Method of manufacturing diethyl carbonate
View Patent ↗A method manufactures diethyl carbonate by reaction distillation where transesterification and distillation are simultaneously performed in a multistage reaction distillation column provided with a catalyst introduction port and a raw material introduction port located below the catalyst introduction port, wherein: (a) the reaction is performed in a countercurrent flow format in which contact is brought about between a transesterification catalyst, dimethyl carbonate, and ethanol; (e) 1 to 250 mmol of catalyst is used per mole of dimethyl carbonate; (f) the ratio of the volume of air in the catalyst introduction port and the raw material introduction port regarding the volume of air in the reaction distillation part is 0.1 to 0.9; (g) the recirculation ratio in the reaction distillation column is 0.5 to 10; and (h) the temperature of the top part of the column and the reaction distillation part is 60 to 100° C.
1. A method of producing diethyl carbonate by reactive distillation comprising continuously feeding dimethyl carbonate and ethanol into a reactive distillation column to simultaneously carry out transesterification and distillation in the reactive distillation column in the presence of a transesterification catalyst, wherein
(a) transesterification is in a countercurrent reaction mode in which a transesterification catalyst contacts dimethyl carbonate and ethanol;
(b) a reactive distillation column is a multistage reactive distillation column having a column top part, a reaction distillation part having internals, and a concentrating part; and a side of the reaction distillation part is provided with a catalyst introduction port and a raw material introduction port located below the catalyst introduction port;
(c) the transesterification catalyst is fed through the catalyst introduction port;
(d) dimethyl carbonate and ethanol are fed through the raw material introduction port;
(e) an amount of the transesterification catalyst used for 1 mol of dimethyl carbonate is 1 to 250 mmol;
(f) a ratio of the spatial volume between the catalyst introduction port and the raw material introduction port to a spatial volume of the reaction distillation part is 0.1 to 0.9;
(g) a reflux ratio of the reactive distillation column is 0.5 to 10; and
(h) temperature in the column top part and the reaction distillation part is 60° C. to 100° C.
2. The method according to claim 1 , wherein the internals are separated by perforated plate trays.
3. The method according to claim 2 , wherein the number of stages of the reactive distillation column is 30 to 75.
4. The method according to claim 2 , wherein a space between the raw material introduction port and the catalyst introduction port corresponds to 1 to 50 stages.
5. The method according to claim 1 , wherein, in the reactive distillation column, a required number of reaction stages: ΔN defined as the number of stages between the catalyst introduction port and the raw material introduction port satisfies inequality expression (S):
Δ
N
≥
ν
0
V
h
×
Conv
3600
×
exp
(
14.8311
-
5003.61
/
T
)
×
c
B
+
rD
×
(
1
-
Conv
)
(
S
)
where
ΔN: Required number of reaction stages,
v 0 : Total feed volume of dimethyl carbonate, ethanol, and transesterification catalyst to the reactive distillation column per unit time (L·h −1 ),
V h : Hold-up volume per reaction stage (L/number of stages),
Conv: Reaction conversion rate of dimethyl carbonate,
c: Feed amount of catalyst into reactive distillation column (mol·h −1 ),
B: Extraction volume from bottom of reactive distillation column (L·h −1 ),
r: Reflux ratio,
D: Extraction volume from top of reactive distillation column (L·h −1 ), and
T: Column temperature (K).
6. The method according to claim 1 , wherein, in the reactive distillation column, a required reaction distance: ΔL defined as a distance between the catalyst introduction port and the raw material introduction port satisfies inequality expression (W):
Δ
L
≥
ν
0
d
×
Conv
3600
×
exp
(
14.8311
-
5003.61
/
T
)
×
c
B
+
rD
×
(
1
-
Conv
)
(
W
)
where
ΔL: Required reaction distance (m),
v 0 : Total feed volume of dimethyl carbonate, ethanol, and transesterification catalyst to reactive distillation column per unit time (L·h −1 ),
d: Hold-up volume per meter in region between catalyst introduction port and raw material introduction port in reactive distillation column (L·m −1 ),
Conv: Reaction conversion rate of dimethyl carbonate,
c: Feed amount of catalyst into reactive distillation column (mol·h −1 ),
B: Extraction volume from bottom of reactive distillation column (L·h −1 ),
r: Reflux ratio,
D: Extraction volume from top of reactive distillation column (L·h −1 ), and
T: Column temperature (K).
