Thiết kế bài giảng hóa học 12 nâng cao (tập 1) phần 2

ChiFcng 3. AMIN, AMINO AXIT, PROTEIN
Baill.AMIN
A. MUC TIEU BAI HOC
LKilnthiFC
HSbiit:
•

Dinh nghia, cong thiic chung, dac diem cau tao, danh phap cua cac amin
dien hinh.

•

Tinh chat vat li: Quy luat bien doi dp tan, nhiet dp soi cua cac amin.

•

Tinh chat boa hpc: Tinh bazo cua amin, phan ling the o nhan benzen ciia
anilin.

HShiiu:
•

cau tao phan tir, tinh chat, ling dung va dieu che amin.

•

Nguyen nhan gay ra tinh bazo cho cac amin, tai sao anilin khong lam quy,
phenolphtalein doi mau?

2. KT nang
•

Nhan dang cac hgp chat amin.

•

Viet chinh xac cac phuong trinh boa hpc.

•

Quan sat, phan tich cac thi nghiem chung minh cua amin.

•

So sanh luc bazo giiia cac amin voi nhau va voi NH3.

3. Tinh cam, thai do
Hiiu dugc each giai quyet mau thuan giiia cau tao va tinh chit boa hpc
ciia amin tao nen sir himg thii khi giai quyet van dl moi.
Thiy dugc tam quan trgng cac amin trong doi sing va san xuit gay hiing
thu cho HS khi hgc bai nay.

159


B. C H U A N B! C U A GV VA HS
•

GV:

- May tinh, may chilu, cac philu hgc tap.

- Hoa chit: NH3, anilin, metyl armn, nuoc cit, quy tun, nuoc brom.
- Dung cu: Ong nghiem, cap Ing nghiem, bg gia thi nghiem.

•

HS: Xem truoc bai amin.

C. TI^N TRiNH DAY - HOC
Hogt dgng cUa GV

Hogt dgng cUa HS

I. KHAI NIEM, PHAN LOAI, DANH PHAP VA DONG PHAN
Hogt dgng 1

I.KHAINIEM
GV chieu len man hinh cac cong thiic

HS quan sat, thao luan:

NH3, CH3NH2, CH3-NH-CH3, (CH3)3N

- So sanh

Yeu cau HS: So sanh cau tao cua NH3 + Giong nhau: deu co N"'' (boa tri III).
voi cac chat con lai. Biet cac chat do la + Khac nhau: NH3 c6 hidro lien ket voi
amin tir d6 neu khai niem amin?
N, cac chat khac co goc hidrocacbon
lien ket voi N ciia NH3.
- Khai niem: Khi thay the mot hay

nhieu nguyen tic H trong phan tir NH}
bdng mot hay nhieu goc hidrocacbon ta
GV yeu cau HS: Lap day dong dang
cua amin no don chiic, mach ho.

dugc amin.
HS thao luan:
Tir cong thiic amin don gian nhat CH5N
-> dong dang co dang CH5(CH2)kN ->
Ck+iH2k+5N
Dat k+1 = n -> CnH2n+3N (n> 1)

GV: Tuong tu viet cong thirc tong quat
ciia cac amin la dong dang cua C6H7N.

160

HS: Cong thiic la CnH2n-5N (n>6)


Hogt dgng cUa GV

Hogt dgng cua HS
Hogt dgng 2

2. PHAN LOAI
GV cho HS nghien ciiu SGK va dat vin HS thao luan va nhan xet amin phan
de tra loi cac cau hoi.
lam 2 loai thong dung la:
- Co the chia amin thanh nhiing loai a) Theo dac diem cau tao goc hidrocacbon

+ Amin beo: CH3NH2, C2H5NH2...
nao? - Cho vi du minh hga.
+ Amin thom: C6H5NH2, CH3C6H4NH2
- Neu khai niem bac amin.
+ Amin di vong : pirolidin
- Phan biet bac amin voi bac ancol.
b) Theo bac amin
+ Amin bac mot: CH3NH2, C6H5NH2
+ Amin bac hai: CH3-NH-CH3,
CH3NHC6H5
+ Amin bac ba: (CH3)3N
- Bac amin la so nguyen tir H trong
phan tir NH3 bi thay the.
- Phan biet bac amin voi bac ancol:
+ Bac ancol la bac cua C lien ket voi
nhom OH.
+ Bac amin la so nguyen tir H cua NH3
bi thay the.
Hogt dgng 3
3. DANH P H A P
GV chilu len bang 3.1 (SGK) len man HS quan sat ,thao luan dua ra nhan xet
Co 2 each gpi ten.
hinh cho HS quan sat va yeu cau:
+ Ten goc-chiic: co cau tnic
- Co bao nhieu each ggi ten?
Ten amin = Ank + yl + amin
- Neu quy tac ggi ten amin?
+ Ten thay the: c6 cau tnic
- Gpi ten cac amin sau day?
Ten amin = Ankan + vi tri + amin

