CA1047964A - Method of separating diacetoxybutene - Google Patents
Method of separating diacetoxybuteneInfo
- Publication number
- CA1047964A CA1047964A CA221,902A CA221902A CA1047964A CA 1047964 A CA1047964 A CA 1047964A CA 221902 A CA221902 A CA 221902A CA 1047964 A CA1047964 A CA 1047964A
- Authority
- CA
- Canada
- Prior art keywords
- tower
- distillation
- torr
- acetic acid
- diacetoxybutene
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
- C07C67/54—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation by distillation
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention provides a method of separating diacetoxybutene form a reaction mixture produced by reacting butadiene, acetic acid and a molecular oxygen, which comprises subjecting said mixture to distillation in a distillation tower and maintaining the temperature of the bottom at the tower at lower than 190°C by controlling the internal pressure of the distillation tower.
The present invention provides a method of separating diacetoxybutene form a reaction mixture produced by reacting butadiene, acetic acid and a molecular oxygen, which comprises subjecting said mixture to distillation in a distillation tower and maintaining the temperature of the bottom at the tower at lower than 190°C by controlling the internal pressure of the distillation tower.
Description
1~'i'9t;qL
Th~ pr~ nt .inv~nk:i.on ~ L~tc!.~, to ~ m~thocl of separa-ting diace-toxybutene. More particu].a.rly, the preserlt invention relates to a method of separating cliace toxybu tene ~:rorn a reaCtion product ohtained by reac-king butadiene, acetic acid and molecular oxygen ~/a~/0h by di~ti~. ~:
Diacetoxybutene is an important reac-tant for producing butanediol which material is an important solvent and raw :-material for various industrial chemicals.
Various methods of producing diacetoxybutene have been :
proposed. A typical method has been to react butadiene, acetic acid and oxygen or an oxygen-containing gas in the presence of the palladium type catalyst. It has been necessary to separate~
diacetoxybutene from the reaction mixture obtained by this acetoxylation reaction. However, both the unreacted material and :~
the product diacetoxybutene have an unsaturated radical, and ~.
accordingly polymerization of the compounds is easily caused by ~
certain separating procedures decreasing the yield and causing .-i Prol~Je ~5 operational ti~u~s. Various methods of separating diacetoxy- ~ :
butenes from the reaction mixture ~ the acetoxylation reaction have been studied. and, it has been found that diacetoxybutenes ;~ ;
are easily decomposea or polymerized at temperatures higher than ~ a specific temperature and are relatively stable at a~temperature lower than this specific temperature.
The present invention thus provides a method oE
separating diacetoxybutenes from the reaction mixture produced by the above acetoxylation reaction, in high yield with smooth operation.
~ According to the present invention there is provided a method of separating diacetoxybutene from a reaction mixture produced by~reaction butadiene, acetic acid, and a molecular ox~-gen in the presence o~ the palladium type catalyst, which method -~
comprises distillLng the mixture in at least one distillation ~ .
: . . :
:
- 1~4~9~4 tower and main-tainincJ the temp~ratur~ at the bottorn of &~
~ o~r ~d~t:~Y~ lower -than 190C by con-trolling -the :internal presswre of the distillation tower.
The reaction m:Lxture used in the process of the present invention is produced by acetoxylation in which butadiene, acetic acid and a molecular oxygen are reacted in the presence of a palladium type catalyst.
The acetoxylation reaction may be conducted by known methods. Butadiene used as a starting material for acetoxylation reaction can be pure compound and also a mixture of butadiene and -other saturated hydrocarbonsJ such as methane, ethane and butane can be used. Acetic acid used as the other starting material is preferably used in anhydrous condition.
The catalyst used for the reaction is preferably ;~
palladium metal or palladium metal and at least one of promoter metal selected from bismuth, selenium, antimony or tellurium supported in a carriex. The carrier may be active carbon, silica geL, silica-alumina, alumina, clay, bauxite, magnesia, i~
diatomaceous earth or pumice. The amount of~the catalytic metal -~
in the catalyst is usually 0.1 - 20 wt.~ of palladium metal and 0.01 - 30 wt.% of a promoter metal. The reactlon can be conducted by desirable system such as a fixed bed system, a fluidized bed system or a suspending~catalyst system.
The molecular oxygen fed into the reaction system includes pure oxygen or oxygen diluted with an inert gas such as air. The reaction can be conducted at a temperature from 40 - 180C
preferably from 60 - 150C under super atmospheric pressure.
