JP2870151B2 - Process for producing 1,3-phenylenedioxydiacetic acid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to 1,1 useful as a monomer for producing a polymer.
The present invention relates to a method for producing 3-phenylenedioxydiacetic acid (hereinafter abbreviated as 1,3-PDDA).

(Prior Art) An aryloxy compound (for example, phenol, naphthol, etc.) corresponding to aryloxyacetic acid is heated together with monochloroacetic acid in an aqueous sodium hydroxide solution, and then the mixture is treated with hydrochloric acid to industrially convert aryloxyacetic acid. It is known to manufacture. [Ullman; Encyclopedia of Industrial Chemistry, 4th Edition, Vol. 9, p. 578 (1975)]. Also,
For 1,3-PDDA, it has been reported that resorcinol and monochloroacetic acid can be synthesized by heating and stirring in an aqueous sodium hydroxide solution (N.Yoda et.al., Makromol.Chem., 32 ,
1, (1959); Shigeru Tsutsumi et al., The Chemical Journal of Japan, 81 , 1167, (1960)
Year)〕.

(Problems to be Solved by the Invention) However, in the conventional technique, hydrolysis of monochloroacetic acid by alkali is remarkably concomitant, and even if excess monochloroacetic acid is used, the yield of the target 1,3-PDDA can be increased. Is generally difficult. According to Tsutsumi et al., The yield of 1,3-PDDA is about 55%. In order to improve this point, the use of DMSO as a reaction solvent has been proposed, but the process is complicated, there is a problem in cost, the reproducibility is poor, and satisfactory results have not been obtained. (GSKazakova.et.al., Osno
vn.Org.Sint.Nettekhim., 16 , 26-8, (1982)].

(Means for Solving the Problems) In view of the above-mentioned circumstances, the present inventors have found that when reacting resorcinol and monochloroacetic acid to produce 1,3-PDDA, the decomposition and side reactions of monochloroacetic acid are suppressed, and As a result of various studies to obtain a method capable of recovering 1,3-PDDA in a high yield, a specific reaction method was adopted and the reaction was carried out while maintaining the pH in the reaction system within a specific range. It has been found that the object of the invention is achieved.

That is, the gist of the present invention is to react resorcinol and monochloroacetic acid in an alkaline aqueous solution, and to produce 1,3-PDDA, use an aqueous solution containing an alkaline salt of resorcinol as a bedding solution and supply monochloroacetic acid thereto. And producing the 1,3-PDDA, wherein the reaction is carried out by supplying an aqueous alkali solution and maintaining the pH in the reaction system within the range of 8 to 11.

 Hereinafter, the present invention will be described in detail.

In the present invention, an aqueous solution containing an alkali salt of resorcinol is used as a bedding solution.
It is a sodium salt or a potassium salt. This bedding solution is usually
For example, it can be easily prepared by uniformly mixing resorcin with an aqueous alkali solution such as an alkali hydroxide such as sodium hydroxide or potassium hydroxide or an alkali carbonate such as sodium carbonate or potassium carbonate. The concentration of resorcinol in the bedding solution is usually about 10 to 50% by weight.

Monochloroacetic acid is supplied to the above-mentioned bedding solution to carry out the reaction. The amount of monochloroacetic acid used is usually 2.1 to 3 times the molar amount of resorcinol. In the present invention, since the decomposition of monochloroacetic acid is small, it is not necessary to use a large amount of monochloroacetic acid. Therefore, the generation of by-products due to overreaction can be suppressed. The amount of 3-hydroxyacetate phenol that is a body increases. Monochloroacetic acid can be supplied intermittently or continuously.However, if the supply rate is too high, the decomposition of monochloroacetic acid and the accompanying side reaction occur, so that the unreacted raw material supplied into the reaction system is usually supplied. The concentration of monochloroacetic acid in the reaction solution is adjusted to be 10% by weight or less. The supply time of monochloroacetic acid at this time varies depending on reaction conditions and the like, but is generally about 1 to 10 hours.

In the present invention, according to the supply of monochloroacetic acid,
It is an essential requirement that the reaction be carried out while maintaining the pH in the reaction system in the range of 8 to 11, preferably 8.5 to 10 by supplying the aqueous alkali solution. That is, the supply of monochloroacetic acid lowers the pH in the system by itself, and furthermore, the pH in the reaction system gradually decreases because hydrochloric acid is by-produced as the reaction proceeds. This is intended to be adjusted to a certain range. When the pH in the reaction system is lower than the above range, the reaction does not proceed satisfactorily and the desired 1,3-PDDA cannot be obtained in high yield, and conversely, when the pH is higher than the above range. In this case, hydrolysis of chloroacetic acid becomes severe, and the generation of by-products due to overreaction increases. In addition, as the alkaline aqueous solution used here, those similar to those used for the above-mentioned bedding solution may be mentioned, and the concentration of the aqueous solution is usually 10 to 50.
% By weight. The supply of the alkaline aqueous solution can be usually performed intermittently or continuously while measuring the pH in the reaction system.

