Esters (A2) · 酯(A2)
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| ester/ˈestə/ | 酯 | zhǐ |
| acyl chloride/əˈkɪl ˈklɔːraɪd/ | 酰氯 | xiān lǜ |
| addition–elimination/əˈdɪʃn ɪˌlɪmɪˈneɪʃn/ | 加成消去 | jiā chéng xiāo qù |
| saponification/ˌsæpəˌnɪfɪˈkeɪʃn/ | 皂化 | zào huà |
| biodiesel/ˌbaɪəʊˈdiːzl/ | 生物柴油 | shēng wù chái yóu |
Esters 酯, revisited
- The smell of a pear, the tang of aspirin, the fat in your food — all are esters.
- An ester forms from an alcohol (or a phenol) joined to an acid group.
- The fast, reliable way to make one is with an acyl chloride 酰氯, at room temperature.
酯,再访
- 一个梨的气味、阿司匹林的味道、你食物中的脂肪——全都是酯。
- 一个酯由一个醇(或一个苯酚)连接到一个酸基团形成。
- 制造一个的快速、可靠方法是用一个酰氯,在室温下。
Ester A2 reaction map · 酯 A2 反应图谱
Compare ester formation, hydrolysis and transesterification routes. · 比较酯的形成、水解和酯交换途径。
An ester can be made at room temperature by reacting an acyl chloride with: · 一个酯可以在室温下通过把一个酰氯与以下反应制造:
Both alcohols and phenols react with acyl chlorides to give esters (+ HCl). · 醇和苯酚都与酰氯反应给出酯(+ HCl)。
Making an ester from an acyl chloride happens at room temperature. · 从一个酰氯制造一个酯在室温下发生。
Acyl chlorides are very reactive, so the reaction proceeds quickly at room temperature. · 酰氯非常活泼,所以反应在室温下快速进行。
An ester is hydrolysed by hot aqueous alkali in a reaction called ______. · 一个酯被热水性碱水解,在一个叫 ______ 的反应中。
It gives a carboxylate salt and an alcohol. · 它给出一个羧酸盐和一个醇。
Esters often have sweet, fruity smells. · 酯常常有甜的、果香的气味。
They are used as flavourings and perfumes. · 它们用作香精和香水。
Making esters
- alcohol/phenol + acyl chloride → ester + HCl — quick, and not reversible.
- The acyl chloride is so reactive it needs no catalyst and no heat.
- It works where a carboxylic acid is too slow — for example, esterifying an unreactive phenol.
Make ethyl ethanoate. Ethanol + ethanoyl chloride:
CH₃COCl + C₂H₅OH → CH₃COOC₂H₅ + HCl
The –OH of the alcohol attacks the C=O carbon; the chlorine leaves as HCl (an addition–elimination 加成消去). Name it from the alcohol part first (ethyl), then the acid part (ethanoate).
Aspirin is an ester of salicylic acid.
制造酯
- 醇/苯酚 + 酰氯 → 酯 + HCl——快速,且不可逆。
- 酰氯如此活泼,它不需要催化剂和热。
- 它在羧酸太慢的地方有效——例如,酯化一个不活泼的苯酚。
制造乙酸乙酯。 乙醇 + 乙酰氯:
CH₃COCl + C₂H₅OH → CH₃COOC₂H₅ + HCl
醇的 –OH 攻击 C=O 碳;氯作为 HCl 离开(一个加成—消去)。从醇部分(ethyl)先命名,然后酸部分(ethanoate)。
阿司匹林是水杨酸的一个酯。
Reacting phenol with benzoyl chloride gives: · 把苯酚与苯甲酰氯反应给出:
A phenol + an acyl (benzoyl) chloride forms the ester phenyl benzoate. · 一个苯酚 + 一个酰(苯甲酰)氯形成酯苯甲酸苯酯。
Hydrolysing an ester
- Hydrolysis is the reverse — water (or OH⁻) splits the ester back apart.
- Acid hydrolysis is reversible: you get the carboxylic acid + the alcohol back.
- Base hydrolysis (saponification 皂化) is one-way: you get a carboxylate salt + the alcohol.
Acid and base hydrolysis give different products. Acid → the carboxylic acid; base → the carboxylate salt (e.g. sodium ethanoate, not ethanoic acid). Base hydrolysis goes to completion because the salt cannot react back.
Hot KMnO4 oxidises a methyl side-chain to a COOH group
水解一个酯
- 水解是相反——水(或 OH⁻)把酯重新分开。
- 酸水解是可逆的:你得到羧酸 + 醇回来。
- 碱水解(皂化)是单向的:你得到一个羧酸盐 + 醇。
酸和碱水解给出不同的产物。酸 → 羧酸;碱 → 羧酸盐(例如乙酸钠,不是乙酸)。碱水解进行到完全,因为盐不能反应回去。
Esters all around us
- Small esters are volatile and sweet-smelling — used as flavourings, perfumes and solvents.
- Large esters make up fats and oils (esters of glycerol) and biodiesel 生物柴油.
- Saponification of a fat with NaOH is literally how soap is made.
我们周围的酯
- 小酯是挥发性的、气味甜——用作香精、香水和溶剂。
- 大酯构成脂肪和油(甘油的酯)和生物柴油。
- 用 NaOH 皂化一个脂肪就是肥皂制造的方式。
You've got it
- an ester forms from an alcohol or phenol + an acyl chloride (+ HCl), at room temperature
- name it alcohol-part + acid-part: ethanol + ethanoyl chloride → ethyl ethanoate
- acid hydrolysis (reversible) → acid + alcohol; base hydrolysis (one-way) → salt + alcohol
- esters are everywhere: fruit smells, aspirin, fats/oils, biodiesel, soap
你掌握了
- 一个酯由一个醇或苯酚 + 一个酰氯(+ HCl)形成,在室温下
- 命名它醇部分 + 酸部分:乙醇 + 乙酰氯 → 乙酸乙酯
- 酸水解(可逆)→ 酸 + 醇;碱水解(单向)→ 盐 + 醇
- 酯无处不在:水果气味、阿司匹林、脂肪/油、生物柴油、肥皂