WO2013005747A1

WO2013005747A1 - 1,4-butanediol-containing composition

Info

Publication number: WO2013005747A1
Application number: PCT/JP2012/067009
Authority: WO
Inventors: 雄輔井澤; 宇都宮　賢; 範和小西; 真一郎松園; 鈴木　隆行
Original assignee: 三菱化学株式会社
Priority date: 2011-07-04
Filing date: 2012-07-03
Publication date: 2013-01-10
Also published as: JP2013049666A

Abstract

The objective of the present invention is to provide a 1,4-butanediol-containing composition that, compared to conventional 1,4-butanediol, has a high thermal stability and is optimal as the starting material for a derivative of 1,4-butanediol. The present invention pertains to a 1,4-butanediol-containing composition wherein the concentration of 1,4-butanediol is 99.00-99.99 wt%, and the concentration in terms of nitrogen atoms of a nitrogen-containing compound represented by formula (1) is 1.0-50 wt ppm.

Description

1,4-butanediol-containing composition

The present invention relates to a composition containing 1,4-butanediol.

1,4-butanediol (hereinafter sometimes abbreviated as “1,4BG”) is known to be an extremely useful substance used as a raw material for various solvents and derivatives. Conventionally, various methods for industrially producing 1,4BG have been developed. For example, diacetoxy, which is an intermediate obtained by performing an acetoxylation reaction using butadiene as a raw material and raw materials butadiene, acetic acid and oxygen. A method of producing 1,4BG by hydrogenating and hydrolyzing the diacetoxybutene (Patent Document 1), using maleic acid, succinic acid, maleic anhydride and / or fumaric acid as raw materials, A crude hydrogenated product containing 1,4BG by hydrogenation (Patent Document 2), a method for producing 1,4BG by hydrogenating butynediol obtained by contacting acetylene with a formaldehyde aqueous solution (Patent Document 2) Reference 3).

Tetrahydrofuran (hereinafter sometimes abbreviated as “THF”), which is a derivative derived from 1,4BG, is generally used as a solvent, but is a polyether polyol (specifically, polytetramethylene ether). Glycol). As a method for producing THF from 1,4BG, Patent Document 4 discloses a method in which THF is continuously produced by reaction of a reaction mixture containing 1,4BG over a heteropolyacid catalyst. It is described that the life of the heteropolyacid catalyst can be extended by containing (4-hydroxybutoxy) -tetrahydrofuran and a basic nitrogen component of less than 1 ppm. Polybutylene terephthalate (hereinafter sometimes abbreviated as “PBT”) is another derivative using 1,4BG as a raw material. However, Patent Document 5 discloses that 1,4BG as a raw material is a secondary component in an ester reaction. A method for producing PBT by controlling the reaction conditions (catalyst raw material concentration, reaction pressure, ratio of terephthalic acid and 1,4BG, etc.) is described so that 1,4BG is not wasted as raw THF.

Japanese Laid-Open Patent Publication No. 52-7909 Japanese Patent No. 2930141 Japanese Patent Publication No. Sho 62-4174 Japan Special Table 2006-503050 Japanese Unexamined Patent Publication No. 2005-350659

The 1,4BG obtained by the methods described in Patent Documents 1 to 3 is a crude 1,4BG having a low purity containing impurities generated from unreacted raw materials and by-products and catalysts used in the production process. Therefore, in order to use it as a raw material for the derivatives described in Patent Document 4 and Patent Document 5, usually, purification such as distillation is performed so that the specifications meet the purpose of using 1,4BG, and the quality is improved. Use good 1,4BG.

However, when the refined high-quality 1,4BG is actually applied to its use, the quality is poor compared to the immediately-purified 1,4BG, in particular, 1,4BG is used as a raw material for PBT. It was found that the thermal stability of 1,4BG deteriorates (THF is generated in 1,4BG).
The present invention has been made in view of the above problems, and an object of the present invention is to provide a 1,4-butanediol-containing composition having higher thermal stability than conventional 1,4BG.

As a result of intensive studies to solve the above problems, the present inventors have found that a small amount of acid content that cannot be removed by conventional purification is present in 1,4BG obtained by purification, and this acts as an acid catalyst. Therefore, under the assumption that some 1,4BG is converted to THF, surprisingly, among the nitrogen-containing compounds conventionally considered to be a cause of catalyst deterioration, a compound having a skeleton having a specific structure Is mixed in a specific concentration range, the catalyst deterioration can be suppressed, and further conversion of 1,4BG to THF can be suppressed, and as a result, the thermal stability can be greatly improved. It came to complete.

The present invention has been achieved on the basis of such findings, and the following [1] to [3] are summarized.
[1] The concentration of 1,4-butanediol is 99.00 wt% or more and 99.99 wt% or less, and the concentration of the nitrogen-containing compound represented by the following formula (1) in terms of nitrogen atom is 1. 1,4-butanediol-containing composition that is 0 to 50 ppm by weight.

(In the above formula (1), R ¹ to R ³ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, an alkoxy group, a hydroxy group, an amino group, an alkylthio group, or an arylthio group. The group may further have a substituent, and the substituent may contain a hetero atom, and R ¹ and R ² , R ² and R ³ , R ³ and R ¹ are Each may be linked to each other to form a ring, except that R ¹ to R ³ are all hydrogen atoms.)
[2] The 1,4-butanediol-containing composition according to [1], wherein the pH is 7.01 or more and 10.5 or less.
[3] A method for producing a polyester by polycondensation reaction of 1,4-butanediol with at least one of dicarboxylic acid and dicarboxylic acid ester, wherein the concentration of 1,4-butanediol as a raw material is 99.00. 1,4-butanediol-containing composition having a concentration of 1.0 to 50 ppm by weight in terms of nitrogen atom of the nitrogen-containing compound represented by the following formula (1): The manufacturing method of polyester using a thing.

