A partir de derivados halogenados
editar
2
H
3
C
−
C
H
B
r
−
C
H
3
+
2
N
a
→
H
3
C
−
C
H
(
C
H
3
)
−
C
H
(
C
H
3
)
−
C
H
3
+
2
N
a
B
r
{\displaystyle \scriptstyle 2\,H_{3}C-CHBr-CH_{3}\,+2\,Na\rightarrow H_{3}C-CH(CH_{3})-CH(CH_{3})-CH_{3}\,+\,2\,NaBr}
o partiendo de otro 2-halopropano:
(
C
H
3
)
2
C
H
X
+
2
N
a
→
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
N
a
X
{\displaystyle \scriptstyle (CH_{3})_{2}CHX+2\,Na{\xrightarrow {}}(CH_{3})_{2}CHCH(CH_{3})_{2}+NaX}
A partir de un derivado 2-halogenado de propano con litio en presencia de éter etílico y haluro de litio:
(
C
H
3
)
2
C
H
X
+
2
L
i
→
−
L
i
X
|
E
t
2
O
|
(
C
H
3
)
2
C
H
L
i
{\displaystyle \scriptstyle (CH_{3})_{2}CHX+2\,Li{\xrightarrow[{-LiX}]{|Et_{2}O|}}(CH_{3})_{2}CHLi}
que posteriormente:
(
C
H
3
)
2
C
H
L
i
→
+
(
C
H
3
)
2
C
H
X
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
L
i
X
{\displaystyle \scriptstyle (CH_{3})_{2}CHLi{\xrightarrow {+(CH_{3})_{2}CHX}}(CH_{3})_{2}CHCH(CH_{3})_{2}+LiX}
A partir de derivados monohalogenados (como el 1-cloro-2,3-dimetilbutano o el 2-cloro-2,3-dimetilbutano):
1. Tratados con hidrácidos en presencia de zinc :
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
C
H
2
X
+
Z
n
+
H
X
→
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
Z
n
X
2
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})CH_{2}X+Zn+HX{\xrightarrow {}}(CH_{3})_{2}CHCH(CH_{3})_{2}+ZnX_{2}}
ó bien
(
C
H
3
)
2
C
H
C
X
(
C
H
3
)
2
+
Z
n
+
H
X
→
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
Z
n
X
2
{\displaystyle \scriptstyle (CH_{3})_{2}CHCX(CH_{3})_{2}+Zn+HX{\xrightarrow {}}(CH_{3})_{2}CHCH(CH_{3})_{2}+ZnX_{2}}
2. Con tetrahidruro de aluminio y litio, LiAlH4 , o con tetrahidruro de boro y sodio, NaBH4 :
4
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
C
H
2
X
+
L
i
A
l
H
4
→
{\displaystyle \scriptstyle 4\,(CH_{3})_{2}CHCH(CH_{3})CH_{2}X+LiAlH_{4}{\xrightarrow {}}}
4
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
A
l
X
3
+
L
i
X
{\displaystyle \scriptstyle 4\,(CH_{3})_{2}CHCH(CH_{3})_{2}+AlX_{3}+LiX}
o bien
4
(
C
H
3
)
2
C
H
C
X
(
C
H
3
)
2
+
L
i
A
l
H
4
→
4
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
A
l
X
3
+
L
i
X
{\displaystyle \scriptstyle 4\,(CH_{3})_{2}CHCX(CH_{3})_{2}+LiAlH_{4}{\xrightarrow {}}4\,(CH_{3})_{2}CHCH(CH_{3})_{2}+AlX_{3}+LiX}
3. Con hidrácidos como yoduro de hidrógeno :
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
C
H
2
I
+
H
I
→
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
I
2
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})CH_{2}I+HI{\xrightarrow {}}(CH_{3})_{2}CHCH(CH_{3})_{2}+I_{2}}
o bien
(
C
H
3
)
2
C
H
C
I
(
C
H
3
)
2
+
H
I
→
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
I
2
{\displaystyle \scriptstyle (CH_{3})_{2}CHCI(CH_{3})_{2}+HI{\xrightarrow {}}(CH_{3})_{2}CHCH(CH_{3})_{2}+I_{2}}
4. Con litio , en presencia de éter etílico , se forman compuestos de organolitio , y posterior hidrólisis para obtener el 2,3-dimetilbutano.
