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Chuang 5 HIDROCACBOiSr ^O & The ndo la ankan, xicloankan ? ChUng co diem gi gid'ng nhau vd khdc nhau vi cd'u tao vd tinh chdt ? & Cdc ankan dugc iing dung trong nhiing linh vuc ndo ? C Cdc nguon hidrocacbon no trong tu nhien. Nha may Igc hoa dau Ek- 109 Hidrocacbon no la hidrocacbon ma trong phan td chi co lien ket dan. l-lidrocacbon no dugc chia thanh hai loai: -Ankan (hay parafin) la nhCmg hidrocacbon no khong co mach vong. - Xicloankan la nhCrng hidrocacbon no co mach vdng. Hidrocacbon no la nguon nhien lieu chinh va la nguonMguyen lieu quan trong trong nganh cong nghiep hoa hoc. Bdi W ANKAN 25 r & Biei viei cdng thuc ca'u tao va gpi ten mdt sd ankan don gian. 'ZD Biei tinh chai hoa hpe dac trung cua ankan la phan ung the. & Biei duac t i m quan trpng cua hidrocacbon no trong cdng nghiep va trong ddi sdng. I - DONG DANG, DONG PHAN, DANH PHAP 1. Day dong ddng ankan Metan (CH^) va cac chat tiep theo cd cong thdc phan tu 0)^^, C^^, C4H1Q, C<5H[2,..., lap thanh day ddng ding ankan (hay parafin) ed cdng thuc chung C„H2„,2("^1)Trong phan td ankan chi cd cac lien ket don C - C, C - H. Mdi nguyen tu cacbon tao dugc 4 lien ket don hudng td nguyen tu C (nam d tam cua hinh tu dien) ve 4 dinh cua mgt td dien vdi gde lien ket CCC . HCH ^ CCH khoang 109,5°. Do dd. cac nguyen td cacbon trong phan tu ankan (trd C-^^ khdng cung nam tren mgt dudng thing. a) b) Hinh 5.1. Md hinh phdn tu butan (aj vd isobutan (b) 110 2. Oong phan Td C4H]Q trd di, dng vdi mdi cdng thde phan tu ed cac cdng thdc cau tao mach cacbon khdng phan nhanh va maeh cacbon phan nhanh cua cac ddng phdn mach cacbon. Thi du, dng vdi cong thdc phan tu CgHp cd eae chai ddng phan ca'u tao sau : CH, I - CH3 - CH, - CH, - CH2 - CH3 ; CH3 - CH - CH, - CH3 ; CH3 - C - CH3. CH3 CH3 3. Danh phap Mdt sd ankan maeh cacbon khdng phan nhanh duge gidi thieu trong bang 5.1. Bang 5.1. Ten vd mgt vdi hdng so vdt li ciia mdt so ankan mach khdng nhdnh vd ten gd'c ankyl tuang Ung Cong thurc cau t a ? thu gpn • j l ^ l ^ "Te^T™1?P Khoi lupng rieng, g/cm' thiirc Goc anky|(i) Ten goc phan tur CH, CH4 metan -183 -162 0,145 (-164°C) CH3- metyl CH3 - C H 3 CjHg etan -183 -89 0,561 {-lOQOG) CH3--CH2- etyl CH3 -CH2-CH3 C3H8 propan -188 -42 0,585 (- 450C) CHj--Cn2—CH2— propyl CH3--[CH2J2~CH3 C4H10 butan -138 -0,5 0,600 (0°C) CH3 -[Cn2]2—CH2— butyl CH3-- [ C H J j - -CH3 C5H12 pentan -130 36 0,626 (20°C) CH3--[CH2]3-CH2^ pentyl CHj-[CHj],- -CH3 ^6^14 hexan -95 69 0,660 (20°C) CH3--[CH2]4-CH2- hexyl CHj-^CH2]5--CH3 C7H16 Ineptan -91 98 0,684 (20°C) CH3--[CH2J5-CH2- heptyl octan -57 126 0,703 (20°C) CH3--[CH2]5-CH2- octyl CH3--[CHJe--CH3 CH3--[CH2],--CH3 C9H20 nonan -54 151 0,718 (20°C) CH3--[CH2J7-CH2- nonyl CH3--[CHJg--CH3 ^10^22 decan -30 174 0,730 (20OC) CH3--[CH2]8-CH2- decyl ' Khi lay mdt nguyen tir H khoi phan tir ankan, ta dirge gdc ankyl. Ill Cac ankan cd maeh nhanh dugc ggi ten theo danh phap thay the nhu sau : - Chgn mach cacbon dai nhai va ed nhieu nhanh nhai lam mach ehinh. - Danh sd thd tir cac nguyen tu cacbon mach ehinh td phia gan nhanh hon. - Ggi ten mach nhanh (nhdm ankyl) theo thd tu van chu cai eung vdi sd chi vi tri eua nd, tiep theo la ten ankan tuong ung vdi mach ehinh (xem bang 5.1). Thi du : CHo 1 2 3 4 C H , - CH - C H , - CHo CH3 1 21 3 CH3 - C - CHo CH3 2-metylbutan (isopentan) 2,2-dimetylpropan (neopentan) Mgt sd chai ed ten thdng thudng, thi du : isopentan, neopentan,... Bdc ciia nguyen tit C trong phan tu hidrocacbon no dugc tinh bing sd lien kei cua nd vdi cac nguyen tu cacbon khae. Tiii du : Trong phan tu 2-metylbutan, bae cua cac nguyen tu C sd 1 va sd 4 la I ; bae eua nguyen tu C sd 3 la II; bae eua nguyen tu C sd 2 la III. Trong phan td 2,2-dimetylpropan, bae cua nguyen tu C sd 2 la IV. II - TiNH CHAT VAT Li 6 dieu kien thudng, bd'n ankan dau day ddng ding (td CH4 de'n C4H[Q) la nhung chdt khi, eae ankan tie'p theo la chdt long, td khoang CjgHjg trd di la nhung chdt rdn. Ndi chung, nhiet do nong chdy, nhiet do soi va khdi luang rieng cua eae ankan tang theo chieu tang cua phan tu khdi (bang 5.1). Tai ca cac ankan deu nhe hon nudc va hau nhu khdng tan trong nudc, nhung tan nhieu trong dung mdi hiru co. Ill - TiNH CHAT HOA HOC O nhiet do thudng, cac ankan khdng tac dung vdi dung dich axit, dung dich kiem va cac chai oxi hoa nhu dung dich KMn04 (thude tfm)... Khi chie'u sang hoac dun ndng, eae ankan dd dang tham gia cac phan dng the', phan dng tach hidro va phan dng chay. 112 1. Phan ung the boi halogen Clo cd the thay the lan lugt tdng nguyen tu H trong phan tu metan : CH4 +CI2 - ^ ^ CH3CI + HCl CH3CI + CI2 - ^ ^ CH2CI2 + diclometan (metylen clorua) HCl CH2CI2+CI2 - ^ ^ CHCI3 triclometan (clorofom) + HCl CHCI3 + CI2 - ^ ^ CCI4 tetraclometan (cacbon tetraclorua) + HCl clometan (metyl cloma) Cac ddng ding eua metan cung tham gia phan dng the tuong tu metan. Thidu : CH3CH2CH2CI + HCl CH3CH2CH3 + CI2 ^ f r \ i-^'°p>-«p^"<43%) C H o - C H - C H o + HCl i I Cl 2-clopropan (57%-) Nhdn xet: Nguyen tu hidro lien kei vdi nguyen tu cacbon bae cao hon de bi the hon nguyen tu hidro lien ket vdi nguyen tu cacbon bae thip hon. Cae phan dng tren dugc ggi la phan irng halogen hod. Cac sin phim the duge ggi la ddn xudt halogen ciia hidrocacbon. 2. Phan ung tach Dudi tac dung cua nhiet va chit xtic tac thieh hgp, cae ankan cd phan td khdi nhd bi tach hidro thanh hidrocacbon khdng no tuong ung : Thi du : CH3 - CH3 500 ° r xt ' ) CH2 = CHo + H2 6 nhiet do eao va ed mat chit xuc tac thieh hgp, ngoai viec bi tach hidro, cac ankan cdn cd the bi phan cit mach cacbon tao thanh cae phan tu nhd hon. 8-HH11(C)-A 113 Thidu : CH4 + C3H6 CH3 — CH2 "" CH2 ~ CH; t", Xt C2H4 -I- C2Hg ^ 4 ^ 8 + H2 3. Phan ung oxi hoa Khi bi ddi, cac ankan deu chay, toi nhieu nhiet : 3n + l CnH2n.2 + O2 > nC02-H(n+l)H20 Ne'u thie'u oxi, phan dng chay eua ankan xay ra khdng hoan toan : sin phim chay ngoai COj, H2O cdn cd C, CO,... I V - D I E U CHE 1. Trong phdng thi nghiem Metan duge dieu che' bing each dun ndng natri axetat khan vdi hdn hgp vdi tdi xut (hinh 5.2) : CH3C00Na + NaOH ^''°''° ) CH4t + Na2C03 H6n hgp CHgCOONa, CaO, NaOH 2. Trong cong nghiep Cac ankan la thanh phin chinh cua diu md, khf thien nhien va khf md diu. Td diu md. bing phuang phap chung cit phan doan, ta thu dugc eae ankan d cac phan doan khae nhau. Td khf thien nhien va khi mo dau cung thu dugc cac ankan CH4, CjH^, CjHg, C4H,Q, ... 114 8 - HH11(C)-B V - ONG DUNG CUA ANKAN Cac ankan cd dng dung trong nhieu linh vuc khae nhau : lam nhien lieu, nguyen lieu cho eong nghiep. Chat dot Chat boi tran BAI TAP 1. The nao la hidrocacbon no, ankan, xicloankan ? 