H Solubility H-bond H3C CH3 Good sovent foracoh(Fig.2.Intermolecular hydrogen bonding of a ketone with water. Lone pair of electrons on oxygen of carbonyl can accept a hydrogen bond from O-H or N-H. Low molecular weight aldehydes and ketones (e.g.formaldehyde and acetone)are soluble in water. large molecular weight aldehydes and ketones are insoluble in water. Aromatic ketones and aldehydes are insoluble in water due to the hydrophobic aromatic ring. Acetone and acetaldehyde are miscible in water
Solubility ◼Good solvent for alcohols. ◼Lone pair of electrons on oxygen of carbonyl can accept a hydrogen bond from O-H or N-H. ◼Low molecular weight aldehydes and ketones (e.g. formaldehyde and acetone) are soluble in water. ◼large molecular weight aldehydes and ketones are insoluble in water. ◼Aromatic ketones and aldehydes are insoluble in water due to the hydrophobic aromatic ring. ◼Acetone and acetaldehyde are miscible in water
Formaldehyde Gas at room temperature. Formalin is a 40%aqueous solution. H HO _H 0→ OH H-C >H formaldehyde, b.p.-21C formalin trioxane,m.p.62C
Formaldehyde ◼Gas at room temperature. ◼Formalin is a 40% aqueous solution. O C O C O C H H H H H H heat H C O H H2O H C H OH HO trioxane, m.p. 62C formaldehyde, b.p. -21C formalin
自秋转大寺 Industrial Importance Acetone and methyl ethyl ketone are important solvents. Formaldehyde used in polymers like Bakelite®.胶木 Flavorings and additives like vanilla, cinnamon,artificial butter
Industrial Importance ◼Acetone and methyl ethyl ketone are important solvents. ◼Formaldehyde used in polymers like Bakelite. ◼Flavorings and additives like vanilla, cinnamon, artificial butter. 胶木
Tautomers R H B 互变异构体， Keto tautomer Enol tautomer 酸碱对烯醇式都 ⊕ 有促进作用 Step 1 Step 2 CH ⊙
互变异构体 ， 酸碱对烯醇式都 有促进作用 Tautomers O O O H O CH O O O H O O H O O O O H O CH O O O H O O H O
结构对烯醇型含量的影响 名称 化合物结构 烯醇型含量 0 丙酮 CH;CCH3 2.4X104 环己酮 2.00X10-2 00 乙酰乙酸乙酯 CH:CCH2COC2Hs 7.5 00 苯甲酰乙酸乙酯 CCH2COC2H5 21 00 乙酰丙酮 CH.CCH2CCH3 80 00 苯甲酰丙酮 CCH2CCH 99
结构对烯醇型含量的影响 名称 化合物结构 烯醇型含量 丙酮 环己酮 乙酰乙酸乙酯 苯甲酰乙酸乙酯 乙酰丙酮 苯甲酰丙酮 CH3CCH3 O O CH3CCH2COC2H5 O O CCH2COC2H5 O O CH3CCH2CCH3 O O CCH2CCH3 O O 2.4X10 -4 2.00X10 -2 7.5 21 80 99