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
C
H
2
X
+
2
L
i
→
|
E
t
2
O
|
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})CH_{2}X+2Li{\xrightarrow {|Et_{2}O|}}}
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
C
H
2
L
i
+
L
i
X
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})CH_{2}Li+LiX}
y posterior hidrólisis
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
C
H
2
L
i
+
H
2
O
→
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})CH_{2}Li+H_{2}O{\xrightarrow {}}}
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
L
i
O
H
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})_{2}+LiOH}
o bien
C
H
3
C
H
X
C
(
C
H
3
)
3
+
2
L
i
→
|
E
t
2
O
|
{\displaystyle \scriptstyle CH_{3}CHXC(CH_{3})_{3}+2Li{\xrightarrow {|Et_{2}O|}}}
C
H
3
C
H
L
i
C
(
C
H
3
)
3
+
L
i
X
{\displaystyle \scriptstyle CH_{3}CHLiC(CH_{3})_{3}+LiX}
y posterior hidrólisis
C
H
3
C
H
L
i
C
(
C
H
3
)
3
+
H
2
O
→
{\displaystyle \scriptstyle CH_{3}CHLiC(CH_{3})_{3}+H_{2}O{\xrightarrow {}}}
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
L
i
O
H
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})_{2}+LiOH}
5. Con magnesio , en presencia de éter etílico , se forman compuestos de organomagnesio , y posterior hidrólisis para obtener el 2,3-dimetilbutano.
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
C
H
2
X
+
M
g
→
|
E
t
2
O
|
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})CH_{2}X+Mg{\xrightarrow {|Et_{2}O|}}}
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
C
H
2
M
g
X
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})CH_{2}MgX}
y posterior hidrólisis
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
C
H
2
M
g
X
+
H
2
O
→
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})CH_{2}MgX+H_{2}O{\xrightarrow {}}}
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
M
g
(
O
H
)
X
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})_{2}+Mg(OH)X}
o bien
C
H
3
C
H
X
C
(
C
H
3
)
3
+
M
g
→
|
E
t
2
O
|
{\displaystyle \scriptstyle CH_{3}CHXC(CH_{3})_{3}+Mg{\xrightarrow {|Et_{2}O|}}}
(
C
H
3
)
2
C
H
C
(
M
g
X
)
(
C
H
3
)
2
{\displaystyle \scriptstyle (CH_{3})_{2}CHC(MgX)(CH_{3})_{2}}
y posterior hidrólisis
(
C
H
3
)
2
C
H
C
(
M
g
X
)
(
C
H
3
)
2
+
H
2
O
→
{\displaystyle \scriptstyle (CH_{3})_{2}CHC(MgX)(CH_{3})_{2}+H_{2}O{\xrightarrow {}}}
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
M
g
(
O
H
)
X
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})_{2}+Mg(OH)X}
1. A partir de 2,3-dimetil-2-buteno, usando níquel como catalizador ::
(
C
H
3
)
2
C
=
C
(
C
H
3
)
2
+
H
2
→
N
i
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
{\displaystyle \scriptstyle (CH_{3})_{2}C=C(CH_{3})_{2}+H_{2}{\xrightarrow {Ni}}(CH_{3})_{2}CHCH(CH_{3})_{2}}
2. A partir de 2,3-dimetil-1,3-butadieno, usando níquel como catalizador :
C
H
2
=
C
(
C
H
3
)
C
(
C
H
3
)
=
C
H
2
+
2
H
2
→
N
i
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
{\displaystyle \scriptstyle CH_{2}=C(CH_{3})C(CH_{3})=CH_{2}+2H_{2}{\xrightarrow {Ni}}(CH_{3})_{2}CHCH(CH_{3})_{2}}
A partir de aldehídos
editar
Por tratamiento del aldehído 2,3-dimetilbutanal con hidrazina , (reacción de Wolf-Kishner):
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
C
H
O
+
N
H
2
N
H
2
→
K
O
H
