铁助剂对Rh-Mn-Li/SiO2催化剂表面上的CO脱附和CO加氢行为的影响

 采用一氧化碳程序升温脱附（CO－TPD）和吸附的一氧化碳加氢程序升温表面反应（TPSR）考察了Fe助剂对Rh基催化剂上CO的脱附行为及吸附CO的加氢行为的影响．CO－TPD实验表明，在Rh／SiO2催化剂上CO有三个脱附峰．在Rh－Mn－Li／SiO2中加入0．05％Fe后，高温脱附CO比Rh／SiO2催化剂上相应的CO量大．增加Fe的负载量，CO的脱附量减少．TPSR实验中，CO加氢反应的主要产物是甲烷．不同组分的催化剂上甲烷的生成温度有如下顺序：Rh／SiO2（482K）＜Rh－Mn－Li／SiO2（489K）＜Rh－Fe／SiO2（494K）＜Rh－Mn－Li－Fe／SiO2（501K）．甲烷峰的产生伴随着CO（s）高温脱附峰的消失，说明甲烷是由强吸附的CO加氢生成的．     

CO和NO在Rh2-V/SiO2催化剂上共吸附的红外光谱

应用CO和NO吸附态原位红外光谱方法研究了还原态Rh2／SiO2，Rh2－V／SiO2催化剂上的活性中心铑的状态和助剂钒的作用. Rh2催化剂用Rh2（CO）4Cl2化合物制备. 在还原Rh2／SiO2催化剂上，CO吸附出现四个红外吸收峰：2085，2028cm－1（孪生态吸附RhⅠ（CO）2），2060cm－1（线式吸附RhⅡCO），1867cm－1（桥式吸附RhⅢ2CO）．在还原Rh2－V／SiO2催化剂上，CO在RhⅡ和RhⅢ中心上的吸附峰大大减弱，可以解释为Rh°向钒离子转移电子生成了带正电荷的铑中心（Rhδ＋）；同时RhⅠ（CO）2键能增加，降低了孪生CO被NO置换的程度。     

CO加氢合成C2含氧化合物Rh-Sm-V-Li/SiO2催化剂的研究

使用加压下的CO加氢反应和程序升温还原(TPR),吸附氢的程序升温脱附(H2-TPD),以及H2和CO吸附等技术,研究了Rh-Sm-V-Li/SiO2催化剂上Sm,V和Li促进剂对合成二碳含氧化合物的促进效应.结果表明,Sm和V加入到Rh/SiO2中使催化剂的活性和生成二碳含氧化合物的选择性显著提高,催化剂上的Sm3+不易被还原,Sm的加入起着提高Rh分散度的作用,使催化剂上H2和CO吸附量提高,并促进乙酸和乙醛的生成;催化剂上的高价钒离子容易还原成低价钒离子,并迁移覆盖金属Rh的表面,使催化剂上H2和CO吸附量降低.低价钒具有良好的贮氢能力,使催化剂的加氢能力显著提高,促进乙醇的生成.     

Pd对Zr－Mn－K催化CO加氢合成甲醇与异丁醇的影响

 考察了添加Pd对Zr－Mn－K催化CO加氢合成甲醇与异丁醇的影响．与Zr－Mn－K催化剂相比，Pd／Zr－Mn－K催化剂的催化活性及异丁醇选择性明显升高．在SV＝10000h－1，p＝8．0MPa和T＝673K的反应条件下，1．5％Pd／Zr－Mn－K催化剂上醇的时空收率由原来的122．8升高到232．6g／（kg·h），异丁醇的选择性由原来的15．5％升高到21．7％．当Pd的添加量大于1．5％时，催化剂的活性及异丁醇选择性开始下降．H2和CO吸附实验结果表明，Pd／Zr－Mn－K催化剂表面维持有较高的H2和CO吸附量，有利于甲醇与异丁醇生成速率的提高．当Pd的添加量超过1．5％时，Pd的分散度降低，粒径变大，吸附H2和CO的量减少，致使合成甲醇和异丁醇的性能降低．     

锂助剂对Rh-Mn/SiO2催化CO加氢制碳二含氧化合物性能的影响

 采用 CO 加氢反应、静态化学吸附、程序升温还原、CO 程序升温脱附和程序升温表面反应等技术研究了助剂 Li 对 Rh-Mn/SiO2 催化剂上 CO 加氢合成碳二含氧化合物性能的影响. 结果表明, Li 的加入及其负载量的增加抑制了烃类, 特别是 CH4 的生成, 而对碳二及碳二以上烃类的选择性影响较小. Li 的加入还提高了碳二含氧化合物的选择性, 主要是乙酸的选择性, 但同时降低了 Rh 基催化剂的 CO 加氢活性. 表征结果表明, Li 的加入既降低了催化剂解离 CO 的能力, 又减少了催化剂上 CO 解离活性位的数量, 从而降低了 Rh 基催化剂上 CO 加氢的速控步骤——CO 解离反应的速率. Li 负载量对 Rh-Mn/SiO2 催化剂上 H2 和 CO 的化学吸附量影响较小, 这表明并非所有的 Li 都和 Rh 发生了相互作用, 而是有相当一部分 Li 只是分散在载体 SiO2 上, 并没有与 Rh 发生接触.     

