JP3834836B2 - Method for producing alicyclic polycarboxylic acid ester - Google Patents

Description

［式中、Ｘは単結合、−ＣＯ−、−Ｏ−、−ＣＨ₂−、−ＣＨ（−ＣＨ₃）−又は−Ｃ（−ＣＨ₃）₂−を表す。］
【００１６】
【化６】

［式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴は同一又は異なって、水素原子、メチル基又はカルボキシル基を表す。］
【００１７】
［エステル化工程］
上記芳香族ポリカルボン酸無水物としては、相当するポリカルボン酸の一無水物、二無水物又は三無水物が挙げられる。
【００１８】
ポリカルボン酸一無水物としては、フタル酸無水物、1,2,4−ベンゼントリカルボン酸無水物、3−メチルフタル酸無水物、4−メチルフタル酸無水物、3,4,5,6−テトラメチルフタル酸無水物、5−メチルベンゼン−1,2,4−トリカルボン酸無水物、6−メチルベンゼン−1,2,4−トリカルボン酸無水物、3−メチルベンゼン−1,2,4−トリカルボン酸無水物などが例示される。
【００１９】
ポリカルボン酸二無水物としては、ビフェニル−3,3',4,4'−テトラカルボン酸二無水物、ビフェニルエーテル−3,3',4,4'−テトラカルボン酸二無水物、ベンゾフェノン−3,3',4,4'−テトラカルボン酸二無水物、ビフェニルメタン−3,3',4,4'−テトラカルボン酸二無水物、エチリデン−4,4'−ビス（1,2−ベンゼンジカルボン酸無水物）、プロピリデン−4,4'−ビス（1,2−ベンゼンジカルボン酸無水物）、1,2,3,4−ベンゼンテトラカルボン酸二無水物、1,2,4,5−ベンゼンテトラカルボン酸二無水物、3−メチルベンゼン−1,2,4,5−テトラカルボン酸二無水物、3,6−ジメチルベンゼン−1,2,4,5−テトラカルボン酸二無水物などが例示される。
【００２０】
ポリカルボン酸三無水物としては、ベンゼンヘキサカルボン酸三無水物などが例示される。
【００２１】
脂肪族アルコールとしては、炭素数１〜６の直鎖状、分岐鎖状又は環状の脂肪族アルコールが推奨され、具体的には、メタノール、エタノール、1−プロパノール、2−プロパノール、イソブタノール、アミルアルコール、シクロヘキサノールなどが例示され、中でもメタノール、エタノール、1−プロパノールが好ましい。
【００２２】
脂肪族アルコールの適用量としては、エステル化に必要な化学量論以上の量であり、且つエステル化工程に続く水素化工程で芳香族ポリカルボン酸エステルが溶解し得る量であれば特に限定されない。具体的には、芳香族ポリカルボン酸類に対し、１〜１００倍当量が例示され、特に２〜５０倍当量が推奨される。
【００２３】
水素化工程で使う耐圧装置に原料である芳香族ポリカルボン酸類と脂肪族アルコールとを一括して仕込み、高温高圧下でエステル化を行う方法は、特別なエステル化装置を必要とせず、エステル化反応をより効率的に進める上で好ましい。
【００２４】
エステル化反応温度としては、１００〜２８０℃が例示され、特に１８０〜２３０℃が推奨される。
【００２５】
触媒を用いないでエステル化することにより、触媒除去の必要はなく、芳香族エステルを単離する必要がないため、同一反応器でエステル化、水素化の両工程を行うことができるなどの利点が得られる。
【００２６】
エステル化の反応雰囲気を構成する不活性ガスとしては、窒素、水素などが例示される。
【００２７】
反応時間としては、０．１〜１０時間が例示されるが、当該時間は、実用的な観点から適宜選択することができる。即ち、本発明に係るエステル化工程は、必ずしもエステル化を完了せしめる必要はなく、反応生成物が完全エステル化物と部分エステル化物との混合物の状態で次の水素化工程に供すればよい。より具体的には、０．５〜１時間が推奨される。
【００２８】
［水素化工程］
エステル化反応の後、貴金属系水素化触媒を仕込み、水素化反応を行う。
【００２９】
貴金属系水素化触媒としては、水素化触媒を調製するために通常使用される担体に、ルテニウム、パラジウムなどの貴金属を担持してなる触媒が例示される。特に好ましいのは安価なルテニウム系触媒である。
【００３０】
かかる担体としては、活性炭、アルミナ、シリカ、シリカアルミナ、酸化ジルコニウム、酸化チタンなどが例示される。
【００３１】
貴金属の担持量としては、貴金属換算で０．１〜１０重量％、好ましくは１〜５％が推奨される。
【００３２】
触媒の形態は、特に限定されず、その水素化工程の形態に応じて粉末状、タブレット状など適宣選択して使用される。
【００３３】
