KR101824325B1 - Preparation method of polyvinylamine - Google Patents

Abstract

Disclosed is a method for preparing polyvinylamine through a process of improving a conversion ratio of vinylamine by directly modifying acrylamide monomers. The method for preparing polyvinylamine comprises performing Hofmann rearrangement by reacting acrylamide monomers with an alkali catalyst and water, synthesizing vinylamine monomers, polymerizing the vinylamine monomers and preparing polyvinylamine.

Description

PREPARATION METHOD OF POLYVINYLAMINE [0002]

More particularly, the present invention relates to a water-soluble surface modifier such as paper, fiber and film, and a process for producing polyvinylamine for use as a filler.

Polyvinylamine is a water-soluble polymer with high density and strong cationic property, which greatly improves the tensile strength and tear strength of paper when mixed with paper. When polyvinylamine is added at equivalent mechanical strength, Reduce opacity, improve dimensional stability, and change the physical properties of the surface to be used in the film to non-hydrophobic to improve the application of the aqueous coating. It has also been used as a surface modifier for dye settlement prior to fiber dyeing.

Polyvinylamines have traditionally been synthesized in polyvinylformamide. When polyvinylamine or vinylamine copolymer is synthesized by simply heating N-vinylformamide or a copolymer thereof to a temperature of 50 to 225 ° C. using a transition metal catalyst, the selectivity of the polyvinylamine is increased up to 63% in the palladium catalyst (U.S. Patent No. 5,491,199). However, the method using polyvinylformamide does not have residual acrylamide in the process of polyvinylamine synthesis, but the raw material cost is high and it is difficult to commercialize.

On the other hand, a process for converting polyacrylamide to polyvinylamine is disclosed. This process utilizes the Hoffmann rearrangement method and allows the use of relatively inexpensive raw materials, but there are many residual acrylamides in the synthesis process, thus bringing the salt content to about 30% of the total solids. Bromine gas and sodium hydroxide are used as catalysts. The lower the reaction temperature, the higher the selectivity of polyvinylamine. T.A. Stegall, MS Thesis, North Carolina State University, 2013.

Also, there is an example in which polyacrylamide is synthesized as polyvinylamine by reacting at -5 ° C using sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) as a catalyst (H. Tanaka, J. Polym. Chem. Ed., 17, 1239, 1979), a nonionic emulsion polyacrylamide polymer was prepared, powdered through drying, dissolved in an aqueous solution, and then modified with sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) To prepare polyvinylamine (Korean Patent Publication No. 10-1395270).

The method of synthesizing polyvinylamine from such polyacrylamide has been developed in order to solve the economical problem of product due to high raw material value when polyvinylformamide is used, and to synthesize polyacrylamide as a water-soluble polymer which is less expensive , There is a problem in that conversion rate is low when polyvinylamine is produced through rearrangement of Hoffmann in polyacrylamide having a polymer form.

Therefore, there is a need to develop a method for synthesizing polyvinylamine, which enables a more efficient selectivity by improving the conversion ratio using an inexpensive raw material as a starting material for polyvinylamine synthesis.

As described above, polyvinylformamide is produced by the condensation reaction of acetaldehyde and formaldehyde at a high price. However, since the manufacturer is limited to one foreign company and the raw material cost is high, when the product is used as a strength increasing agent, product economical efficiency is remarkably decreased due to high raw material value, A method of synthesizing polyacrylamide from polyacrylamide which is a more inexpensive water-soluble polymer has been developed. However, when polyvinylamine is prepared through rearrangement of Hoffmann in polymer-type polyacrylamide, a new synthetic method with lower selectivity is required.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above problems, and it is an object of the present invention to provide a process for producing polyvinylamine by directly modifying an acrylamide monomer to improve the conversion of vinylamine.

In order to solve the above problems, the present invention provides a method for producing a polyvinylamine, which comprises reacting an acrylamide monomer with an alkali catalyst and water to carry out Hoffman rearrangement to synthesize a vinylamine monomer and then polymerizing the vinylamine monomer, And a method for producing the same.

Further, the present invention provides a method characterized by using sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) as the alkali catalyst.

And sodium hydroxide (NaOH) is used in an amount of 10 to 50 molar ratio relative to the acrylamide monomer.

