Highly-concentrated flowable salts of alkyl polyalkoxy sulphates

Abstract

The present invention is directed to highly-concentrated compositions of salts of alkyl polyalkoxy sulphates, whereby in total at least ⅔ of all alkoxy unit of the alkyl polyalkoxy sulphates are propoxy units.

Claims

1. Highly-concentrated alkyl polyalkoxy sulphate composition, comprising: a) more than 80% by weight salts of alkyl polyalkoxy sulphates, whereby the alkyl polyalkoxy sulphates have in average 3 to 20 alkoxy groups, at least ⅔ of all alkoxy groups of the alkyl polyalkoxy sulphates are propoxy groups and the alkyl residue is a fatty alcohol residue with 13 to 18 carbon atoms or is a mixture of C12 and C13 fatty alcohol residues and b) 5 to below 20% by weight water; said compositions being flowable at least at 25° C., wherein flowable means having a viscosity of below 10000 mPas measured in accordance with DIN 53019 at 25° C. and with a shear rate of D=10 s.sup.−1.

2. Composition in accordance with claim 1, whereby the fatty alcohol residue has 13 to 17 carbon atoms.

3. The composition of claim 2, wherein the fatty alcohol residue has 13 to 15 carbon atoms.

4. Composition in accordance with claim 1, wherein the fatty alcohol residue is present in the form of a mixture containing branched fatty alcohol residues.

5. The composition in accordance with claim 4, wherein the fatty alcohol residue contains more than 40 mol % branched fatty alcohol residues.

6. Composition is accordance with claim 4, wherein more than 50% of the branches are on the C2 carbon atom.

7. Composition in accordance with claim 1, wherein the alkoxy groups of the alkyl polyalkoxy sulphate salts are exclusively propoxy groups.

8. The composition of claim 7 wherein the alkoxy groups are 3 to 13 propoxy groups on average.

9. The composition of claim 8, wherein the alkoxy groups are 4 to 10 propoxy groups on average.

10. Composition in accordance with claim 1, wherein the proportion of the salts of the alkyl polyalkoxy sulphates is greater than 80 to 95% by weight.

11. Composition in accordance with claim 1, wherein the concentration of water is 5 to 18% by weight.

12. Composition in accordance with claim 1, wherein the salts are selected from the group consisting of sodium salts, potassium salts, and mixtures thereof.

13. Composition in accordance with claim 1 having a pour point of less than −5° C.

14. The composition of claim 13 wherein the pour point is below −15° C.

15. Composition in accordance with claim 1 further comprising 0.05 to 5% by weight of a buffer.

16. The composition of claim 15 comprising 0.1 to 2% by weight buffers.

17. Composition in accordance with claim 1 containing 0 to 10% by weight of a non-ionic substance in accordance with DIN EN 13273:2001.

18. The composition of claim 17, wherein the non-ionic substances are present in an amount of up to 5% by weight.

19. Composition in accordance with claim 1 containing less than 8 weight % other ionic substances.

20. The composition of claim 19 wherein the other ionic substances are present in an amount of up to 4% by weight.

21. Composition in accordance with claim 1 comprising less than 5 weight % other compounds.

22. Method of producing the composition in accordance with claim 1 comprising at least the following steps: reacting in a falling film reactor an alkoxylated fatty alcohol with SO.sub.3, wherein the alkoxylated fatty alcohol has in average 3 to 20 alkoxy groups, at least ⅔ of all alkoxy groups of the alkyl polyalkoxy sulphates are propoxy groups and the alkyl residue is a fatty alcohol residue with 13 to 18 carbon atoms or is a mixture of C12 and C13 fatty alcohol residues, performing a gas/liquid-phase separation and neutralizing the liquid phase with an alkali hydroxide in aqueous solution comprising more than 25 weight % alkali hydroxide.

23. Method in accordance with claim 22, whereby the reaction takes place with SO.sub.3 at 20 to 60° C.

24. The method of claim 23, wherein the reaction takes place at 25 to 40° C.

25. Method in accordance with claim 22, whereby the neutralization takes place at 30 to 70° C., and with aqueous alkali hydroxides containing less than 55% by weight alkali hydroxide.

26. The method of claim 25 wherein the neutralization takes place at 50 to 60° C.

27. The method of claim 25, wherein the alkali hydroxides are selected from the group consisting of sodium hydroxide and potassium hydroxide, and mixtures thereof.

