JPS6141904B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for purifying a carbonate compound having an ethylenically unsaturated group (hereinafter sometimes simply abbreviated as unsaturated carbonate). Note that the carbonate compound having an ethylenically unsaturated group in the present invention refers to a carbonate ester having at least one carbon-carbon double bond in the molecule. Various types of unsaturated carbonates are known, and because they have unsaturated groups, they are most commonly used as raw materials for obtaining polymers. For example, diethylene glycol bis(allyl carbonate) is a typical unsaturated carbonate compound.
Because its polymer has excellent transparency and high surface hardness, it is widely used in the optical field, especially for eyeglass lenses. In addition, various methods for synthesizing unsaturated carbonates are known, for example, JP-A-49-11832;
No. 49-110628, No. 52-60892, No. 53-12813,
US Pat. No. 2,648,697 and the like have been proposed. Therefore, unsaturated carbonate contains impurities originating from raw materials for its synthesis, coloring components produced as by-products during synthesis reactions, components that cause coloration during polymerization, and the like.
Therefore, it is necessary to remove these impurities.
However, if one attempts to carry out distillation purification all at once, the unsaturated carbonate has a high boiling point and is polymerizable, requiring complicated and advanced techniques, which is not industrially practical. Vacuum distillation can also be considered, but since it requires high temperatures, impurities decompose and there is a high possibility that impurities or decomposed components will be mixed into the distillate.
Particularly when unsaturated carbonate is used as a polymerization raw material, it is a big problem to remove colored components or components that cause coloring. The present inventors have conducted extensive research to obtain an unsaturated carbonate compound that does not contain any coloring components, and have found that the coloring components in the unsaturated carbonate can be easily removed by an inorganic adsorbent. The present invention has been based on the discovery that the removal efficiency increases when the unsaturated carbonate is present, and that by contacting it with an inorganic adsorbent after pretreatment with an oxidizing agent, the removal effect of the colored component increases without changing the unsaturated carbonate. I was able to complete it. That is, the present invention provides a method for purifying a carbonate compound, which comprises contacting a carbonate compound having an ethylenically unsaturated group with an inorganic adsorbent in the presence of a mineral acid. Further, the present invention provides that after treating a carbonate compound having an ethylenically unsaturated group with an oxidizing agent,
A method of purifying a carbonate compound by contacting it with an inorganic adsorbent is also provided. The carbonate compound having an ethylenically unsaturated group in the present invention is a carbonate ester having at least one carbon double bond in the molecule, as described above. However, the method for producing unsaturated carbonate in the present invention is not particularly limited, and may be any known method such as the method described above,
A method of reacting the alcohol, organic halide, alkali metal carbonate, and carbon dioxide gas simultaneously or sequentially in the presence of a catalyst, or any other method may be employed. Typical examples of carbonate compounds having ethylenically unsaturated groups that can be applied in the present invention include allyl carbonate groups.

