甘油催化氧化合成二羟基丙酮研究进展

对甘油选择性催化氧化转化为二羟基丙酮的研究进行综述,介绍了负载型催化剂在不同条件下对产物选择性和反应物转化率的影响,以及催化剂的作用机理。阐述了甘油催化氧化存在的问题以及发展前景。从均相到非均相催化,从单金属到双金属负载催化,从金属到非金属催化,甘油氧化反应的研究不断在完善。研究发现用Bi改性的Pt负载催化剂可以有效地将甘油选择性催化氧化为二羟基丙酮,在最优条件下,可获得较高的甘油转化率和二羟基丙酮选择性,但催化剂稳定性较差,有待进一步提高。杂多酸催化剂以及非金属催化剂也存在稳定性差的问题。指出改善催化剂的稳定性将是未来研究的主要方向。     

助剂对V基催化剂甲醇-乙醇一步合成异丁醛的影响

在柠檬酸存在条件下,采用偏钒酸铵、硝酸钙、硝酸铁和硝酸镁为原料,通过沉淀法合成了V-Ca、V-Mg和V-Fe氧化物催化剂。同时,对比研究了V-Ca、V-Mg和V-Fe氧化物催化剂催化甲醇-乙醇一步合成异丁醛性能。结果表明,与加入Ca和Mg相比,加入Fe可以促进异丁醛的合成。在相同实验条件下,采用V-Ca和V-Mg催化剂时,乙醇转化率分别为48.7%和55.1%,异丁醛选择性分别为13.7%和13.5%,而采用V-Fe催化剂,乙醇转化率和异丁醛选择性分别为86.7%和32.4%。BET和SEM表征结果显示,Ca、Mg和Fe的加入影响催化剂的表面积和形貌。     

Zn-Fe复合氧化物催化生物乙醇制丙酮的研究

生物乙醇在制备高附加值化学品方面有着广阔的发展前景。本研究用共沉淀法制备一系列不同Zn-Fe摩尔配比(4∶1、3∶2、1∶1、2∶3、1∶9)的Zn-Fe复合氧化物催化剂,并对其催化生物乙醇转化制丙酮反应进行活性评价。结果发现,Zn∶Fe=4∶1的催化剂效果最好,催化剂最佳反应温度在450℃,乙醇转化率96%,丙酮的选择性可达56%,X-射线衍射结果研究表明Zn-Fe催化剂主要由Zn O、Zn Fe2O4尖晶石相组成。     

Ni_2P/SiO_2催化剂制备及其乙酸加氢制乙醇催化性能评价

通过等体积浸渍和N_2气流中热处理过程制备了系列氧化硅负载过渡金属磷化物催化剂,经乙酸加氢制乙醇反应实验和动力学分析评价催化剂性能。研究结果表明,随着反应温度从280℃升高到340℃,乙酸转化率和乙醇选择性均逐渐提高。随着催化剂制备的P/Ni摩尔比从2:1增大到4:1,催化剂活性和乙醇选择性均先增大后减小,P/Ni摩尔比为3:1催化剂性能较佳。250℃热处理制备催化剂的催化性能优于200℃及300℃。Ni_2P/SiO_2催化剂活性和乙醇选择性均高于Co_2P/SiO_2催化剂。用次磷酸钠作为磷补充源制备催化剂的性能优于次磷酸钾。采用较佳条件下制备的Ni_2P/SiO_2催化剂,在温度340℃、压力2.0 MPa、氢酸进料量比10:1、质量空速0.4 h~(-1)条件下进行乙酸加氢反应,乙酸转化率为100%,乙醇选择性达到74.56%,并且适当升高反应温度会进一步提高乙醇选择性。     

La_(1-x)Cu_x MnO_3/HZSM-5催化乙醇制正丁醛

采用改进的柠檬酸络合法制备La_(1-x)Cu_xMnO_3系列复合氧化物,研磨法制备La_(0.8)Cu_(0.2)MnO_3/HZSM-5催化剂,用X射线粉末衍射进行物相分析,考察无氧条件下对乙醇制正丁醛的催化活性。结果表明,在反应温度500℃和空速3 184 h~(-1)的条件下,La_(1-x)Cu_xMnO_3系列复合氧化物中La_(0.8)Cu_(0.2)MnO_3催化活性较高,乙醇转化率为47.53%,正丁醛选择性为37.72%;对于La_(0.8)Cu_(0.2)MnO_3/HZSM-5催化剂,当HZSM-5的质量分数为14%时,催化效果最好,乙醇转化率为60.42%,正丁醛选择性为46.81%。     

