The alkylation reaction of benzene with methanol to produce toluene: Y-C and Y-CCs catalyst

The secondary reaction of toluene is difficult to be suppressed in benzene alkylation with methanol over conventional acidic zeolite catalysts. Moreover, the formation of coke yet remains a challenging problem. In this study, Na-Y zeolites were modified with ammonium carbonate (AC), citric acid (CA) and caesium nitrate(CN) to evaluate the alkylation of benzene with methanol, which was also characterized by XRD, SEM, FT-IR, N₂ adsorption and Py-IR. For the Na-Y treated with AC-CA-CN, not only the catalytic selectivity for the alkylation of benzene with methanol was improved (the total selectivity of toluene and xylene was 97.9% and toluene selectivity was 86.4%), but also the quantity of coke was greatly decreased.     

Pt改性分子筛催化剂上丙烷与苯的烷基化反应

研究了不同分子筛负载的Pt催化剂上丙烷与苯的烷基化反应.结果表明,Pt/HZSM-5具有较好的催化性能.在0~0.3%范围内提高Pt负载量可以提高催化剂的催化活性和生成C9以及C10 芳烃的选择性,降低非芳烃产物的选择性.较低的反应温度、较高的苯/丙烷摩尔比和较高的空速有利于烷基芳烃的生成.     

有机杂化介孔Beta分子筛的合成及在苯甲醇烷基化反应中的应用

针对沸石分子筛在苯甲醇和三甲基苯的烷基化催化反应应用中存在催化活性低及微孔孔道内大量苯甲醇自醚化副反应导致产物选择性低这一难题, 通过引入等级孔结构提高外比表面积和有机杂化修饰封堵微孔孔道的双重策略, 在大幅提升可接触的外表面活性中心数量的同时有效降低苯甲醇进入微孔孔道内发生自醚化副反应, 开发出具有高反应活性及烷基化产物选择性的有机杂化介孔Beta分子筛材料, 大幅度提升了其对苯甲醇和三甲基苯的烷基化反应的催化活性和产物的选择性, 使苯甲醇的转化率从66.8%提升到了99.7%, 烷基化产物的选择性从14.8%提高到50.7%. 本工作为开发高活性及高选择性的烷基化催化剂提供了新的思路.     

大孔沸石催化剂上苯与丙烯液相烷基化反应行为的研究

围绕具有工业实用价值的苯与丙烯液相烷基化制取异丙苯这一课题,对比考察了不同硅铝组成的ＨＹ型和Ｈβ型沸石的催化性能,利用烧炭试验、结炭前驱物萃取方法及色－质谱表征手段探索了沸石催化剂在烷基化反应中的结炭行为。烷基化试验结果表明,β沸石对异丙苯的选择性和催化剂稳定性都明显优于Ｙ型,其异丙苯选择性可达９６ｍｏｌ％以上。同时,提高原料苯烯比、降低反应温度或保持适当高的进料空速能够提高异丙苯的选择性。结炭催化剂的烧炭结果显示,在烷基化反应中Ｈβ比ＨＹ具有较强的抗结炭能力。结炭催化剂的溶剂萃取结果表明,反应中的液相苯能够有效地使催化剂孔道中的结炭前驱物种脱离催化剂表面,从而抑制结炭,提高催化剂的稳定性     

A novel catalyst for alkylation of benzene

In this research, acid-activated and pillared montmorillonite were prepared as catalysts for alkylation of benzene with 1-decene for production of linear alkyl bebzene (LAB). The catalysts were characterized by X-ray diffraction (XRD), FT-IR spectroscopy, scanning electron microscopy (SEM), N₂ adsorption-desorption isotherms, temperature programmed desorption (TPD) of NH₃ and elemental and thermal analysis techniques. The reaction conditions were optimized by varying catalyst concentration, reactants ratio and temperature in a batch-slurry reactor. It was found that acid-activation increased the porosity and surface acidity of the catalysts. Pillaring of the sample improved the surface area, micro-mesoporosity and acidity. Under optimized conditions more than 98% conversion of 1-decene was observed. All products were LABs and no major side reaction was observed.     

