Rh—Mo—K／Al2O3催化剂的CO加氢合成低碳醇性能

本文研究了硫化态和还原态Ｒｈ－Ｍｏ－Ｋ／Ａｌ２Ｏ３催化剂上ＣＯ加氢合成低碳醇的反应性能，考察了不同铑负载量、钾助剂、合成气组成和反应条件（温度、压力和空速）对合成醇性能的影响及催化剂的反应稳定性。发现硫化样品较之还原态样品具有更好的合成醇选择性，催化剂中添加铑后，生成醇活性和选择性大幅度提高。选择合适的反应温度、提高反应压力和空速、适当增加合成气Ｈ２／ＣＯ的比例可以获得较好的合成醇反应性能。     

一氧化碳加氢合成低碳燃料醇催化剂的研究

以甲醇为主(～75%),异丁醇为辅(～15%)的低碳混合醇称为低碳燃料醇,它与汽油有良好的掺合能,可以掺入汽油作为代用燃料。本工作目的是在较缓和条件下研制合成低碳燃料醇催化剂,进行催化剂评价试验,考察其反应特性,并进行1000小时稳定性试验。1.实验方法催化剂评价试验在固定床反应装置上进行。反应管为φ15×480mm。催化剂20—30     

流化床中苯催化氧化制顺酐——催化剂的研制及应用

本文叙述流化床中苯催化氧化制顺丁烯二酸酐所用的V-P-Mo/硅胶催化剂之最佳组份及制备方法。在Φ30mm的反应器上,考察了反应温度、苯浓度和空间速度对其催化性能的影响。工业放大制备的催化剂之性能基本与实验室制备者相符。当用于Φ1000mm反应器中时,经3600小时运转,活性稳定,顺酐收率保持在55—58%之间。     

Fe-Mn超细粒子催化剂对FT合成反应的研究Ⅰ.反应条件的影响

在内循环无梯度反应器（Ｂｅｒｔｙ反应器）中研究了Ｆｅ－Ｍｎ超细粒子催化剂费托合成反应的规律。详细考察了温度、压力、空速对ＦＴ反应性能的影响。结果表明,反应条件对催化剂低碳烃及ＣＯ２的选择性等都有一定的影响,在考察的时间范围（１２００ｈ）内,即使在较宽的操作条件下,催化剂仍具有良好的活性和稳定性。还发现随着低碳烯烃选择性的提高,低碳烃的烯烷比下降不明显。     

精制煤液化中油加氢裂化制取喷气燃料的研究

在实验室固定床反应装置上,选用Mo-Ni-P/Si-Al工业催化剂,对精煤液化中油进行了加氢裂化制取喷气燃料的实验。考察了反应温度、空速对芳烃加氢转化及产品馏分分布的影响。通过加氢裂化,降低了油品芳烃含量,提高了喷气燃料馏分的收率。在总压为15MPa,反应温度为350—360℃,空速为0.8—1.0h~(-1)条件下,获得了芳烃含量低于10w%的低结晶点的优质喷气燃料产品。并对煤液化中油制取的喷气燃料的组成和性质进行了分析和评价。     

助剂和原料气中CO2浓度对CuFeZr催化剂用于合成气制混合醇的影响

考察了不同助剂（Mn、Zn、Co）对CuFeZr催化剂用于合成气制混合醇的影响。借助BET、XRD、H₂-TPR等对其物化性质进行了表征,结果表明,加入助剂可减小颗粒粒径并且增强对CO的吸附能力以及催化剂表面碱性,其中,加入Zn可以增强CuFe间的相互作用,改善CuFeZr催化剂的还原性质,提高对CO的吸附能力,以及提供最强的表面碱性。用固定床反应器对催化剂的反应性能进行了评价,反应结果表明,加入Zn可以显著提高CuFeZr催化剂用于合成气制混合醇的反应活性及醇选择性,使醇时空收率从0.026 g/（g_cat·h）提高至0.071 g/（g_cat·h）。由于循环条件下,反应产物CO₂同时也是原料气的组成成分,进一步地探究了原料气中CO₂浓度对催化剂反应性能的影响。结果表明,加入CO₂可提高CO转化率和醇以及烃的收率,但阻碍链增长反应并使得产物烯烷比降低。其中,在所考察浓度范围内,原料气中含有2.5%的CO₂最有利于醇和烃的生成尤其是低碳醇和低碳烃的生成。     

F-T合成沉淀铁系催化剂的原位再生(英文)

