JPS63227544A - Production of carboxylic acids - Google Patents

Abstract

NEW MATERIAL:Dicyclopentanetetracarboxylic acid expressed by formula I. USE:A raw material for various resins, such as polyimide, polyester, polyamide and epoxy resins, plasticizers and resin modifying agents. PREPARATION:An adduct of maleic anhydride with dicyclopentadiene (a compound expressed by formula II) or the corresponding hydrous acid obtained by hydrolysis in the presence of water or both are subjected to oxidative cleavage with hydrogen peroxide in the presence of one or two or more catalysts selected from the group consisting of tungstic acid, molybdic acid and heteropoly acids thereof to afford the aimed dicyclopentanetetracarboxylic acid compound formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing dicyclopentanetetracarboxylic acid.

The carboxylic acid is a compound useful as a raw material for various resins such as polyimide, polyester, polyamide, and epoxy, a raw material for a plasticizer, and a raw material for a resin modifier.

[Prior Art] As a result of various studies on the method of producing the corresponding carboxylic acid by oxidative cleavage of the Diels-Alder reaction product of maleic anhydride and dienes, the present inventors found that tungstic acid, molybdic acid and We have established and already proposed an industrially excellent method characterized by oxidative cleavage with hydrogen peroxide using one or more selected from these heteropolyacids as a catalyst (Japanese Patent Laid-Open No. 62-30737). ).

[Problems to be solved by the invention] In the course of subsequent studies, we similarly conducted oxidative cleavage of an adduct of maleic anhydride and dicyclopentadiene, and found that a novel oil-soluble polycyclic polycyclic polycyclic compound, which has not been described in any literature, was discovered. It has been found that carboxylic acids can be produced extremely efficiently.

That is, an object of the present invention is to provide a novel method for producing a polycyclic polycarboxylic acid.

[Means for Solving the Problems] The present invention provides an adduct of maleic anhydride and dicyclopentadiene, and/or a hydroxide of the adduct, in the group consisting of tungstic acid, molybdic acid, and their heteropolyacids. It is characterized by producing dicyclopentanetetracarboxylic acid represented by the following structural formula (I>) by oxidative cleavage with hydrogen peroxide in the presence of one or more catalysts selected from the following.

The adduct of maleic anhydride and dicyclopentadiene, which is a raw material for polycarboxylic acid in the present invention, is a compound obtained by mixing and heating the two, and has the following structural formula (n
).

The adducts are readily hydrolyzed in the presence of water to convert to the corresponding hydric acids, which also behave similarly to the anhydrides in the oxidation reactions of the present invention. Therefore, in the present invention, any of the anhydride, its hydric acid, or a mixture thereof can be used as a raw material (hereinafter, these are collectively referred to as "substrate").

Examples of the catalyst according to the present invention include tungstic acid, molybdic acid, and heteropolyacids thereof. The heteropolyacid referred to herein is a condensed acid consisting of two or more types of oxyacids, and the polyacid atoms include tungsten and molybdenum, and the heteroatoms include the following various types. Heteroatoms in the heteropolyacid of tungstic acid include P, AS, S
r, 1'-i, co, Fe, B, V, Be, I, N1,
Qa etc. are exemplified. Specific examples of heteropolyacids of tungstic acid include the following structural formulas: H3[PW1204o], H3(ASW12040), H4(S!W18O49), H4[T! W18O49), Town (C0W12040), H5 (FeW12040), +15 (BW1204Q), H3 [VW1204o], H6 (BeW9031), H6 (TeW6024), H5 (■W6024], H4 (N! W6024H) 6), H3 (GaW6024H6 ), H6 (P2 W20O58), H6 (AS2 WIBO62), H7 [PW11033].

In addition, heteroatoms in the heteropolyacid of molybdic acid include P, AS, Si, Ge, Ti, Ce, Th, M
n, N i , Te, I, C01Cr.

Examples include Fe, Ga, etc. A specific example of a heteropolyacid of molybdic acid is the following structural formula, H3CP M O
12040), H3 (ASM○1204o), H4 (81MO1204o), H4C08MO12040), Town (T i Mo 1204g), HB (Ce M O12042), H8 [Ce M O12042), H7, (PMo1103g) ), H7( ASMO11039), HB (08M01103g), H6 (MnMog 032), Machi (NiM Og 032), H6 [Dinge M Oe O24), H5 (IMo6024), H3 (GOMO6024H6), H3 (Cr Mo6o24"6) ), Examples include those having H3 (FeM0602486), H3 (GaMO6024H6), H4 (N!Mo6o24H6), HB (P2 MOIBOB2), and H6 (A32 MOIBO62).

