稀土固体超强酸S2O82-/ZrO2-SiO2-Sm2O3的失活及再生研究

研究了稀土固体超强酸催化剂是S2O8^2-／ZrO2-SiO2-Sm2O3的失活原因与再生方法，采用热重差热分析法考察了催化剂失活原因。结果表明，催化剂失活的主要原因是：①催化剂表面硫含量损失；②催化剂表面活性位被反应液中的有机物覆盖；③催化剂表面积碳。催化剂采用7种不同再生方法进行比较。催化剂最佳再生方法是用无水乙醇洗涤2遍；110℃干燥12h。     

二氧化碳和丙烯直接合成甲基丙烯酸Ni2(OCH3)2/SiO2催化剂的研究

采用表面改性法制备了负载型Ni2(OCH3)2／SiO2双核金属甲氧基配合物催化剂，利用IR、DSC、TPD和微反技术对催化剂的表面结构、化学吸附性质和催化活性进行了研究。结果表明，负载型双核金属甲氧基配合物Ni2(OCH3)2／SiO2中Ni^2 与载体SiO2表面O^2-以双齿配位形式键合；二氧化碳在催化剂表面存在桥式吸附态和甲氧碳酸酯基物种两种吸附态，丙烯则只有一种吸附态；在适宜反应条件下，CO2和丙烯在Ni2(OCH3)2／SiO2催化剂上可以高选择性地合成甲基丙烯酸，反应物分子共吸附于催化剂表面同一活性单元以及羧酸根与丙烯解离吸附态的形成是反应顺利进行关键因素．     

SO4^2-/La2O3-ZrO2催化合成亚油酸乙酯

将SO4^2/ZrO2负载镧制备了新型催化剂SO4^2-/La2O3-ZrO2,以亚油酸和乙醇的酯化反应为探针，考察了不同制备条件对催化剂性能的影响，结果表明，La^2＋浸渍浓度为0．07mol／L，经110℃烘干后于500℃焙烧3h所得催化剂活性最好。采用正交实验法对影响酯化反应的因素进行考察，最佳实验条件为n（醇）：n（酸）：6：1，反应时间6h，催化剂用量3％（亚油酸），酯化率可达93．7％．且该催化剂具有良好的重复使用和再生能力。     

SO4^2-／TiO2-La2O3催化合成丁酮1，2-丙二醇缩酮

报道了以稀土改性固体超强酸SO4^2-／TiO2-La2O3为催化剂，通过丁酮和1，2-丙二醇反应合成了丁酮1，2-丙二醇缩酮，探讨了SO4^2-／TiO2-La2O3对缩酮反应的催化活性，较系统地研究了酮醇物质的量比，催化剂用量，反应时间诸因素对产品收率的影响。实验表明：SO4^2-／TiO2-La2O3是合成丁酮1，2-丙二醇缩酮的良好催化剂，在n醇：n酮=2．5：1，催化剂用量为反应物料总质量的0．50％，环己烷为带水剂，反应时间2．0h的优化条件下，丁酮1，2-丙二醇缩酮的收率可达68．7％。     

固体超强酸SO42-／ZrO2-TiO2催化合成富马酸二甲酯

研究了以SO4^2-/ZrO2-TiO2固体超强酸为催化剂，催化合成富马酸二甲酯（DMF）的反应。研究了催化剂的制备条件，原料配比、反应时间及催化剂用量等条件对DMF收率的影响。结果表明：该催化剂有较好的催化活性，DMF的收率达到91．6％。     

固体酸S2O2-8/ZrO2-SiO2催化合成马来酸二辛酯

用S2O8^2-浸渍锆硅复合氧化物，制得固体酸催化剂S2O8^2-／ZrO2-SiO2。用马来酸酐与正辛醇的酯化反应考察了催化剂的活性，并与硫酸、对甲苯磺酸等催化剂的催化效果比较。结果表明：对于给定反应，S2O8^2-对ZrO2-SiO2的促进作用明显高于S24^2-；当n(Zr)：n(Si)为l：6，用硝酸铵作硅酸钠的沉淀剂，用0．7mol/L，的过硫酸铵浸渍12h，在550℃下焙烧3h制得的催化剂S2O8^2-／ZrO2-SiO2具有最高的催化活性，用于催化马来酸酐和正辛醇的酯化反应，可得无色透明的酯化产物，3h内酯化率达98．4％，较S2O8^2-／ZrO2-SiO2催化剂的酯化率提高了约18％．     