CH3-CH(CH3)-CH2-NH2
+ Ten thong thuong chi ap dung cho
(CH3)3C-NH2
mot so amin.
CH3-NH-C2H5
Vi du: C6H5NH2 anilin
0-CH3-C6H5NH2

161


Hogt dgng cUa GV

Hogt dgng cUa HS

GV bo sung: Neu co nhilu nhom chiic
amin thi them cac tilp diu ngir di, tri...
Vidu:
NH2-(CH2)6-NH2 hexametylendiamin
GV chieu len man hinh bai tap len man HS thao luan:
hinh cho HS thao luan
Viet cong thirc cac amin co ten sau day:
dimetylamin, phenylamin, benzylamin,
Dimetylamin: CH3-NH-CH3
hexan-1,6-diamin,
Phenylamin: C6H5NH2
o-metylpheylamin, etylmetylamin.
Benzylamin: C6H5CH2NH2
Hexan-1,6-diamin: NH2(CH2)6NH2
o-metylpheylamin

NH2

Etylmetylamin: C2H5-NH-CH3
Hogt dgng 4
4. DONG P H A N
GV yeu cau HS: Viet dong phan va gpi HS thao luan:
ten cac chat co cong thiic phan tir CH3-CH2-OH
ancol etylic
C2H6O.
dimetyl ete
CH3OCH3
GV gioi thieu: Tuong tu C2H6O thi HS thao luan: C4H11N la amin no, mach
amin cung co cac dong phan vi tri ho, don chirc.
nhomN.
CH3-CH2-CH2-CH2-NH2
(1)
Yeu cau HS:
CH3-CH2-NH-CH2-CH3
(2)
- Viet ten cac amin co cong thiic CH3-CH2-CH2-NH-CH3
C4H11N.
CH3-CH(CH3)-CH2-NH2
- Phan loai cac amin theo bac.
CH3-CH(CH3)-NH-CH3
CH3-CH2-N(CH3)2

162

(3)

(4)
(5)
(6)


Hogt dgng cua GV

Hogt dgng cua HS

(7)
GV chieu len man binh bai tap sau: Sl (CH3)3C-NH2
amin thom co cong thiic phan tir C7H9N CH3-CH2-CH(CH3)-NH2
(8)
la
(1), (4). (7), (8) la amin bac I
(2), (3), (5)
la amin bac II
B. 5
A. 4
C. 6
D. 3
(6)
la amin bac III
HS thao luan cho ket qua:
NH2

NH2

NH2

CH3
NH-CH3

CH2-NH2

Co 5 dong phan chpn dap an B

Hogt dgng 5
II. TINH C H A T V A T Li
GV cho HS nghien ciiu SGK va yeu
cau HS nhan xet ve:

HS: Nghien ciiu SGK va nhan xet
- Trang thai:

- Trang thai (o nhiet dp thuong).

Metylamin, dimetylamin,
etylamin
trimetylamin,
la
chat
khi
c6
mau
khai
- Sir bien thien ve dp tan.
kho chiu. cac amin khac la chat long
- Trang thai, mau sac, kha nang boa tan
hoac ran.

ciia anilin.
- Giai thich tai sao anilin de lau ngay - La cac hgp chat khong mau, 4 amin
dau deu tan tot trong nuoc, thir tu cac
trong khong khi thi co mau den.
amin c6 do tan giam theo chieu tang
phan tir khoi.
- Anilin la chat long khong mau soi o
184 C, it tan trong nuoc, tan nhilu
trong dung moi hiru co.
- De lau anilin ngoai khong khi thi co
mau den do anilin bi oxi khong khi oxi
boa.

163


Hogt dgng cua GV

Hogt dgng cua HS

GV nhan xet va bo sung: tit ca cac HS quan sat
amin deu dgc nhu nicotin, anilin...
GV chieu bang sau len man binh
Chit

C2H50H

C2H5NH2

C3H8

t"

78,3°C

16,6°C

-42°C

I s

va dat van de: Tai sao amin va ancol co
phan tir khoi xap xi nhau ma nhiet do
soi chenh lech nhau rat Ion.
GV huong dan HS giai quyet van de

HS thao luan va nhan xet.

- So sanh thanh phan cau tao ciia 3 chat - Deu CO phan tii khoi xap xi nhau.
tren.
- Khac nhau la do:
- Yeu to nao anh huong den nhiet do C3H8 gom CO C,H khong co nhom chiic
soi.
C2H5OH CO nhom chiic hidroxyl.
- Tai sao ancol co nhiet do soi cao C2H5NH2 CO nhom chiic amin.

nhat.

- Nhom chiic anh huong toi nhiet do
soi.

- Ancol CO nhom OH phan cue nen co
lien ket hidro.

Vay amin co lien ket hidro hay khong? HS: Theo khai niem vl lien kit hidro
Neu CO hay so sanh lien ket hidro cua thi amin co lien ket hidro.
ancol va amin.
Lien kit N-H.kem phan cue ban lien
kit 0 - H nen lien kit hidro cua amin
yeu hon lien ket hidro ciia ancol.
GV yeu cau HS ket luan van de.