28. Method in accordance with claim 22, whereby on completion of the neutralization the pH of the neutralized liquid phase is greater than 10.

29. The method of claim 28, wherein the pH is 11 or greater.

30. Method in accordance with claim 22, wherein an SO.sub.3/air mixture with 3 to 10% by weight SO.sub.3 is used.

31. Method in accordance with claim 22, wherein the alkoxylated fatty alcohol has exclusively propoxy groups.

32. The method of claim 31, wherein the alkoxylated fatty alcohol has 3 to 13 propoxy groups on average.

33. The method of claim 32, wherein the alkoxylated fatty alcohol has 4 to 10 propoxy groups on average.

34. Method of facilitating crude oil extraction from a downhole formation, comprising: diluting the composition of claim 1 with water to a desired concentration; injecting the composition into the formation to form a microemulsion and facilitate recovery.

35. The method of claim 34, wherein the composition is injected into the formation for tertiary oil recovery.

36. Highly-concentrated alkyl polyalkoxy sulphate composition, comprising: a) more than 80% by weight salts of alkyl polyalkoxy sulphates, whereby the alkyl polyalkoxy sulphates have in average 3 to 20 alkoxy groups, at least ⅔ of all alkoxy groups of the alkyl polyalkoxy sulphates are propoxy groups and the alkyl residue is a fatty alcohol residue with 14 to 18 carbon atoms and b) 5 to below 20% by weight water; said compositions being flowable at least at 25° C., wherein flowable means having a viscosity of below 10000 mPas measured in accordance with DIN 53019 at 25° C. and with a shear rate of D=10 s.sup.−1.

37. Highly-concentrated alkyl polyalkoxy sulphate composition, comprising: a) more than 80% by weight salts of alkyl polyalkoxy sulphates, whereby the alkyl polyalkoxy sulphates have in average 3 to 20 alkoxy groups, at least ⅔ of all alkoxy groups of the alkyl polyalkoxy sulphates are propoxy groups and the alkyl residue is a linear fatty alcohol residue with 12 to 18 carbon atoms or a mixture of linear and branched fatty alcohol residues with 12 to 18 carbon atoms and b) 5 to below 20% by weight water; said compositions being flowable at least at 25° C., wherein flowable means having a viscosity of below 10000 mPas measured in accordance with DIN 53019 at 25° C. and with a shear rate of D=10 s.sup.−1.

38. The composition of claim 37, wherein the alkyl residue is a linear fatty alcohol residue with 12 to 18 carbon atoms.

Description

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(1) Preferred forms of embodiment form the subject matter of the sub-claims or are described below.

(2) Suitable for use as fatty alcohols or fatty alcohol residues are linear or branched primary alcohols with 8 to 18 carbon atoms, preferably with 12 to 17, more particularly with 12 to 15 carbon atoms, and preferably more particularly mixtures containing at least more than 25 mol % branched primary alcohols.

(3) Particularly suitable are the above fatty alcohols or alcohol residues with more than 40 mol % branched portions and very particularly fatty alcohols with on average at least one branch per molecule, more particularly (greater than 50%) on the C2, C3 or C4 carbon atom, more particularly on the C2 carbon atom. The branching preferably has 1, 2, 3 and/or 4 carbon atoms.

(4) The alkoxylation takes place with an average of 3 to 20 alkoxy groups, preferably 3 to 16 in accordance with the methods known to a person skilled in the art, whereby the alkoxylates can exhibit a conventional or a narrow homolog distribution. Contents of ethylene oxide groups or higher alkylene oxide such as butylene oxide groups are possible, if at least ⅔ of all alkoxy groups are propylene oxide. Particularly preferably the alkoxylate exclusively has 3 to 13, more particularly 4 to 10, propoxy groups.

(5) The sulphation of the alcohol propoxylates can take place a in known manner for fatty alcohol ether sulphates with the usual methods, whereby the use of falling film reactors is preferred. As sulphation agents oleum, chlorosulphonic acid, amidosulphonic acid (sulfamic acid) or more particularly sulphur trioxide, for example, can be considered, whereby the latter is used diluted with an inert gas. The resulting sulphuric acid semi-ester is not stable and must therefore immediately be transferred into a neutralisation cycle in which it is converted, under high shear, with as highly concentrated aqueous alkali hydroxide as possible, more particularly 50% sodium hydroxide solution. In the preferred forms of embodiment the temperature during neutralisation is kept at 45 to 65° C., more particularly 50 to 60° C., at a pH value (related to 1% of the product in water) of pH 10 and higher, more particularly at least 11 and higher, in order to avoid viscosity peaks in the medium concentration ranges.