The reaction temperature in the present invention is usually 40 to 100 ° C, preferably 50 to 95 ° C. If the reaction temperature is too low, the reaction rate is too slow to obtain the desired product, while if it is too high, the amount of by-products increases. The reaction time depends on the reaction temperature and the method of supplying monochloroacetic acid,
Usually, it is 0.5 to 10 hours, preferably 1 to 7 hours after the completion of the supply of monochloroacetic acid.

In order to carry out the reaction of the present invention, usually, a reactor is charged with an aqueous solution containing a predetermined amount of an alkali salt of resorcinol, and while heating and stirring the mixture to the reaction temperature, monochloroacetic acid and the aqueous alkali solution are introduced into the reaction system. While maintaining the pH of the solution constant. At this time, it is preferable that the monochloroacetic acid and the aqueous alkali solution are separately dropped, but in some cases, they may be mixed and dropped immediately before.

The mixture after the completion of the reaction was alkaline and produced 1,
Since 3-PDDA is also present as an alkali salt, it is acidified and recovered in the form of a free acid according to a conventional method. For example,
By adding an acid such as hydrochloric acid or sulfuric acid to the reaction mixture and adjusting the pH in the system to 3 or less, 1,3-PDDA crystals can be obtained. Depending on the alkali salt concentration of resorcinol at the time of the above reaction, there may be a case where 1,3-PDDA dialkali salt crystals are precipitated in the reaction mixture.In such a case, an acid is added to the reaction mixture. 1,3- by acidification
PDDA crystals can be obtained. Then, the 1,3-PDDA crystals are separated from the reaction mixture, and then recovered by water recrystallization and / or water washing as necessary.

(Examples) The method of the present invention will be described more specifically below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

EXAMPLES 1-3 AND COMPARATIVE EXAMPLE 1 A jacketed separable flask (manufactured by Pyrex) equipped with a composite electrode, a cooling tube, a thermometer and a stirrer and having a capacity of 2.5 liters was charged with 125 ml of demineralized water and 165.2 g of resorcinol (1.500 mol).
l) into the jacket while stirring under a nitrogen atmosphere, and warm the jacket to 70 ° C. After dissolution, a 47% aqueous solution of caustic soda was added by a pump to adjust the pH to 9.30 to prepare an aqueous solution containing the sodium salt of resorcinol. . Followed by 47% at 70 ° C
An aqueous solution of caustic soda was added by a pump, and while controlling the pH to 9.30 ± 0.10, 605.8 g of an aqueous monochloroacetic acid solution (containing 378.9 g (4.001 mol) of monochloroacetic acid) was added dropwise by a pump over 5 hours. The reaction was continued while controlling the pH at 9.30 ± 0.1 by adding 47% caustic soda at the same temperature for 2 hours.

After the crystals precipitated during the reaction were dissolved by adding water to homogenize the reaction solution, the results of analysis were shown in Table 1.

Examples 2 to 4 The reaction was carried out in the same manner as in Example 1 except for the pH and temperature described in Table 1. The results are shown in Table 1.

Comparative Example 1 In the method of Example 1, monochloroacetic acid was used as a bedding solution, caustic soda was added thereto to adjust the pH of the system to 9.3, and then an aqueous solution of resorcinol was used as a dropping solution. Table 1 shows the results when the reaction was carried out under the same conditions as in the above.

Comparative Example 2 A reaction was carried out in the same manner as in Example 1, except for the pH described in Table 1. The results are shown in Table 1.

Comparative Example 3 508 g of a 47% aqueous solution of caustic soda added to control the pH in Example 1 was previously added to a resorcinol salt aqueous solution, and then a monochloroacetic acid aqueous solution was added.
When the pH reached 9.3, the supply of a 47% aqueous sodium hydroxide solution was started, and the reaction was carried out in the same manner as in Example 1 except that the pH was kept at 9.3. The results are shown in Table 1.

(Effects of the Invention) According to the present invention, the decomposition of monochloroacetic acid is suppressed by adopting a specific reaction system in which resorcinol is used as a bedding solution and monochloroacetic acid is supplied thereto, and the target is obtained in high yield. , 3-PDDA can be obtained. This is achieved together with maintaining the pH in the reaction system in a narrow range of 8 to 11. Further, in the present invention, since the decomposition of monochloroacetic acid is small and the by-products due to overreaction are small, it is possible to carry out the reaction at a relatively high temperature, and as a result, the reaction time may be short. There is also. Furthermore, the purity of the obtained 1,3-PDDA crystal is high, and a high-quality crystal without coloring can be obtained.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-204833 (JP, A) JP-A-3-38544 (JP, A) JP-A 64-3146 (JP, A) JP-A 59-1984 95237 (JP, A) JP 27-1113 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB name) C07C 51/00-66/02

Claims (1)

(57) [Claims] An aqueous solution containing an alkali salt of resorcinol is used as a solution for producing 1,3-phenylenedioxydiacetic acid by reacting resorcinol and monochloroacetic acid in an alkaline aqueous solution. , And the reaction is carried out by supplying an aqueous alkali solution and maintaining the pH in the reaction system within a range of 8 to 11, thereby producing 1,3-phenylenedioxydiacetic acid.