Ni2P/SiO2催化剂制备及其乙酸加氢制乙醇催化性能评价

通过等体积浸渍和N₂气流中热处理过程制备了系列氧化硅负载过渡金属磷化物催化剂,经乙酸加氢制乙醇反应实验和动力学分析评价催化剂性能。研究结果表明,随着反应温度从280℃升高到340℃,乙酸转化率和乙醇选择性均逐渐提高。随着催化剂制备的P/Ni摩尔比从2：1增大到4：1,催化剂活性和乙醇选择性均先增大后减小,P/Ni摩尔比为3：1催化剂性能较佳。250℃热处理制备催化剂的催化性能优于200℃及300℃。Ni₂P/SiO₂催化剂活性和乙醇选择性均高于Co₂P/SiO₂催化剂。用次磷酸钠作为磷补充源制备催化剂的性能优于次磷酸钾。采用较佳条件下制备的Ni₂P/SiO₂催化剂,在温度340℃、压力2.0 MPa、氢酸进料量比10：1、质量空速0.4 h^-1条件下进行乙酸加氢反应,乙酸转化率为100%,乙醇选择性达到74.56%,并且适当升高反应温度会进一步提高乙醇选择性。     

MgO复合载体负载Ni催化乙醇水蒸气重整制氢

将稀土化合物CeO_2和La_2O_2CO_3分别与MgO载体复合负载Ni,制备Ni/MgO-La_2O_2CO_3(NML)和Ni/MgO-CeO_2(NMC)催化剂,用于催化乙醇水蒸气重整制氢。通过XRD研究负载催化的晶相,程序升温还原(TPR)对催化剂的综合性能进行分析。结果表明:稀土化合物复合的NMC,NML能明显提高Ni/MgO(NM)的低温乙醇转化率,350℃时,NM的乙醇转化率为78.3%,而此时NML,NMC的乙醇转化率却已接近100%,400—500℃范围内,NMC和NML明显提高了NM的H_2选择性,CO_2选择性也有所提高,同时降低了NM的CO,CH_4选择性,其中NMC的H_2选择性高于NML,而CO_2,CO,CH_4选择性却均低于NML,综合考虑乙醇转化率,NMC和NML能明显提高NM的综合催化性能,其中MgO-CeO_2复合载体负载Ni(NMC)对乙醇重整制氢的催化效果最好。     

二氧化碳和乙醇直接合成碳酸二乙酯的研究

为了提高碳酸二乙酯的转化率与选择性,对二氧化碳和乙醇直接合成碳酸二乙酯的过程进行了研究。确定了较优的催化剂为ZrO2和3A分子筛作为混合催化剂。对催化剂的制备工艺进行了优化:采用正相沉淀方式,沉淀pH值为9,焙烧温度为600℃时制备的ZrO2按质量比为5∶2的比例与3A分子筛进行物理混合后催化效果最佳。在乙醇和二氧化碳的进料比为514/225 mmol下,碳酸二乙酯的产量可以达到0.054 3 mmol,选择性在60%以上。在该催化体系中,加入脱水剂乙烯、环氧丙烷和环氧丁烷均无法达到高效提高反应产率的效果。     

蒎烷催化异构制取二氢月桂烯

本文研究在复相催化剂的作用下,以来源于松节油的α-蒎烯作原料,通过催化加氢得到蒎烷,再催化异构制取香精的原材料——二氢月桂烯。文中以微型固定床反应器考察并筛选出四种有开发价值的氧化物催化剂;;研究了反应温度,原料空速对催化反应转化率及选择性的影响。还讨论了蒎烷催化异构化反应的机理。     

流化床中甲烷芳构化过程

在石英流化床反应器中研究了无氧条件下甲烷直接催化转化制备芳烃的过程.发现催化剂的诱导期长短、甲烷的总转化率与温度、甲烷分压及甲烷空速相关.在973 K下,液体产品中苯的选择性与萘的选择性随着催化剂的失活呈现不同的变化趋势.所得主要技术指标（甲烷转化率、苯的收率与选择性等）与固定床微型反应器中的结果相近.还研究了催化剂上的积炭对甲烷转化率、催化剂失活的影响,为将来的进一步研究提供了基础.     

