JPH0251538B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing a tertiary carboxylic acid, and more specifically, a method for producing a tertiary carboxylic acid that prevents a decrease in the activity of a catalyst. [Prior art and its problems] Conventionally, in the presence of a sulfuric acid-cuprous oxide catalyst, 1-
A known method is to react an olefin such as hexene or 1-octene with carbon monoxide to produce a tertiary carboxylic acid such as 2,2-dimethylpentanoic acid. However, in the conventional production method, a tertiary carboxylic acid-sulfuric acid complex is produced in high yield because sulfuric acid is used at a high concentration, but it is difficult to extract this tertiary carboxylic acid-sulfuric acid complex. As a result, the yield of tertiary carboxylic acid was low, and a large amount of waste sulfuric acid was produced. [Means for Solving the Problems] The inventors have solved the problems described above, and have achieved high yield by easily separating the tertiary carboxylic acid-sulfuric acid complex without discharging a large amount of waste sulfuric acid. We have conducted intensive research into a method that can obtain tertiary carboxylic acid using a method that allows the recovered catalyst-containing liquid to be used as a catalyst again without reducing the yield of tertiary carboxylic acid. As a result, we arrived at this invention. That is, this invention extracts a product obtained by reacting olefin and carbon monoxide in the presence of a catalyst of 80 to 90% sulfuric acid and cuprous oxide without adding water. By doing so, the extract containing the tertiary carboxylic acid-sulfuric acid complex and the catalyst liquid are separated, and at least a stoichiometric amount of water of the tertiary carboxylic acid-sulfuric acid complex to be decomposed is added to the extract. This is a method for producing a tertiary carboxylic acid, characterized in that the recovered sulfuric acid obtained by this process and the catalyst liquid are recycled to the reaction system for reuse. Next, the method of the present invention will be explained with reference to the drawings. FIG. 1 is a flow diagram illustrating an example of the method of the present invention. In FIG. 1, 1 indicates a reaction vessel, and carbon monoxide is supplied from a first raw material supply pipe 2 connected to this reaction vessel 1, and olefin is supplied from a second raw material supply pipe 3 connected to this reaction vessel 1. The olefin and carbon monoxide are reacted in the reaction vessel 1 in the presence of a sulfuric acid-cuprous oxide catalyst. This reaction between the olefin and carbon monoxide is catalytic, and a tertiary carboxylic acid-sulfuric acid complex is immediately generated when the olefin and carbon monoxide come into contact in the reaction vessel 1. In this case, low concentration sulfuric acid is sufficient as the sulfuric acid used as a catalyst, and sulfuric acid with a concentration of 80 to 90% is preferable. The concentration of sulfuric acid is recorded.
This is because when it is 80 to 90%, it is possible to improve the separability of the produced carboxylic acid. Further, the reaction pressure is usually 0 to 100 kg/cm2, preferably 10 to 15 kg/cm2. This is because a reaction pressure of 10 to 15 kg/cm2 can prevent a decrease in the yield of carboxylic acid due to the use of sulfuric acid at a low concentration. The olefins used in the method of this invention include, for example, diisobutylene, 1-hexene, 2-hexene,
-hexene, 3-hexene, 1-heptene, 2-
Olefins having linear or branched chains such as heptene, 3-heptene, 1-octene, 2-octene, 3-octene, 4-octene, 1-nonene, 2-nonene, 3-nonene and 4-nonene, and cyclohexene , and cycloolefins such as cyclohexane substituted with an alkyl group such as a methyl group or an ethyl group. Furthermore, the olefin used in this invention may be a mixture of isomers. The reaction product liquid in the reaction vessel 1 is sent to the first separation tank 5 via the first transfer pipe 4, where it is mixed with the extraction agent supplied from the extraction supply pipe 6, and is mixed with the aqueous catalyst liquid and the oil layer. It is separated into extract liquid. The extracting agent supplied to the first separation tank 5 may be any solvent as long as it does not mix with water and dissolves the tertiary carboxylic acid-sulfuric acid complex that is the reaction product. For example, n-pentane, n
Examples include aliphatic hydrocarbons such as -hexane, n-heptane, and n-octane, and aromatic hydrocarbons such as benzene, toluene, and xylene. The extraction agent may be mixed with the reaction product liquid from the stage of transfer by the first transfer pipe 4 by connecting the extraction agent supply pipe 6 to the middle of the first transfer pipe 4. The extractant supply pipe 6 is connected to the first separation tank 5 and the first separation tank 5 is