水素化触媒の適用量は、芳香族ポリカルボン酸エステルの種類や用いる触媒の担持量によって適宜選択できるものの、通常、芳香族ポリカルボン酸エステルに対し、０．５〜２０重量％が例示され、１〜５重量％が推奨される。
【００３４】
水素化反応時の溶媒としては、好ましくはエステル化で用いた溶媒と同種の脂肪族アルコールをそのまま使用する。かかる手法を採ることにより、工程を簡略化することができる。
【００３５】
水素圧力としては、２〜２００kg/cm²Ｇが例示され、好ましくは２０〜１５０kg/cm²Ｇである。水素圧力が２kg/cm²Ｇ未満の場合には、反応時間が長くなり、未反応の芳香族化合物が残りやすい傾向がある。一方、水素圧力が２００kg/cm²Ｇを越える場合には、反応が急激に進み、反応温度の制御が行いにくくなる傾向にあり、いずれも好ましくない。
【００３６】
水素化反応温度としては、６０〜１７０℃が例示され、特に１００〜１５０℃が推奨される。反応温度が６０℃未満の場合には反応時間が長くなり、未反応の芳香族化合物が残りやすい傾向にある。一方、反応温度が１７０℃を超えると、エステルのカルボニルが攻撃を受け、副生成物が出来やすくなる傾向となる。
【００３７】
このような水素化反応条件の場合、例えば反応時間は０．５〜２０時間程度で反応が完結する。反応の進行状態及び終了に関しては、圧力計から消費水素量を求めることで判断することができる。
【００３８】
一般に、芳香族ポリカルボン酸の完全エステル化物を調製するためには長時間の反応が必要であるが、本発明の如く、エステル化工程とそれに続く水素化工程とを好ましくは同一の脂肪族アルコールの存在下で行うことにより、上記部分エステル化物は、水素化反応と併発して更なるエステル化が進行する結果、芳香族ポリカルボン酸類から脂環式ポリカルボン酸エステルへの選択性が飛躍的に向上する。
【００３９】
反応後、触媒を濾過操作により回収し、次回の水素化反応に繰り返し使用することが出来、触媒原単位の低減ができる。
【００４０】
【実施例】
以下、実施例を掲げて本発明を詳しく説明する。尚、各実施例において、所定の芳香族ポリカルボン酸類に対する脂肪族アルコールの当量倍数をＺで表す。
【００４１】
実施例１
５００mlの電磁攪拌機付きオートクレーブにビフェニル−3,3',4,4'−テトラカルボン酸二無水物２０ｇ及びメタノール８０ｇ（Ｚ＝９．３）を仕込み、温度２００℃で３０分間エステル化を行った。次いで、この溶液に活性炭に５重量％ルテニウムを担持させた触媒１ｇを添加し、水素圧力１００kg/cm²Ｇ、温度１３０℃で水素化を行った。反応時間３時間で水素の吸収が停止し、その時の水素吸収量は理論水素吸収量の９８．５％であった。反応液中の活性炭担持ルテニウム触媒を濾別し、反応物を紫外分光光度計（ＵＶ計）で分析したところ、ベンゼン核の吸収はみられず、水素化反応は完結していることを確認した。ガスクロマトグラフィー（ＧＬＣ）による分析の結果、ジシクロヘキシル−3,3',4,4'−テトラカルボン酸テトラメチルエステルの純度は９８．１％であった。
【００４２】
実施例２
実施例１と同様のオートクレーブにベンゾフェノン−3,3',4,4'−テトラカルボン酸二無水物２０ｇ及びメタノール８０ｇ（Ｚ＝１０．０）を仕込み、温度２００℃で３０分間エステル化を行った。この溶液にアルミナに５重量％ルテニウムを担持させた触媒１ｇを添加し、水素圧力１００kg/cm²Ｇ、温度１３０℃で水素化を行った。反応時間４時間で水素の吸収が停止し、その時の水素吸収量は理論水素吸収量の１０２．５％であった。反応液中のアルミナに担持したルテニウム触媒を濾別し、反応物をＵＶ計で分析したところ、ベンゼン核の吸収はみられず、水素化反応は完結していることを確認した。ＧＬＣによる分析の結果、ジシクロヘキシルケトン−3,3',4,4'−テトラカルボン酸テトラメチルエステルの純度は８８．７％であった。
【００４３】
実施例３
実施例１と同様のオートクレーブに1,2,4−ベンゼントリカルボン酸無水物３０ｇ及びメタノール７０ｇ（Ｚ＝４．７）を仕込み、温度２２０℃で１時間エステル化を行った。この溶液に活性炭に５重量％ルテニウムを担持させた触媒１ｇを添加し、水素圧力１２０kg/cm²Ｇ、温度１２０℃で水素化を行った。反応時間２．５時間で水素の吸収が停止し、その時の水素吸収量は理論水素吸収量の９９．１％であった。
【００４４】
反応液中の活性炭担持ルテニウム触媒を濾別し、反応物をＵＶ計で分析したところ、ベンゼン核の吸収はみられず、水素化反応が完結していることを確認した。又、ＧＬＣによる分析の結果、シクロヘキサン−1,2,4−トリカルボン酸トリメチルエステルの純度は９７．２％であった。
【００４５】
実施例４
