应用化学专业英语 Lesson 28 翻译

Lesson 28 A Experiment Ease: Synthesis of

Salicylic Acid

From Oil of Wintergreen (Methyl

Salicylate)

overview

Methyl salicylate (水杨酸酯) (oil of wintergreen) and salicylic acid (水杨酸) are naturally occurring compounds with medicinal uses. You will try to prepare salicylic acid by boiling methyl salicylate with aqueous sodium

28课 一个实验案例：从冬青油（水杨酸酯）中合成水杨酸

概述

水杨酸酯（冬青油）和水杨酸是常用于药物合成的天然物质。你可以尝试煮沸含有氢氧化钠水溶液（(lye 碱液）的水杨酸酯制备水杨hydroxide(lye 碱液). You will also try to purify your product by recrystallization (再结晶) and characterize it by measuring its melting temperature.

Time require:2 laboratory sessions.

Background Methyl salicylate and salicylic acid are naturally occurring compounds with medicinal uses. The procedure used here to convert methyl salicylate into salicylic acid is called saponification (皂化) 。It is chemically related to the process used to convert natural fats into soap. Salicylic acid and aspirin Many plants produce salicylic acid naturally. Among these, willow trees (柳树) have been recognized since antiquity as a potent (有效) source of medicine. Hippocrates (一个希腊的名医) encouraged the pregnant women of ancient Greece to chew willow leaves and drink willow tea to alleviate (减轻) labor and birth pains. Chinese, Native Americans, and others also used willow. Salicylic acid is found mainly in the willo w’s leaves and bark (树皮).The pure acid possesses several useful medicinal properties. It is an antipyretic (a fever reducer), an analgesic (a pain reducer), and an anti-inflammatory (a swelling reducer). Unfortunately, pure salicylic acid and even the concoctions (混合物) derived from willow, make for an extremely unpleasant medicine. The salicylic acid molecule contains two acidic functional groups, the phenol group (PhOH) and the carboxylic acid group (-COOH). These groups make salicylic acid an irritating (刺激性的) substance that burns the sensitive linings of the mouth, throat, esophagus (食道) ， and stomach. [Interestingly, salicylic acid’s ability to burn living tissue 酸，你也可以通过重结晶提纯你的产品和通过测量它的熔解温度来描绘它的特性。

授课时数：2个实验课时

背景

水杨酸酯和水杨酸是常用于药物合成的天然物质。这里安吧水杨酸酯转化成水杨酸的过程叫做皂化。这是用化学方法和相关程序吧天然脂肪转化成肥皂。 水杨酸和阿司匹林

许多植物都能产生天然的水杨酸。其中，柳树从古代就被认为是有效的药物资源。古希腊的名医希波克拉底鼓励孕妇咀嚼柳叶与和柳叶泡的茶来减轻分娩和生产时的痛苦。中国人，印第安人和其他人也使用柳树。

水杨酸主要存在于柳树的叶子和树皮。这种纯酸占有几个重要的药物功能。它是一种退热药剂（一种退烧剂），一种镇痛剂（一种止痛药），一种抗炎药（一种消炎药）。

不幸的是，高纯度的水杨酸和混合物同时从柳树中分离出来，用于药物中极其不乐观。水杨酸分子包括2个酸性官能团，酚组团（苯酚）和羧酸官能团（羧酸）。这些官能团使水杨酸成为对烧伤敏感的口腔、呼吸道、食道和胃有刺激性的物质。[有趣的是，水杨酸可以燃烧活性组织的性能使它对其他应用很

makes it useful for other applications. Salicylic acid is the active ingredient in Compound W, an over-the-counter (不需处方课合法出售的) wart (疣) remover.]

The best way to mitigate (减轻)salicylic acid ’s harsh (令人生厌的) qualities is to replace the acidic hydrogens with less reactive groups of atoms. For example, replacing the phenolic hydrogen with an acetyl 有帮助。水杨酸是合成一种有效治愈疣的消除剂W 的有效组成部分。]

减轻水杨酸令人生厌的性质最好的办法是用酸性氢代替来减少反应的原子团。例如，用乙酰基–COCH 3, 代替酚醛酸得到乙酰水杨酸或“阿司匹林”。

group, –COCH 3, gives acetylsalicylic acid or “aspirin ”.

salicylic acetylsalicylic acid acid

Acetylsalicylic acid does not occur naturally. It contains only one acidic functional group, and bypass most of the digestive (消化的) system without causing burns. Eventually, acetylsalicylic acid reacts with water, mainly in the bloodstream to regenerate salicylic acid. Methyl salicylate

Methyl salicylate, like salicylic acid, is produced by many plants. It was first isolated from wintergreen leaves, Gaultheria(白株树属) procumbens, and is often called oil of wintergreen.

