JPS6218542B2 - - Google Patents

Description

[Detailed description of the invention] The present invention is based on the general formula CH ₂ =CR ₁ -COOCH ₂ CH ₂ NR ₂ R ₃ ...(1) (R ₁ is -H or -CH ₃ , R ₂ , R ₃ are -CH ₃ or −C ₂ H ₅ ) is reacted with a halogenated hydrocarbon in an aqueous solution to form the general formula [CH ₂ = CR ₁ −COOCH ₂ CH ₂ NR ₂ R ₃ R ₄ 〕 ⁺ × ⁻
…(2) (R ₁ , R ² , R ₃ are the same as before, R ₄ is -CH ₃ or -C ₂ H ₅ , X is Cl or Br) 82～93
% by weight of an aqueous solution or an aqueous slurry (hereinafter referred to as aqueous slurry).

Polymers represented by the general formula (2) or copolymers containing a predominant monomer represented by the general formula (2) are recognized to be excellent as cationic flocculants, and are used in industrial wastewater and domestic wastewater. It is widely used as a clarifying agent for organic sludge and as a dewatering aid for organic sludge. It is also used as a papermaking aid and a fiber treatment agent.

Conventionally, various methods for producing this polymer have been reported, such as a method of polymerizing in an aqueous solution with a water content of 40% by weight or more, drying, and then pulverization, a method of precipitation polymerization or suspension polymerization in an organic solvent, A method has been proposed in which the organic solvent is removed, dried, and then pulverized. However, these methods require drying equipment to remove a large amount of water, and use organic solvents that need to be careful of ignition and explosion, so they are not necessarily advantageous from an industrial perspective. do not have.

In contrast, the present applicant polymerized the monomer represented by general formula (2) by adding 7 to 18% by weight of water,
proposed a method to obtain bulk polymers (Japanese Patent Application Laid-Open No. 1983-1999)
No. 133388, hereinafter this technology is referred to as ultra-high concentration polymerization technology).

If polymerization is carried out according to this method, a polymer that is easily pulverized as it is can be obtained, so a drying step is not necessary, and an organic solvent is also not necessary.

By the way, in order to obtain a monomer aqueous slurry containing 82% by weight or more of the unsaturated quaternary ammonium salt represented by the general formula (2), the tertiary amine represented by the general formula (1) is usually halogenated in an organic solvent. react with hydrocarbons,
The quaternized product is precipitated as crystals, separated, and then adjusted to the desired concentration, or the general formula (1)
The tertiary amine represented by is quaternized in an aqueous solution at a concentration of 80% by weight or less, and a crystalline quaternized product prepared in advance in the resulting quaternary salt aqueous solution, for example, obtained by the method described above. Methods such as adjusting the concentration by adding However, for example 4
In order to increase the concentration of 1 kg of an 80% by weight aqueous solution of a grade salt into a 90% by weight aqueous slurry, another 1 kg of crystals must be used, which has the disadvantage of requiring a large amount of crystals.

On the other hand, since crystal production requires organic solvents such as acetonitrile and dimethylformamide, it is a matter of course that organic solvent removal equipment and recovery equipment are required on an industrial scale. Furthermore, these organic solvents are undesirable from an industrial perspective since they pose a risk of ignition and explosion, which increases the burden on disaster prevention equipment.

Various methods for quaternizing tertiary amines in aqueous solutions have been reported (for example,
(No. 101914, No. 52-31017) Stabilization methods have also been studied and effective polymerization inhibitors have been discovered (Japanese Patent Application Laid-open No. 52-36620).

However, the concentration of the quaternary salt represented by general formula (2) obtained by quaternization in an aqueous solution is 80% by weight.
If this is used directly, the advantages of the ultra-high concentration polymerization cannot be fully obtained.

The reason why quaternary salts cannot be obtained at ultra-high concentrations is that the normal reaction temperature for quaternization reactions is 30 to 40℃.
This is because the concentration of the quaternary salt exceeds the saturated solubility and crystals precipitate, causing problems such as scaling on the surface from which reaction heat is removed, making cooling impossible.

