Formulations for enhanced oil recovery comprising sulfonates

Abstract

Compositions suitable for enhanced oil recovery comprising a) a mixture of α-sulfocarbonyl compounds of formulae (1) and (2) in a mixture ratio (1) to (2) of from 1:99 to 99:1 ##STR00001## wherein R.sub.1, R.sub.3 and R.sub.5, which may be the same or different at each occurrence, are hydrogen or a linear or branched alkyl chain having 1 to 20 carbon atoms, R.sub.2 and R.sub.4, which may be the same or different at each occurrence, may be a linear or branched alkyl group having 4 to 24 carbon atoms and in which the alkyl chain may comprise one or more cycloaliphatic groups, and X is H or a metal forming a salt with the sulfonate group, and b) a salt containing aqueous solution.

Claims

1. A composition suitable for enhanced oil recovery comprising a) a mixture of α-sulfocarbonyl compounds of formulae (1) and (2) in a mixture ratio (1) to (2) of from 1:99 to 99:1 ##STR00005## wherein R.sub.1, R.sub.3 and R.sub.5, which may be the same or different at each occurrence, are hydrogen or a linear or branched alkyl chain having 1 to 20 carbon atoms, R.sub.2 and R.sub.4, which may be the same or different at each occurrence, are a linear or branched alkyl group having 4 to 24 carbon atoms and in which the alkyl chain may comprise one or more cycloaliphatic groups, and X is H or a cation forming a salt with the sulfonate group, and b) a salt containing aqueous solution.

2. The composition in accordance with claim 1 comprising component a) in an amount of from 0.5 to 50 g/L.

3. The composition in accordance with claim 1 comprising component a) in an amount of from 1 to 25 g/L.

4. The composition in accordance with claim 1 wherein X is an ammonium cation or a metal cation selected from the group consisting of sodium, potassium, calcium and magnesium.

5. The composition in accordance with claim 1 wherein R.sub.1, R.sub.3 and R.sub.5, which may be the same or different, are hydrogen or an alkyl group with 1 to 6 carbon atoms.

6. The composition in accordance with claim 1 wherein R.sub.2 and R.sub.4, which may be the same or different, comprise 6 to 18 carbon atoms.

7. The composition in accordance with claim 1 wherein component a) is a mixture of 12-tricosanone monosulfonate and 12-tricosanondisulfonate.

8. The composition in accordance with claim 1 wherein component a) is a mixture of mono- and disulfonates of internal ketones obtained through ketonization of a coconut or palm kernel oil derived fatty acids cut.

9. The composition in accordance with claim 1 wherein component a) is a mixture of mono- and disulfonates of ketones obtained through ketonization of fatty acids selected from the group consisting of caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, naphthenic acids, isostearic acids, arachidic acid, behenic acid, lignoceric acid, cerotic acid, and mixtures thereof.

10. The composition in accordance with claim 1 wherein component a) is a mixture of mono- and disulfonates of ketones obtained through ketonization of fatty acids selected from the group consisting of 10-undecenoic acid, palmitoleic acid, oleic acid, linoleic acid, linolenic acid, erucic acid, and mixtures thereof.

11. The composition in accordance with claim 1 wherein mono- and disulfonates in component a) are present in a molar ratio of 5:95 to 95:5.

12. The composition in accordance with claim 1, further comprising an alkyl glyceryl ether sulfonate of general formula (3)
R.sub.6—O—[—CH.sub.2—CH(OH)—CH.sub.2—O—].sub.m—CH.sub.2CH(OH)—CH.sub.2—SO.sub.3Y  (3) or an alkoxylated alkyl glyceryl ether of formula 4
R.sup.6—O—[—CH.sub.2—CH(OH)—CH.sub.2—O—].sub.m—[—CH.sub.2—CH(CH.sub.3)—O—].sub.n—[—CH.sub.2—CH.sub.2—O].sub.p—CH.sub.2CH(OH)—CH.sub.2—SO.sub.3Y  (4) wherein R.sub.6 represents a linear or branched alkyl or alkenyl chain having of from 3 to 32 carbon atoms, m is 0 or an integer in the range of from 1 to 20, n and p are integers of from 0 to 20, and Y is a cation of the sulfonate group selected from the group consisting of sodium, potassium, ammonium, calcium and magnesium.

