JPH0615494B2 - Method for producing carboxylic acid - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a carboxylic acid, more specifically, a carboxylic acid utilizing a so-called Koch reaction in which an olefin is reacted with water in the presence of an acid catalyst. The present invention relates to a method for producing a carboxylic acid which is excellent in hydrolysis resistance and can be esterified into a carboxylic acid ester which can be suitably used in the fields of paints and solvents.

[Prior Art and its Problems] In the presence of an acid catalyst such as hydrochloric acid, sulfuric acid, phosphoric acid, or boron trifluoride, an olefin is reacted with carbon monoxide and water,
A method for producing a carboxylic acid having one more carbon number than the olefin as a raw material is known as Koch reaction.
Various methods for producing a carboxylic acid utilizing this Koch reaction have been conventionally proposed.

And, it is known that the reaction product obtained by the conventional method utilizing the Koch reaction is a mixture of carboxylic acids mainly containing a tertiary carboxylic acid [Japanese Patent Publication No. 48-35048].
JP-A-49-48616, R.I. Yoneda et al., Chemistry Letter, 1974, 607-610, Yoshie Soma et al., Oil Chemistry, No.
Vol. 30, No. 5, pp. 265-269 (1981), Yoshie Soma et al., Synthetic Organic Chemistry, Vol. 41, No. 6, pp. 561-569 (1983). ].

However, the carboxylic acid ester obtained by esterifying these reaction products cannot be said to have sufficient hydrolysis resistance, and is not necessarily suitable for use in the fields of paints and solvents, for example.

[Object of the Invention] An object of the present invention is to solve the above-mentioned problems, to provide a carboxylic acid ester which is excellent in hydrolysis resistance and can be suitably esterified into a carboxylic acid ester which can be suitably used in the fields of paints and solvents. It is to provide a method for producing an acid.

[Means for Achieving the Object] As a result of extensive studies conducted by the inventor to achieve the object, a specific olefin, carbon monoxide, and water were identified in the presence of a specific acid catalyst. When the reaction is carried out under the conditions described above, esterification is difficult due to its steric hindrance, and when esterified, a carboxylic acid which gives a stable esterified product having sufficient hydrolysis resistance can be obtained. They found out and arrived at this invention.

That is, the outline of the present invention is as follows: a catalyst consisting of sulfuric acid, a catalyst consisting of sulfuric acid and phosphoric acid, a catalyst consisting of boron trifluoride and water, a catalyst consisting of sulfuric acid, boron trifluoride and water, sulfuric acid, phosphoric acid, trifluoride. At least one selected from the group consisting of a catalyst consisting of boron fluoride and water and a catalyst consisting of phosphoric acid, boron trifluoride and water,
A carboxylate characterized in that an isobutylene oligomer, carbon monoxide and water are reacted under a pressure of ^{2 to} 40 kg / cm ² in the presence of a catalyst having an acid strength in the range of -9.2 to -6. It is a method for producing an acid.

The isobutylene oligomer has an isobutylene molecule,
For example, it is an oligomer formed by polymerizing about 2 to 12 in the presence of a Lewis acid catalyst such as hydrochloric acid, sulfuric acid, boron trifluoride, etc. In the usual case, an oligomer having a double bond at the terminal is synthesized. However, it also includes those in which unsaturated bonds are sequentially rearranged inside the molecule by the catalytic action and isomerized to internal olefins.

Preferred isobutylene oligomers can be represented, for example, by the following general formulas [I] and [II].

In the present invention, these isobutylene oligomers may be used alone or as a mixture of two or more kinds.

Particularly preferred isobutylene norigomers are isobutylene dimers and trimers. In the isobutylene dimer, 80% or more of 2,4,4-trimethylpentene-1 and 2,4,4-trimethylpentene-2 combined, and 2,3,
Diisobutylene mixtures containing 4-trimethylpentene-1 and 2,3,4-trimethylpentene-2 in a total amount of at least 5 to 15%, and isobutylene trimers, 2,4,4 , 6,6-pentamethyl-1-hexene and 2,4,
Triisobutylene mixtures containing 80% or more of branched C12 olefins such as 4,6,6-pentamethyl-2-hexene are preferred.

The carbon monoxide is preferably pure, but carbon monoxide-containing gas obtained from water gas, generator gas, coke oven gas, or the like can also be used.

The water is most preferably pure water, and distilled water, ion-exchanged water or the like can also be used.

