PL243064B1 - New ionic liquids with alkyl (carbosymethyl) dimethylammonium cation and bis (2-ethylhexyl) phosphate anion, method of preparation and use as degreasing agents for work surfaces - Google Patents

Abstract

The subject of the invention are new ionic liquids with an alkyl(carboxymethyl)dimethylammonium cation and a bis(2-ethylhexyl)phosphate anion of formula 1, where R is a methyl to decyl substituent. The application also includes a method for obtaining the above substances, which consists in dissolving alkyl(carboxymethyl)dimethylammonium chloride in methanol or ethanol and subjecting it to an exchange reaction with sodium bis(2-ethylhexyl)phosphate in a molar ratio of chloride to sodium salt of 1:1 , at a temperature of 20 to 35°C, preferably 25°C, then the inorganic by-product is filtered off, then the product is dissolved in acetone to remove the residual inorganic salt, the precipitate is filtered off, and the solvent is evaporated from the product and dried in at 70°C. The subject of the application is also the use of new ionic liquids with an alkyl(carboxymethyl)dimethylammonium cation as washing agents.

Description

Description of the invention

The subject of the invention are new ionic liquids with alkyl(carboxymethyl)dimethylammonium cation and bis(2-ethylhexyl)phosphate anion, method of preparation and use as degreasing agents for working surfaces.

The modern world is characterized by scientific and technical progress. As a result of the growing demand for everyday products, such as dyes, fuel, plant protection products, there is an increasing threat to the natural environment. Therefore, solutions are sought to minimize this negative impact. One of the proposals are ionic liquids (ILs). These compounds consist of an organic cation and an inorganic or organic anion. Their specific ionic structure is the reason why they melt at a temperature lower than 100°C. There are many possibilities of combining cations and anions, which allow to obtain compounds with many interesting properties, e.g. low vapor pressure, non-flammability or interfacial activity.

Ionic liquids are a large group of compounds, which include surface active ionic liquids (SAILs). These are compounds with an amphiphilic structure capable of forming micelles in an aqueous environment and lowering the surface tension between a liquid substance and a specific outer layer. The fact that SAILs contain a hydrophilic and hydrophobic group in their structural structure affects their wetting, emulsifying and foaming properties. Surface-active compounds, thanks to their properties, have been used in many industries, e.g. in the production of washing and cleaning agents, and the synthesis of new SAILs is the goal of intensive research for many research centers.

The choice of both ions was related to their physicochemical properties and their impact on the environment and humans. The alkyl(carboxymethyl)dimethylammonium cation is a betaine derivative which is a naturally occurring compound. From the available literature data, alkylbetaine chlorides are used, among others, in cleaning agents, which makes them safe for humans and the environment. On the other hand, the choice of anion was dictated by good surface properties, which makes it possible to increase the effectiveness in degreasing agents for working surfaces.

The essence of the invention are new ionic liquids with an alkyl(carboxymethyl)dimethylammonium cation and a bis(2-ethylhexyl)phosphate anion of formula 1, where R is a methyl to decyl substituent.

Examples of these types of compounds are:

• decyl(carboxymethyl)dimethylammonium bis(2-ethylhexyl)phosphate, • octyl(carboxymethyl)dimethylammonium bis(2-ethylhexyl)phosphate, • hexyl(carboxymethyl)dimethylammonium bis(2-ethylhexyl)phosphate, • bis(2-ethylhexyl)phosphate butyl(carboxymethyl)dimethylammonium, • (carboxymethyl)trimethylammonium bis(2-ethylhexyl)phosphate.

The essence of the invention is also a method for obtaining new adjuvants in the form of ionic liquids with an alkyl(carboxymethyl)dimethylammonium cation, characterized in that the alkyl(carboxymethyl)dimethylammonium chloride is dissolved in methanol or ethanol and subjected to an exchange reaction with bis(2-ethylhexyl)phosphate sodium chloride to sodium salt molar ratio 1:1, at a temperature of 20 to 35°C, preferably 25°C, then the inorganic by-product is filtered off, then the product is dissolved in acetone to remove residual inorganic salt, the precipitate is filtered the solvent is evaporated from the product and dried at 70°C.