Comparison of different heterogeneous catalysts and different alcohols for the esterification reaction of oleic acid

Oils with high amount of free fatty acid (FFA) are becoming one of the most promising alternatives to produced biodiesel; due, principally, to it low cost. However, because of the presence of FFA, the conventional basic homogenous catalyst should not be used with the aim to avoid the production of soaps.In this work, different catalysts, such as solid resins, zeolite and enzymes, as well as different alcohols: ethanol anhydrous, ethanol 96°, 1-propanol, 2-propanol and butanol, were tested for the direct esterification reaction of pure oleic acid.The influence of several variables, such as alcohol’s carbon chain length, the presence of water, which has a negative effect on the final conversion shifting the final conversion to a lower level, and the location of the OH group were studied.The enzymatic catalyst, Lipozyme CALB, turned out to be the best one, achieving a final conversion of 98% after three days reaction.     

Butanol production in a sugarcane biorefinery using ethanol as feedstock. Part I: Integration to a first generation sugarcane distillery

Butanol production from renewable resources has been increasingly investigated over the past decade, mostly for its use as a liquid biofuel for road transportation, since its energy density is higher than that of ethanol and it may be used in gasoline driven engines with practically no changes, but also for use as a feedstock in the chemical industry. Most of the research concerning butanol production focuses on the ABE process (fermentation of sugars into a mixture of acetone, butanol and ethanol), which has several drawbacks regarding microorganism performance and product inhibition. An alternative to ABE fermentation, ethanol catalytic conversion to butanol can produce a higher quality product with less retrofitting than ABE in existing ethanol producing facilities. There are different types of catalysts for the chemical conversion of ethanol to butanol being developed in laboratory scale, but their actual use in a sugarcane processing plant has never before been assessed. Butanol production from ethanol in a sugarcane biorefinery, using data from the literature, was assessed in this study; different technological alternatives (catalytic routes) were evaluated through computer simulation in Aspen Plus (including production of electricity, sugar, ethanol and other products) and economic and environmental impacts were assessed. Results indicate that vapor-phase catalysis presents higher potential for industrial implementation, and commercialization of butanol for use as a chemical feedstock has an economic performance similar to that of current, optimized first generation sugarcane distilleries, but can potentially contribute to cost reduction that will allow commercialization of butanol as a fuel in the future.     

适用于丙烯二聚反应非均相催化剂的研究进展

丙烯二聚反应是生产4-甲基-1-戊烯、1-己烯等端碳烯烃的重要手段,其产物可作为特种高分子材料单体、汽油添加剂和化工有机中间体,关键技术在于高效催化剂的开发。非均相催化剂相比于均相催化剂因易回收、对环境污染小等优点受到了学者们的广泛关注。本文综述了丙烯二聚非均相催化剂的研究进展,依据固体碱催化剂与固体酸催化剂在丙烯二聚反应中不同的反应机理,比较了两者各自的优缺点。回顾了固体碱催化剂的发展历程及工业化应用,并以碱金属钾为例总结了反应机理。详细介绍了固体酸催化剂中的固体磷酸催化剂、分子筛催化剂和负载型过渡金属催化剂。针对固体碱催化剂制备条件苛刻等问题,提出了改善催化装置的新思路;针对固体酸催化剂选择性不足的劣势,指出了应该进一步完善机理,并合理设计酸性载体与过渡金属相结合的催化剂。     

Baeyer–Villiger oxidation of cyclohexanone catalyzed by cordierite honeycomb washcoated with Mg–Sn–W composite oxides

