JP2003026622A - Method for producing 1,4-butanediol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for stably carrying out a hydrogenation purification of a crude 1,4-butanediol obtained by distilling hydrolyzed solution and reacting butadiene with acetic acid and oxygen in the presence of a catalyst to produce a reaction product containing 1,4-diacetoxybutene, hydrogenating the reaction product, and hydrolyzing the hydrogenated product. SOLUTION: The crude 1,4-butanediol having <=0.5 wt.% concentration of 2-(4'-hydroxybutoxy)tetrahydrofuran based on the amount of the 1,4-butanediol is extracted from a lower part of a distillation column of a hydrolyzed liquid as a side stream, and the extracted crude 1,4-butanediol is subjected to the hydrogenation reaction.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to the reaction of butadiene, acetic acid and oxygen to produce 1,4-diacetoxybutene, which is hydrogenated to give 1,4-diacetoxybutane and then hydrolyzed. The present invention relates to an improved method for producing 1,4-butanediol.

[0002]

2. Description of the Related Art There are several known methods for producing 1,4-butanediol. One of the typical methods is to react 1,4-butanediol with butadiene, acetic acid and oxygen in the presence of a catalyst.
There is a method of producing 4-diacetoxybutene, hydrogenating this to 1,4-diacetoxybutane, and then hydrolyzing it to produce 1,4-butanediol.
It is carried out industrially. In this method, in the step of producing 1,4-diacetoxybutene and the hydrolysis step,
Various by-products are produced. Therefore, the hydrolysis reaction product liquid contains various components in addition to 1,4-butanediol. The main ones are water, acetic acid, 1,4- and 1,
2-diacetoxybutane, 1-hydroxy-4-acetoxybutane, 1,2-butanediol monoacetate, 1,2-butanediol and the like, and some components having a higher boiling point than 1,4-butanediol are also contained. ing.

While 1,4-butanediol has a variety of uses, one of its major uses is in the production of polybutylene terephthalate. And for this purpose,
4-butanediol is required. Several methods have been proposed for obtaining highly pure 1,4-butanediol from the above-mentioned hydrolysis reaction product liquid. In a typical method thereof, the hydrolysis reaction product liquid is distilled to obtain a light boiling point component. And high-boiling components are removed to obtain crude 1,4-butanediol, which is hydrogenated to give 2- (4′-hydroxybutoxy) tetrahydrofuran, 2- (4) which is a main impurity contained. ′ -Oxobutoxy) tetrahydrofuran, 1,4-bis (2′-tetrahydrofuroxy) butane, etc. are converted to tetrahydrofuran or 1,4-butanediol and then distilled again to obtain highly pure 1,4
-Obtain butanediol (JP-A-61-19753)
(See Japanese Patent Publication No. 4).

[0004]

Since the hydrolysis reaction product solution contains various components as described above, crude 1,4-butanediol which gives high-purity 1,4-butanediol by hydrogenation and distillation is obtained. In order to obtain 4-butanediol, these components must be sufficiently removed from the hydrolysis reaction product liquid. In the typical method, the hydrolysis reaction liquid is first distilled in the first distillation column to distill acetic acid and water from the top, and from the bottom of the column, butane consisting of 1,2- and 1,4-butanediol. Diols, 1,2- and 1,4
-Diacetoxybutanes consisting of diacetoxybutane,
A bottoms liquid containing hydroxyacetoxybutanes composed of 1,2- and 1,4-butanediol monoacetate, and a heavy component is obtained. Next, this bottom liquid is distilled in a second distillation column to distill 1,2-butanediol from the top of the column, and diacetoxybutanes and hydroxyacetoxybutanes are made into a side stream (upper side stream) from the top of the column. The crude 1,4-butanediol is withdrawn as a side stream (lower side stream) from the lower part of the tower, and the heavy component is withdrawn from the bottom of the tower. For extracting crude 1,4-butanediol as a sidestream, a liquid phase extraction method and a gas phase extraction method can be considered. However, when the crude 1,4-butanediol is extracted in the liquid phase, catalyst removal in the subsequent hydrogenation step may occur. It is said that it is preferable to extract it in the gas phase because it is highly poisonous (see JP-A-6-172235). However, the vapor phase extraction method has a drawback that the energy consumption of the distillation column is large because 1,4-butanediol is extracted in a high energy state having latent heat of vaporization. Accordingly, the present invention seeks to provide a method for withdrawing crude 1,4-butanediol as a lower sidestream in the liquid phase and yet avoiding severe catalyst poisoning in the subsequent hydrogenation step.

