苯乙烯-NOx光照的二次有机气溶胶生成

在烟雾箱内研究了温度为(301±2) K时苯乙烯-NO_x-air光照体系生成的二次有机气溶胶(SOA). 分别探讨了高相对湿度(RH＝72%)对SOA的化学组分、数浓度、产率等的影响. 通过长光程傅立叶红外(FTIR)得到苯乙烯-NO_x光照体系的气相产物主要有甲醛、苯甲醛、甲酸和CO等. 采用聚四氟乙烯(PTFE)膜对SOA进行富集, 用FTIR对其化学组分进行分析, 推得SOA的主要物种有过氧苯甲酸硝酸酯、苯甲酸羟基苯基甲酯和苯甲酸. 高相对湿度时气相产物中甲酸量显著提高, 同时SOA红外谱图中新增加了苯甲酸, 而酯中的羰基吸收峰却比低相对湿度时降低了, 从而证实了H₂O与Criegee双自由基反应生成苯甲酸的路径, 同时也间接地说明了Criegee双自由基与苯甲醛反应生成苯甲酸羟基苯基甲酯的存在. 高相对湿度时SOA的数浓度比低相对湿度时降低了约36%～44%, 但根据在膜上的SOA质量得到高相对湿度时SOA产率比低相对湿度时提高了约40%, 说明高相对湿度增大了SOA的粒子尺度.     

改性Pechini方法合成富锂正极材料Li[Li(1/3－x/3)CoxMn(2/3－2x/3)]O2及性能研究

通过改性Pechini方法合成不同Co含量的富锂正极材料Li[Li_(1/3－x/3)Co_xMn_(2/3－x/3)]O₂ (x＝0.4, 0.5, 0.6). XRD研究结果表明, 不同Co含量的富锂正极材料均具有良好的层状结构, 结晶度高. 电化学测试结果表明材料的初始容量随Co含量的增加而增加, 在200～220 mAh/g之间. 其中x＝0.4材料的循环性能最佳, 在0.5 C (100 mA/g)时, 循环50次后的容量保持率为75%. 容量微分曲线研究结果表明在3.5 V以下出现了Mn^4＋/Mn^3＋的还原峰, 并随循环次数的增加峰面积加大. 循环过程的XRD研究表明, 随着充放电次数的增加, 富锂正极材料的层状结构逐渐向尖晶石相转变, 且有杂质相MO_x (M＝Co, Mn)生成, 导致容量衰减.     

H2,CO和H2/CO在ZrO2催化剂上吸附行为研究

用insituFTIR法研究了H₂、CO及CO/H₂在ZrO₂表面的吸附行为.结果表明,H₂在ZrO₂表面吸附存在两种形态的羟基(即ZrOH和ZrOHZr),吸附温度增加,羟基数量增加.CO在200℃易与ZrO₂表面羟基作用形成甲酸盐物种,吸附温度升高时,该物种逐渐分解生成CO和ZrOH.当CO和H₂共存时,表面甲酸盐的量明显增加,并随温度增加,逐渐加氢形成甲氧基,最后生成甲烷.甲氧基的加氢过程较慢,所需反应温度也较高,被认为是CO加氢合成醇的速控步骤.     

铈基与钴基Co3O4-CeO2氧载体上甲烷化学链转化特性: 产物选择性控制

采用水热法制备了Co₃O₄/CeO₂(x)[x为钴铈原子摩尔比n(Co):n(Ce)=6:49:1]和Ce_1-yCo_yO_2-δ(y=0.10.4)2个系列复合氧化物, 并表征了材料的物理化学性质, 考察了这些氧化物作为氧载体参与甲烷化学链转化(化学链燃烧和化学链部分氧化)的反应性能. 结果表明, 2类复合氧化物的甲烷反应活性均明显优于单一氧化物CeO₂或Co₃O₄, 但2类氧载体上的甲烷反应产物的选择性具有明显差异. Ce_1-yCo_yO_2-δ氧载体形成了Ce-Co-O固溶体, 储氧能力明显增强, 体相晶格氧迁移速率与甲烷活化速率匹配较好, 甲烷反应产物以CO和H₂的合成气为主, 有利于甲烷的化学链部分氧化. Co₃O₄/CeO₂(x)氧载体中CeO₂与Co₃O₄之间的相互作用改善了材料的储氧能力和氧化活性, 其与甲烷反应时主要生成CO₂, 有利于甲烷化学链燃烧. 连续性化学链循环实验表明, 2类氧载体均具有较好的再生性能和循环稳定性.     

Pt/Al2O3催化剂用于丙烯选择性还原NO

分别采用浸渍法(IM)和溶胶-凝胶法(SG)制备了一系列不同铂负载量的催化剂,在固定床反应器上用C3H6作还原剂,测试了选择性还原NO_x的活性,结果发现,在IM法和SG法制备的催化剂中,活性组分铂最佳负载质量分数分别为0.5%和2%.针对两种催化剂,分别考察了氧浓度、丙烯浓度及反应气流量对选择性催化还原NO_x性能的影响,催化活性随丙烯浓度的增大而上升.2%Pt/Al₂O₃(SG)催化剂的抗SO₂性能好于0.5%Pt/Al₂O₃(IM)催化剂,H₂O的存在可明显拓宽活性温度范围,并向高温区间移动,在200～400℃范围内可有效净化NO_x.     