Methyl salicylate is similar to acetylsalicylic acid in that it masks one of the acidic hydrogens in salicylic acid. Methyl salicylate replaces the carboxylic acid hydrogen with a methyl group, –CH 3. The result is a relatively unreactive compound that does not liberate salicylic acid efficiently in the body. Consequently, methyl salicylate is not effective analgesic.

Methyl salicylate has other uses, including its distinctive fragrance (香味) ，and is added to many commercial products, including root beer (根汁汽水) and Ben-Gay ointment (油膏).

Pre-lab preparation

Notebook . This experiment involves a chemical preparation so you should set up your notebook according to the examples give in Padias and How-to Keep a Lab Notebook.

Your chemical equation should not be a mechanism. Rather, show the material you will start with

水杨酸 乙酰水杨酸

乙酰水杨酸不能天然生成。它只包含一个酸性官能团，不会导致烧伤地绕过大部分消化系统。乙酰水杨酸主要在流动的血液中与谁反应，最后还原成水杨酸。 水杨酸酯

水杨酸酯和水杨酸一样可以冲许多植物中提炼。它第一次是从白株树属类的冬青树叶中分离得到的，所以常被叫做冬青油。

水杨酸酯类似于乙酰水杨酸，是在于它掩盖了一个酸性氢水杨酸。水杨酸酯用一个甲基团–CH 3代替了羧酸氢，这使得一个相当难合成的反应无法在人体中有效释放出水杨酸。因此，水杨酸酯不是游戏的止痛剂。

水杨酸酯还有其他用途，包括它的独特香味和许多其他贸易产品的添加剂，如根汁汽水和Ben-Gay 油膏。

实验前期准备

笔记本。这个实验包含了一个化学制剂。所以你应该根据Padias 和《如何写实验笔记》给出的案例来建立你的笔记本。

你的化学反应式不应该仅有一个原理，而是更应该展示你一开

(methyl salicylate), important reagents (NaOH and H2O), important conditions (“reflux ”), and the product that you expect to get (salicylic acid). Do not draw anything else. Don ’t forget to include a table of physical properties for the substances that might appear in this experiment. This includes all starting materials, reagents, and produce. A sample table with “? ” indicating vital information is shown below.

始会使用的材料（水杨酸酯）、重要试剂（氢氧化钠和水），重要条件（“回流”），和你预期可得到的产物（水杨酸）。不需要引出其他物质。

别忘了列一张有关可能出现在试验中的物质的物理性质的表格，这包括所有的原料、试剂和产物。一个带有“？”的示例表指示了至关重要的信息如下。

Safety ﹠ Disposal . Wear gloves and goggles and carry

out all operations in a fume hood. These are standard operating procedures, but they are especially important in this experiment. Any other hazards and warning about safe handling should be entered un your notebook. Disposal procedures should also be entered for each reagent. Salicylic acid will be collected in a

special container.

Pre-lab activity. Before you come to lab, download the activity sheet and complete it. We will discuss your answers at the start of lab.

Reaction Equipment

50ml round bottom flask lab jack + stirring motor

magnetic stir bar

ceramic heater +controller

graduated cylinder screw clamps

reflux condenser ﹠ water hoses

funnel

disposable pipettes

安全处理。所有操作要在通风橱内执行并穿手套戴护目镜。这是标准的操作程序，但它们在这个实验中特别重要。其他任何关于安全处理的危险和警告都应该记录到你的笔记本里。程序处理也应该包括每种试剂，水杨酸应将被收集在一个特殊的容器中。 准备实验活动。在你进入实验室前，下载活动表并填完它。实验开始前我们会讨论你的答案。