Furthermore, polyatoms containing two or more types of atoms, such as tungstomolybdophosphoric acid, tangesdopanatophosphoric acid, vanadomolybdophosphoric acid, tungstomolybdosilicic acid, tangesdopanatosilicic acid, vanadomolybdosilicic acid, etc. Mixed coordination heteropolyacids, such as H4PMoW1104o, H4PR0W11040, H4PVMO11040°H5PV2M010040, H3PM06W6040, etc. can also be used.

All of these heteropolyacids exemplified above are known.

From the viewpoint of ease of synthesis or availability, heteropolyacids containing P or Sl as a heteroatom are preferred, particularly 12-tungstophosphoric acid (H3PW1204o), 12-tungstophosphoric acid (H3PW1204o),
-Tungstosilicic acid (H3S! W18O49), 1
2-molybdophosphoric acid (H3PMO12040) and the like are more preferred.

Further, the tungstic acid, molybdic acid, or a heteropolyacid thereof used as the catalyst may be a hydrate, and further, a compound capable of producing the tungstic acid, molybdic acid, or a heteropolyacid thereof in the reaction system. It may be in the form of Examples of such compounds include salts of alkali metals such as potassium and sodium, heavy metal salts such as cobalt, nickel, manganese, and copper, and ammonium salts. MS3 (M=W or M
It may be in the form of an oxide, chloride, or sulfide represented by C).

When using such salts, oxides, chlorides, and sulfides, it is possible to add a mineral acid such as phosphoric acid, hydrochloric acid, or sulfuric acid to the reaction system and conduct the reaction under acidic conditions with a pH of 4 or less. preferable.

Furthermore, it is advantageous to use the catalyst in the form of an acid, since there is no need to remove ammonium or metal ions in the separation operation. At this time, there is no problem even if mineral acids such as phosphoric acid, hydrochloric acid, sulfuric acid, perchloric acid, etc. coexist.

The catalysts exemplified above may be used alone or in combination of two or more.

In terms of reactivity, heteropolyacids are preferred, and in terms of balance between reactivity and cost, tungstic acid is preferred.

The manufacturing method according to the present invention is generally carried out as follows. That is, predetermined amounts of the substrate and catalyst as raw materials are charged into a reactor, hydrogen peroxide is added, and the reaction is carried out in a solvent while being heated and stirred.

The concentration of the substrate during the reaction is not particularly limited and can be selected from a wide range. However, from the viewpoint of reaction operability and productivity, the substrate concentration is preferably about 2 to 70% by weight, more preferably 30 to 50% by weight.

The amount of catalyst to be used is selected from a wide range as long as it is an effective amount to exhibit catalytic activity. However, from the viewpoint of reaction rate and catalyst cost, in terms of free acid (tungstic acid, molybdic acid, or their heteropoly M),
About 1 to 30% by weight of O,O' to the substrate, preferably 1%
A content of the order of ~10% by weight is advantageous.

The stoichiometric amount of hydrogen peroxide required for this reaction is 4 moles per mole of substrate, but in reality it is desirable to use a 10 to 50% excess. The concentration of hydrogen peroxide in the reaction mixture can be selected from a wide range. The lower limit is the concentration sufficient for the catalyst that has oxidized the substrate to recover its oxidizing ability with hydrogen peroxide, and even if the catalyst is quite dilute, the oxidation reaction will proceed, although a decrease in the reaction rate is inevitable. .

Further, there is no particular upper limit, and the concentration may be quite high. However, from the viewpoint of improving the reaction rate and reducing production costs by using low concentration hydrogen peroxide, it is about 0.1 mmol/l to 12 mol/l, preferably 10 mmol/l to 8 mol. /l is advantageous. Hydrogen peroxide is usually supplied in the form of an aqueous solution.

Water is suitable as a reaction solvent. Water-miscible organic solvents, such as alcohols having 1 to 4 carbon atoms, and alcohols having 1 to 4 carbon atoms.
It is also possible to use the carboxylic acid No. 4, dioxane, tetrahydrofuran, dimethylformamide, etc. alone, or in combination with water within a range that maintains a homogeneous phase.