(In the above formula (1), R ¹ to R ³ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, an alkoxy group, a hydroxy group, an amino group, an alkylthio group, or an arylthio group. The group may further have a substituent, and the substituent may contain a hetero atom, and R ¹ and R ² , R ² and R ³ , R ³ and R ¹ are Each may be linked to each other to form a ring, except that R ¹ to R ³ are all hydrogen atoms.)

The 1,4-butanediol-containing composition of the present invention has high thermal stability, and even when used as a raw material for derivatives, coloring and catalyst poisoning in subsequent steps can be suppressed.

Hereinafter, the present invention will be described in more detail.
1,4BG contained in the 1,4-butanediol-containing composition of the present invention can be obtained by a conventionally known production method. For example, an acetoxylation reaction is performed using raw material butadiene, acetic acid and oxygen to obtain diacetoxybutene as an intermediate, and hydrogenation and hydrolysis of the diacetoxybutene, 1,4BG, maleic acid, 1,4BG obtained by hydrogenating succinic acid, maleic anhydride and / or fumaric acid as raw materials, crude 1,4BG obtained by hydrogenating butynediol obtained by contacting acetylene with a formaldehyde aqueous solution 1,4BG obtained through oxidation of propylene, 1,4BG obtained by hydrogenating succinic acid obtained by fermentation, 1,4BG obtained by direct fermentation from biomass such as sugar, and the like.

The concentration of 1,4BG in the 1,4-butanediol-containing composition of the present invention is 99.00 wt% or more and 99.99 wt% or less, preferably 99.20 wt% or more and 99.97 wt%. % Or less, more preferably 99.50% by weight or more and 99.95% by weight or less. The higher the 1,4BG concentration, the higher the purification cost, and the lower the concentration, the more likely it is that by-products are produced during the production of the polyester, etc.

The 1,4-butanediol-containing composition of the present invention needs to contain a nitrogen-containing compound represented by the following formula (1).

In the formula (1), R ¹ to R ³ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, an alkoxy group, a hydroxy group, an amino group, an alkylthio group or an arylthio group. This group may further have a substituent, and the substituent may contain a hetero atom. R ¹ to R ³ may be the same or different, except when R ¹ to R ³ are all hydrogen atoms.

R ¹ to R ³ are preferably each independently a hydrogen atom, an alkyl group, an aryl group, or an amino group from the viewpoint of suppressing deterioration of the catalyst and improving basicity. In this case, R ¹ to R ³ may be the same or different, except when R ¹ to R ³ are all hydrogen atoms.

The alkyl group is a chain (linear or branched) alkyl group or a cyclic alkyl group. In the case of a chain alkyl group, the alkyl group usually has 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. Specific examples thereof include, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, An octyl group, a decyl group, etc. are mentioned. In the case of a cyclic alkyl group, it usually has 3 to 20 carbon atoms, preferably 4 to 11 carbon atoms. Specific examples thereof include a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. The substituent that the alkyl group may have is not particularly limited as long as it does not significantly impair the effects of the present invention. For example, an aryl group, an acyl group, a hydroxy group, an alkoxy group, an aryloxy group, an alkyl group An aryloxy group, an amino group, an aminoalkyl group, a sulfide group and the like can be mentioned, and those having a molecular weight of about 200 or less are usually used. Moreover, in this substituent, hetero atoms, such as oxygen, nitrogen, sulfur, and phosphorus, may be contained.

The alkenyl group is a chain (straight chain or branched) alkenyl group or a cyclic alkenyl group, and in the case of a chain alkenyl group, it usually has 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. Specific examples include ethenyl group, 1-propenyl group, isopropenyl group, 2-butenyl group, 1,3-butadienyl group, 2-pentenyl group, 2-hexenyl group and the like. In the case of a cyclic alkyl group, it usually has 3 to 20 carbon atoms, preferably 4 to 11 carbon atoms. Specific examples thereof include a cyclopropenyl group, a cyclopentenyl group, and a cyclohexenyl group. The substituent that the alkenyl group may have is not particularly limited as long as it does not significantly impair the effects of the present invention. For example, an aryl group, an acyl group, a hydroxy group, an alkoxy group, an aryloxy group, an alkyl group An aryloxy group, an amino group, an aminoalkyl group, a sulfide group and the like can be mentioned, and those having a molecular weight of about 200 or less are usually used. Moreover, in this substituent, hetero atoms, such as oxygen, nitrogen, sulfur, and phosphorus, may be contained.

As the aryl group, phenyl group, benzyl group, mesityl group, naphthyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2,3-dimethylphenyl group, 2,4-dimethylphenyl group 2,5-dimethylphenyl group, 2,6-dimethylphenyl group, 2-ethylphenyl group, isoxazolyl group, isothiazolyl group, imidazolyl group, oxazolyl group, thiazolyl group, thiadiazolyl group, thienyl group, thiophenyl group, triazolyl group, Tetrazolyl group, pyridyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, pyrazolyl group, pyrrolyl group, pyranyl group, furyl group, furazanyl group, imidazolidinyl group, isoquinolyl group, isoindolyl group, indolyl group, quinolyl group, pyridothiazolyl group, benzimidazo Re Group, benzoxazolyl group, benzothiazolyl group, benzotriazolyl group, benzofuranyl group, imidazopyridinyl group, triazopyridinyl group, purinyl group and the like, usually having 5 to 20 carbon atoms, Preferably it is 5 to 12, and includes a heteroaryl group containing oxygen, nitrogen, sulfur and the like. The substituent that the aryl group may have is not particularly limited as long as it does not significantly impair the effects of the present invention, and includes an alkyl group having 1 to 10 carbon atoms, an acyl group having 1 to 10 carbon atoms, An alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an alkylaryl group having 7 to 12 carbon atoms, a carbon number of 7 -12 alkylaryloxy group, arylalkyl group having 7-12 carbon atoms, arylalkoxy group having 7-12 carbon atoms, hydroxy group, and the like. Further, this substituent may further contain a heteroatom such as oxygen, nitrogen, sulfur, phosphorus and halogen.

