碳还原氧化铜的热效应及实验现象

碳还原氧化铜是中学化学的重点内容之一。在中学化学教科书里编排了这一变化的演示实验。在同一节教材里,还初次提出了“吸热现象”、“放热现象”2个概念,这就使掌握碳还原氧化铜的热效应,成为教师在教学中的需要。     

一氧化碳还原氧化铜的微型实验

在师专无机化学实验和化学教学法实验中均有一氧化碳还原氧化铜的实验内容。一氧化碳有剧毒,所以,做一氧化碳还原氧化铜的实验时,应力求试剂用量小,减少污染,保证安全。     

氨气制备和性质的微型组合实验

利用微型气体实验仪设计了氨气的制备和性质的微型组合实验装置,依次探究了氨气的制备、收集、检验和氨气还原氧化铜、氨气的喷泉实验等,观察到了氨气还原氧化铜的实验现象。具有操作简便,现象明显,安全环保等特点。     

木炭还原氧化铜实验的新认识

正木炭还原氧化铜是义务教育阶段的疑难实验,大家过多地把目光集中在原料的用量比、装置的改进及加热方式的优化上,而忽视了一氧化碳对整个实验的影响~([1-2])。对此实验改进后发现了一个很好的一氧化碳还原氧化铜的实验。1实验过程(1)将1cm×5cm的铜片加热至红热状态,然后自然冷却,铜片表面被氧化成氧化铜。     

使用变温原位X射线衍射技术认识氧化铜在氢气和一氧化碳气氛下的物相变化*

实验与理论相结合是化学专业教与学的原则。通过运用原位X射线衍射技术(in-situ XRD)探究氧化铜在氢气和一氧化碳气氛下的还原,结果发现无论在氢气或一氧化碳气氛下,从300 ℃开始,氧化铜逐渐被还原为氧化亚铜和铜单质,且该3种物相同时存在。直至温度升至450~500 ℃时,所有的氧化铜和氧化亚铜全部变为了铜单质。实验结果表明氧化铜的还原并非是一个由CuO → Cu2O → Cu逐步还原的单一过程,理论上可以得到的纯氧化亚铜物相在实验过程中并未得到,对此结果进行了分析。另外,将大型仪器尤其是原位表征技术推广到本科教学中具有重要意义。     

氢气还原氧化铜实验的改进

对现行初中化学教材中关于氢气还原氧化铜的实验,按教材氢气还原性实验说明进行,都不易出现光亮的红色这一实验现象。分析其原因与氧化铜粉末跟试管接触不紧密以致氧化铜加热温度不够有关。     

白磷还原氧化铜实验的巧妙设计

在实证分析、理论证据的基础上,设计了白磷还原氧化铜的实验,得出白磷可以夺取部分金属氧化物（如氧化铜）中的氧,具有一定的还原性。     

对碳还原氧化铜的改进

在初中化学和高中化学进行用碳粉还原氧化铜实验时,都是按照书上的方法把碳粉与氧化铜混合后加热进行实验。这样由于氧化铜和碳粉混合在一起了,所以还原出来的铜就渗杂在碳粉中很难看见,即使仔细去找也只能看到星星点点的颗粒,效果不好。我在今年做这个实验时改变了一下方法,不把碳粉和氧化铜混合,先把碳粉均匀的放在试管的下端,然后再把氧化铜均匀的撒在碳粉上,按书上的装置装好,用喷灯加热3—5分钟就可以看到一层红棕色的纯铜浮     

氢气还原氧化铜及氯气跟金属钠反应

一氢气还原氧化铜在干燥试管底部用滴管滴入普通水一滴,转动试管,使试管底部涧湿,将适量黑色氧化铜倒入,与涧湿的试管底部充分接触,试管底部就附上了一薄层氧化锏,将多余氧化铜倾出,按课本要求做氢气还原氧化铜实验,可得到光亮的红色铜,若强火加热,还可得到铜镜。     

一氧化碳还原氧化铜与氢气还原氧化铜的实验操作为什么不同?

为防止氨气与空气混和受热发生爆炸,在用氢气还原氧化铜的实验操作中,要求先通氢气以排除试管里的空气,再加热氧化铜。还原完毕,先撒去酒精灯,还要继续通入氢气,至试管冷却,以防止还原成的金属铜,遇到空气再被氧化为氧化铜。用一氧化碳还原氧化铜的实验,要求先加热玻璃管里的氧化铜粉末,再通入一氧化碳气体,停止加热后,不再继续通入一氧化碳,这是因为:一氧化碳是极毒的气体,装置和无毒的氢气不同,操作也必然不相同;再者,一氧化碳虽也有易燃,易爆的性质,     

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。