13. A composition comprising c) a mixture of α-sulfocarbonyl compounds of formulae (1) and (2) in a mixture ratio (1) to (2) of from 1:99 to 99:1 ##STR00006## wherein R.sub.1, R.sub.3 and R.sub.5, which may be the same or different at each occurrence, are hydrogen or a linear or branched alkyl chain having 1 to 20 carbon atoms, R.sub.2 and R.sub.4, which may be the same or different at each occurrence, are a linear or branched alkyl group having 4 to 24 carbon atoms and in which the alkyl chain may comprise one or more cycloaliphatic groups, and X is H or a cation forming a salt with the sulfonic acid group, and d) an alkyl glyceryl ether sulfonate of general formula (3) R.sub.6—O—[—CH.sub.2—CH(OH)—CH.sub.2—O—].sub.m—OCH.sub.2CH(OH)—CH.sub.2—SO.sub.3Y (3) or an alkoxylated alkyl glyceryl ether of formula (4) R.sub.6—O—[—CH.sub.2—CH(OH)—CH.sub.2—O—].sub.m—[CH.sub.2CH(CH.sub.3)—O].sub.n—[—CH.sub.2—CH.sub.2—O].sub.p—CH.sub.2CH(OH)—CH.sub.2—SO.sub.3Y (4) or a mixture thereof wherein R.sub.6 represents a linear or branched alkyl or alkenyl chain having of from 3 to 18 carbon atoms, m is 0 or an integer in the range of from 1 to 20, n and p are integers of from 0 to 20, and Y is a cation of the sulfonate group selected from the group consisting of sodium, potassium, ammonium, calcium and magnesium.

14. The composition in accordance with claim 12, wherein R.sub.6 represents a linear or branched alkyl or alkenyl chain having of from 5 to 18 carbon atoms.

15. The composition in accordance with claim 12, wherein m is an integer in the range of from 2 to 15.

16. The composition in accordance with claim 12, wherein n and p are integers of from 2 to 15 and n and p cannot be both equal to 0.

17. The composition in accordance with claim 13, wherein R.sub.6 represents a linear or branched alkyl or alkenyl chain having of from 5 to 18 carbon atoms.

18. The composition in accordance with claim 13, wherein m is an integer in the range of from 2 to 15.

19. The composition in accordance with claim 13, wherein n and p are integers of from 2 to 15 and n and p cannot be both equal to 0.

20. A process for enhanced oil recovery, the process comprising a first step of determining the salinity of the injection water and thereafter preparing a blend of internal ketone monosulfonates and disulfonates as defined in claim 1 having a mixing ratio of mono- and disulfonates providing the lowest interfacial tension with the crude oil for the given salinity, mixing the internal ketone sulfonate mixture with the injection water and optionally further ingredients and pumping the final composition into the reservoir to recover oil from the reservoir.

Description

EXAMPLES

Example 1—Synthesis of 12-Tricosanone

(1) Examples 1 and 2 show a preferred process for the manufacture of internal ketones which are the starting material for the internal ketone sulfonates used in the compositions of the present invention.

(2) The reaction was carried under argon in a round bottom flask equipped with mechanical stirring, Dean Stark apparatus and an addition funnel. In the reactor, 700 mg of iron powder were dispensed and 20 g of lauric acid was introduced into the addition funnel.

(3) A first partial amount of 5 g of acid was added into the reactor and the temperature was brought to 250° C. The mixture was stirred at this temperature for 30 minutes during which the color of the media changed to black and H.sub.2 gas was released.