The catalyst to be used in this invention is a catalyst composed of sulfuric acid, a catalyst composed of sulfuric acid and phosphoric acid, a catalyst composed of boron trifluoride and water, a catalyst composed of sulfuric acid, boron trifluoride and water, sulfuric acid and phosphoric acid. , At least one selected from the group consisting of a catalyst consisting of boron trifluoride and water and a catalyst consisting of phosphoric acid, boron trifluoride and water, and may further contain a metal oxide.

Preferable catalysts include, for example, sulfuric acid alone, a combination of sulfuric acid and phosphoric acid, a combination of sulfuric acid and boron trifluoride, a combination of phosphoric acid and boron trifluoride, etc. Is.

In the present invention, whichever catalyst is used, it is important that the catalyst used has an acid strength of -9.2 to -6 (preferably -9.0 to -6.5).

Here, the acid strength refers to Hammett's acidity function H ₀ .

If the acid strength of the catalyst used is greater than -6, the carbonylation reaction is less likely to occur, and the tendency for olehain polymerization and isomerization to occur increases. On the other hand, when it is smaller than -9.2, carbonylation is likely to occur while the isobutylene skeleton is retained, and the cleavage to isobutylene is severe, and a large amount of pivalic acid (C ₅ acid) is generated.

As the catalyst, for example, when a catalyst composed of a combination of sulfuric acid and phosphoric acid and having a value within the range of the acid strength is used, the sulfuric acid has a concentration of 30 to 30%.
It is 90% by weight, preferably 40-80% by weight.

Water contained in sulfuric acid and phosphoric acid or water added separately may be present in the mixture of sulfuric acid and phosphoric acid. The water content is usually 25% by weight or less.

For a catalyst consisting of a combination of sulfuric acid and boron trifluoride, a catalyst consisting of a combination of phosphoric acid and boron trifluoride,
The concentration of sulfuric acid, phosphoric acid or boron trifluoride in order to obtain a catalyst having a value within the range of the acid strength can be appropriately determined by experiments.

The method for preparing the catalyst is not particularly limited, and for example, sulfuric acid, phosphoric acid or boron trifluoride can be mixed in advance by a normal mixing operation to prepare a catalyst liquid containing sulfuric acid, phosphoric acid or boron trifluoride. When the catalyst is used, the catalyst solution may be used as it is, or may be diluted, and the metal oxide-containing catalyst solution may be added to the reaction system after adding and mixing the metal oxide to the catalyst solution. You may add.

Sulfuric acid, phosphoric acid or boron trifluoride and a metal oxide may be mixed and prepared in advance, and the catalyst solution containing the metal oxide may be used as described above.

Furthermore, to the mixture of isobutylene oligomer, carbon monoxide and water, which is a raw material, each component (catalyst component) which forms the catalyst in the present invention and, if necessary, each of the metal oxides are added simultaneously or sequentially. Good. When the catalyst components are added sequentially, the order of adding the catalyst components is not limited.

Further, the catalyst component may be added to the reaction vessel and the raw material may be added thereto.

In any case, when the isobutylene oligomer, carbon monoxide and water react, a catalyst consisting of sulfuric acid, a catalyst consisting of sulfuric acid and phosphoric acid, a catalyst consisting of boron trifluoride and water, sulfuric acid, boron trifluoride and At least one selected from the group consisting of a catalyst consisting of water, sulfuric acid, phosphoric acid, boron trifluoride and water and a catalyst consisting of phosphoric acid, boron trifluoride and water, and further a metal oxide if necessary. It suffices that the catalyst contained is in a state of being present.

Examples of the metal oxide include cuprous oxide, silver oxide, gold oxide and the like, and they can be used as a mixture with metallic copper or a divalent copper compound, but cuprous oxide is preferable. .

When the metal oxide, particularly cuprous oxide, is used as one component of the catalyst, the amount of the metal oxide used is such that the catalyst is composed of sulfuric acid, the catalyst is composed of sulfuric acid and phosphoric acid, boron trifluoride and water. Selected from the group consisting of a catalyst consisting of sulfuric acid, boron trifluoride and water, a catalyst consisting of sulfuric acid, phosphoric acid, boron trifluoride and water, and a catalyst consisting of phosphoric acid, boron trifluoride and water. 0.1 to 4% by weight, based on at least one weight,
It is preferably 0.2 to 2% by weight.