The essence of the invention is also the use of new ionic liquids with an alkyl(carboxymethyl)dimethylammonium cation as agents for degreasing working surfaces. Preferably, the new ionic liquids with the alkyl(carboxymethyl)dimethylammonium cation are used in the form of an aqueous solution with a concentration of at least 0.05%, or in the form of a hydroalcoholic solution with a concentration of at least 0.05%.

Thanks to the application of the solution according to the invention, the following technical and economic effects were obtained:

• ionic liquids containing an alkyl(carboxymethyl)dimethylammonium cation were synthesized, • the developed methods of synthesis run with high yields of over 89%, • the obtained salts are highly viscous liquids at ambient temperature, which allows them to be classified as ionic liquids, • synthesized ionic liquids have an immeasurable vapor pressure above their surface, • obtained ionic liquids show thermal stability in a wide range of temperatures, • obtained new compounds show surface activity, • synthesized compounds are used as degreasing agents for working surfaces.

The method of obtaining ionic liquids with an alkyl(carboxymethyl)dimethylammonium cation is illustrated in the following examples:

Example I

Method for obtaining decyl(carboxymethyl)dimethylammonium bis(2-ethylhexyl)phosphate

0.01 mol of decyl(carboxymethyl)dimethylammonium bromide was introduced into a flask containing 30 cm ³ of ethanol. Then, 0.01 mol of sodium bis(2-ethylhexyl)phosphate was added with constant stirring. Stirring was continued for 15 min at 30°C, after which the solvent was evaporated from the mixture. The product was purified by precipitation of the inorganic salt in acetone. The precipitate was filtered off, and acetone was evaporated from the reaction product. Then, the obtained ionic liquid was subjected to vacuum drying at 70°C. The yield of the reaction was 92%.

The performed proton and carbon nuclear magnetic resonance spectra allowed to confirm the structure of the product;

^1H NMR (CD3OD) δ [ppm] = 0.91 (t, 15H); 1.31(m, 30H); 1.53 (m, 2H); 1.77 (m, 2H); 3.30 (s, 6H); 3.59 (m, 2H); 3.82 (m, 4H); 4.31 (s, 2H).

^13C NMR (CD3OD) δ [ppm] = 11.5(2C), 14.5(4C), 20.3, 23.8(2C), 24.1(2C), 24.6(2C), 25.3, 29.1 (2C), 29.5 (2C) , 30.8(2C), 31.9, 41.7(2C), 54.2(2C), 62.3, 64.7, 69.5(2C), 168.2.

CHN elemental analysis for C30H64NO6P (Mmol = 565.46 g/mol): calculated values (%): C = 63.68; H=11.44; N=2.48; measured values (%): C = 63.22; H=11.08; N = 2.11.

Example II

Method for obtaining octyl(carboxymethyl)dimethylammonium bis(2-ethylhexyl)phosphate

0.01 mol of octyl(carboxymethyl)dimethylammonium chloride was introduced into a flask containing 30 cm ³ of methanol. Then, 0.01 mol of sodium bis(2-ethylhexyl)phosphate was added with constant stirring. Stirring was continued for 15 min at 35°C, after which the solvent was evaporated from the mixture. The product was purified by precipitation of the inorganic salt in acetone. The precipitate was filtered off, and acetone was evaporated from the reaction product. Then, the obtained ionic liquid was subjected to vacuum drying at 70°C. The yield of the reaction was 90%.

The performed proton and carbon nuclear magnetic resonance spectra allowed to confirm the structure of the product:

^1H NMR (CD3OD) δ [ppm] = 0.91 (t, 15H); 1.32 (m, 26H); 1.53 (m, 2H); 1.77 (m, 2H); 3.31 (s, 6H); 3.59 (m, 2H); 3.84 (m, 4H); 4.30 (s, 2H).

^13C NMR (CD3OD) δ [ppm] = 11.5(2C), 14.5(4C), 20.3, 23.8(2C), 24.1(2C), 24.6(2C), 25.3, 29.1 (2C), 30.8 (2C) , 31.9, 41.7(2C), 54.2(2C), 62.3, 64.7, 69.5(2C), 168.2.

