JPS5837291B2 - Acrylic San Mataha Methacrylic Sun Calcium Enno Seihou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing calcium salts of acrylic or methacrylic acid.

Specifically, the present invention involves reacting acrylic acid or methacrylic acid with a calcium compound to form a calcium salt of acrylic acid or methacrylate, thereby producing a powdery solid with high purity and substantially no water content. The present invention relates to a method for producing a calcium salt of acrylic acid or methacrylate.

Acrylic acid or methacrylic acid [hereinafter referred to as (meth)acrylic acid.

The calcium salt of ] is a compound useful as a crosslinking agent,
For example, it is used as a soil conditioner, a cement quick-setting agent, a modifier for synthetic resins, a co-vulcanizing agent for rubber, etc.

Among these various uses, calcium (meth)acrylate salt, which is used as an additive to synthetic resins and rubber, is particularly required in the form of a water-free, highly pure powder.

However, according to the findings of the present inventors, these calcium (meth)acrylate salts have a large binding force with water;
It has two molecules of water of crystallization, and it is very difficult to remove water from the salt, and it is difficult to suppress the polymerization reaction and remove water in the drying process to produce a high-yield, high-purity powdery solid product. It is a compound.

Conventionally, the method for producing calcium acrylic acid salt was
A method described in the specification of Publication No. 9-19148 is known, in which acrylic acid and a calcium compound are reacted in the presence of water, but the reaction is carried out in a state substantially close to a solid phase. Discloses a method for producing calcium acrylate salt.

However, when the present inventor investigated this method, it was found that when a powdered calcium compound is reacted with an aqueous acrylic acid solution as a spray additive, a reaction occurs between the solid and the droplets, which equalizes the temperature and the reaction. It is extremely difficult to maintain the purity of the product, causing local heat generation and the previously reacted parts forming lumps, resulting in poor reproducibility and poor product purity when manufactured using industrial-scale equipment. It cannot be said that this method is suitable for industrial use.

Conversely, in the method of sequentially dropping calcium compounds into acrylic acid, solid calcium acrylate precipitates as the reaction progresses, and in the latter stages of the reaction, a reaction occurs between the solids, resulting in a slow reaction. This results in non-uniformity and only a product with low purity can be obtained.

Therefore, in this case, the reaction cannot be completed unless a considerable amount of water is present in the acrylic acid.

In other words, in this method, water must be added to maintain the reaction system in a stirrable paste state, and this water can cause various problems in the subsequent drying process (polymer generation, residual moisture), etc. It has some disadvantages.

The present inventors tried various methods for producing a highly pure powdery solid containing substantially no water of calcium (meth)acrylate salt, and found that calcium (meth)acrylate salt was spray-dried at high temperature. Polymerization generates heat and ignites, and when concentrated and crystallized from an aqueous solution, it tends to adhere to the inner wall of the container.
and discovered that it easily causes polymerization (meta)
It was discovered that neither the spray drying method nor the concentration crystallization method from an aqueous solution of calcium acrylic acid salt could be adopted, and as a result, it was extremely difficult to remove water from the reaction product and dry it. There was found.

When (meth)acrylic acid and a calcium compound are reacted, 1 to 2 moles of water are always produced as a by-product per mole of the calcium salt.

Furthermore, the (meth)acrylic acid and calcium compound used as raw materials may also contain a small amount of water.

Therefore, it is essential to remove such water from the reactant.

The present inventors investigated various methods for removing existing water by reacting in a solvent that is azeotropic with water and performing azeotropic dehydration. The reaction was carried out in a solvent that has the property of being azeotropic with water, and the water content was maintained at a temperature of 40°C so that the calcium (meth)acrylate collected in the reaction system did not coagulate and precipitate. It was found that the desired high purity powdery solid could be obtained by reaction and dehydration drying at a temperature of 100°C to 100°C, leading to the completion of the present invention.

Thus, the present invention provides a highly industrially advantageous method for producing calcium (meth)acrylic acid salt powder that overcomes the drawbacks of conventional methods and is extremely easy to operate and control, with high yield, A method for producing highly pure, substantially anhydrous (meth)acrylic acid calcium salt powder is provided.