If the weight of this metal oxide is less than 0.1% by weight, the production of olefin polymerized oil tends to increase, and even if it exceeds 4% by weight, the reaction results do not show much improvement, but rather due to the production of water. The acid strength of the catalyst may increase and the carbonylation activity may decrease.

The amount of the catalyst used may be adjusted so that the catalyst contains at least 3 mol of sulfuric acid, boron trifluoride or sulfuric acid and boron trifluoride with respect to 1 mol of the olefin of the isobutylene oligomer.

In the method of the present invention, the reaction pressure (gauge pressure) is 2
-40 kg / cm ² , preferably 4-20 kg / cm ² .

If the reaction pressure exceeds 40 kg / cm ² , a large amount of carboxylic acid, such as 2,2,4,4-tetramethylpentanoic acid, which gives an esterified product having poor hydrolysis resistance, is produced. The reason for this is 40
Under relatively high pressure conditions exceeding kg / cm ² , the isobutylene oligomer maintains its skeleton and becomes 2,2,4,4-tetramethylpentanoic acid, while 2-40 kg / cm ² At relatively low pressure, the carbon skeleton of the isobutylene oligomer repeats a series of isomerizations to become chemically more stable than 2,2,4,4-tetramethylpentanoic acid, in other words, an inactive carboxylic acid. Seems to be. On the other hand, when the reaction pressure is lower than 2 kg / cm ² , polymerization of only the olefin may occur and the reaction may not proceed sufficiently.

The reaction temperature is usually 0 to 50 ° C. When the reaction temperature is lower than 0 ° C, the reaction temperature is lowered. On the other hand, if the temperature is higher than 50 ° C, sulfuric acid sludge and sulfuric acid ester will increase.

A reaction time of 45 to 120 minutes as a feeding time and 30 to 120 minutes as a stirring time is usually sufficient.

In the method of the present invention, the target product carboxylic acid is produced by the Koch reaction. For example, when diisobutylene is used as the raw material, the hydrolysis resistance when esterified is excellent, in other words, the ester. 2-ethyl-2,3,3-trimethylbutanoic acid, which is difficult to convert to; 2-isopropyl-2,3-dimethylbutanoic acid; 2,2,3,3-tetramethylpentanoic acid; 2,2,3,4-tetramethylpentanoic acid; And a mixture of other carboxylic acids is formed at the same time.
Further, the product is not limited to the tertiary carboxylic acid, and may contain a secondary carboxylic acid.

After completion of the reaction, aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, and n-octane; organic solvents such as aromatic hydrocarbons such as benzene, toluene, and xylene are used from the resulting reaction product solution. After extraction with water and washing with water to remove the extraction solvent, a carboxylic acid as a mixture containing a tertiary carboxylic acid as a main component can be obtained.

This carboxylic acid is a reaction product obtained by subjecting the carboxylic acid itself to a composition and subjecting the carboxylic acid to an esterification reaction (the main component is an ester mixture of carboxylic acids and contains a small amount of unreacted carboxylic acid). Can be used for various purposes. When the carboxylic acids in the carboxylic acid as a mixture are used for various purposes, the mixture of carboxylic acids may be subjected to a known separation / purification treatment to separate the carboxylic acids.

In the method of the present invention, the catalyst liquid can be recovered from the extraction solvent, and the recovered catalyst liquid can be circulated to the reaction system for reuse. When a metal oxide is used as one component of the catalyst, it is preferable to recover the catalyst solution in an atmosphere in which the metal oxide cannot be oxidized. When the catalyst solution is recovered under an oxidizing atmosphere, the metal oxide is oxidized to lower the catalytic activity, and the yield of carboxylic acid may decrease when the recovered catalyst is reused.

The carboxylic acid obtained by the method of the present invention is a carboxylic acid that gives an esterified product having excellent hydrolysis resistance,
For example, 2-ethyl-2,2,3-trimethylbutanoic acid, 2
-Isopropyl-2,3-dimethylbutanoic acid, 2,2,3,3-tetramethylpentanoic acid and 2,2,3,4-tetramethylpentanoic acid as a main component of the mixture, ester As a compound, it can be suitably used in the fields of paints and solvents.

EFFECTS OF THE INVENTION According to the present invention, (1) it is difficult to undergo esterification due to its own steric hindrance, and therefore a stable carboxylic acid having excellent hydrolysis resistance when esterified can be obtained. A wide range of applications, and (2) an industrially superior method for producing a carboxylic acid, which has the advantages that the catalyst can be effectively used if the catalyst solution is recovered and reused. Can be provided.

