RU2164921C2 - Method of preparing polymers based on n,n,n,n- trimethylmethacroyloxy ethylammonium salts - Google Patents

Abstract

FIELD: chemistry of polymers. SUBSTANCE: described is method of polymers based on N,N,N,N-trimethylmethacroyloxy ethylammonium salts by heating said salts in atmosphere containing no oxygen in water- containing medium with controllable pH value, 5-6 wt.% of water per final mixture is added to N,N,N,N-trimethylmethacroyloxy ethylamonium salt, and the whole is heated to temperature to form homogeneous syrup, and pH value is thereafter adjusted at to 3.0-5.0, and polymerization is carried out during heating at this temperature. Method makes it possible to obtain readily grindable water-soluble high molecular weight cationic polymer in the presence of small amounts of water without heating stage at elevated temperature. EFFECT: more efficient preparation method. 4 cl, 6 ex

Description

где

Такие полимеры нашли использование в качестве флокулянтов для очистки сточных вод различного происхождения, в процессах водоподготовки, для интенсификации бумажного производства, а также в качестве загустителя, кондиционера, антистатика.The invention relates to a method for producing polymers based on salts of such a monomer as N, N, N, N-trimethylmethacryloyloxyethylammonium with the formula

Where

Such polymers have been used as flocculants for wastewater treatment of various origins, in water treatment processes, for the intensification of paper production, as well as as a thickener, conditioner, antistatic agent.

где
R₁ =-H или CH₃:R₂=-CH₂CH₂ - или -CH₂CH(OH)CH₂-;
R₃ и R₄ = -CH₃ или -CH₂CH₂; R₅ = -C_nH_2n+1, при n - целое число от 0 до 4; -CH₂C₆H₅ или -CH₂ COOH;

2. Полимеризуют вышеперечисленные мономеры с выделением и очисткой после из синтеза кватернизацией N,N-диметиламино-алкил(мет)акрилатов.A known method of producing water-soluble cationic polymers / 1 /. In accordance with the patent formula, the method is implemented by a combination of the following essential features:
1. Polymerized vinyl monomers of the General formula

Where
R ₁ = —H or CH ₃ : R ₂ = —CH ₂ CH ₂ - or —CH ₂ CH (OH) CH ₂ -;
R ₃ and R ₄ = —CH ₃ or —CH ₂ CH ₂ ; R ₅ = —C _n H _{2n + 1} , when n is an integer from 0 to 4; -CH ₂ C ₆ H ₅ or -CH ₂ COOH;

2. The above monomers are polymerized with isolation and purification after synthesis from quaternization of N, N-dimethylamino-alkyl (meth) acrylates.

 3. Either the indicated monomer itself is polymerized, or mixed with another vinyl monomer, the amount of which cannot exceed 25 wt.% Of the total amount of monomers, otherwise such a large amount of heat is released that it is impossible to efficiently remove, which makes the polymerization reaction unregulated .

 4. The polymerization is carried out in the presence of radical initiators.

 5. The polymerization is carried out in the presence of 7-18 wt.% Water, a decrease in the amount of which to 6% leads to a sharp drop in the molecular weight and conversion.

6. The polymerization is carried out so that the final temperature of the system reaches 110 ^o - 150 ^o C.

 7. The polymerization is carried out at a pH of an aqueous medium of 3-8.

 8. The polymerization is carried out in an atmosphere that does not contain oxygen.

A decrease in the water content below 7%, in addition to the indicated consequences, also leads to the fact that the polymerization is uneven in volume due to the presence in the system of a large amount of monomer, which is not dissolved and is in the crystalline phase. In this case, both an insoluble fraction and a low molecular weight product are formed. In addition, regardless of the chemical nature of the radical initiators, be it redox systems (ferrous salts — hydrogen peroxide or ascorbic acid — alkali metal persulfate) or water-soluble azo compounds, the reaction polymerization mixture must be heated to 110 ^o -150 ^o C, otherwise it decreases the yield of the target product and the amount of residual monomer increases.

 In the known method, as the target product, a polymer is obtained with a viscosity of 1% aqueous solution up to 7000 cf (Brookfield viscometer, this corresponds to a characteristic viscosity of 4-5 dl / g or a molecular weight of not more than 4.5 - 5 million D).