That is, in the present invention, when producing a calcium salt of acrylic acid or methacrylic acid by reacting acrylic acid or methacrylic acid with a calcium oxide, hydroxide, carbonate, bicarbonate, or a mixture thereof, mutually insoluble with water as a solvent in the substantial absence of water;
It is characterized by using a hydrocarbon compound capable of forming an azeotrope with water, carrying out a reaction within a temperature range of 40 to 100°C, removing water produced together with a solvent azeotropically, and further drying. The present invention provides a method for producing highly purified calcium acrylate or calcium methacrylate.

Similar to the method of the present invention, a method of azeotropic dehydration using an organic solvent is described in JP-A-47-11365.

However, this method relates to a method for producing an alkali metal salt of (meth)acrylic acid in the step of synthesizing glycidyl ester, and as is clear from the specification, potassium and sodium salts of (meth)acrylic acid are The reaction and physical properties are fundamentally different from calcium salts, and the reaction conditions are also essentially different.

That is, in the case of an alkali metal salt, the presence of water in the reaction system is an essential condition, but in the case of the calcium (meth)acrylate of the present invention, the reaction proceeds even in the absence of water. Moreover, it is preferable that substantially no water be present.

Further, in the method disclosed in the above-mentioned publication, dehydration is performed by azeotropic distillation of the solvent and water, but dehydration is not sufficient with this operation alone, and a solid desiccant must be used.

In the method of the present invention, there is no need to further use a desiccant after azeotropic dehydration, and it is sufficient to simply carry out the drying treatment.

These differences in composition between potassium and sodium salts and calcium salts are thought to be due to their reactivity, differences in binding strength with water, etc. It is clear that even with reaction dehydration in the presence of water, it is difficult to obtain highly pure, substantially water-free products.

The solvent used in the present invention is a hydrocarbon compound that is azeotropic with water and is not mutually soluble with water when cold, and has a boiling point of 50 to 160°C, preferably 80 to
Organic compounds within the range of 140°C are preferred, and specific examples include benzene, toluene, xylenes, cyclohexane, methylcyclohexane, n-hebutane, and n-hexane.

The (meth)acrylic acid used in the present invention is ordinary glacial (meth)acrylic acid that is not diluted with water, but it may contain some amount of water.

Furthermore, the presence of polymerization inhibitors such as hydroquinone and hydroquinone monomethyl ether contained in (meth)acrylic acid does not cause any problem.

Further, as the raw material calcium compound, a normal powdery solid is used.

If it is in powder form, it is convenient to charge it into the reactor, and it is also easily stirred and dispersed in the solvent.
The reaction with acrylic acid can be made uniform.

Although it is preferable that the raw material calcium compound does not contain water, there is no problem even if it contains some amount of water.

However, it is of course necessary that the water contained in the raw material calcium compound and (meth)acrylic acid be within a range that does not cause coagulation and precipitation of calcium (meth)acrylate produced when the water contained in the raw material calcium compound and (meth)acrylic acid are combined with the reaction product water.

If the raw material contains a lot of water, increase the amount of solvent used.

Calcium compounds used include calcium oxide, calcium hydroxide, calcium carbonate and calcium bicarbonate.

The reason why the water present in the reaction system has a great effect on the quality of the produced calcium (meth)acrylate salt in the present invention is considered to be as follows.

First, 1 to 2 mol of reaction water is generated per 1 mol of calcium (meth)acrylate by the reaction.

Most of the produced water and the water coming from the raw materials are bound to the crystals as calcium (meth)acrylate crystal water, but the rest is attached to the crystals as free water.

At this time, the more free water there is, the more crystals are liquefied and become a solution that surrounds the surface of the crystal, making it impossible for the hydrocarbons in the solvent to wet the surface of the crystal, resulting in agglomeration of the crystals and forming large clumps. It will precipitate.

