JP2001131228A - Method for production of polyvinyl imidazoline - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrial production method whereby polyvinylimidazoline which is not colored brown and does not emit a bad odor is produced without the necessity for the step of pulverizing polyvinylimidazoline. SOLUTION: A solid is separated out while a reaction liquid prepared by reacting a nitrile-group-containing polymer with a polyamine is added to tetrahydrofuran.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing polyvinylimidazoline. Polyvinylimidazoline is a compound useful as, for example, a polymer flocculant.

[0002]

2. Description of the Related Art As a method for reacting a polymer of acrylonitrile or methacrylonitrile with a polyamine to recover polyvinyl imidazoline or a salt thereof, a freeze-drying method or a precipitation from a solution, for example, a precipitation from an aqueous solution of a polymer is used. Is known by the method of recovery by
2-6271).

[0003] The method of recovering a solid polymer by freeze-drying requires not only a long time but also a pulverization of the obtained polyvinyl imidazoline or a salt thereof for commercialization.

There is also disclosed a method in which a reaction solution is poured into a large excess of acetone to cause precipitation and separation and drying. However, according to this method, unreacted polyamine such as ethylenediamine reacts with acetone to generate a Schiff base, which is taken into polyvinylimidazoline, and is colored brown to cause offensive odor.

[0005]

As described above, the conventional method for crystallizing polyvinyl imidazoline requires a pulverizing step, or even if the pulverizing step can be omitted by crystallization with acetone, the polyvinyl imidazoline turns brown. Problems such as coloring and offensive odor occurred, and were not industrially satisfactory.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a polyvinyl imidazoline which does not require a pulverizing step of polyvinyl imidazoline and which does not cause brown coloring or offensive odor. It is to provide a method that can be manufactured in a reliable manner.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies on the crystallization method of polyvinylimidazoline in order to solve the above problems, and as a result, using tetrahydrofuran as a solvent during crystallization, By dropping, the crystals were not solidified during the crystallization, the obtained polyvinylimidazoline was not colored brown, and it was found that an almost odorless solid was obtained, and the present invention was completed. .

That is, the present invention provides a reaction solution obtained by reacting a polymer having a nitrile group with a polyamine,
Precipitate a solid while adding to tetrahydrofuran, or
Alternatively, there is provided a method for producing polyvinyl imidazoline, which comprises depositing polyvinyl imidazoline or a salt thereof as a solid while adding tetrahydrofuran to a reaction solution obtained by reacting a polymer containing a nitrile group with a polyamine.

Hereinafter, the present invention will be described in more detail.

The polyvinyl imidazoline reaction solution is produced by a known method from a polymer containing a nitrile group such as an acrylonitrile or methacrylonitrile polymer and a polyamine. As long as the polymer containing a nitrile group is dispersed, the reaction may be carried out using a polyamine bulk without using a solvent during the reaction, or a solvent may be used. When a solvent is used, it is not preferable to use a substance that decomposes imidazoline, such as water, but any solvent can be used without particular limitation as long as it is inert to the reaction conditions.

In the method of the present invention, a large amount of polyamine remains in the case of polyamine bulk reaction, and unreacted polyamine remains even in the reaction using a solvent. Therefore, it is preferable to remove unreacted polyamine from the reaction solution after the reaction.

In the method of the present invention, the polyamine can be removed by depositing polyvinylimidazoline from the reaction solution. As the method, 1) a method in which a reaction solution obtained by reacting a polymer containing a nitrile group with a polyamine is precipitated as a powder while adding it to tetrahydrofuran, 2) a reaction between the polymer containing a nitrile group and a polyamine The reaction can be carried out by any of the methods of depositing a powder while adding tetrahydrofuran to the reaction solution obtained. Even if acetone is used as a crystallization solvent at this time, polyvinyl imidazoline can be precipitated in powder form, but on the other hand, the remaining polyamine and acetone react to generate a Schiff base, and the precipitated polyvinyl imidazoline is formed. It is taken in. This Schiff base causes the polyvinyl imidazoline to be colored brown or cause an irritating odor. However, tetrahydrofuran as a crystallization solvent in the present invention can avoid such a reaction, and can recover polyvinyl imidazoline without generating a Schiff base.