実施例１と同様のオートクレーブに1,2,4−ベンゼントリカルボン酸３０ｇ及びメタノール７０ｇ（Ｚ＝５．１）を仕込み、温度２２０℃で１時間エステル化を行った。この溶液に活性炭に５重量％ルテニウムを担持させた触媒１ｇを添加し、水素圧力１２０kg/cm²Ｇ、温度１２０℃で水素化を行った。反応時間３．５時間で水素の吸収が停止し、その時の水素吸収量は理論水素吸収量の９９．１％であった。
【００４６】
反応液中の活性炭担持ルテニウム触媒を濾別し、反応物をＵＶ計で分析したところ、ベンゼン核の吸収はみられず、水素化反応が完結していることを確認した。又、ＧＬＣによる分析の結果、シクロヘキサン−1,2,4−トリカルボン酸トリメチルエステルの純度は９５．６％であった。
【００４７】
実施例５
実施例１と同様のオートクレーブにベンゼン−1,2,4,5−テトラカルボン酸二無水物２５ｇ及びメタノール７５ｇ（Ｚ＝５．１）を仕込み、温度２２０℃で１時間エステル化を行った。この溶液に活性炭に５重量％のルテニウムを担持させた触媒０．５ｇを添加し、水素圧力１００kg/cm²Ｇ、温度１３０℃で水素化を行った。反応時間２時間で水素の吸収が停止し、このときの水素吸収量は理論水素吸収量の９４．１％であった。反応液中の活性炭担持ルテニウム触媒を濾別し、反応物をＵＶ計で分析したところ、ベンゼン核の吸収はみられず、水素化反応は完結していることを確認した。ＧＬＣによる分析の結果、シクロヘキサン−1,2,4,5−テトラカルボン酸テトラメチルエステルの純度は９１．４％であった。
【００４８】
実施例６
実施例１と同様のオートクレーブに3−メチルベンゼン−1,2,4−トリカルボン酸無水物３０ｇ及びメタノール７０ｇ（Ｚ＝５．０）を仕込み、温度２２０℃で１時間エステル化を行った。この溶液に活性炭に５重量％のパラジウムを担持させた触媒１ｇを添加し、水素圧力１２０kg/cm²Ｇ、温度１２０℃で水素化を行った。反応時間４時間で水素の吸収が停止し、このときの水素吸収量は理論水素吸収量の９７．２％であった。反応液中の活性炭担持パラジウム触媒を濾別し反応物をＵＶ計で分析したところ、ベンゼン核の吸収はみられず、水素化反応は完結していることを確認した。ＧＬＣによる分析の結果、3−メチルシクロヘキサン−1,2,4−トリカルボン酸トリメチルエステルの純度は８６．４％であった。
【００４９】
実施例７
実施例１と同様のオートクレーブにベンゼン−1,2,4,5−テトラカルボン酸二無水物２５ｇ及び1−プロパノール７５ｇ（Ｚ＝２．７）を仕込み、温度２２０℃で１時間エステル化を行った。この溶液に活性炭に５重量％のルテニウムを担持させた触媒０．５ｇを添加し、水素圧力１００kg/cm²Ｇ、温度１３０℃で水素化を行った。反応時間２．５時間で水素の吸収が停止し、このときの水素吸収量は理論水素吸収量の９８．１％であった。反応液中の活性炭担持ルテニウム触媒を濾別し、反応物をＵＶ計で分析したところ、ベンゼン核の吸収はみられず、水素化反応は完結していることを確認した。又、ＧＬＣによる分析の結果、シクロヘキサン−1,2,4,5−テトラカルボン酸テトラプロピルエステルの純度は９５．９％であった。
【００５０】
比較例１
前段のエステル化工程をしない以外は実施例１と全く同一の条件で水素化を実施した。その結果、反応時間７時間で水素の吸収が停止し、その時の水素吸収量は理論水素吸収量の６８．９％であった。反応液中の活性炭担持ルテニウム触媒を濾別し、反応物をＵＶ計で分析を行ったところ、ベンゼン核の吸収が見られ、核水素化率は７３．５％であった。又、ＧＬＣによる分析の結果、ジシクロヘキシル−3,3',4,4'−テトラカルボン酸テトラメチルエステルの純度は３８．６％であった。
【００５１】
比較例２
水素化触媒に安定化ニッケル触媒を用いた以外は実施例１と同様にしてエステル化し、次いで１７０℃で水素化した。しかしながら、反応時間７時間でも水素の吸収が全く見られず、水素化反応は進行しなかった。
【００５２】
【発明の効果】
本発明方法を適用することにより、工業的に有利な条件下で脂環式ポリカルボン酸エステルを高純度、高収率で得ることができる。
【化７】

【化８】

[0001]
[Industrial application fields]
The present invention relates to a method for producing an alicyclic polycarboxylic acid ester. The alicyclic polycarboxylic acid ester is useful as a raw material for alicyclic polycarboxylic acid and its acid anhydride, which are materials useful as raw materials for solvent-soluble polyimides and the like.