(4) Then the temperature was raised to 300° C., the mixture was stirred during 1 h 30 and the remaining amount of lauric acid (15 grams) was slowly added into the reactor during 4 h 30 min at a flow rate which allowed keeping concentration of lauric acid in the reaction media very low (no accumulation of free acid in solution).

(5) At the end of the reaction, the addition funnel was replaced by a distillation apparatus and the products were distilled off at 290° C.-340° C. under 5 kPa pressure.

(6) Overall 4 cycles were carried out without any loss of performances reducing thereby the concentration of iron to less than 1 wt % relative to fatty acids amount converted.

(7) The conversion, selectivity and yield (measured by gas chromatography (GC) and isolated) are given in Table 1 below.

(8) TABLE-US-00001 TABLE 1 (all values in % of theory) Cycle no. Conversion Selectivity Raw yield Isolated yield 1 100 90 90 77 2 100 89 89 70 3 100 87 87 85 4 100 89 89 87

(9) The data show the superior selectivity and yield of the desired ketone.

Example 2—Cut of Coco Fatty Acids as Starting Material for the Synthesis of Internal Ketones

(10) Conversion of 400 g of coco fatty acids having the following weight distribution: C.sub.12: 55%, C.sub.14: 21%, C.sub.16:13%, C.sub.18: 12%.

(11) The transformation was carried out using 6.4 g of iron powder (1.6 wt %) and through 2 cycles involving a total of 200 g of fatty acids for each cycle.

(12) The reaction was carried under argon in a 1 l round bottom flask equipped with mechanical stirring, Dean-Stark apparatus and an addition funnel.

(13) Into the 250 mL addition funnel 200 g of coco fatty acids were introduced which were maintained in molten form by an external heater.

(14) 6.4 g of iron powder were dispensed into the reactor and a first portion of fatty acids (around 58 mL) were added into the reactor. The mixture was stirred (500 rpm) at 250° C. during 30 minutes in order to convert metallic iron to iron salts. During this period, the mixture color changed to black and hydrogen was released. Then the temperature was raised to 300° C.-320° C. to perform the transformation to fatty ketones. The mixture was stirred at this temperature during 1 h 30 and the remaining part of fatty acids was slowly added in the reactor during 5 hours at a flow which allowed keeping a low concentration of fatty acids in solution (no accumulation of free acids in solution). At the end of the reaction, the addition funnel was replaced by a distillation apparatus and the fatty ketones were recovered by distillation (290° C.-340° C., 5 kPa).

(15) A first crop of 141 g of fatty ketone was recovered as a white wax.

(16) The residue left in the reactor flask and mainly constituted of iron salts was used to convert the remaining 200 g of fatty acids in a second cycle. To achieve this, the distillation apparatus was replaced by the addition funnel containing 200 g of molten fatty acids and the operational steps described above were repeated.

(17) The total yield of the reaction after these 2 cycles was: 79% isolated as a white wax.

Example 3: Sulfonation of 12-Tricosanone (Obtained in Example 1) with 0.5 Moles of Sulfonating Agent Per Mol of Ketone

(18) The reactions were performed under a strictly anhydrous argon atmosphere. All the glassware was dried under vacuum at 110° C. overnight prior to the reaction. In a 100 mL round bottom flask equipped with a mechanical stirring, 10 g (29.5 mmol) of 12-tricosanone was dissolved in 27 mL of CHCl.sub.3 and the temperature of the mixture was set up at 45° C.