CeO2-ZrO2对柴油机油烟氧化和钾催化剂热稳定性的影响

研究制备了硝酸钾负载于不同氧化物（CeO2、Ce0.5Zr0.5O2和ZrO2）上的催化剂用于柴油机油烟的燃烧。试验中，将制备好的催化剂在800℃老化处理24h，然后采用程序升温氧化工艺评价该催化剂的催化活性。     

2-辛醇气相脱水合成2-辛烯

研究了负载型脱水催化剂对2-辛醇气相脱水合成2-辛烯的催化作用，由固定床反应器考察其催化性能，最佳工艺条件:温度320 ℃左右，空速0.35 h^－1,2-辛醇转化率98％以上，2-辛烯产率96％。该催化剂稳定性好，与传统脱水催化剂相比,具有2-辛烯收率高、产品质量好和催化剂单耗低的优点。     

固体超强酸SO42-/TiO2-Al2O3-SnO2催化合成DBS

以固体超强酸SO4^2-／TiO2-Al2O3-SnO2为催化剂、葵二酸和正丁醇为原料合成了癸二酸二丁酯(DBS)。研究了反应时间、醇酸物质的量比、催化剂用量等对酯化率的影响。结果表明：最佳反应条件为以0.05mol葵二酸为基准，n(酸)：n(醇)=1：4，催化剂0．5g，反应时间3．5h，此时酯化率达97．5％，产品质量分数大于98％；催化剂重复使用6次后，催化活性基本不变。     

制备条件对B2O3/TiO2-ZrO2催化剂结构的影响

采用XRD和低温氮吸附等测试方法，研究了制备条件对TiO2-ZrO2催化剂的结构性质和催化性能的影响。结果表明，选择合适的焙烧温度，并用适量的B2O3改性后，能大大改善催化剂的孔结构参数；孔分布向更大的中孔方向移动，使反应物分子可到达的孔体积增大，提高了催化剂的内表面利用率，有利于环己酮肟气相Beckmann重排反应的进行。     

柯尔本类似律在化工传递过程中的应用

柯尔本类似律不仅形式最简单,而且能较好地与化工传递过程的实验数据相吻合.本文介绍了柯尔本类似律、研究了柯尔本类似律的适用范围.结果表明:柯尔本类似律适用于无形体阻力的工况；对于有形体阻力的工况,同一设备内的传热与传质的柯尔本j因数仍可近似相互换算.     

钙镁磷肥生产中微量元素的自动添加

在传统钙镁磷肥生产中,添加作物生长需要的微量元素,是以固体无机盐加入半成品中制得。现介绍微量元素以液态形式自动添加的原理、工艺流程、工艺条件和实施效果。微量元素实现自动添加,产品质量稳定,从而提高了企业的经济效益。     

Catalytic pre-wave of nickel(II) in presence of cocarboxylase (disulfide form) in borate medium

A brief study is made of the nickel(II) polarography in borate medium. The nickel(II) in borate medium gives one or two waves depending on its concentration as well as the medium composition.In a borate medium, cocarboxylase in its disulfide form gives a nickel(II) pre-wave. The effects of the cocarboxylase (disulfide form) concentration, nickel(II) concentration and mercury column height on the pre-wave are described.The effect of neutral salts on the pre-wave is studied and it is seen that an increase in the ionic strength is accompanied by a decrease in pre-wave current, being of decreasing effect in the order K⁺ < Na⁺ < Li⁺. The electrocapillary curves are present, and it is shown that the presence of cocarboxylase (disulfide form) in the solution causes a decrease in the interfacial tension.The results are discussed and a mechanism for the electrode process of the pre-wave is proposed. Using the approximate method for the catalytic currents, nickel(II) and cocarboxylase-thiol are shown to form the catalytic complex in the relationship 1:1.     

应用美兰吸附法测定纤维素表面积的讨论

以Prism4.0软件包将不同纤维材料吸附美兰的数据拟合Scatchard方程、Klotz-Hunston方程、Langmuir方程的一般形式和单点双曲线吸附方程,据此研究了由美兰等染料分子在纤维基质表面上的吸附从而推算基质的表面积的方法机理和局限性。分析表明Langmuir模型和单点双曲线模型的拟合得到的饱和吸附量为外推值,会导致测量结果失真;而用Sigmoidal dose-response(Variable slope)模型拟合时,则能给出真实吸附量。研究结果还显示,由纤维素分子链自由羟基所介导的美兰吸附不会发挥主导作用,而红外ATR结果和美兰的脱吸附试验表明美兰在纤维素表面上的吸附应为物理吸附,所以根据美兰分子平卧于纤维表面面积162 ?,计算纤维表面积,得到了四种纤维材料的比表面积。但由于真实界面浓度的确定方法仍存在矛盾,也缺少一个直观的检测标准,因此文章中给出的数值仍为一相对的比较值。     

