甲烷二氧化碳重整制合成气的镍基催化剂性能Ⅱ.碱性助剂的作用

考察了碱性助剂Ｋ２Ｏ，Ｌｉ２Ｏ，ＭｇＯ，Ｌａ２Ｏ３与ＣｅＯ２对Ｎｉ／γ－Ａｌ２Ｏ３催化剂上ＣＨ４－ＣＯ２重整反应活性和抗积炭能力等方面的影响，结果表明，这些助剂对催化剂的抗积炭能力都有明显的改善作用，ＣＨ４－ＣＯ２重整活性不同温度范围内也有不同程度的提高，其中，ＭｇＯ，Ｌａ２Ｏ３和ＣｅＯ２助剂的作用明显，但与添加顺序有关，先浸Ｎｉ后浸Ｍｇ制备的催化剂有较高的ＣＨ４转化率，但抗积炭能力远不如先浸Ｍｇ     

负载型镍金属催化剂上甲烷与二氧化碳重整制合成气

报道了负载型Ｎｉ金属催化剂的表面特征和对ＣＨ４与ＣＯ２重整制合成气的催化性能，反应结果和ＴＰＲ，ＸＲＣ结果表明：Ｎｉ担载量为９．０％的催化剂具有最佳的反应性能，Ｎｉ组分以高散表面化合物形式存在，助剂对催化剂活性的影响随载体和添加方式的不同较大差异，其中少量ＭｇＯ，Ｌａ２Ｏ３对改善催化剂的稳定性和抗积碳能力有十分显著的效果，载体和制备方法对催化剂性能具有明显影响，其中浸渍法制备的Ｎｉ／ＭｇＯ催化剂不     

天然气二氧化碳转化制合成气的研究──催化剂抗积炭性能(英文)

采用脉冲色谱技术、ＸＲＤ、ＴＰＲ和ＸＰＳ等方法研究了在天然气二氧化碳转化制合成气反应中催化剂的抗积炭性能。实验结果表明,在Ｎ　Ａｌ２Ｏ３催化剂中添加ＣｅＯ２和ＭｇＯ助剂（催化剂记为Ｎｉ／ＡＲＭ）能有效抑制甲烷脱氢反应,提高二氧化碳消炭能力,增加催化剂的抗积炭性能。其主要原因是,添加ＣｅＯ２和ＭｇＯ助剂增加了活性组分镍的分散度,加强了活性组分和载体的相互作用。改性后的Ｎｉ／ＡＲＭ催化剂在１０２３Ｋ、二氧化碳／天然气／氧气比为２．４／０．１以及１１２３Ｋ、二氧化碳／天然气／氧气比为１．４／１／０．０５的条件下反应８００小时后活性不降低,产物中合成气（ＣＯ＋Ｈ２）摩尔百分含量始终保持在９４－９６％左右。说明该催化剂具有较高的活性、选择性和抗积炭性。     

La2O3—Ni／SrAl12O19催化剂上甲烷与二氧化碳重整反应的研究

采用ＸＲＤ，ＵＶ－ＤＲＳ，Ｈ２－Ｏ２滴定，ＴＰＲ，吡啶吸附红外光谱等技术，研究了Ｌａ２Ｏ３助剂对Ｌａ２Ｏ３－Ｎｉ／ＳｒＡｌ１２Ｏ１９催化剂的还原性，表面酸性，金属镍的分散度和抗烧结能力，以及对催化甲烷与二氧化碳重整制取合成气反应性能的影响。结果表明，在负载型的镍催化剂中，添加Ｌａ２Ｏ３助剂，能够削弱金属组分与载体之间的相互作用，降低催化剂的还原性，提高金属镍在催化剂表面的分散度和在反应过程中的抗烧     

添加碱金属对甲烷与空气制合成气催化剂性能的影响(英文)

考察了添加在镍基催化剂中的碱金属助剂对甲烷与空气制合成气的催化反应性能的影响。并用ＴＰＯ、ＴＰＲ、ＣＯ_２程序升温脱附（ＴＰＤ）、ＸＰＳ及ＣＯ脉冲色谱对催化剂进行了表征。实验结果表明,碱金属助剂对降低催化剂结炭有一定作用;催化剂抗积炭顺序为; Ｎｉ－Ｋ２Ｏ／ＣａＯ／Ａｌ２Ｏ３＞Ｎｉ－Ｌｉ２Ｏ／ＣａＯ－Ａｌ２Ｏ３＞Ｎｉ－Ｎａ２Ｏ／ＣａＯ－Ａｌ２Ｏ３＞Ｎｉ／ＣａＯ／Ａｌ２Ｏ３。在实验中,我们发现碱金属的添加使催化剂的Ｎｉ晶粒变大和吸附ＣＯ_２的能力增强,结合能发生不同程度的变化。这些实验结果从不同方面解释了碱金属助剂对催化剂活性和抗积炭性的影响。实验结果表明Ｎｉ－Ｌｉ２Ｏ／ＣａＯ－Ａｌ２Ｏ３具有较好的活性和抗积炭性。     