Specific examples include phenyl group, benzyl group, mesityl group, naphthyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2,3-dimethylphenyl group, 2,4-dimethylphenyl group. 2,5-dimethylphenyl group, 2,6-dimethylphenyl group, 2-ethylphenyl group, 2-isopropylphenyl group, 2-t-butylphenyl group, 2,4-di-t-butylphenyl group, 2 -Chlorophenyl group, 3-chlorophenyl group, 4-chlorophenyl group, 2,3-dichlorophenyl group, 2,4-dichlorophenyl group, 2,5-dichlorophenyl group, 3,4-dichlorophenyl group, 3,5-dichlorophenyl group, 4 -Trifluoromethylphenyl group, 2-methoxyphenyl group, 3-methoxyphenyl group, 4-methoxyphenyl group, , 5-dimethoxyphenyl group, 4-cyanophenyl group, a 4-nitrophenyl group, 4-aminophenyl group, trifluoromethylphenyl group, and pentafluorophenyl group.

The alkoxy group usually has 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. Specific examples thereof include a methoxy group, an ethoxy group, a butoxy group, and a phenoxy group. The substituent that the alkoxy group may have is not particularly limited as long as it does not significantly impair the effects of the present invention. For example, an aryl group, an acyl group, a hydroxy group, an alkoxy group, an aryloxy group, an alkyl group An aryloxy group, an amino group, an aminoalkyl group, a sulfide group and the like can be mentioned, and those having a molecular weight of about 200 or less are usually used. Moreover, in this substituent, hetero atoms, such as oxygen, nitrogen, sulfur, and phosphorus, may be contained.

The amino group usually has 0 to 20 carbon atoms, preferably 0 to 12 carbon atoms. Specific examples thereof include methylamino group, ethylamino group, propylamino group, butylamino group, dimethylamino group, diethylamino group, anilino group, toluidino group, anisidino group, diphenylamino group, N-methyl-N-phenylamino. Groups and the like. The substituent that the amino group may have is not particularly limited as long as it does not significantly inhibit the effects of the present invention, and examples thereof include an aryl group, an acyl group, a hydroxy group, an alkoxy group, an aryloxy group, and an alkyl group. An aryloxy group, an amino group, an aminoalkyl group, a sulfide group and the like can be mentioned, and those having a molecular weight of about 200 or less are usually used. Moreover, in this substituent, hetero atoms, such as oxygen, nitrogen, sulfur, and phosphorus, may be contained.

The alkylthio group usually has 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. Specific examples thereof include a methylthio group, an ethylthio group, a propylthio group, and an isopropylthio group. The substituent that the alkylthio group may have is not particularly limited as long as it does not significantly inhibit the effects of the present invention, and examples thereof include an aryl group, an acyl group, a hydroxy group, an alkoxy group, an aryloxy group, and an alkyl group. An aryloxy group, an amino group, an aminoalkyl group, a sulfide group and the like can be mentioned, and those having a molecular weight of about 200 or less are usually used. Moreover, in this substituent, hetero atoms, such as oxygen, nitrogen, sulfur, and phosphorus, may be contained.

The arylthio group usually has 6 to 20 carbon atoms, preferably 6 to 12 carbon atoms. Specific examples thereof include a phenylthio group and a tolylthio group. The substituent that the arylthio group may have is not particularly limited as long as it does not significantly inhibit the effects of the present invention, and examples thereof include an aryl group, an acyl group, a hydroxy group, an alkoxy group, an aryloxy group, and an alkyl group. An aryloxy group, an amino group, an aminoalkyl group, a sulfide group and the like can be mentioned, and those having a molecular weight of about 200 or less are usually used. Moreover, in this substituent, hetero atoms, such as oxygen, nitrogen, sulfur, and phosphorus, may be contained.

R ¹ and R ² , R ² and R ³ , R ³ and R ¹ may be connected to each other to form a ring.
As a nitrogen-containing compound represented by the above formula (1), it always coexists with 1,4-butanediol, continuously expresses a thermal stability effect, and avoids contamination at the bottom of the distillation column. A compound having a boiling point of 160 to 260 ° C. under atmospheric pressure is preferably used, more preferably 165 to 255 ° C., and particularly preferably 170 to 250 ° C. When the boiling point is higher than this, it is difficult to adjust the nitrogen concentration in the 1,4-butanediol-containing composition of the present invention. When the boiling point is too low, it is difficult to adjust the nitrogen concentration. , Driving operation will be hindered.

Specific examples of such compounds include, for example, primary amines such as octylamine, nonylamine, 1-aminodecane, aniline, phenethylamine, and dipentyl from the viewpoint of basicity and stability in 1,4-BG-containing compositions. Secondary amines such as amine, dihexylamine, diheptylamine, dicyclohexylamine, N-methylaniline, tertiary amines such as tributylamine, tripentylamine, N, N-dimethylaniline, 1,3-propanediamine, N, Diamines such as N-dimethyl-1,6-hexanediamine, 5-membered cyclic amines such as N-butylpyrrole, N-butyl-2,3-dihydropyrrole, N-butylpyrrolidine, 2,3-dihydro-1H-indole 4-aminomethylpiperidine, 4-dimethylaminopyridine, 1,2,3,4-teto Elution fraction of 6-membered cyclic amines such as hydroquinoline, 4-amino-5,6-dihydro-2-methylpyrimidine, 2,3,5,6-tetramethylpyrazine, 3,6-dimethylpyridazine, anion exchange resin Of these, an elution fraction of an anion exchange resin having a primary amine polyethylenediamine skeleton having an NH bond is preferred. In addition, the elution from this anion exchange resin is a polyamine, and the polyamine is a general term for a linear aliphatic hydrocarbon in which two or more primary amino groups are bonded, and in the present invention, the formula (1) A polymer containing 2 or more, preferably 3 to 20, structural units derived from a compound in which any one or more of R ¹ to R ³ of the nitrogen-containing compound is an alkyl group.
Further, those containing an oxygen atom include chain amino alcohols such as 4-aminobutanol and 2-aminobutanol, 2-ethylmorpholine, N-methoxycarbonylmorpholine, prolinol, 3-hydroxypiperidine, 4-hydroxypiperidine, tetrahydro Cyclic amines such as furfurylamine and 3-aminotetrahydropyran are preferred. More preferred are amino alcohols such as prolinol, 3-hydroxypiperidine, 4-aminobutanol and tetrahydrofurfurylamine or amines having a cyclic structure from the viewpoint that the boiling point under atmospheric pressure is close to 1,4BG.