[0005]

According to the present invention, butadiene, acetic acid and oxygen are reacted in the presence of a catalyst to give 1,4
A method for producing 1,4-butanediol in which a reaction product containing diacetoxybutene is produced, the reaction product is hydrogenated to saturate the carbon-carbon double bond, and then hydrolyzed; Is distilled to remove light-boiling components and high-boiling components to obtain crude 1,4-butanediol, which is hydrogenated in the presence of a catalyst to reduce impurities. 2- (4'-hydroxybutoxy) calculated by the formula (1)
The crude 1,4-butanediol having a tetrahydrofuran concentration of 0.5% by weight or less relative to 1,4-butanediol is withdrawn from the lower part of the distillation column as a side stream in a liquid phase and subjected to a hydrogenation reaction to produce hydrogen. The addition reaction can be stably performed over a long period of time, and 1,4-butanediol can be produced with energy efficiency.

[0006]

[Equation 2]

In the formula, W: the amount of 1,4-butanediol in the crude 1,4-butanediol sample used for analysis (g) S: The sample was reacted with a 5% hydroxylamine hydrochloride-ethanol solution in ethanol. , 0.1N alcoholic caustic potash solution titration amount (ml) B: alcoholic caustic potash solution consumption amount in blank test (ml) f: alcoholic caustic potash solution factor

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a reaction product containing 1,4-diacetoxybutene from butadiene, acetic acid and oxygen is produced, and the obtained reaction product is hydrogenated to saturate the carbon-carbon double bond. Basically, any of the reaction to cause and the hydrolysis reaction of the hydrogenation reaction product can be carried out according to a known method. The production of the reaction product containing 1,4-diacetoxybutene is carried out by continuously supplying butadiene and acetic acid in a liquid phase, usually by dissolving butadiene in acetic acid, into a reactor containing a catalyst-packed bed. At the same time, it can be carried out by continuously supplying an oxygen-containing gas such as air to the reactor. Since acetic acid is used also as a reaction solvent, the ratio of acetic acid to butadiene supplied to the reactor is usually 5 to 60 times the stoichiometric amount, preferably 10 to 10.
It is 40 times. Oxygen is also preferably used in a large excess so long as the gas phase in the reactor does not have an explosive composition.

The reaction temperature is 40 to 120 ° C., preferably 50 to 80 ° C., and the pressure is usually normal pressure or slightly reduced pressure. As the catalyst, a carrier-supported catalyst in which a carrier selected from the group consisting of precious metals and tellurium, antimony, arsenic and selenium is used. It is preferable to use silica or activated carbon as the carrier. Most preferred is a catalyst in which palladium and tellurium are supported on silica. With this catalyst, 2- (4'-hydroxybutoxy) calculated from hydroxylamine consumption is obtained by the subsequent distillation of the hydrolysis reaction product solution. ) The concentration of tetrahydrofuran is 0.5 with respect to 1,4-butanediol.
It is easy to obtain less than 1% by weight of crude 1,4-butanediol. That is, the by-products that are produced differ slightly depending on the carrier that constitutes the catalyst and the noble metal, and for the catalyst that uses silica as the carrier, the by-product of 2- (4'-hydroxybutoxy) tetrahydrofuran calculated from hydroxylamine consumption is compared. Few. The palladium content of the silica-supported palladium-tellurium catalyst is preferably 0.1 to 20% by weight, particularly preferably 0.5 to 10% by weight, and tellurium has an atomic ratio of 0.05 to 5 times, particularly preferably 0. 15 ~
It is preferably 0.35 times.