[Formula] or meta-allylka -bonate group

It is a compound with the formula: More specific examples include diallyl carbonate, dimethallyl carbonate, allyl methyl carbonate, allyl ethyl carbonate, allyl benzyl carbonate, ethylene glycol bis (allyl carbonate), propylene glycol bis (allyl carbonate), diethylene glycol bis (allyl carbonate),
Xylylene glycol bis(allyl carbonate) and the like are most widely used. The inorganic adsorbent used in the present invention is not particularly limited, and commonly used adsorbents can be used. Specifically, those preferably used include activated carbon, zeolite, activated alumina, activated clay, acid clay, diatomaceous earth, and the like. Among these adsorbents, activated carbon is particularly effective. The reason for this is unknown, but one reason is thought to be that activated carbon is hydrophobic, whereas general inorganic adsorbents are hydrophilic. Note that since the main purpose of the present invention is to remove decolorizing components or components that cause coloring in unsaturated carbonates, it is undesirable for color to come out from the inorganic adsorbent during the contact treatment. Therefore, in the present invention, it is preferable to use a synthesized adsorbent or a sufficiently purified adsorbent rather than a natural product. In the present invention, the unsaturated carbonate and the inorganic adsorbent are brought into contact with each other by a method generally used for adsorption in a liquid phase. Generally, a method in which an adsorbent is added to unsaturated carbonate to adsorb impurities and then filtered out, or a method in which unsaturated carbonate is passed through a column packed with an adsorbent are preferably employed. The method of using the inorganic adsorbent in the present invention varies depending on the means of contact between the unsaturated carbonate and the inorganic adsorbent, the conditions during the contact, the adsorption capacity of the inorganic adsorbent, etc., and cannot be absolutely limited. Generally, when a powdered inorganic adsorbent is used for the unsaturated carbonate, it is generally 0.5 to 0.5 to
It is preferable to use 3 (wt%) or more. Further, when using a column packed with an adsorbent, the packing may be determined in advance based on the chemical industry according to the required size of the column. In the present invention, heating at the time of contact between the unsaturated carbonate and the inorganic adsorbent is preferably employed because the effect is achieved by shortening the contact time. However, if the temperature is too high, polymerization of the unsaturated carbonate tends to occur and the adsorption effect decreases, so it is generally preferred to conduct the reaction at a temperature of 60 to 120°C, preferably 70 to 100°C. Furthermore, when carrying out heating, it is often effective and desirable to carry out the process under an inert gas atmosphere. Furthermore, in the present invention, the purification effect can be significantly improved by bringing the unsaturated carbonate into contact with the inorganic adsorbent in the presence of a mineral acid. The mineral acid used is not particularly limited, but sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, etc. are generally suitable.
In particular, those that are compatible with unsaturated carbonates such as concentrated sulfuric acid and phosphoric acid, and those that are nonvolatile, give particularly favorable results. Further, the amount of mineral acid used varies depending on the type of mineral acid, the type of inorganic adsorbent used, etc., and cannot be determined unconditionally. In general, it has the effect of removing coloring components of unsaturated carbonates or components that cause coloration within the range of 20 to 150% by weight based on the inorganic adsorbent, and most of the mineral acids are adsorbed by the inorganic adsorbent. Because of this, the unsaturated carbonate compound is not damaged and post-treatment is easy. Furthermore, in the present invention, the purification effect can be further significantly improved by treating the unsaturated carbonate with an oxidizing agent before contacting it with the inorganic adsorbent. The mechanism of action of the above oxidizing agent is not clear, but it is thought that the unsaturated carbonate molecules remain unchanged, and only impurities are oxidized, making them colorless or easily adsorbed to the next inorganic adsorbent. It can be done. The oxidizing agent used is not particularly limited, but concentrated sulfuric acid, hydrogen peroxide, sodium hypochlorite, bleaching solution, potassium permanganate, oxygen, etc. are generally suitable. Also, the amount of oxidizing agent used,
Since the conditions for oxidation treatment largely depend on the shape, oxidizing power, etc. of the oxidizing agent used, it is desirable to find optimal conditions for each case. When the oxidizing agent is in liquid form, the oxidizing agent is added to the unsaturated carbonate and mixed and stirred. Further, heating may be performed if necessary. Furthermore, when the oxidizing agent is uniformly mixed with the unsaturated carbonate, such as concentrated sulfuric acid, it is desirable to use a small amount of the oxidizing agent, generally 0.3% of the unsaturated carbonate.
~5% by weight is suitable. When the oxidizing agent does not mix uniformly with the unsaturated carbonate, such as in an aqueous solution of sodium hypochlorite, it is desirable to use a large amount of the oxidizing agent. against carbonate
0.5-10% by weight is commonly used. On the other hand, when the oxidizing agent is gaseous, it is preferably blown into the crude unsaturated carbonate. When oxygen is used as an oxidizing agent, activation by ultraviolet irradiation or the like is more effective. The oxidized crude unsaturated carbonate is separated from the oxidizing agent, washed with water if necessary, and then brought into contact with an inorganic adsorbent for purification. Further, it is also a preferred embodiment to purify the unsaturated carbonate by repeating the method of the present invention twice or three times. The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples. In the examples, the degree of coloring was expressed by the APHA method (Hazen color number method). Further, the purity of the product was indicated by the purity determined by gas chromatography (GC purity). Reference example: Put 1.17 kg of soda ash (light ash), 2.30 kg of allyl chloride, and 64 g of triethylamine into an autoclave with a capacity of 10 and equipped with an electromagnetic stirrer, and pressurize carbon dioxide gas.
It was set to 20Kg/cm ² G. While stirring and maintaining the autograve internal pressure, add 0.53 kg of diethylene glycol to 27 kg.
It was dripped over several minutes. After the dropwise addition was completed, the mixture was left to stir for 30 minutes, and then the temperature was raised to 100° C. for 4 hours. After the reaction was completed, the reaction solution was cooled and taken out into a 20 glass flask, and about 15 cm of water was added to dissolve the solid matter. The organic layer was treated with a nitrogen gas valve to remove allyl chloride, washed with water, and steam distilled to strip low-boiling substances to obtain a crude product [diethylene glycol bis(allyl carbonate) with a GC purity of 97.3].
%] 1.03Kg was obtained. The coloring was done with APHA No. 300. Example 1 1 g of the inorganic adsorbent shown in Table 1 and mineral acid (reagent grade) were added to 50 g of the crude product of the reference example, and the mixture was stirred at 80° C. for 1 hour under a nitrogen gas atmosphere. After cooling, it was filtered using qualitative filter paper No. 5C (manufactured by Toyo Roshi Co., Ltd.). The results are shown in Table 1. In Table 1, Nos. 9 to 12 are all comparative examples, and No.
Nos. 9 and 10 show the results of treatment with only an inorganic adsorbent, and Nos. 11 and 12 show the results of treatment with only mineral acid.