In addition, the sodium hypochlorite (NaOCl) is used in an amount of 0.3 to 1.5 molar ratio relative to the acrylamide monomer.

Further, the above-mentioned vinylamine monomers are synthesized by secondary reaction of sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) in a first reaction followed by rearrangement of Hoffmann and then sodium hypochlorite (NaOCl) to provide.

Also, the synthesis of the vinylamine monomer is carried out at a reaction temperature of -15 to 50 ° C.

The polymerization may also be carried out in the presence of a base such as 2,2-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis [2- Azobis [2- (2-imidazolin-2-yl) propane] dysulfate dihydrate and 2,2'-azobis [N- (2-carboxyl) 2- methylpropionamidine] Wherein at least one azo initiator selected from the group consisting of an azo initiator is used.

And the polymerization is carried out at a reaction temperature of 20 to 50 ° C.

According to the present invention, in the polyvinylamine production method, the acrylamide monomer is directly converted into vinylamine by using a specific catalyst system using an acrylamide monomer as a starting material to maximize the selectivity of vinylamine, thereby improving the cation density in the entire copolymer , And after the vinylamine synthesis, they are polymerized as it is without separate separation step, so that polyvinylamine which is a water-soluble, water-soluble polymer can be produced.

In addition, polyvinylamine, which is produced by polymerizing vinylamine monomer with high selectivity while using an inexpensive acrylamide monomer as a starting material for synthesis and polymerizing the synthesized vinylamine monomer, is a new water-soluble polymer and has a high charge density. It is expected that it will contribute to the demand for used paper, fiber, film and film.

1 is a view for explaining a continuous reaction process for producing polyvinylamine according to the present invention.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately The present invention should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention. Accordingly, it is to be understood that the constituent features of the embodiments described herein are merely the most preferred embodiments of the present invention, and are not intended to represent all of the inventive concepts of the present invention, so that various equivalents, And the like.

The present invention discloses a process for producing polyvinylamine by polymerizing vinylamine monomers after synthesis of vinylamine monomers by reacting acrylamide monomers with an alkali catalyst and water to perform Hoffmann rearrangement .

The polyvinylamine produced according to the present invention and the vinylamine monomer as the monomer are cationic polymers having a high charge density and are industrially water-soluble polymers having high potential for use in various applications. But it is difficult to mass-produce the polymer because it is necessary to use expensive raw materials for production as described above. That is, polyvinylamines having a strong amine group density are initially synthesized from poly (N-vinylformamide), poly (N-vinylacetamide) (DJ Dawson, RD Gless and RE Wingard, J. Am. Chem. Soc., 98 , 5996, 1976) and poly (N-vinyl tert-butyl carbamate) (R. Hart, Makromol.Chem., 32, 51, 1959), but in most cases the cost of raw materials is high It was not able to proceed with practical commercialization. Among them, poly (N-vinylformamide) was the most actively studied. Poly (N-vinylformamide) is a polymer of vinylformamide obtained by dehydration of acetaldehyde and formamide. This has been limited in its limited use due to the use of expensive raw materials, and actual manufacturing companies are only a few in the world. The degree of amination of polyvinylformamide to polyvinylamine conversion reaches nearly 99%. The synthesis of polyvinylamine via vinylformamide is shown in Scheme 1 below.

[Reaction Scheme 1]

The conversion reaction is carried out by radical polymerization of vinylformamide obtained by dehydration of acetaldehyde and formamide to produce polyvinylformamide and heating to 50 to 225 ° C in an aqueous solution using a catalyst composed of a transition metal (Group 8) To synthesize polyvinylamine. When polyvinylamines are prepared from polyvinylformamide, the reaction temperature is important next to the catalyst. The reaction temperature is suitably from 120 to 180 ° C. In this case, the degree of amination reaches 99%, but formic acid, a by-product, is generated. However, formic acid can easily be removed with water by distillation at about 105 ° C. (M. F. Ford, US Pat. No. 5,491,199, 1996).

Although the process for producing vinylamine through such vinylformamide is relatively easy and well known, there are disadvantages in that the manufacturer of vinylformamide is limited and the price is high. As described above, the polyacrylamide A method for producing polyvinylamine has been studied. In this method, a halogen compound is used as a catalyst in a strong base and Hoffmann rearrangement method is used. However, the production cost is low using an inexpensive raw material, but the salt compound has a high content of residual acrylamide of about 30% with respect to the total solid content.

