第五章不飽和脂肪烴第四章要點(diǎn)復(fù)習(xí)1、烷烴的沸點(diǎn)變化規(guī)律3、環(huán)丙烷的開環(huán)反應(yīng)開環(huán)原則：斷裂連接取代基最多和最少的鍵，H加在含H多的C上。2、不同H的活潑性和不同X的選擇性本課要點(diǎn)1、烯烴的催化加氫2、烯烴的親電加成反應(yīng)3、烯烴的自由基加成C＝C烯烴共軛二烯烴炔烴C＝C—C≡C—C＝C－C＝C官能團(tuán)H§5.1烯烴官能團(tuán)分析CR取代電負(fù)性sp2＞sp3

-H加成、氧化電子云密度高、易極化

鍵反應(yīng)類型原因反應(yīng)位置①

鍵②-H+

-

一、烯烴的物理性質(zhì)——自學(xué)二、烯烴的化學(xué)性質(zhì)（一）催化加氫C＝C+H2催化劑－C－C－HH1、反應(yīng)機(jī)理：H—HC＝C①H2吸附到催化劑表面②烯烴吸附到催化劑表面③生成中間配合物④加H后離開催化劑表面Pt或Ni2、氫化熱順式加成氫化熱越小，體系越穩(wěn)定。①反式比順式穩(wěn)定。——1mol烯烴加氫放出的能量。H3C–C＝C–CH3CH3CH3②連接甲基越多，越穩(wěn)定。C＝CH3CCH3HHC＝CH3CCH3HH乙烯丙烯順-2-丁烯反-2-丁烯2,3-二甲基-2-丁烯氫化熱名稱112137126115120（二）親電加成+E+

Nu-C＝CECCNu(加成試劑)加成斷裂1個(gè)

鍵生成2個(gè)

鍵HX、H2SO4、H2O、X2、HOX親電加成反應(yīng)歷程：①分步進(jìn)行；②E+先進(jìn)攻正碳離子中間體環(huán)正離子中間體親電部分親核部分C＝C1、加H-XC＝C[]H+CCH+H-XH++X-CCHXH+慢快X-正碳離子越穩(wěn)定，反應(yīng)越容易發(fā)生。CH3–CH=CH2+H-XHCH3–CH–CH2XCH3–CH–CH2XH2-鹵丙烷1-鹵丙烷馬氏規(guī)則：不對(duì)稱烯烴和極性試劑加成，試劑中帶正電部分(H+)加在含氫較多的C上。√HI＞HBr＞HClCH3–CH=CH2+H+如何解釋馬氏規(guī)則HCH3–CH–CH2XCH3–CH–CH2XH√HCH3–CH–CH2CH3–CH–CH2H++從反應(yīng)活潑中間體(正碳離子)穩(wěn)定性解釋20正碳離子10正碳離子∧2、加H-OSO3H(硫酸氫乙酯)——間接水合制醇CH3CH2-OHH2OCH2=CH2CH3CH2-OSO3HH2SO4CH3–CH=CH2CH3–CH–CH3OSO3HH2SO4CH3–C=CH2CH3CH3–C–CH3OSO3HCH3H2SO4H2OCH3–CH–CH3OHH2OCH3–C–CH3OHCH3(乙醇)3、加H2O63%80%98%——直接水合制醇？CH2=CH2+H2OCH3CH2-OHH3PO4300℃，7-8MPa(乙醇)(異丙醇)(叔丁醇)(硫酸氫異丙酯)(硫酸氫叔丁酯)4、異構(gòu)化加成產(chǎn)物CH3C—CH–CH3CH3CH3Cl+CH3CH–CH–CH3CH3Cl+CH3C—CH–CH3CH3CH3+CH3C—CH–CH3CH3+H1,2-負(fù)氫遷移1,2-甲基遷移HCH3C—CH–CH3CH3+CH3C—CH–CH3CH3CH3+60%40%83%17%——正碳離子的重排CH3C—CH=CH2CH3CH3HClCH3C—CH–CH3CH3ClCH3CH3CH–CH=CH2CH3HClCH3C–CH2–CH3CH3Cl20正碳離子30正碳離子20正碳離子30正碳離子1223要點(diǎn)？只有當(dāng)正電荷與相鄰位置的H或者是烷基交換位置后，能生成更穩(wěn)定的正碳離子時(shí)，重排才會(huì)發(fā)生。CH3C–CH2–CH–CH3CH3+HHCH3C–CH2–CH–CH3CH3+？CH3C–CH2–CH–CH3CH3+CH3CH3C–CH2–CH–CH3CH3+？CH3練習(xí)1：寫出下列反應(yīng)的機(jī)理