分子筛催化剂在苯与烯烃烷基化中的研究进展

介绍了国内外分子筛催化剂在苯与烯烃烷基化中的研究进展情况,侧重介绍了微孔分子筛、介孔分子筛和复合分子筛的应用;指出烷基苯一般通过苯与烯烃烷基化反应制得,分子筛催化剂是催化制取烷基苯的一种环境友好型固体酸催化剂.同时提出,今后应进一步深入研究符合环保要求和工业化需求的新型改性分子筛催化剂.     

Alkylation of benzene with 1-hexene in acidic ionic liquid systems: Et3NHCl-FeCl3and Et3NHCl-AlCl3ionic liquids

Summary The alkylation of benzene with 1-hexene has been investigated in different triethylamine hydrochloride-ferric chloride (Et₃NHCl-FeCl₃) and triethylamine hydrochloride-aluminium chloride (Et₃NHCl-AlCl₃) ionic liquids. Both high catalyst activity and monoalkylation selectivity were observed for these two type of ionic liquids. Systems prepared by modification with HCl in Et₃NHCl-FeCl₃ionic liquids prove to be very suitable solvents and catalysts for the reaction. When employing Et₃NHCl-AlCl₃ionic liquids as catalysts, the reaction takes place in biphasic mode with facile catalyst separation and catalyst recycling.     

多级孔结构WO3/ZrO2固体酸催化剂的烷基化催化性能研究

采用复合模板表面活性剂辅助水热法一步合成WO3/ZrO2体系多级孔固体酸催化剂,探讨了煅烧温度对所合成催化剂试样酸强度及酸量的影响,并考察了催化剂针对苯和十二烯的烷基化反应中的催化性能.结果表明,WO3/ZrO2体系催化剂具有较强的酸强度,并且与催化剂的比表面积和晶化程度有密切关系,比表面积的增大和四方相ZrO2的生成能有效地提高催化剂的酸强度.该催化剂具有优良的烷基化反应催化活性和选择性,其中450℃,5h煅烧的WO3/ZrO2催化剂样品酸性最强,其烷基化催化活性和选择性最优.     

Effect of zeolite pore morphology on solvent-less alkylation of benzene with 1-hexene

In an attempt to convert the carcinogenic benzene which is almost restricted for its use in gasoline, alkylation reaction with olefin 1-hexene has been conducted on various zeolites. Four zeolites having different pore topology and pore size have been applied as solid acid catalysts for effective production of alkylate in a liquid phase, solvent-less low temperature reaction. The textural properties of all the four zeolites (ZSM-5, MOR, BEA, HY) have been characterized for crystal morphology by TEM, crystal structure by XRD and FTIR, BET for surface area, N₂ sorption for porosity and TPD for acidity. Among the zeolite, BEA possessed high surface area (600.61 m²/g) and enhanced meso pores volume (0.3956 cm³/g) as compared to other zeolite samples. The performance of BEA was also observed to be superior in the liquid phase alkylation of benzene with 1-hexene in a batch reactor under autogenous pressure without using any solvent. At the optimum reaction conditions, the benzene conversion was 86.6 wt% and 3-Phenylhexane, 2-Phenylhexane yield were about 47.9 wt% and 38.7 wt% respectively on this catalyst. The BEA also exhibited longer time-on-stream and reusability performance, thus offers an attractive route for converting benzene into valuable (3-Phenylhexane, 2-Phenylhexane) alkylate product useful for the manufacturing of fine chemicals, dyestuff, detergents and scents.     

酸处理和负载ZnCl2粘土结构的影响及应用研究

目前,Ｆｒｉｅｄｅｌ－Ｃｒａｆｔｓ反应的催化剂主要还是容易造成严重污染的ＡｌＣｌ３,ＺｎＣｌ２和ＦｅＣｌ３等酸性氯化物。随着环保呼声的日益高涨,有的地方已实行环保一票否决制,故寻找可以代替ＡｌＣｌ３类的环境友好固体酸催化剂,已成为化工生产中的当务之急...     

Catalytic alkylation of pyrocatechol with camphene

Regularities of the pyrocatechol alkylation with camphene in the presence of aluminum-containing homogeneous catalysts and heterogeneous acid catalysts were studied. The effect of the catalyst type on the reaction selectivity and the product composition was established. The most selective heterogeneous catalyst for the C-alkylation of pyrocatechol is montmorillonite KSF, which leads to a rearrangement of the terpene fragment to isocamphyl structure. Homogeneous organoalyuminum compounds are found to be nonselective catalysts for the alkylation of pyrocatechol at the benzene ring.     

