预处理气氛对Co-ZrO2共沉淀催化剂结构的影响

考察了共沉淀Co-ZrO2催化剂在不同气氛(Ar、H2、CO和CO+H2)、不同温度下处理后, 催化剂织构、晶相以及形貌的变化规律. 结果表明, 在惰性气氛或氢气氛处理过程中, 催化剂在500 ℃以上发生明显烧结. 经上述处理并暴露于空气后, 催化剂中钴物种均以Co3O4形式存在, 且催化剂粒子外形无明显变化. CO气氛还原使催化剂破碎严重, 同时发生明显的积碳现象, 催化剂中钴物种以面心单质钴为主要形式. 合成气处理对催化剂破坏行为不明显, 但催化剂烧结现象严重, 催化剂中Co物种以面心立方和六方两种晶型共存.     

Effect of reduction temperature on the properties and Fischer-Tropsch synthesis performance of Fe-Mo catalysts

研究了还原温度对Fe-Mo催化剂性质及费托(F-T)合成性能的影响.采用N2物理吸附、X射线衍射、穆斯堡尔谱和H2程序升温脱附技术对催化剂进行了表征.结果表明,随还原温度升高,金属铁晶粒粒径增大,金属铁上的H2吸附量先升后降;催化剂还原度提高,反应态催化剂碳化铁含量递增.催化剂F-T合成性能在280℃、1.5MPa、2000h-1、合成气H2/CO比为2.0条件下在固定床反应器中测试.反应结果表明,随还原温度提高,催化剂接近稳态时的活性和重质烃选择性(C5+)先升后降,而甲烷选择性则先降后升.350℃还原催化剂具有最佳F-T合成反应性能.     

还原气氛对CoFe/SBA-15催化剂F-T反应性能的影响

考察了不同还原气氛处理CoFe/SBA-15催化剂对F-T反应性能的影响。结果表明,H2气氛下有利于六方钴的生成;催化剂的活性取决于钴含量,随着钴含量的增加,F-T反应中CO转化率增加,C5+选择性增加。随着铁含量的增加,催化剂表现了较高的CO2选择性。CO还原有利于立方钴的生成,导致催化活性相比H2还原的催化剂活性要低。同时CO还原容易产生积炭使催化剂的钴活性位被覆盖,导致甲烷选择性随着钴含量增加而升高。但碳化铁的生成有利于提高20Fe/SBA-15催化剂的活性,有利于低碳烃生成及C2~4烃烯烷比增加。     

还原温度对Co-La-Zr／AC催化剂合成气制高碳混合醇性能的影响

采用共浸渍法制备了Co-La-Zr/AC催化剂并考察了不同温度还原的催化剂的CO加氢催化性能. 结果表明,在3.0 MPa, 495 K, H2/CO(V/V)=2和GHSV=500 h-1 条件下,经703 K还原的催化剂, CO的转化率和醇的选择性分别为59.1%和42.0%, 其中C6～C18 的高碳醇在总醇中占到50.4%. XRD结果显示,反应后催化剂的主要物相为金属态的钴和碳化钴(Co2C). 还原温度可影响催化剂中钴的晶粒分散度和碳化钴的生成. 碳化钴的形成可能在合成气生成醇类的反应中起重要作用.     

还原-氧化预处理对双孔道钴基催化剂催化性能的影响

以双介孔分布MCM-41分子筛为载体,采用等体积浸渍法制备了钴基催化剂,并考察了还原-氧化预处理方式对催化剂结构及费托合成催化性能的影响。新鲜催化剂经预处理之后,XRD结果显示钴物种主要以单质钴形式存在,且主要以面心立方钴晶型出现,晶粒粒径由原来的8.4nm增加到22.6nm,由于晶粒粒径的增大,拉曼峰呈现蓝移特征。SEM及TEM表征表明,预处理后催化剂中钴物种在载体中有较好的分散性。H₂-TPR结果表明,新鲜催化剂经还原-氧化预处理后钴物种的还原温度降低,钴物种-载体间作用力增强。费托合成反应结果显示,经预处理后催化剂较新鲜催化剂活性低,甲烷选择性提高,但C_5~18的选择性明显提高,尤其是C_5~11的选择性可达到新鲜催化剂的两倍。     

FeMn、FeMnNa和FeMnK催化剂上合成气制低碳烯烃的比较(英文)

研究了钠、钾助剂对FeMn合成低碳烯烃催化剂结构及性能的影响.低温N2吸附、X射线光电子能谱(XPS)、X射线衍射(XRD)、H2程序升温还原(H2-TPR)、CO/CO2程序升温脱附(CO/CO2-TPD)、M?ssbauer谱和CO+H2反应的研究结果表明,增加Mn助剂含量促进了活性相的分散和低碳烯烃的生成,而过多锰助剂在催化剂表面的富集则降低了费托合成反应的CO转化率;钾助剂和钠助剂的加入均抑制了催化剂的还原并且促进了CO2和CO的吸附.比较还原后(H2/CO摩尔比为20)和反应后(H2/CO摩尔比为3.5)催化剂的体相结构可以发现,在FeMn、FeMnNa和FeMnK催化剂中,由于钾助剂的碱性和CO吸附能力较强,因此体相中FeCx的含量相对较高;而活性测试结果表明,FeMnNa催化剂拥有最好的CO转化率(96.2%)和低碳烯烃选择性(30.5%,摩尔分数).     

