中山大学：《有机化学》课程教学资源（课件讲稿）第十七章 脂 Lipids

第十七章 Lipids

第十七章 脂 Lipids

本章主要内容 甘油酯 磷脂 固醇类化合物 四.萜类化合物

本章主要内容 一．甘油酯 二．磷脂 三．固醇类化合物 四．萜类化合物

Lipids Lipids are organic compounds found in living organisms, that are soluble in nonpolar organic solvents Lipids have a variety of structures and functions

Lipids z Lipids are organic compounds found in living organisms, that are soluble in nonpolar organic solvents. z Lipids have a variety of structures and functions

Lipids AF (waxes)=R, CooR2, R=C16-C363R2" C16-C34 (保护及其他特殊功能) 甘油酯( glycerides)=甘油+脂肪酸 (储存能量) 磷脂( phospholipids)=甘油等+脂肪酸十磷酸十其他 (生物膜主要结构成分) 固醇类( steroids)(激素等功用) 类脂{前列腺素类( prostaglandins(多种系统调节作用) 萜类( terpenoids))(多种用途)

Lipids 蜡 (waxes) ＝ R1COOR2, R1= C16~C36, R2= C16~C34 （保护及其他特殊功能） 脂 甘油酯 (glycerides) ＝ 甘油+脂肪酸 （储存能量） 磷脂 (phospholipids) ＝ 甘油等＋脂肪酸＋磷酸＋其他 （生物膜主要结构成分） 固醇类 (steroids) （激素等功用） 前列腺素类 (prostaglandins) （多种系统调节作用) 萜类 (terpenoids) （多种用途） 类脂

CH,OH CHC=O COOH HH OH PGE cortisone vasodilator a hormone CHOH vitamin A limonene a vitamin in orange and oIIs CH-O 0-CH tAearin a fat

甘油酯Gy cerides 1 Structure CH2-OH R-C—0H cH2-0-c-R1 cH—OH R1-C-OH cH—0→c-F R CH,OH Ri-C-OH CH2-o-C-R 3 glycerol fatty acids triacylglycerol or triglyceride a fat or an oil O R1R2=R3, simple triacylglycerol R,R23 are not same, mixed triacylglycerol Fat: solid and semisolid; oils; liquid

一、甘油酯 Glycerides 1. Structure CH2 CH CH2 OH OH OH R1 C OH O R1 C OH O R1 C OH O CH2 CH CH2 O O O C C C O O O R1 R2 R3 glycerol fatty acids triacylglycerol or triglyceride a fat or an oil z R1=R2=R3, simple triacylglycerol z R1, R2, R3 are not same, mixed triacylglycerol z Fat: solid and semisolid; Oils: liquid

甘油酯 Glycerides 2. Fatty acid o Carboxylic acids with long hydrocarbon chains o Saturared and unsaturated fatty acids C4-C24, even number of c, unbranched Double bond positions: C-9-C-10 Double bond configuration: Z o Melting point: Saturated> unsaturated o more double bond, lower melting point

一、甘油酯 Glycerides 2. Fatty acid z Carboxylic acids with long hydrocarbon chains. z Saturared and unsaturated fatty acids z C4~C24, even number of C, unbranched z Double bond positions: C-9 ~ C-10 z Double bond configuration: Z z Melting point: Saturated > unsaturated z more double bond, lower melting point

TABLE 24.1 Common Naturally Occurring Fatty Acids Number Common Systematic name Structure Melting of carbons name point Saturated lauric acid dodecanoic acid myristic acid tetradecanoic acid COOH 58 palmitic acid hexadecanoic acid COOH 63 stearic acid octadecanoic acid COOH 69 arachidic acid eicosanoic acid COOH 77 Unsaturated palmitoleic acid (9Z)-hexadecenoic acid COOH 0 18 oleic acid (9Z)-octadecenoic acid COOH linoleic acid (9Z, 12Z)-octadecadienoic acid COOH linolenic acid (9z, 12Z, 152)-octadecatrienoic acid COOH -l1 arachidonic acid (5Z, 8Z, 11Z, 14Z)-eicosatetraenoic acid COOH 50 EPA (5Z, 8Z, 11Z, 14Z, 17Z)-eicosapentaeneoic acid COOH -50

甘油酯 Glycerides 3. Properties 熔点的高低主要决定于脂肪酸的不饱和程度。 H2C-O-C 硬脂酸三甘酯 HC (mp72℃ H2C-0-CMMMMMMMY H2C-O-C O 油酸三甘酯 Hc-O-C (mp.-4℃) H2c-O

z 熔点的高低主要决定于脂肪酸的不饱和程度。 一、甘油酯 Glycerides 3. Properties H2C HC H2C O C O C O C O O O H2C HC H2C O C O C O C O O O 硬脂酸三甘酯 (mp.72℃) 油酸三甘酯 （mp.-4℃）

3. Properties ●甘油酯的变质一一酸败( rancidity) 不饱和脂肪酸的氧化所导致。 initiation RCH=CH--CH-CH=-+ X. RCH= CHeCH—CH=CH—+HX H resonance contributor with isolated double bonds RCH-CH=CH-CHCH resonance contributor with conjugated double bonds 算- propagation RCH--CH=CH—CH=CH O-0 radical RCH=CH—CH2-CH=CH propagation RCH=CHCH—CH=CH—+ RCH-c=CH—CH=CH一 an alkyl hydroperoxide

3. Properties z 甘油酯的变质 —— 酸败 (rancidity) —— 不饱和脂肪酸的氧化所导致