EXAMPLES Next, examples and comparative examples of the present invention will be shown to more specifically describe the present invention.

(Example 1) 150 ml of a catalyst consisting of an aqueous solution containing 85% by weight of sulfuric acid was charged into a reaction vessel, the inside of the reaction vessel was sufficiently replaced with carbon monoxide, and this was stirred until it became saturated. Absorbed carbon monoxide.

Next, maintain the reaction temperature at 25 ° C and increase the reaction pressure to 5
Diisobutylene 0.3 in the reaction vessel while maintaining kg / cm ^2.
Moles were supplied and the diisobutylene was reacted with carbon monoxide. The carbon monoxide consumed and reduced during the reaction was replenished so as to maintain a predetermined pressure.

After the reaction time of 1.5 hours had elapsed, the supply of diisobutylene was stopped, and stirring was continued for another 1 hour. Then, an equal amount of water was added.

The reaction mixture thus obtained was diluted 3-fold with water and then extracted with 200 ml of n-hexane three times.

Then, n-hexane was removed by distillation to obtain a carboxylic acid having the composition shown in Table 1.

The results are shown in Table 1.

The composition of the reaction product was measured by NMR spectrum.

(Examples 2 and 3) The procedure of Example 1 was repeated, except that the reaction pressure in Example 1 was changed to the pressure shown in Table 1.

The results are shown in Table 1.

(Example 4) In the above Example 1, except that a catalyst comprising an aqueous solution containing 64% by weight of sulfuric acid and 29% by weight of phosphoric acid was used in place of the catalyst comprising an aqueous solution of 85% by weight of sulfuric acid. It carried out similarly to 1.

The results are shown in Table 1.

(Examples 5 and 6) Example 5 was carried out in the same manner as Example 1 except that the reaction pressure was changed to the pressure shown in Table 1.

The results are shown in Table 1.

(Example 7) In Example 1, a catalyst made of an aqueous solution containing 66% by weight of sulfuric acid and 22% by weight of boron trifluoride was used in place of the catalyst made of an aqueous solution of 85% by weight of sulfuric acid, and the reaction temperature was set to 5 The same procedure as in Example 1 was carried out except that the temperature was changed to ° C.

The results are shown in Table 1.

(Examples 8 and 9) The same procedure as in Example 1 was performed except that the reaction pressure in Example 7 was changed to the pressure shown in Table 1.

The results are shown in Table 1.

(Example 10) In the above Example 1, 53% by weight of phosphoric acid and 37% of boron trifluoride were used instead of the catalyst consisting of an aqueous solution of 85% by weight of sulfuric acid.
The same procedure as in Example 1 was carried out except that a catalyst composed of an aqueous solution containing 50% by weight was used and the reaction temperature was 60 ° C.

The results are shown in Table 1.

(Examples 11 and 12) The same procedure as in Example 1 was carried out except that the reaction pressure in Example 10 was changed to the pressure shown in Table 1.

The results are shown in Table 1.

(Comparative Examples 1 and 2) Carboxylic acid was produced in the same manner as in Example 1 except that the reaction pressure in Example 1 was changed to the pressure shown in Table 1.

The results are shown in Table 1.

As is clear from Table 1, in each of the comparative examples, the formation of 2,2,4,4-tetramethylpentanoic acid, which is not sufficiently hydrolyzed when esterified, is higher than that in Example 1. There was a lot.

(Comparative Examples 3 and 4) Carboxylic acid was produced in the same manner as in Example 4 except that the reaction pressure in Example 4 was changed to the pressure shown in Table 1.

The results are shown in Table 1.

As is clear from Table 1, in each of the comparative examples, 2,2,4,4-tetramethylpentanoic acid which is not sufficiently hydrolyzed when esterified is produced, as compared with Example 4 described above. There was a lot.

(Comparative Examples 5 and 6) Carboxylic acid was produced in the same manner as in Example 7 except that the reaction pressure in Example 7 was changed to the pressure shown in Table 1.

The results are shown in Table 1.

As is clear from Table 1, in each of the comparative examples, the formation of 2,2,4,4-tetramethylpentanoic acid, which is not sufficiently hydrolyzed when esterified, is higher than that of Example 7. There was a lot.

(Comparative Examples 7 and 8) Carboxylic acid was produced in the same manner as in Example 10 except that the reaction pressure in Example 10 was changed to the pressure shown in Table 1.

The results are shown in Table 1.