(6) The thus obtained highly-concentrated alcohol ether sulphate (salt) contains smaller portions of alcohols, propylene glycols (also sulphated) and alcohol propoxylates. The proportion of unsulphated material in the end product is typically 0 to 10% by weight, preferably 0 to less than 5% by weight. The content of alkyl polyalkoxy sulphate salts in accordance with the invention in the compositions is more than 75% by weight, more particularly more than 80% by weight, preferably more than 82% by weight and more particularly up to 95% by weight.

(7) The obtained product can, but does not have to be mixed with commercially available preservatives and/or buffers in order to increase the stability to chemical decomposition and/or the stability to microorganisms in possibly diluted form. In a preferred form of embodiment 0.05 to 5% by weight, more particularly 0.1 to 2% by weight of citric acid is added to the product.

(8) The compounds are used as an oil-soluble lubricant, e.g. in metal working, but more particularly as a surface active substance (surfactant) for deployment in improved or tertiary crude oil recovery. Together with the entrapped crude oil, the aqueous surfactant solution, which can also contain other components such as polymers, solvents, co-surfactants, salts, alkalisation agents, preserving agents, forms a micro-emulsion which is characterised by an extremely low interfacial tension and can thereby solubilise and mobilise the oil.

(9) The flowability of a liquid phase depends on many external factors such as the temperature, the container, the pump and the viscosity. In connection with the invention flowable means that at a temperature of 25° C. and a shear rate of D=10 s.sup.−1 the compound has a viscosity of less than 10000 mPas, preferably even less than 5000 mPas. The viscosity can be determined with the aid of commercially available measuring devices such as rotational viscometers or rheometers with cone/plate measuring geometry in accordance with DIN 53019.

(10) The oil solubility of the compound in accordance with the invention is preferably at least 5% by weight in paraffin oil (e.g. Merkur® WOP 100 PB) or mineral oil (e.g. Shell Gravex® 915), whereby at 25° C. gentle stirring results in a clear solution.

(11) To determine the dilutability, at room temperature (25° C.) the product is mixed with water at such a ratio that a 20% by weight solution (anionic active substance) is produced. If this can take place in a glass beaker through manual stirring with a spatula or glass rod without passing through highly viscous states which can no longer be stirred and therefore mixed by hand the product is by definition easily dilutable. If not, the product cannot be easily diluted in water.

(12) In connection with this invention the pour point means that (in accordance with ASTM D97-09) the product is cooled in 3° C. steps. If after 10 minutes at this temperature it does not flow within 5 seconds of tilting the container into the horizontal, the 3° C. higher value is taken as the pour point.

Example 1

(13) A branched primary C12/C13 alcohol (ISALCHEM® 123) with on average 8 propoxy groups was sulphated in a continuous sulphation apparatus.

(14) Raw material: ISALCHEM® 123+8 PO(OH number: 83.2 mg KOH/g, water: 0.03%, molecular weight: 674.3 g/mol). At a V.sub.2O.sub.5 catalyst gaseous SO.sub.2 was converted to SO.sub.3 at high temperature. The gas was cooled and diluted with air (dew point −60° C.). The proportion of SO.sub.3 in the air was 7% by volume.

(15) In a falling film reactor with distributors the propoxylated alcohol was made to react with the SO.sub.3/air mixture. The reaction gas flows though the falling film reactor at high speed and generates high turbulences on contact with the propoxylated alcohol. This resulted in an intensive exchange of substances. Intensive cooling of the falling film reactor ensures the removal of the reaction heat. Gas/liquid separation was carried out at the outlet of the falling film reactor. The fluid phase is taken for neutralisation, the gaseous phase for exhaust gas treatment.

(16) The product is pumped around in a neutralisation circuit with the appropriate neutralisation medium. A pH value regulator adds the appropriate quantity of alkaline components, in this case aqueous NaOH, 50% by weight. At the same time the product is homogenised in the circuit though a very highly shearing mixer tool. The finished product was removed continuously from the neutralisation circuit. 0.1% by weight citric acid was added to the finished product.