[Table] Example 2 200 ml of 3% aqueous sodium hypochlorite solution was added to 170 g of the crude product of Reference Example, and the mixture was stirred at 30°C for 1 hour. Then, the mixture was washed with water for 3 days to obtain 161 g of an organic layer. Take 50g of the organic layer, add 1g of activated carbon (strong Shirasagi, manufactured by Takeda Pharmaceutical Co., Ltd.), and heat at 80°C under a nitrogen gas atmosphere.
The mixture was stirred for 1 hour. After cooling, it was filtered using qualitative filter paper No. 5C. As a result, it was number 20 on the APHA scale. In addition, 50 g of the organic layer after washing with water was taken, and Example 1
As a result of processing in the same manner as (Table 1 No. 1), AP
It was number 10 on the HA scale. Example 3 Same as Example 2, except that instead of the sodium hypochlorite aqueous solution in Example 2, 100 ml of a 35% hydrogen peroxide aqueous solution was used for 300 g of the crude product of the reference example, and the mixture was stirred at 80°C for 3 hours. Treated in the same way. As a result, the purified product obtained by treatment with activated carbon alone was number 15 on the APHA scale, and the purified product obtained by treatment with activated carbon and concentrated sulfuric acid was number 10 on the APHA scale. Example 4 Add 0.15 g of concentrated sulfuric acid to 50 g of the crude product of the reference example and
The mixture was stirred at ℃ for 1.5 hours. The coloring has become a little darker.
Next, 1 g of activated carbon (Refined Shirasagi: Takeda Pharmaceutical Co., Ltd.)
was added, and the treatment was then carried out in the same manner as in Example 1. As a result, it was number 15 on the APHA scale. Comparative Example 1 200 ml of a 3% aqueous sodium hypochlorite solution was added to 170 g of the crude product of the reference example, and the mixture was stirred at 30°C for 1 hour. After that, it was filtered in the same manner as in Example 1. As a result, the coloring was number 90 on the APHA scale. Comparative Example 2 100 ml of a 35% aqueous hydrogen peroxide solution was added to 300 g of the crude product of the Reference Example, and the mixture was filtered in the same manner as in Example 1, except that the mixture was stirred at 80° C. for 3 hours. As a result, the coloring
It was number 50 on the APHA scale. Example 5 50 g of the crude product of the reference example was irradiated with a 100 W ultraviolet lamp while air was valved for 2 hours. As a result, the coloring became a little darker. Activated carbon was added to the product thus obtained in the same manner as in Example 4, and the treatment was thereafter carried out in the same manner as in Example 4. As a result, it was number 20 on the APHA scale. Example 6 To 50 g of the purified product obtained in Table 1 No. 1 of Example 1, 1 g of activated carbon (Strong Shirasagi: manufactured by Takeda Pharmaceutical Co., Ltd.) and 0.15 g of sulfuric acid were added, and then treated in the same manner as in Example 1. I did some refining. As a result, the coloring was number 5 on the APHA scale. Example 7 2.4 moles of allyl chloroformate were added dropwise to a mixed solution of 3 moles of pyridine and 1 mole of diethylene glycol. During the dropping process, stir thoroughly and keep the temperature between -10 and -10.
It was kept in the 0°C range. After the reaction, the mixture was allowed to stand at room temperature for 3 hours, and then the reaction solution was decomposed with a 5% aqueous hydrochloric acid solution. The organic layer was separated, washed three times with water, and the crude product [GC purity of diethylene glycol bis(allyl carbonate)]
74.4%] 226g was obtained. (Coloring is on APHA scale.
It was number 400. ) 50 g of the crude product obtained as described above was purified in the same manner as in Example 1, Table 1, No. 1. As a result, the coloring was number 40 on the APHA scale. Example 8 A 3% aqueous sodium hypochlorite solution was added to 60 g of the APHA scale No. 400 crude product obtained in Example 7.
60ml was added and stirred at 30°C for 1 hour. (The coloring at this time was APHA scale number 100.) The product obtained by the above treatment was washed three times with water to obtain 54 g of an organic layer. 1 g of activated carbon (Strong Shirasagi, manufactured by Takeda Pharmaceutical Co., Ltd.) was added to this organic layer, and the treatment was then carried out in the same manner as in Example 1. The result is
It was number 30 on the APHA scale.

Claims (1)

[Scope of Claims] 1. A method for purifying a carbonate compound, which comprises bringing a carbonate compound having an ethylenically unsaturated group into contact with an inorganic adsorbent in the presence of a mineral acid. 2. A method for purifying a carbonate compound, which comprises treating a carbonate compound having an ethylenically unsaturated group with an oxidizing agent and then contacting the compound with an inorganic adsorbent.