改性ZSM-5分子筛催化甲苯、甲醇苯环烷基化反应的研究进展

综述了近三十年来国内外有关在改性ＺＳＭ－５沸石催化剂上,甲苯、甲醇苯环烷基化制备对二甲苯反应的研究状况。经过改性的ＸＳＭ－５型沸石具有合适的孔径和适当强度及数量的表面酸中心,有利于反应活性及选择性的提高。参考文献１４５篇。     

FeZSM-5/N2O催化氧化苯制苯酚

苯一步氧化制苯酚,是有机物氧化合成中富有挑战性的研究课题之一。该文着重论述了在FeZSM-5及其一系列沸石催化剂上,应用氧化亚氮作为氧化剂使苯直接氧化制苯酚的研究进展。这一系列催化剂体系的特殊之处在于通过氧化亚氮在沸石分子筛上的分解获得具有催化活性的a－氧。详细讨论了在沸石分子筛上形成特殊结构的铁氧化物作为催化活性中心这一观点。由于这种催化体系对苯直接氧化制苯酚的反应有着很高的选择性,因此,这种比较经济和安全的制备苯酚的方法引起了人们的广泛关注。     

V-AlPO5分子筛催化苯直接羟基化制苯酚

采用水热法合成了V-AlPO5分子筛催化剂,通过XRD表征确定其具有AlPO-5微孔分子筛的晶体结构。不同合成条件对V-AlPO5分子筛的催化活性有一定影响,优化合成条件下制备的V-AlPO5分子筛,在以过氧化氢为氧化剂的苯羟基化制苯酚反应中表现出较佳的催化活性。反应温度55 ℃,乙腈6 mL,苯10 mmol,质量分数35%过氧化氢15 mmol,氧化剂用量0.2 g,共还原剂抗坏血酸0.2 g,反应24 h,苯酚收率可达16.1%,选择性为86.8%。     

FeZSM-5/N2O催化氧化苯制苯酚

苯一步氧化制苯酚，是有机物氧化合成中富有挑战性的研究课题之一。该文着重论述了在FeZSM-5及其一系列沸石催化剂上，应用氧化亚氮作为氧化剂使苯直接氧化制苯酚的研究进展。这一系列催化剂体系的特殊之处在于通过氧化亚氮在沸石分子筛上的分解获得具有催化活性的a－氧。详细讨论了在沸石分子筛上形成特殊结构的铁氧化物作为催化活性中心这一观点。由于这种催化体系对苯直接氧化制苯酚的反应有着很高的选择性，因此，这种比较经济和安全的制备苯酚的方法引起了人们的广泛关注。     

纳米磷钼钒杂多酸盐催化苯羟基化合成苯酚

纳米磷钼钒杂多酸盐催化苯羟基化合成苯酚;苯; 羟基化; 苯酚; 纳米杂多化合物     

苯直接一步氧化合成苯酚

苯直接一步氧化合成苯酚是开辟苯酚合成路线具有挑战性的热点课题之一.近年来研究和开发了以N2O、H2O2和O23种不同氧化剂体系为核心和主流的苯氧化合成苯酚路线.本文详细综述了目前3种不同氧化体系的研究进展和趋势,分析了各种合成路线的特点和工业应用前景.以N2O为氧化剂合成苯酚路线,技术趋于成熟,但N2O来源受限而影响其经济性和推广应用;以H2O2为氧化剂合成苯酚路线,是环境友好过程,有开发潜力,但技术还很不成熟,而且也因H2O2价格昂贵带来了经济成本问题;以O2为氧化剂、氢气为还原剂体系合成苯酚路线,是环境清洁可持续发展制备路线,具有很好的开发潜力,此外无机膜催化合成苯酚路线也更具吸引力.     