[0002]
[Prior art]
As a method for producing an alicyclic polycarboxylic acid ester, an aromatic polycarboxylic acid or an acid anhydride thereof (hereinafter collectively referred to as “aromatic polycarboxylic acids”) is nuclear hydrogenated to alicyclic polycarboxylic acids (aliphatic A cyclic polycarboxylic acid or an anhydride thereof) and a method of esterification or a method of esterifying an aromatic polycarboxylic acid and then hydrogenating it. However, the method of hydrogenating aromatic carboxylic acids as they are is not practical due to the disadvantage that the apparatus requires a corrosion-resistant apparatus or has poor selectivity, and the alicyclic polycarboxylic acid can be used only by the latter method. Esters are difficult to produce industrially.
[0003]
Nuclear hydrogenation of aromatic polycarboxylic acid esters is known. For example, Kikuchi et al. Hydrogenated biphenyl-3,3 ′, 4,4′-tetracarboxylic acid tetramethyl ester using a rhodium catalyst to dimethyl-3,3 ′, 4,4′-tetracarboxylic acid tetramethyl. Esters have been obtained (Japanese Patent Laid-Open No. 1-96147).
[0004]
However, in this hydrogenation method, when the carboxylic acid which is not esterified remains in the raw material, the selectivity is extremely deteriorated. Therefore, the raw material ester must be completely esterified and have high purity. Met.
[0005]
The following methods can be considered as methods for completely esterifying aromatic polycarboxylic acids.
[0006]
(1) A method of obtaining an aromatic polycarboxylic acid ester by esterifying an aromatic polycarboxylic acid in the presence of an alcohol and an acid catalyst.
[0007]
(2) A method in which an aromatic polycarboxylic acid ester is obtained by completely esterifying an aromatic polycarboxylic acid with an alcohol at high temperature and without catalyst.
[0008]
However, in the method (1), an acid-resistant catalyst is required in order to use an acid catalyst, and in addition, in order to perform hydrogenation, it is necessary to completely remove the acid and alcohol that are catalysts. Further, in the method (2), esterification does not proceed completely unless water produced continuously is removed. Furthermore, both of the methods (1) and (2) involve many steps of ester production, which is not preferable as an industrial production method.
[0009]
Furthermore, in any case, it is necessary to once separate the aromatic polycarboxylic acid ester and perform hydrogenation again, and there is still room for improvement as a method for producing the alicyclic polycarboxylic acid ester.
[0010]
[Problems to be solved by the invention]
An object of this invention is to provide the novel useful manufacturing method of alicyclic polycarboxylic acid ester.
[0011]
[Means for Solving the Problems]
The inventors of the present invention, in earnest study to achieve the above-mentioned problems, are biphenyl-3,3 ′, 4,4′-tetracarboxylic dianhydride, which is a kind of aromatic polycarboxylic acid anhydride, and aliphatic. An alcohol is esterified in the absence of a catalyst, and the resulting mixture of aromatic polycarboxylic acid esters having different degrees of esterification is not separated, a hydrogenation catalyst is charged into the reaction system, and a nucleus is formed in the presence of the aliphatic alcohol. It has been found that a predetermined effect can be obtained by hydrogenation.
[0012]
As a result of subsequent studies, the present inventors have found that the effect of using the esterification step and the hydrogenation step in combination is not only the production of dicyclohexyl-3,3 ′, 4,4′-tetracarboxylic acid tetraester, but also various effects. The present invention has been found to be effective in the production of alicyclic polycarboxylic acid esters, and the present invention has been completed based on such findings.
[0013]
That is, the method for producing an alicyclic polycarboxylic acid ester according to the present invention preferably comprises an aromatic polycarboxylic acid represented by the general formula (1) or an acid anhydride thereof and an aliphatic alcohol in the absence of a catalyst. Aromatic polycarboxylic acid ester mixtures having different degrees of esterification are obtained by heating in an active gas atmosphere (hereinafter referred to as “esterification step”), and then heated in the presence of a noble metal catalyst and an aliphatic alcohol to effect nuclear hydrogenation. (Hereinafter referred to as “hydrogenation step”).