Further, the nitrogen-containing compound represented by the above formula (1) contained in the 1,4-butanediol-containing composition of the present invention may be one type or two or more types.

The 1,4-butanediol-containing composition of the present invention is characterized by containing 1.0 to 50 ppm by weight in terms of nitrogen atom of the nitrogen-containing compound represented by the above formula (1). The 1,4-butanediol-containing composition in this concentration range is obtained by purifying commercially available 1,4BG, 1,4BG or 1,4BG obtained by the above-described conventionally known 1,4BG production method, and then directly It can be added and prepared. Furthermore, it is also possible to obtain by adding the raw material in the above-mentioned conventionally known 1,4BG production method or during the process of the production process of 1,4BG.

For example, in the case of obtaining diacetoxybutene, which is an intermediate obtained by carrying out an acetoxylation reaction using raw material butadiene, acetic acid and oxygen, and hydrolyzing the diacetoxybutene and water, a diacetoxylation reaction Diacetoxybutene may be produced by introducing a compound having a central skeleton represented by formula (1) into a vessel, and a compound having a central skeleton represented by formula (1) is introduced in a subsequent hydrogenation step. 1,4-diacetoxybutane containing nitrogen may be produced. In the hydrolysis step, a compound having a central skeleton represented by the formula (1) may be introduced to obtain a mixture containing 1,4-butanediol, water, and 1-acetoxy-4-hydroxybutane. Further, even if a compound having a central skeleton represented by the formula (1) is introduced into a distillation column for obtaining a purified high-purity product 1,4BG separated from the mixture or a hydrogenation step for removing impurities, Good. For example, when a hydrogenation reaction mixture containing 1,4BG, gamma-butyrolactone and tetrahydrofuran obtained by hydrogenating maleic acid, succinic acid, maleic anhydride and / or fumaric acid as raw materials is used, It may be introduced into the reaction mixture. In addition, when adding in the middle of the process of a manufacturing process in this way, the amount added may add more than 50 weight ppm. That is, the addition amount is adjusted so that the concentration of the nitrogen-containing compound having the central skeleton represented by the formula (1) is 1.0 to 50 ppm by weight in the finally obtained 1,4-butanediol-containing composition. do it.

When the nitrogen-containing compound represented by the above formula (1) is added to the 1,4-butanediol production process, since there is no particular limitation on the boiling point and concentration, any of gas, liquid and solid can be used. It can be added in the state. Further, the nitrogen compound may be added after being dissolved in the raw material or product, solvent, water or the like. You may adjust content of the nitrogen-containing compound contained for another purpose beforehand.

Further, a solid having a nitrogen-containing compound represented by the above formula (1) in a solid that does not normally have a vapor pressure is placed in the process, and the dissolved or eluted portion of the solid is 1,4-butane. You may adjust so that it may become the said numerical range to a diol containing composition. Examples of such a solid material include an anion exchange resin.
In addition, it is directly added to 1,4-butanediol having a purity of 99% or more obtained by purifying 1,4-BG produced by the above-mentioned conventional method so that it becomes 1.0 to 50 ppm by weight. It can also be added to. In this case, it is of course necessary to add a small amount so that the purity of the product 1,4-butanediol after the addition of the nitrogen compound is 99.00% by weight or more and 99.99% by weight or less as specified in the present invention. It is.

The concentration of the nitrogen-containing compound contained in the 1,4-butanediol-containing composition of the present invention is 1.0 ppm by weight to 50 ppm by weight, preferably 2.0 ppm by weight or more, in terms of nitrogen atoms. 47 ppm by weight or less, more preferably 5.0 ppm by weight or more and 43 ppm by weight or less. If the concentration in terms of nitrogen atom is higher than this, the poisoning of the catalyst will increase when it is colored or induced to other products such as polyester and tetrahydrofuran. Moreover, when the density | concentration in nitrogen atom conversion is too low, the effect of quality improvement, such as thermal stability, will fall.

The 1,4-butanediol-containing composition of the present invention preferably has a pH of 7.0 or more, more preferably 7.01 or more and 10.5 or less, and particularly preferably 7.1 or more and 9.0. It is as follows. If the pH is higher than this, the catalyst poisoning tends to increase when it is induced to other products such as coloring or polyester. Moreover, when pH is too low, it exists in the tendency for the effect of the thermal stability improvement by containing a nitrogen compound to fall.

As the compound that may be contained other than 1,4BG and the amine represented by the formula (1) contained in the 1,4-butanediol-containing composition of the present invention, any compound that does not inhibit the effects of the present invention can be used. Although not particularly limited, examples thereof include 2- (4-hydroxybutoxy) -tetrahydrofuran, water, 1-acetoxy-4-hydroxybutane, 2-hydroxytetrahydrofuran, and gamma butyrolactone. Further, if the content of 1,4-BG in the 1,4-butanediol-containing composition and the amount of the amine compound represented by the formula (1) satisfy the amount of the present invention, the effects of the present invention can be obtained. If it is the range which does not inhibit, it will not specifically limit.