In the method of the present invention, the amount of tetrahydrofuran relative to the reaction solution depends on the amount of unreacted polyamine and, when a solvent for dissolving polyvinylimidazoline is used, depends on the amount of tetrahydrofuran. It is difficult to determine the quantity. However, if the amount of tetrahydrofuran is too small, the polyvinyl imidazoline does not precipitate, or is redissolved even after the precipitation, and the resulting polyvinyl imidazoline becomes tacky.
The larger the amount of the unreacted polyamine and the amount of the solvent in which the polyvinyl imidazoline is dissolved, the easier the crystallization.

The polyvinylimidazoline slurry solution obtained is separated from the solvent by filtration or centrifugation and dried to obtain polyvinylimidazoline powder as a product.

The reaction solution used in the method of the present invention can be obtained by a known method.
For example, as the catalyst, conventionally known catalysts such as ammonium chloride, amine hydrochloride, and sulfur can be used.

As a polymer containing a nitrile group, an acrylonitrile or methacrylonitrile polymer may be a uniform polymer or a copolymer. Acrylonitrile, monomers that can be copolymerized with methacrylonitrile include vinyl chloride, vinyl bromide, vinyl halides such as vinyl fluoride, vinylidene halides such as vinylidene chloride, acrylic acid, methacrylic acid, itaconic acid,
Unsaturated carboxylic acids such as maleic anhydride and salts thereof, (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate, and unsaturated ketones such as methyl vinyl ketone and methyl isopropenyl ketone , Vinyl esters such as vinyl acetate and vinyl benzoate, vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, (meth) acrylamide and its alkyl-substituted products, vinyl sulfonic acid, (meth) allyl sulfonic acid, and p-styrene sulfonic acid Sulfonic acids such as acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, (meth) acryloyloxyethylsulfonic acid and salts thereof, styrenes such as styrene, α-methylstyrene, chlorostyrene and alkyl- or halogen-substituted products thereof , Allyl alcohol Bisono esters or ethers, vinyl pyridine, vinyl pyrimidine, vinyl pyrrolidone, vinyl imidazole, dimethyl aminoethyl methacrylate, vinyl benzyl dimethylamine question basic vinyl compounds and the like.

The polyamine to be reacted with the nitrile group-containing polymer is 1,2-diamine. 1,2-Diamine is represented by the following formula (1).

H ₂ NCHR ¹ CHR ² NHR ³ (1) (wherein R ¹ , R ² and R ³ are each independently hydrogen, aliphatic,
Means one or more selected from the group consisting of araliphatic and aromatic groups) Examples of 1,2-diamine include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and aminoethylenepiperazine. Ethyleneamine, diaminopropane, diaminobutane, diaminopentane, diaminohexane, diaminoheptane, diaminooctane, diaminononane, diaminodecane, cyclohexylethylenediamine, benzylethylenediamine, phenylethylenediamine, methoxyphenylethylenediamine, dimethylphenylethylenediamine, tolylethylenediamine,
N-cyclohexylethylenediamine, N-benzylethylenediamine, N-phenylethylenediamine, N-
Methoxyphenylethylenediamine, N-dimethylphenylethylenediamine, N-tolylethylenediamine,
Examples include N-methylethylenediamine, N-ethylethylenediamine, N-isobutylethylenediamine, N-phenylethylenediamine, N- (2-aminoethyl) ethylenediamine, and the like.

In the method of the present invention, the reaction temperature for obtaining a reaction solution is usually in the range of 60 to 200 ° C., but is more preferably 70 to 180 ° C. 200
The reaction can be carried out even at a temperature higher than ℃, but the molecular chain of the acrylonitrile or methacrylonitrile polymer as a raw material is cut off, resulting in a low molecular weight. If the reaction temperature is lower than 60 ° C., the reaction rate becomes extremely slow, and the amount of the catalyst must be increased, which is not economical.

The production of the reaction solution is usually carried out in a liquid phase. The reaction may be carried out under normal pressure or under pressure, as long as the raw materials can be kept in a liquid, solution or suspension state. In this reaction, ammonia is generated during the reaction.
Although the pressure increases, this ammonia can be removed during the reaction or after the reaction is completed. When the reaction temperature exceeds the boiling point of the raw materials, a method of performing the reaction under pressure, providing a condenser, or supplying the raw materials little by little can be employed.