CHN elemental analysis for C28H60NO6P (Mmol = 537.42 g/mol): calculated values (%): C = 62.54; H=11.25; N=2.60; measured values (%): C = 62.15; H=11.61; N = 2.23.

Example III

Method for obtaining hexyl(carboxymethyl)dimethylammonium bis(2-ethylhexyl)phosphate

0.01 mole of hexyl(carboxymethyl)dimethylammonium bromide was introduced into a flask containing 30 cm ³ of ethanol. Then, 0.01 mol of sodium bis(2-ethylhexyl)phosphate was added with constant stirring. Stirring was continued for 15 min at 20°C, after which the solvent was evaporated from the mixture. The product was purified by precipitation of the inorganic salt in acetone. The precipitate was filtered off, and acetone was evaporated from the reaction product. Then, the obtained ionic liquid was subjected to vacuum drying at 70°C. The yield of the reaction was 89%.

The performed proton and carbon nuclear magnetic resonance spectra allowed to confirm the structure of the product:

^1H NMR (CD3OD) δ [ppm] = 0.90 (t, 15H); 1.31 (m, 22H); 1.54 (m, 2H); 1.77 (m, 2H); 3.30 (s, 6H); 3.59 (m, 2H); 3.83 (m, 4H); 4.31 (s, 2H).

^13C NMR (CD3OD) δ [ppm] = 11.5(2C), 14.5(4C), 20.3, 23.8(2C), 23.9, 24.1(2C), 24.6(2C), 30.8 (2C), 31.5, 41.7 ( 2C), 54.2(2C), 62.3, 64.7, 69.5(2C), 168.2.

CHN elemental analysis for C26H56NO6P (Mmol = 509.38 g/mol): calculated values (%): C = 61.27; H=11.07; N=2.75; measured values (%): C = 61.66; H=11.47; N=2.43.

Example IV

Method for obtaining butyl(carboxymethyl)dimethylammonium bis(2-ethylhexyl)phosphate

0.01 mole of butyl(carboxymethyl)dimethylammonium chloride was introduced into a flask containing 30 cm ³ of methanol. Then, 0.01 mol of sodium bis(2-ethylhexyl)phosphate was added with constant stirring. Stirring was continued for 15 min at 30°C, after which the solvent was evaporated from the mixture. The product was purified by precipitation of the inorganic salt in acetone. The precipitate was filtered off, and acetone was evaporated from the reaction product. Then, the obtained ionic liquid was subjected to vacuum drying at 70°C. The yield of the reaction was 89%.

The performed proton and carbon nuclear magnetic resonance spectra allowed to confirm the structure of the product:

^1H NMR (CD3OD) δ [ppm] = 0.91 (t, 15H); 1.31 (m, 18H); 1.53 (m, 2H); 1.77 (m, 2H); 3.30 (s, 6H); 3.59 (m, 2H); 3.82 (m, 4H); 4.31 (s, 2H).

^13C NMR (CD3OD) δ [ppm] = 11.5(2C), 14.5(4C), 20.3, 23.8(2C), 24.1(2C), 24.6(2C), 30.8 (2C), 41.7 (2C), 54.2 (2C), 62.3, 64.7, 69.5 (2C), 168.2.

CHN elemental analysis for C24H52NO6P (Mmol = 481.35 g/mol): calculated values (%): C = 59.85; H=10.88; N=2.91; measured values (%): C = 59.46; H=10.48; N = 2.53.

Example V

Method for obtaining bis(2-ethylhexyl)phosphate (carboxymethyl)trimethylammonium

In the flask, 0.01 mol of (carboxymethyl)trimethylammonium chloride was dissolved in 30 cm ³ of ethanol. Then 0.01 mol of sodium bis(2-ethylhexyl)phosphate was added. The exchange reaction was carried out at 35°C with vigorous stirring. The butanol-insoluble inorganic salt was filtered off, and then the ethanol was evaporated in a vacuum evaporator. The resulting mixture was dissolved in 30 cm ³ of acetone. The precipitate was separated and the solvent was evaporated. The reaction product was dried in an oven under reduced pressure at 70°C. The yield of the reaction was 90%.

