双语化学辞典Chem Lexicon
反应 · 有机化学 · 反应类型 Organic chemistry · Reaction types

缩合反应Condensation reaction

拼音Pinyin suō hé fǎn yìng　别名Also 缩合； condensation

定义Definition

缩合反应是两个（或多个）分子结合成一个较大分子，同时放出水、醇、氯化氢等小分子的反应。重复进行的缩合即缩聚，可生成高分子。

A condensation reaction joins two (or more) molecules into a larger one with loss of a small molecule such as water, an alcohol or HCl. Repeated condensation (polycondensation) gives polymers.

有机缩合Organic condensations

羟醛缩合（醛酮，失水）；克莱森缩合（酯，失醇）；诺文纳格尔、珀金缩合；酯化与酰胺化（失水）；亚胺、腙、肟的生成（羰基与氨衍生物失水）。

Aldol (aldehydes/ketones, losing water), Claisen (esters, losing alcohol), Knoevenagel and Perkin condensations, esterification and amidation (losing water), and imine, hydrazone and oxime formation.

缩聚Polycondensation

二元酸与二元醇或二元胺缩聚得聚酯、聚酰胺（尼龙）；苯酚与甲醛缩聚得酚醛树脂（贝克兰，1907，第一种全合成塑料）；硅醇缩合得有机硅。缩聚遵循逐步聚合规律（卡罗瑟斯方程）。

Diacids with diols or diamines give polyesters and polyamides (nylon); phenol and formaldehyde give Bakelite (Baekeland 1907, the first fully synthetic plastic); silanols condense to silicones. Polycondensation follows step-growth kinetics (Carothers).

生物缩合Biological condensations

氨基酸 → 蛋白质（肽键）、单糖 → 多糖（糖苷键）、核苷酸 → 核酸（磷酸二酯键）都是脱水缩合，由酶和 ATP 驱动；其逆过程为水解。

Amino acids → proteins (peptide bonds), sugars → polysaccharides (glycosidic bonds) and nucleotides → nucleic acids (phosphodiester bonds) are enzyme- and ATP-driven dehydrative condensations; the reverse is hydrolysis.

反应Reactions

A–H + HO–B ⟶ A–B + H2O

酸或碱催化，常需除去小分子推动平衡

Acid or base catalysis, often with removal of the small molecule

  1. 两个分子的官能团互相加成。

    Functional groups of two molecules add together.

  2. 消除小分子形成新键。

    Loss of a small molecule forms the new bond.

n HOOC(CH2)4COOH + n H2N(CH2)6NH2 ⟶ 尼龙-66 + 2n H2On HOOC(CH2)4COOH + n H2N(CH2)6NH2 ⟶ Nylon-66 + 2n H2O

缩聚制尼龙。

Polycondensation to nylon.

反应机理图Mechanism

红色弯箭头表示一对电子的移动方向：从电子来源（孤对电子或化学键）指向电子去向。Red curly arrows show where an electron pair moves: from its source (lone pair or bond) to its destination.

1

羰基氧质子化，羰基碳更亲电

Protonating the carbonyl O makes the carbon more electrophilic

2

乙醇进攻羰基碳

Ethanol attacks the carbonyl carbon

质子转移H⁺ shift
3

水作为离去基团离开

Water leaves

4

去质子化，催化剂再生

Deprotonation regenerates the catalyst

5

乙酸乙酯；每一步都可逆

Ethyl acetate; every step is reversible

年表Timeline

  • 1872

    武尔茨与博罗金发现羟醛反应

    Wurtz and Borodin discover the aldol reaction

  • 1907

    贝克兰发明酚醛树脂

    Baekeland invents Bakelite

  • 1935

    卡罗瑟斯合成尼龙-66

    Carothers makes nylon-6,6