The reaction product liquid may be mixed with the reaction product liquid in the reaction product. This extraction treatment using an extractant is preferably performed in an atmosphere of a gas that does not contain moisture, and more preferably in an atmosphere that does not contain moisture and in which cuprous oxide cannot be oxidized. This is because the catalyst liquid is returned to the reaction vessel 1 and reused, but if the atmosphere during the extraction process contains moisture, the concentration of the recovered sulfuric acid will decrease and the activity of the catalyst will decrease. bring about. Furthermore, if this extraction treatment is performed in an oxidizing atmosphere, monovalent copper ions in the catalyst are oxidized to divalent copper ions, resulting in a decrease in catalyst activity. This is because, as a result, when the catalyst is recycled, the yield of tertiary carboxylic acid will decrease. Therefore, the atmosphere may be, for example,
Inert gases such as argon, helium, and neon, and gases such as nitrogen, carbon dioxide, and carbon monoxide can be used. Among these various gases, carbon monoxide gas is particularly preferred. When carbon monoxide gas is used, even if oxygen is mixed in the first separation tank 5, the carbon monoxide is oxidized and oxidation of the cuprous oxide is prevented. This is because there is no need to newly install a new gas supply pipe in the separation tank 5, and it is sufficient to simply extend a branch pipe from the first raw material supply pipe 2 and connect it to the first separation tank 5. Furthermore, when tertiary carboxylic acid is produced by a batch method and the extraction process is carried out in a carbon monoxide atmosphere, this extraction process can be carried out in the reaction vessel 1. can be omitted to simplify the device. After being separated into an extract and a catalyst liquid in the first separation tank 5, the catalyst liquid is returned to the reaction vessel 1 through a recovery line 7, while the extract is transferred through a second transfer pipe 8. It is transferred to the second separation tank 9. In this second separation tank 9, the tertiary carboxylic acid-sulfuric acid complex in the extract is decomposed by water supplied from the water supply pipe 10, and an oil layer of the tertiary carboxylic acid and an aqueous layer containing sulfuric acid are formed. separated into In this case, the amount of water supplied may be at least the stoichiometric amount of the tertiary carboxylic acid-sulfuric acid complex to be decomposed. That is, since the tertiary carboxylic acid-sulfuric acid complex is decomposed by the amount of water required for the reaction, sulfuric acid can be recovered without reducing the concentration of the catalyst solution. The water may be supplied at the stage of transferring the extract by connecting the water supply pipe 10 to the middle of the second transfer pipe 8, or the water supply pipe 10 may be connected to the second separation tank 9. Connect this second separation tank 9
It may also be supplied inside. The oil layer separated in the second separation tank 9 contains a plurality of types of tertiary carboxylic acids depending on the raw material olefin. Transfer to 12. On the other hand, the aqueous layer separated in the second separation tank 9 is returned into the reaction vessel 1. In the distillation column 12, the oil layer is distilled and separated into an extractant and a tertiary carboxylic acid component as a product. The separated extractant is used again for extraction processing via the extractant supply pipe 6. In addition, if the tertiary carboxylic acid component contains multiple types of tertiary carboxylic acids, this tertiary carboxylic acid component is
It is further transferred to a rectification column and fractionated into each tertiary carboxylic acid. The catalyst liquid from the first separation tank 5 and the aqueous layer from the second separation tank 9 are mixed in the recovery line 7 to adjust the concentration of the cuprous sulfuric acid catalyst. It is preferable to keep it. For example, when the raw material is diisobutylene, the tertiary carboxylic acids obtained by the method of the present invention include 2,2,4,4-tetramethylpentanoic acid, 2,2,3,4-tetramethylpentanoic acid,
2-ethyl-2,3,3-trimethylbutanoic acid, and when the raw material is 1-hexane, 2,2
-dimethylpentanoic acid, 2-methyl-2-ethylbutanoic acid, 2,2-dimethylbutanoic acid, 2,2-
dimethylpropanoic acid, and when the raw material is 1-heptene, 2,2-dimethylhexanoic acid, 2
-methyl-2-ethylpentanoic acid, and when the raw material is 1-octene, 2,2-dimethylheptanoic acid, 2-methyl-2-ethylhexanoic acid,
2-methyl-2-propylpentanoic acid, and when the raw material is 2-octene, 2,2-dimethylheptanoic acid, 2-methyl-2-ethylhexanoic acid, 2-methyl-2-propylpentanoic acid Yes, and when the raw material is cyclohexane, it is 1-methylcyclopentanecarboxylic acid. The process of the invention can be carried out either batchwise or continuously. [Effects of the Invention] According to the present invention, the extract containing the tertiary carboxylic acid-sulfuric acid complex is washed with water to recover sulfuric acid, and the recovered sulfuric acid is recycled to the reaction system for reuse.