反应 50ml 圆底烧瓶

实验插孔+搅拌电机 磁力搅拌器

陶瓷加热器+控制器 量筒 螺丝钳夹

回流冷凝器和软胶水管 漏斗

一次性吸量管

In your fume hood: place a stirring motor on top of a partially opened lab jack, then place a heater on top of the motor. Clamp the round bottom flask to the monkey bars (攀吊架) in your fume hood so that it rests in the heater. Plug the heater into the controller, but do not turn on the controller (never plug a heater directly into a wall socket). Transfer sufficient 6mol/L aqueous NaOH into a graduated cylinder so that you have 120mmol of NaOH, then transfer this liquid to the round bottom flask using a funnel. Record the volume of aqueous NaOH that you actually use. Rinse (漂洗) your funnel and graduated cylinder with water to remove all traces of the reagent, and remove any stray (零散的) drops of reagent from the ground-glass neck of your flask.

Transfer about 21mmol of methyl salicylate to your graduated cylinder. Record the volume that you actually use and transfer this material to the round bottom flask using a funnel. You should see a white gummy(黏性的) material form in your flask.

Equip the flask with a stir bar, reflux condenser, and water hoses. Slowly flow water though the reflux condenser and adjust the controller voltage to initiate reflux. Reflux the mixture for 30 minutes, while stirring as best you can (the gummy material prevent the stir bar from working at first, but the material soon dissolves). Turn off the controller and remove the lab jack, motor, and heater. Allow the mixture to cool temperature before cont

Workup

在你的通风橱里：把一个搅拌马达放在局部打开的使用插孔上，再把一个热器放在马达上。把圆底烧瓶固定在你通风橱内的攀吊架上，使它能紧贴着加热器。将插头接到控制器 上，但别打开控制器（千万别把加热器直接插入到墙上的电源插座里）。将足够的120mmol 的6mol/L氢氧化钠溶液转移到量筒中，在用漏斗把它转移到圆底烧瓶里，记录你实际使用的氢氧化钠溶液。用谁漂洗你的漏斗和量筒以除去残留的试剂，并消除你烧瓶玻璃瓶颈上的热呵呵零散的试剂液滴。

将约21mmol 的水杨酸酯转移到量筒中，再用漏斗把原料转移到圆底烧瓶中，记录你实际使用的量。你应该会看到烧瓶中有一种白色物质。

设备：带搅拌器的烧瓶、回流冷凝管及软胶水管。开始回流前，吧水缓缓通过冷凝管，校准电压控制器。让混合物回流30分钟，同时尽你最大的可能搅拌（搅拌开始时粘性物质会产生在搅拌器上，但会很快就熔解）。关掉控制器并分离开实验插孔、马达和加热器。在实验继续前让混合物先冷却至室温。

150ml 烧杯 PH 试纸

400ml 烧杯（水浴烧杯） 250ml 过滤瓶

150ml beaker pH paper

400ml beaker(for ice water bath) 250ml filtering flask

heavy-walled rubber hose

Buchner funnel +neoprene adaptor

Filter paper Pour the cooled mixture into a 150ml beaker. Add sufficient 3mol/L aqueous H2SO 4 to precipitate (使沉淀) all of the salicylic acid. Place the beaker in an ice-water bath for several minutes, then collect your product by vacuum filtration. While still applying a vacuum, rinse the solids with a small amount of ice-cold water and let then air-dry for several minutes.

Recrystallization

Two 250ml Erlenmeyer flasks Boiling chips

Hot plate (stirring motor)

Disposable pipers + rubber bulbs

厚壁橡胶软

布氏漏斗+氯丁橡胶适配器 滤纸

把冷却的混合液导入150ml 烧杯中。加入足量的3mol/L硫酸溶液时所有的水杨酸沉淀。把烧杯放在冰水浴中冷却几分钟，然后通过空抽气泵时用少量冰冷的水冲洗股日，然后再晾干几分钟。

重结晶 2个250ml 的锥形瓶 沸腾片

热板（搅拌器）

5~10ml的去离子水放在一个250ml 锥形瓶中（“酸液”瓶）。把约80~120ml的去离子水放在第二个烧瓶中（“水”溶液烧瓶）。每个烧瓶中加入2~3粒沸石。将“水”溶液烧瓶放在加热板上加热至沸。接着，把“酸”液烧瓶紧贴在“水”溶液烧瓶旁边放在加热板上，同样将“酸”混合液加热至沸。将“水”溶液烧瓶中足够的沸水倒入“酸”液烧瓶中，溶解所有的固体颗粒。把“酸”液烧瓶从加热板移开并慢慢冷却，水杨酸会自然结晶。