HS ket luan van de:
Amin co lien ket hidro rit ylu nen co
nhiet do soi thap hon ancol va cao hon
ankan.

164


Hogt dgng cua GV

Hogt dgng cua HS

Hogt dgng 6
III. CAU TAO PHAN Tiy VA TINH C H A T H O A HOC
Cach 1:
GV yeu cau HS len bang viet cong thiic HS len bang viet cong thiic cau tao
cau tao va neu dac diem cau tnic cua NH3.
phan tir NH3.
N

H H
H
NH3 CO cau tao dang hinh thap 1 dinh la
N va 3 dinh con lai la H, tren nguyen tir
N con CO 1 cap electron tu do (chua lien
kit).
GV gioi thieu cho HS biet: Amin co HS len bang viet cong thiic cau tao
cau tao giong voi NH3. Yeu cau mot
N
N
HS len bang viet cau tao ciia
metylamin, dimetylamin, trimetylamin,
CH3 CH, H
CH3 H
H
anilin.
dimetylamin
metylamin
N
CH3 CH3 CH3

N
n p^
H

trimetylamin
GV yeu cau HS du doan tinh chat boa
H S thao luan v a nhan xet:
hoc cua amin.

C6H<;
<^6r>5

anilin

Amin co cau tao tuong tu amoniac
- Tinh bazo.
- Tinh khir.
- Tinh chat cua goc hidrocacbon.
Cach 2:

HS quan sat (nghien cim SGK)

GV chilu hinh 3.2 SGK len man hinh - cau tao ciia amin tuong tu NH3.
165


Hogt dgng cUa GV

Hogt dgng cUa HS

(hoac cho HS nghien ciiu SGK) yeu - Tinh chit cua amin tuong tu NH3.
cau HS nhan xet vl:
+ Tinh bazo.
- Cau tao ciia NH3 va cac amin.
+ Tinh chit cua glc hidrocacbon.
- Du doan tinh chat hoa hoc ciia amin.
+ Tinh khir.
Hogt dgng, 7
1. TINH C H A T C U A CHLTC AMIN

a) Tinh baza
GV lam thi nghiem. Nhiing giay quy HS quan sat
vao cac dung dich sau: metylamin, - Hien tugng:
amoniac, anilin. Yeu cau HS quan sat,
+ Ong dung dung dich metyl amin,
neu hien tugng va giai thich.
amoniac quy tim chuyen thanh mau
xanh.
+ Ong dung anilin quy tim khong doi
mau.
GV dieu khien, huong dan HS giai - Giai thich:
thich.
Metyl amin va nhieu amin khac khi tan
vao nuoc phan ung voi nuoc tuong tu
NH3 sinh ra ion 0H~.
NH3 + H2O ^ ^ [ N H 4 r + 0 H '
CH3NH2 + H2O "^^ [CH3NH3]^ + OH"
Vi vay CH3NH2, NH3 lam quy tim hoa
xanh.
GV bo sung: Anilin va cac amin thom HS ghi bai.
phan img rat kem voi nuoc va tinh bazo
ciia anilin rat yeu (yeu hon CH3NH2,
NH3) nen khong lam quy tim doi mau
phenolptalein
HS quan sat va nhan xet:
GV tiep tuc lam thi nghiem:

166

Hogt dgng cua GV

Hogt dgng cua HS

Nho vai gigt dung dich vao 2 Ing - Ong 1 thay anilin hau nhu khong tan.
nghiem. Ong nghiem 1: dung nuoc cit lang xuong day ong nghiem.
ong nghiem 2: dung dung dich HCL - Ong 2 thay anilin tan.
Yeu cau HS: - Quan sat.
Giai thich:
- Neu hien tugng.
+ Anilin hau nhu khong tac dung vai
- Giai thich.
nuoc nen anilin hau nhu khong tan, no
tao van due roi lang xuong day
+ Anilin tan dugc trong HCl do co phan
img tao ra hgp chat tan trong nuoc
C6H5NH2 + HCl ^[C6H5NH3]^Cr
Phenylamoni clorua
GV dat van de: Tai sao amin beo (ankyl HS thao luan giai quyet van de duoi su
amin) lai co tinh bazo manh hon anilin? dieu khien cua GV
GV dieu khien huong dan HS giai - cau tao cua NH3
quyet van de.
- cau tao ciia NH3 giai thich tai sao lai
CO tinh bazo ?

\../

/ / \
H H
H

NH3 con CO mot cap electron tu do nen
CO kha nang nhan proton (H"^)^' co tinh
bazo.
- So sanh NH3 va CH3NH2

0
N
/ / \
H
H H

Q
N
/ /
CH, H

\
H

Do goc ankyl(CH3) c6 hieu img diy
electron len N lam cho mat do electron
tu do tren nguyen tir N tang -^ de cho
cap electron tu do nay (de cong H"^) ban
nen c6 tinh bazo manh hon NH3.