CO加氢合成C2含氧化合物Rh-Sm/SiO2催化剂的研究

使用加压下的CO加氢反应、程序升温还原(TPR)、吸附氢的程序升温脱附(H2-TPD)以及CO和H2吸附等技术,研究了Rh-Sm/SiO2催化剂上Sm促进剂对合成二碳含氧化合物的促进效应.结果表明,Sm加入到Rh/SiO2中使催化剂的活性和二碳含氧化合物的选择性显著提高,催化剂上的Sm3+不易被还原,Sm的加入起着提高Rh分散度的作用,使催化剂上CO和H2的吸附量增大,倾向于促进乙酸和乙醛的生成.     

Rh-Mn-Li/SiO2催化剂的吸附量热和红外研究

通过在最优Rh含量基础上对金属配比的再优化,成功地改进了Rh-Mn-Li/SiO2催化剂的CO加氢性能;并采用微量吸附量热和红外等表征手段,考察了助剂Mn和Li促进作用的本质.结果表明:助剂Mn和Li的添加,使孪式和线式吸附CO的碳氧键强度增加,并同时削弱了桥式吸附CO的碳氧键或者使其转化为更易于解离的倾斜式CO吸附物种,从而同时增加了Rh基催化剂的CO解离和插入能力,提高了其活性和C2含氧化合物选择性.另一方面,Mn和Li的添加显著地降低了Rh基催化剂表面H的数量和稳定性.催化剂加氢能力显著降低极大地抑制了CH4的生成,从而有利于C2含氧化合物选择性的进一步提高.     

Rh基催化剂上CO加氢制C2含氧化物的原位红外光谱研究

 用原位红外光谱考察了Rh-Mn-Li-Fe/SiO2和Rh/SiO2催化剂表面上CO的吸附态及CO加氢反应过程中吸附物种的变化. 结果表明,CO在Rh/SiO2催化剂上仅有线式吸附态存在,而CO在Rh-Mn-Li-Fe/SiO2催化剂上既有线式吸附态存在,又有孪生吸附态存在. 这说明Rh-Mn-Li-Fe/SiO2催化剂中Rh的分散度较高. 经CO加氢反应(3.0 MPa,593 K)后,在Rh-Mn-Li-Fe/SiO2催化剂上可观测到C2含氧化物前驱物种的吸收谱带,而在Rh/SiO2催化剂上未观测到相应的谱带; CO在这两种催化剂上主要以线式吸附态存在,孪生吸附态基本消失. 结合催化剂对CO加氢的催化性能,可以认为线式吸附的CO对生成C2含氧化物有贡献. Rh-Mn-Li-Fe/SiO2催化剂的高活性是由于助剂的存在削弱了其表面吸附CO的 C-O键,促进了CO的活化,从而有利于C2含氧化物前驱物的生成.     

K2O助剂对合成碳酸二甲酯用Cu/Ni/ZrO2-SiO2催化剂的吸附和催化性能的影响

 用等体积浸渍法制备了ZrO2－SiO2（ZrSiO）表面复合氧化物负载的Cu－Ni催化剂,并用IR,TPR,TPD及微反技术考察了K2O助剂对CO2和CH3OH在Cu－Ni／ZrSiO催化剂表面上的吸附及合成碳酸二甲酯（DMC）反应性能的影响．结果表明：加入K2O助剂使CO2在催化剂表面上的吸附增强,当n（K）／n（Cu＋Ni）＝15％时,CO2在催化剂表面上吸附后生成K2CO3;CH3OH在催化剂表面上的解离吸附态（CH3O－和H＋）的吸附减弱;CO2和CH3OH在Cu－Ni／ZrSiO催化剂表面上反应的主要产物为DMC,H2O,CO和CH2O;随着K2O助剂的加入,反应转化率及DMC选择性提高,副产物（CO和CH2O）的选择性下降．根据实验结果,探讨了K2O对催化剂表面活性中心电荷分布的影响．     

CO加氢Rh-Mn-Li/SiO2催化剂配比的优化及其CO脱附行为

通过优化Rh-Mn-Li/SiO2催化剂配比,大大地提高了其催化CO加氢合成C2含氧化合物的性能,并利用吸附CO的程序升温脱附(CO-TPD)和程序升温表面反应(TPSR)等方法考察了助剂Mn和Li对Rh基催化剂表面CO脱附行为的影响.结果表明,在543~573K内,Rh担载量为1.5%时催化剂的Rh效率(ERh)最高.少量Mn的添加显著地提高了Rh基催化剂的ERh,C2含氧化合物的时空收率(STYC2-oxy)和选择性(SC2-oxy).并且随着Mn含量增加,ERh和STYC2-oxy在Mn=0.53%时最高,但SC2-oxy一直缓慢增加.而随着Li含量增加,SC2-oxy显著增加,但是ERh和STYC2-oxy明显下降.CO-TPD和TPSR结果表明,助剂Mn和/或Li的添加改变了催化剂表面解离CO活性中心的数量及其解离CO的能力,从而影响催化剂的活性.另一方面,Mn和Li的添加提高了催化剂表面弱吸附CO的相对数量,从而使SC2-oxy提高.     

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。     

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.     

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.     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

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.     

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。     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。