The 1,4-butanediol-containing composition of the present invention is preferable for use as a raw material used for producing polyesters such as PBT and polybutylene succinate and gamma-butyrolactone. For example, when a polyester is produced using the 1,4-butanediol-containing composition of the present invention as a raw material, the polyester is subjected to a polycondensation reaction between 1,4-butanediol and at least one of dicarboxylic acid and dicarboxylic acid ester. The concentration of 1,4-butanediol is 99.00 wt% or more and 99.99 wt% or less, and the concentration of the nitrogen-containing compound represented by the above formula (1) in terms of nitrogen atom is A composition containing 1,4-butanediol at 1.0 to 50 ppm by weight is preferred.

In addition, when manufacturing PBT among polyesters, it is more preferable to use the 1,4-butanediol-containing composition of the present invention, and a known manufacturing method can be used as the manufacturing method. Known production methods of PBT are roughly classified into a so-called direct polymerization method using terephthalic acid as a main raw material and a transesterification method using terephthalic acid dialkyl ester as a main raw material. Butanediol is easily converted to tetrahydrofuran during the polymerization reaction, and a method for producing PBT having a low tetrahydrofuran conversion rate is required. The direct polymerization method differs in that water is produced in the initial esterification reaction, and the ester exchange method produces alcohol in the initial transesterification reaction. In view of the height of the raw material basic unit and the improvement effect according to the present invention, the direct polymerization method is preferred. The 1,4-butanediol-containing composition having high thermal stability according to the present invention is very effective as a method for producing PBT with a low conversion rate of tetrahydrofuran and low raw material loss.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, unless it exceeds the summary of this invention, it is not limited to a following example.
In the following examples, 1,4-butanediol and tetrahydrofuran were analyzed by gas chromatography, and 1,4-butanediol was analyzed by the modified area percentage method using the Karl Fischer method (“CA-21” manufactured by Mitsubishi Chemical Corporation). It was calculated by correcting with the amount of water in “Measurement”. Tetrahydrofuran was calculated by the internal standard method (internal standard: n-octadecane). The nitrogen atom-concentrated concentration of the nitrogen-containing compound was calculated from the amount of amine added except for Examples 9 and 17, and Examples 9 and 17 burned the generated combustion gas by burning the sample in an argon / oxygen atmosphere. Measurement was performed with a trace nitrogen meter using a reduced pressure chemiluminescence method (manufactured by Mitsubishi Chemical Analytech Co., Ltd., TN-10 type).

Only the PBT synthesis example (Example 18, Comparative Example 6) was subjected to various analyzes by the following methods. Tetrahydrofuran analysis was calculated by calculating the organic component by gas chromatography using a modified area percentage method and correcting the amount of water by the Karl Fischer method (measured by “CA-200” manufactured by Mitsubishi Chemical Corporation). Tetrahydrofuran production was expressed as mol% relative to terephthalic acid, and was defined as the conversion rate. The intrinsic viscosity (IV) of PBT was determined by the following procedure using an Ubbelohde viscometer. That is, using a mixed solvent of phenol / tetrachloroethane (mass ratio 1/1), at 30 ° C., the polymer solution having a concentration of 1.0 g / dL and the number of falling seconds of the solvent alone were measured, and obtained from the following formula. .

IV = ((1 + 4K _H η _sp ) ^0.5 −1) / (2K _H C)
Where η _sp = (η / η ₀ ) −1, η is the polymer solution falling seconds, η ₀ is the solvent dropping seconds, C is the polymer solution concentration (g / dL), and K _H is the Huggins constant. It is. K _H adopted the 0.33.

<Example 1>
To 5.0 g of commercially available 1,4-butanediol (Mitsubishi Chemical Corporation), 146.9 mg of di-n-hexylamine was added to prepare a 1,4-butanediol solution. 15.7 mg of this 1,4-butanediol solution was further diluted with 25.0 g of commercially available 1,4-butanediol (manufactured by Mitsubishi Chemical Corporation) to give di-n-hexylamine as a concentration in terms of nitrogen atom. A 1,4-butanediol-containing composition (concentration of 1,4-BG: 99.6% by weight) containing 2 ppm by weight was prepared. In addition, it was 7.0 as a result of measuring pH.

This solution was transferred to a 100 mL stainless steel autoclave and heated at 242 ° C. for 1 hour. As a result of analyzing the generation amount of tetrahydrofuran after cooling the autoclave, it was 306 ppm by weight. The results are shown in Table 1.

<Example 2>
In Example 1, 26.2 mg of 1,4-butanediol solution was further diluted with 25.0 g of commercially available 1,4-butanediol, and di-n-hexylamine was added at 2.0 wt.% In terms of nitrogen atom. The same procedure as in Example 1 was carried out except that the composition contained 1,4-butanediol containing ppm (concentration of 1,4-BG: 99.6% by weight). The pH of the 1,4-butanediol-containing composition before heating was 7.1. As a result of analyzing the generation amount of tetrahydrofuran after heating, it was 390 ppm by weight. The results are shown in Table 1.

<Example 3>
In Example 1, 54.2 mg of 1,4-butanediol solution was further diluted with 25.0 g of commercially available 1,4-butanediol, and di-n-hexylamine was added at 5.0 wt% in terms of nitrogen atom. The same procedure as in Example 1 was carried out except that the composition contained 1,4-butanediol containing ppm (concentration of 1,4-BG: 99.6% by weight). The pH of the 1,4-butanediol-containing composition before heating was 8.7. As a result of analyzing the generation amount of tetrahydrofuran after heating, it was 280 ppm by weight. The results are shown in Table 1.

<Example 4>
In Example 1, 243.2 mg of 1,4-butanediol solution was further diluted with 25.0 g of commercially available 1,4-butanediol, and di-n-hexylamine was 20.0 wt% in terms of nitrogen atom. The same procedure as in Example 1 was performed except that a 1,4-butanediol-containing composition containing ppm (the concentration of 1,4-BG: 99.6% by weight) was used for heating.
The pH of the 1,4-butanediol-containing composition before heating was 9.6. As a result of analyzing the tetrahydrofuran generation amount after heating, it was 190 ppm by weight. The results are shown in Table 1.

