JPS5935383B2 - Method for producing fatty acid partial ester of polyhydric alcohol - Google Patents

Description

Detailed Description of the Invention The present invention relates to polyhydric alcohols having a neopentyl type skeleton, such as pentaerythritol, dipentaerythritol, trimethylolpropane, etc., and lower fatty acids having 1 to 5 carbon atoms, such as formic acid, acetic acid, propionic acid, This invention relates to a method for producing partial esters with butyric acid, valeric acid, etc., particularly partial esters with a high monoester content.

Partial esters of lower fatty acids of polyhydric alcohols (hereinafter simply referred to as polyhydric alcohols) having neopentyl-type skeletons are used as additives for synthetic resins such as vinyl chloride resins and polyolefin resins, and their main uses are antifogging. agents, antistatic agents, stabilizers, etc.

Furthermore, among the fatty acid partial esters of polyhydric alcohols, esters having a particularly high monoester content are particularly effective for these uses. Fatty acid partial esters of polyhydric alcohols, particularly partial esters with a high monoester content, are difficult to synthesize by general esterification reactions, and as the esterification progresses further, large amounts of diesters, triesters, etc. are produced as by-products.
Conventionally, a method for synthesizing a partial ester with a high monoester content is to first synthesize a complete ester of a polyhydric alcohol, then add the polyhydric alcohol to this, and perform alcoholysis in the presence of a catalyst.

However, this known method cannot be called an industrial method because the reaction is in two stages and an operation for removing the catalyst is required. The present inventor has conducted intensive research on a method for producing fatty acid partial esters of polyhydric alcohols, especially partial esters with a high monoester content, in an industrially advantageous manner, unlike the above conventional methods. When at least 10% water by weight based on the total amount of polyhydric alcohol and lower fatty acid coexists during the reaction, the desired fatty acid partial ester of a polyhydric alcohol with a high monoethyl content can be synthesized in a good yield. They discovered this and completed the present invention.

Generally, the coexistence of water in an esterification reaction is highly discouraged, and in order to ensure a smooth reaction, steps are taken to expel the water produced by the reaction out of the reaction system. The present invention is significantly different from conventional esterification reactions in that the desired partial ester can be obtained by carrying out the reaction in the presence of water.

Furthermore, one of the desirable features of this reaction is that the desired partial ester composition can be easily obtained by changing the amount of fatty acid and water added to the polyhydric alcohol. .

As for the reaction temperature, a temperature (approximately 100 to 220° C.) for a normal esterification reaction of polyhydric alcohol and fatty acid is sufficient, and a temperature around the reflux temperature of water and fatty acid is particularly preferable.

An example of the relationship between the molar ratio of polyhydric alcohol and fatty acid is pentaerythritol (1 mol) and water (10 mol).
Add fatty acid (propionic acid) while fixing the amount (mole)
Figure 1 shows the results of examining the amount of unreacted pentaerythritol and the amount of pentaerythritol monopropionate produced when the amount of was varied from 1 mol to 10 mol and the reaction was carried out at reflux temperature for 5 hours.

In the figure, . . . O . From the results shown in FIG. 1, in order to obtain a monoester content of 50% or more, the appropriate amount of fatty acid is 3 to 7 times the mole of the polyhydric alcohol.

Of course, the composition of the product varies considerably depending on the amount of water added, reaction time, reaction temperature, type of polyhydric alcohol, etc. Generally, if the amount of water added is 10% by weight or less based on the total weight of polyhydric alcohol and fatty acid, the monoester content will be extremely low, and more diesters will be produced than monoesters. For example, for 1 mole of pentaerythritol and 3 moles of acetic acid, the amount of water added is 10%.
Figure 2 shows the results of examining the monoester and diester contents after removing unreacted pentaerystotol from the reaction mixture obtained by heating and reacting at 100°C for 5 hours. show. In FIG. 2, -Δ-Δ1 indicates pentaerythritol monoacetate, and -0-0- indicates pentaerythritol diacetate. The amount of water present in this reaction must be appropriately selected depending on the reaction time and the desired composition of the partial ester, but is preferably 10 to 70% by weight based on the total amount of polyhydric alcohol and fatty acid.

Note that there is no problem in adding a conventional esterification catalyst or solvent to the reaction system when carrying out this reaction, but the reaction time tends to be shortened. Next, the present invention will be explained by examples, but the present invention is not limited thereto.

Example 1 1 mole of dipentaerythritol (2547), 5 moles of acetic acid (300y) and 15 moles of water (2707) were mixed and stirred and refluxed at 103°C for 15 hours, and then water and unreacted acetic acid were removed under reduced pressure. (90m77!Hg, 60-90°C), and the resulting mixture of dipentaerythritol acetate was quantified using gas chromatography.

The results are shown in Table 1. The composition shown in Table 2 was obtained by dissolving the above composition in a benzene-ethanol mixed solvent and removing insoluble dipentaerythritol.

Example 2 1 mole (136y) of pentaerythritol, 2.5 moles (1857) of propionic acid, and 10 moles (180y) of water were mixed and stirred, and the mixture was reacted at 180°C for 1 hour. After that, water and unreacted propionic acid were mixed and stirred. Under reduced pressure (80mmHg, 60~
80° C.), and the resulting mixture of pentaerythritol propionate esters was quantitatively determined using gas chromatography.

The results are shown in Table 3. Table 4 The composition shown in Table 4 was obtained by dissolving the above composition in toluene and filtering out insoluble pentaerythritol to remove the toluene.