In the case of laboratory-scale reactions, if the stirring intensity and temperature of the cooling surface are carefully controlled, crystals may not precipitate even at a concentration of 87%, but this is because the supersaturated concentration of the quaternary salt is large. However, it is difficult to maintain a stable reaction state on an industrial scale.

Under these circumstances, a method for quaternizing an aqueous solution containing the monomer of general formula (1) at a concentration of 80% by weight or more has also been specifically proposed. (Unexamined Japanese Patent Publication No. 52-31017)
However, the content is that when the quaternary salt exceeds the saturation amount and precipitates, water is added to dissolve the crystals, and the ultra-high concentration of quaternary salt as in the present invention is An aqueous slurry cannot be obtained.

The present invention provides a method for quaternizing an ultra-high concentration tertiary amine represented by the general formula (1) in the state of an aqueous solution to obtain an aqueous slurry of a quaternary salt without problems such as scaling onto a cooling surface. It is.

In order to terminate the quaternization reaction at an extremely high concentration as described above without precipitating crystals, the reaction may be carried out at a temperature above which crystals do not form. In this case, the reaction may be carried out at a low temperature at the initial stage and the temperature of the reaction system may be gradually raised as the reaction progresses. In any case, the temperature at the end of the quaternization reaction is approximately 50 to 70℃.
becomes.

In the method described in JP-A-51-133388, which is an ultra-high concentration polymerization technique, the polymerization initiation temperature is about 10 to about 30°C. Therefore, it is necessary to cool the aqueous solution of the quaternary salt monomer represented by the general formula (2) obtained from the general formula (1). By this operation, crystals are precipitated in the monomer aqueous solution.

If the size of the crystals precipitated in this way is large to some extent, when the monomer represented by general formula (2) is subjected to ultra-high concentration polymerization, the monomer will precipitate during the induction period of polymerization. In addition, if polymerization occurs while crystals are precipitated, the resulting bulk polymer may not be able to be pulverized as it is because the quaternary salt concentration is low in the upper layer without crystals.

The present inventors discovered that the high-temperature 4
When the aqueous salt solution was stirred and mixed with the cooled tertiary amine and left to stand, a 4-chloride solution containing extremely fine crystals was obtained.
It was discovered that the solubility of the tertiary amine in the lower layer and the solubility of water and quaternary salt in the upper layer is very low. This led to the present invention.

Normally, a large amount of equipment is required for cooling and crystallization, and it is often difficult to take measures against scaling, etc., but according to the present invention, there is no need for a special equipment for crystallization. A highly pure quaternary brine slurry is obtained.

The reason why fine crystals suitable for ultra-high concentration polymerization are obtained is thought to be that the high temperature quaternary salt aqueous solution is rapidly cooled.

The tertiary amine represented by the general formula (1) is freely soluble in water, but the quaternary salt represented by the general formula (2) derived from this tertiary amine is not freely soluble in water. do not have.

However, when a tertiary amine and a quaternary salt are mixed in an extremely small amount of water as intended by the present invention, this system becomes a tertiary amine containing almost no water or quaternary salt.
They discovered that the tertiary amine layer separates into an aqueous slurry layer of quaternary salt containing almost no tertiary amine, and also came up with the idea of using the tertiary amine, which is a reaction raw material, as a refrigerant for the quaternary salt aqueous solution. The present invention was formed by this.

A very small amount of tertiary amine is dissolved in the aqueous slurry of the quaternary salt obtained as described above, and this may be further quaternized using a halogenated hydrocarbon, but it is usually polymerized. Make a tertiary salt with an inorganic acid that is used to adjust the pH to about 3 to about 5, and use the formula (2)
Copolymerization occurs during the polymerization of the quaternary salt represented by, but since the amount thereof is very small, a polymer equivalent to a homopolymer can be obtained.

The molar ratio of halogenated hydrocarbon to tertiary amine during the quaternization reaction in the present invention is not particularly limited as long as it is around equimolar.

Further, it is not necessary to complete the quaternization reaction. The reason is that when the reaction solution is poured into a cooled tertiary amine and stirred, unreacted halogenated hydrocarbons are
This is because the unreacted tertiary amine is consumed in the grading process, and the unreacted tertiary amine is extracted into the tertiary amine layer, which is a refrigerant.