The reaction temperature is usually 20 to 100°C from the viewpoint of reaction rate.
However, when the reaction is carried out under pressure, a reaction temperature of up to about 150'C can be employed. From the viewpoint of maintaining a realistic reaction rate and preventing or suppressing the decomposition of hydrogen peroxide, the range of 50 to 130'
It is preferable to carry out the reaction at about C.

The reaction time may vary depending on the water quality, the concentration of the catalyst and hydrogen peroxide, the reaction temperature, etc., but is usually about 1 to 24 hours.

[Example] The present invention will be described in detail below with reference to Examples.

(Manufacture of raw material tetracarboxylic dianhydride) Into a 51 stainless steel autoclave purged with nitrogen, 823 g of dicyclopentadiene, 588 tj of maleic anhydride = 11-acid, and 150 tj of xylene were charged.
'C for 3 hours. After the reaction, it was topped with xylene and distilled under reduced pressure. The obtained fraction is further rectified,
350 g of an adduct with a neutralization value of 436 (theoretical value 453) was obtained.

Example 1 The above adduct 46.
0g (0.2 mol), water 60g, tungstic acid 1.0
g, heat to 90℃ and reduce to 60% while stirring vigorously.
57 g of hydrogen peroxide solution was added dropwise, and the reaction was continued for 10 hours while maintaining the same temperature.

After the reaction was completed, the increase rate of free carboxyl groups calculated from the neutralization value of the reaction solution was 85%.

Incidentally, the increase rate of free carboxyl groups is a value calculated assuming that the difference between the neutralization value of the reaction mixture before addition of hydrogen peroxide and the neutralization value after the completion of the reaction is based on the carboxyl groups generated in the oxidation reaction. (the same applies hereafter).

Furthermore, it was confirmed by liquid chromatography internal standard method that dicyclopentanetetracarboxylic acid was produced at a yield of 82%. Note that no adducts of the raw materials were detected.

Example 2 The same operation as in Example 1 was performed, except that 5.0 g of molybdic acid and 5.0 g of phosphoric acid were used as catalysts.
The increase rate of free carboxyl groups was 80%, and dicyclopentanetetracarboxylic acid was obtained in a yield of 75%.

Example 3 The same operation as in Example 1 was performed except that 12-tungstophosphoric acid (H3PW12040-29H20>1.0'i) was used as a catalyst. As a result, the increase rate of free carboxyl groups was 88%, and dicyclo Pentanetetracarboxylic acid was obtained with a yield of 85%.

Example 4 Example 3 except that 60 g of dioxane was used as the solvent.
As a result of carrying out the same operation as above, the increase rate of free carboxyl groups was 86%, and dicyclopentanetetracarboxylic acid was obtained in a yield of 82%.

13 Example 5 46.0 g (0.2 mol) of the adduct of the raw material and 60 g of water were heated under reflux for 2 hours with vigorous stirring to obtain a hydroacid.

Add 12-molybdophosphoric acid (H3PMo120
40-291-120) and 5.0 g of phosphoric acid were added thereto, and while maintaining the temperature at 90'C, 57 g of 60% hydrogen peroxide solution was added dropwise, followed by further reaction for 10 hours. As a result of analysis, the increase rate of free carboxyl groups was 82%, and the yield of dicyclopentanetetracarboxylic acid was 79%.

Example 6 The same operation as in Example 1 was performed except that 12-tungstosilicic acid (H3PW12040.29H20>6.0 g) was used as a catalyst. As a result, the increase rate of free carboxyl groups was 80%, and dicyclopentanetetra Carboxylic acid was obtained with a yield of 76%.

[Effects of the Invention] Since the production method according to the present invention uses hydrogen peroxide, it can be produced safely, inexpensively, and with good yield without using harmful metals.
Dicyclopentanetetracarboxylic acid, which is an industrially new carboxylic acid, can be produced.

(Margin below) = 15-

Claims (1)

[Claims] An adduct of maleic anhydride and dicyclopentadiene and/or a hydric acid of the adduct in the presence of one or more catalysts selected from the group consisting of tungstic acid, molybdic acid, and their heteropolyacids, A method for producing dicyclopentanetetracarboxylic acid, characterized by oxidative cleavage with hydrogen peroxide.