulfur containing species and gasoline components

This study evaluates the influence of gasoline hydrocarbon components on thiophene conversion over H-ZSM5 zeolite. Experiments are carried out in a CREC fluidized riser simulator under mild conditions using thiophene/hydrocarbon mixtures as representatives of gasoline. Results show a high and selective thiophene conversion, forming H₂S, aromatics, alkyl-thiophenes, benzothiophene, and coke. It is also found that gasoline octane number is enhanced and olefin content reduced. This is accomplished with minimum gasoline losses. On the basis of the data reported it is hypothesized that thiophene conversion takes place via ring opening and alkylation, with gasoline hydrocarbon components having key roles as hydrogen donors in thiophene ring opening reactions as well as co-reactants in thiophene alkylation. These observations are in good agreement with previous thermodynamic and kinetic analysis developed using sulfur containing compounds by the CREC-UWO research group [4] and [10].     

树脂催化重汽油烷基化硫转移的动力学研究

采用树脂催化剂,研究重汽油中噻吩类硫化物的烷基化硫转移性能,分析反应前后硫分布的变化,并对反应动力学进行研究。结果表明,在反应温度110℃和反应时间60 min条件下,烷基化硫转移率大于90%,其反应动力学为一级反应速率方程,反应活化能为20.32 kJ·mol~(-1),指前因子为1 364 h~(-1),噻吩类硫化物烷基化反应的动力学方程可表示为:r=1364exp(-2.445×10~3/T)c_T。     

Kinetics and mechanism of liquid-phase alkylation of 3-methylthiophene with 2-methyl-2-butene over a solid phosphoric acid

Drastic regulations concerning sulfur content in fuels require the development of new processes in the refineries. In the case of gasoline, AOTS process based on the alkylation of thiophene by butenes was proposed. In the present work, we attempted to describe the mechanism of such a reaction with model molecules. Liquid-phase alkylation of 3-methylthiophene with 2-methyl-2-butene was performed on supported phosphoric acid. It is shown that this reaction is mainly selective to monoalkylation products. The kinetics is following an Eley–Rideal law and the reaction intermediate seems to be an ester of phosphoric acid or polyphosphate.     

Study on Olefin Alkylation of Thiophenic Sulfur in FCC Gasoline Using La2O3-Modified HY Zeolite

HY zeolite modified by La₂O₃ on olefin alkylation of thiophenic sulfur in fluid catalytic cracking (FCC) gasoline was studied in the micro fixed-bed reactor. Reaction pressure 1.5 MPa, reaction temperature 180 °C, WHSV 3.5 h^?1, using HY zeolite modified by 2% La₂O₃, the conversion of thiophene sulfur promoted nearly 10% with good selectivity, comparing with no-modified by La₂O₃. Acidity of modification of HY zeolite with La₂O₃ was tested in Pyridine–IR, it showed that increasing the amount of weak Bronsted (B) acid and the ratio of total B acid with total Lewis (L) acid could strengthen the hydrogen transfer activity of the catalyst, which leaded to improving the capacity of thiophene alkylation. The X-ray diffraction (XRD) results showed that the structure of catalysts could be optimized by loaded proper amount of La₂O₃ for promoting the acidic properties of HY zeolite.     

碱处理ZSM-5分子筛上噻吩烷基化性能的研究

用Na2CO3溶液处理Si/Al=50的ZSM-5分子筛,以模型化合物为原料,在小型连续固定床反应器上,考察了Na2CO3溶液浓度对噻吩烷基化性能的影响。结果表明,在反应温度为360℃,压力为1 MPa,液时空速1.5 h-1,Na2CO3溶液浓度为4 mol/L时,噻吩转化率最高为90.5%。     