過(guò)渡狀態(tài)——配合物溴鎓正離子＝CC+Br—Br—CC+-+–Br‥—CCBr+產(chǎn)物有立體選擇性＝CCBr—BrBr+反式加成5、加X(jué)2反應(yīng)能力：F2＞Cl2＞Br2＞I2溴水褪色，用于鑒別。Br-Br-CCBrBrCCBrBr+HHCH3CH3Br+BrHCH3BrHCH3HCH3BrBrBr-BrBrCH3HCH3HBrBrCH3HCH3H2R,3R2S,3SBrBrCH3HCH3Hcab2R,3ScabcbacbaBrHCH3BrHCH3BrBrHCH3(Z)-2-丁烯加溴生成等量的(2R,3R)和(2S,3S)的事實(shí)，是對(duì)反式加成機(jī)理最有力的支持。若是順式加成6、加次鹵酸HOXCH3–C=CH2CH3+HO－BrCCXX有沒(méi)有？CCOHXC＝CX2CCX+OH-CCOHXC＝CHO－XX2+H2OCH3–C–CH2–BrOHCH3CH3–C–CH2–OHBrCH3誰(shuí)為主？-+√√試劑中帶正電部分加在含氫較多的C上。

H＝(

)－(C-Cl)＝264－341＝-77放熱

H＝(H-Cl)－(C-H)＝431－395＝36

吸熱（三）自由基加成——過(guò)氧化物效應(yīng)CH3–CH=CH2+HBrCH3–CHBr–CH3CH3–CH2–CH2BrR2O2/hv——反馬加成鏈引發(fā)：R2O22RO?RO?+HBrROH+Br?鏈增長(zhǎng)：CH3–CH=CH2+Br?CH3–CH–CH2Br?CH3–CH–CH2Br+HBr?CH3–CH2–CH2Br+Br?CH3–CHBr–CH2?△H=(H-Br)－(C-H)=366－395=-29△H=()－(C-Br)=264－288=-16放熱放熱

H＝(

)－(C-I)＝264－224＝40吸熱

H＝(H-I)－(C-H)＝297－395＝-98放熱唯一297H-I224C-I366H-Br288C-Br431H-Cl341C-Cl395C-H264

離解能(kJ·mol-1)+BH3（四）硼氫化—氧化反應(yīng)CH3CH=CH2CH3CH2CH2–BH2甲硼烷丙基甲硼烷(CH3CH2CH2)2–BH(CH3CH2CH2)3–BCH3CH=CH2CH3CH=CH21、硼氫化試劑2、硼氫化歷程——反馬產(chǎn)物、順式加成、沒(méi)有重排CH3–CH＝CH2-+H—B四中心過(guò)渡態(tài)CH3–CH—CH2HBCH3–CH—CH2HB混合物+B2H6乙硼烷THF四氫呋喃反馬產(chǎn)物電負(fù)性H(2.1)>B(2.0)3、硼氫化—氧化的應(yīng)用(CH3CH2CH2)3BOH-H2O23CH3CH2CH2OH+H3BO3制備伯醇、沒(méi)有重排產(chǎn)物②OH-H2O2①B2H6CH3C–CH2CH2OHCH3CH3CH3C–CH=CH2CH3CH3例：CH3C—CCH3CH3CH3OHH-OHCH3C–CH=CH2CH3CH3H+CH3C—CH–CH3CH3CH3+CH3C—CH–CH3CH3CH3+1,2-甲基遷移+CH3C－CHCH3CH3OH