(19) In another round bottom flask, a solution of 1 mL of ClSO.sub.3H (14.5 mmol) dissolved in 5 mL of CHCl.sub.3 and 1.2 mL of dioxane (14.5 mmol) was carefully prepared. This solution was then slowly added to the ketone solution via cannula over 1 hour and through 4 crops in order to prevent disulfonation to occur in significant amounts. After addition, the mixture was allowed to stir at 60° C. during 1 hour and the solvent was removed under vacuum. Then the sulfonic acid was neutralized with 6.4 mL NaOH (10 wt %) along with an additional amount of 12 mL of water and under mechanical stirring at 60° C. during 1 hour in order to afford sodium sulfonate salts. The starting ketone in excess was finally separated from the monosulfonate after water evaporation, through filtration over silica (50 g) and elution with dichloromethane followed by CH.sub.2Cl.sub.2/MeOH (90:10). After evaporation of the solvent 4.1 g of white solid was obtained corresponding to 64% of isolated yield. As determined through NMR analysis, the product consisted of a mixture of 95 mol % monosulfonate and 5 mol % disulfonate.

Example 4—Sulfonation of 12-Tricosanone (Obtained in Example 1) with 1.5 Moles of Sulfonating Agent Per Mol of Ketone

(20) The reaction was performed as described above for Example 2 except that an excess of 1.5 eq (43.5 mmol) of ClSO.sub.3H (and 1.5 eq of dioxane) was reacted with 1 eq of 12-tricosanone (29.5 mmol). Quantities of solvent CHCl.sub.3 were also adjusted.

(21) Neutralization of sulfonic acids was carried out using 1.1 eq of NaOH (10 wt %) (calculated with respect to ClSO.sub.3H amounts) in water at 60° C. during 1 hour.

(22) No further purification was needed as under those conditions all the starting ketone was consumed. After neutralization, the obtained mixture of sulfonated salts (35 wt % active matter in water) could be used as such for the preparation of the compositions of the present invention.

(23) After evaporation of the water, 15 g of white solid is obtained corresponding to a quantitative isolated yield.

(24) As determined through NMR analysis, the product consisted of a mixture of 52 mol % monosulfonate and 48 mol % disulfonate.

Example 5—Sulfonation of Ketones Obtained in Example 2 with 0.5 Moles of Sulfonating Agent Per Mol of Ketone

(25) The reactions were performed under a strictly anhydrous argon atmosphere. All the glassware was dried under vacuum at 110° C. overnight prior to the reaction. In a 250 mL round bottom flask equipped with a mechanical stirring, 40 g (106.5 mmol) of internal ketones obtained in accordance with Example 2 was dissolved in 107 mL of CHCl.sub.3 and the temperature of the mixture was set up at 45° C.

(26) In another 50 mL round bottom flask, a solution of 3.8 mL of ClSO.sub.3H (56.5 mmol) dissolved in 17 mL of CHCl.sub.3 and 4.8 mL of dioxane (56.5 mmol) was carefully prepared. This solution was then slowly added to the ketone solution via cannula over 1 hour and through 4 crops in order to prevent disulfonation to occur in significant amounts. After addition, the mixture was allowed to stir at 60° C. during 1 hour and the solvent was removed under vacuum. Then the sulfonic acid was neutralized with 37.4 mL aqueous NaOH (10 wt %) under mechanical stirring at 60° C. during 1 hour in order to afford sodium sulfonate salts. The starting ketone in excess was finally separated from the monosulfonate salt after water evaporation, through filtration over silica (250 g) and elution with dichloromethane followed by CH.sub.2Cl.sub.2/MeOH (90:10). After evaporation of the solvent 19.4 g of white solid was obtained corresponding to 57% of isolated yield. As determined through NMR analysis, the product consisted of a mixture of 96 mol % monosulfonate and 4 mol % disulfonate.

Example 6—Sulfonation of Ketones Obtained in Example 2 with 1.5 Moles of Sulfonating Agent Per Mol of Ketone

(27) The reaction was performed as described above in Example 5 except that an excess of 1.5 eq (79.8 mmol) of ClSO.sub.3H (and 1.5 eq of dioxane) was reacted with 1 eq of internal C.sub.23-C.sub.35 fatty ketones (53.2 mmol). Quantities of solvent CHCl.sub.3 were also adjusted.