The reaction product liquid obtained by the reaction of butadiene, acetic acid and oxygen is gas-liquid separated and then distilled to remove acetic acid and high-boiling components to obtain a fraction mainly consisting of diacetoxybutene. Is hydrogenated to saturate the carbon-carbon double bond and convert diacetoxybutene to diacetoxybutane. In this hydrogenation reaction, a diacetoxybutene fraction and hydrogen are continuously supplied to a reactor containing a packed bed of a carrier-supported precious metal catalyst, for example, a catalyst in which activated carbon carries a precious metal, preferably palladium. It is done by doing. The reaction temperature is preferably 20 to 180 ° C, particularly preferably 30 to 150 ° C, and the pressure is preferably normal pressure or increased pressure.

In a preferred embodiment of the present invention, hydrogenation is carried out using the above-mentioned activated carbon-supported noble metal catalyst, and then hydrogenation is carried out using a catalyst in which a noble metal, preferably ruthenium is supported on silica. The hydrogenation reaction using this silica-supported catalyst may be carried out under the same reaction conditions as the hydrogenation reaction using the above-mentioned activated carbon-supported catalyst, but the reaction temperature is slightly higher, for example, preferably 30 to 100 ° C. higher.
When the hydrogenation reaction is carried out in two stages using the activated carbon-supported catalyst and the silica-supported catalyst in this way, it is calculated based on the hydroxylamine consumption amount by the subsequent distillation of the hydrolysis reaction product liquid. It is easy to obtain crude 1,4-butanediol having a concentration of hydroxybutoxy) tetrahydrofuran of 0.5% by weight or less. It is considered that the hydrogenation reaction using the silica-supported catalyst in the latter stage reduces the impurities or precursors thereof that react with hydroxylamine in the diacetoxybutene fraction subjected to the hydrogenation reaction.

The diacetoxybutane obtained by the hydrogenation reaction is then hydrolyzed to convert the diacetoxybutane into butanediol. This hydrolysis reaction is usually carried out by continuously supplying a mixed solution of diacetoxybutane and water to a reactor containing a packed bed of a strongly acidic cation exchange resin. The content of water in the mixed solution is 2 to 100 times the theoretical amount required to completely carry out the hydrolysis,
It is particularly preferably 4 to 50 times. The hydrolysis temperature is 30 ~
110 degreeC, especially 40-90 degreeC are preferable. In addition to butanediols, hydrolysis also produces an intermediate, hydroxyacetoxybutanes. The production ratio of butanediols and hydroxyacetoxybutanes greatly depends on the conditions of the hydrolysis reaction. In addition, since 1-hydroxy-4-acetoxybutane can be dehydrocyclized to give tetrahydrofuran, when 1,4-butanediol and tetrahydrofuran are co-produced, the hydrolysis conditions should be adjusted so as to match the co-production ratio. To set.

The hydrolysis reaction product liquid is distilled to remove light-boiling components and high-boiling components to obtain crude 1,4-butanediol, which is subjected to the subsequent hydrogenation reaction. In the present invention, the concentration of 2- (4′-hydroxybutoxy) tetrahydrofuran calculated based on the formula (1) is 0.5% by weight.
The following crude 1,4-butanediol is withdrawn in the liquid phase as a side stream from the lower part of the distillation column and subjected to the hydrogenation reaction. Usually, the hydrolysis reaction liquid is first distilled in the first distillation column to distill acetic acid and water from the top and 1,2- and 1,4 from the bottom.
-Butanediols consisting of butanediol, 1,2-
And a bottoms solution consisting of diacetoxybutanes consisting of 1,4-diacetoxybutane and hydroxyacetoxybutanes consisting of 1,2- and 1,4-butanediol monoacetate. The bottom liquid also contains a heavy component having a boiling point higher than that of 1,4-butanediol.
As the first distillation column, one having a theoretical plate number of 2 to 10 is used.
It is preferable to operate at a column top pressure of 5 to 100 kPa, particularly 7 to 30 kPa, and a column bottom temperature of 100 to 200 ° C, particularly 120 to 180 ° C.