<Example 5>
In Example 1, 608.0 mg of 1,4-butanediol solution was further diluted with 25.0 g of commercially available 1,4-butanediol, and di-n-hexylamine was 50.0 wt% in terms of nitrogen atom. The same procedure as in Example 1 was performed except that a 1,4-butanediol-containing composition containing ppm (the concentration of 1,4-BG: 99.6% by weight) was used for heating.
The pH of the 1,4-butanediol-containing composition before heating was 10.1. As a result of analyzing the tetrahydrofuran generation amount after heating, it was 63 ppm by weight. The results are shown in Table 1.

<Example 6>
40 g of commercially available 1,4-butanediol (manufactured by Mitsubishi Chemical Corporation) in a 100 mL glass flask and a solid weakly basic anion exchange resin containing a compound having a primary amine polyethylenediamine skeleton (registered trademark: Diaion) , Model: WA20) was charged and stirred at room temperature for 2 hours. After stirring, the anion exchange resin was filtered off. The polyamine having a polyethylenediamine skeleton eluted from the anion exchange resin in the obtained solution (polymer containing 2 to 20 structural units derived from ethyleneamine) was 110 ppm by weight in terms of nitrogen atom.
276.2 mg of this 1,4-butanediol solution was further diluted with 25.0 g of commercially available 1,4-butanediol, and the polyamine eluted from the anion exchange resin contained 1.2 ppm by weight in terms of nitrogen atom. A 1,4-butanediol-containing composition (1,4-BG concentration: 99.6% by weight) was prepared. In addition, it was 7.0 as a result of measuring pH.
25.0 g of this 1,4-butanediol-containing composition was transferred to a 100 mL stainless steel autoclave, purged with nitrogen in the container, and then heated at 242 ° C. for 1 hour. After cooling the autoclave, the 1,4-butanediol solution was taken out and analyzed for the tetrahydrofuran content. As a result, it was 411 ppm by weight. The results are shown in Table 1.

<Example 7>
In Example 6, 1.2 g of the 1,4-butanediol solution was further diluted with 25.0 g of commercially available 1,4-butanediol, and the polyamine eluted from the anion exchange resin was reduced to a nitrogen atom equivalent concentration of 5.0. The same procedures as in Example 1 were conducted except that a 1,4-butanediol-containing composition containing 1, ppm by weight (1,4-BG concentration: 99.6% by weight) was used for heating.
The pH of the 1,4-butanediol-containing composition before heating was 7.7. As a result of analyzing the amount of tetrahydrofuran generated after heating, it was 267 ppm by weight. The results are shown in Table 1.

<Example 8>
In Example 6, 5.5 g of 1,4-butanediol solution was further diluted with 25.0 g of commercially available 1,4-butanediol, and the polyamine eluted from the anion exchange resin was 20.0 in terms of nitrogen atom. The same procedures as in Example 1 were conducted except that a 1,4-butanediol-containing composition containing 1, ppm by weight (1,4-BG concentration: 99.6% by weight) was used for heating.
The 1,4-butanediol-containing composition before heating had a pH of 8.5. As a result of analyzing the tetrahydrofuran generation amount after heating, it was 293 weight ppm. The results are shown in Table 1.

<Example 9>
A 500 mL glass chromatograph tube with a jacket that can be heated by circulating hot water is filled with 300 mL of anion exchange resin (registered trademark: Diaion, model: WA20), and this glass chromatograph tube is commercially available from the top. 1,4-butanediol (Mitsubishi Chemical Corporation) was circulated at 215 g / hr. At this time, the contact temperature between the anion exchange resin and 1,4BG was 55 ° C. A glass 200 mL flask equipped with a glass cooling tube for distillation is charged with 101.7 g of the 1,4BG-containing liquid obtained by the above operation, and subjected to simple distillation at a pressure of 0.2 kPa and a temperature in the flask of 102 ° C. Carried out. As a result, 77.7 g of a distillate was obtained. 25.0 g of the 1,4-butanediol-containing composition (pH = 9.2, nitrogen concentration 43.0 wt ppm) of the obtained distillate was transferred to a 100 mL stainless steel autoclave, and nitrogen substitution in the container was performed. Then, it heated at 242 degreeC for 1 hour. After cooling the autoclave, the 1,4-butanediol solution was taken out and analyzed for the tetrahydrofuran content. As a result, it was 95 ppm by weight. The results are shown in Table 1.

<Example 10>
The same procedure as in Example 3 was performed except that 1-aminodecane was used in place of di-n-hexylamine in Example 3.
The pH of the 1,4-butanediol-containing composition before heating was 7.9. As a result of analyzing the tetrahydrofuran generation amount after heating, it was 240 weight ppm. The results are shown in Table 1.

<Example 11>
The same procedure as in Example 3 was performed except that tri-n-butylamine was used in place of di-n-hexylamine.
The pH of the 1,4-butanediol-containing composition before heating was 8.2. As a result of analyzing the tetrahydrofuran generation amount after heating, it was 354 weight ppm. The results are shown in Table 1.

<Example 12>
The same procedure as in Example 3 was performed except that D, L-prolinol was used instead of di-n-hexylamine in Example 3.
The pH of the 1,4-butanediol-containing composition before heating was 7.6. As a result of analyzing the amount of tetrahydrofuran generated after heating, it was 140 ppm by weight. The results are shown in Table 1.

<Example 13>
In Example 3, the same procedure as in Example 3 was performed except that 3-hydroxypiperidine was used instead of di-n-hexylamine.
The pH of the 1,4-butanediol-containing composition before heating was 7.5. As a result of analyzing the tetrahydrofuran generation amount after heating, it was 150 ppm by weight. The results are shown in Table 1.