(17) The conversion parameters were as follows: Temperature in the converter: 450° C. SO.sub.3 concentration in the reaction gas: 7% by volume Molar ratio propoxylate/SO.sub.3: SO.sub.3 in excess Quantity used (propoxylate): 3.9 kg/hour hydroxyl number material used: 83.2 mg KOH/g Temperature at the lower outlet of the falling film reactor: 25-30° C. Theoretical acid number, sulphuric acid semi-ester: 74.4 mg KOH/g Actual acid number, sulphuric acid semi-ester 94 mg KOH/g Temperature neutralisation circuit: 55-60° C.

(18) A product with the following composition was obtained: Anionic active substance 90+/−1% by weight (DIN ISO 2271) Unsulphated material (non-ionic substance): <1% by weight % (DIN EN 13273) Na.sub.2SO.sub.4: 0.55% by weight Free alkali: 0.01% by weight Water: around 10% by weight
with the following properties: pH 1% in water: 9.3 Pour point: −24° C. 5% tel quel in paraffin oil: clearly soluble 5% t.q. in mineral oil: clearly soluble Viscosity (in mPas, at pH>11.25° C. and 10 s.sup.−1): 1100

Other Examples

(19) In an analogue manner to example 1 a branched primary C14/C15 alcohol (ISALCHEM® 145) with on average 8 propoxy groups, a partially branched primary C14/C15 alcohol (LIAL® 145) with on average 3.8 PO (propoxy) groups, a partially branched primary C14/C15 alcohol (LIAL® 145) with on average 9.8 PO groups, a partially branched primary C12/C13 alcohol (SAFOL® 23) with on average 6.5 PO groups, a partially branched primary C12/C13 alcohol (SAFOL® 23) with on average 12.5 PO groups, a partially branched primary C16/C17 alcohol (LIAL® 167) with on average 4 PO groups, a linear C12 alcohol with on average 12.8 PO groups and a linear C12/C14 alcohol with on average 4 PO groups were converted to the corresponding alcohol propoxy sulphate salts. The obtained compounds and properties are out in table 1 below.

Comparative Examples (Not in Accordance with the Invention)

(20) ISALCHEM™ 123+8PO SO.sub.3Na, anionic active 26.7% by weight, unsulfphated material 2.6% (calculated on 100% by weight active): not clearly soluble in mineral oil and paraffin oil, pour point −6° C.

(21) ISALCHEM™ 145+8PO SO.sub.3Na, anionic active 33.3% by weight, unsulphated material 9.4% (calculated on 100% by weight active): not clearly soluble in mineral oil and paraffin oil, pour point +3° C.

(22) MARLINAT™ 242/70 (C12C14+2EO SO.sub.3Na, anionic active 70% by weight): not clearly soluble in mineral oil and paraffin oil, not easily dilutable.

(23) SAFOL™ 23 2EO SO.sub.3Na, anionic active 70 wt. %: not clearly soluble in mineral oil and paraffin oil, not easily dilutable.

(24) ALFOL™ 1218 7EO (narrow range) SO.sub.3Na, high active (>75 wt. % anionic active matter): viscosity at 25° C./10 s.sup.−1>20000 mPas, not easily dilutable

(25) TABLE-US-00001 TABLE 1 ISALCHEM LIAL LIAL SAFOL SAFOL Linear Linear 145 + 8 145 + 3.8 145 + 9.8 23 + 6.5 23 + 12.5 C12 + 12.8 C12C14 + 4 PO SO.sub.3Na PO SO.sub.3Na PO SO.sub.3Na PO SO.sub.3Na PO SO.sub.3Na PO SO.sub.3Na PO SO.sub.3Na Anionic active substance, 89.2 89.3 83.0 89 83 89 80 a-WAS (% by weight) Unsulphated material 2.1 2 9 1 3 7 <1 (% by weight) Na.sub.2SO.sub.4 (% by weight) 0.6 0.4 0.6 0.3 0.3 0.5 0.3 Free alkali (% by weight) 0.04 0.04 0.7 0.1 0.1 0.1 1.6 Water (% by weight) 8.1 10.6 8 8 6 6 17 pH 1% in water 9.5 9.5 11.1 10.1 9.9 9.1 11.6 Pour point (° C.) −21 −18 −21 <−24 <−24 <−24 n.d. 5% t.q. in mineral oil Clear Clear Clear Clear Clear Clear Clear Viscosity (mPas, at pH >11, 1300 1600 1200 1000 1200 1050 9000 25° C. and 10 s.sup.−1) Easily dilutable Yes Yes Yes Yes Yes Yes Yes