Catalytic properties of the Cr-HMS materials in the benzylation of benzene with benzyl chloride

A series of chromium-containing mesoporous silicas with different Cr contents were prepared and characterized with chemical analysis, N₂ adsorption measurements (BET equation and BJH theory), X-ray diffraction, diffuse reflectance UV-visible and H₂-temperature programmed reduction techniques. Excellent results in benzylation of benzene and substituted benzenes employing benzyl chloride as the alkylating agent were obtained. The mesoporous chromium-containing materials showed both high activity and high selectivity for benzylation of benzene. The activity of these catalysts for the benzylation of different aromatic compounds is in the following order: benzene > toluene > p-xylene > anisole. Kinetics of the benzene benzylation over these catalysts has also been investigated.     

Highly active and stable immobilized aluminium chloride catalyst for alkylation of benzene with 1-dodecene

Summary An AlCl₃ catalyst immobilized on<span lang=EN-US style='font-family:Symbol;mso-bidi-font-family: Symbol;mso-ansi-language:EN-US'>g-Al₂O₃with meso- and macro-pore bimodal structure was prepared and studied in the alkylation of benzene with 1-dodecene in a suspension bed reactor. The catalyst exhibited high activity, selectivity and stability during 1000 h running, with a 1-dodecene conversion of more than 95%, monoalkylbenzene selectivity of 92%, and 2-phenyldodecane (2-Ph) selectivity of nearly 42%.</o:p>     

Transition metal-catalyzed olefin arylation via C–H bond activation of arenes

In this article, two kinds of our transition metal-catalyzed olefin arylations are summarized and discussed. The first one is Ir-catalyzed novel anti-Markovnikov hydroarylation of olefins with benzene. Using this reaction catalyzed by [Ir(μ-acac-O,O′,C₃)(acac-O,O′)(acac-C₃)]₂ (acac = acetylacetonato), 1, straight-chain alkylarenes, which were not obtainable by the conventional Friedel-Crafts aromatic alkylation with olefins, were able to be successfully synthesized directly from arenes and olefins with the higher selectivity than that of branched alkylarenes. This is the first efficient catalyst which shows the desirable high regioselectivity. The reaction of benzene with propylene gave n-propylbenzene and cumene in 61% and 39% selectivities, respectively, and the reaction of benzene and styrene afforded 1,2-diphenylethane in 98% selectivity. The reaction of alkylarene and olefin showed meta and para orientations. A wide range of olefins and arenes can be employed for the synthesis of alkylarenes. The mechanism of the reaction involves C–H bond activation of benzene by Ir center to form Ir–phenyl species. The second reaction is Rh-catalyzed oxidative arylation of ethylene with benzene to directly produce styrene, namely one-step synthesis of styrene. The reaction of benzene with ethylene catalyzed by Rh(ppy)₂(OAc) (ppyH = 2-phenylpyridine, OAc = acetate), 3 with Cu oxidizing agent gave styrene and vinyl acetate in 77% and 23% selectivities, respectively, in contrast to those by Pd(OAc)₂, 47% of styrene and 53% of vinyl acetate. The mechanism of the reaction involves Rh-mediated C–H bond activation of benzene, which appears to be a rate-determining step. Furthermore, Rh complexes in a Rh(I) oxidation state at the beginning of the reaction work as catalysts for the reaction by addition of acacH and O₂ without any oxidizing agent, like Cu salt.     

ORTHO-selective phenol methylation over iron-magnesium oxide catalysts

Alkylation of phenol to ORTHO-cresol and 2,6-xylenol with methanol in the presence of iron and iron-magnesium oxide catalysts was investigated. The catalysts displayed high activity and stability. Addition of magnesium oxide to the iron catalyst increases its selectivity towards C-alkylation in ortho-position. It was found that the active phase in the investigated catalysts is highly dispersed magnetite or mixed spinel of Fe(MgFe)O₄ type. It is noticed that if Fe⁺² ions are replaced by Mg⁺² ions in the spinel the basicity of the bifunctional catalyst is augmented, increasing ortho-selectivity of alkylation.     