2. К соли указанной структуры добавляют 5-6 мас.% воды в расчете на конечную смесь.The objective of the invention was to obtain easily crushed water-soluble high molecular weight cationic polymer in the presence of small amounts of water without a heating step at elevated temperatures. This problem was solved by a method for producing polymers based on the salt of N, N, N, N-trimethylmethacryloyloxyethylammonium, for example, benzenesulfonate, methyl sulfate, and the like. The method is implemented by a combination of the following essential features:
1. The polymerization of salts of N, N, N, N-trimethylmethacryloyloxyethylammonium of the general formula according to the scheme

2. To the salt of this structure add 5-6 wt.% Water in the calculation of the final mixture.

 3. The mixture is heated to a temperature necessary and sufficient to form a homogeneous syrup.

 3. The resulting mixture is heated at the same temperature in an oxygen-free atmosphere.

 4. The polymerization is carried out at a pH of 3.0-5.0.

5. Homogenization of water in benzenesulfonate and polymerization of the mixture is carried out at 70 ^o -75 ^o C.

6. Homogenization of water in methyl sulfate and polymerization of the mixture is carried out at 45 ^o - 50 ^o C.

 Distinctive features of the claimed method are signs 1, 2, 5, 6.

 An analysis of the known level of science and technology did not allow us to find solutions that are identical to those claimed by the combination of essential features.

 This indicates the novelty of the solution.

 The analysis also did not allow finding published solutions in which a system containing monomers with the addition of 5-6 wt.% Water would be used for polymerization. In the inventive method, it was possible to obtain a homogeneous polymer with a high molecular weight during polymerization in the presence of such an amount of water that cannot provide, from the point of view of common sense and existing practice, the complete dissolution of the quaternized monomer and the production of a homogeneous monomer solution, which is necessary for the polymerization.

 However, under the stated conditions, it was possible to obtain an almost dry target product in the form of an easily crushed and highly soluble polymer with an intrinsic viscosity of 6.5 - 7.5 dl / g or with an MM of up to 9 ppm.

 Thus, the proposed method is based on the previously unknown and not obvious from the known properties of similar in structure monomers ability of such monomers as N, N, N, N-trimethylmethacryloyloxyethyl ammonium salts (for example, benzenesulfonate, methyl sulfate, etc.) to form a uniformly distributed system in the presence of 5-6 wt.% water in the polymerization conditions found.

Finding a new relationship "composition - property" confirms the conformity of the claimed proposal to the criterion of "inventive step"
The structure of the polymers obtained by the claimed method was established by NMR spectroscopy, which confirmed the safety during polymerization of all functional groups in the monomer except vinyl. Elemental analysis showed the preservation of the composition during polymerization.

 The flocculating properties of the obtained polymers were studied according to the accepted method: the rate of complete precipitation of a 0.1% suspension of kaolin (particle size 0.5-40 μm) in water at room temperature was determined. For this, 0.5 g of kaolin is suspended in 500 ml of water with stirring for 30-60 seconds. Almost complete clarification in a measured 500 ml cylinder without adding any flocculants occurs after 48 hours. When 10 ml of 0.1 wt.% Aqueous solution of PERCOL flocculant (Germany) is added, the precipitation of the suspension begins after 1 min and ends after 15 min. Under the same conditions, the addition of polymer flocculants based on the salt of poly-N, N, N / N-trimethylmethacryloyloxyaminoethylammonium, the production method of which is presented in the present description, leads to the onset of precipitation one minute after the addition of the flocculant and ends after 10-15 minutes depending on the MM polymer flocculant.

 For a better understanding of the essence, as well as to confirm compliance of the claimed invention with the criterion of "industrial applicability", we give examples of specific implementation of the proposal, while noting that such examples cannot exhaust the essence of the invention.

Example 1. In a 0.25 L glass beaker, 66.4 g of N, N, N, N-trimethylmethacryloyloxyethylammonium benzenesulfonate and 4.2 g of water are charged (the water content of the mixture is 6 wt.%, Based on the final mixture). The beaker was placed in a water bath and the monomer was dissolved with stirring at 70 ^° C. After complete dissolution, a thick, clear syrup is obtained. It is purged with a stream of nitrogen to remove oxygen. Then, in a stream of nitrogen, the syrup is acidified with 50% sulfuric acid to pH 3 and poured into a metal cuvette, previously heated to the same temperature. The cuvette with the polymer solution is placed in a thermostat and incubated for 20 hours at 70 ^° C in a nitrogen atmosphere. The resulting polymer is separated after cooling and is easily crushed mechanically. The yield of a dry, free flowing polymer with a particle size of less than 2 mm and with a residual moisture content of about 4% is 68.5 g, i.e. 94%.