Specifically, the Hoffmann rearrangement method can remove carbon dioxide from the polyacrylamide by an alkali halogen catalyst and arrange the amino group to a carbon atom. Examples of the alkali catalyst include sodium hydroxide (NaOH), sodium hypochlorite (NaOCl) and sodium hypobromite NaOBr) was used, and bromine (Br ₂ ) was used as a halogen compound. When an N-alkyl isocyanate is formed as an intermediate, it reacts with water again to produce carbon dioxide and vinylamine. When polyvinylamine is produced from polyacrylamide, the production cost is significantly lower than that of vinylformamide, but residual acrylamide is present and salt is generated during the synthesis reaction, resulting in about 30% of the total solid content, Thereby reducing the ion density.

On the other hand, partial amination reaction can form polyvinylamine, which is a reaction for forming polyvinylamine by causing aminization reaction with sodium hypobromite in polyacrylamide, and relatively stable polyvinylamine can be produced. However, Unreacted acrylamide may be present (see Scheme 2 below).

[Reaction Scheme 2]

In the present invention, when polyacrylamide is used as a starting material, an increase in the salt content due to residual acrylamide and a reduction in ion density due to this phenomenon can be prevented by using an acrylamide monomer with sodium hydroxide and sodium hypochlorite as catalysts, And solved by synthesizing monomers. Scheme 3 illustrates a process for synthesizing polyvinylamine according to the present invention.

[Reaction Scheme 3]

Acrylamide monomer as a starting material, sodium hydroxide and sodium hypochlorite are first added to cause Hoffman rearrangement, and then sodium hypochlorite is added secondly to increase the selectivity of vinylamine by 70% or more so that the cation density Can be significantly increased. The starting materials and catalysts used are very inexpensive compared to conventional vinylformamide or polyacrylamide starting materials, and after polymerization of vinylamine, they are polymerized as they are without separate separation steps to synthesize polyaniline, a water-soluble, water-soluble polymer . Here, synthesis of vinylamine monomers may be possible only by the first injection of sodium hydroxide and sodium hypochlorite. However, it is very difficult to synthesize vinylamine monomers by secondary addition of sodium hypochlorite in terms of vinylamine selectivity, degree of amination and charge density of polyvinylamine desirable.

In the polymerization of vinylamine monomers, azo initiators such as 2,2-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis [2- (2-imidazolin- Azobis [2- (2-imidazolin-2-yl) propane] disulfate dihydrate and 2,2'-azobis [N- Propionamidine] hydrate may be used alone or in combination.

On the other hand, the alkali catalyst content, monomer synthesis reaction temperature and polymerization reaction temperature affect the process efficiency and physical properties of monomers and copolymers to be synthesized, such as vinylamine selectivity and amination degree and charge density of polyvinylamine.

That is, the content of sodium hydroxide used as an alkali catalyst in the present invention is preferably 10 to 50 molar ratio, more preferably 20 to 40 molar ratio, relative to the acrylamide monomer, and the sodium hypochlorite content is 0.3 to 1.5 molar ratio relative to the acrylamide monomer , More preferably from 0.8 to 1.2 mole ratio. In the case of sodium hypochlorite, it is recommended to adjust the second input amount to 1.5 ~ 2.5 times the first input amount.

The reaction temperature may be in the range of -15 to 50 ° C in the synthesis of the vinylamine monomer. However, the higher the reaction temperature, the lower the degree of amination of vinylamine and the charge density of polyvinylamine. If the reaction temperature is too low The selectivity may be deteriorated. Therefore, the reaction temperature is more preferably -5 to 10 ° C.

Also, the reaction temperature may be 20 to 50 ° C in the case of polyvinylamine polymerization, but since the charge density of polyvinylamine may decrease as the reaction temperature is lowered, the reaction temperature is preferably 40 to 50 ° C desirable.

Hereinafter, the present invention will be described in more detail with reference to examples.

