Question

89. Formeaza prin hidroliza bazica acetaldehida:
A. Anhidrida acetica
B. Acetat de etil
C. Acetamida
D. Dietileter
E. Acetat de vinil

30. Tratarea unui alcool cu anhidrida acetica in exces duce la cresterea masei moleculare cu 126 g , crestere reprezentand 136,95%. Alcoolul este: etanol, glicerina, glicol , butantriol, butanol

Answer 1

89:
a) (CH3CO)2O + H2O => 2 CH3COOH
b) CH3COO-CH2-CH3 + H2O => CH3COOH + CH3CH2OH
c) CH3CONH2 + H2O => CH3COOH + NH3
d) CH3CH2OCH2CH3 + H2O => 2 CH3CH2OH
e) CH3COOCH=CH2 + H2O => CH3COOH + CH2=CH-OH (prin tautomerizare=>acetaldehida)
30:
Formula moleculara alcool: CnH2n+2Ox
Reactia: CnH2n+2Ox + y (CH3CO)2O => CnH(2n+2-y)Ox -(CO-CH3)y + y CH3COOH
masa moleculara alcool=14n+2+16x
masa moleculara ester=14n+2-y+16x+43y
=>14n+2+16x+126=14n+2-y+16x+43y=>126=42y
=>y=3=>se aditioneaza 3 moli de anhidrida
=>x=3=>se acileaza 3 grupe hidroxil
%crestere=m adaugata/m moleculara alcool*100
=>136,95=42y/(14n+2+16*3)*100=>4200y=1917.3n+6847.5=>1917,3n=4200*3-6847,5=>n=3=>C3H8O3=>glicerina
Raspunsuri:
89: Acetatul de vinil prin hidroliza bazica formeaza acetaldehida
90: Alcoolul este glicerina