The bottom liquid of the first distillation column is fed to the second distillation column for further distillation, and is calculated based on the formula (1) 2- (4 '
-Hydroxybutoxy) tetrahydrofuran concentration is 0.
5% by weight or less of crude 1,4-butanediol is withdrawn in the liquid phase as a side stream from the lower part of the column. 1,2-Butanediol, which has a lower boiling point than 1,4-butanediol, diacetoxybutanes and hydroxyacetoxybutanes can be distilled from the top of the column, but normally 1,2-butanediol is the top of the column. The diacetoxybutanes and the hydroxyacetoxybutanes are withdrawn as a side stream from the upper part of the column and used for each purpose. This second distillation column uses a theoretical plate number of 60 to 120 plates, particularly 80 to 100 plates, and a column top pressure of 5 to 100 kPa, particularly 7 to 60 kPa,
It is preferable to operate at a bottom temperature of 130 to 270 ° C, particularly 150 to 250 ° C. The crude 1,4-butanediol withdrawn in the liquid phase as a side stream from the lower part of the second distillation column has a 2- (4'-hydroxybutoxy) tetrahydrofuran concentration of 1, calculated based on the formula (1). It should be 0.5% by weight or less based on 4-butanediol. For that purpose, as described above, selection of a catalyst for producing a reaction product containing diacetoxybutene from butadiene, acetic acid, and oxygen, and hydrogenation of diacetoxybutene, di-saturated carbon-carbon double bond. It is preferable to reduce the amount of impurities or precursors thereof that react with hydroxylamine by selecting a hydrogenation catalyst when converting to acetoxybutane. In addition, by adjusting the withdrawal position of the lower side stream of the second distillation column and the operating conditions of the distillation column,
It is also possible to reduce their amount in the crude 1,4-butanediol withdrawn in the liquid phase as a sidestream.

The crude 1,4-butanediol withdrawn as a sidestream is hydrogenated in the presence of a catalyst. In this hydrogenation reaction, 2- (4'-hydroxybutoxy) tetrahydrofuran, 2- (4'-oxobutoxy) tetrahydrofuran, and 1,4-bis (2), which are the main impurities in the crude 1,4-butanediol, are used. ′ -Tetrahydrofuroxy)
Butane and the like are hydrolyzed to give tetrahydrofuran and 1,
Converted to 4-butanediol. Any conventional catalyst may be used as the catalyst, but it is usually preferable to use a palladium catalyst with a carrier such as an activated carbon-supported palladium catalyst. The reaction conditions for hydrogenation are 40 to 250 ° C., preferably 80 to 180 ° C., and pressure is normal pressure or increased pressure.
Particularly, 0.4 to 2 MPa (gauge pressure) is preferable. In addition,
The hydrogenation reaction can be carried out using hydrogen diluted with an inert gas, in addition to pure hydrogen.

From the hydrogenation reaction product liquid, 1,4-butanediol purified to a high purity can be obtained by removing the light-boiling components and the high-boiling components by distillation according to a conventional method.

[0017]

EXAMPLES The present invention will be described in more detail with reference to the following examples. The consumption of hydroxylamine is measured as follows. Preparation of reagent for measuring consumption of hydroxylamine: Hydroxylamine hydrochloride (special grade) 50
g is dissolved in 100 g of water. Hydrochloric acid (special grade reagent)
After adding 8.5 ml, the total volume is adjusted to 1 liter with ethyl alcohol (special grade reagent).

Analytical operation; calculated by the formula (1)
According to the approximate concentration of (4'-hydroxybutoxy) tetrahydrofuran, a sample having the following weight is collected in a 100 ml Erlenmeyer flask. Accurately add 10 ml of the above-prepared reagent to the Erlenmeyer flask using a whole pipette.

After immersing the Erlenmeyer flask in a hot water bath at 60 ± 2 ° C. for 2 hours, the content liquid was thoroughly washed with methanol and transferred to a 100 ml beaker.
Set to ml. The solution in the beaker is titrated with 0.1N methyl alcohol potassium hydroxide (special grade reagent). Example 1 In the presence of a catalyst obtained by supporting palladium and tellurium on silica, air diluted with butadiene, acetic acid and nitrogen was added to
The reaction was carried out at 70 to 85 ° C. at MPa (gauge pressure) to obtain a solution containing diacetoxybutene. The solution was distilled to remove acetic acid and high boilers, and a fraction mainly consisting of diacetoxybutene was obtained. In the presence of a catalyst in which palladium is supported on activated carbon, the fraction obtained above is treated with 5M.
Hydrogen (Pa (gauge pressure), 40-70 ° C, carbon-
Hydrogenation of the carbon double bond was performed. In the presence of a catalyst in which ruthenium was supported on silica, the hydrogenation reaction product liquid obtained above was further hydrogenated at 5 MPa (gauge pressure) and 70 to 100 ° C.