Example  One

1 is a view illustrating a continuous reaction process for producing polyvinylamine according to the present invention. (0.055 mol) of 2M sodium hypochlorite were added to a 2-liter reaction vessel, and 500 ml of distilled water was added thereto. The mixture was stirred at 400 rpm at 0 ° C for 2 hours Lt; / RTI > Then, 50 ml (0.1 mol) of 2M sodium hypochlorite was added thereto again and stirred for 10 hours. The amount of residual active chlorine ion was measured by the urethral titration method, and the reaction was stopped when the amount of active chlorine ion was insignificant. The amine-hydrochloric acid solution was passed through a column filled with an ion exchange resin (Amberlite IR-120) to obtain a vinylamine aqueous solution.

1,000 g (0.155 mol) of the synthesized vinylamine aqueous solution was heated to 45 캜, and then nitrogen was introduced for 1 hour. After dissolving 0.01 g of 2,2'-azobis (2-methylpropionamidine) dihydrochloride (V50) in 7 g of water and slowly adding it for 3 hours Lt; / RTI > Ammonium peroxide (0.02 g) and ammonium thiosulfate were added and stirred for 1 hour to obtain a polyvinylamine aqueous solution. Then, methanol was added to precipitate polyvinylamine, followed by filtration and drying to obtain polyvinylamine. The yield of polyvinylamine was 98%.

Example 2

In Example 1, vinylamine was synthesized and polyvinylamine was polymerized in the same manner as in Example 1, except that the vinylamine synthesis reaction temperature was adjusted to 10 ° C.

Example 3

In Example 1, vinylamine was synthesized and polyvinylamine was polymerized in the same manner as in Example 1, except that the reaction temperature for the vinylamine synthesis reaction was adjusted to 25 ° C.

Example 4

In Example 1, vinylamine was synthesized and polyvinylamine was polymerized in the same manner as in Example 1 except that the vinylamine synthesis reaction temperature was adjusted to 50 ° C.

Example 5

Vinylamine was synthesized and polyvinylamine was polymerized in the same manner as in Example 1, except that the amount of sodium hydroxide was adjusted to 4.5 mol in Example 1.

Example 6

Vinylamine was synthesized and polyvinylamine was polymerized in the same manner as in Example 1, except that the amount of sodium hydroxide was adjusted to 3.5 mol in Example 1.

Example 7

Vinylamine was synthesized and polyvinylamine was polymerized in the same manner as in Example 1, except that the amount of sodium hydroxide was adjusted to 3.0 mol in Example 1.

Example 8

Vinylamine was synthesized and polyvinylamine was polymerized in the same manner as in Example 1, except that the amount of sodium hypochlorite was adjusted to 0.145 mol (adjusted at a secondary charge) in Example 1.

Example 9

Vinylamine was synthesized and polyvinylamine was polymerized in the same manner as in Example 1, except that the amount of sodium hypochlorite was controlled to 0.135 mol (adjusted at the second injection amount) in Example 1.

Example 10

Vinylamine was synthesized and polyvinylamine was polymerized in the same manner as in Example 1, except that the amount of sodium hypochlorite was adjusted to 0.125 mol (adjusted at a secondary injection amount) in Example 1.

Comparative Example 1

5 g of polyacrylamide was dissolved in 95 g of deionized water at 70 캜 with stirring. 14.66 g of sodium hypochlorite aqueous solution (12.5%) and 2.07 g of sodium hydroxide (95%) were added to an aqueous solution of polyacrylamide and reacted at 0 ° C to synthesize polyvinylamine.

Comparative Example 2

5 g of polyacrylamide was dissolved in 95 g of deionized water at 70 캜 with stirring. 14.66 g of sodium hypochlorite aqueous solution (12.5%) and 2.07 g of sodium hydroxide (95%) were added to an aqueous solution of polyacrylamide and reacted at 50 ° C to synthesize polyvinylamine.

Comparative Example 3

3 g of polyvinylformamide was dissolved in 50 ml of deionized water at 70 ° C, and 0.5 g of 5% Pd / C was added thereto, followed by reaction at 120 ° C. Excess methanol was added to precipitate polyvinylamine, followed by filtration, followed by drying at 65 ° C in a dryer.

Test Example

The vinylamine and polyvinylamine synthesized according to the above Examples and Comparative Examples were measured for physical properties by the following method (Comparative Example was measured only for the degree of amination). The results are shown in Table 1 below.

[How to measure]

(1) Amine group concentration

Colloid titration method.

