Investigating a Reaction of N-Methyltriazolinedione

This undergraduate laboratory experiment challenges students to use their combined knowledge of organic reaction mechanisms and spectroscopic analysis to determine the product of a reaction that has several possible outcomes. The result is that students gain the real-life experience, commonly encountered by most research chemists, of characterizing and identifying an unknown organic substance.     

A Chemiluminescent Clock Reaction: A Dramatic Illustration of Competing Reaction Kinetics

In the presence of both rubrene and perylene dissolved in hexanes, oxalyl chloride and hydrogen peroxide react to generate three different colors of light in the order yellow, then white, and finally blue. Student observers with additional TLC data can develop a simple kinetics model involving competing fluorescer decomposition and emission events.     

Kinetics of Electrochemical Processes under Conditions of a Slow Chemical Reaction in Solution

The kinetics of electrochemical processes under the conditions of a slow chemical reaction in solution is analyzed in a general form, which admits a change in their limiting stages. The main feature of polarization curves for the electrochemical processes is the existence of two Tafel portions with slopes corresponding to a slow homogeneous chemical reaction (lower portion) and a preceding faster electrochemical stage (upper portion with a higher slope).     

Self-Catalyzed Hydroxyl-Yne Click Reaction: A Powerful Tool toward Red-Emitting Nontraditional Small Organic Luminogens

Nontraditional small organic luminogens (NTSOLs) without classic conjugated chromophores have attracted significant attention. However, the design and synthesis of NTSOLs with fluorescence in the red region remain significantly challenging. In this study, we established a self-catalyzed hydroxyl-yne click reaction for preparing long-wavelength and red-emitting NTSOLs. Owing to their perfect reaction selectivity, high efficiency, and excellent universality, a series of compounds with well-defined structures were obtained in high yields. Moreover, the obtained compounds showed concentration-enhanced and excitation-dependent emission characteristics. The compounds also exhibited dramatical chemical structure-dependent and aggregation-induced red-shifted fluorescence properties, based on which we successfully obtained red-emitting NTSOLs by simply adjusting chemical structure and concentration. Also, the compounds show good cell staining ability, which can be used in cell imaging.     

化学反应动力学在有机合成条件优化中的应用

影响有机合成选择性和收率的因素主要包括反应机理、反应温度、立体效应、副反应等。由于缺乏相关数据和方法,一般很难对反应的影响因素（如溶剂和反应温度）进行理论预测,这使得合成路线的优化非常繁琐耗时。本论文基于反应的可能机理,在估算活化能的基础上,利用物理化学原理对温度的影响进行了讨论。结果表明,运用物理化学原理进行简单分析即可对有机合成路线的优化提供有益的理论指导。     

Evaluation of the Use of A Laboratory Robot in a Study of Esterification Kinetics

Abstract

While the use of robots in routine quality-control and sample-preparation procedures is well established, their use in the research laboratory has not received as much attention. In order to evaluate the performance of laboratory robots in investigating problems that are non-routine and slightly more difficult, a Zymate-I robot was adapted to investigate the kinetics of two well-characterized reactions. The problems encountered and the need for verification devices in laboratory robotics are discussed.     

A Chemical Reaction to the Historiography of Biology

This article examines the often-overlooked role of chemical ideas and practices in the history of modern biology. The first section analyses how the conventional histories of the life sciences have, through the twentieth century, come to focus nearly exclusively on evolutionary theory and genetics, and why this storyline is inadequate. The second section elaborates on what the restricted neo-Darwinian history of biology misses, noting a variety of episodes in the history of biology that relied on developments in – or tools from – chemistry, including an example from the author’s own work. The diverse ways in which biologists have used chemical approaches often relate to the concrete, infrastructural side of research; a more inclusive history thus also connects to a historiography of materials and objects in science.     

微量反应系统化学动力学教学实验的设计与应用

利用光纤光谱仪构建微量反应系统,并通过偶氮染料橙黄II在铁-亚硫酸钠-溶解氧体系中的脱色反应,分别用特征动力学方程法及初始速率法进行了脱色反应动力学分析。该实验体系能够实现简单、快速的均相溶液反应动力学实验,其数据处理方法较好地巩固和提升了对反应动力学理论课教学内容的学习。整个实验体系的设计与应用能够满足物理化学、大学化学、环境化学等相关课程中有关反应动力学的实验教学需求。     

热效应对化学反应的影响

2 种单质间发生反应生成二元化合物大都是释热过程。本文讨论热效应对后续反应的影响。     

Thermal Diffusion with Chemical Reaction: A Carrier System

The heat of transport of oxygen across a membrane mediated by hemoglobin (Hb) as a carrier is iuvestigated by the method of irreversible thermodynamics. It is assumed that oxygen combines with hemoglobin molecules to form oxyhemoglobin according to the reaction nO₂ + Hb=HbO_zn. The oxyhemoglobin molecule HbO_zn then migrates to a new position and is reconverted to Hb by releasing oxygen. It is shown that the heat of transport of oxygen consists of two contributions; one due to the reaction and the other from thermal diffusion of individual species present. Total oxygen flux across the membrane is also calculated in terms of temperature and the chemical potential difference of oxygen across the membrane. The use of the heat of transport as a measure of the efficiency of the heat pump for the carrier-mediated transport process is investigated.     

