RU2560177C1 - Method of obtaining water-soluble polymers on quaternary salts of dimethylaminoethylmethacrylate base - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to highly molecular compounds, in particular to method of obtaining water-soluble polymers based on quaternary salts of dimethylaminoethylmethacrylate, which can be applied as flocculants, effective in purification of sewage water of different origin. Claimed is method of obtaining water-soluble polymers based on quaternary salts of dimethylaminoethylmethacrylate of general formula

, where R₁=-CH₃, -CH₂-CH₃ or -CH₂-C₆H₅; X^-=Cl^-, Br^-, ^-OSO₃CH₃, average weight molecular weight of synthesised polyelectrolytes is higher than 10⁶, with monomer being polymerised in water solution at 20°C, target product of polymerisation is extracted, purified by dialysis and dried lyophilically; method is characterised by the fact that sodium dodecylsulphate is additionally introduced into solution with molar ratio monomer:sodium dodecylsulphate equal 1-10:1, with radical initiator tret-buthylperoxypropanol-2 being applied as initiator, and monomer being polymerised in argon medium.

EFFECT: obtaining cation highly molecular polyelectrolyte, possessing reduced polydispersity.

6 ex, 1 tbl

Description

The invention relates to the chemistry of macromolecular compounds, in particular to a method for producing water-soluble polymers based on quaternary salts of dimethylaminoethyl methacrylate with the general formula

where R ₁ = —CH ₃ , —CH ₂ —CH ₃ or —CH ₂ —C ₆ H ₅ ; X ^- = Cl ^- , Br ^- , ^- OSO ₃ CH ₃ ,

which can be used as flocculants effective in wastewater treatment of various nature.

The relevance and prospects of developing methods for producing cationic polyelectrolytes in aqueous solutions is determined by the possibility of using aqueous solutions of polyelectrolytes obtained during polymerization in flocculation processes without polymer isolation, which, in turn, avoids contamination of purified water.

However, the use of an aqueous solution requires solving technological issues associated with the loss of fluidity in the polymerization process.

A known method of producing a cationic polymer in which the monomer is polymerized in an aqueous solution at a temperature of 70-150 ° C and a pH of 2-9.5 using a radical polymerization initiator selected from the group of alkali metal salts, alkaline earth metals, salts and salts ammonia, which are dispersed in the polymerization system (Patent US 4164612, IPC B01D 21/01, C08F 2/00, C08F 2/04, C08F 2/10, C08F 2/44, C08F 20/00, C08F 20/34, 14.08. 1979).

The disadvantage of this method is that the polymerization is carried out at high temperatures, and the resulting polymers have a high polydispersity.

A known method of producing polymers based on salts of Ν, Ν, Ν, Ν-trimethylmethacryloyloxyethylammonium by heating these salts to a temperature necessary and sufficient to obtain a homogeneous syrup in 5-6 wt.% Water, added based on the final mixture in an atmosphere that does not contain oxygen, with an adjustable pH value of 3.0-5.0 (Patent RU 2164921, IPC C08F 120/34, C02F 1/56, 04/10/2001).

The disadvantages of this method include the need for heating the system to dissolve the monomer and the high process temperature and the associated need for heat removal, as well as the high polydispersity of the resulting polymers.

A known method of producing poly-Ν, Ν, Ν, Ν-trimethylmethacryloyloxyethylammonium methyl sulfate by dissolving the monomer Ν, Ν, Ν, Ν-trimethylmethacryloyloxyethylammonium methyl sulfate in an aqueous-organic solution containing an acetate buffer with a pH of 4.5-5.5 in an inert gas atmosphere, and polymerization by heating at a ratio of water: solvent = 1: 0.05-2.0 (Patent RU 2088593, IPC C08F 2/06, C08F 120/34, 08/27/1997).

The disadvantages of the method include the use of organic solvents, a high polymerization temperature, the need to adjust the pH of the medium, as well as the high polydispersity of the resulting polymers.

A known method of obtaining a composition with a flocculating effect by dissolving Ν, Ν, Ν, N-trimethylmethacryloyloxyethylammonium methyl sulfate and sodium acetate in water, introducing acetic acid, adjusting the pH of the reaction mixture to 4.5-5.5, followed by removal of oxygen and polymerization by heating (Patent RU 2106370, IPC C08L 33/14, C08F 120/34, C08K 5/09, C02F 1/56, 03/10/1998).

The disadvantages of this method are the high polymerization temperature, the need to adjust the pH of the medium, as well as the high polydispersity of the resulting polymers.