The product acetoxylation reaction mixture contains unreacted butadiene. Accordingly, it is preferable to use the.
reaction mixture after removing butadiene and other impurities having boiling points similar to the boiling point of butadiene, by a degasi~ication. After the degasification, the reaction mLxture
Th~ pr~ nt .inv~nk:i.on ~ L~tc!.~, to ~ m~thocl of separa-ting diace-toxybutene. More particu].a.rly, the preserlt invention relates to a method of separating cliace toxybu tene ~:rorn a reaCtion product ohtained by reac-king butadiene, acetic acid and molecular oxygen ~/a~/0h by di~ti~. ~:
Diacetoxybutene is an important reac-tant for producing butanediol which material is an important solvent and raw :-material for various industrial chemicals.
Various methods of producing diacetoxybutene have been :
proposed. A typical method has been to react butadiene, acetic acid and oxygen or an oxygen-containing gas in the presence of the palladium type catalyst. It has been necessary to separate~
diacetoxybutene from the reaction mixture obtained by this acetoxylation reaction. However, both the unreacted material and :~
the product diacetoxybutene have an unsaturated radical, and ~.
accordingly polymerization of the compounds is easily caused by ~
certain separating procedures decreasing the yield and causing .-i Prol~Je ~5 operational ti~u~s. Various methods of separating diacetoxy- ~ :
butenes from the reaction mixture ~ the acetoxylation reaction have been studied. and, it has been found that diacetoxybutenes ;~ ;
are easily decomposea or polymerized at temperatures higher than ~ a specific temperature and are relatively stable at a~temperature lower than this specific temperature.
The present invention thus provides a method oE
separating diacetoxybutenes from the reaction mixture produced by the above acetoxylation reaction, in high yield with smooth operation.
~ According to the present invention there is provided a method of separating diacetoxybutene from a reaction mixture produced by~reaction butadiene, acetic acid, and a molecular ox~-gen in the presence o~ the palladium type catalyst, which method -~
comprises distillLng the mixture in at least one distillation ~ .
: . . :
:
- 1~4~9~4 tower and main-tainincJ the temp~ratur~ at the bottorn of &~
~ o~r ~d~t:~Y~ lower -than 190C by con-trolling -the :internal presswre of the distillation tower.
The reaction m:Lxture used in the process of the present invention is produced by acetoxylation in which butadiene, acetic acid and a molecular oxygen are reacted in the presence of a palladium type catalyst.
The acetoxylation reaction may be conducted by known methods. Butadiene used as a starting material for acetoxylation reaction can be pure compound and also a mixture of butadiene and -other saturated hydrocarbonsJ such as methane, ethane and butane can be used. Acetic acid used as the other starting material is preferably used in anhydrous condition.
The catalyst used for the reaction is preferably ;~
palladium metal or palladium metal and at least one of promoter metal selected from bismuth, selenium, antimony or tellurium supported in a carriex. The carrier may be active carbon, silica geL, silica-alumina, alumina, clay, bauxite, magnesia, i~
diatomaceous earth or pumice. The amount of~the catalytic metal -~
in the catalyst is usually 0.1 - 20 wt.~ of palladium metal and 0.01 - 30 wt.% of a promoter metal. The reactlon can be conducted by desirable system such as a fixed bed system, a fluidized bed system or a suspending~catalyst system.
The molecular oxygen fed into the reaction system includes pure oxygen or oxygen diluted with an inert gas such as air. The reaction can be conducted at a temperature from 40 - 180C
preferably from 60 - 150C under super atmospheric pressure.
The product acetoxylation reaction mixture contains unreacted butadiene. Accordingly, it is preferable to use the.
reaction mixture after removing butadiene and other impurities having boiling points similar to the boiling point of butadiene, by a degasi~ication. After the degasification, the reaction mLxture
- 2 -: L~47g~;~
contains 1,4-diacetoxybuten~ and isomerg oE d:iacetoxybutenes, .
water, acetic acid and the other high boiliny point materials.