Investigating a Boronate-Affinity-Guided Acylation Reaction for Labelling Native Antibodies

The excellent molecular recognition capabilities of monoclonal antibodies (mAbs) have opened up exciting opportunities for biotherapeutic discovery. Taking advantage of the full potential of this tool necessitates affinity ligands capable of conjugating directly with small molecules to a defined degree of biorthogonality, especially when modifying natural Abs. Herein, a bioorthogonal boronate-affinity-based Ab ligand featuring a 4-(dimethylamino)pyridine and an S-aryl thioester to label full-length Abs is reported. The photoactivatable linker in the acyl donor facilitated purification of azide-labelled Ab (N₃-Ab) was quantitatively cleaved upon brief exposure to UV light while retaining the original Ab activity. Click reactions enabled the precise addition of biotin, a fluorophore, and a pharmacological agent to the purified N₃-Abs. The resulting immunoconjugate showed selectivity against targeted cells. Bioorthogonal traceless design and reagentless purification allow this strategy to be a powerful tool to engineer native antibodies amenable to therapeutic intervention.     

维生素B1对B-Z振荡反应的影响及反应动力学

维生素是生物生长和代谢所必需的微量有机物,和激素相似,需要量很小,但对生命活动却有重要作用,缺少维生素生物会不能正常生长,甚至发生疾病．本文研究了维生素BI（以下简称VitBl）对B－Z振荡反应的影响,对揭示生命的奥秘,推动医学、药学等方面的研究发展将有一定帮助·实验结果表明,不同VitBI的浓度与振荡周期改变值凸t。及振幅改变值凸A均有良好的线性关系．线性范围为5．1（）X10－’～2．78X10－‘11。of·L－‘,相关系数分别为0．905和0．993．据此可为VitBl的定是分析测试提供信息及依据．1实验1．1仪器与试剂＊SS（…     

Reaction Kinetics of Dehydrochlorination of the Chlorohydrin Esters of Bisphenol A

Kinetics and Catalysis - The results of a study of the reaction kinetics of dehydrochlorination of the chlorohydrin esters of bisphenol A in the production of ED-20 epoxy resin are reported. The...     

科研转化的综合化学实验:银纳米粒子的制备及其催化反应动力学测量

设计了一个包含胶体化学方法制备金属纳米粒子及其作为异相催化剂催化氧化还原反应的动力学过程等内容的本科生综合化学实验。首先采用晶种生长法合成了不同尺寸的球状和片状银纳米粒子,然后经过离心纯化后作为异相催化剂催化硼氢化钠还原4-硝基苯酚的反应,研究了催化反应动力学过程,分析了催化反应的表观反应速率常数和催化剂的活性。本实验可以锻炼学生制备纳米材料和跟踪反应动力学进程的能力,使学生进一步理解异相催化反应机理、熟悉光谱仪器的应用。     

Mechanism and Kinetics of the Reaction of Nitrosamines with OH Radical: A Theoretical Study

The reaction of nitrosodimethylamine, nitrosoazetidine, nitrosopyrrolidine, and nitrosopiperidine with the hydroxyl radical has been studied using electronic structure calculations in gas and aqueous phases. The rate constant was calculated using variational transition state theory. The reactions are initiated by H‐atom abstraction from the αC─H group of nitrosamines and leads to the formation of alkyl radical intermediate. In the subsequent reactions, the initially formed alkyl radical intermediate reacts with O₂ forming a peroxy radical. The reaction of peroxy radical with other atmospheric oxidants, such as HO₂ and NO radicals, is studied. The structures of the reactive species were optimized by using the density functional theory methods, such as M06‐2X, MPW1K, and BHandHLYP, and hybrid methods G3B3. The single‐point energy calculations were also performed at CCSD(T)/6‐311+G(d,p)// M062X/6‐311+G(d,p) level. The calculated thermodynamical parameters show that the reactions corresponding to the formation of intermediates and products are highly exothermic. We have calculated the rate constant for the initial H‐atom abstraction and subsequent favorable secondary reactions using canonical variational transition state theory over the temperature range of 150–400 K. The calculated rate constant for initial H‐atom abstraction reaction is ∼3 × 10⁻¹² cm³ molecule⁻¹ s⁻¹ and is in agreement with the previous experimental results. The calculated thermochemical data and rate constants show that the reaction profile and kinetics of the reactions are less dependent on the number of methyl groups present in the nitrosoamines. Furthermore, it has been found that the atmospheric lifetime of nitrosamines is around 5 days in the normal atmospheric OH concentration.     

Kinetics and Mechanism of the Pudovik Reaction

Abstract

The kinetics and the mechanism of the Pudovik reaction for the series of α, β-unsaturated carbonyl compounds have been studied. The factors which determine the addition locoselectivity and the reactivity of the hydrophosphoryl and unsaturated compounds in this process are established. The qualitative and quantitative relationships obtained allow to predict the reaction rate and its direction depending on the reagents structure and also on the nature of catalyst and solvent used.     

A New Laboratory Experiment Based on a Chemical Transformation of Santonin: Synthesis of Santonic Acid

In this paper we describe a new comprehensive laboratory experiment based on a chemical transformation of santonin. The experiment is designed as a puzzle-solving exercise for advanced undergraduate organic chemistry courses and consists of the structure elucidation of santonic acid, the product obtained by the action of strong alkalis on santonin. An enquiry-based approach helps the students achieve this goal by combining their knowledge of organic chemistry and spectroscopy together with mechanistic thinking.     

Kinetics and Mechanism of the Kabachnic-Fields Reaction

Abstract

The Kabachnic-Fields reaction is one of the most important methods of synthesis of functionally substituted derivatives of tetracoordinated phosphorus with P-C bond. At the same time mechanism of this important and interesting reaction practically has not been investigated.