A known method of producing poly-N, N-dimethylaminoethyl methacrylate sulfate by polymerization of Ν, Ν-dimethylaminoethyl methacrylate sulfate in an aqueous solution, when its concentration in an aqueous solution of 36.4-65.6 wt. and pH 1.2-3.5 in an inert gas at 20 ° C in the presence of a radical initiator - a redox system (Patent RU 1750183, IPC C08F 120/34, 05.20.1996).

The disadvantages of this method are the multicomponent initiating system, the need to adjust the pH of the medium, as well as the high polydispersity of the resulting polymers.

The closest is a method of producing polymethacryloyloxyethyltrimethylammonium methyl sulfate by polymerization of a monomer in an aqueous solution at 20 ° C in an inert gas in the presence of an initiating redox system with the introduction of cocatalyst into the initiating system and polymerization at a pH of 1.0-3.5 (RU Patent 1748420, IPC C08F 120/34, C08F 2/04, 05.20.1996).

The disadvantages of this method are the multicomponent initiating system, the need to control the pH of the medium, as well as the high polydispersity of the resulting polymers.

The objective of the invention is to provide a technologically advanced method for producing a water-soluble high molecular weight cationic polymer.

The technical result is a cationic high molecular weight polyelectrolyte having reduced polydispersity.

The technical result is achieved in a method for producing water-soluble polymers based on quaternary salts of dimethylaminoethyl methacrylate of the general formula

where R ₁ = —CH ₃ , —CH ₂ —CH ₃ or —CH ₂ —C ₆ H ₅ ; X ^- = Cl ^- , Br ^- , ^- OSO ₃ CH ₃ ,

the mass-average molecular weight of the synthesized polyelectrolytes is higher than 10 ⁶ , while the monomer is polymerized in an aqueous solution at 20 ° C, the polymerization product is isolated, purified by dialysis and freeze-dried, and sodium dodecyl sulfate is additionally introduced into the solution at a molar ratio of monomer: sodium dodecyl sulfate equal to 1-10: 1, the initiator is the radical initiator tert-butyl peroxypropanol-2, and the monomer is polymerized in argon.

The essence of the proposed method is the use of a surface-active component sodium dodecyl sulfate (SAS) in combination with tert-butyl peroxypropanol-2 initiator during polymerization of quaternary salts of dimethylaminoethyl methacrylate, and the initiation of the process using tert-butyl peroxypropanol-2 ensures the polymerization process without heating. In this case, the sodium dodecyl sulfate molecules in the solution form associates, electrostatically bind the monomer molecules and, orienting them on their surface, control the formation of the polymer. This control is manifested at the rate of polymer formation, the length of its chains, the chemical structure and isomerism of the monomer units, and the sequence of their addition. As a result, a polymer is formed with controlled molecular weight characteristics, including reduced polydispersity.

The use of tert-butyl peroxypropanol-2 (TBP) as the polymerization initiator makes it possible to obtain cationic polyelectrolytes (PE) with a high molecular weight (MM) while maintaining solubility in the absence of heating of the reaction mass.

In the framework of the stated ratios of monomer: surfactant equal to 1-10: 1, the formation of polymerization products is possible both in the form of a precipitate, and in the form of a concentrated polymer solution (gel), which are polyelectrolyte-surfactant associates.

и при больших углах рассеяния света $$\left(M_w^{\theta >90}\right)$$

, определенных методом статистического светорассеяния, существенно ниже, чем полидисперсность полиэлектролитов, полученных свободнорадикальной полимеризацией. Получение наиболее узкодисперсных полиэлектролитов $$(\raisebox{1ex}{$M_w^{0<90}$}\!\left/ \!\raisebox{-1ex}{$M_w^{0>90}$}\right.)\approx 1$$

возможно в условиях формирования осадка. Полимеры, полученные при мольном избытке мономера, имеют более высокие значения $$(\raisebox{1ex}{$M_w^{0<90}$}\!\left/ \!\raisebox{-1ex}{$M_w^{0>90}$}\right.)$$

, однако они остаются существенно ниже, чем отношение $$(\raisebox{1ex}{$M_w^{0<90}$}\!\left/ \!\raisebox{-1ex}{$M_w^{0>90}$}\right.)$$