Benzene alkylation with propane over metal modified HZSM-5

Propane alkylation with benzene over modified zeolite catalysts is one of the good ways for propane utilization. The catalytic performance over various metal modified HZSM-5 catalysts was studied. Addition of Pt or Zn resulted in remarkable increase of the activity. Addition of Mo depressed the activity, but greatly improved selectivity to aromatics, with the content of products from direct addition of propyl group to benzene (IPB and NPB) in the products reaching 81.5 mol%.     

Catalysis and deactivation of SO 4 2− /ZrO2 solid acid on the alkylation of benzene with 1-dodecene

Catalysis and deactivation of SO₄²⁻/ZrO₂ solid acid on the alkylation of benzene and 1-dodecene were studied by the characterization of XRD, BET, IR, TG/DTA, and NH₃-TPD techniques and the determination of the 1-dodecene conversion, the yield of dodecylbenzene and the selectivity of linear alkylbenzene respectively. In addition, some treatment methods, such as the extraction with benzene or THF as solvent, and the calcinations with or without the dipping of H₂SO₄ in air, were respectively used to recover the activity of deactivated catalyst. The results indicate that SO₄²⁻/ZrO₂ solid acid shows higher catalytic activity for the alkylation of benzene and 1-dodecene with nearly 100% of 1-dodecene conversion and more than 80% of dodecylbenzene yield, and higher selectivity of 2-LAB. The activity of catalyst for the alkylation of benzene is in proportion to the content and the strength of medium acid site. However, the distinct deactivation of catalyst was also obversed in the alkylation. According to the characterization of deactivated catalyst, the accumulation of hydrocarbon fragment and the removal of are mainly reasons of SO₄²⁻/ZrO₂ deactivation. The SO₄²⁻/ZrO₂ calcinated at higher temperature is apt to deactivate. The treatment by extraction with solvent or calcinations can recover the catalytic activity of spent catalyst at a certain extent, especially calcination with the dipping of H₂SO₄. Published in Russian in Kinetika i Kataliz, 2009, Vol. 50, No. 3, pp. 455–463. The article is published in the original.     

柠檬酸改性Hβ分子筛上的苯与丙烯烷基化反应

研究了柠檬酸改性对Hβ分子筛上苯与丙烯烷基化反应性能的影响。通过比较分析改性前后催化剂寿命、二异丙苯选择性及其异构体组成分布等的变化。结果表明，二异丙苯的选择性及各异构体的分布与催化剂的酸密度和酸强度有关；较高酸密度和酸强度有利于烷基转移反应的进行，但却加快了催化剂的失活。柠檬酸改性处理可调节Hβ分子筛的酸密度和酸强度，改善苯烷基化的催化反应性能。经0.50mol/L的柠檬酸处理后，Hβ催化剂的寿命比原来延长30%，正丙苯的质量分数减少90%。     

A high hydroarylation activity of K2PtCl4/AgOTf catalyst in the reaction of propiolic acid with unactivated and activated arenes

A mixed catalyst K₂PtCl₄/AgOTf showed the highest activity for hydroarylation of propiolic acid, among palladium and platinum catalysts. This catalyst was effective for hydroarylation with less reactive benzene to give cis-cinnamic acid in good yield. The hydroarylation with toluene gave a higher yield of hydroarylation products than that with benzene and resulted in ortho/para orientation with an almost statistical ratio, suggesting that the result is very close to that of the Friedel-Crafts alkylation with methyl bromide or p-nitrobenzyl chloride. Hydroarylation of propiolic acid with other electron-rich arenes proceeded efficiently in the presence of the K₂PtCl₄/AgOTf catalyst in trifluoroacetic acid forming cis-cinnamic acids in good to high yields. This method was also applied to hydroarylation of ethyl propiolate.     

Direct Dual‐Template Synthesis of MWW Zeolite Monolayers

A two‐dimensional zeolite with the topology of MWW sheets has been obtained by direct synthesis with a combination of two organic structure‐directing agents. The resultant material consists of approximately 70 % single and double layers and displays a well‐structured external surface area of about 300 m² g^?1. The delaminated zeolite prepared by means of this single‐step synthetic route has a high delamination degree, and the structural integrity of the MWW layers is well preserved. The new zeolite material displayed excellent activity, selectivity, and stability when used as a catalyst for the alkylation of benzene with propylene and found to be superior to the catalysts that are currently used for producing cumene.