Highly stable and alkaline cleaning solutions and soluble surfactant

Abstract

The present invention relates to new alkaline, preferably highly alkaline, cleaning solutions comprising surfactants with improved stability and cleaning performance under such conditions. It further relates to novel surfactants.

Claims

1. A cleaning solution, comprising: a) one or more surfactant(s) according to Formula (I) ##STR00002## wherein: R.sub.1 is a linear, branched, or cyclic, saturated or unsaturated aliphatic group having from 3 to 7 carbon atoms, or an aryl group having 6 or 7 carbon atoms or an alkylaryl group having 7 carbon atoms; R.sub.2 and R.sub.3 may be identical or different and are bivalent alkyl radicals with two to four carbon atoms; R.sub.4, R.sub.5, and R.sub.6 may all be identical or two of them may be identical or all may be different and are selected from the group consisting of: ethyl group, 1-methylmethane group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, and tert-butyl group; X.sub.1, X.sub.2 and X.sub.3 may all be identical or two of them may be identical or all may be different and are selected from the group consisting of: OH and O.sup.−Y.sup.+, wherein Y.sup.+ is a cation; wherein: m is 0 or 1, n is 0, 1, 2 or 3; and wherein: if m=0 and R.sub.1 comprises a tertiary carbon atom attached to the nitrogen atom, then n is 1, 2 or 3; if n=0 and m=0 or 1, then R.sub.1 is selected from the group consisting of: a linear saturated aliphatic group having from 3 to 5 carbon atoms; a linear unsaturated aliphatic group having from 3 to 7 carbon atoms; a cyclic, saturated or unsaturated aliphatic group having from 3 to 7 carbon atoms; an aryl group having from 3 to 7 carbon atoms; and an alkylaryl group having from 3 to 7 carbon atoms; b) one or more alkaline compound(s); and c) water.

2. The cleaning composition of claim 1, wherein the one or more alkaline compounds of paragraph b) are present in an amount such that the total alkalinity of the cleaning solution, expressed as Na.sub.2O content, is 5 wt % or higher.

3. The cleaning solution of claim 2, wherein, if n=0 and m=0 or 1, R.sub.1 is a linear aliphatic group having 3 or 4 carbon atoms.

4. The cleaning solution of claim 2, wherein, if n=0 and m=0 or 1, R.sub.1 is a linear unsaturated aliphatic group having from 3 to 6 carbon atoms.

5. The cleaning solution of claim 2, wherein, if n=0 and m=0 or 1, R.sub.1 is an aryl group or alkylaryl group having from 3 to 6 carbon atoms.

6. The cleaning solution of claim 2, wherein, if n=0 and m=0 or 1, R.sub.1 is a cyclic, saturated or unsaturated aliphatic group having from 3 to 6 carbon atoms.

7. The cleaning solution of claim 2, wherein component b) is selected from the group consisting of: a metal hydroxide; an alkaline silicate; an alkaline phosphate; an amine; a chelating agent selected from the group consisting of: phosphates, carboxylates, phosphonates and polyphosphates; and mixtures of these compounds.

8. The cleaning solution of claim 2, wherein the composition does not include a hydrotroping agent.

9. The cleaning solution of claim 1, wherein component b) comprises at least one alkaline compound in an amount such that the total alkalinity of the cleaning solution, expressed as Na.sub.2O content, is 10 to 40 wt %.

10. The cleaning solution of claim 9, wherein component b) comprises one or more alkaline compound(s) selected from the group consisting of a strong base having a pKb value at 25° C. and 1 atm of below 1, and an alkaline silicate, or mixtures thereof, wherein the content of all silicates in sum in the overall composition is below 15% by wt.

11. The cleaning solution of claim 10, wherein component b) wherein the alkaline compound is selected from the group consisting of: sodium hydroxide; potassium hydroxide; potassium silicate; sodium silicate; and mixtures.

12. The cleaning solution of claim 9, wherein if n=0 and m=0 or 1, R.sub.1 is selected from the group consisting of: a) a linear aliphatic group having 3 or 4 carbon atoms; and b) a linear unsaturated aliphatic group having from 3 to 6 carbon atoms.

13. The cleaning solution of claim 9, wherein if n=0 and m=0 or 1, R.sub.1 is selected from the group consisting of: a) a cyclic, saturated or unsaturated aliphatic group having from 3 to 6 carbon atoms; and b) an aryl group or an alkylaryl group having from 3 to 6 carbon atoms.