As is clear from Table 1, in any of the comparative examples, 2,2,4,4-tetramethylpentanoic acid, which is not sufficiently hydrolyzed when esterified, is produced as compared with Example 10. There was a lot.

Comparative Example 9 In Example 10, 41% by weight of phosphoric acid and 51% by weight of boron trifluoride are contained in place of the catalyst composed of an aqueous solution containing 53% by weight of phosphoric acid and 37% by weight of boron trifluoride. A catalyst consisting of an aqueous solution is used and the reaction temperature is 5
A carboxylic acid was produced in the same manner as in Example 10 except that the reaction temperature was 75 ° C and the reaction pressure was 75 kg / cm ² .

The results are shown in Table 1.

As is clear from Table 1, in this comparative example, the amount of 2,2,4,4-tetramethylpentanoic acid formed, which is not sufficient in hydrolysis resistance when etherified, is higher than that in Example 10. There were many

(Example 13) 2,2,4,4-tetramethylpentanoic acid synthesized in the same manner as in Comparative Example 4 by using a catalyst composed of a mixed solution of sulfuric acid and phosphoric acid [carboxylic acid in the following and Table 1 It is referred to as (A). ] And 2-ethyl-2,3,3-trimethylbutanoic acid, 2-isopropyl-2,3-dimethylbutanoic acid, 2,2,3,3-tetramethylpentanoic acid, 2,2,3,4-tetra Mixtures of methylpentanoic acid and other tertiary carboxylic acids [below and in Table 1 carboxylic acid (B)
Called. ] [Carboxylic acid (A): carboxylic acid (B) = 53 mol%: 47 mol%] 50.0 g and methanol 2
00 ml was charged into a stainless steel 1 autoclave, and a methyl esterification reaction was carried out by stirring for 12 hours at a temperature of 225 ° C.

When the obtained product was subjected to gas chromatographic analysis, the conversion rate to methyl ester was 56%. Furthermore, when the unreacted acid was analyzed by gas chromatography, the ratio of the carboxylic acid (A) and the carboxylic acid (B) was changed to 17 mol%: 83 mol%.

From this, it was revealed that the carboxylic acid (B) had a significantly lower esterification reactivity than the carboxylic acid (A).

Example 14 A carboxylic acid mixture synthesized in the same manner as in Comparative Example 4 using a catalyst composed of a mixed solution of sulfuric acid and phosphoric acid [carboxylic acid (A): carboxylic acid (B) = 53 mol%: 47 mol %] 6.7 g and hexamethylphosphoric triamide 50 ml
Was placed in a three-necked flask having a volume of 100 ml, a 25% aqueous solution of caustic soda containing 2.43 g of caustic soda was added, and the mixture was stirred at room temperature for 30 minutes. Further, 10 g of methyl iodide was added. The liquid immediately became cloudy and sodium iodide was deposited.

The reaction solution was poured into 50 ml of water and extracted with ether. The extract was washed with water and then distilled to obtain 7.2 g of a methyl ester of a carboxylic acid mixture consisting of carboxylic acid (A) ester: carboxylic acid (B) ester = 53 mol%: 47 mol%.

Then, 1.2 ml of this methyl ester mixture was placed in a 500 ml flask, 400 ml of 0.1 N NaOH solution (water: ethylene glycol monomethyl ether = 1: 10 mixture) was added to it, and then left in a thermostat at 80 ° C for 50 hours. Then, alkaline hydrolysis was performed.

After that, when the reaction liquid was analyzed by gas chromatography, the ratio of the ester of carboxylic acid (A) and the ester of carboxylic acid (B) was 27 mol%: 78 mol%
It was revealed that the ester of carboxylic acid (A) is less susceptible to hydrolysis than the ester of carboxylic acid (B).

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location // C07B 61/00 300 C07C 67/00 8018-4H

Claims (1)

[Claims] 1. A catalyst comprising sulfuric acid, a catalyst comprising sulfuric acid and phosphoric acid, a catalyst comprising boron trifluoride and water, a catalyst comprising sulfuric acid, boron trifluoride and water, sulfuric acid, phosphoric acid, boron trifluoride and At least one selected from the group consisting of a catalyst composed of water and a catalyst composed of phosphoric acid, boron trifluoride and water, the acid strength of which is −
In the presence of a catalyst in the range of 9.2 to -6, isobutylene oligomer, carbon monoxide, and water are added at a pressure of ^{2 to} 40 kg / cm2.
A method for producing a carboxylic acid, which comprises reacting under the conditions of.