待物料完全冷却后，用真空抽气泵（使用干净的过滤瓶和漏斗）重复抽滤产物。将产物放在一个透明的玻璃容器内置于你实验室的干燥器里。

表征（第二周）

在你的产物至少干燥2小时候记录它的重量和熔解温度。

报告

在化学期刊201/202的所有使用中必须用实验报告来描述。实验报告必须像一个单独的文档那样出

Place your crude salicylic acid and 5~10ml of deionized water (去离子的水) in a 250ml.Erlenmeyer flask (“acid ” flask). Place about 80~120ml of deionized water in a second flask (“water ” flask).Add 2~3 boiling chips to each flask. Place the “water ” flask on a hot plate and bring the water to a boil. Next set the “acid ” flask next to the “water ” flask on the hot plate and bring the “acid ” mixture to a boil as well. Transfer just enough boiling water form the “water ” flask to the “acid ” flask to dissolve all of the solids in the ”acid ” flask. Remove the “acid ” flask from the hot place and let solution cool slowly. Salicylic acid should crystallize spontaneously (自然地).

After the solution has cooled sufficiently, recover

the produce by vacuum filtration (use a clean filter flask and funnel). Set the product on a watch glass inside your laboratory cabinet to dry.

Characterization (Week2)

After your product has dried for at least 12 hours,

record its weight and its melting temperature.

Report

All experiments in Chem 201/201 must be described by a

lab report. The lab report must be turned in as a separate document that follow the technical writing conventions used by organic chemists (the appendix How to Write Lab Report provides complete instructions for preparing a technically sound lab report ).

Because some of the writing conventions used in organic chemistry will seem strange [the passive voice(被动态),the repetition of some information, but not all, etc.], we have provided several sample reports for you to study 现如有机化学家专用的习惯性写作技术（附录《怎么写实验报告》为准备一个有技术的音像实验报告提供了完整的操作指南）。能熟练地书写报告课被人欣赏，但打印报告也是可接受的。

由于有机化学中使用的一些书写惯例看似很奇怪[被动态，重复的内容，不仅这些，还有很多。]，and learn from. Assuming your experiment went according to plan, you can prepare your reports by plagiarizing(剽窃) our samples, but you are permitted to copy only the material that accurately describes your work.

You will need to think carefully about each word, each number, and each symbol, in the sample report to make sure that these items accurately reflect your work. Do not trust (or copy) any numerical values that appear in the sample report. Do not trust (or copy) any of the literature references. ” Plagiarize ” does not mean “stop thinking ”.

To make this a genuine learning experience, you must write your report “from scratch (乱写) ”. If you can, neatly write your report by hand, but if you typing is easier, go ahead. If you choose to type do not copy-and-paste directly from this web page to your word processor. Do mot prepare an electronic file and share it with classmates. Etc. Etc. The standard operating procedures of Reed College (and scientific) ethics apply. You might enjoy reading a short essay that we have posted on the Honor Principle.

Sample Report

Synthesis of Salicylic Acid from Methyl

Salicylate

C. Diver

Tues Lab, Box 007

Abstract Salicylic acid was obtained from methyl salicylate in 78﹪yield . The product was identified by its melting point. Results and Discussion Salicylic acid was obtained in 78﹪yield by refluxing 所以我们提供一个示例报告给你们学习和参考。假设你的实验按计划安排来做，你可以借鉴我们的示例报告来准备你的报告，但你得承认只使用了精确描述你操作的原料。 你需要仔细思考每一个词汇，每一个数据，每一个符号，在一个示例报告中确保这些项目能准确反映你的操作。别依靠（或复制）任何已经出现在示例报告中的有效数值。也别依赖（或复制）任何文献参考值。“剽窃”并不意味着“停止思考”。

让这次成为一个真正的学习经验，你必须把你的实验报告脱离“乱写状态”。如果可以，熟练地手写你的报告，但若打印更容易，那就打吧。如果你选择了打印，别直接从网页上复制-黏贴到你的文字处理器中，也不需要准备一个电子文件和你的同学分享，等等。里德学院标准实验操作步骤是伦理的运用。你可以很享受地阅读一篇我们曾发表在“荣誉原则”的短文。

示例报告

从水杨酸酯中合成水杨酸

C. Diver

Tues Lab, Box 007

文摘

从水杨酸酯中获得水杨酸的产率为78﹪，通过它的熔解温度可以将产物分离出来。 结果讨论

通过回流水杨酸与氢氧化钠溶液的

methyl salicylate with aqueous NaOH. Recrystallization of the acid gave white needles, m.p.157~158.5℃(lit.159℃).