These precipitated crystals tend to adhere strongly to the inner walls of the reactor, such as the heating surface, and during the reaction and dehydration and drying processes, some of these adhering crystals turn into polymers, causing quality deterioration or large Since it becomes lumpy, it becomes difficult to remove water in the dehydration and drying process.

In view of these facts, the most preferred embodiment of the present invention is
It is preferable to use substantially anhydrous raw material (meth)acrylic acid and calcium compound for the reaction.

Next, specific embodiments of the present invention will be described.

A sufficiently stirrable reactor is filled with a solvent, the calcium compound powder is stirred and dispersed, and then (meth)acrylic acid is added dropwise for reaction.

Alternatively, (meth)acrylic acid is mixed in advance in the above solvent, and the calcium compound powder is added and reacted with stirring.

The ratio of calcium compound and (meth)acrylic acid is (
It is preferable to use meth)acrylic acid in an amount of salt forming equivalent to about 10% excess relative to the calcium compound.

There is no limit to the amount of solvent used as long as it is at least the amount that can azeotropically remove the water present in the reaction system (total amount of reaction water and water coming from the raw material (meth)acrylic acid and calcium compound), but usually ( The amount may be about 5 to 15 moles per mole of meth)acrylic acid.

Within this range, the raw material calcium compound can be uniformly dispersed in the reaction system, heat can be conveniently removed without locally reacting with (meth)acrylic acid, and the (meth)acrylic acid Improves the dispersion of acid calcium salts,
Wrapping up of unreacted raw material calcium compounds also does not occur.

The reaction temperature is preferably 40 to 100°C.

This temperature is regulated by a cooler or power heater provided in the reactor.

If the reaction temperature is below 40°C, the reaction rate will be slow and it will take too much time, and if it is carried out at above 100°C, polymerization reaction will easily occur and the purity of the product will decrease.

Water present in the reaction system is removed by azeotropic distillation with the solvent, which may be carried out during the reaction or after completion of the reaction.

When performing azeotropic distillation during the reaction, it is better to separate the distilled solvent into two layers from water and then return it to the reaction system.

Otherwise, the amount of solvent in the reaction system will decrease, resulting in poor dispersion of the raw material calcium compound and calcium (meth)acrylic acid salt, which is disadvantageous.

At this time, since unreacted (meth)acrylic acid is present in the reaction system, a separation column is required to prevent (meth)acrylic acid from distilling off during azeotropic distillation.

After reaction azeotropic dehydration, the solvent is mechanically separated using a p-filter, centrifuge, etc., and the resulting calcium salt of (meth)acrylate is dried to remove the solvent at a temperature of 40 to 100°C to produce a product. I can do it.

In the case of azeotropic dehydration after the completion of the reaction, the reaction solution is transferred to a secondary oven, blender, etc. equipped with a stirrer with scraping blades, and heated at a temperature of 40 to 100°C and a pressure of 5 to 500 mmHg.
Dry under reduced pressure.

In this case, a mechanical separator and a separation column for separating the solvent and calcium (meth)acrylic acid salt are not necessary, and this is a more preferred embodiment of the present invention.

If the dehydration and drying temperature is below 40°C, the water of crystallization contained in calcium (meth)acrylate cannot be sufficiently removed, and the polymer will be included in the powder that is considered to be over 100°C. .

Example 1 Calcium hydroxide 95P (1.28 mol) was added to toluene 5
Suspend in 50CC and add 189P acrylic acid while stirring.
(2.63 mol) was added dropwise over 20 minutes.

The reaction temperature was maintained at 50°C and the mixture was stirred for 2 hours after the dropwise addition to complete the reaction.

Then, the obtained slurry was supplied to Niichigu and heated at 60℃.
When subjected to azeotropic distillation, dehydration, and drying treatment at 160 mmHg for 2 hours, powdered calcium acrylate 2331 having a moisture content of 1.9% by weight and a purity of 97.5% by weight was obtained.

No product adhesion to the kneader was observed at all.

Example 2 189 g of acrylic acid was dissolved in toluene iooocc, and 95 g of calcium hydroxide was mixed and reacted with the solution while stirring the solution while raising the temperature to 60°C.