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
N
2
+
H
2
O
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})CHO+NH_{2}NH_{2}{\xrightarrow {KOH}}(CH_{3})_{2}CHCH(CH_{3})_{2}+N_{2}+H_{2}O}
1. Por hidrólisis de 3,4-dimetilpentanoato sódico, (CH3 )2 CΗCΗ(CH3 )CH2 COONa, en caliente:
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
C
H
2
C
O
O
N
a
+
H
2
O
→
4
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
N
a
H
C
O
3
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})CH_{2}COONa+H_{2}O{\xrightarrow {\mathcal {4}}}(CH_{3})_{2}CHCH(CH_{3})_{2}+NaHCO_{3}}
El NaHCO3 formado se descompone en NaOH y CO2 por lo que la reacción resultante es:
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
C
H
2
C
O
O
N
a
+
H
2
O
→
4
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
N
a
O
H
+
C
O
2
{\displaystyle \scriptstyle (CH_{3})_{2}CHCH(CH_{3})CH_{2}COONa+H_{2}O{\xrightarrow {\mathcal {4}}}(CH_{3})_{2}CHCH(CH_{3})_{2}+NaOH+CO_{2}}
2. Por hidrólisis de 2,2,3-trimetilbutanoato sódico, (CH3 )2 CHC(CH3 )2 COONa en caliente:
(
C
H
3
)
2
C
H
C
(
C
H
3
)
2
C
O
O
N
a
+
H
2
O
→
4
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
N
a
H
C
O
3
{\displaystyle \scriptstyle (CH_{3})_{2}CHC(CH_{3})_{2}COONa+H_{2}O{\xrightarrow {\mathcal {4}}}(CH_{3})_{2}CHCH(CH_{3})_{2}+NaHCO_{3}}
Igualmente, el NaHCO3 formado se descompone en NaOH y CO2 , por lo que globalmente resulta:
(
C
H
3
)
2
C
H
C
(
C
H
3
)
2
C
O
O
N
a
+
H
2
O
→
4
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
N
a
O
H
+
C
O
2
{\displaystyle \scriptstyle (CH_{3})_{2}CHC(CH_{3})_{2}COONa+H_{2}O{\xrightarrow {\mathcal {4}}}(CH_{3})_{2}CHCH(CH_{3})_{2}+NaOH+CO_{2}}
Síntesis industrial
editar
1. Obtención de haluro de etilo por reacción de hidrácido (ΗΧ) con etileno , C2 H4 :
C
H
2
=
C
H
2
+
H
X
→
C
H
3
C
H
2
X
{\displaystyle \scriptstyle CH_{2}=CH_{2}+HX{\xrightarrow {}}CH_{3}CH_{2}X}
2. Tratamiento con cianuro sódico y obtención de propanonitrilo:
C
H
3
C
H
2
X
+
N
a
C
N
→
C
H
3
C
H
2
C
N
+
N
a
X
{\displaystyle \scriptstyle CH_{3}CH_{2}X+NaCN{\xrightarrow {}}CH_{3}CH_{2}CN+NaX}
3. Obtención de ácido propanoico por hidrólisis:
C
H
3
C
H
2
C
N
+
2
H
2
O
→
C
H
3
C
H
2
C
O
O
H
+
N
H
3
{\displaystyle \scriptstyle CH_{3}CH_{2}CN+2H_{2}O{\xrightarrow {}}CH_{3}CH_{2}COOH+NH_{3}}
4. Reducción del ácido propanoico por LiAlH4 y obtención de propan-1-ol :
2
C
H
3
C
H
2
C
O
O
H
+
L
i
A
l
H
4
→
2
C
H
3
C
H
2
C
H
2
O
H
+
L
i
A
l
O
2
{\displaystyle \scriptstyle 2\,CH_{3}CH_{2}COOH+LiAlH_{4}{\xrightarrow {}}2\,CH_{3}CH_{2}CH_{2}OH+LiAlO_{2}}
5. Deshidratación con ácido sulfúrico en caliente y obtención de propeno :
C
H
3
C
H
2
C
H
2
O
H
→
170
o
C
π
.
H
2
S
O
4
C
H
3
C
H
=
C
H
2
+
H
2
O
{\displaystyle \scriptstyle CH_{3}CH_{2}CH_{2}OH{\xrightarrow[{170^{o}C}]{\pi .H_{2}SO_{4}}}CH_{3}CH=CH_{2}+H_{2}O}
6. Tratamientocon hidrácido y obtención de monoderivado halogenado, preferentemente en el carbono secundario (2-haluro de alquilo):
C
H
3
C
H
=
C
H
2
+
H
X
→
C
H
3
C
H
X
C
H
3
{\displaystyle \scriptstyle CH_{3}CH=CH_{2}+HX{\xrightarrow {}}CH_{3}CHXCH_{3}}
7. Tratamiento con sodio (síntesis de Wurtz ):
(
C
H
3
)
2
C
H
X
+
2
N
a
→
(
C
H
3
)
2
C
H
C
H
(
C
H
3
)
2
+
N
a
X
{\displaystyle \scriptstyle (CH_{3})_{2}CHX+2Na{\xrightarrow {}}(CH_{3})_{2}CHCH(CH_{3})_{2}+NaX}