167


Hogt dgng cUa GV

Hogt dgng cua HS

- So sanh cap electron tu do trong NH3 - Tuong tu v6i NH3 va C6H5NH2 thi
va trong ankyl amin (nhu metyl amin).
nhom CeHs co bieu ling but electron
- So sanh cap electron tir do trong NH3 ciia nhom NH2 lam giam mat do
electron ciia nguyen tir N so voi mat do
va trong anilin.
electron trong NH3.

0

Q
N

.N
H

GV yeu cau HS kit luan vin dl.

GV chieu bai tap sau len man hinh:

H

H

H
n H

CsH

605

-> lam giam kha nang nhan H^ -^ tinh
bazo cua anilin yeu hon cua NH3
HS ket luan: Tinh bazo cua anilin co
the manh hon hay yeu hon NH3 tuy
thuoc vao goc hidrocacbon lien ket voi
nito.
HS thao luan:

Day chat nao sau day dugc sip xIp Chpn dap an C.
theo thir tu luc bazo tang din
A. CH2=CH-NH2,
(CH3)2NH
B. NH3, CH3NH2,
(CH3)2NH
C. CH2=CH-NH2,
(CH3)2NH
D.
(CH3)2NH,
CH2=CH-NH2, NH3

CH3NH2, NH3,
CH2=CH-NH2,
NH3,

CH3NH2, HS thao luan viet phuang trinh hoa hpc
CH3NH2,

3CH3NH2 + 3H20 + FeCl3-»

3CH3NH3CI + Fe(0H)3i

Phuong trinh chay
GV: Tuong tu NH3 hay vilt phuong
trinh boa hgc ciia metylamin voi dung 2 C n H 2 n + 3 N + - ^ ' ^ 0 2 ^
dich FeCl3.
2
2nC02 + (2n+3)H20 + N2
168


Hogt dgng cUa GV

Hogt dgng cua HS

GV yeu cau HS: Viet phuong trinh hoa
hpc chay tong quat cua day ding ding
metylamin
b) Phan lirng vol axit nitro"
GV cho HS nghien ciiu SGK va yeu
cau HS neu hien tugng xay ra khi cho
etylamin tac dung voi axit nitro
(NaN02 + HCl) va viet phuang trinh
hoa hgc.

HS nghien ciiu SGK va nhan xet
- Hien tugng co khi N2 thoat ra.
- Phuong trinh h6a hpc
C2H5NH2 + HONO -^ C2H5OH + N2
+ H2O

GV yeu cau HS giai thich tai sao lai
cho etylamin tac dung voi hon hgp
NaN02 + HCl ma khong cho etylamin
tac dung true tiep vai HONO.

HS thao luan va giai thich
Axit HONO khong ben, de phan buy
nen khong co san HONO trong phong
thi nghiem vi vay phai dieu che tir hon
hgp NaN02 + HCl.

GV yeu cau HS nghien ciiu SGK va HS nghien ciiu SGK va nhan xet
cho biet:
- Phan img xay ra 6 nhiet dp rat thap tir
- Dieu kien phan ung ciia anilin va 0-5"C.
amin thom bac 1 voi HONO.
- Phuong trinh boa hpc
- Viet phuong trinh boa bpc.
C6H5NH2 + HONO + HCl
""^"^ >
- Ung dung ciia san pham phan img
C6H5N2 c r + 2H2O
nay.
Benzendiazoni clorua
- Hgp chat diazo c6 vai tro trong tong
hgp hiru co va dac biet la ting hgp
pham nbupm azo.
c) Phan ihig ankyl hoa
GV cho HS nghien ciiu SGK, yeu cau HS nghien ciiu SGK va nhan xet

HS vilt phuong trinh boa hpc cua ankyl - Phuang trinh boa hpc
halogenua voi amin bac 1 va nhan xet
C2H5NH2+CH3I-^ C2H5NHCH3 +HI
vl bac cua san pham.
169


Hogt dgng cua GV
GV bo sung:

Hogt dgng cUa HS
- san phim phan ling la amin bac II.

- Phan ling tren gpi la phan img ankyl HS ghi bai.
h6a.
- San pham ciia phan img con tiiy
thuoc vao ti le cua cac chat nen co the
thu dugc amin bac II hay amin bac III.
- Do sinh ra axit nen trong thuc te san
pham CO the la muoi ankyl amoni.
Hogt dgng 8
2. P H A N iTNG THE 6 N H A N THOM CUA ANILIN
GV lam thi nghiem:

HS quan sat

Cho vai gigt dung dich Br2 vao 2 ong - Hien tugng: Ong nghiem dung dung
nghiem: ong 1 la dung dich metyl amin. dich anilin xuat hien ket tiia trang.
ong 2 la dung dich anilin roi lac nhe. - Giai thich: Tuong tu voi phenol thi
Yeu cau HS:

nhom -NH2 day electron vao nhan
- Quan sat
thom lam giau electron tai cac vi tri
- Neu hien tugng
- Giai thich
- Viet phuang trinh h6a hgc

ortho-para nen de dang thay the nguyen
tir hidro bang nguyen tir brom tao ra
2,4,6-tribrom anilin
- Phuong trinh boa hpc
NH2

NH2

(^.3B.^ ^'-0"'-3HBr
^ - ^

i ^ 4'(trang)
Br
GV bo sung: Phan img nay de nhan biet - Metyl amin khong co hien tugng tren.
anilin.
GV yeu cau HS: Chiing minh su anh HS thao luan.
huong qua lai giiia goc phenyl voi
nhom chirc amin.