The amounts of these materials in the reaction mixture are dependent upon the reactlon conditions and are relatively hard to define. Thus, the amount of butadiene derlvatives including diacetoxybutenes and high boiling point materials may be 0.5 -50 wt % and the amount of water may be 0.05 - 20 %. The amounts of diacetoxybutenes in the butadiene derivatives may be 50 - 95 ~ ~
wt % o~ 1,4-diacetoxybutene; 5 - 45 wt ~ of isomers of diacetoxy- ~ ~-butene and 0.1 - 10 wt % of high hoiling point materials based on the total weight of the butadiene derivatives.
rl~he reaction mixture is dist:illed in accordance with the method of the present invention. It is preferable to employ series of plural distillation towers. For example, when diace-toxybutenes are separated, a distillation tower for water and acetic acid (referred to as tower A) and a distillation tower for high boiling point materials (referred to as tower C) are employed in a~alternative arrangement of towers A - C or towers C - A. Thus, it is preferable to dispose the towers in A - C
arrangement because the high boiling point materials produced in the distillation can be separated to a higher degree. When 1,4-diacetoxybutene is separated, it is usual to employ a distilla-tion tower for isomers of diacetoxybutene (referred to as tower B) In such a case, it is possible to dispose the towers in the order A - B - C, C - A B or A - C - B. It is preferable to operate with the A - B - C arrangement or towers. It is possible to employ both of an atmospheric pressure tower and a reduced pressure tower as the tower A;
In the distlllation process of the present invention, it is necessary to maintain the temperatures at all tower bottoms at less than 190C, because the thermal stability of the diacetoxybutene-containing material is remarkably decreased at a temperature ~1~)4'7~
~;gher than speciEic temper~lture as shown in 'rahle 1. 'rhe boiling point oE 1,4~cliacetoxy~utene-2 :is 222-230C at: ~tmospheric pressure and the boiling poi.nt o~ 3,4-d:iacetoxybutene-1 iS 206-208C ~t atmospheric pressure.
In the fractional distilla-tion of diacetoxybutenes, the sepaxation of cis compound and trans-compound is not considered, but 1,4-diacetoxybutene-2 can be separated from 3,4-diacetoxy-butene-l at a temperature lower than 190C under reduced pressure.
In tower A water a~d acetic acid are dis-tilled of-f from the top to leave diacetoxybutenes in the bottom. In tower C the diacetoxybutenes (or separated 1,4-diacetoxybuten-2) are distilled off to leave high boiling point materials in the bottom. The distillations are conducted under suitable reduced pressures so as ^-.
to maintain the temperature of the tower bottoms at lower than 190C usually from 120 - 190C and preferably 140 - 180C.
The red~ced pressures at the tops of the towers ;~
(referred to as operation pressure ) are as follows~
~' ; usual range preferable range ~ Tower A ~ 30 - 250 Torr 30 -~150 Torr 20~ Tower B ; ~ 10 - 230 Trr 10 -~100 Trr Tower~C ~ ~ - 100 Torr 5 50 Torr , Experiment] . ~ ' :
-A condenser~;made of Pyrex ( a trademark ) glass and a ;~
thermometer for measuring internal temperature are connected to a three necked flask made of Pyrex ( a trademark j glass having , volume of 300 mQ and a pipe for nitrogen supply is connected to the top of the condenser. ach of 150 g of diacetoxybutene-containing solution having the following formulation was charged in the flasX.
Nitrogen was bubbled through so as to purge air and the flask was -. -sealed. The flask was heated to a particular temperature by heating the heat transfer medium and was maintained at -that .~ :
- 4 - ;~
~ 4t7g~;4 temperature for lo hours, ~nd then w~s coole~ to the roor~
temp~rature.
A part of the product was sampled and was analyzed by a gas chromatography.
Formulation of sample Sarnple I: ~
wt.% - ;
1,4-diacetoxybutene-2 79.6 ~ ~;
contains 1,4-diacetoxybuten~ and isomerg oE d:iacetoxybutenes, .
water, acetic acid and the other high boiliny point materials.
