液相低温合成甲醇初探

探讨了以 Raney- Ni/醇盐体系催化剂低温合成甲醇的可能性 ,得到了以三乙二醇二甲醚作溶剂时反应各影响因素的最佳条件 ;反应压力 ,5 MPa;反应温度 ,1 60°C;反应时间 ,5 h;H2 / CO=2 ;Raney- Ni用量 ,lg;Raney- Ni:CH3 ONa:CH3 OH=1∶ 2∶ 6(质量比 )。发现四氢呋喃是处理Raney- Ni时较好的除水剂     

丙三醇钛直接热分解制备纳米二氧化钛

针对以易水解的一元醇钛盐为前驱物,采用溶胶-凝胶水解法制备纳米二氧化钛时浪费大量溶剂、抑制剂和造成环境污染的问题,制备出一种新型的丙三醇钛盐,并通过直接焙烧丙三醇钛的方法制备了纳米级二氧化钛粉体.运用IR、XRD、DSC、SEM和TEM等手段对制得的丙三醇钛和纳米二氧化钛粉体进行了表征.结果表明,由丙三醇钛直接热分解可制备出具有完整、呈片状结构晶形的纳米二氧化钛,该方法简单可行,污染小、成本低,制得的粉体粒径主要分布在15~50nm范围内.     

双金属醇盐工艺处理复杂含金银物料的研究

甘油、木糖醇等低Ｃ多元醇，在有碱参与的条件下能与三氧化二锑很好地发生反应，生成甘油亚锑酸钠、木糖醇亚锑酸钠，溶液在一定的碱浓度下可保持稳定。氧化铜、氧化铋、氧化铅也能反应生成双金属醇盐，而氧化态的银被还原生成金属银。这样，用低Ｃ多元醇的强碱水溶液处理复杂的含金、银物料时，贱金属氧化物生成双金属醇盐溶解脱除的同时，金银等贵金属被富集在渣中。可用电沉积或中和水解的方法从醇盐溶液中回收各种有价金属，并实     

Low-temperature methanol synthesis in catalytic systems composed of nickel compounds and alkali alkoxides in liquid phases

Catalysts prepared from NaH, tert-amyl alcohol and nickel acetate were tested for CO hydrogenation in organic solvents in the range of 353–433 K and 1.0–5.0 MPa. Methanol was produced selectively under the studied conditions. Higher temperatures and higher pressures enhanced methanol productivity; a maximum space–time yield of 0.95 kg MeOH l⁻¹ h⁻¹, higher than that of the conventional methanol production process, was obtained at 433 K and 5.0 MPa. The addition of methanol to the catalyst did not significantly affect the product yields, but such addition did eliminate the induction period that was observed during the run in the absence of methanol addition to the catalyst. This suggested that methanol promoted the formation of a catalytically active species and/or that a certain amount of methanol was required to run a catalytic reaction cycle smoothly, in which methanol would be a reactant. The catalysts exhibited a catalytic decline over a short period due to the consumption of the alkoxide component.     

Changes induced in silk‐like polyester properties by alkoxides treatment

The action of alkali treatment in both aqueous and alcoholic media is investigated to attain silk‐like polyester fabric. The use of alkoxide solutions is more effective on polyester fabric. Rapid loss in weight up to 15–20% occurs at ambient conditions. Immersion and padding techniques are applied. The effect of treatment on some properties of polyester fabric are given through measurements of tensile strength, drapability, permeability, density gradient, crystallinity, thermogravimetric analysis, and scanning electron microscopy. Optimization of the treatment conditions is also suggested. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1829–1837, 2005     

纳米钛酸铅前驱体铅、钛复合醇盐配合物的合成与水解工艺

在（Bu4N）Br浓度为0．03mol／L的乙醇溶液中,电解钛片4h,然后电解铅片2h,每隔30min加入0．1mL乙酰丙酮,制得铅、钛金属醇盐,然后采用红外、拉曼光谱等测试技术对其进行了表征,纳米PbTiO3前驱体结构为PbTi（OCH2CH3）（6-y）-（acac）y（acac为乙酰丙酮基）。研究了水解温度、水解酸度、产物浓度、凝胶时间对前驱体水解的影响,当电解液在pH8．5、温度40℃直接水解时,产率达90％以上。真空干燥24h后得到纳米PbTiO3干凝胶,经X-射线衍射、电子透射显微镜测试,粉体粒径为10nm。     