The hydrogenation reaction product liquid is then DIAION SKIB which is a sulfonic acid type strongly acidic cation exchange resin.
(Mitsubishi Chemical Corporation product, Diaion is a registered trademark of the same company) was hydrolyzed at 40 to 60 ° C. The hydrolysis reaction product liquid was distilled to distill water and acetic acid from the top of the tower, and a bottom liquid of the following composition was obtained from the bottom of the tower. Composition of bottom liquid (% by weight) 1,4-butanediol 42.1 1,2-butanediol 7.1 1,4-diacetoxybutane 9.2 1,2-diacetoxybutane 0.3 1,4 -Butanediol monoacetate 39.0 1,2-butanediol monoacetate 1.9 The concentration of 2- (4'-hydroxybutoxy) tetrahydrofuran calculated based on the consumption of hydroxylamine in the bottom liquid of the column is 0. It was 0.2% by weight.

Using a packed column with 96 theoretical plates, 21K
The bottom liquid obtained above was distilled at Pa, a bottom temperature of 195 ° C., and a reflux ratio of 30. The upper side stream was extracted from the position of the 25th stage from the top of the column, and the lower side stream was extracted from the position of the 98th stage from the top of the column in the liquid phase. The weight composition of each fraction obtained from the distillation column was as follows. Top distillate: 1,2-butanediol 74%, 1,2-
Butanediol monoacetate 20%, 1,2-diacetoxybutane 4% Upper side stream: 1,4-butanediol monoacetate 6
4%, 1,4-butanediol 19%, 1,4-diacetoxybutane 15% Lower sidestream: 1,4-butanediol 99.4%, 2-
(4'-Hydroxybutoxy) tetrahydrofuran
4%, high-boiling point substance 0.1%, bottom liquid: 1,4-butanediol 95%, high-boiling point substance In a reactor filled with a catalyst in which activated carbon is loaded with palladium at 1% by weight, The lower side stream obtained above was passed with hydrogen to carry out a hydrogenation reaction. The reaction is
0.9 MPa (gauge pressure), 100 ° C., hydrogen / side flow =
0.00027 (weight ratio), side space liquid space velocity 1.5h
^Performed at r ^-1 .

After the reaction product liquid is separated into gas and liquid, a packed column having 40 theoretical plates is used, and the pressure is 6.7 KPa and the bottom temperature is 1
It was distilled at 63 ° C. and a reflux ratio of 50. The reaction product liquid was supplied to the 29th plate from the top of the column, and 1,4-butanediol purified to a high purity was withdrawn as a side stream from the position of the 20th plate from the column top. The purity of 1,4-butanediol was 99.8%, and the concentration of 2- (4′-hydroxybutoxy) tetrahydrofuran calculated based on the consumption of hydroxylamine in 1,4-butanediol was 100% after the start of operation. 0.09% by weight at hour, 0.11% by weight at 1000 hours
Met. Comparative Example 1 In Example 1, as a catalyst when butadiene, acetic acid and oxygen are reacted to produce diacetoxybutene,
Other than using a catalyst in which palladium and tellurium are supported on activated carbon, and a catalyst in which ruthenium is supported on activated carbon is used as a hydrogenation catalyst in the latter stage after hydrogenating a carbon-carbon double bond of a diacetoxybutene fraction. In the same manner as in Example 1, 1,4-butanediol was produced.