[0014]
HOOC-A-COOH (1)
[In formula, A shows the aromatic carboxylic acid residue represented by general formula (a) or general formula (b). ]
[0015]
[Chemical formula 5]

[Wherein, X represents a single bond, —CO—, —O—, —CH ₂ —, —CH (—CH ₃ ) — or —C (—CH ₃ ) ₂ —. ]
[0016]
[Chemical 6]

[Wherein, R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents a hydrogen atom, a methyl group or a carboxyl group. ]
[0017]
[Esterification process]
Examples of the aromatic polycarboxylic acid anhydride include monoanhydride, dianhydride, and dianhydride of the corresponding polycarboxylic acid.
[0018]
Polycarboxylic acid anhydrides include phthalic anhydride, 1,2,4-benzenetricarboxylic anhydride, 3-methylphthalic anhydride, 4-methylphthalic anhydride, 3,4,5,6-tetramethyl. Phthalic anhydride, 5-methylbenzene-1,2,4-tricarboxylic anhydride, 6-methylbenzene-1,2,4-tricarboxylic anhydride, 3-methylbenzene-1,2,4-tricarboxylic acid An anhydride etc. are illustrated.
[0019]
Polycarboxylic dianhydrides include biphenyl-3,3 ', 4,4'-tetracarboxylic dianhydride, biphenyl ether-3,3', 4,4'-tetracarboxylic dianhydride, benzophenone- 3,3 ′, 4,4′-tetracarboxylic dianhydride, biphenylmethane-3,3 ′, 4,4′-tetracarboxylic dianhydride, ethylidene-4,4′-bis (1,2- Benzenedicarboxylic acid anhydride), propylidene-4,4'-bis (1,2-benzenedicarboxylic acid anhydride), 1,2,3,4-benzenetetracarboxylic dianhydride, 1,2,4,5 -Benzenetetracarboxylic dianhydride, 3-methylbenzene-1,2,4,5-tetracarboxylic dianhydride, 3,6-dimethylbenzene-1,2,4,5-tetracarboxylic dianhydride Etc. are exemplified.
[0020]
Examples of the polycarboxylic acid dianhydride include benzenehexacarboxylic acid dianhydride.
[0021]
As the aliphatic alcohol, a linear, branched or cyclic aliphatic alcohol having 1 to 6 carbon atoms is recommended. Specifically, methanol, ethanol, 1-propanol, 2-propanol, isobutanol, amyl Alcohol, cyclohexanol and the like are exemplified, and methanol, ethanol and 1-propanol are particularly preferable.
[0022]
The application amount of the aliphatic alcohol is not particularly limited as long as the amount is higher than the stoichiometric amount necessary for the esterification and the aromatic polycarboxylic acid ester can be dissolved in the hydrogenation step following the esterification step. . Specifically, 1-100 times equivalent is illustrated with respect to aromatic polycarboxylic acid, and 2-50 times equivalent is recommended especially.
[0023]
The method of batch-feeding aromatic polycarboxylic acids and aliphatic alcohols as raw materials into a pressure device used in the hydrogenation process and performing esterification under high temperature and pressure does not require a special esterification device, and esterification It is preferable for promoting the reaction more efficiently.
[0024]
As esterification reaction temperature, 100-280 degreeC is illustrated, and 180-230 degreeC is recommended especially.
[0025]
By esterifying without using a catalyst, it is not necessary to remove the catalyst and it is not necessary to isolate the aromatic ester, so that both esterification and hydrogenation steps can be performed in the same reactor. Is obtained.
[0026]
Nitrogen, hydrogen, etc. are illustrated as an inert gas which comprises the reaction atmosphere of esterification.
[0027]
Examples of the reaction time include 0.1 to 10 hours, and the time can be appropriately selected from a practical viewpoint. That is, the esterification step according to the present invention does not necessarily need to complete the esterification, and the reaction product may be subjected to the next hydrogenation step in the state of a mixture of a completely esterified product and a partially esterified product. More specifically, 0.5 to 1 hour is recommended.
[0028]
[Hydrogenation process]
After the esterification reaction, a noble metal hydrogenation catalyst is charged and the hydrogenation reaction is performed.
[0029]
Examples of the noble metal hydrogenation catalyst include a catalyst in which a noble metal such as ruthenium or palladium is supported on a carrier usually used for preparing the hydrogenation catalyst. Particularly preferred is an inexpensive ruthenium-based catalyst.
[0030]
Examples of such carriers include activated carbon, alumina, silica, silica alumina, zirconium oxide, titanium oxide and the like.