Two-photon absorption properties of push–pull oxazolones derivatives

New fluorescent oxazolone derivatives with high two-photon absorption cross-section were synthesized. Electron donor (phenyl, dimethylaniline and furanyl) and acceptor (nitrobenzene and ethenyl-phenyl-benzimidazol) groups have been appended to the methylene end of 4-(methylidene)-2-phenyl-1,3-oxazol-5(4H)-one in order to produce an highly conjugated π-system with push–pull geometry. The linear and nonlinear optical properties of the oxazolones have been determined. The compounds with a high charge transfer from the substituent group to the oxazolone ring have relatively high two-photon absorption cross-sections (80–100 GM). The best performing nonlinear fluorophore being the benzimidazol derivative with a two-photon absorption cross-section of 80 GM and a relatively high emission quantum yield, ϕ = 0.31.     

Friedel‐crafts alkylation of diphenyl oxide with 1‐decene over sulfated zirconia as catalyst

Friedel‐Crafts alkylation and acylation reactions, using highly polluting homogeneous Lewis and Bronsted acids, are ubiquitous in a variety of organic process industries. In many cases very high conversions and selectivities can be achieved with aluminum chloride as catalyst and nitrobenzene as a solvent. However, environmental concerns associated with aluminum chloride‐nitrobenzene or BF3‐HF or mineral acids catalysts have encouraged development of solid acids, which not only intensify the rates of reactions but also offer better product selectivity. Amongst these catalysts, sulfated zirconia has gained a considerable importance due to its super‐acidity under certain conditions. The alkylation of diphenyl oxide with 1‐decene was studied over sulfated zirconia catalyst and it leads to industrially important products. The surface reaction between chemisorbed 1‐decene diphenyl oxide from the liquid phase, in the absence of any mass transfer resistance, was found to be the rate determining step with Eley‐Rideal type of mechanism.     

Site of alkylation in pyrimidine derivatives: Studies on the structure of 1-Alkyl-4-amino-6-methylpyrimidinium Iodides

The alkylation of 4-amino-6-methylpyrimidines ( 1a-f ) in DMSO or nitrobenzene at room temperature affords the ¹N-alkylated products 2a-h . Treatment of 1a-c with an excess of methyl iodide in the presence of powdered alkali metal hydroxides/DMSO gives the pyrimidinium salts 2g , i , j. Carbon-13 n.m.r. and X-ray studies have shown that in the case of compounds 2 the polymethine structure B is preferred.     

HY分子筛催化噻吩类硫化物的烷基化反应动力学

以HY分子筛为催化剂,考察流化催化裂化(FCC)汽油中的噻吩类硫化物的烷基化反应性能,并对反应动力学进行研究。结果表明:在反应温度433 K,反应时间1 h时烷基化硫转移率(低于393 K的馏分)达到90%以上,反应温度在403～433 K,FCC汽油中的噻吩类硫化物烷基化反应动力学方程符合一级反应速率方程,其活化能为44.70 kJ/mol,指前因子为6.47×105h-1。     

AlCl3-磺酸树脂催化噻吩类硫化物与异丁烯烷基化硫转移反应

选择以噻吩的甲基取代衍生物(包括2-甲基噻吩、3-甲基噻吩及2,5-二甲基噻吩)与异丁烯的烷基化反应为模型反应,考察了经三氯化铝气相固载法改性的CT175树脂催化剂催化噻吩的甲基取代衍生物与烯烃的烷基化反应性能. 研究结果表明,负载AlCl3的CT175树脂催化剂对催化2-甲基噻吩、3-甲基噻吩及2,5-二甲基噻吩与异丁烯的烷基化硫转移反应均具有很高的活性,在80℃、常压、异丁烯(与氮气按摩尔比1:1配制的混合气)流量5.0 mL/min、液体(含模型硫化物2-甲基噻吩、3-甲基噻吩及2,5-二甲基噻吩的浓度分别为2033, 2045, 1543 mg/g的苯溶液)质量空速为2.5 h-1的条件下,上述5种模型硫化物均接近于完全转化. 对催化剂的活性稳定性进行了为期30 d的连续考察,结果表明,3种模型硫化物的烷基化转化率均高于99%,且催化剂活性未见下降趋势.     