Direct Oxidation of Benzene to Phenol by Dioxygen over Nano-vanadium Oxide

Reducing regents, such as ascorbic acid, are needed for vanadium‐containing catalysts to catalyze the direct oxidation of benzene to phenol by dioxygen. Quadrivalent vanadium species, reduced from quinquevalent vanadium species, can activate dioxygen to produce active oxygen species, which is important for the reaction. The key step is to prepare more V⁴⁺‐containing catalysts. Here, VO_X‐C₁₆‐A was prepared in an acidic medium to produce more V⁴⁺ species. The results of XPS and XRD studies confirmed that the vanadium species in VO_X‐C₁₆‐A was mainly V⁴⁺ ions. The results of XRD and electron diffraction patterns revealed that VO_X‐C₁₆‐A consisted of tetragonal VO₂ and monoclinic VO₂. Morphology observations display that the VO_X‐C₁₆‐A is made of nanorod. Investigations into the performances of the catalysts showed that VO_X‐C₁₆‐A was reusable, producing a 1.9% conversion of benzene without reducing agent.     

Toluene Alkylation to Selective Formation of p-Xylene over Co-Crystalline ZSM-12/ZSM-5 Catalyst

The alkylation of toluene with methanol to selective formation of p-xylene has been systematically studied. ZSM-12 (MTW)/ZSM-5 co-crystalline zeolite in 40:60 proportions have been synthesized by the same molar gel composition, but at different temperatures and periods than that of ZSM-12 and ZSM-5, separately. All the prepared samples are characterized by XRD, SEM, BET, and XRF. The activity of toluene alkylation was investigated with a mixture of toluene and methanol as a feed over the ZSM-12, ZSM-12/ZSM-5 co-crystalline, ZSM-5, and physical mixture of ZSM-12/ZSM-5. Prom characterization, it is observed that the ZSM-12/ZSM-5 co-crystalline material is different from that of ZSM-12, ZSM-5, and their physical mixture. Further, the ZSM-12/ZSM-5 co-crystalline zeolite produces the highest content of xylene and has better selectivity for p-xylene than ZSM-12, ZSM-5, and their physical mixture.     

海洋真菌对苯和甲苯的降解诱导黄烷酮的羟基化转化

真菌在各种氧化酶的作用下能将苯环类化合物转化降解,但转化降解过程中诱发的高活性酶的应用仍未见报道。本文研究海洋真菌Pseudallescheria boydii和Trichoderma erinaceum在添加苯和甲苯的培养条件下,诱导黄烷酮向4'-羟基黄烷酮的转化。结果表明,2种真菌对苯和甲苯有强耐受力,其降解过程中诱导的氧化酶对黄烷酮的羟基化具有高度的区域选择性,即发生4'-羟基化反应,而且转化率最高可达到82%,在酶促进的反应领域具有潜在的应用价值。     

Recent Advances in the Heterogeneous Photocatalytic Hydroxylation of Benzene to Phenol

Phenol is an important chemical material that is widely used in industry. Currently, phenol is dominantly produced by the well-known three-step cumene process, which suffers from severe drawbacks. Therefore, developing a green, sustainable, and economical strategy for the production of phenol directly from benzene is urgently needed. In recent years, the photocatalytic hydroxylation of benzene to phenol, which is economically feasible and could be performed under mild conditions, has attracted more attention, and development of highly efficient photocatalyst would be a key issue in this field. In this review, we systematically introduce the recent achievements of photocatalytic hydroxylation of benzene to phenol from 2015 to mid-2022, and various heterogeneous photocatalysts are comprehensively reviewed, including semiconductors, polyoxometalates (POMs), graphitic carbon nitride (g-C₃N₄), metal–organic frameworks (MOFs), carbon materials, and some other types of photocatalysts. Much effort is focused on the physical and chemical approaches for modification of these photocatalysts. The challenges and future promising directions for further enhancing the catalytic performances in photocatalytic hydroxylation of benzene are discussed in the end.     