Mesomorphic form of isotactic polypropylene in stereodefective polypropylene: Solid mesophase or liquid-crystal like structure

A study of the crystallization of the mesomorphic form of isotactic polypropylene (iPP) in samples of different stereoregularity prepared with metallocene catalysts is presented. Contrary to what claimed in the literature, we have found that the mesomorphic form can be obtained by quenching of the melt at 0 °C also in the case of low stereoregular samples, provided that the samples are kept at 0 °C for long time. The key is the formation of mesomorphic bundles with chains in ordered 3/1 helical conformation of size large enough to be stable and inhibit the crystallization of the α form at room temperature. For stereoirregular samples the concentration of long ordered helical stretches is low and this requires long residence time at 0 °C for the formation of mesomorphic aggregates of size larger than the critical size. This result provides evidence that the mesomorphic aggregates are not formed as a result of a cooperative process driven by entropy, as in the case of liquid crystals, but rather they form via a nucleation and growth mechanism, as in the normal crystallization processes, according to the idea that the mesophase of iPP is a highly defective crystalline form.     

Note on stability of p-nitrophenol in aqueous solutions

It has been shown that p-nitrophenol (PNP) solution is stable only at pH ≥ 9 when PNP is in the completely ionised form. In benzene, PNP exists in a neutral molecular form. These considerations are important in the estimation of surface areas of solids by adsorption of PNP from solution.     

The possible role of fissure formation in the prevention of coking pressure generation

Fissure patterns have been studied for both high-volatile, low-coking pressure coals and low-volatile, high-coking pressure coals. The high-volatile coals form an extensive pattern of interconnected fissures, which seem to form early on and extend further toward the plastic region than the low-volatile coals, which form only a few fissures that do not extend very far into the charge. It is proposed that the combination of high-fluidity and extensive fissure network present for high-volatile coals may assist in allowing continual release of volatiles throughout the coking process and play a part in preventing the generation of high gas pressures. It was also found that a higher proportion of the volatiles for the low-volatile, high-coking pressure coals is released after the coal has been converted to semi-coke, which may play a role in preventing the effective release of gas.     

高压换热器爆管的原因分析

对高压换热器爆管样品进行化学成分、力学性能、腐蚀产物和金相的检验,分析裂纹形成的原因。裂纹的产生是由应力腐蚀引起的。产生应力腐蚀有两个原因,一是换热管在制造过程中有磨损,表层形成形变马氏体。二是换热管弯管成形后弯管段消除应力热处理不彻底。     

Nucleation behavior of glutathione polymorphs in water

Nucleation behavior of glutathione (GSH) polymorphs in water was investigated by experimental method combined with classical nucleation theory. The solubility of α and β forms GSH in water at different temperatures, and the nucleation induction period at various supersaturations and temperatures were determined experimentally. The results show that, in a certain range of supersaturation, the nucleation of β form predominates at relatively higher temperature, while α form will be obtained at lower temperature. The nucleation kinetics parameters of α and β form were then calculated. To understand the crucial role of temperature on crystal forms, “hypothetic” nucleation parameters of β form at 283.15 K were deduced based on extrapolation method. The results show that the interfacial tension, critical free energy, critical nucleus radius and nucleus number of α form are smaller than that of β form in the same condition at 283.15 K, which implies that α form nucleates easier than β form at low temperature. This work may be useful for the control and optimization of GSH crystallization process in industry.     

Solution of the problem of the form and tension of a filament in its three-dimensional balloon during twisting

Systems of differential equations in cartesian and cylindrical coordinates are obtained to describe a flexible filament rotating in a resisting medium. The concept of the unit aerodynamic drag coefficient of the filament is introduced in addition to the assumptions used in previous studies. The systems of differential equations that were obtained are solved in analytical form using the assumptions that were made. A value is found for the new concept of unit aerodynamic drag coefficient, and ways are described to study it and determine its value for different filaments in practical applications. Complete mathematical expressions are obtained to calculate parameters that are of practical importance in the twisting of a filament - its tension, the maximum radius (diameter) of the torsion balloon, and the conditions under which multiple balloons are formed. It is established that the problem of the form and tension of a filament during its twisting cannot be solved in final form without allowance for the resistance of the medium.