In this work, a series of Mg–Sn–W oxide powder catalysts with different tungsten oxide contents(0, 15 wt% and 30 wt%) were prepared and washcoated on cordierite honeycomb monoliths to produce monolithic catalysts,which were tested for the Baeyer–Villiger oxidation of cyclohexanone. The obtained monolithic catalysts,which combined the advantages of both homogeneous and heterogeneous catalysts, showed high catalytic efficiency and overcame the problems of product separation that occurred in the homogeneous catalytic process.SEM and EDX tests showed that the catalytic coating, with a thickness of approximately 20 μm, was compact and homogeneous, and an enlarged BET surface area was indicated by N_2 adsorption–desorption compared with the bare cordierite honeycomb. The chemical properties on the catalytic surface of the powder and monolithic catalysts were characterized by XPS, which indicated the tin and tungsten on the catalysts exhibited their full oxide states and presented mainly as stannate and tungstate, as confirmed by XRD and FTIR characterizations.Moreover, the catalytic activity test indicated that the tungsten content of the catalysts played an important role in catalytic efficiency and that monolithic catalysts were produced without obvious catalytic activity loss compared with the corresponding powders.(M)W30, which exhibited excellent mechanical stability and maintained high activity after recycling three times, was the optimal catalyst, showing a high selectivity that exceeded 86%and a conversion above 64%. Therefore, the structured Mg–Sn–W oxide catalysts have great potential for application in practical production.     

离子液体催化丁醇与盐酸反应制备丁基氯

The catalytic performance of some quaternary ammonium salts for the liquid phase reaction of butanol and hydrochloric acid at different conditions was studied experimentally and compared with the traditional catalyst （ZnCl2）. The organic ammonium catalysts investigated include ionic liquids N-butyl-N-methyl imidazolium fluoborate （[BMIM][BF4]） and N-butyl-N-methylimidazolium chloride （[BMIM]Cl） as well as hydrochloric salts of N-methylimidazol （[HMIM]Cl）, pyridine （[HPy]Cl） and triethylamine （[HEt3N]Cl）. It is shown that the intrinsic catalytic performance of all organic ammonium salts except [HEt3N]Cl is slightly superior to ZnCl2, while the selectivity of butyl chloride is nearly at the same level around 96%. The conversion of butanol increases slightly with temperature and the catalyst amount added while the variation of selectivity is not obvious. Based on the recycle experiments, the ionic liquids as catalyst for the reaction of butanol and hydrochloric acid can be used more than 5 times, which suggests great potential of using ionic liquids as novel catalyst for such reactions.     

High selectivity of TaSiBEA zeolite catalysts in 1,3-butadiene production from ethanol and acetaldehyde mixture

New tantalum-silica based zeolite catalysts (TaSiBEA) were applied in this work for 1,3-butadiene production from ethanol. Tantalum incorporation into vacant T-atom sites of the SiBEA zeolites framework as mononuclear Ta(V) allowed preparing highly selective catalysts for ethanol/acetaldehyde mixture conversion into 1,3-butadiene, with selectivity to 1,3-butadiene of 80–90% at total conversion of the mixture of 45–30%. Effect of Ta content on activity of TaSiBEA zeolite catalysts and the ethanol/acetaldehyde molar ratio in selective production of 1,3-butadiene were demonstrated.     

杂多酸(盐)催化合成丙烯酸正丁酯的研究

对杂多酸（ 盐） 均相、非均相和固载型催化剂催化丙烯酸和正丁醇反应合成丙烯酸正丁酯进行了研究。实验结果表明：丙烯酸０－５ｍｏｌ、正丁醇０－５５ｍｏｌ、催化剂用量为丙烯酸质量的１－２％ 、反应温度为１３０℃时,丙烯酸的转化率和酯化反应的选择性都在９６％ 以上。非均相和固载型杂多酸（ 盐） 催化剂均可多次使用而活性没有明显下降。     

窄分布醇醚合成用催化剂的筛选与催化作用分析

讨论了酸、碱催化剂对窄分布醇醚合成反应的催化性能。从反应物转化率、醇醚产物选择性和醇醚分子量分布窄度几个方面综合考察了酸、碱类催化剂的优缺点,发现酸性催化剂的催化活性普遍较高,均在９５％以上,产物分子量分布较窄,ｎ＜５的产物占醇醚产物总质量的８５％左右,但生成的非醇醚类产物杂质较多,占反应产物质量的１４％以上;碱性催化剂的催化活性不一,其中活性较高的固体碱类镁铝复合金属氧化物（ＬＤＯ）与酸性催化剂活性相当,达９９．９％,且其产物纯净,非醇醚类产物仅占反应产物质量的１．２％,其醇醚产物分子量分布虽然宽于酸性催化剂,ｎ＜５的醇醚占醇醚产物质量的７７．２％,但明显窄于工业上普遍应用的均相催化剂ＫＯＨ（６６．８％）,是较有发展前景的催化剂。