The crushed polymer easily dissolves in water with vigorous stirring and heating to 50 ^o - 60 ^o C.

The viscosity of a 0.1% aqueous solution at 20 ^° C. 43 cps, which corresponds to a characteristic viscosity of 7 dl / g (1% NaNO ₃ solution, 20 ^° C.) or MM about 8 ppm.

Example 2. Performed under the conditions of example 1, but the polymerization temperature of 75 ^o C, the exposure time at this temperature is 15 hours. The water content in the reaction mixture is 5%. The characteristics of the obtained polymer are similar to those shown in example 1. The residual water content of 3%.

Example 3. Performed under the conditions of example 1, but the amount of water introduced is 4 wt. % To obtain a reaction mixture homogeneous in transparency, the polymerization temperature had to be raised to 85 ^° C. The resulting polymer was partially crosslinked, contains a low molecular weight fraction, and is not fully soluble in water.

Example 4. Under the conditions of Example 1, 46 g of the sulfomethyl salt of N, N, N, N-trimethylmethacryloyloxyethylammonium and 2.9 g of water (6 wt.%) Are heated at 50 ^° C. After being blown with a stream of nitrogen and acidified to pH 5.0, they are heated at a temperature of 50 ^o C for 20 hours. After cooling to room temperature, the polymer is separated from the polymerization cell and easily crushed mechanically. Yield 46.0 g or 96% (of theory) with a water content of 4.5%. The intrinsic viscosity is 7.5 dl / g, which corresponds to an MM value of about 9 million D.

Example 5. The polymer is obtained under the conditions of example 4 at a water content of 5%, at pH 4.5 and at a temperature of 45 ^o C. The yield of the target polymer 95% at a water content of 3.5%. The intrinsic viscosity is 6.5 dl / g, which corresponds to an MM value of about 7 million D.

Example 6. The polymer is obtained under the conditions of example 4 with a water content of 4%. To obtain a visually homogeneous monomer mixture, heating was required to 65 ^o C.

 The result is a partially crosslinked product containing a low molecular weight fraction.

 An analysis of the obtained examples shows that under the stated conditions a polymer product is obtained that meets all the requirements of the problem being solved.

Deviation from the stated conditions leads to the synthesis of polymers that differ in their properties from the target product:
1. The reduction of the monomer content in the reaction mixture to 80-88% leads to the production of an aqueous gel with increased stickiness and the inability to grind without additional drying.

 2. Increasing the monomer content to 96-99% makes it difficult to obtain a homogeneous monomer solution, which leads to heterogeneity of the polymerized mixture with the formation of a partially crosslinked product containing a low molecular weight fraction.

3. Reducing the polymerization temperature to 35 ^o - 40 ^o C leads to a significant increase in polymerization time and lower yield for methyl sulfate salt and the inability to obtain a homogeneous mixture in the case of benzenesulfonate salt.

4. Raising the homogenization temperature to 85 ^o C in the case of benzenesulfonate salt and up to 65 ^o C in the case of methyl sulfate salt significantly reduces the time required for blowing off oxygen with a nitrogen stream and for setting pH, since polymerization begins to take place at the same time and a partially crosslinked product forms.

List of sources of information
1. The patent of Germany N 2621456, IPC: 2 C 08 A 2/34, 1976.

Claims (4)

 1. A method of producing polymers based on salts of N, N, N, N-trimethylmethacryloyloxyethylammonium by heating these salts in an oxygen-free atmosphere in an aqueous medium with a controlled pH, characterized in that the salt N, N, N, N- trimethylmethacryloyloxyethylammonium is added 5-6 wt.% calculated on the final mixture and heated to a temperature necessary and sufficient to obtain a homogeneous syrup, then set the pH value to 3.0 - 5.0, and carry out the polymerization by heating at the same temperature.  2. The method according to claim 1, characterized in that as salts of N, N, N, N-trimethylmethacryloyloxyethylammonium take salts such as benzenesulfonate, methyl sulfate. 3. The method according to claim 1, characterized in that the homogenization of water in N, N, N, N-trimethylmethacryloyloxyethylammonium benzenesulfonate and subsequent polymerization is carried out at 70 - 75 ^o C. 4. The method according to claim 1, characterized in that the homogenization of water in methyl sulfate N, N, N, N-trimethylmethacryloyloxyethylammonium and subsequent polymerization is carried out at 45 - 50 ^o C.