2. Viei cdng thdc phan td cua cac hidrocacbon tuong dng vdi cac gdc ankyl sau -CH3, -C3H7 , -CgH^g. 3. Viei phuong trinh hoa hpe cija cac phan ifng sau : a) Propan tac dung vdi clo (theo ti le moi 1:1) khi chieu sang. b) Tach mpt phan td hidro tU phan td propan. c) Ddt chay hexan. 115 Cac hidrocacbon no dupc dung lam nhien lieu la do nguyen nhan nao sau day ? A. Hidrocacbon no cd phan dng the. B. Hidrocacbon no cd nhieu trong tii nhien. C. Hidrocacbon no la chat nhe hon nudc. D. Hidrocacbon no chay toa nhieu nhiet va cd nhieu trong tU nhien. Hay giai thich : a) Tai sao khdng dupc de cac binh chda xang, dau (gom cac ankan) gan Ida, trong khi dd ngudi ta cd the nau chay nhUa dudng (trong thanh phan cung cd cac ankan) de lam dudng giao thdng. b) Khdng dung nUdc de dap cac dam chay xang, dau ma phai dung cat hoac binh chda khf cacbonic. Cdng thdc ca'u tao CH3-CH - C H 2 -CH2 -CH3 dng vdi ten gpi nao sau day ? CH3 A. neopentan B. 2-metylpentan C. isobutan D. 1,1-dimetylbutan Khi ddt chay hoan toan 3,60g ankan X thu dupc 5,60 lit khi C O j (dktc). Cdng thUc phan tdcija X la A. C3H8 B. C5H10 C. CjH^j D. C4H10 116 XICLOANKAN £7 Biei the nao la xicloankan va mdt vai dac diem vd cau tao phan tu. £7 Biei duac su gid'ng va khae nhau vd tinh chai cua xicloankan so vdi ankan. I - CAU TAO Xicloankan la nhiing hidrocacbon no cd mach vong (mgt hoae nhieu vdng). Chung ta chi xet cac xicloankan cd mgt vdng (xicloankan don vdng hay cdn ggi la monoxicloankan). Mgt sd xicloankan don gian ed cdng thdc ciu tao va ten ggi dudi day (bing 5.2). Bang 5.2. Ten thay the'vd mat vdi hdng so vdt li cua mdt sd xicloankan don gidn Cdng thdc cau tao C6ng thii'c phan t d T§n thay the" t °C 'itc CHp / \ HpC — CHo hay A C3H5 xiclopropan HgC - CH2 ' 1 HpC - CHp hay n C4H8 hay 0 CHo HpC CHo ^ \ / ^ H2C — CHrt t^oC ^ -127 -33 xiclobutan -90 13 C5H10 xiclopentan -94 49 C5H12 xiclohexan 7 81 CnH2n. n > 3 xicloankan f HoC — CHo , HpC^ 'z i ^ ^CHp ^ hay HpC — CHp 0 "^ Cdng thdc va ten chung 117 Cdng thdc phan tu chung cua cac xicloankan don vdng la C^H^^ vdi n > 3. Ten cua cac xicloankan don vdng khong nhanh dugc ggi bing each ghep td xicio vao ten cua ankan maeh khong nhanh cd eung sd nguyen tu cacbon. Trong phan tu xicloankan, cac nguyen tu cacbon lien ket vdi nhau bang lien ket CT tao ra mach vdng. Nguyen td cacbon cua vdng lien ket vdi cac nguyen tu hidro hoac gdc ankyl. Thi du HoC — CHo 7 \ H2C CH2 HgC CH-CH3 hay { ^ CH3 metylxiclohexan II - TINH CHAT HOA HOC Xiclopropan va xiclobutan, ngoai khi nang tham gia phan dng the tuong tU ankan, cdn dd tham gia phdn dng cgng md vdng. Xicloankan cd vdng ldn hon (nam hoac sau canh,...) ed tfnh chit tuong tu ankan : tham gia phin ung the, phin ung tach. 1. Phan ling the Tuong tu ankan, nguyen tu hidro trong phan tu xicloankan cd the bi the' bdi nguyen tu halogen khi chieu sang hoac dun ndng. + Br2 xiclopentan 2. t° > r \ >-Br / + HBr bromxiclopentan Phan ung cong m d vdng a) Xiclopropan, xiclobutan va xicloankan vdng 3 hoac 4 canh cd phan dng cdng vdi hidro (dun ndng ed niken lam xue tac) gid'ng anken. Phan dng lam gay mdt trong cac lien ket C - C eua vdng va hai nguyen tu hidro cgng vao hai dau cua lien kei vda bi gay tao thanh ankan tuong dng. 118