[0031]
The supported amount of noble metal is 0.1 to 10% by weight, preferably 1 to 5% in terms of noble metal.
[0032]
The form of the catalyst is not particularly limited, and is suitably selected from powder form, tablet form and the like depending on the form of the hydrogenation step.
[0033]
The application amount of the hydrogenation catalyst can be appropriately selected depending on the type of the aromatic polycarboxylic acid ester and the supported amount of the catalyst used, but usually 0.5 to 20% by weight is exemplified with respect to the aromatic polycarboxylic acid ester, 1-5% by weight is recommended.
[0034]
As the solvent for the hydrogenation reaction, the same kind of aliphatic alcohol as that used in the esterification is preferably used as it is. By adopting such a method, the process can be simplified.
[0035]
Examples of the hydrogen pressure include 2-200 kg / cm ² G, preferably 20-150 kg / cm ² G. When the hydrogen pressure is less than ² kg / cm ² G, the reaction time tends to be long and unreacted aromatic compounds tend to remain. On the other hand, when the hydrogen pressure exceeds 200 kg / cm ² G, the reaction proceeds rapidly, and it tends to be difficult to control the reaction temperature.
[0036]
As a hydrogenation reaction temperature, 60-170 degreeC is illustrated, and 100-150 degreeC is especially recommended. When the reaction temperature is less than 60 ° C., the reaction time becomes long and unreacted aromatic compounds tend to remain. On the other hand, when the reaction temperature exceeds 170 ° C., the carbonyl of the ester is attacked and tends to be a by-product.
[0037]
In the case of such hydrogenation reaction conditions, for example, the reaction is completed in about 0.5 to 20 hours. The progress and termination of the reaction can be determined by determining the amount of hydrogen consumed from the pressure gauge.
[0038]
In general, a long reaction time is required to prepare a completely esterified product of an aromatic polycarboxylic acid. As in the present invention, the esterification step and the subsequent hydrogenation step are preferably the same aliphatic alcohol. As a result of the further esterification in conjunction with the hydrogenation reaction, the selectivity from aromatic polycarboxylic acids to alicyclic polycarboxylic acid esters is dramatically improved. To improve.
[0039]
After the reaction, the catalyst can be recovered by filtration and used repeatedly for the next hydrogenation reaction, thereby reducing the catalyst unit.
[0040]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples. In each example, Z represents the equivalent multiple of the aliphatic alcohol relative to the predetermined aromatic polycarboxylic acid.
[0041]
Example 1
A 500 ml autoclave with a magnetic stirrer was charged with 20 g of biphenyl-3,3 ′, 4,4′-tetracarboxylic dianhydride and 80 g of methanol (Z = 9.3), and esterified at a temperature of 200 ° C. for 30 minutes. . Next, 1 g of a catalyst in which 5 wt% ruthenium was supported on activated carbon was added to this solution, and hydrogenation was performed at a hydrogen pressure of 100 kg / cm ² G and a temperature of 130 ° C. Hydrogen absorption stopped at the reaction time of 3 hours, and the hydrogen absorption at that time was 98.5% of the theoretical hydrogen absorption. The activated carbon-supported ruthenium catalyst in the reaction solution was filtered off, and the reaction product was analyzed with an ultraviolet spectrophotometer (UV meter). As a result, absorption of benzene nuclei was not observed and the hydrogenation reaction was confirmed to be complete. . As a result of analysis by gas chromatography (GLC), the purity of dicyclohexyl-3,3 ′, 4,4′-tetracarboxylic acid tetramethyl ester was 98.1%.
[0042]
Example 2
In the same autoclave as in Example 1, 20 g of benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride and 80 g of methanol (Z = 10.0) were charged and esterified at a temperature of 200 ° C. for 30 minutes. It was. To this solution, 1 g of a catalyst in which 5 wt% ruthenium was supported on alumina was added, and hydrogenation was performed at a hydrogen pressure of 100 kg / cm ² G and a temperature of 130 ° C. Hydrogen absorption stopped at a reaction time of 4 hours, and the hydrogen absorption at that time was 102.5% of the theoretical hydrogen absorption. The ruthenium catalyst supported on alumina in the reaction solution was filtered off and the reaction product was analyzed with a UV meter. As a result, no absorption of benzene nuclei was observed, and it was confirmed that the hydrogenation reaction was complete. As a result of analysis by GLC, the purity of dicyclohexylketone-3,3 ′, 4,4′-tetracarboxylic acid tetramethyl ester was 88.7%.