K-La-Ni/Si-2催化低碳烷烃与二氧化碳重整制合成气(英文)

Ｎｉ／Ｓｉ２催化剂具有较好的低碳烷烃与二氧化碳重整制合成气的反应性能，添加Ｌａ２Ｏ３助剂和Ｋ２Ｏ助剂可提高催化剂活性和合成气收率，从而进一步改善催化剂的低碳烷烃与ＣＯ２重整制合成气的反应性能，研制的ＫＬａＮｉ／Ｓｉ２催化剂，用于天然气与ＣＯ２重整反应制合成气可达９７％的低碳烷烃转化率和９５％以上的合成气收率。     

STUDIES ON REFORMING NATURAL GAS WITH CARBON DIOXIDE TO PREPARE SYNTHESIS GAS

采用固定床流动反应器和ＸＲＤ、ＴＰＲ等技术对添加了Ｌａ２Ｏ３助剂的Ｎｉ／αＡｌ２Ｏ３催化剂进行了研究。结果表明，经Ｌａ２Ｏ３改性后，催化剂的活性和稳定性得到提高，Ｌａ２Ｏ３的最佳含量为２％（ｗｔ）。脉冲试验结果表明，添加２％（ｗｔ）的Ｌａ２Ｏ３助剂，能够有效抑制甲烷脱氢性能，增加二氧化碳消碳活性。ＴＰＲ结果表明，添加Ｌａ２Ｏ３助剂，能够改变活性组分和载体之间的相互作用，增加镍的分散度，降低氧化镍的还原温度，提高重整反应的活性。     

甲烷、二氧化碳重整制合成气催化剂的研究──ⅠNi－Al_2O_3间的相互作用对

用固定床流动反应装置及ＴＰＲ、ＴＰＤ、ＸＲＤ、ＸＰＳ、ＴＥＭ等技术考察了因热处理温度不同而具有不同Ｎｉ－γ－Ａｌ_２Ｏ_３间相互作用的Ｎｉ／γ－Ａｌ_２Ｏ_３催化剂的甲烷、二氧化碳重整活性、还原性能、吸附性能、表面化学形态和抗积炭性能等。结果表明，低温热处理的催化剂具有易于还原、低温活性较高和抗积炭性能差的特性，经高温热处理的催化剂，由于Ｎｉ－γ－Ａｌ_２Ｏ_３间强的相互作用而使催化剂表面几乎全部形成了难以还原的“ＮｉＡｌ_２Ｏ_３”表面尖晶石，这虽然在一定程度上降低了催化剂的低温活性，但却使其抗积炭性能大为改观，尤其在反应温度大于７５０℃时，还可表现出与低温热处理催化剂趋于等同的高活性，实验中还观察到催化剂表面的积炭主要以空心炭丝的形式存在。     

Ni,Pd／Al2O3对丙酮加氢一步合成甲基异丁基酮性能比较

研究了Ａｌ２Ｏ３负载Ｎｉ、Ｐｄ催化剂上丙酮加氢一步合成甲基异丁基酮的反应活性。考察了不同Ｎｉ含量和不同Ｐｄ含量对活性的影响。结果表明，在载体Ａｌ２Ｏ３中加入不同含量的ＳｉＯ２后，会改善载体的性能，Ｎｉ／Ａｌ２Ｏ３催化剂中添加稀土元素Ｌａ或Ｃｅ后可改善催化剂的稳定性。     

氧化镍/莫来石-刚玉催化剂中添加La2O3的作用

用ＸＲＤ，ＴＰＲ，ＴＧ－ＤＴＡ考察了氧化镍／莫来石－刚玉催化剂添加Ｌａ２Ｏ３对ＮｉＯ性质的影响及两者间的相互作用，Ｌａ２Ｏ３使得催化剂中ＮｉＯ的晶格常数及分散容量增大，而晶相含量减少，还发现，添加Ｌａ２Ｏ３，使一次ＴＰＲ过程中ＮｉＯ还原温度升高，耗氢量增加了Ｌａ２Ｏ３对二次ＴＰＲ中ＮｉＯ还原温度的影响减小，耗氢量不受影响，Ｌａ２Ｏ３的添加方式及含量不同，对ＮｉＯ性质的影响也不相同。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.