Hydrogenation of Nitrobenzene with Supported Transition Metal Catalysts in Supercritical Carbon Dioxide

Transition metal catalysts such as Pd, Pt, Ru, and Rh supported on carbon, silica and alumina have been examined for the hydrogenation of nitrobenzene (NB) in supercritical carbon dioxide (scCO₂) and in ethanol. The order of hydrogenation activity is Pt>Pd>Ru, Rh in scCO₂ and in ethanol. The effectiveness of the support is C>Al₂O₃, SiO₂ for either Pt or Pd in scCO₂. For all the catalysts, higher selectivity to aniline has been obtained in scCO₂ compared with ethanol. Hydrogenation of nitrobenzene catalyzed with Pd/C and Pt/C catalysts was successfully conducted in scCO₂ with a 100% yield to aniline at a lower reaction temperature of 35 °C. The product aniline (organic phase) can be easily separated from the side‐product water (aqueous phase), solvent (scCO₂), and catalyst (solid) by a simple phase separation process. The hydrogenation of NB is a structure‐sensitive reaction in ethanol as well as in scCO₂ except for a few Pt/C catalysts in which the degree of metal dispersion is small (<0.08).     

Thiophene conversion under mild conditions over a ZSM-5 catalyst

Refiners are nowadays actively considering the post-treating FCC gasoline processes as a viable and less costly approach for meeting sulfur environmental regulations. Most promising catalytic desulfurization processes do not require hydrogen addition, including between others the use of zeolites as adsorbents/catalysts. This type of desulfurization leads to the formation of significant amounts of coke, requiring keeping high catalyst activity a continuous twin fluidized bed system (fluidized-bed reactor, fluidized bed regenerator). This study evaluates the catalytic conversion of thiophene and/or thiophene in n-octane mixtures. Catalytic experiments are carried out in the CREC riser simulator under mild conditions, using H-ZSM5 zeolite dispersed in a silica matrix. The experimental results obtained demonstrate a higher selective conversion of thiophene over n-octane. It is shown that thiophene conversion proceeds via ring opening and alkylation yielding H₂S, alkyl-thiophenes, benzothiophene, and coke, with no measurable thiophene saturation or dimerization reactions observed. The experimental results are also supported with an extensive thermodynamic analysis that includes all the possible thiophene conversion pathways over zeolites. On this basis and using as a reference the observable measurable species, a reaction network is proposed to represent the thiophene catalytic conversion under the suggested gasoline post treatment conditions.     

Reaction Coupling of Ethylbenzene Dehydrogenation with Nitrobenzene Hydrogenation

The chemical equilibrium for the coupling of ethylbenzene dehydrogenation with nitrobenzene hydrogenation, to produce styrene and aniline simultaneously, has been calculated on the basis of the Soave–Redlich–Kwong equation of state. The dehydrogenation of ethylbenzene in the presence of nitrobenzene over the catalysts -Al₂O₃, ZSM-5, activated carbon and platinum supported on activated carbon has been carried out at 400 °C. The effects of Pt loading and the pretreatment of the catalysts have been investigated. It has been revealed that the conversion of ethylbenzene can be greatly improved by the reaction coupling due to the elimination of the hydrogen produced in the reaction by the hydrogenation of nitrobenzene. Platinum supported on the activated carbon has been suggested as a suitable catalyst. The best results with ethylbenzene conversion of 33.8% and styrene selectivity of 99.2% were obtained over Pt(0.02 wt%)/AC at 400 °C. Moreover, such process is also energetically favored since the necessary process heat to drive the ethylbenzene dehydrogenation can be provided by the coupling with the exothermic nitrobenzene hydrogenation reaction.     