杂原子ZSM－5分子筛催化剂上C_3H_6催化还原NO反应的研究

杂原子ＺＳＭ－５分子筛催化剂上Ｃ_３Ｈ_６催化还原ＮＯ反应的研究张文祥，贾明君，张春雷，吴通好，敖雪桔（吉林大学化学系，长春，１３００２３）（齐齐哈尔环境监测中心站）关键词杂原子分子筛，一氧化氮，催化还原ＮＯｘ对环境的危害已引起了人们的广泛重视。自Ｉｗ...     

HZSM-5分子筛催化剂在催化苯氧化合成苯酚反应中的积炭和失活行为

 在固定床反应器中进行了HZSM-5分子筛催化剂催化苯氧化生成苯酚时的积炭和失活实验,催化剂经高温水蒸气处理,反应条件为: 9.7%N2O-90.3%N2混合气流速115 ml/min,苯流速6 g/h,反应温度400 ℃. 采用TG,吸附吡啶的IR谱,13C NMR和低温N2吸附法对催化剂进行了表征,并用连续流动吸附法测定催化剂上正己烷和环己烷的吸附量. 结果表明,苯氧化生成苯酚的反应过程中,催化剂表面积炭导致分子筛微孔孔口堵塞是造成催化剂失活的主要原因. 与其他有机物在ZSM-5上的积炭相似,B酸中心是积炭的活性中心. 积炭物种主要为带有烷基的芳烃和多环芳烃,同时含有少量带有羟基的多环芳烃,这可能是由在L酸中心上生成的苯酚进一步氧化、脱氢和聚合形成的.     

苯在[K.Ti]ZSM-5上由H2O2氧化制苯酚的研究

由 HZSM-5与 K2 Ti F6 水热法同晶取代制备 [K.Ti]/ ZSM-5 ,并用 XRD、SEM、IR给予表征 ,其在等摩尔的苯、苯酚、H2 O2 液相反应体系中 ,常温下表现出较高催化活性 ,苯转化率达 83 % (1 6h) ,选择性≥ 98% ,苯酚产率为 2 .4m M/ h· Cat(g) ,同时探讨了有关影响因素。     

Cu-HZSM-5上氯苯气相羟化反应及催化剂失活

研究了Cu-HZSM-5催化剂上的氯苯气相羟化合成苯酚反应及催化剂的失活情况.发现在773 K和水/氯苯体积比为3的反应条件下,1.6%Cu-HZSM-5催化剂上氯苯转化率高达82.4%,苯酚选择性为98.2%,但催化性能随着反应的进行有逐渐下降的趋势.采用X射线衍射、氮气静态吸附、X射线能谱和吡啶吸附红外光谱等手段对反应前后的催化剂进行了表征.结果表明,铜的流失、HZSM-5分子筛骨架脱铝、晶格塌陷和积炭是导致催化剂失活的主要原因.     

Ozone-Assisted Catalysis of Toluene with Layered ZSM-5 and Ag/ZSM-5 Zeolites

This paper presents a new type of ozone-assisted catalysis for toluene decomposition. The different catalytic activities of ZSM-5 and Ag/ZSM-5 were incorporated into a layered catalyst with a tandem configuration. Instead of increasing the amount of metal catalyst, the layered catalyst was formed, which had an equal amount of bare ZSM-5 and Ag/ZSM-5 and could achieve both high toluene conversion and CO₂ selectivity concurrently. The properties of each catalyst were evaluated with respect to toluene conversion, formation of intermediates, CO₂ selectivity and ozone demand factor. The bare ZSM-5 exhibited higher toluene conversion than the Ag/ZSM-5, while its activity toward deep oxidation was limited. However, the Ag/ZSM-5 was found to be effective for the deep oxidation of reaction intermediates (HCOOH and CO). Separate oxidation tests with HCOOH and CO revealed that the ZSM-5-supported Ag nanoparticles could oxidize the HCOOH and CO in the absence of ozone, which was not possible with the bare ZSM-5. Plausible pathways for the oxidation of toluene with O₃ over ZSM-5 and Ag/ZSM-5 were proposed based on the experimental evidence.     