The amounts of these materials in the reaction mixture are dependent upon the reactlon conditions and are relatively hard to define. Thus, the amount of butadiene derlvatives including diacetoxybutenes and high boiling point materials may be 0.5 -50 wt % and the amount of water may be 0.05 - 20 %. The amounts of diacetoxybutenes in the butadiene derivatives may be 50 - 95 ~ ~
wt % o~ 1,4-diacetoxybutene; 5 - 45 wt ~ of isomers of diacetoxy- ~ ~-butene and 0.1 - 10 wt % of high hoiling point materials based on the total weight of the butadiene derivatives.
rl~he reaction mixture is dist:illed in accordance with the method of the present invention. It is preferable to employ series of plural distillation towers. For example, when diace-toxybutenes are separated, a distillation tower for water and acetic acid (referred to as tower A) and a distillation tower for high boiling point materials (referred to as tower C) are employed in a~alternative arrangement of towers A - C or towers C - A. Thus, it is preferable to dispose the towers in A - C
arrangement because the high boiling point materials produced in the distillation can be separated to a higher degree. When 1,4-diacetoxybutene is separated, it is usual to employ a distilla-tion tower for isomers of diacetoxybutene (referred to as tower B) In such a case, it is possible to dispose the towers in the order A - B - C, C - A B or A - C - B. It is preferable to operate with the A - B - C arrangement or towers. It is possible to employ both of an atmospheric pressure tower and a reduced pressure tower as the tower A;
In the distlllation process of the present invention, it is necessary to maintain the temperatures at all tower bottoms at less than 190C, because the thermal stability of the diacetoxybutene-containing material is remarkably decreased at a temperature ~1~)4'7~
~;gher than speciEic temper~lture as shown in 'rahle 1. 'rhe boiling point oE 1,4~cliacetoxy~utene-2 :is 222-230C at: ~tmospheric pressure and the boiling poi.nt o~ 3,4-d:iacetoxybutene-1 iS 206-208C ~t atmospheric pressure.
In the fractional distilla-tion of diacetoxybutenes, the sepaxation of cis compound and trans-compound is not considered, but 1,4-diacetoxybutene-2 can be separated from 3,4-diacetoxy-butene-l at a temperature lower than 190C under reduced pressure.
In tower A water a~d acetic acid are dis-tilled of-f from the top to leave diacetoxybutenes in the bottom. In tower C the diacetoxybutenes (or separated 1,4-diacetoxybuten-2) are distilled off to leave high boiling point materials in the bottom. The distillations are conducted under suitable reduced pressures so as ^-.
to maintain the temperature of the tower bottoms at lower than 190C usually from 120 - 190C and preferably 140 - 180C.
The red~ced pressures at the tops of the towers ;~
(referred to as operation pressure ) are as follows~
~' ; usual range preferable range ~ Tower A ~ 30 - 250 Torr 30 -~150 Torr 20~ Tower B ; ~ 10 - 230 Trr 10 -~100 Trr Tower~C ~ ~ - 100 Torr 5 50 Torr , Experiment] . ~ ' :
-A condenser~;made of Pyrex ( a trademark ) glass and a ;~
thermometer for measuring internal temperature are connected to a three necked flask made of Pyrex ( a trademark j glass having , volume of 300 mQ and a pipe for nitrogen supply is connected to the top of the condenser. ach of 150 g of diacetoxybutene-containing solution having the following formulation was charged in the flasX.
Nitrogen was bubbled through so as to purge air and the flask was -. -sealed. The flask was heated to a particular temperature by heating the heat transfer medium and was maintained at -that .~ :
- 4 - ;~
~ 4t7g~;4 temperature for lo hours, ~nd then w~s coole~ to the roor~
temp~rature.
A part of the product was sampled and was analyzed by a gas chromatography.
Formulation of sample Sarnple I: ~
wt.% - ;
1,4-diacetoxybutene-2 79.6 ~ ~;
3,4-diacetoxybutene-1 10.2 acetlc acid 8.2 ~
. other 2 . O :~ .
Sample II:
1,4-diacetoxybutene-2 98.5wt-%
other 1.5 : -~ TabIe 1 Maintalned 180C 200C210-23ZC
tempera~ture ~ Temperature of `heat~transfer medium 191 - 193 211-213 250-260 Sample I ~ 99.8 99.0 ~85.0 Sample~II 99.6 94.0 :: ~
In Table l/ the amount of diacetoxybutenes after heating the temperature to 100% of diacetoxybutenes in the sample be~ore heating, was started. `~
a~
Accordingly, when the temperature ~ the tower ~ .
'~i bottom is higher than 190C, in the distillation, the production of~low boiling point materials is caused by the decomposition of diaceto~ybutenes and the production of high boiling point `
:
materials is~caused by polymerization of diacetoxybutenes, whereby the distillation loss of diacetoxybutenes is so high as to be economically disadvantageous. It is hard to maintain stable .: .