Effects of oxygenates and moisture on adsorptive desulfurization of liquid fuels with Cu(I)Y zeolite

Oxygenates (i.e., ethanol and MTBE as required additives in gasoline) and moisture were found to have strong inhibiting effects on desulfurization by adsorption with zeolite. The effects of each individual molecule were studied quantitatively by using a model fuel (500 ppmw thiophene in 80% n-octane + 20% benzene). Cu(I)Y was used as the π-complexation sorbent. Ab initio molecular orbital calculations showed that the adsorption bond energies with Cu(I)Y were: 21.4 kcal/mol for thiophene; 31.0 kcal/mol for MTBE and 41.6 kcal/mol for ethanol. Separation or selectivity factors can be estimated from heats of adsorption, and the inhibiting effects were predicted to follow the order of the relative heats of adsorption: water > ethanol > MTBE > thiophene. The inhibiting effects were measured by the decreases in the desulfurization capacities of Cu(I)Y in the presence of each additive in the model fuel. The results were in agreement with the theoretical prediction. In addition, the desulfurization capacity was strongly dependent on the liquid hourly space velocity because of the diffusion limitation of thiophene in the zeolite crystals.     

The copolymerization of 2- and 3-vinyl thiophene with α-methylene-γ-butyrolactone

Summary Binary copolymers of 2- and 3-vinyl thiophene were synthesized via freeradical initiated bulk polymerization. The copolymerizations proceeded readily at 65°C to yield copolymers of reasonable molecular weight. The 2-vinyl thiophene monomer was found to be more reactive than the α-methylene-γ-butyrolactone, while the 3-vinyl thiophene was found to be less reactive than the lactone.     

Analysis of the 300 and 600 MHz1H-NMR spectra of poly(3-vinyl thiopene)

Summary The 300 and 600 MHz¹H-NMR spectra of poly-(3-vinyl thiophene) synthesized via free radical initiated polymerization are presented and analyzed. The spectra are similar to those of poly-(2-vinyl thiophene) and were interpreted in a like manner. The polymer was found to be atactic with a P_m value of 0.48±.05.     

Thermodynamic properties of 1‐ETHYL‐3‐methylimidazolium methanesulphonate with aromatic sulphur,nitrogen compounds at T = 298.15–323.15 K and P = 1 bar

This work investigates the ability of 1‐ethyl‐3‐methylimidazolium methanesulphate ([EMIM][MeSO₃]) as a green and tuneable solvent for denitrification and desulphurisation studies. Experimental density, surface tension and refractive index data have been measured for the following systems: [EMIM][MeSO₃] (1) + pyridine (2), [EMIM][MeSO₃] (1) + pyrrole (2), [EMIM][MeSO₃] (1) + quinoline (2), [EMIM][MeSO₃] (1) + indoline (2), [EMIM][MeSO₃] (1) + thiophene (2) and [EMIM][MeSO₃] (1) + water (2) over the entire mole fraction of [EMIM][MeSO₃] at T = 298.15–323.15 K and P = 1 bar. Further from experimental density, surface tension and refractive index, coefficient of thermal expansivity, excess molar volume, deviation of surface tension and refractive index deviation were also calculated. It was found that the heteroaromatic nitrogen/sulphur compounds are completely miscible in [EMIM][MeSO₃]. The surface tension values were found to increase while the refractive index decreases with increasing mole fraction of [EMIM][MeSO₃]. The experimental values for surface tension increased in the order: pyridine > thiophene > pyrrole > indoline > quinoline > water and for refractive index: pyridine > pyrrole > indoline > quinoline > thiophene > water. It was found that the composition of [EMIM][MeSO₃] has a greater influence than temperature in deciding the surface, optical and thermodynamic properties for similar molecular interaction such as IL–thiophene and IL–pyrrole than dissimilar molecules such as IL–water. Further quantum chemical‐based COSMO‐RS tool was used to estimate the activity coefficient at different composition. © 2012 Canadian Society for Chemical Engineering