烷氧基铝水解制备氢氧化铝过程正交实验研究

采用正交实验方法,考察了正戊氧基铝水解制备氢氧化铝过程中水解温度、水解时间、水与烷氧基铝摩尔比、老化温度和老化时间对氢氧化铝的晶粒尺寸、比表面积和孔体积的影响,并对影响机理进行了探讨。结果表明：老化温度是影响氢氧化铝晶粒尺寸和比表面积的最主要因素;水解温度是影响氢氧化铝孔体积的最主要因素,同时对比表面积和晶粒尺寸也有显著影响。其根本原因在于老化过程会促进氢氧化铝晶粒的生长,而水解温度决定烷氧基铝水解生成氢氧化铝的晶相组成。     

Effect of lithium butoxide additives on the anionic propagation of polystyryllithium in ethereal solvents

The addition of tertiary butoxide lithium (t-BuOLi) was found to slow down the anionic propagation of polystyryllithium (PStLi) in tetrahydropyran (THP), whereas, the addition of normal butoxide lithium (n-BuOLi) increases the rate over the investigated ranges of PStLi concentrations. Both lithium butoxides, which are tetrameric in ethereal solvents, also increase the conductance of PStLi in THP solution much more than expected on the basis of the separate conductances of PStLi and the lithium alkoxides and the increase is more important in the case of the addition of n-BuOLi than in that of t-BuOLi.These phenomena are fully accounted for by a similar mechanism as that invoked to explain the influence of the addition of lithium chloride (LiCl), which contrasts at first sight with the lithium alkoxides by displaying both a retarding and an accelerating effect at the lower and the higher concentrations respectively of the investigated PStLi concentration domain.This common cause of the observed phenomena consists of the dissociation of the dimers of LiCl or the tetramers of the lithium alkoxides into the free Li⁺-ion and the multiple anions (ClLiCl⁻ in the case of LiCl and (BuOLi)₃BuO⁻ in the case of the lithium alkoxides) but also of the often overlooked Li⁺-ion scavenging reaction by the LiCl dimers or the lithium alkoxide tetramers producing multiple cations. The first reaction providing Li⁺-ions represses the ionic dissociation of PStLi by a common ion effect reducing thereby the amount of free PSt⁻-anions which are the main contributors to the rate of propagation and resulting therefore, in retardation. The second one scavenging Li⁺-ions reduces the concentrations of free Li⁺-ions and increases therefore, the concentration of reactive free polystyryl anions and as a consequence accelerates the propagation reaction.The concentration of PStLi at which a crossover occurs from retardation to acceleration lies for the addition of LiCl in the investigated range of PStLi concentrations. For the addition of t-BuOLi calculations show that this crossover concentrations lies above the highest investigated PStLi concentration, whereas, for the addition of n-BuOLi it lies below the lowest investigated PStLi concentration giving the impression that t-BuOLi only retards the propagation and that n-BuOLi only accelerates but in actual fact the same mechanism is operating in all three cases.     

Preparation of PbZrO3–PbTiO3 Ferroelectric Thin Films by the Sol–Gel Process

Ferroelectric films, PbZr _x Ti_{1− x} O₃ ( x = 0 to 0.6), have been prepared from corresponding metal alkoxides partially stabilized with acetylacetone through the sol-gel process. The films dip-coated in an ambient atmosphere were heat-treated at 400°C for decomposition of residual organics and then at temperatures between 500° and 700°C for crystallization of the films. The perovskite phase precipitated at temperatures above 560°C, accompanied by an increase in dielectric constant. The dielectric constant of the films, which was comparable with that of sintered bodies, showed a maximum (∼620) at around x = 0.52 in PbZr _x Ti_{1− x} O₃. These films showed D – E hysteresis, with slightly higher values of coercive field, compared with those of sintered bodies.     

（Pb,La）TiO3材料合成的溶胶—凝胶方法

以金属醇盐和无机盐为原材料,用溶胶-凝胶法合成了(Pb,La)TiO_3三元系固溶体,所需合成温度约为460℃,而钙钛矿结构氧化物固相反应形成温度约为600℃。工艺参数对材料性能有重要影响。用醋酸作催化剂,使溶胶-凝胶工艺易于操作,能得到清晰的溶胶和透明的凝胶。对La含量为10at.％和21at.％的两种材料PLT10和PLT21的研究表明,随La含量增加,能保证成胶质量所允许的pH值范围变窄,工艺操作难度增大。已制备出含La量在21at.％以下性能良好的PLT材料。