7. The method according to claim 1 , wherein pressure in the column top part and the concentrating part is normal pressure to 1,000 kPa.
8. The method according to claim 1 , wherein the transesterification catalyst is at least one selected from the group consisting of an alkali metal hydroxide, an alkali metal carbonate compound, an alkali metal methoxide, and an alkali metal ethoxide.
9. The method according to claim 3 , wherein a space between the raw material introduction port and the catalyst introduction port corresponds to 1 to 50 stages.
10. The method according to claim 2 , wherein, in the reactive distillation column, a required number of reaction stages: ΔN defined as the number of stages between the catalyst introduction port and the raw material introduction port satisfies inequality expression (S):
Δ
N
≥
ν
0
V
h
×
Conv
3600
×
exp
(
14.8311
-
5003.61
/
T
)
×
c
B
+
rD
×
(
1
-
Conv
)
(
S
)
where
ΔN: Required number of reaction stages,
v 0 : Total feed volume of dimethyl carbonate, ethanol, and transesterification catalyst to the reactive distillation column per unit time (L·h −1 ),
V h : Hold-up volume per reaction stage (L/number of stages),
Conv: Reaction conversion rate of dimethyl carbonate,
c: Feed amount of catalyst into reactive distillation column (mol·h −1 ),
B: Extraction volume from bottom of reactive distillation column (L·h −1 ),
r: Reflux ratio,
D: Extraction volume from top of reactive distillation column (L·h −1 ), and
T: Column temperature (K).
11. The method according to claim 3 , wherein, in the reactive distillation column, a required number of reaction stages: ΔN defined as the number of stages between the catalyst introduction port and the raw material introduction port satisfies inequality expression (S):
Δ
N
≥
ν
0
V
h
×
Conv
3600
×
exp
(
14.8311
-
5003.61
/
T
)
×
c
B
+
rD
×
(
1
-
Conv
)
(
S
)
where
ΔN: Required number of reaction stages,
v 0 : Total feed volume of dimethyl carbonate, ethanol, and transesterification catalyst to the reactive distillation column per unit time (L·h −1 ),
V h : Hold-up volume per reaction stage (L/number of stages),
Conv: Reaction conversion rate of dimethyl carbonate,
c: Feed amount of catalyst into reactive distillation column (mol·h −1 ),
B: Extraction volume from bottom of reactive distillation column (L·h −1 ),
r: Reflux ratio,
D: Extraction volume from top of reactive distillation column (L·h −1 ), and
T: Column temperature (K).
12. The method according to claim 4 , wherein, in the reactive distillation column, a required number of reaction stages: ΔN defined as the number of stages between the catalyst introduction port and the raw material introduction port satisfies inequality expression (S):
Δ
N
≥
ν
0
V
h
×
Conv
3600
×
exp
(
14.8311
-
5003.61
/
T
)
×
c
B
+
rD
×
(
1
-
Conv
)
(
S
)
where
ΔN: Required number of reaction stages,
v 0 : Total feed volume of dimethyl carbonate, ethanol, and transesterification catalyst to the reactive distillation column per unit time (L·h −1 ),
V h : Hold-up volume per reaction stage (L/number of stages),
Conv: Reaction conversion rate of dimethyl carbonate,
c: Feed amount of catalyst into reactive distillation column (mol·h −1 ),
B: Extraction volume from bottom of reactive distillation column (L·h −1 ),
r: Reflux ratio,
D: Extraction volume from top of reactive distillation column (L·h −1 ), and
T: Column temperature (K).
13. The method according to claim 2 , wherein pressure in the column top part and the concentrating part is normal pressure to 1,000 kPa.
14. The method according to claim 3 , wherein pressure in the column top part and the concentrating part is normal pressure to 1,000 kPa.
15. The method according to claim 4 , wherein pressure in the column top part and the concentrating part is normal pressure to 1,000 kPa.
16. The method according to claim 5 , wherein pressure in the column top part and the concentrating part is normal pressure to 1,000 kPa.
17. The method according to claim 6 , wherein pressure in the column top part and the concentrating part is normal pressure to 1,000 kPa.