The addition took place over a period of 20 minutes and was then incubated at 60°C for 2 hours.
A time reaction was performed.

The obtained slurry was supplied to a 21-gu tank and heated at 60°C for 16 minutes.
After azeotropic dehydration and drying treatment at 0 mmHg for 2 hours, powdered calcium acrylate 232r with a water content of 1.2% by weight and a purity of 96.5% by weight was obtained.

Comparative Example 1 Acrylic acid 189ti? was dissolved in toluene 'tooocc' and the temperature was raised to 50'C.

Then lime milk 20 containing 951 as calcium hydroxide
0? was added for 15 minutes at a temperature of 50° C. with stirring, and then the reaction was carried out for 2 hours.

The obtained slurry was supplied to a kneader and heated at 60°C and 160°C.
Although the drying treatment was carried out using hot Hg for 5 hours, a large amount of calcium acrylate adhered to the wall surface of the secondary drum during the operation, and some polymerization was also observed.

The quality of the obtained calcium acrylate was 75% by weight of water, 4.6% by weight of polymer, and 871% by weight of purity.

Comparative Example 2 Calcium hydroxide 50S' was added over 10 minutes to 125 g of 80% acrylic acid with sufficient stirring.

The reactor was water-cooled to maintain the temperature at 60°C. As the addition progressed, the viscosity of the reaction slurry increased, and by the end of the addition it had become cake-like.

This was further reacted at 60° C. for 1 hour and then cooled to room temperature, forming a solid lump that could not be easily crushed.

In addition, in a separate experiment, when the material was heated without being cooled to room temperature, the crystals adhered firmly to the vessel wall.

As a result of drying the obtained product at 60°C for 6 hours, the moisture content was 6
．． 137 g of calcium acrylate mixture with a purity of 88.2% and a purity of 88.2% were obtained.

Example 3 3.33 kg of calcium hydroxide was suspended in 187 1-toluene, 6.81 kg of acrylic acid was dissolved in 30 minutes with stirring, and the suspension was reacted at 50° C. for 3 hours.

The obtained slurry was heated to 60°C using a ribbon blender.1.
At 50 mmHg, azeotropy and dehydration of the solvent and the produced water are carried out, and as the amount of solvent distilled begins to decrease, the pressure is gradually reduced to 50 mmHg.
Drying was carried out for 5 hours while lowering the temperature to 0 mmHg, yielding 8.19 ky of calcium acrylate powder with a moisture content of 1.8% and a purity of 98%.

There was no product adhesion to the blender walls or blades.

Example 4 37 g of calcium hydroxide was suspended in 300 CC of benzene, 72 g of acrylic acid was added dropwise over 10 minutes at 60° C. with stirring, and the reaction was completed by stirring at 60° C. for 2.5 hours.

The resulting slurry was then dried in a kneader at 50°C and 170°Hg for 3 hours, resulting in a moisture content of 2.3% and a purity of 97.
5% calcium acrylate powder90. I got an IP.

Example 5 37 g of calcium hydroxide was suspended in 30 Qcc of toluene, 90 g of methacrylic acid was added dropwise at 85° C. over 20 minutes with stirring, and the reaction was completed by stirring at 85° C. for 3.5 hours.

The obtained slurry was dried in the same manner as in Example 1, and the moisture content was reduced to 1.
Powdered calcium methacrylate 102i with a purity of 96.2% was obtained.

Claims (1)

[Claims] 1. When producing a calcium salt of acrylic acid or methacrylic acid by reacting acrylic acid or methacrylic acid with a calcium oxide, hydroxide, carbonate, bicarbonate, or a mixture thereof, substantially no water is added. Using a hydrocarbon compound that is mutually insoluble with water and capable of forming an azeotrope with water in the absence of water as a solvent, at a temperature of 40 to io
1. A method for producing a calcium salt of acrylic acid or methacrylic acid, which comprises carrying out a reaction within a temperature range of 0.degree. C., azeotropically removing water produced together with a solvent, and drying.