170


Hogt dgng cua HS

Hogt dgng cUa GV

- Nhom NH2 day electron vao nhan
benzen lam tang mat do electron tren
nguyen tir C tai cac vi tri ortho-para -^
de tham gia phan ling the brom.
- Nhom CeHs hut electron ciia nb6m
NH2 lam cho cap electron tu do ciia N
bi giir chat hon -» lam giam tinh bazo.
IV. iTNG DUNG VA DIEU CHE
Hogt dgng 9
1. LTNG DUNG
GV cho HS nghien ciiu SGK va yeu HS nghien cim SGK va nhan xet.
cau HS cho biet ling dung cua cac - Amin dugc dimg trong tong hgp hiiu
amin, cho vi du minh hpa:
CO. Dac biet la cac diamin diing de tong
hgp polime.
Vi du: Anilin la nguyen lieu trong cong
nghiep pham nbupm, polime, dugc

pham...
Hogt dgng 10
2. DIEU CHE
- Dieu che amin co nhieu each nhu:

HS hoan thanh cac so do.

+ Thay the nguyen tir H trong phan tir Phuang trinh boa hgc
amoniac theo so do.

CH3I + NH3 -^ CH3NH2 + HI
NH3 - ^ ^

CH3NH2

(CH3)2NH - ^ ^

^_"f >

(CH3)3N

+ Khu hgp chit nitro

CH3I + CH3NH2 ^ (CH3)2NH + HI
CH3I + (CH3)2NH -^ (CH3)3N + HI
Phuong trinh h6a hpc
C6H5NO2 + 7HCldu +3Fe -^

C6H5NO2

"^"HFe^HCl) ^ C6H5NH3CI

C6H5NH3CI + 3FeCl2 + 2H2O

^NaOlL^CoHsNHz

171


Hogt dgng cUa GV

Hogt dgng cUa HS

GV yeu cau HS hoan thanh cac so dl (Hoac viet ggn
tren.
C6H5NO2 + 6[H] -^ C6H5NH2+ 2H2O)
C6H5NH3CI + NaOH -^ C6H5NH2
+ NaCl + H2O
Hogt dgng 11

CUNG CO BAI V A BAI TAP VE N H A
GV nhac lai cac noi dung da hgc. Yeu HS lang nghe va he thong kien thiic da
cau HS luu y cac diem chinh sau:
hoc.
- Khai niem amin.
- Bac amin (phan biet voi bac ancol).
- Danh phap amin.
- Tinh chat vat li.
- Tinh chat cua amin la tinh chat nhom
amin, phan ling the ciia cac anilin.
- Ung dung ciia amin.
GV Phat cac phieu hpc tap sau cho HS HS thao luan
cimg CO.
Phieu 1. Co bao nhieu dong phan la Dap an A
amin bac hai trong cong thiic C4H9N
A. 3

B.2

C. 1

D.4

Phieu 2. So amin thom co cong thiic Dap anC
phan tir la C7H9N la
A. 2

B. 4

C. 5

D. 7

Phieu 3. Sap xep cac amin sau theo luc Dap an B
bazo tang dan
p-CH3C6H4NH2(l),
p-N02C6H4NH2(2),
C6H5NH2(3),
n-C6H,3NH2(4)
172


Hogt dgng cua HS

Hogt dgng cUa GV
A.(l),(2),(3),(4)
B.(2),(3),(l),(4)
C(4),(2),(3),(l)
D.(2),(4),(3),(l)
Phieu 4. De trung boa 25 gam dung Dap anC

dich ciia mot amin don chiic X nong dp
12,4% can diing 100ml dung dich HCl
IM. Cong thiic phan tir cua X la
A. C3H5N

B. C3H7N

C. CH5N

D. C2H7N

Bai tap vl nha 1, 2, 3, 4, 5, 6, 7, 8. (SGK)

D. HU'ONG D A N GIAI BAI TAP TRONG SGK
1. Chpn dap an C
2.

X

+ 0 2 ^

CO2

5,9 g

+

6,72 lit

1,12.28

+

8,1 g

N2
1,12 lit

,
8,1.2 . . .
mH = - -18
— = 0,9(gam)

6,72.12
mc= ,_
22,4. =3,6(gam)
mw^

H2O

: 1,4 (gam)

22,4

mo = 5 , 9 - 3 , 6 - 0 , 9 - 1 , 4 = 0
Hgp chat khong chiia oxi. Loai dap an A, B, C
Ggi cong thiic don gian ciia X la CxHyNz, ta co:
X :y :z