:
.. , ~
1~479~4 distlllation operation, because o~ the production of the low boilin~ poin-t materials and the adhesion o:E the high boiling point materials on the heating surface. When the amount of the -:
high boiling point materials is increased, it is necessary to increase the temperature of the tower bottom for effectively distilling diacetoxybutene. At a higher temperature, the production of the high boiling point materials is disadvanta- ~-geously promoted, whereby the loss of diacetoxybutenes is dis-advantageously increased. ~:~
Thus, it is necessary to maintain the temperature lower than 190C and it is preferable to maintain the temperature ::
: in the range 190 - 120C. At lower than 120C, the operating pressure of the tower is lower than 10 Torr which is disadvan- .~ :
tageous for 3n industrial operation. The temperature of the top of the toweris decreased whence acetic acid and 1,4-diacetoxy- .
butene may be condensed in the condenser. The operating condi-tions of the distillation tower suitably are the temperature of : .: , :
the bottom of the tower from 120 - 190C; and the operating .: .
pressure of 30 - 250 Torr in tower A; 10 - 230 Torr in tower B; ;
and 2 - 100 Torr in Tower C. It is possible to operate it out- .
side the ranges, for example, under the atmospheric pressure in tower A so as~to increase the concentration of diacetoxybutene.
As stated above, in accordance with the method of the -~
invention, the temperatures of the bottom of each is tower main- . ;
tained at lower than the specific temperature in the separation :
: of the diacetoxybutene by distilling the acetoxylation reaction ~:
mixture, whereby the side-reactions.of decomposition or polymer- ;:
ization of the product is prevented, so as to effectively oktain the desired product The present invention will be further illustrated by :
-~ ~ way of the following Examples: ~
.
,.
~47g64 ~Ex.~ple l]
A sieve-tray -type distillation glass tower ~
h~ving 13 plates was used as tower A. ~ sieve-tray -type glass distilla-tion tower oE glass having 25 pla-tes was used as tower C.
An acetoxylation reaction mixture was continuously distilled under the following conditions to obtain diacetoxybutenes in a yield of 98~
The acetoxylation reaction mix-ture was produced by reacting butadiene, acetic acid and oxygen in the presencé of the catalyst which is palladium and antimony supported on active carbon (10 m mol Pd/100 g active carbon and 3 m mol Sb/100 g active carbon).
- The mixture contained 36~3 wt.% of diacetoxybutenes 0.7 wt.~ of high boiling point materials and acetic acid and small amount of low boiling point impurities.-- Operation conditions ; Tower A Tower C
. .
Temperature of tower bottom 158 - 162C 177 - 182C
. ~ . . ., Operation pressure at tower top 74 Torr 70 Torr . . . :~
Residence time in tower bottom about 2 houFs about 10 hours Ratio of recycling 0.5 1.0 ~ ¦
.
(Reference) The same acétoxylation reaction mixture was continuously distilled under the following conditions by employing the same distillation towers.
~s the results, the resulting diacetoxybutenes discharged from the tower bottom of tower A were colored and had high viscosity.
' - 7 ~
Accor(li.ncl:ly, the operat.iorl :in tow~r C w~-s qu.ite difficult. rrhe yield o:E cl:Lacetoxybutenes was 54 %.
: ., - Tower A Tower C
_ _ , Temperature of tower bo-ttom 215 - 225~C 190 - 200C
Opexation pressure in tower top 420 Torr 135 Torr . Residence time in tower bottom about 2 hours about 2 hours ~
Ratio of recycling ¦ 0.5 1.0 :
. .
~ ~ ' '' -.
. -~, ,.:,:
~2;0-: ~
: ' . ';.' ~:
: --~ ', ' ,, -! ~
:~''' ' : - 8 - ~
. other 2 . O :~ .
Sample II:
1,4-diacetoxybutene-2 98.5wt-%
other 1.5 : -~ TabIe 1 Maintalned 180C 200C210-23ZC
tempera~ture ~ Temperature of `heat~transfer medium 191 - 193 211-213 250-260 Sample I ~ 99.8 99.0 ~85.0 Sample~II 99.6 94.0 :: ~
In Table l/ the amount of diacetoxybutenes after heating the temperature to 100% of diacetoxybutenes in the sample be~ore heating, was started. `~
a~
Accordingly, when the temperature ~ the tower ~ .