14. The cleaning solution of claim 9, wherein the composition does not a hydrotroping agent.

15. A surfactant according to Formula (I): ##STR00003## wherein: R.sub.1 is a linear, branched, or cyclic, saturated or unsaturated aliphatic group having from 3 to 7 carbon atoms, or an aryl group having 6 or 7 carbon atoms or an alkylaryl group having 7 carbon atoms; R.sub.2 and R.sub.3 may be identical or different and are bivalent alkyl radicals with two to four carbon atoms; R.sub.4, R.sub.5, and R.sub.6 may all be identical or two of them may be identical or all may be different and are selected from the group consisting of: an ethyl group, 1-methylmethane group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, and tert-butyl group; X.sub.1, X.sub.2 and X.sub.3 may all be identical or two of them may be identical or all may be different and are selected from the group consisting of: OH and O.sup.−Y.sup.+, wherein Y.sup.+ is a cation; m is 0 or 1, n is 0, 1, 2 or 3, wherein: m is 0 or 1, n is 0, 1, 2 or 3, and wherein if m=0 and R.sub.1 comprises a tertiary carbon atom attached to the nitrogen atom, then n is 1, 2 or 3; if n=0 and m=0 or 1, then R.sub.1 is selected from the group consisting of: a linear saturated aliphatic group having from 3 to 5 carbon atoms; a linear unsaturated aliphatic group having from 3 to 7 carbon atoms; a cyclic, saturated or unsaturated aliphatic group having from 3 to 7 carbon atoms; an aryl group having from 3 to 7 carbon atoms; and an alkylaryl group having from 3 to 7 carbon atoms; if n=1 and m=0, then either R.sub.3 is a bivalent alkyl with 3 or 4 carbon atoms or R.sub.1 is a linear or branched unsaturated aliphatic group having from 3 to 7 carbon atoms, a cyclic, saturated or unsaturated aliphatic group having from 3 to 7 carbon atoms, an aryl group having from 3 to 7 carbon atoms, or an alkylaryl group having from 3 to 7 carbon atoms.

16. The surfactant of claim 15, wherein, if n=0 and m=0 or 1, R.sub.1 is a linear aliphatic group having 3 or 4 carbon atoms.

17. The surfactant of claim 15, wherein, if n=0 and m=0 or 1, R.sub.1 is a linear unsaturated aliphatic group having from 3 to 6 carbon atoms.

18. The surfactant of claim 15, wherein, if n=0 and m=0 or 1, R.sub.1 is an aryl group or an alkylaryl group having from 3 to 6 carbon atoms.

19. The surfactant of claim 15, wherein, if n=0 and m=0 or 1, R.sub.1 is a cyclic, saturated or unsaturated aliphatic group having from 3 to 6 carbon atoms.

Description

(1) Determining the Foaming Properties of Surfactants

(2) Foaming results from surfactants occupying the air/solution interface to stabilize films of solution that encircle air under agitation. Surfactants may produce more or less foam and contribute to higher or lower stability of these foams. This characteristic of a surfactant may be shown by shaking a tube in a controlled, repeatable fashion (generally through the use of automation) and then measuring the volume of foam in the tube relative to the volume of both foam and solution. Numerous examples of variations on this method may be found in scientific literature, such as Amaral, das Neves, J., Oliveira, Â. Z., and Bahia, M. F., “Foamability of Detergent Solutions Prepared with Different Types of Surfactants and Waters”, Journal of Surfactants and Detergents, 11, 275-278 (2008).

EXAMPLES

Example 1: Monosodium Cyclohexylamine Dipropionate

(3) Approximately 700 g of acrylic acid (obtained commercially from Sigma-Aldrich) was reacted with approximately 416 g of cyclohexylamine (obtained commercially from Sigma-Aldrich) for 6 hours under cooling with constant agitation at about 60-80° C. The resulting organic acid was neutralized in parts with aqueous sodium hydroxide over 2 hours under cooling with constant agitation at about 70° C. The neutralization was done to an extent that ensures that the partially neutralized acid is water soluble at room temperature. The reaction was performed in the presence of water such that the final water content was approximately 60 wt. %.

Example 2: Monosodium Butyloxypropylamine Dipropionate

(4) Approximately 470 g of acrylic acid (obtained commercially from Sigma-Aldrich) was reacted with approximately 390 g of butyloxypropylamine for 6 hours under cooling with constant agitation at about 60-80° C. The resulting organic acid was neutralized with aqueous sodium hydroxide in parts over 2 hours under cooling with constant agitation at about 70° C. The neutralization was done to an extent that ensures that the partially neutralized acid is water soluble at room temperature. The reaction was performed in the presence of water such that the final water content was approximately 50 wt. %.

Example 3: 1.5 Sodium Butyloxypropylaminopropylamine Tripropionate

(5) Approximately 232 g of acrylic acid (obtained commercially from Sigma-Aldrich) was reacted with approximately 192 g of n-butyloxypropylaminopropylamine for 6 hours under cooling with constant agitation at about 60-80° C. The resulting organic acid was neutralized in parts with aqueous sodium hydroxide over 2 hours under cooling with constant agitation at about 70° C. The neutralization was done to an extent that ensures that the partially neutralized acid is water soluble at room temperature. The reaction was performed in the presence of water such that the final water content was approximately 50 wt. %.

Example 4: Stability Exhibited by Monosodium Cyclohexylamine Dipropionate

(6) Approximately 4 g of a 40 wt. % monosodium cyclohexylamine dipropionate solution was added to 200 g of 20 wt. % sodium hydroxide (15.5% total alkalinity expressed as Na.sub.2O). This solution was heated to 150° C. and held at that temperature for 2 weeks. The aged sample was neutralized to a pH of 7 with hydrochloric acid and analyzed via liquid chromatography-mass spectorometry (LC-MS), using a Thermo Acclaim Surfactant Plus chromatography column. Mass spectrometric analyses were performed in positive electrospray ionization mode over the mass range of 100-2500 Daltons (Da) with a time of flight (TOF) mass spectrometer.