3,6 0,9 L4

: ^ = 3:9:1
12 11 14

Cong thiic phan tir ciia X co dang (C3H9N)n voi n = 1 —> C3H9N (chpn C)
a) C3H9N
CH3-CH2-CH2-NH2

CH3-CH2-NH^CH3

Propylamin (bac I)

Etylmetylamin (bac II)

173


CH3-CH-CH2-NH2

CH3-^-CH3

CH3

CH3

Iso propylamin (bac I)

Trimetylamin (bac III)

b) Tuong tu a
c) Co 5 dong phan

NH2

NHo

NH,

NH-CH3

CH2-NH2

CH3
4.

a) HS tu giai.
b) Luc bazo C6H5CH2NH2 > C6H5NH2 do mat dp electron tren nguyen tir N
ciia C6H5CH2NH2 cao hon C6H5NH2.
C6H5CH2NH2 tan v6 ban trong nuoc, lam xanh quy tim do tao lien kit hidro
voi H2O bin hon C6H5NH2.
C6H5NH2 tan trong nuoc kem, khong lam doi mau giiy quy.

5.

Tach hon hgp.
a)
CH4, CH3NH2
+ ddHCldii(r

(2)

CH.!

+NaOH

dd CHjNHj'Cr, HCl du

CHjNH,!

dd NaCl

(1)CH3NH2 +HC1 ^CH3-NH3C1
(2) CH3-NH3CI + NaOH ^ CH3-NH2 + NaCl + H2O

174


b)
OH

NH2

+ ddNaOH
lac dfiu, chiet

CfiHsONafl'^aOH du

C e H j , C6H5NH2
+ dd HCl
lie deu, chiSt

+ SMC CO2 du

C6H5OH

C6H5NH3CI, HCl du

dd NaHC03 CeUe

- dd NaOH du

C6H5NH2

NaCl

(1) C6H5OH + NaOH -^ CeHsONa + H2O
(2) CeHjONa + H2O + CO2 -^ CgHsOH + NaHC03
(3) C6H5NH2 + HCl -^ C6H5NH3CI
(4) C6H5NH3CI + NaOH ^

C6H5NH2 + NaCl + H2O

6. Lap bang
C2H5NH2

C6H5NH2

Cu(0H)2 lie
nhe

C3H5(0H)3

I Ag (nhan ra
dd glucoza)
(pul)

Dd
AgN03/NH3
dun nhe
Nuac Br2

CeHnOa

i tring (pu 2)
(nhan ra anilin)
dd CO mau xanh nhat
(pu 3) (nhan ra
glixerol)

175


1) CsHiiOsCH^O + 2[Ag(NH3)2]OH -^ C5H,,05COONH4 + 2Agi + 3NH3
+ H2O
2) C6H5NH2 + 3Br2 -> C6H2Br3NH2 i + 3HBr
3) 2C3H5(OH)3 + Cu(OH)2 -> [C3H5(OH)20]2Cu 2H2O
b)
CfiHsOH

CH3-NH2
Quy tim

CH3COOH

xanh

Do

dd AgN03/NH3

7.

iAg (pul)

a) Dimg axit de rira Ig dung anilin
C6H5NH2 + H^ ^

C6H5NH3^

b) Diing giam khir cac amin (tao ra cac hgp chat muoi amoni).
8.

C6H5NH2 +HC1 -»C6H5NH3^Cr
1 mol

129,5 g

x = 0,01 mol

1,295 g

C6H5OH + 3Br2 -^ C6H2Br30H i + 3HBr

0,01 mol

0,03 mol

C6H5NH2 + 3Br2 -^ C6H2Br3 NH2 i + 3HBr
0,01 mol

(0,06-0,03) mol

300.3,2 = 100.160 = 0,06 (mol)
[ C 6 H 5 N H 2 ] = ^ = 0,1 (mol/1)

[C6H5OH] = - ^ = 0,1 (mol/1)

176

CH3CHO


Bai 12. AMINO AXIT
A. MUC TIEU BAI HOC
1. Ki§n thiPC
HS biit:
•

Khai niem, ling dung va vai tro amino axit.

•

Dua vao dac diem cau tao de suy ra amino axit vira co tinh axit vira co tinh

bazo.

•

Biet dinh nghia, dieu kien monome ciia phan img triing ngung.

HS hieu: Cau tnic phan tir va tinh chat hoa hgc co ban ciia cac amino axit.

2. KTnang
•

Nhan biet va ggi ten amino axit.

•

Viet cac phuong trinh boa hgc ciia amino axit.

•

Quan sat, giai thich cac thi nghiem chiing minh.

3. Tinh cam, thai do
Amino axit co tam quan trgng trong viec tong hgp ra protein, quyet dinh su
song, khi nam cac tinh chat co ban cua no se tao hiing thu cho HS khi nghien ciiu
bai nay.
Moi quan he giira hgp chat co hai nhom chiic (axit va baza) doi lap nhau lai
ton tai trong mot hgp chat. Se co nhimg tinh chat moi kich thich sir to mo ciia HS
tham gia kham pha.
B. C H U A N B! C U A GV VA

•

GV:

HS

- May tinh, may chieu, cac phieu hpc tap.
- Hinh anh, tranh ve lien quan bai hpc.
- Hoa chit: Quy tim, glyxin, axit glutamic, iysin.
- Dung cu: ong nghiem, cap ong nghiem.