2-calculated based on the amount of hydroxylamine consumed in the bottom liquid of the distillation column of the hydrolysis reaction product liquid
The (4'-hydroxybutoxy) tetrahydrofuran concentration was 1.0% by weight. Further, the concentration of 2- (4'-hydroxybutoxy) tetrahydrofuran in the lower side stream of the distillation column of the bottom liquid was 1.9% by weight. The purity of 1,4-butanediol obtained by hydrogenating this side stream and then distilling was 99.4% by weight 100 hours after the start of operation and 98.5% by weight after 1000 hours. 4-
2- (4'-hydroxybutoxy) in butanediol
Tetrahydrofuran concentration was 0.21% by weight 100 hours after the start of operation and 1.07% by weight after 1000 hours, and the deterioration of the catalyst over time during hydrogenation of the sidestream was large.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C07C 69/16 C07C 69/16 // C07B 61/00 300 C07B 61/00 300 (72) Inventor Seijiro Nishimura 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Chemical Co., Ltd. F-term in Yokkaichi Operations (Reference) 4H006 AA02 AC41 AC48 AD11 AD31 BA15 BA25 BA55 BA60 BA61 BE20 BE30 BN00 FE11 FG28 KA12 KA30 KD00 4H039 CA19 CA29 CA66 CB10 CC10

Claims (8)

[Claims] 1. A reaction product comprising 1,4-diacetoxybutene is produced by reacting butadiene, acetic acid and oxygen in the presence of a catalyst, and the reaction product is hydrogenated to form a carbon-carbon double bond. In a method for producing 1,4-butanediol which is saturated and then hydrolyzed, a hydrolysis reaction product liquid is distilled to remove light-boiling components and high-boiling components to obtain crude 1,4-butanediol.
The concentration of 2- (4'-hydroxybutoxy) tetrahydrofuran calculated by the formula (1) based on the consumption of hydroxylamine in obtaining butanediol and hydrogenating it in the presence of a catalyst to reduce impurities But 1,4
A method comprising extracting crude 1,4-butanediol in an amount of 0.5% by weight or less with respect to butanediol in a liquid phase as a sidestream from the lower part of the distillation column and using it for the hydrogenation reaction. [Equation 1] In the formula, W: the amount of 1,4-butanediol in the crude 1,4-butanediol sample used for analysis (g) S: After reacting the sample with 5% hydroxylamine hydrochloride-hydrochloric acid / ethanol solution, 0 .1 consumption of alcoholic caustic potash solution when titrated with 1N alcoholic caustic potash solution (ml) B: consumption amount of alcoholic caustic potash solution in blank test (ml) f: factor of alcoholic caustic potash solution 2. A catalyst in which a carrier is loaded with a noble metal and one selected from the group consisting of tellurium, antimony, arsenic and selenium in the reaction of reacting butadiene, acetic acid and oxygen to produce 1,4-diacetoxybutene. The method according to claim 1, which is carried out in the presence of 3. The reaction of reacting butadiene, acetic acid and oxygen to produce 1,4-diacetoxybutene is carried out in the presence of a catalyst in which palladium and tellurium are supported on silica. the method of. 4. The hydrogenation of the reaction product containing 1,4-diacetoxybutene is carried out in two stages, a first stage reaction using an activated carbon-supported noble metal catalyst and a second stage reaction using a silica-supported noble metal catalyst. The method according to any one of claims 1 to 3. 5. The hydrogenation of a reaction product containing 1,4-diacetoxybutene is carried out by a first-step reaction using a catalyst having palladium supported on activated carbon and a second-step reaction using a catalyst having ruthenium supported on silica. 4. The method according to claim 1, wherein the method is performed in stages. 6. The method according to claim 1, wherein the crude 1,4-butanediol is hydrogenated in the presence of a catalyst in which a noble metal is supported on activated carbon or silica. 7. A highly purified 1,4-butanediol is obtained by distilling a hydrogenation reaction product liquid obtained by hydrogenating crude 1,4-butanediol. 7. The method according to any one of 1 to 6. 8. A column bottom containing butanediols, diacetoxybutanes and hydroxyacetoxybutanes is distilled from the top of the column by distilling the hydrolysis reaction product liquid in the first distillation column to distill water and acetic acid from the column top. A liquid was obtained, and this was distilled in a second distillation column to distill 1,2-butanediol from the top of the column, diacetoxybutanes and hydroxyacetoxybutanes were withdrawn as an upper side stream, and crude as a lower side stream. 1,
The method according to claim 1, wherein 4-butanediol is withdrawn in a liquid phase.