25 ℃时Ca5(AsxP1－xO4)3F固溶体的溶解度与稳定性研究

通过在25 ℃和不同pH值条件下对人工合成Ca₅(As_xP_{1－xO4)3F固溶体的溶解实验, 确定其稳定存在的pH值范围, 得出它的溶度积和生成的自由能(ΔGf⁰), 并讨论其用于沉淀法处理含砷废水的可行性. 结果表明, Ca5(AsxP1－xO4)3F固溶体在水中的溶解度和稳定范围与pH有关. 在酸性条件下, 水溶液中的As的浓度要比同种样品在中性和碱性条件下的浓度高10倍以上. Ca5(AsxP1－xO4)3F固溶体溶解时, As的浓度随着P∶As物质的量比升高而降低. 计算结果表明, 在25 ℃和pH＝6的条件下, Ca5(AsxP1－xO4)3F固溶体的溶度积和自由能随着P∶As摩尔比的升高而降低.}     

煤化学链燃烧Fe2O3载氧体的反应性研究

利用流化床反应器并以水蒸气作为气化-流化介质,研究了温度、反应时间、循环数对Fe₂O₃载氧体反应性的影响。实验表明,载氧体与煤气化产物的反应性随温度升高而增强,且温度越高,反应受化学反应控制时间越短。当温度高于900℃时,煤中碳转化为CO₂的比率大于90%,载氧体体现了很好的反应性,但反应温度低于850℃时,比率小于75%。反应温度900℃时,CO₂干基浓度随循环数而逐渐降低,CO、CH₄浓度增加,且CH₄浓度值大于CO。利用XRD、SEM分析了固体反应产物成分与微观形态结构。分析表明,Fe₂O₃的还原产物为Fe₃O₄,载氧体颗粒随循环数增加而逐渐烧结。     

基于位形熵模型的山梨醇玻璃焓松弛的量热分析

利用DSC技术考察了无定形山梨醇体系的焓松弛行为, 在10 K•min^－1的升温速率下测定了经历不同降温速率(0.5～20 K•min^－1)的山梨醇在玻璃化转变(T_g)前后的比热容[c_p(T)]. 利用基于位形熵演变的焓松弛现象学模型(GR模型)模拟了实验数据. 不论是否假设松弛过程存在一个亚稳极限态, 模型参数均能很好地重现经历不同热历史体系的升温c_p(T)曲线. 在物理意义明确的模型参数组中, 除了非指数参数随降温速率的增加而增加外, 其余均不随热历史的变化而变化. 拟合较低降温速率下c_p(T)曲线获得的GR模型参数的预测力明显好于在较大降温速率下获得的结果. 由于松弛时间对拟合过程中选择的“固定参数”的取值很敏感, 因此模型能否预测体系的比热容不能看成确定松弛时间的唯一依据. 在利用GR模型分析无定形山梨醇体系的脆度时, 如果选择极限假想温度作为T_g, 会导致计算结果明显小于文献值.     

胶质液体泡沫(CLA)的形成及其稳定性研究

以研究胶质液体泡沫(CLA)内部结构及其特性为最终目的, 对组成为十二烷基醇聚氧乙烯(3)醚(AEO-3)/正癸烷/十二烷基硫酸钠(SDS)/水的CLA体系形成过程和稳定动力学行为进行了电导率测定和光学显微观察. 通过上述两过程的电导率变化探明了CLA的形成和稳定性动力学行为, 并被光学显微照片所证实. 实验结果表明CLA的形成是一个低能量乳化过程, 经历了水相泡沫化→油相替代气泡乳化→CLA形成. 在整个乳化过程中, 没有发生相的转变现象, CLA呈O/W型乳状液. 其稳定性并不遵守一级动力学模型. 在常温下, 其电导率曲线呈直线关系; 当温度超过318.15 K时, 其电导率曲线近似于Langmuir等温线形. 并可用Sigmoidal模型σ_t=(σ₁－σ₂)/[1＋e^(t－t₀)/S] ＋σ₂较好的拟合, 式中, σ_t表示t 时的电导率值(μS/cm); t表示时间(min); σ₁, σ₂分别代表存储过程中电导率最小值和最大值(μS/cm); t₀对应于σ_t等于 1/2(σ₁＋σ₂)的时间t值(min); S描述了电导率曲线陡峭程度(min). 并提出了CLA的破乳过程包括液膜排液和液膜破裂两个阶段, 同时伴随有絮凝过程发生的稳定性机理.     

K2CO3修饰的铁锆复合氧载体-煤焦化学链气化制氢反应特性研究

以K₂CO₃修饰的Fe₂O₃和ZrO₂复合型氧化物为氧载体(K3-Fe70Zr30),在固定床装置上考察了温度和原料配比对煤焦化学链制氢过程中产气率及组成的影响。程序升温实验结果表明,煤焦与氧载体500 ℃时开始反应,温度高于750 ℃时反应速率快速增大;而还原态氧载体与水蒸气400 ℃时开始反应,当温度高于500 ℃时出口氢气浓度明显增大。恒温实验表明,随温度升高,产品气中CO/CO₂体积比增大,导致产氢量降低。随煤焦与氧载体比例增加,产品气体中CO/CO₂体积比增加,而产氢量先增大后降低,其最大值可达1.734 L/g。K3-Fe70Zr30氧载体在前两次循环能维持良好的反应活性,但在第3次循环反应中活性降低,而重新添加K₂CO₃之后氧载体活性恢复,表明氧载体活性降低主要是由于K₂CO₃的流失所致。     

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.     

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。     

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.

     

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.     

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.     

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^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

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。