для полимеров, полученных свободнорадикальной полимеризацией.The resulting polyelectrolytes were investigated for their polydispersity. The research results are shown in the table. The polydispersity of the obtained polyelectrolytes, calculated as the ratio of the mass-average molecular weights measured at small angles of light scattering $$\left(M_w^{\theta <90}\right)$$

and at large angles of light scattering $$\left(M_w^{\theta >90}\right)$$

determined by the method of statistical light scattering is significantly lower than the polydispersity of polyelectrolytes obtained by free radical polymerization. Obtaining the most finely dispersed polyelectrolytes $$(\raisebox{1ex}{$M_w^{0<90}$}\!\left/ \!\raisebox{-1ex}{$M_w^{0>90}$}\right.)\approx \mathrm{one}$$

possibly in conditions of sediment formation. Polymers obtained with a molar excess of monomer have higher values $$(\raisebox{1ex}{$M_w^{0<90}$}\!\left/ \!\raisebox{-1ex}{$M_w^{0>90}$}\right.)$$

however, they remain significantly lower than the ratio $$(\raisebox{1ex}{$M_w^{0<90}$}\!\left/ \!\raisebox{-1ex}{$M_w^{0>90}$}\right.)$$

for polymers obtained by free radical polymerization.

It is especially necessary to note that regardless of the nature of the monomer and the ratio of monomer / surfactant, the mass-average molecular weight of the synthesized polyelectrolytes remains higher than 10 ⁶ , which is unattainable with other methods of controlled polymer synthesis.

Example 1. A method of obtaining a water-soluble polymer based on Ν, Ν, Ν, Ν-trimethylmethacryloyloxyethylammonium methyl sulfate (DMAEMA-DMS)

1.8 g (0.006 mol) of DMAEMA-DMS are loaded into a 25 ml tube, 11.4 ml of distilled water are added to 1.8 g (0.006 mol) of sodium dodecyl sulfate. After complete dissolution of the monomer and surfactant, 0.25 ml of an aqueous initiator solution of tert-butyl peroxypropanol-2 with a concentration of 0.1 mol / L and 10 ml of water are added to the test tube. The resulting solution is transferred into an ampoule, the reaction mass is purged with argon for 10-15 minutes, after the ampoule is sealed and kept under normal conditions for 48 hours. As a result, associates of PE-SAS are formed in the form of a precipitate, which is filtered off and dried. In this form, the precipitate can be stored for a long time in a desiccator.

To isolate the desired polymerization product, a 3.5M NaCl solution is poured onto the resulting precipitate (based on 400 ml of solution per 1 g of precipitate) and the resulting mixture is kept for 3 days with periodic vigorous shaking. Then 4 g of BaCl ₂ are added, the solution is filtered through a paper filter, the filtrate is dialyzed to remove sodium chloride, the purified PE solution is frozen and freeze-dried. Dried PE is stored in a desiccator over P ₂ O ₅ .

The purity of the isolated water-soluble polymer based on DMAEMA-DMS is confirmed by elemental analysis.

The nitrogen content is 0.42 mol%, the chlorine content is 0.39 mol%. The isolated polymers do not contain sulfur, which means that they do not contain surfactants, and in the process of isolating the obtained polymer, the dodecyl sulfate ions are quantitatively replaced by chlorine ions.

The mass-average molecular weight of the obtained polymer is 1.01 · 10 ⁶ .

Example 2. A method of obtaining a water-soluble polymer based on N, N-dimethyl-N-ethyl-N-methacryloyloxyethylammonium bromide (DMAEMA-BE)

The method is carried out analogously to example 1 using 0.7 g (0.003 mol) of DMAEMA-BE and 0.7 g (0.0024 mol) of dodecyl sulfate. Quantitatively isolated and dried PE is stored in a desiccator over P ₂ O ₅ .

The purity of the selected water-soluble polymer based on DMAEMA-BE is confirmed by elemental analysis.

The nitrogen content is 0.42 mol%, the chlorine content is 0.39 mol%. The selected polymers do not contain sulfur, which means that they do not contain surfactants, and in the process of isolating the polymers, dodecyl sulfate ions are quantitatively replaced by chlorine ions. The mass-average molecular weight of the obtained polymer is 1.43 · 10 ⁶ .

Example 3. A method of obtaining a water-soluble polymer based on [N-benzyl-N, N-dimethyl-N- (methacryloyloxyethyl)] ammonium chloride (DMAEMA-BH)

The method is carried out analogously to example 1 using 14.2 g (0.05 mol) of DMAEMA-BH and 2.9 g (0.01 mol) of sodium dodecyl sulfate. Quantitatively isolated and dried PE are stored in a desiccator over P ₂ O ₅ .

The purity of the isolated water-soluble polymer based on DMAEMA-BH is confirmed by elemental analysis.

The nitrogen content is 0.42 mol%, the content of chlorine is 0.39 mol%. The selected polymers do not contain sulfur, which means that they do not contain surfactants, and in the process of isolating the polymers, dodecyl sulfate ions are quantitatively replaced by chlorine ions. The mass-average molecular weight of the obtained polymer is 1.37 · 10 ⁶ .

