Lab 1 A Diazotization—Coupling Reaction The Preparation实验13重氮化偶联反应制备.docVIP

下载本文档

11
0
约7.94千字
约 9页
2018-06-19 发布于福建
举报
版权申诉

Lab 1 A Diazotization—Coupling Reaction The Preparation实验13重氮化偶联反应制备.doc

1、有哪些信誉好的足球投注网站（book118）网站文档一经付费（服务费），不意味着购买了该文档的版权，仅供个人/单位学习、研究之用，不得用于商业用途，未经授权，严禁复制、发行、汇编、翻译或者网络传播等，侵权必究。。
2、本站所有内容均由合作方或网友上传，本站不对文档的完整性、权威性及其观点立场正确性做任何保证或承诺！文档内容仅供研究参考，付费前请自行鉴别。如您付费，意味着您自己接受本站规则且自行承担风险，本站不退款、不进行额外附加服务；查看《如何避免下载的几个坑》。如果您已付费下载过本站文档，您可以点击这里二次下载。
3、如文档侵犯商业秘密、侵犯著作权、侵犯人身权等，请点击“版权申诉”（推荐），也可以打举报电话：400-050-0827(电话支持时间：9:00-18:30)。
4、该文档为VIP文档，如果想要下载，成为VIP会员后，下载免费。
5、成为VIP后，下载本文档将扣除1次下载权益。下载后，不支持退款、换文档。如有疑问请联系我们。
6、成为VIP后，您将拥有八大权益，权益包括：VIP文档下载权益、阅读免打扰、文档格式转换、高级专利检索、专属身份标志、高级客服、多端互通、版权登记。
7、VIP文档为合作方或网友上传，每下载1次，网站将根据用户上传文档的质量评分、类型等，对文档贡献者给予高额补贴、流量扶持。如果你也想贡献VIP文档。上传文档

Lab 1 A Diazotization—Coupling Reaction The Preparation实验13重氮化偶联反应制备

A Diazotization—Coupling Reaction: The Preparation of Methyl Orange Formation of a diazonium ion Azote is an old word for nitrogen. Hence, the presence of azo in the name of a chemical implies that nitrogen is present in the structure. Therefore, diazo means two nitrogen atoms. When combined with onium, we have diazonium, which means two nitrogen atoms and a positive charge (i.e., N2+). Diazonium ions are produced when an aryl amine reacts with cold nitrous acid. Nitrous acid is unstable and is prepared just prior to its use by a reaction between sodium nitrite and hydrochloric acid. Figure 1 shows the conversion of aniline into the positive benzene diazonium ion. Figure 1. The diazotization of aniline. Substitution Reactions of Diazonium Ions A diazonium ion is the cation of a salt, and it is a reactive intermediate that undergoes substitution or coupling reactions. Table 1 shows some groups that may substitute for a diazo group bonded to an arene (ArN2+). Table 1. Groups that substitute for N2+ in ArN2+. Reagent Group Product CuBr (HBr) CuCl (HCl) CuCN (KCN) Br Cl CN ArBr ArCl ArCN KI I ArI Cu2O, Cu(NO3)2, H2O OH ArOH H3PO2 H ArH A generalized equation for a substitution reaction is shown below in which the reagent can be any reagent in Table 1 and X any group. Coupling Reactions of Diazonium Ions Compounds such as aniline and phenol, which contain strong electron donating groups (e.g., -OH and –NH2) that activate the ortho and para positions on a benzene ring, can undergo coupling reactions with a diazonium ion. A coupling reaction is one in which two aryl rings are joined by an azo group. These coupling reactions usually occur at the para position of the o,p director. Figure 2 shows the coupling of benzene diazonium ion with phenol at the para position of phenol. Figure 2. Coupling reaction with phenol. Aniline may serve as the substrate for the formation of a diazonium ion as shown in Figure 1, and it may serve as the substrate for a coupling reacti