•

HS: On tap kiln thiic ve amin va xem truoc bai amino axit.

177


C. TI^N TRiNH DAY - HOC
Hogt dgng cua GV

Hogt dgng cUa HS
Hogt dgng 1
KIEM TRA B A I CU

GV chieu noi dung bai tap len man HS chuan bi bai.
hinh yeu cau 2 HS len bang trinh bay.
cac HS khac chuan bi de nhan xet va
bo sung.
1. De trung hoa 25 gam dung dich ciia HSl:

mot amin don chirc X nong dp 12,4%)
Tlamin = 3 , l g UHCI = ngmin = 0,1
can diing 100ml dung dich HCl IM.
=> Mamin = 3 1 -^ Dap an C
Cong thiic phan tir ciia X la
A. C3H5N

B. C3H7N

C. CH5N

D. C2H7N

2. cau nao duoi day khong diing?

HS2 chpn dap an B

A. Cac amin deu co tinh bazo
B. Tinh amin ciia tat ca cac bazo deu
manh hon NH3
C.

Anilin CO tinh bazo yeu hon NH3

D. Tat ca cac amin don chiic deu chiia
mot so le nguyen tir H trong phan tir.
I. DINH NGHIA, CAu TAG VA DANH P H A P
Hogt dgng 2
1. DINH NGHIA

,

GV chieu len man hinh cua cac amino HS quan sat, thao luan va nhan xet:
axit.
NH2CH2-COOH

CH3-CH-COOH
NH2

HOCO-CH2-CH2-CH-COOH
NH2

178


Hogt dgng cua GV

Hogt dgng cua HS

Yeu cau HS neu:

Amino axit la hgp chat hiru co tap chirc
ma phan tir chiia dong thoi nhom amino
va nhom cacboxyl

- Khai niem amino axit.
- Cong thiic tong quat.

Cong thiic tong quat la:
(NH2)xR(C00H)y

(x,y>l)

R la goc hidrocacbon
2. CAu

TAO P H A N Tir

GV: Viet cong thiic cau tao cua amino HS thao luan va nhan xet.
axetic NH2-CH2-COOH len bang yeu NH2-CH2-COOH
cau HS nhan xet dac dilm ciu tao, - Co 1 nhom NH2 co tinh bazo.
quan he cua cac nhom chiic.
- Co 1 nhom COOH co tinh axit.
-> hgp chat vira co nhom axit (tinh axit),
vira CO nhom bazo (tinh bazo) se tuong
tac voi nhau.
GV huong dan HS nhan xet
- Dac diem nhom NH2.

HS thao luan va nhan xet: Nhom COOH
cho proton con nhom NH2 nhan nhom
proton cua COOH

- Sir tuong tac giiia 2 nhom.

NH2CH2COOH?=±NH2"CH2COO"+ H^

- Dac diem nhom COOH.

NH2CH2COO"+ H^?=iNH3^CH2COO"

\

Hogt dgng 3
3.DANHPHAP

GV chieu len bang binh 3.2 yeu cau HS quan sat, thao luan
HS nhan xet:
- Co 3 each ggi ten amino axit
- Co bao nhieu each gpi ten amino + Ten thay the: Co cau tnic
axit.
- Quy tac gpi ten ciia moi each
- Cho vi du.

axit + vi tri + amino + ten axit
2

1

CH2-COOH

1

NH2

axit-2-amino etanoic

179


Hogt dgng cUa GV

Hogt dgng cUa HS
CH3 - C H - C H - COOH
CH3 NH2
Axit-2-amino-3-metylbutanoic
+ Ten bdn he thong
Xet vi tri tuong doi ciia nhom amino
trong mach cacbon.
CO

E

5

•y

P

a

C-C-C-C-C-C-COOH
- Quy tac gpi ten
Axit + chii cai vi tri + amino + ten axit
Vidu:
CH2 - COOH axit a-aminoaxetic
NH2
CH3 - CH2 - COOH
NH2

axit a - aminopropionic

HOOCCH2-CH2-CH-COOH
NH2
Axit a-amino glutamic

GV bo sung:

+ Ten thong thuang khong theo quy tac,
gpi theo bang ten rieng.