Example 4. A method of obtaining a water-soluble polymer based on N, N, N, N-trimethylmethacryloyloxyethylammonium methyl sulfate (DMAEMA-DMS)

The method is carried out analogously to example 1 using 7.1 g (0.025 mol) of DMAEMA-DMS and 0.7 g (0.0024 mol) of sodium dodecyl sulfate. As a result, PE-surfactant associates are formed in the form of a gel (which is a highly concentrated polymer solution). In this form, the gel can be stored for a long time.

To isolate the desired polymerization product, 3.5 M NaCl solution is poured onto the gel obtained (based on 100 ml of solution per 1 g of gel) and the resulting solution is stirred on a magnetic stirrer for 3 days, the solution is filtered through a paper filter, the filtrate is dialyzed to remove sodium chloride , the purified PE solution is frozen and freeze-dried. Dried PE is stored in a desiccator over P ₂ O ₅ .

The purity of the isolated water-soluble polymer based on DMAEMA-DMS is confirmed by elemental analysis. The nitrogen content is 0.42 mol%, the chlorine content is 0.39 mol%. The selected polymers do not contain sulfur, which means that they do not contain surfactants, and in the process of isolating the obtained polymer, the dodecyl sulfate and methyl sulfate ions are quantitatively replaced by chlorine ions. The mass-average molecular weight of the obtained polymer is 1.36 · 10 ⁶ .

Example 5. A method of obtaining a water-soluble polymer based on N, N-dimethyl-N-ethyl-N-methacryloyloxyethylammonium bromide (DMAEMA-BE)

The method is carried out analogously to example 1 using 10.7 g (0.04 mol) of DMAEMA-BE and 1.4 g (0.0049 mol) of sodium dodecyl sulfate. As a result, PE-surfactant associates are formed in the form of a gel (which is a highly concentrated polymer solution). In this form, the gel can be stored for a long time.

The selection of the target polymerization product is carried out analogously to example 4. Selected quantitatively and dried PE is stored in a desiccator over P ₂ About ₅ .

The purity of the selected water-soluble polymer based on DMAEMA-BE is confirmed by elemental analysis. The nitrogen content is 0.42 mol%, the content of chlorine is 0.39 mol%. The isolated polymers do not contain sulfur, which means that they do not contain surfactants, and in the process of polymer isolation, the bromine and dodecyl sulfate ions are quantitatively replaced by chlorine ions. The mass-average molecular weight of the obtained polymer is 3.29 · 10 ⁶ .

Example 6. A method of obtaining a water-soluble polymer based on [N-benzyl-N, N-dimethyl-N- (methacryloyloxyethyl)] ammonium chloride (DMAEMA-BH)

The method is carried out analogously to example 1 using 17.7 g (0.06 mol) of DMAEMA-BH and 1.4 g (0.005 mol) of sodium dodecyl sulfate. As a result, PE-surfactant associates are formed in the form of a gel (which is a highly concentrated polymer solution). In this form, the gel can be stored for a long time.

The selection of the target polymerization product is carried out analogously to example 4. Selected quantitatively and dried PE is stored in a desiccator over P ₂ About ₅ .

The purity of the isolated water-soluble polymer based on DMAEMA-DMS is confirmed by elemental analysis. The nitrogen content is 0.42 mol%, the chlorine content is 0.39 mol%. The selected polymers do not contain sulfur, which means that they do not contain surfactants, and in the process of isolating the polymers, dodecyl sulfate ions are quantitatively replaced by chlorine ions. The mass-average molecular weight of the obtained polymer is 1.51 · 10 ⁶ .

Thus, the proposed technological method of obtaining allows to obtain water-soluble cationic high molecular weight polyelectrolytes based on quaternary salts of dimethylaminoethyl methacrylate, which have a reduced polydispersity.

Claims (1)

The method of obtaining water-soluble polymers based on quaternary salts of dimethylaminoethyl methacrylate of the General formula

where R ₁ = —CH ₃ , —CH ₂ —CH ₃ or —CH ₂ —C ₆ H ₅ ; X ^- = Cl ^- , Br ^- , ^- OSO ₃ CH ₃ ,
the mass-average molecular weight of the synthesized polyelectrolytes is higher than 10 ⁶ , while the monomer is polymerized in an aqueous solution at 20 ° C, the polymerization product is isolated, purified by dialysis and freeze-dried, characterized in that sodium dodecyl sulfate is additionally introduced into the solution at a molar ratio of monomer: sodium dodecyl sulfate equal to 1-10: 1, the initiator is the radical initiator tert-butyl peroxypropanol-2, and the monomer is polymerized in argon.