(2) Intrinsic viscosity and number average molecular weight

The polyvinylamine aqueous solution was prepared at a concentration of 0.1, 0.2, 0.3 and 0.4%, and the dropping time was measured at 25 ° C. using a Ubbelohde viscometer to calculate the intrinsic viscosity. The number average molecular weight was calculated from the following formula (H. Tanaka, J. Polym. Sci., Polym. Chem. Ed., 17, 1239, 1979) of the intrinsic viscosity and molecular weight shown.

[Equation 1]

Referring to the results of Examples 1 to 4, it can be seen that the lower the vinylamine synthesis reaction temperature is, the higher the degree of amineamine of vinylamine, the charge density, the intrinsic viscosity and the number average molecular weight of polyvinylamine are increased.

Also, referring to the results of Example 1 and Examples 5 to 7, it was found that as the sodium hydroxide amount was increased when acrylamide and sodium hypochlorite were equimolarly added at a vinylamine synthesis reaction temperature of 0 ° C, The charge density, intrinsic viscosity and number average molecular weight of the vinylamine are also increased.

Also, referring to the results according to Example 1 and Examples 8 to 10, as the amount of sodium hypochlorite increased at 0 ° C, the degree of amineamine vinylamine, charge density, intrinsic viscosity and number average It can be seen that the molecular weight also increases.

On the other hand, when polyacrylamide was used according to the conventional method, the degree of amination was relatively low, which was only 92% at a reaction temperature of 0 ° C (Comparative Example 1) The degree of amination has fallen to 75%.

On the other hand, when conventional polyvinylformamide is used (Comparative Example 3), there is a problem that the amination degree is high but it is burdensome to the manufacturing cost as described above.

According to the present invention, vinylamine synthesized by using sodium acrylate and sodium hypochlorite as starting materials and acrylamide monomer as a starting material can be used as a starting material and acrylic crosslinking agent in the synthesis of various derivatives, and polyvinylamine Is used as an additive used in the manufacture of specialty paper and can be used as a fiber surface treating agent so that the dye before fiber dyeing can be well fixed. Also, it has been studied as a material which improves electrolyte performance by forming a complex with a fluorine resin used as a polymer electrolyte, and is used as a surface treatment agent for converting the surface of a hydrophobic polymer film into a hydrophilic surface and a coating agent for enhancing durability of the film. Also, because of its high cation resin properties, it can be used as a metal ion adsorbent capable of adsorbing anionic metal ions, particularly iron ions and chromium ions. In addition, because of its high charge density, the copolymer with acrylamide can be more easily adsorbed in the wastewater and can be processed as a new coagulant. And is used as an adhesive for a laminate film, and a copolymer with polyvinyl alcohol is used as a barrier film for suppressing water and oxygen permeability. Also, it can be used as a gas separation membrane material to block carbon dioxide due to its strong ionic nature.

As such, the polyvinylamine produced according to the present invention is a new water-soluble polymer and has a high charge density. Therefore, it is expected that the demand for paper, fiber, film and film using water-soluble materials will be increased.

The preferred embodiments of the present invention have been described in detail above. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention Should be interpreted.

Claims (8)

In the method for producing polyvinylamine,
Acrylamid monomer is reacted with an alkali catalyst and water to perform Hoffman rearrangement to synthesize a vinylamine monomer and then polymerizing the vinylamine monomer to prepare polyvinylamine,
The alkali catalyst is sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl)
The above-mentioned vinylamine monomers are synthesized by secondary reaction of sodium hypochlorite (NaOCl) after sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) are firstly reacted to rearrange Hoffmann,
The sodium hydroxide (NaOH) is used in an amount of 10 to 50 molar ratio relative to the acrylamide monomer,
The sodium hypochlorite (NaOCl) is used in an amount of 0.3 to 1.5 molar ratio with respect to the acrylamide monomer,
Wherein the synthesis of the vinylamine monomer is carried out at a temperature of -5 to 10 占 폚. delete delete delete delete delete The method according to claim 1,
The polymerisation can be carried out in the presence of a base such as 2,2-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis [2- (2-imidazolin- Azobis [2- (2-imidazolin-2-yl) propane] dysulfate dihydrate and 2,2'-azobis [N- (2-carboxyl) 2-methylpropionamidine] Wherein at least one azo initiator selected from the group consisting of an azo initiator is used. 8. The method of claim 7,
Wherein the polymerization is carried out at a reaction temperature of 20 to 50 占 폚.

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