The sulfuric acid can be used effectively, and the problem of waste liquid treatment due to the discharge of a large amount of waste sulfuric acid can be solved. Furthermore, when the extraction treatment for obtaining the extract liquid is performed in an atmosphere in which cuprous oxide cannot be oxidized,
The catalyst liquid can be recovered without reducing the catalyst activity, and by returning the recovered sulfuric acid and the recovered catalyst liquid together to the reaction system as a catalyst, the catalyst can be used repeatedly, and the tertiary carboxylic acid can maintain a high yield. Furthermore, since the method of the present invention reuses the recovered sulfuric acid as a catalyst component, only a small amount of sulfuric acid is required as a catalyst to produce the tertiary carboxylic acid. Furthermore, since low-concentration sulfuric acid is used as a component of the catalyst, the tertiary carboxylic acid-sulfuric acid complex can be easily separated, which also makes it possible to produce tertiary carboxylic acid in high yield. be able to. [Examples] Next, the present invention will be explained in further detail by showing examples and comparative examples of the present invention. Examples 1 to 3 Catalysts containing sulfuric acid with the concentration and usage amount shown in Table 1 and cuprous oxide in the usage amount shown in Table 1 were charged into a reaction vessel, and the inside of the reaction vessel was sufficiently filled with carbon monoxide. After the substitution, the amount of carbon monoxide shown in Table 1 was absorbed while stirring. Next, while maintaining the carbon monoxide pressure at 15 kg/cm2, the olefin of the type shown in Table 1 was fed into this reaction vessel for 1.5 hours, and the olefin and carbon monoxide were combined under the reaction conditions shown in Table 1. reacted. Note that during the reaction, the amount of carbon monoxide used in the reaction and reduced was replenished. After 1.5 hours had passed, the supply of olefin was stopped, and the mixture was stirred for an additional hour.
The product liquid thus obtained was subjected to extraction treatment under the atmosphere shown in Table 1 by supplying extractants of the type and amount used as shown in Table 1 into the reaction vessel and stirring. After the extraction treatment, the extraction phase was separated from the catalyst phase, and the resulting extract was washed with water. The amount of water used at this time is calculated using the following formula. Amount of olefin used (mol) × Yield / 100 × 18 Next, the oil layer obtained by standing was distilled and the third
A mixture of grade carboxylic acids was obtained. Further, the catalyst liquid obtained by the extraction process and the aqueous layer obtained by the water washing process were collected together and repeatedly circulated and used in the reaction between olefin and carbon monoxide. Table 1 shows the number of times the catalyst was used repeatedly and the yield of tertiary carboxylic acid (total). Comparative Examples 1 to 3 The catalyst liquid obtained from the extraction process is collected and recycled repeatedly for use in the reaction between olefin and carbon monoxide, but the recovered sulfuric acid obtained from the water washing process is not recycled as a catalyst. The rest was the same as in the previous example. The results are shown in Table 1.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a process diagram as an example of implementing the method of the present invention. 1... Reaction container, 2... First raw material supply pipe,
3... Second raw material supply pipe, 4... First transfer pipe, 5... First separation tank, 6... Extractant supply pipe,
7...Recovery line, 8...Second transfer pipe, 9...
...Second separation tank, 10...Water supply pipe, 11...
Third transfer pipe, 12... distillation column.

Claims (1)

[Claims] 1. Extracting the product obtained by reacting olefin and carbon monoxide in the presence of a catalyst of sulfuric acid at a concentration of 80 to 90% and cuprous oxide without adding water. The treatment separates the extract into a tertiary carboxylic acid-sulfuric acid complex-containing extract and a catalyst solution, and adds at least a stoichiometric amount of water to the extract containing the tertiary carboxylic acid-sulfuric acid complex to be decomposed. A method for producing a tertiary carboxylic acid, which comprises recycling the recovered sulfuric acid obtained by adding the catalyst solution to the reaction system and reusing it. 2. The method for producing a tertiary carboxylic acid according to claim 1, wherein the extraction treatment is performed in an atmosphere in which cuprous oxide cannot be oxidized. 3. The method for producing a tertiary carboxylic acid according to claim 2, wherein the atmosphere in which the cuprous oxide cannot be oxidized is a carbon monoxide atmosphere.