The performed proton and carbon nuclear magnetic resonance spectra allowed to confirm the structure of the product:

^1H NMR (CD3OD) δ [ppm] = 0.91 (m, 12H); 1.32 (m, 16H); 1.53 (m, 2H); 3.30 (s, 9H); 3.82 (m, 4H); 4.24 (s, 2H).

^13C NMR (CD3OD) δ [ppm] = 11.5 (2C), 14.5 (2C), 24.1 (2C), 24.6 (2C), 30.2 (2C), 33.5 (2C), 41.7 (2C), 54.3 (3C) ), 64.9, 69.3 (2C), 167.6.

CHN elemental analysis for C21H46NO6P (Mmol = 439.31 g/mol): calculated values (%): C = 57.38; H=10.55; N=3.19; measured values (%): C = 57.77; H=10.96; N = 3.58.

Application example

In order to use synthesized ionic liquids in the form of surface-active compounds, water or water-alcohol solutions should be prepared with concentrations ranging from 0.31 to 2.15 mmol/dm ³ in accordance with Table 1. Then, the previously prepared surfaces were washed with the prepared solutions. fat was present and their effectiveness in this respect was determined. In addition, the value of surface tension was measured using the hanging drop method, which was the basis for determining the parameters: critical micellation concentration (CMC) and surface tension in CMC. However, using the sessile drop method, the values of the contact angle at the interface of three phases, i.e. liquid-solid-gas, were determined. This parameter allows to determine the range of hydrophobicity or hydrophilicity of a given surface. The sedentary drop method is based on the Youn g-Laplace equation and the proper matching of the drop image according to its shape and edge. The wetted material was paraffin.

Application:

The determined parameters made it possible to determine the concentrations at which the synthesized ionic liquids act most effectively as agents for degreasing working surfaces.

Table 1 presents the values of the surface tension at CMC, the contact angle, as well as the values of the critical micellation concentration for the tested compounds.

PL 243064 B1

Table 1. Summary of surface activity for synthesized ionic liquids in the form of aqueous solutions

No Ionic liquid Surface tension in CMC [mN/m] CMC (mmol/ ^dm3 ) contact angle ['] 1 Butyl(carboxymethyl)dimethylammonium bis(2-ethylhexyl)phosphate 37.9 2.15 82.5 2 bis(2-ethylhexyl)phosphorus (carboxymethyl)trimethylammonium 40.1 1.48 77.5 3 4... .... decyl[carboxymethyl]dimethylammonium bis(2-ethylhexyl)phosphate 28.0 0.31 49.0

The tested ionic liquids with the alkyl(carboxymethyl)dimethylammonium cation are included in the group of compounds with interfacial properties due to the effectiveness of reducing the surface tension. The best interfacial properties are distinguished by decyl(carboxymethyl)dimethylammonium bis(2-ethylhexyl)phosphate. In relation to the other analyzed ionic liquids, this compound lowers the surface tension using the smallest amount of surfactant.

Claims (5)

1. New ionic liquids with an alkyl(carboxymethyl)dimethylammonium cation and a bis(2-ethylhexyl)phosphate anion of formula 1, where R is a methyl to decyl substituent. 2. A method for obtaining new adjuvants in the form of ionic liquids with an alkyl(carboxymethyl)dimethylammonium cation as defined in claim 1, characterized in that the alkyl(carboxymethyl)dimethylammonium chloride is dissolved in methanol or ethanol and exchanged with bis(2-ethylhexyl)phosphate sodium chloride to sodium salt molar ratio 1:1, at a temperature of 20 to 35°C, preferably 25°C, then the inorganic by-product is filtered off, then the product is dissolved in acetone to remove residual inorganic salt, the precipitate is filtered the solvent is evaporated from the product and dried at 70°C. 3. The use of new ionic liquids with an alkyl(carboxymethyl)dimethylammonium cation as defined in claim 1, as means of degreasing working surfaces. 4. Use according to claim 3, characterized in that the new ionic liquids with the alkyl(carboxymethyl)dimethylammonium cation are used in the form of an aqueous solution with a concentration of at least 0.05%. 5. Use according to claim 3, characterized in that the new ionic liquids with the alkyl(carboxymethyl)dimethylammonium cation are used in the form of a water-alcoholic solution with a concentration of at least 0.05%.