Table Example 3 1 mol (134y) of trimethylolpropane, 3 mol (2227) of propionic acid, and 10 mol (180 t) of water were mixed and stirred, refluxed at 110°C for 12 hours, and then -
Water and unreacted puropionic acid were removed under reduced pressure (100 mmHg).
, 80° C.), and the resulting mixture of propionic acid esters of trimethylolpropane was quantitatively determined using gas chromatography.

The results are shown in Table 5. Table 5 When the above composition was filtered to remove trimethylolproban at room temperature, the composition shown in Table 6 was obtained.

Table Example 4 1 mol (136V) of pentaerythritol and 1.1 acetic acid
Mol (667) and 11.1 mole of water (2007) were mixed and stirred and refluxed at 100°C for 18 hours. After that, water and unreacted acetic acid were mixed under reduced pressure (100 mmHg, 60-80°C).
), and the resulting mixture of pentaerythritol acetate was quantitatively determined using gas chromatography.

The results are shown in Table 7.

Table 7 When the above composition was filtered to remove pentaerythritol at room temperature, the composition shown in Table 8 was obtained.

Table 8 As shown in the results of Examples 1 to 4, partial esters with a high monoester content were obtained in all cases.

In Examples 1 to 4, the reaction time is relatively long, from 12 hours to 20 hours, but as shown in the examples below, the reaction time can be significantly shortened by changing the fatty acid and water contents. can do. Example 5 1 mol of dipentaerythritol (2547), 28 mol of acetic acid (16807) and 40 mol of water (720 t) were mixed and stirred, and the mixture was heated at 103°C for 1 mol.
After refluxing for a period of time, water and unreacted acetic acid were removed under reduced pressure (100 mm
The mixture of dipentaerythritol acetate obtained was quantitatively determined using gas chromatography.

The results are shown in Table 9. Dissolve the above composition in a benzene-ethanol mixed solvent,
After removing the insoluble dipentaerythritol, the composition shown in Table 10 was obtained.

Table Example 6 1 mole (136y) of pentaerythritol, 6 moles (360t) of acetic acid, and 12 moles (216y) of water are mixed and stirred, refluxed at 103°C for 1 hour, and then water and unreacted acetic acid are removed under reduced pressure. The resulting mixture of pentaerythritol acetate was quantified using gas chromatography to obtain the compositions shown in Table 11.

Person 11 Dissolve the above composition in a benzene-ethanol mixed solvent,
Insoluble pentaerythritol was removed to obtain the composition shown in Table 12.

The influence of the catalyst and solvent will be shown in Examples 7 and 8 below, and it will be understood that the reaction time is significantly shortened both when a catalyst is added and when a solvent is added.

Example 7 0.57 of potassium carbonate was added as a catalyst to a mixture of pentaerythritol acetic acid and water having the composition ratio shown in Example 6, and the reaction was carried out at 100°C. As a result, a mixture with a high monoester content was obtained in 4 hours. An ester was obtained.

When unreacted pentaerythritol was removed, the composition shown in Table 13 was obtained. Table 13 Example 8 1 mole of trimethylolpropane (134f) and 3 valeric acid
Toluene 4007 was added as a solvent to mol (3067) and 8 mol of water (144 V), mixed and stirred, and the reaction was carried out at 115°C for 3 hours. After that, water and unreacted valeric acid were mixed under reduced pressure (6
01t71LHg, 90°C), the mixed ester shown in Table 14 was obtained.

Table 14 Reference Example 1 1 mol (254 t) of dipentaerythritol and 2 mol (60 t) of acetic acid were mixed and stirred and reacted at 100°C for 20 hours, after which unreacted acetic acid was removed under reduced pressure (100111!
The mixture of dipene erythritol acetate obtained by removal with UHg (60 to 70°C) was quantitatively determined using gas chromatography.

The results are shown in Table 15. Reference example 2 Pentaerythritol 1 mol (136V) and butyric acid 1.5
mol (132V) and stirred at 140°C for 20 hours, then unreacted butyric acid was removed under reduced pressure (100mmHg,
70 to 80° C.), and the resulting mixture of pentaerythritol butyrate was quantitatively determined using gas chromatography.

The results are shown in Table 16. Table 16 Reference Example 3 1 mol (134 t) of trimethylolproban and 1 mol (74 t) of propionic acid were mixed and stirred, and the mixture was heated at 120°C for 20
The reaction was carried out for a period of time, and then unreacted propionic acid was removed under reduced pressure (100 mTfLHg 160-80°C), and the resulting mixture of propionic acid esters of trimethylolpropane was quantitatively determined using gas chromatography.

The results are shown in Table 17.

As is clear from Table Reference Examples 1 to 3, the desired partial ester with a high monoester content cannot be obtained in a general esterification reaction without adding water.

[Brief explanation of the drawing]

Figure 1 shows the changes in the amount of unreacted pentaerythritol and the amount of pentaerythritol monopropionate produced depending on the amount of propionic acid used in the reaction of pentaerythritol and propionic acid in the presence of a certain amount of water. FIG. 2 is a curve diagram illustrating changes in the composition ratio of pentaerythritol monoacetate and diacetate in the product when pentaerythritol and acetic acid are reacted by changing the amount of water added. It is.

Claims (1)

[Scope of Claims] 1. When reacting a polyhydric alcohol having a neopentyl type skeleton with a fatty acid having 1 to 5 carbon atoms, a weight ratio of at least 1 based on the total amount of the polyhydric alcohol and the fatty acid.
A method for producing a fatty acid partial ester of a polyhydric alcohol, the main component of which is a fatty acid monoester of a polyhydric alcohol having a neopentyl-type skeleton, characterized in that the reaction is carried out by adding 0% water. 2. The manufacturing method according to claim 1, wherein water is added in an amount of 10 to 70% by weight based on the total amount of the polyhydric alcohol and the fatty acid.