[0043]
Example 3
In the same autoclave as in Example 1, 30 g of 1,2,4-benzenetricarboxylic acid anhydride and 70 g of methanol (Z = 4.7) were charged, and esterification was performed at a temperature of 220 ° C. for 1 hour. To this solution was added 1 g of a catalyst in which 5 wt% ruthenium was supported on activated carbon, and hydrogenation was performed at a hydrogen pressure of 120 kg / cm ² G and a temperature of 120 ° C. Hydrogen absorption stopped at a reaction time of 2.5 hours, and the hydrogen absorption at that time was 99.1% of the theoretical hydrogen absorption.
[0044]
The activated carbon-supported ruthenium catalyst in the reaction solution was filtered off, and the reaction product was analyzed with a UV meter. As a result, absorption of benzene nuclei was not observed, and it was confirmed that the hydrogenation reaction was complete. As a result of analysis by GLC, the purity of cyclohexane-1,2,4-tricarboxylic acid trimethyl ester was 97.2%.
[0045]
Example 4
In the same autoclave as in Example 1, 30 g of 1,2,4-benzenetricarboxylic acid and 70 g of methanol (Z = 5.1) were charged, and esterification was performed at a temperature of 220 ° C. for 1 hour. To this solution was added 1 g of a catalyst in which 5 wt% ruthenium was supported on activated carbon, and hydrogenation was performed at a hydrogen pressure of 120 kg / cm ² G and a temperature of 120 ° C. Hydrogen absorption stopped at a reaction time of 3.5 hours, and the hydrogen absorption at that time was 99.1% of the theoretical hydrogen absorption.
[0046]
The activated carbon-supported ruthenium catalyst in the reaction solution was filtered off, and the reaction product was analyzed with a UV meter. As a result, absorption of benzene nuclei was not observed, and it was confirmed that the hydrogenation reaction was complete. As a result of analysis by GLC, the purity of cyclohexane-1,2,4-tricarboxylic acid trimethyl ester was 95.6%.
[0047]
Example 5
The same autoclave as in Example 1 was charged with 25 g of benzene-1,2,4,5-tetracarboxylic dianhydride and 75 g of methanol (Z = 5.1) and esterified at a temperature of 220 ° C. for 1 hour. 0.5 g of a catalyst in which 5% by weight of ruthenium was supported on activated carbon was added to this solution, and hydrogenation was performed at a hydrogen pressure of 100 kg / cm ² G and a temperature of 130 ° C. Hydrogen absorption stopped at the reaction time of 2 hours, and the hydrogen absorption at this time was 94.1% of the theoretical hydrogen absorption. The activated carbon-supported ruthenium catalyst in the reaction solution was filtered off and the reaction product was analyzed with a UV meter. As a result, no absorption of benzene nuclei was observed, and it was confirmed that the hydrogenation reaction was complete. As a result of analysis by GLC, the purity of cyclohexane-1,2,4,5-tetracarboxylic acid tetramethyl ester was 91.4%.
[0048]
Example 6
In the same autoclave as in Example 1, 30 g of 3-methylbenzene-1,2,4-tricarboxylic acid anhydride and 70 g of methanol (Z = 5.0) were charged, and esterification was performed at a temperature of 220 ° C. for 1 hour. 1 g of a catalyst in which 5% by weight of palladium was supported on activated carbon was added to this solution, and hydrogenation was performed at a hydrogen pressure of 120 kg / cm ² G and a temperature of 120 ° C. Hydrogen absorption stopped at a reaction time of 4 hours, and the hydrogen absorption at this time was 97.2% of the theoretical hydrogen absorption. The activated carbon-supported palladium catalyst in the reaction solution was separated by filtration and the reaction product was analyzed with a UV meter. As a result, absorption of benzene nuclei was not observed, and it was confirmed that the hydrogenation reaction was complete. As a result of analysis by GLC, the purity of 3-methylcyclohexane-1,2,4-tricarboxylic acid trimethyl ester was 86.4%.
[0049]
Example 7
In the same autoclave as in Example 1, 25 g of benzene-1,2,4,5-tetracarboxylic dianhydride and 75 g of 1-propanol (Z = 2.7) were charged and esterified at a temperature of 220 ° C. for 1 hour. It was. 0.5 g of a catalyst in which 5% by weight of ruthenium was supported on activated carbon was added to this solution, and hydrogenation was performed at a hydrogen pressure of 100 kg / cm ² G and a temperature of 130 ° C. Hydrogen absorption stopped at a reaction time of 2.5 hours, and the hydrogen absorption at this time was 98.1% of the theoretical hydrogen absorption. The activated carbon-supported ruthenium catalyst in the reaction solution was filtered off and the reaction product was analyzed with a UV meter. As a result, no absorption of benzene nuclei was observed, and it was confirmed that the hydrogenation reaction was complete. As a result of analysis by GLC, the purity of cyclopropyl-1,2,4,5-tetracarboxylic acid tetrapropyl ester was 95.9%.
