无水三氯化铝催化乙醇脱水反应制乙烯的实验研究

针对浓硫酸或五氧化二磷作催化剂的不足,该研究采用无水三氯化铝催化乙醇制乙烯,可使反应体系在120~130℃左右产生大量乙烯气体。同时从理论上探究了无水三氯化铝催化乙醇脱水的机理,并从教学演示实验的角度改进了反应装置,取得了较好的实验效果。     

乙醇脱水制备乙烯综合性实验设计

从实验设计的思路、实验目的、实验设备、实验操作流程、实验思考题、实验数据记录和实验结果的处理等方面介绍乙醇脱水制备乙烯综合性实验的设计与实现过程.     

三氯化铁催化乙醇脱水制乙烯的实验研究

现行高中化学教材中乙醇脱水制乙烯的实验多用浓硫酸或五氧化二磷作催化剂,均存在诸多缺陷.笔者尝试用三氯化铁作催化剂,可使反应体系在80℃左右产生大量乙烯气体,且反应时间短,现象明显,几乎无副反应发生.     

对实验室制乙烯的研究

１实验中存在的问题实验室制乙烯常采用乙醇和浓硫酸于１７０℃时的脱水反应．该实验存在的主要问题是炭化比较严重,给实验造成一些不利影响,主要有以下几点：（１）由于大量乙醇被炭化使乙烯的产气量减少。（２）伴随乙醇炭化产生的大量ＳＯ２不仅污染教学环境,对乙烯的性质实验也有明显干扰。（３）伴随乙醇炭化还能发生一些更复杂的副反应,有资料称该实验还可能生成Ｈ。、ＣＨ４、ＣＯ等气体,致使点燃乙烯气体时火焰颜色明显发生变化,呈现出Ｈ２、ＣＯ等气体燃烧时特有的蓝色,这也影响对乙烯性质的认识。总之,炭化是影响该实验质…     

生物乙醇催化脱水制乙烯的研究进展

阐述了利用生物质能源的重要性,介绍了生物乙醇催化脱水制乙烯的发展现状,特别是其催化剂的研究状况。针对乙醇脱水制乙烯催化剂存在的问题,提出当前催化剂的发展趋势。     

乙醇脱水演示实验问题的教学探究

对苏教版中乙醇脱水制取乙烯的演示实验中存在的问题进行了研究,改进了实验条件,提出了更合理的实验方案:采用磨口有机玻璃仪器,调整反应物之间的投料比,使用气压差方式等进行有害气体的吸收,体现绿色化学的实验理念,使课堂教学焕发出新的生机和活力。     

高中化学实验的项目式教学*——乙醇消去反应制备乙烯的实验探究

以乙醇消去反应制备乙烯改进实验探究为项目,通过“分析浓硫酸催化乙醇消去反应制备乙烯实验不足的改进方向”“设计并实践乙醇消去反应制备乙烯的实验改进方案”“汇报实验并提出最终改进方案”3个任务,深化对核心知识消去反应的理解和对实验方案设计方法及实验探究过程的深刻体会,并在问题解决中发展“科学探究与创新意识”素养。     

ZSM-5分子筛催化乙醇脱水制乙烯反应机理

正乙烯是有机化工和石油化工最重要的基础原料。目前,乙烯主要来源于石油裂解。生物质乙醇制乙烯以及高级烃类化合物受到了学术界和工业界的关注~(1–3)。与传统的乙醇脱水制乙烯的氧化铝催化剂相比,沸石分子筛,尤其是ZSM-5或改性ZSM-5,具有更高的乙烯选择性和低温反应活性~(4,5)。乙醇脱水的第一步就是乙烯的生成,随后乙烯的     

关于五氧化二磷在乙烯制备中应用的讨论

实验室乙烯的制备常采用乙醇和浓硫酸共热的方法,由于浓硫酸具有强脱水性和强氧化性,反应中会产生大量的积碳及CO2和SO2气体,严重影响着乙烯的性质和合成实验。人们不断探索各种改进方法,其中以五氧化二磷为脱水剂和无水乙醇作用制备乙烯的方法报道最多,影响也最广。笔者对该改进实验进行了研究,结果发现用五氧化二磷和无水乙醇作用制备乙烯的方法,在实验中难以得到乙烯,在理论上也缺乏足够的依据,本文就此提出自己的一点粗浅看法,与作者、读者讨论。     

提高乙醇与浓硫酸制乙烯产率的实验研究

我们知道,实验室用乙醇脱水制乙烯的反应主要利用了浓硫酸的强酸性,而副反应的发生是由浓硫酸的强氧化性引起的。笔者设想,对浓硫酸作适当稀释,使之既能保持其强酸性（即催化作用）,又能降低其氧化性,从而从根本上有效地减少副反应的发生,提高乙烯产率。为此,提出如下实验方案进行对比研究,寻找最佳稀释点。１实验方案及报告１．１实验装置（如图所示）１．２实验操作在烧瓶里,混合液按实验报告要求依次加入。加浓硫酸时,使烧瓶倾斜,沿瓶口缓慢倒入,塞上配有温度计和导管的橡皮塞,轻轻摇晃,使之混均,立即固定在铁架台上加热…     

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.     

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。     

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^-。     

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.     

解决能源问题的新途径——光解水制氢的研究

面对日益枯竭的能源危机,氢能是一种洁净、最有前景的替代能源。目前在各种制氢的方法中光催化分解水制氢的研究最多,光解水过程中催化剂最关键,本文对利用太阳能光解水的途径、提高光催化反应效率以及光催化剂的开发研究进行了综述。