The quaternary salt aqueous solution and the third refrigerant after the quaternization reaction
The method of contacting the secondary amine may be such that the former is injected into the latter and stirred, or vice versa. Furthermore, another device may be provided to inject and mix both at the same time.
However, in order to obtain finer crystals, preferable results are often obtained by injecting the former into the latter or by simultaneous injection mixing using another device.

The present invention will be explained below with reference to Examples.

Example 1 Internal volume 1000ml with stirrer and gas blowing tube
A reactor was charged with 658 g of dimethylaminoethyl methacrylate (hereinafter referred to as DMAEMA), 130 g of water, and 2 g of monomethylhydroquinone, and then 211 g of methyl chloride (equivalent to DMAEMA) was blown into the reactor over a period of 4 hours while stirring.

The temperature of the reaction solution was initially adjusted externally to 35°C, and was increased as the reaction progressed to 60°C at the end of the reaction.

This reaction solution (1000g) was heated to -5℃.
When poured into 1000 g of DMAEMA and stirred strongly, the quaternary salt aqueous solution was rapidly cooled to 30°C and fine crystals precipitated. When stirring was continued gently for about 10 minutes, the mixture was separated into an upper layer mainly composed of DMAEMA and a lower layer mainly composed of quaternary salt and water, so stirring was stopped and the mixture was allowed to stand still, and the composition of both layers was analyzed.

The water content in the upper layer was about 0.9% by weight, and the quaternary salt was about 0.4% by weight. After removing quaternary salt crystals by centrifugal sedimentation, the lower layer was analyzed and found to contain approximately 2% by weight of DMAEMA and approximately 20% by weight of water.

Of course, this upper layer of DMAEMA can be used for the next reaction.

Example 2 500 g of a quaternary salt aqueous solution at 60°C obtained by the reaction in the same manner as in Example 1 was poured into 1000 g of dimethylaminoethyl methacrylate at 12°C and stirred vigorously. The quaternary salt aqueous solution was rapidly cooled. Fine crystals precipitated.

Thereafter, two layers were separated by the same operation as in Example 1,
Analysis of the composition of each layer revealed that the water content in dimethylamino methacrylate (upper layer) was approximately 0.9% by weight.
The quaternary salt was about 0.4% by weight, the dimethylaminoethyl methacrylate in the quaternary salt aqueous solution was about 2% by weight, and the water was about 20% by weight.

Comparative example: The same raw materials were charged into the same reactor as in Example 1,
The same methyl chloride was blown into the solution to cause a reaction. The reactor was insulated and the reaction temperature was controlled at 35°C through a cooling coil inside. The reaction, in which the temperature of the water passed through the cooling tube was controlled at 10°C, initially proceeded in the same manner as in the example, but the reaction rate was approximately 90°C.
%, quaternary salt crystals adhere firmly to the surface of the cooling coil, and the reaction temperature becomes uncontrollable.
Since the temperature started to rise, the blowing of methyl chloride was stopped and the reaction was stopped.

Claims (1)

[Claims] 1 General formula CH ₂ = CR ₁ −COOCH ₂ CH ₂ NR ₂ R ₃
...(1) (R ₁ is -H or -CH ₃ , R ₂ , R ₃ are -CH ₃ or -C ₂ H ₅ ) and a halogenated hydrocarbon. The reaction results in the general formula [CH ₂ = CR ₁ −COOCH ₂ CH ₂ NR ₂ R ₃ R ₄ ] ⁺ × ⁻
...(2) (R ₁ , R ₂ , R ₃ are the same as before, R ₄ is -CH ₃ or -C ₂ H ₅ , X is Cl or Br) 82～93
To obtain an aqueous solution (or aqueous slurry) containing % by weight, the solution after the reaction and the tertiary amine at a temperature below the temperature of the solution after the reaction are mixed and phase separated to obtain an aqueous solution (or aqueous slurry) of the quaternary salt. A method for producing an unsaturated quaternary ammonium salt, the method comprising: obtaining an unsaturated quaternary ammonium salt;