Ｆ－Ｔ合成沉淀铁系催化剂在３ ０００小时工业单管模试反应器中进行了三次原位再生试验。用自产的Ｃ６—Ｃ１１馏分油在接近其临界点的条件下对催化剂进行处理,然后用Ｈ２或合成气还原。经过上述再生处理,催化剂床层压降从１．０ ＭＰａ降至０．１ＭＰａ,催化剂反应性能同时得到恢复。还讨论了导致催化剂失活和催化剂床层压降增加的原因。     

甲醇在电结晶银催化剂上催化氧化制浓甲醛

研究了用电结晶银催化剂由甲醇催化氧化脱氢直接制备浓甲醛的最佳反应条件。结果表明,当反应温度为640℃,氧醇分子比为0.505,惰性气体量为0.6升/分(其中含N_297—95％,CO_23—5％)时,制得的浓甲醛的重量浓度大于50％,醇含量小于3％,符合用于制备聚甲醛的浓甲醛质量要求;在该反应条件下,甲醇的转化率为97.6％,甲醛产率为87.1％,反应选择性为89.2％,空速为43300小时~(-1),时空产率为0.22克分子甲醛/克催化剂·小时。根据热力学和宏观动力学的观点解释了所得的主要实验结果。     

流化床反应器中Ni/γ-Al2O3催化剂上甲烷部分氧化制合成气

催化甲烷部分氧化(POM)制合成气已成为替代水蒸气重整最有希望的工艺过程之一[1]. 该过程是个温和的放热反应,反应速度非常快,在高空速下可实现高甲烷转化,并且制得的合成气V(H2)/V(CO)=2, 可直接用于合成甲醇及F-T合成烃类、合成二甲醚等后续工业过程. 到目前为止,大部分POM的研究工作在固定床反应器中进行[2～4]. 由于反应速度极快,导致催化剂表面存在热点[2,5], 不仅影响实验的准确性[6,7], 而且工业应用困难. 热点的存在还会导致活性组分Ni的烧结和流失. 在固定床反应器中,催化剂积炭也是导致其活性下降的重要原因[8,9]. Bharadwaj等[10]发现,流化床反应器Rh和Ni催化剂上甲烷转化率高达90%, 反应后催化剂未发现积炭. Santos等[11]曾报道采用流化床催化剂床层几乎可以实现等温分布,而且甲烷转化率接近热力学平衡值, 反应10 h后催化剂表面积炭量仅为0.6%. 本文采用流化床反应器考察了不同反应条件下Ni/γ-Al2O3催化剂上甲烷部分氧化的反应性能,同时对催化剂积炭及稳定性作了初步研究.     

Ni/ZrO2催化剂上甲烷水蒸气重整反应的研究

研究了Ni/ZrO2催化剂对甲烷水蒸气重整制合成气的反应性能。考察了催化剂的还原温度、载体焙烧温度以及反应温度、原料配比和空速等对催化剂性能的影响。利用XRD、TEM、XPS等手段对催化剂的织构形貌进行了表征。研究表明，Ni/ZrO2催化剂用于甲烷水蒸气重整制合成气不仅具有较高的活性，也具有较好的稳定性。水蒸气比增加，CH4转化率增大、CO选择性下降。CH4转化率及CO选择性均随空速增大而下降。使用10%Ni/ZrO2催化剂，在650 ℃、空速1.984×104 h－1、原料气配比H2O∶CH4∶N2=2∶1∶2.67的条件下，获得CH4转化率85%、CO选择性70%的结果。     

Thermal behaviour of some sugar alcohols

The glass transition of isomalt and its components, the enthalpy of solution (crystalline state, glassy state) and the enthalpy of melting are reported. From the measured data (solution enthalpy, enthalpy of fusion and heat capacities) a cycle like the BORN-HABER cycle can be constructed. It is possible to calculate the amounts of amorphous isomalt from measured solution enthalpies; however, the values obtained do not agree with those provided by X-ray powder diffraction studies.This study was supported by Südzucker AG, Mannheim/Ochsenfurt. We thank Dr. M. Kunz and G. Witte of Südzucker AG for discussions.     