<Example 14>
The same procedure as in Example 3 was performed except that 4-aminobutanol was used in place of di-n-hexylamine in Example 3.
The pH of the 1,4-butanediol-containing composition before heating was 7.8. As a result of analyzing the tetrahydrofuran generation amount after heating, it was 190 weight ppm. The results are shown in Table 1.

<Example 15>
The same procedure as in Example 3 was performed except that tetrahydrofurfurylamine was used in place of di-n-hexylamine in Example 3.
The pH of the 1,4-butanediol-containing composition before heating was 7.8. As a result of analyzing the tetrahydrofuran generation amount after heating, it was 250 weight ppm. The results are shown in Table 1.

<Example 16>
In Example 4, instead of commercially available 1,4-butanediol (manufactured by Mitsubishi Chemical Corporation), commercially available 1,4-butanediol (manufactured by Aldrich) was used, and instead of di-n-hexylamine, All operations were performed in the same manner as in Example 4 except that D, L-prolinol was used.
The pH of the 1,4-butanediol-containing composition before heating was 9.1. As a result of analyzing the tetrahydrofuran generation amount after heating, it was 330 weight ppm. The results are shown in Table 1.

<Example 17>
A glass 500 mL flask equipped with a glass condenser for distillation was charged with 349.1 g of 1,4BG-containing liquid and 14.1 mg of D, L-prolinol, pressure 0.2 kPa, temperature in the flask Simple distillation was performed at 115 ° C. As a result, 342.8 g of 1,4BG was obtained as a distillate. The pH of the 1,4-butanediol-containing composition of the obtained distillate was 7.9, and the nitrogen concentration was 3.5 ppm by weight. The obtained 1,4BG solution was transferred to a 100 mL stainless steel autoclave, and after replacing the nitrogen in the container, it was heated at 242 ° C. for 1 hour. After cooling the autoclave, the 1,4-butanediol solution was taken out and analyzed for the tetrahydrofuran content. As a result, it was 110 ppm by weight. The results are shown in Table 1.

<Comparative Example 1>
In Example 1, all operations were carried out in the same manner except that commercially available 1,4-butanediol was directly heated in an autoclave. The pH of the solution before heating was measured and found to be 5.5. As a result of analyzing the tetrahydrofuran content after heating, it was 6800 ppm by weight. The results are shown in Table 1.

<Comparative example 2>
In Example 9, all was carried out in the same manner as in Example 9 except that a solution obtained by simple distillation of commercially available 1,4-butanediol was directly heated without passing 1,4BG through the anion exchange resin. . It was 4.4 as a result of measuring the pH of the solution before a heating. As a result of analyzing the tetrahydrofuran content after heating, it was 1300 ppm by weight. The results are shown in Table 1.

<Comparative Example 3>
In Example 1, 17.0 mg of 1,4-butanediol solution was further diluted with 29.3 g of commercially available 1,4-butanediol, and di-n-hexylamine was added at a concentration of 0.1 wt. The same procedure as in Example 1 was performed except that a 1,4-butanediol-containing composition containing ppm (the concentration of 1,4-BG: 99.6% by weight) was used for heating.
As a result of measuring the pH of the solution before heating, it was 5.6. As a result of analyzing the tetrahydrofuran content after heating, it was 890 ppm by weight. The results are shown in Table 1.

<Comparative Example 4>
In Example 6, 115.0 mg of 1,4-butanediol solution was further diluted with 25.0 g of commercially available 1,4-butanediol, and the polyamine eluted from the anion exchange resin was converted to a nitrogen atom equivalent concentration of 0.5. The same procedures as in Example 1 were conducted except that a 1,4-butanediol-containing composition containing 1, ppm by weight (1,4-BG concentration: 99.6% by weight) was used for heating.
The pH of the 1,4-butanediol-containing composition before heating was 6.9. As a result of analyzing the amount of tetrahydrofuran generated after heating, it was 1104 ppm by weight. The results are shown in Table 1.

<Comparative Example 5>
The same procedure as in Example 2 was performed except that ammonia was used instead of di-n-hexylamine in Example 2. As a result of measuring the pH of the solution before heating, it was 7.0. As a result of analyzing the tetrahydrofuran content after heating, it was 678 ppm by weight. The results are shown in Table 1.

<Example 18>
Production of PBT A reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer, and an exhaust port for decompression contains 113 g of terephthalic acid and 3.1 wt ppm of aminobutanol in terms of nitrogen atom 1,4 -184 g of a butanediol-containing composition (concentration of 1,4-BG: 99.4 wt%, pH 9.3) and 0.7 g of a solution in which 6 wt% of tetrabutyl titanate was previously dissolved as a catalyst were charged with nitrogen-reduced pressure The system was put under a nitrogen atmosphere by replacement. The system was heated to 150 ° C. while stirring in the system, and then heated to 220 ° C. under normal pressure over 1 hour, and an esterification reaction was carried out while distilling water produced for 2 hours. Next, a magnesium acetate tetrahydrate dissolved in water and a 1,4-butanediol solution containing 1% by weight of magnesium acetate tetrahydrate dissolved in 1,4BG (magnesium acetate tetrahydrate, water, 1,4 -The mass ratio of butanediol was 1: 2: 97) 1.3 g. Next, the temperature was raised to 245 ° C. over 1 hour, the pressure was reduced to 0.07 kPa over 1.5 hours, and the polycondensation reaction was performed for 1.1 hours at the same pressure reduction degree. The pressure was returned to normal pressure and the polycondensation was completed. The obtained PBT was extracted as a strand from the bottom of the reaction vessel and immersed in water at 10 ° C., and then the strand was cut with a cutter to obtain a pellet-like PBT.

