1.Review the fundamental operations of organic experiment, such as simple distillation, recrystallization and the determination of melting point. 2.Be familiar with physicochemical properties of the reagents and learn to design the procedures according to references to obtain 4-aminobenzoic acid from 4-nitrotoluene. 3.Determine the products of every step by TLC, IR, melting point determination or 1HNMR, and learn to analyze the results to testify the efficiency and the validity of the experiments. |
The chemical reactions are showed in the following: Aromatic carboxylic acids are often prepared by oxidation of aromatic side chains. The aromatic ring of aromatic hydrocarbons is relatively stable and difficult to oxidize, and the chain of the ring regardless of length, as long as it has α-H, in the strong oxidation, it will finally be oxidized to carboxyl groups. The laboratory generally oxidizes toluene by potassium permanganate to produce benzoic acid Since toluene is insoluble in potassium permanganate aqueous solution, the reaction is a two-pha reaction, so the reaction needs to be sufficiently stirred and refluxed at a higher temperature for a relatively long period of time. After heating and refluxing, the potassium salt of the benzoic acid and the precipitation of mangane dioxide are obtained in the first place. The precipitate is parated and the potassium salt of the benzoic acid is acidified with hydrochloric acid to obtain benzoic acid, which is hardly soluble in water and crystallized easily. The reduction of nitro group can be done by Fe powder with acetate or Sn powder with condend HCl. Fe is much cheaper but the yield is lower, so we choo to u Sn as reductant. As a matter of fact, the Sn salt of amino benzoic acid is toxic and needs special care to prevent skin exposure and inhalation. |
名称 | 分子量 | 性状 | 折光率 | 比重 | 熔点（oC） | 沸点（oC） | 溶解度（克/100ml溶剂） | ||
水 | 醇 | 醚 | |||||||
4-nitrotoluene | 137.1378 | 信的书写格式 Yellow oblique facade crystal | 1.5382 | 南宁话 1.29 | 低功耗显卡51.7 | 238.5 | insoluble | Readily soluble | Readily soluble |
4-nitrobenzoic acid | 167.13 | Yellow or white oblique facade crystal | unknown | 1.610 | 239~241 | unknown | <0.1g | soluble | soluble |
4-aminobenzoic acid | 137.14 | 提前英文Colorless needle-like crystal | 1.374（25℃） | 187~187.5 | unknown | Readily soluble(hot) sparingly soluble(cold) | Readily soluble | Readily soluble | |
试剂名称 | 用量 | 规格 | 试剂名称 | 用量 | 规格 | |||
4-nitrotoluene | 2.5g | A.R. | ligroin | 20ml | 60-90 oC | |||
| 12.5g | A.R. | NaOH (aq) | 20ml | 50% | |||
Sulfuric acid | 7.5ml | condend | Ethyl acetate | 20ml | A.R. | |||
Sn | 4g | powder | ammonia water | 30ml | condend | |||
Hydrochloric acid | 15ml | condend | cyclohexane | 30ml | A.R. | |||
ethanol | 20ml | A.R. | ||||||
| 胃病的症状 | ||||||||
| 小班美工教案 |
Time | synthesis | characterization |
WEEK1 | Oxidation of 4-nitrotoluene | |
WEEK2 | Purification | m.p. determination, TLC IR |
厚道WEEK3 | Reduction of 4-nitrobenzoic acid | |
WEEK4 | Purification | H-NMR |
WEEK5 | IR | |
本文发布于:2023-05-22 11:48:35，感谢您对本站的认可！
本文链接：https://www.wtabcd.cn/fanwen/fan/89/923405.html
版权声明：本站内容均来自互联网，仅供演示用，请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系，我们将在24小时内删除。
| 留言与评论（共有 0 条评论） |