'~i bottom is higher than 190C, in the distillation, the production of~low boiling point materials is caused by the decomposition of diaceto~ybutenes and the production of high boiling point `
:
materials is~caused by polymerization of diacetoxybutenes, whereby the distillation loss of diacetoxybutenes is so high as to be economically disadvantageous. It is hard to maintain stable .: .
:
.. , ~
1~479~4 distlllation operation, because o~ the production of the low boilin~ poin-t materials and the adhesion o:E the high boiling point materials on the heating surface. When the amount of the -:
high boiling point materials is increased, it is necessary to increase the temperature of the tower bottom for effectively distilling diacetoxybutene. At a higher temperature, the production of the high boiling point materials is disadvanta- ~-geously promoted, whereby the loss of diacetoxybutenes is dis-advantageously increased. ~:~
Thus, it is necessary to maintain the temperature lower than 190C and it is preferable to maintain the temperature ::
: in the range 190 - 120C. At lower than 120C, the operating pressure of the tower is lower than 10 Torr which is disadvan- .~ :
tageous for 3n industrial operation. The temperature of the top of the toweris decreased whence acetic acid and 1,4-diacetoxy- .
butene may be condensed in the condenser. The operating condi-tions of the distillation tower suitably are the temperature of : .: , :
the bottom of the tower from 120 - 190C; and the operating .: .
pressure of 30 - 250 Torr in tower A; 10 - 230 Torr in tower B; ;
and 2 - 100 Torr in Tower C. It is possible to operate it out- .
side the ranges, for example, under the atmospheric pressure in tower A so as~to increase the concentration of diacetoxybutene.
As stated above, in accordance with the method of the -~
invention, the temperatures of the bottom of each is tower main- . ;
tained at lower than the specific temperature in the separation :
: of the diacetoxybutene by distilling the acetoxylation reaction ~:
mixture, whereby the side-reactions.of decomposition or polymer- ;:
ization of the product is prevented, so as to effectively oktain the desired product The present invention will be further illustrated by :
-~ ~ way of the following Examples: ~
.
,.
~47g64 ~Ex.~ple l]
A sieve-tray -type distillation glass tower ~
h~ving 13 plates was used as tower A. ~ sieve-tray -type glass distilla-tion tower oE glass having 25 pla-tes was used as tower C.
An acetoxylation reaction mixture was continuously distilled under the following conditions to obtain diacetoxybutenes in a yield of 98~
The acetoxylation reaction mix-ture was produced by reacting butadiene, acetic acid and oxygen in the presencé of the catalyst which is palladium and antimony supported on active carbon (10 m mol Pd/100 g active carbon and 3 m mol Sb/100 g active carbon).
- The mixture contained 36~3 wt.% of diacetoxybutenes 0.7 wt.~ of high boiling point materials and acetic acid and small amount of low boiling point impurities.-- Operation conditions ; Tower A Tower C
. .
Temperature of tower bottom 158 - 162C 177 - 182C
. ~ . . ., Operation pressure at tower top 74 Torr 70 Torr . . . :~
Residence time in tower bottom about 2 houFs about 10 hours Ratio of recycling 0.5 1.0 ~ ¦
.
(Reference) The same acétoxylation reaction mixture was continuously distilled under the following conditions by employing the same distillation towers.
~s the results, the resulting diacetoxybutenes discharged from the tower bottom of tower A were colored and had high viscosity.
' - 7 ~
Accor(li.ncl:ly, the operat.iorl :in tow~r C w~-s qu.ite difficult. rrhe yield o:E cl:Lacetoxybutenes was 54 %.
: ., - Tower A Tower C
_ _ , Temperature of tower bo-ttom 215 - 225~C 190 - 200C
Opexation pressure in tower top 420 Torr 135 Torr . Residence time in tower bottom about 2 hours about 2 hours ~
Ratio of recycling ¦ 0.5 1.0 :
. .
~ ~ ' '' -.
. -~, ,.:,:
~2;0-: ~
: ' . ';.' ~:
: --~ ', ' ,, -! ~
:~''' ' : - 8 - ~
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of separating diacetoxybutene from a reaction mixture produced by reacting butadiene, acetic acid and a molecular oxygen, which comprises subjecting said mixture to sequential distillation in at least two distillation towers, main-taining the temperature of the bottom of each tower lower than 190°C by controlling the internal pressure of the distillation tower, a first tower of water and acetic acid being distilled and in a second sequential tower high boiling point materials being separated.