(28) Neutralization of sulfonic acids was carried out using 1.1 eq of NaOH (10 wt %) (calculated with respect to ClSO.sub.3H amounts) in water at 60° C. during 1 hour.

(29) No further purification was needed as under those conditions all the starting ketone was consumed. After neutralization the obtained mixture of sulfonated salts (35 wt % active matter in water) could be used as such for the preparation of the compositions of the present invention.

(30) After evaporation of the water, 28.1 g of white solid was obtained corresponding to a quantitative isolated yield. As determined through NMR analysis, the product consisted of a mixture of 61 mol % monosulfonate and 39 mol % disulfonate.

Example 7—Sulfonation of Ketones Obtained in Example 2 with 2.1 Moles of Sulfonating Agent Per Mol of Ketone

(31) The reaction was performed as described above in Example 5 except that an excess of 2.1 eq (111.7 mmol) of ClSO.sub.3H (and 2.1 eq of dioxane) was reacted with 1 eq of internal C.sub.23-C.sub.35 fatty ketones (53.2 mmol). Quantities of solvent CHCl.sub.3 were also adjusted.

(32) Neutralization of sulfonic acids was carried out using 1.1 eq of NaOH (10 wt %) (calculated with respect to ClSO.sub.3H amounts) in water at 60° C. during 1 hour. No further purification was needed as under those conditions all the starting ketone was consumed. After neutralization the obtained mixture of sulfonated salts (35 wt % active matter in water) could be used as such for the preparation of the compositions of the present invention.

(33) After evaporation of the water, 31.5 g of white solid was obtained corresponding to a quantitative isolated yield. As determined through NMR analysis, the product consisted of a mixture of 18 mol % monosulfonate and 82 mol % disulfonate

Example 8—Compositions of the Present Invention Comprising (Di)Sulfonated Compounds Derived from C.SUB.23.-C.SUB.35 .Internal Ketones Cut

(34) The performance of surfactant formulations comprising internal ketone (di)sulfonate obtained from a cut of coconut fatty acids (C.sub.12-C.sub.18) with different mono to disulfonate ratio at a temperature of 60° C. was determined in two different aqueous salt solutions (brines). The two brine compositions which have been investigated are described in Table 2.

(35) TABLE-US-00002 TABLE 2 Brine compositions NaCl (% by weight of CaCl2 (% by weight of total salt) total salts) Brine 1 100 0 Brine 2 83.9 16.1

(36) The internal ketone sulfonates were used in combination with an alkoxylated alkyl glyceryl ether of the following formula:

(37) ##STR00003##

(38) wherein n is 7 and m is 6.

(39) The ketone sulfonates and the AAGES were used in a concentration of 4 g/L each.

(40) Tables 3 and 4 show the solubility of the surfactant mixture in the two brines, the optimal salinity S* in the presence of dodecane as well as the approximate interfacial tension with dodecane. The optimal salinity S* corresponds to the salinity at which the interfacial tension with the oil reaches its minimum value. All experiments were performed at 60° C.

(41) TABLE-US-00003 TABLE 3 Performances of the surfactant formulations in Brine 1 Formulation Mono/Disulfonate solubility Ratio (g/l NaCl) S* (g/l NaCl) IFT (mN/m) 96/4%  Very low No three  >10.sup.−1- phase behavior (WIII) 46/54% 75 50 <10.sup.−2  1/99% >90 >90 Not measured

(42) TABLE-US-00004 TABLE 4 Performances of the surfactant formulations in Brine 2 Formulation Mono/Disulfonate solubility Ratio (g/L TDS) S* (g/l TDS) IFT (mN/m) 96/4%  Not soluble — — 46/54%  40 12 <10.sup.−2 40/60%* 45 26 <10.sup.−2 30/70%* >62 53 <10.sup.−2 S* represents the optimal salinity, IFT the interfacial tension and formulation solubility is the maximal salts concentration of the respective brine at which the surfactant mixture is soluble. *These ratios were obtained by blending the products 61/39 and 18/82

(43) These results show that internal ketone sulfonate surfactants can be used to obtain optimal performances (solubility and IFT) in various brine conditions. Such mixtures can thus be very useful to match different reservoir conditions.