[0050]
Comparative Example 1
Hydrogenation was carried out under exactly the same conditions as in Example 1 except that the previous esterification step was not performed. As a result, the hydrogen absorption stopped at a reaction time of 7 hours, and the hydrogen absorption at that time was 68.9% of the theoretical hydrogen absorption. The activated carbon-supported ruthenium catalyst in the reaction solution was filtered off, and the reaction product was analyzed with a UV meter. Absorption of benzene nuclei was observed, and the nuclear hydrogenation rate was 73.5%. As a result of analysis by GLC, the purity of dicyclohexyl-3,3 ′, 4,4′-tetracarboxylic acid tetramethyl ester was 38.6%.
[0051]
Comparative Example 2
Esterification was performed in the same manner as in Example 1 except that a stabilized nickel catalyst was used as the hydrogenation catalyst, and then hydrogenated at 170 ° C. However, no hydrogen absorption was observed even at a reaction time of 7 hours, and the hydrogenation reaction did not proceed.
[0052]
【The invention's effect】
By applying the method of the present invention, an alicyclic polycarboxylic acid ester can be obtained with high purity and high yield under industrially advantageous conditions.
[Chemical 7]

[Chemical 8]

Claims (5)

The aromatic polycarboxylic acid represented by the general formula (1) or its acid anhydride and an aliphatic alcohol are heated in the absence of a catalyst to obtain aromatic polycarboxylic acid ester mixtures having different degrees of esterification (esterification step). Then, the aromatic polycarboxylic acid ester mixture is heated in the presence of a noble metal-based hydrogenation catalyst and an aliphatic alcohol to perform nuclear hydrogenation (hydrogenation step). The manufacturing method of alicyclic polycarboxylic acid ester.
HOOC-A-COOH (1)
[In formula, A shows the aromatic carboxylic acid residue represented by general formula (a) or general formula (b). ]

[Wherein, X represents a single bond, —CO—, —O—, —CH ₂ —, —CH (—CH ₃ ) — or —C (—CH ₃ ) ₂ —. ]

[Wherein, R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents a hydrogen atom, a methyl group or a carboxyl group. ]
R ⁵ OOC-B-COOR ⁵ (2)
[Wherein, B represents an alicyclic carboxylic acid residue represented by the general formula (c) or the general formula (d). R ⁵ represents an alkyl group. ]

[Wherein, X is as described in formula (a). R ⁵ represents an alkyl group. ]

[Wherein, R ⁶ , R ⁷ , R ⁸ and R ⁹ are the same or different and each represents a hydrogen atom, a methyl group or a group COOR ⁵ . R ⁵ represents an alkyl group. ]  Aromatic polycarboxylic acid ester is biphenyl-3,3 ′, 4,4′-tetracarboxylic acid alkyl ester, biphenyl ether-3,3 ′, 4,4′-tetracarboxylic acid alkyl ester, benzophenone-3,3 ', 4,4'-tetracarboxylic acid alkyl ester, biphenylmethane-3,3', 4,4'-tetracarboxylic acid alkyl ester, ethylidene-4,4'-bis (alkyl 1,2-benzenedicarboxylate) Propylidene-4,4′-bis (1,2-benzenedicarboxylic acid alkyl), phthalic acid alkyl ester, 1,2,4-benzenetricarboxylic acid alkyl ester, 1,2,3,4-benzenetetracarboxylic acid alkyl Ester, 1,2,4,5-benzenetetracarboxylic acid alkyl ester, benzenehexacarboxylic acid alkyl ester, 3-methylphthalic acid alkyl ester, 4-methylphthalic acid alkyl ester, 3, 4,5,6-tetramethylphthalic acid alkyl ester, 5-methylbenzene-1,2,4-tricarboxylic acid alkyl ester, 6-methylbenzene-1,2,4-tricarboxylic acid alkyl ester, 3-methylbenzene 1,2,4-tricarboxylic acid alkyl ester, 3-methylbenzene-1,2,4,5-tetracarboxylic acid alkyl ester, 3,6-dimethylbenzene-1,2,4,5-tetracarboxylic acid alkyl ester The method for producing an alicyclic polycarboxylic acid ester according to claim 1.   The method for producing an alicyclic polycarboxylic acid ester according to claim 1 or 2, wherein the aliphatic alcohol is a linear, branched or cyclic aliphatic alcohol having 1 to 6 carbon atoms.   The method for producing an alicyclic polycarboxylic acid ester according to any one of claims 1 to 3, wherein the noble metal-based hydrogenation catalyst is a ruthenium-based catalyst.   The method for producing an alicyclic polycarboxylic acid ester according to any one of claims 1 to 4, wherein the type of the aliphatic alcohol in the esterification step is the same as the type of the aliphatic alcohol in the hydrogenation step.