Experimental

Preparation of salicylic acid . Methyl Salicylate (4ml, 31mmol) and 2mol/L ap. NaOH (10ml, 20mmol) were refluxed for 30min. The solution was acidified with 6 mol/L aq. H2SO 4 (~25ml) and filtered. The crude product was recrystallized from boiling ethanol and dried for three 混合液可获得产率为78﹪的水杨酸。酸在熔点约157~158.5℃(燃点159℃) 温度下重结晶得到白色针状物。

实验

制备水杨酸。将4ml ，31mmol 的水杨酸酯和2mol/L 的氢氧化钠溶液（10ml ，20mml ）混合回流30分钟。再用6 mol/L的硫酸溶液酸化，过weeks to give green crystals of salicylic acid:3.33g (78％ from methyl slicylate), m. p. 157~158.5℃ (lit.159℃). References

1. Kaplan, R., ed. “Bob ’s Big Book of Chemicals”, 1 st

Ed., , XYZ P, New York, 1984.

E-factor

This experiment used the following materials: methyl slicylate (3g), NaOH(3g), sulfuric acid (4g), ethanol (40g);total consumables (50g). The product (3.33g) does not count as waste; total disposables (46.7g). E-factor=14.

Post-report question

(Because this section does not involve copying phrases from the sample report, feel free to 1) type this section and 2) copy material from the Journal electronically).

Please attach the title and abstract from a recently published article in the Journal of Organic Chemistry to your report (electronic copy-and-paste is perfectly acceptable here). The journal is available online though the synthesis of an organic molecule (the word “synthesis ” will probably appear in the article’s title).

Cite the article so that I know which one you are looking at. Then provide brief answer to the following question:1) To what extent do the title and abstract comply with the standards set out by the Journal of Organic Chemistry ’s guidelines? (see How to Write Lab Reports for a short version of these guidelines), 2) In what ways does the information in the abstract supplement/extend the information found in the title? 3) In what way(s) does the information in the body of the article supplement/extend the information found in the abstract? Just pay attention to information that relates to the synthesis. Don’t bother with other parts of the article. Exercises

Try to write a English chemical experiment report

滤，原油产物从沸腾的乙醇中重结晶，接着干燥3周，得到高纯度的水杨酸晶体：3.33克（从水杨酸酯中获得78﹪的产率）。

参考文献

1. Kaplan, R.，等.1984年纽约xyz

新闻发表的“鲍勃化学大全”第一版。 影响因素

这个实验使用以下材料：水杨酸酯（3克），氢氧化钠（3克），硫酸（4克），乙醇（40克）；总耗材（50克）。产物（3.33克）并没有包括浪费的；一次性用品共计（46.7克）。影响力=14。

邮报报告问题

（因为这部分不需要从示例报告中复制短语，随时可以1）打好这一节和2）从电子杂志中复印材料。）

将你的实验报告联系近几年发表在“有机化学”的一篇电子文章的题目和摘要（电子复制-黏贴在这里是完全可以接受的）。这本杂志通过芦苇图书馆的网站发表在网络上，任何长度的文章只要有关于合成有机原子（“合成”一次完全可以出现在文章的题目中）的题目和摘要信息都可以通过这里发表。

让我了解在你引用了文章的哪些内容，然后提供以下问题的可信答案：1）在何种程度上标题和摘要符合发表在“有机化学”杂志指南的标准吗？（参阅《如何写实验报告》而来的简短版本的指南），2）在哪些方面可以抽象的补充∕扩展

according to a laboratory text.

标题的信息呢？3）以何种方式不会在人体文章的补充/扩展信息中发现的抽象信息？只要注意涉及合成信息，不要涉及文章的其他部分。 练习

根据一个实验文本尝试也一篇英文化学实验报告。