浸渍钠对铁基催化剂F-T合成浆态床反应性能的影响

以FeCuK/Si O2为母体催化剂,通过乙酸钠浸渍得到一组不同Na含量的费托合成铁基催化剂.采用原子发射光谱、低温N2吸附、程序升温还原和M ssbauer谱等技术对催化剂进行了表征.在H2/CO摩尔比为0.67,空速为2 000 h-1,压力为1.5 MPa和温度为250℃的条件下进行了浆态床F-T合成反应性能评价实验.结果表明,浸渍少量Na能提高催化剂的比表面积,促进铁物相的分散,而浸渍大量Na却大大降低了催化剂的比表面积,使催化剂中的铁物相聚集形成较大的颗粒;浸渍Na抑制了催化剂在H2中的第一步还原,但促进了催化剂在CO中的碳化;在原位合成气还原过程中,浸渍Na有利于催化剂的碳化.在500 h的运行实验中,浸渍Na的催化剂均表现出不同程度的失活现象.反应结果表明,浸渍Na对水煤气变换反应活性影响不大,对费托合成反应活性和烃产物选择性有较大的影响.在铁基催化剂上浸渍Na有利于C12 重质烃和低碳烯烃的生成.     

助剂对Co/Al2O3催化剂浆态床费托合成反应性能影响

考察了ZrO₂、Ru或Pt助剂对Co/Al₂O₃催化剂结构及浆态床费托合成反应性能的影响。实验结果表明,添加ZrO₂助剂可阻止或降低难还原铝酸钴的形成、促进催化剂的还原、提高Co/Al₂O₃催化剂对费托合成反应的催化活性、降低甲烷选择性并提高C₅₊烃选择性。H₂-TPR表征结果表明,少量Ru或Pt助剂均能降低Co-ZrO₂/Al₂O₃催化剂中钴物种还原温度(Co₃O₄→CoO和CoO→Co⁰),提高催化剂的还原度,催化剂呈现出良好的CO加氢反应活性。此外,催化剂组分间浸渍次序对费托合成反应性能有重要影响,载体γ-Al₂O₃先浸渍Zr组分,可有效抑制难还原化合物形成;Co、Ru组分共浸渍加强了Co和Ru组分密切接触程度,更利于钴物种的还原;Co、Pt组分依次浸渍更利于活性组分的均匀分布,催化剂具有最佳的费托合成反应性能。     

低温高活性熔铁催化剂上的超临界相费托合成反应

在固定床反应器中超临界相条件下研究了熔铁催化剂上的费托合成反应,发现在超临界介质中反应物和产物更容易扩散,较好地抑制了催化剂表面非活性碳的沉积,从而提高了费托合成反应中的CO转化率和烯烃选择性,增加了链增长因子,降低了甲烷选择性.同时,考察了超临界介质、反应温度、压力、H2/CO比和空速等条件对费托合成反应的影响.结果表明,C5-8正构烷烃在催化剂活性温度下都是适宜的超临界介质.当温度和压力都在介质的临界点以上时,介质表现出较好的传质与传热性能,可改善费托合成反应性能.     

还原温度对Fe-Mo催化剂性质及F-T合成性能的影响

研究了还原温度对Fe-Mo催化剂性质及费托(F-T)合成性能的影响。采用N₂物理吸附、X射线衍射、穆斯堡尔谱和H₂程序升温脱附技术对催化剂进行了表征。结果表明,随还原温度升高,金属铁晶粒粒径增大,金属铁上的H₂吸附量先升后降;催化剂还原度提高,反应态催化剂碳化铁含量递增。催化剂F-T合成性能在280 ℃、1.5 MPa、2 000 h^-1、合成气H₂/CO比为2.0条件下在固定床反应器中测试。反应结果表明,随还原温度提高,催化剂接近稳态时的活性和重质烃选择性(C₅⁺)先升后降,而甲烷选择性则先降后升。350 ℃还原催化剂具有最佳F-T合成反应性能。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

解决能源问题的新途径——光解水制氢的研究

面对日益枯竭的能源危机,氢能是一种洁净、最有前景的替代能源。目前在各种制氢的方法中光催化分解水制氢的研究最多,光解水过程中催化剂最关键,本文对利用太阳能光解水的途径、提高光催化反应效率以及光催化剂的开发研究进行了综述。     

黄酮化合物的合成研究进展

黄酮化合物是一类具有多种生物活性的天然产物,其经典的合成方法主要为查耳酮路线和β-丙二酮路线.近年来出现了许多新技术、新方法.本文介绍了2'-羟基查尔酮的氧化关环法、黄烷酮氧化法、改进的Baker-Venkataraman法及其他合成黄酮化合物的方法.