(44) The optimal salinity S* in brine 2 (TDS g/l) can be easily modified and tuned by the ratio monosulfonate/disuflonate used. This ratio can be obtained directly in the synthesis by using the appropriate sulfonating agent:ketone ratio.

Example 9—Synthesis of C.SUB.15.-C.SUB.35 .Ketones Cut Starting from a C.SUB.8.-C.SUB.18 .Coco Saturated Fatty Acids Cut

(45) The reaction was carried under argon in a 750 mL reactor equipped with mechanical stirring, Dean Stark apparatus and an addition funnel.

(46) In the reactor, 6.8 g (0.12 mol) of iron powder were dispensed and 200 g (0.97 mol) of the coco saturated fatty acids cut (with the following distribution: C.sub.8: 7 wt %, C.sub.10: 8 wt %, C.sub.12: 48 wt %, C.sub.14: 17 wt %, C.sub.16: 10 wt %, C.sub.18: 10 wt %) was introduced into the addition funnel.

(47) A first partial amount of 50 g of fatty acids was added into the reactor and the temperature was brought to 250° C. The mixture was stirred at this temperature during 4 h 00. During this time the color of the media changed to black and H.sub.2 gas was released. FTIR analysis of the crude mixture shows complete formation of intermediate iron carboxylate complexes.

(48) The temperature was then raised to 330° C. and the mixture was stirred at this temperature during 2 h 00. During this time the intermediate iron carboxylate complexes are decomposed to fatty ketones, iron oxide and CO.sub.2. The remaining fatty acids (150 g) are slowly introduced into the reactor such that the temperature of the reaction medium doesn't fall down below 320° C. and at a flow rate which allowed keeping concentration of fatty acids in the reaction media very low (for example with an addition flow rate of around 25 g fatty acids/hour).

(49) Practically this can be done through the successive slow additions (1 hour per addition) of 3 portions of 50 g of melted fatty acids with 1 hour of stirring at 330° C. between each addition.

(50) At the end of the last addition, the crude medium is stirred at 330° C. during 2 hours and the reaction progress is monitored through FTIR. When the reaction is completed (no more iron complex detected by FTIR), the mixture is allowed to cool down at room temperature and 400 mL of CHCl.sub.3 is added to the crude media. The mixture is stirred at 40° C. in order to solubilize the product. The obtained suspension is filtered on a silica plug (400 g) and eluted using 3 L of chloroform. Evaporation of the solvent affords 161 g (0.46 mol) of the product C.sub.15-C.sub.35 ketones as a white wax (95% isolated yield) analytically pure.

Example 10—Sulfonation of the C.SUB.15.-C.SUB.35 .Ketones Cut Obtained Previously with 1.35 Moles of Sulfonating Agent Per Mol of Ketone

(51) The reactions were performed under a strictly anhydrous argon atmosphere. All the glassware was dried under vacuum at 110° C. overnight prior to the reaction. In a 500 mL round bottom flask equipped with a magnetic stirring, 40 g (113 mmol) of ketones C.sub.15-C.sub.35 was dissolved in 107 mL of CHCl.sub.3 and the temperature of the mixture was set up at 45° C.