From the start of pressure reduction after the addition of magnesium acetate to the end of polycondensation was defined as polycondensation time, and the intrinsic viscosity / polycondensation time was defined as polycondensation rate. The polycondensation rate was 0.37 dL / g / h. The THF conversion was analyzed by analyzing the amount of THF in the distillate during the esterification reaction and expressed as mol% per terephthalic acid charged. The THF conversion was 48.0 mol%.

<Comparative Example 6>
PBT was obtained in the same manner as in Example 18 except that 1,4-butanediol-containing composition was replaced with 1,4BG containing no aminobutanol (below the detection limit). As a result, the polycondensation rate was 0.36 dL / g / h. The THF conversion rate was 78.6%.

<Reference Example 1>
Production of THF 2.0 g of commercially available 1,4-butanediol (manufactured by Mitsubishi Chemical Corporation) and 1.2 mg of paratoluenesulfonic acid monohydrate were added to a 9 mL glass vial and stirred at 60 ° C. for 2 hours.
As a result of analyzing the tetrahydrofuran content after heating, it was 662 ppm by weight.

<Reference Example 2>
To 5.0 g of commercially available 1,4-butanediol (Mitsubishi Chemical Corporation), 146.9 mg of di-n-hexylamine was added to prepare a 1,4-butanediol solution. 26.0 mg of this 1,4-butanediol solution was further diluted with 25.0 g of commercially available 1,4-butanediol (manufactured by Mitsubishi Chemical Corporation) to give di-n-hexylamine as a concentration in terms of nitrogen atom. A 1,4-butanediol-containing composition (concentration of 1,4-BG: 99.6% by weight) containing 2 ppm by weight was prepared. In addition, it was 7.0 as a result of measuring pH.
2.0 g of the prepared 1,4-butanediol-containing composition was placed in a 9 mL glass vial, 1.2 mg of paratoluenesulfonic acid monohydrate was added, and the mixture was stirred at 60 ° C. for 2 hours.
As a result of analyzing the tetrahydrofuran content after heating, it was 646 weight ppm.

<Reference Example 3>
In Reference Example 2, 521.8 mg of 1,4-butanediol solution was further diluted with 25.0 g of commercially available 1,4-butanediol, and di-n-hexylamine was 40.0% by weight in terms of nitrogen atom. The same procedure as in Reference Example 2 was carried out except that the composition contained 1,4-butanediol containing ppm (concentration of 1,4-BG: 99.6% by weight).
As a result of analyzing the tetrahydrofuran content after heating, it was 408 ppm by weight.

<Reference Example 4>
In Reference Example 2, 792.2 mg of 1,4-butanediol solution was further diluted with 25.0 g of commercially available 1,4-butanediol, and di-n-hexylamine was 60.0% by weight in terms of nitrogen atom. The same procedure as in Reference Example 2 was carried out except that the composition contained 1,4-butanediol containing ppm (concentration of 1,4-BG: 99.6% by weight).
As a result of analyzing the tetrahydrofuran content after heating, it was 118 ppm by weight.

<Reference Example 5>
In Reference Example 2, 1083.3 mg of 1,4-butanediol solution was further diluted with 25.0 g of commercially available 1,4-butanediol, and di-n-hexylamine was 80.0 wt% in terms of nitrogen atom. The same procedure as in Reference Example 2 was carried out except that the composition contained 1,4-butanediol containing ppm (concentration of 1,4-BG: 99.6% by weight).
As a result of analyzing the tetrahydrofuran content after heating, it was 91 ppm by weight.

From Examples 1 to 17 and Comparative Examples 1 to 5, the 1,4-butanediol-containing composition containing a specific amount of the nitrogen-containing compound of the present invention can suppress the amount of THF generated by heating, and is thermally stable. Is high.
Further, when Example 18 in which PBT is produced using the 1,4-butanediol-containing composition of the present invention and Comparative Example 6 are compared, it can be seen that Example 18 can suppress the THF conversion rate more than Comparative Example 6.
Further, in comparison with Reference Examples 1 to 5 in which THF is produced using the 1,4-butanediol-containing composition of the present invention, if the amine concentration in terms of nitrogen atom becomes too high, the THFation reaction is inhibited. I understand.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on a Japanese patent application filed on July 4, 2011 (Japanese Patent Application No. 2011-148327) and a Japanese patent application filed on August 1, 2011 (Japanese Patent Application No. 2011-168645). Incorporated herein by reference.

Claims

The concentration of 1,4-butanediol is 99.00 wt% or more and 99.99 wt% or less, and the concentration of the nitrogen-containing compound represented by the following formula (1) in terms of nitrogen atom is 1.0 to 50 1,4-butanediol-containing composition that is ppm by weight.

(In the above formula (1), R 1 to R 3 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, an alkoxy group, a hydroxy group, an amino group, an alkylthio group, or an arylthio group. The group may further have a substituent, and the substituent may contain a hetero atom, and R 1 and R 2 , R 2 and R 3 , R 3 and R 1 are Each may be linked to each other to form a ring, except that R 1 to R 3 are all hydrogen atoms.)
The 1,4-butanediol-containing composition according to claim 1, wherein the pH is 7.01 or more and 10.5 or less.
A method for producing a polyester by polycondensation reaction of 1,4-butanediol with at least one of dicarboxylic acid and dicarboxylic acid ester, wherein the concentration of 1,4-butanediol as a raw material is 99.00% by weight or more A 1,4-butanediol-containing composition having a content of 99.99% by weight or less and having a nitrogen atom-converted concentration of the nitrogen-containing compound represented by the following formula (1) of 1.0 to 50 ppm by weight is used. A method for producing polyester.

(In the above formula (1), R 1 to R 3 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, an alkoxy group, a hydroxy group, an amino group, an alkylthio group, or an arylthio group. The group may further have a substituent, and the substituent may contain a hetero atom, and R 1 and R 2 , R 2 and R 3 , R 3 and R 1 are Each may be linked to each other to form a ring, except that R 1 to R 3 are all hydrogen atoms.)