ZSM-5分子筛催化苯与甲醇烷基化反应研究进展

我们综述了近年来苯和甲醇烷基化反应研究取得的进展.重点从ZSM-5催化剂的Si/Al、晶粒尺寸、改性等方面介绍了苯和甲醇烷基化催化剂的研究进展,总结并展望了苯和甲醇烷基化反应的研究方向,为ZSM-5分子筛催化剂的改性和苯-甲醇烷基化反应工艺创新提供参考.     

苯直接羟基化制苯酚研究进展*

综述了苯直接羟基化制苯酚的几种催化反应,包括阳极氧化法、N₂O氧化法、H₂O₂氧化法、O₂直接氧化法,这些反应均具有良好的原子经济性和环境效益.同时重点介绍了相关的催化剂及其活性中心,探讨了这些新型方法的工业应用前景.     

高硅ZSM-5分子筛和二次合成Ti-ZSM-5分子筛的结构

运用度角旋转（MAS）和交叉极化（CP）等核磁共振波谱和红外光谱技术，分别对采用不同模板剂制备的高硅ZSM－5分子筛和以此为母体，经气固同晶取代法得到Ti－ZSM－5分子筛的结构特性进行了研究．结果表明：在水热法合成高硅ZSM-5分子筛过程中，模板剂明显制约着所制得的分子筛的结构特性．通过选用合适的模板剂，可直接获得具有正交晶系结构的高硅ZSM－5分子筛．在随后的气固相同晶取代过程中，钛原子通过占据分子筛骨架中的缺陷位进入骨架，形成具有一定Ti／Si比例的钛硅分子筛（Ti－ZSM－5）。骨架结构中缺陷位的含量直接影响分子筛的载钛量。     

Nanostructure Copper-exchanged ZSM-5 Catalytic Activity for Conversion of Volatile Organic Compounds (Toluene and Ethyl Acetate)

Gas phase catalytic oxidation of ethyl acetate and toluene was examined over copper modified ZSM‐5 catalysts under atmospheric pressure. Nanostructure of ZSM‐5 was characterized by XRD, SEM and TEM techniques. Elemental composition of ZSM‐5 was determined using EDX, ICP‐AES and XPS techniques. Results of catalytic studies showed better catalytic activity of Cu‐ZSM‐5 catalysts than those of parent ZSM‐5 and HZSM‐5, which revealed catalytic role of copper ions in the Cu‐ZSM‐5 catalysts. Effects of some parameters over catalytic conversion of these compounds were also studied. Ethyl acetate showed more reactivity than toluene over the Cu‐ZSM‐5 catalysts. Furthermore, the catalytic activity of Cu‐ZSM‐5 catalysts increased with increasing the copper loadings. The conversion behavior of a binary mixture of ethyl acetate and toluene was different from that of a single form. A promotive and inhibitive behavior was observed for conversion of ethyl acetate and toluene in the binary mixture, respectively. Water vapor as co‐feed had an inhibitive effect on conversion of organic compounds over the Cu‐ZSM‐5 catalysts.     

Selective Production of Phenol on Bifunctional,Hierarchical ZSM-5 Zeolites

Mono- and bimetallic Ni-, Ru- and Pt-modified hierarchical ZSM-5 materials were prepared by impregnation technique and characterized by X-ray diffraction (XRD), N₂ physisorption, temperature-programmed reduction (TPR–TGA), ATR–FTIR and solid state NMR spectroscopy. Formation of finely dispersed nickel, ruthenium and platinum species was observed on the bimetallic catalysts. It was found that the peculiarity of the used zeolite structure and the modification procedure determine the type of formed metal oxides and their dispersion and reducibility. The samples’ acidity was studied via FTIR spectroscopy of adsorbed pyridine. The changes in the zeolite structure were studied via solid-state NMR spectroscopy. The catalysts were investigated in a gas-phase hydrodeoxygenation, transalkylation and dealkylation reaction of model lignin derivative molecules for phenol production.