The polyvinylimidazoline in the present invention includes itself and a salt thereof. In the case of a polyvinyl imidazoline salt, it can be easily converted to a salt, for example, by contact with an acid. Specifically, by adding an equivalent amount of hydrogen chloride to polyvinylimidazoline, it can be converted to polyvinylimidazoline chloride. If the catalyst used is, for example, an ammonium salt, the hydrochloride of polyvinylimidazoline can be produced by the generated hydrogen chloride.

[0022]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 Polyacrylonitrile (weight average molecular weight 86,000) 5
g and 40 g of 1-propanol were placed in a flask, and the flask was purged with nitrogen and stirred. Then, 13.4 g of ethylenediamine and 5 g of ammonium chloride were added to start heating. After heating at 95 ° C. for 7 hours, the mixture was cooled, a viscous yellow solution was taken out, and added dropwise to 280 g of tetrahydrofuran.
It became a white powder. When this was dried, 11.5 g of a white polyvinyl imidazoline powder was obtained. This powder was odorless.

Example 2 A reaction was carried out in exactly the same manner as in Example 1, and 280 g of tetrahydrofuran was added dropwise to the resulting reaction solution, whereby a white powder was obtained. When this was dried, 12.7 g of a white polyvinylimidazoline powder was obtained. This powder was odorless.

Example 3 Polyacrylonitrile (weight average molecular weight 86,000) 5
g was placed in a flask, and after purging with nitrogen, 30 g of ethylenediamine and 0.05 g of ammonium chloride were added to start heating. After heating at 95 ° C. for 27 hours, the mixture was cooled and a viscous yellow solution was taken out.
Dropping into 80 g resulted in a granular solid. When this was dried, 8.5 g of granular polyvinyl imidazoline was obtained. This granular polyvinyl imidazoline was pale yellow and odorless.

Comparative Example 1 A reaction was carried out in exactly the same manner as in Example 1, and 280 g of acetone was added dropwise to the resulting reaction solution to give a yellow powder. When this was dried, 11.5 g of a brownish polyvinyl imidazoline powder was obtained. This powder had a pungent odor.

Comparative Example 2 A reaction was carried out in exactly the same manner as in Example 3, and 280 g of acetone was added dropwise to the resulting reaction solution, whereby a yellow granular solid was obtained. When this was dried, 12.7 g of brownish polyvinyl imidazoline was obtained. This polyvinyl imidazoline had a pungent odor.

Comparative Example 3 A reaction was carried out in exactly the same manner as in Example 3, and n was added to the obtained reaction solution.
When 280 g of -hexane was added dropwise, solid crystals did not completely precipitate, but remained viscous and became a lump. As a result, unreacted ethylenediamine could not be completely removed, and the surface of the lump remained sticky.

[0029]

According to the method of the present invention, there is provided a method capable of industrially producing polyvinyl imidazoline which does not require a pulverizing step of polyvinyl imidazoline and which does not cause brown coloring or offensive odor. Which is extremely significant.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J100 AB02Q AB03Q AB07Q AB08Q AC03Q AC04Q AC11Q AC23Q AD03Q AE03Q AE04Q AF10Q AG04Q AJ02Q AJ08Q AK32Q AL03Q AL08Q AM02P AM15Q AM21Q AP01Q AQ08Q AQ12Q AGC12QAQ19 HC43 JA18

Claims (3)

[Claims] 1. A method for reacting a polymer containing a nitrile group with a polyamine, wherein the reaction mixture is added to tetrahydrofuran, and polyvinylimidazoline or a salt thereof is precipitated as a solid. Production method. 2. A method of reacting a polymer containing a nitrile group and a polyamine, wherein polyvinylimidazoline or a salt thereof is precipitated as a solid while adding tetrahydrofuran to a reaction solution obtained by reacting the polymer with a polyamine. Production method. 3. The polymer according to claim 1, wherein the polymer containing a nitrile group is a homopolymer or a copolymer of acrylonitrile or methacrylonitrile.
The production method described in 1.