2. A method according to claim 1, wherein the temper-ature of the bottom of each tower is in a range of 190 - 120°C.
3. A method according to claim 1 wherein the temper-ature of the bottom of each tower is in a range of 190 - 120°C
and the operating pressure is 30 - 250 Torr in the first tower for distillation of water and acetic acid and the operating pressure is in the range 2 - 100 Torr in the second tower for separation of high boiling point materials.
and the operating pressure is 30 - 250 Torr in the first tower for distillation of water and acetic acid and the operating pressure is in the range 2 - 100 Torr in the second tower for separation of high boiling point materials.
4. A method according to claim 1, wherein a series of at least three distillation towers are employed, distillation of water and acetic acid being effected in a first tower, separation of isomers of diacetoxybutenes being effected in a second tower, and separation of high boiling point materials being effected in a third tower, the temperatures of the bottom of each tower being maintained lower than 190°C.
5. A method according to claim 4, wherein the temper-ature of the bottom of each tower is in a range of 190 - 120°C, and the operating pressure is from 30 - 250 Torr in the first tower for distillation of water and acetic acid, the operating pressure is from 10 - 230 Torr in the second tower for separation of isomers of diacetoxybutene and the operating pressure is from 2 - 100 Torr in the third tower for separation of high boiling point materials.
6. A fractional distillation method of separating diacetoxybutene isomers from a reaction mixture, produced from the reaction of butadiene, acetic acid and molecular oxygen which comprises employing a series of two distillation towers, feeding said reaction mixture into the first tower to distill away water and acetic acid under a pressure of 30 - 250 Torr and a tower bottom temperature within the range of from 120°C to less than 190°C, withdrawing the material remaining in the bottom of the first tower and then feeding said material into the second tower to separate diacetoxybutene from high boiling point materials under a pressure of 2 - 100 Torr and a tower bottom temperature within the range of from 120°C to less than 190°C.
7. The method of claim 6, wherein the pressure of the first tower is 30 - 150 Torr and that of the second is 5 - 50 Torr.
8. The method of claim 6, wherein the bottom temperature of both towers is from 140° to 180°C.
9. The method of claim 6, wherein the reaction mixture has been degassed prior to distillation.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP49028413A JPS5827258B2 (en) | 1974-03-12 | 1974-03-12 | Diacetoxybutene |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1047964A true CA1047964A (en) | 1979-02-06 |
Family
ID=12247957
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA221,902A Expired CA1047964A (en) | 1974-03-12 | 1975-03-12 | Method of separating diacetoxybutene |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS5827258B2 (en) |
| BE (1) | BE826476A (en) |
| CA (1) | CA1047964A (en) |
| DE (1) | DE2510088C2 (en) |
| FR (1) | FR2264000B1 (en) |
| GB (1) | GB1445076A (en) |
| IT (1) | IT1034152B (en) |
| NL (1) | NL7502573A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5374830B2 (en) * | 2006-05-10 | 2013-12-25 | 三菱化学株式会社 | Isomerization method of diacetoxyallyl compound |
-
1974
- 1974-03-12 JP JP49028413A patent/JPS5827258B2/en not_active Expired
-
1975
- 1975-03-05 NL NL7502573A patent/NL7502573A/en active Search and Examination
- 1975-03-07 DE DE19752510088 patent/DE2510088C2/en not_active Expired
- 1975-03-10 BE BE154167A patent/BE826476A/en not_active IP Right Cessation
- 1975-03-11 GB GB1007775A patent/GB1445076A/en not_active Expired
- 1975-03-11 FR FR7507537A patent/FR2264000B1/fr not_active Expired
- 1975-03-12 CA CA221,902A patent/CA1047964A/en not_active Expired
- 1975-03-28 IT IT2111275A patent/IT1034152B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| DE2510088C2 (en) | 1985-07-04 |
| FR2264000B1 (en) | 1980-01-25 |
| IT1034152B (en) | 1979-09-10 |
| JPS50121210A (en) | 1975-09-23 |
| GB1445076A (en) | 1976-08-04 |
| JPS5827258B2 (en) | 1983-06-08 |
| NL7502573A (en) | 1975-09-16 |
| DE2510088A1 (en) | 1975-09-18 |
| FR2264000A1 (en) | 1975-10-10 |
| BE826476A (en) | 1975-09-10 |
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