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课程名称：有机化学 - 醇、酚与醚 课程概述：本课程介绍醇和酚的分类，主要基于羟基数量和羟基所连接的碳原子的杂化状态（sp3或sp2）；而醚则基于连接到氧原子的基团进行分类。醇的制备方法包括：（1）通过烯烃的水合反应（在酸性环境下）和（2）通过氢硼化-氧化反应；（3）从羰基化合物中制备，采用催化还原或格氏试剂的作用。酚的制备可通过（1）在卤代芳烃中用羟基代替卤素原子，或取代芳基磺酸中的磺酸基团；（2）通过重氮盐的水解，以及（3）工业上从 cumene 生产。 醇的沸点通常高于相同分子量的烃、醚和卤代烃。醇、酚和醚能够与水形成分子间氢键，从而使其在水中溶解。醇和酚具有酸性，酚中的电子吸引基团增强其酸性，而电子释放基团则降低其酸性。醇可以与氢卤酸进行亲核取代反应生成卤代烃，脱水反应则生成烯烃。醇在氧化反应中，初级醇可在温和氧化剂作用下氧化为醛，而在强氧化剂作用下氧化为羧酸；而次级醇则氧化为酮，三级醇对氧化反应具有耐受性。 酚因其羟基的存在，激活芳香环进行电亲核取代反应，并通过共振效应使新基团定向到邻位和对位。Reimer-Tiemann 反应可将酚转化为水杨醛。酚在氢氧化钠存在下生成的酚钠离子比酚更为活泼，因此在碱性介质中酚可以进行Kolbe反应。 醚的制备方法包括：（1）醇的脱水反应和（2）Williamson 合成。醚的沸点与烷烃相似，而其溶解度则与相同分子量的醇相当。醚中的C-O键可以被氢卤酸断裂。在电亲核取代反应中，醚中的烷氧基团可以激活芳香环，并使新基团定向到邻位和对位。 此课程适合希望深入了解醇、酚和醚化学特性及其反应机制的学生。
SUMMARYAlcohols and phenols are classified (i) on the basis of the number of hydroxyl groups and (ii) according to the hybridisation of the carbon atom, sp3 or sp2 to which the -OH group is attached. Ethers are classified on the basis of groups attached to the oxygen atomAlcohols may be prepared (1) by hydration of alkenes (i) in presence of an acid and (ii) by hydroboration-oxidation reaction (2) from carbonyl compounds by (i) catalytic reduction and (ii) the action of Grignard reagents. Phenols may be prepared by (1) substitution of (i) halogen atom in haloarenes and (ii) sulphonic acid group in aryl sulphonic acids, by -OH group (2) by hydrolysis of diazonium salts and (3) industrially from cumene.Alcohols are higher boiling than other classes of compounds, namely hydrocarbons, ethers and haloalkanes of comparable molecular masses. The ability of alcohols, phenols and ethers to form intermolecular hydrogen bonding with water makes them soluble in it.Alcohols and phenols are acidic in nature. Electron withdrawing groups in phenol increase its acidic strength and electron releasing groups decrease it.Alcohols undergo nucleophilic substitution with hydrogen halides to yield alkyl halides. Dehydration of alcohols gives alkenes. On oxidation, primary alcohols yield aldehydes with mild oxidising agents and carboxylic acids with strong oxidising agents while secondary alcohols yield ketones. Tertiary alcohols are resistant to oxidation.The presence of -OH group in phenols activates the aromatic ring towards electrophilic substitution and directs the incoming group to ortho and para positions due to resonance effect. Reimer-Tiemann reaction of phenol yields salicylaldehyde. In presence of sodium hydroxide, phenol generates phenoxide ion which is even more reactive than phenol. Thus, in alkaline medium, phenol undergoes Kolbe's reaction.Ethers may be prepared by (i) dehydration of alcohols and (ii) Williamson synthesis. The boiling points of ethers resemble those of alkanes while their solubility is comparable to those of alcohols having same molecular mass. The C-O bond in ethers can be cleaved by hydrogen halides. In electrophilic substitution, the alkoxy group activates the aromatic ring and directs the incoming group to ortho and para positions.