NH2-CH2-COOH
Glyxin
+ Ten thay the thi axit dugc gpi theo
HS lang nghe va ghi bai.
ten thay the.
+ Ten ban he thong thi axit gpi theo
ten thong thuang.
GV yeu cau HS nam viing cong thiic
cau tao, cac each gpi ten ciia amino
axit thuang gap nhu:
NH2-CH2-COOH axit a-aminoaxetic

180


Hogt dgng cUa GV

Hogt dgng cUa HS

CH3-CH-COOH

NH2

axit a - aminopropionic

NH2(CH2)5-COOH
axit 8-amino caproic
HCOO-CH2-CH2-CH-COOH
NH2
axit a-amino glutamic
Hogt dgng 4
II. TINH C H A T VAT LI
GV nhac lai cau tao cua amino axit yeu HS thao luan va nhan xet.
cau HS du doan tinh chat vat li cua Do cac amino axit la nhung hgp chat ion
amino axit.
luong cue -> 0 dieu kien thuon g la chat
ran ket tinh, de tan trong nuoc CO nhiet
do nong chay cao (tinh chat ciia hgp
chat ion).
HS lang nghe va ghi bai

GV nhan xet va bo sung:
- Amino axit khong bay hoi nong
chay, phan buy b nhiet dp tuong doi
cao.
- Khong tan trong dung moi khong
phan cue nhu diu boa, benzen, ete...ma
tan tot trong nuoc.
- Amino axit thuong co vi ngpt.

Hogt dgng 5

HI. TINH C H A T H O A HOC
GV yeu ciu HS du doan tinh chit h6a HS thao luan va nhan xet:
hpc ciia amino axit.

- Co nhom NH2 co tinh chit cua mot
bazo

181


Hogt dgng cUa GV

Hogt dgng cUa HS

GV chuyen tiep amino axit c6 nhiing - Co nh6m COOH co tinh chit cua mot
tinh chat h6a hgc nao chiing ta se axit-> amino axit co tinh luong tinh.
nghien ciiu cu the timg tinh chit.
1. TINH AXIT-BAZO CUA DUNG DICH AMINO AXIT
GV lam thi nghiem nhiing mau giay HS quan sat, thao luan va giai thich
quy vao dung dich glyxin, axit - Hien tugng:
glutamic, Iysin. Yeu cau HS quan sat
+ Ong dimg dung dich glyxin quy tim
neu hien tugng va giai thich.
khong doi mau.
+ Ong dung dung dich axit glutamic quy
tim boa do.
+ Ong dung dung dich Iysin quy tim hoa
xanh
- Giai thich:
NH2CH2COOH ^^

NH3^CH2COO"

Khong tao ra Y^ hay OH" nen quy
khong doi mau
H2NC3H5(COOH)2 ^=^
%NC3H5(COO~)2 +H^
GV nhan xet bo sung amino axit co Tao ra H"^ lam quy doi mau.
Tuong tu glysin tao ra OH" lam quy hoa
cong thirc (NH2)xR(C00H)y
xanh.
Neu X = y quy tim khong doi mau.
Neu X > y quy tim boa xanh.

HS ghi bai

Neu X < y quy tim boa do.
2. TINH C H A T LirONG TINH
GV yeu cau HS viet phuong trinh boa HS thao luan va nhan xet:
hpc cua glyxin voi HCl, NaOH va nit - Phuong trinh hoa hgc
ra tinh chat chung ciia amino axit.
NH2CH2COOH + HCl ->
CI NH3CH2COOH

182


Hogt dgng cUa HS

Hogt dgng cUa GV

NH2CH2COOH + NaOH -^
NH2CH2COONa + H2O
- Ket luan:
+ Amino axit co nhom -NH2 nen phan
ling dugc voi axit v6 co manh tao muoi.
+ Co nhom -COOH nen phan ling dugc
voi bazo v6 co tao ra muoi va nuoc.
Hogt dgng 6
3. P H A N LTNG ESTE HOA NHOM COOH
GV yeu cau HS viet phan ling este boa HS viet phuong trinh boa hpc.
giiia glyxin voi etanol.
H2N-CH2COOH + C2H5OH
K.ni HLI

GV nhan xet va bo sung:
Thuc ra este dugc hinh thanh duoi
dang muli Cl"NH3^CH2COOC2H5
muon thu dugc este thi:

.

-*TTT r^TT r ^ / ^ r ^ r ^ TT

I TT r^

<
' NH2CH2COOC2H5 + H2O
HS lang nghe va ghi bai.

+ NaOHvua du
-» NH2CH2COOC2H5 + NaCl + H2O
C™H3^CH2C00C2H5

4. P H A N LTNG CUA NHOM NH2 V6l HNO2
GV lam thi nghiem:

HS quan sat va neu hien tugng

Cho vao ong nghiem 2 ml dung dich Co bpt khi khong mau bay len
glyxin 10%), 2ml dung dich NaN02, - Giai thich HNO2 (tao thanh tir NaN02
5-10 gigt axh axetic lac nhe.
+ CH3COOH) phan img voi nhom NH2
Yeu ciu HS quan sat, neu hien tugng. tuong tu amin phan ung giai phong khi
giai thich, vilt phuong trinh boa hpc.
N2.
- Phuong trinh hoa hpc
GV bo sung: Phan ung nay dugc diing H2NCH2COOH + HONO ->
dl dinh lugng nhom amin trong amino
HOCH2COOH + N2 + H2O
axit ciing nhu trong protein.
HS ghi bai.

183