Ruthenium-catalyzed propargylic substitution reactions of propargylic alcohols with oxygen-, nitrogen-, and phosphorus-centered nucleophiles

The scope and limitations of the ruthenium-catalyzed propargylic substitution reaction of propargylic alcohols with heteroatom-centered nucleophiles are presented. Oxygen-, nitrogen-, and phosphorus-centered nucleophiles such as alcohols, amines, amides, and phosphine oxide are available for this catalytic reaction. Only the thiolate-bridged diruthenium complexes can work as catalysts for this reaction. Results of some stoichiometric and catalytic reactions indicate that the catalytic propargylic substitution reaction proceeds via an allenylidene complex formed in situ, whereby the attack of nucleophiles to the allenylidene C(gamma) atom is a key step. Investigation of the relative rate constants for the reaction of propargylic alcohols with several para-substituted anilines reveals that the attack of anilines on the allenylidene C(gamma) atom is not involved in the rate-determining step and rather the acidity of conjugated anilines of an alkynyl complex, which is formed after the attack of aniline on the C(gamma) atom, is considered to be the most important factor to determine the rate of this catalytic reaction. The key point to promote this catalytic reaction by using the thiolate-bridged diruthenium complexes is considered to be the ease of the ligand exchange step between a vinylidene ligand on the diruthenium complexes and another propargylic alcohol in the catalytic cycle. The reason why only the thiolate-bridged diruthenium complexes promote the ligand exchange step more easily with respect to other monoruthenium complexes in this catalytic reaction should be that one Ru moiety, which is not involved in the allenylidene formation, works as an electron pool or a mobile ligand to another Ru site. The catalytic procedure presented here provides a versatile, direct, and one-step method for propargylic substitution of propargylic alcohols in contrast to the so far well-known stoichiometric and stepwise Nicholas reaction.     

Pd nanoparticles as catalysts for green and sustainable oxidation of functionalized alcohols in aqueous media

The previously described catalyst system for the aerobic oxidation of alcohols, comprising palladium(II) acetate in combination with neocuproine in a 1:1 mixture of water and a water-miscible cosolvent such as ethylene carbonate or dimethylsulfoxide, was shown to involve palladium nanoparticles as the active catalyst. The latter are formed in situ or can be preformed by reduction of the palladium-neocuproine complex with hydrogen and they are stabilized by both the neocuproine ligand and the cosolvent. This catalyst system was successfully used for the selective aerobic oxidation of the steroidal secondary alcohols, nandrolone and 5α-pregnan-3α-ol-20-one, to the corresponding ketones.     

Tf-based sulfamide-amine alcohol-catalyzed enantioselective alkynylation of aldehydes

A series of new chiral Tf-based sulfamide-amine alcohols (Tf-based SAA) were synthesized from natural chiral (−)-ephedrine and aziridines derived from commercially available chiral amino alcohols. Among these ligands, 3a was found to be more effective for the addition reaction of alkynylzinc to aromatic aldehyes at room temperature without using other kinds of metal species, providing 81-92% ee and up to 99% yields.     

硫化钼系催化剂上低碳醇的分布规律

对低碳混合醇的合成机理,有些学者曾提出了一些假说,例如Graves的构想以及Smith和Anderson的模型等。这些假说有的已被实验所验证,成功地描述了催化剂上产物的分布情况,但对于硫化钼系催化剂,由于发展较晚,尚未见到系统的合成机理的研究报道。Schulz-Flory方程(简称S-F方程)是用来解释费托合成烃类产物的分布规律。我们考察了硫化钼系催化剂上醇类产物分布的特点,得出了醇类分布符合S-F分布规律,并推出了适合于醇分布的S-F方程。     

Detailed studies on the reduction of aliphatic 3-, 4-, 6-, and 13-oximino esters: Synthesis of novel isomeric amino esters,oximino alcohols,and amino alcohols

The preparation of novel 3-, 4-, 6-, and 13-amino-tetradecanoic acid methyl esters (2a–d) obtained by the reduction of 3-, 4-, 6-, and 13-oximino-tetradecanoic acid methyl esters (1a–d), was investigated. Oximino esters were reduced to afford the corresponding amino esters using NaBH₄–ZrCl₄ reducing system with good yields (58–82%). However, the reduction of oximino esters with LiAlH₄ and BH₃. Tetrahydrofuran gave the corresponding novel 3-, 4-, 6-, and 13-oximino alcohols (3a–d), and 3-, 4-, 6-, and 13-amino alcohols (4a–d) respectively with good chemical yields.     

Palladium-catalyzed stereoselective hydrostannation of substituted propargyl alcohols with trineophyltin hydride

This paper reports results obtained in a study on the palladium-catalyzed hydrostannation of substituted propargyl alcohols with the bulky trineophyltin hydride (1). The reaction of 1 with 10 propargyl alcohols containing one up to three substituents, was carried out in THF at room temperature leading to the corresponding allylstannanes following in all cases a syn addition stereochemistry. These additions took place in good to excellent yields and, mostly, with a high degree of stereoselectivity. The results obtained suggest that the observed α/β regioselectivity might be ascribed to the steric bulk of the proximal substituents rather than to electronic effects. Full ¹H-, ¹³C-, and ¹¹⁹Sn NMR characteristics are included.