科学堂

选择适当的展开剂是首要任务.一般常用溶剂按照极性从小到大的顺序排列大概为：石油迷<己烷<四氯化碳<二硫化碳<甲苯<苯<二氯甲烷<三氯甲烷<乙醚

Petroleum ether/Ethylacetate，petroleum ether/Acetone，Petroleum ether/Ether, Petroleum ether/CH2Cl2, ethylacetate/MeOH,CHCl3/ethylacetate

　　展开剂的比例要靠尝试.一般根据文献中报道的该类化合物用什么样的展开剂，就首先尝试使用该类展开剂，然后不断尝试比例，直到找到一个分离效果好的展开剂。展开剂的选择条件：①对所需成分有良好的溶解性；②可使成分间分开；③待测组分的Rf在0.2~0.8之间，定量测定在0.3～0.5之间；④不与待测组分或吸附剂发生化学反应；⑤沸点适中，黏度较小；⑥展开后组分斑点圆且集中；⑦混合溶剂最好用新鲜配制。

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科学堂先前曾介绍过常用溶剂的溶度参数及溶剂对聚合物溶解能力的判定方法和常用溶剂的沸点、溶解性和毒性，使大家对一些常用溶剂的物理特性有了一些基本了解，今天科学堂将向大家介绍常用有机溶剂极性及混合溶剂极性顺序，且在给出其极性的同时，还给出了有机溶剂相应的粘度、沸点及吸收波长，希望对大家能有所帮助。

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学有机化学的人对NMR一定很熟悉,我们也要经常要碰到解析NMR谱图。那就一定会碰到溶剂峰。本人在解析谱图时也碰到这些问题。所以把NMR中经常碰到的溶剂峰的数据整理了一下。

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All of the animations listed below are used in association with the General, Organic and Biochemistry Course. They are in PDF format.

Chapter One

Accuracy

Precision

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The following problems are meant to be useful study tools for students involved in most undergraduate organic chemistry courses. The problems have been color-coded to indicate whether they are:

1. Generally useful,

2. Most likely to be useful to students in year long, rather than survey courses,

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This web collects some useful links to organic chemistry class web sites. Additionally, the author, Steven A. Hardinge, University Distinguished Lecturer in Organic Chemistry, gives simple illustration of them as well as his review of some pages.

VOH Archives at UCLA Old exams, class handouts, etc. A useful source of practice exams.

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The site will consist of essentially three sections per chapter:

1. Tutorial materials

2. Worked and Practice problems

3. On-line assessments

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The page was prepared by Dr Donald Robertson for organic chemistry experiments. It descrbes how to use ChemDraw and Chem3D. It also gives detailed information about several organic experiments, such as, Fischer esterification – preparation of isopentyl acetate (isoamyl acetate); hydrolysis of methylsalicylate and synthesis of acetylsalicylic acid; Williamson ether synthesis; aldol condensation; aromatic side chain oxidation – o-chlorobenzoic acid from o-chlorotoluene; preparation of N,N-diethyl-m-toluamide; synthesis of p-(4-nitrobenzeneazo)-N,N-dimethylaniline; and preparation of m-aminoacetophenone.

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1. 化合物毒性相关数据库 Toxnet http://toxnet.nlm.nih.gov/

2. 毒性物质与健康和环境数据库 http://esc.syrres.com/efdb/TSCATS.htm

3. 急性毒性数据库 http://www.cerc.usgs.gov/data/acute/acute.html

4. SpectraOnline,Galact http://spectra.galactic.com/SpectraOnline/Default_ie.htm

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The sites here cover detailed good materials for Molecular Modelling for Organic Chemistry. Its main content includes:

Introduction|Overview| Case Studies|Visualisation| Mechanics|MO Reactants|MO Transition State| MO Composite|Problems|Software

该课程由Henry Rzepa讲授。

Importance of Molecular Modelling

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