(7) The LC chromatograms for aged and un-aged amphoteric surfactant are shown in FIG. 1. The chromatographic peak at retention time 1.18 minutes was the same in both the aged and un-aged samples, and correlated to cyclohexylamine reacted with only one acrylic acid (m/z 172). For both samples, the mass spectra of the peak at retention time 1.7 minutes matched the expected [M+H]+ value of 244 for the structure of the surfactant.

(8) The relative concentrations of the components to the rest of the peaks show that the surfactant maintained its molecular integrity through the aging process.

Example 5: Stability Exhibited By Monosodium Butyloxypropylamine Dipropionate

(9) Approximately 4 g of a 40 wt. % monosodium butyloxypropylamine dipropionate solution was added to 200 g of 20 wt. % sodium hydroxide (15.5% total alkalinity expressed as Na.sub.2O). This solution was heated to 150° C. and held at that temperature for 2 weeks. The aged sample was neutralized to a pH of 7 with hydrochloric acid and analyzed via liquid chromatography-mass spectorometry (LC-MS), using a Thermo Acclaim Surfactant Plus chromatography column. Mass spectrometric analyses were performed in positive electrospray ionization mode over the mass range of 100-2500 Daltons (Da) with a time of flight (TOF) mass spectrometer.

(10) The LC chromatograms for aged and un-aged monosodium butyloxypropylamine dipropionate are shown in FIG. 2. The chromatographic peak at retention time 1.49 minutes was the same in both the aged and un-aged samples, and correlated to etheramine reacted with only one acrylic acid (m/z 204). The largest peak in both samples, at retention time 2.0 minutes matched the expected [M+H]+ for the structure of the expected product.

(11) The relative concentrations of the components to the rest of the peaks show that the surfactant maintained its molecular integrity through the aging process.

Example 6: Surface Tension Reduction and Critical Micelle Concentration for Monosodium Cyclohexylamine Dipropionate (Ex 1) and Monosodium Butyloxypropylamine Dipropionate (Ex 2)

(12) Monosodium Cyclohexylamine Dipropionate (Example 1) and Monosodium Butyloxypropylamine Dipropionate (Example 2) were examined to determine CMC in water and in 20% and 45% potassium hydroxide (KOH). These values and the equilibrium surface tensions (EST) at CMC are shown below in Table 1.

(13) TABLE-US-00001 TABLE 1 Surface Tension Reduction and Critical Micelle Concentration for Example Surfactants CMC (Wt %) EST (mN/m) 20% 45% 20% 45% Material Water KOH KOH Water KOH KOH Monosodium 9.0 0.05 0.03 39.7 40.8 40.9 Cyclohexylamine Dipropionate (Example 1) Monosodium 9.0 0.07 0.03 33.4 36.6 37.5 Butyloxypropylamine Dipropionate (Example 2)

(14) These values show that the claimed materials meet the definition of surfactants in that they will reduce surface tension and exhibit a critical micelle concentration.

Example 7: Foam Behavior for Example Surfactants

(15) The foaming properties of solutions of Monosodium Cyclohexylamine Dipropionate (Example 1), Monosodium Butyloxypropylamine Dipropionate (Example 2), and 1.5 Sodium Butyloxypropylaminopropylamine Tripropionate (Example 3), prepared as 2 wt % in 45% KOH, were examined. Samples of each solution were shaken vigorously in an automated apparatus to ensure identical treatment of each sample and the volume of foam relative to the total volume of solution and foam was determined. Results of this examination are shown below in Table 2.

(16) TABLE-US-00002 TABLE 2 Foaming Properties of Example Surfactants. Foam Volume (as Percentage of Solution and Foam Volume) Material Initial 1 Minute 3 Minutes Monosodium Cyclohexylamine 25.6 12.3 0.0 Dipropionate (Example 1) Monosodium Butyloxypropylamine 53.3 48.1 32.1 Dipropionate (Example 2) 1.5 Sodium 57.6 57.5 53.1 Butyloxypropylaminopropylamine Tripropionate (Example 3)

(17) It may be seen from this data that the claimed surfactants are capable of making both high and low foaming solutions.

Example 8: Dynamic Surface Tension of Monosodium Cyclohexylamine Dipropionate (Ex 1) and Monosodium Butyloxypropylamine Dipropionate (Ex 2)

(18) Solutions of Monosodium Cyclohexylamine Dipropionate (Example 1) and Monosodium Butyloxypropylamine Dipropionate (Example 2) were prepared at concentrations of 0.01 wt % and 0.005 wt % in 45% KOH. A bubble tensiometer was employed to demonstrate the migration speed of these surfactants in the alkaline solution, revealed by the lowering of the solutions surface tension as a function of surface age. Results of this testing are shown below in FIG. 3.