(52) In another 100 mL round bottom flask, a solution of 10 mL of ClSO.sub.3H (153 mmol) dissolved in 44.5 mL of CHCl.sub.3 and 13.1 mL of dioxane (153 mmol) was carefully prepared. This solution was then slowly added to the ketone solution via cannula over 3.5 hours and through 5 crops. After addition, the solvent was removed under vacuum. Then the obtained sulfonic acid was neutralized with 67 mL NaOH (10 wt %) along with an additional amount of 30 mL of water and under mechanical stirring at 60° C. during 1 hour in order to afford sodium sulfonate salts. After neutralization, the obtained mixture of sulfonated salts (around 38 wt % active matter in water) could be used as such for the preparation of the compositions of the present invention. Evaporation of water affords 56.5 g of yellow solid corresponding to a quantitative yield. As determined through NMR analysis, the product consisted of a mixture of 62 mol % monosulfonate and 38 mol % disulfonate.

Example 11—Sulfonation of the C.SUB.15.-C.SUB.35 .Ketones Cut Obtained Previously with 1.5 Moles of Sulfonating Agent Per Mol of Ketone

(53) The reactions were performed under a strictly anhydrous argon atmosphere. All the glassware was dried under vacuum at 110° C. overnight prior to the reaction. In a 250 mL round bottom flask equipped with a magnetic stirring, 10 g (29 mmol) of ketones C.sub.15-C.sub.35 was dissolved in 27 mL of CHCl.sub.3 and the temperature of the mixture was set up at 45° C.

(54) In another 100 mL round bottom flask, a solution of 2.9 mL of ClSO.sub.3H (44 mmol) dissolved in 13 mL of CHCl.sub.3 and 3.8 mL of dioxane (44 mmol) was carefully prepared. This solution was then slowly added to the ketone solution via cannula over 2 hours and through 4 crops. After addition, the mixture is allowed to stir at 45° C. during 2 hours and the solvent was removed under vacuum. Then the obtained sulfonic acid was neutralized with 20.5 mL NaOH (10 wt %) along with an additional amount of 7 mL of water and under mechanical stirring at 60° C. during 1 hour in order to afford sodium sulfonate salts. After neutralization, the obtained mixture of sulfonated salts (around 38 wt % active matter in water) could be used as such for the preparation of the compositions of the present invention. Evaporation of water affords 15.4 g of yellow solid corresponding to a quantitative yield. As determined through NMR analysis, the product consisted of a mixture of 47 mol % monosulfonate and 53 mol % disulfonate.

Example 12—Sulfonation of the C.SUB.15.-C.SUB.35 .Ketones Cut Obtained Previously with 1.7 Moles of Sulfonating Agent Per Mol of Ketone

(55) The reactions were performed under a strictly anhydrous argon atmosphere. All the glassware was dried under vacuum at 110° C. overnight prior to the reaction. In a 250 mL round bottom flask equipped with a magnetic stirring, 20 g (58 mmol) of ketones C.sub.15-C.sub.35 was dissolved in 54 mL of CHCl.sub.3 and the temperature of the mixture was set up at 45° C.

(56) In another 100 mL round bottom flask, a solution of 6.6 mL of ClSO.sub.3H (99 mmol) dissolved in 30 mL of CHCl.sub.3 and 8.4 mL of dioxane (44 mmol) was carefully prepared. This solution was then slowly added to the ketone solution via cannula over 2.5 hours and through 5 crops. After addition, the mixture is allowed to stir at 45° C. during 2 hours and the solvent was removed under vacuum. Then the obtained sulfonic acid was neutralized with 44 mL NaOH (10 wt %) along with an additional amount of 10 mL of water and under mechanical stirring at 60° C. during 1 hour in order to afford sodium sulfonate salts. After neutralization, the obtained mixture of sulfonated salts (around 38 wt % active matter in water) could be used as such for the preparation of the compositions of the present invention. Evaporation of water affords 31.3 g of yellow solid corresponding to a quantitative yield. As determined through NMR analysis, the product consisted of a mixture of 30 mol % monosulfonate and 70 mol % disulfonate.

Example 13—Compositions of the Present Invention Comprising (Di)Sulfonated Compounds Derived from C.SUB.15.-C.SUB.35 .Internal Ketones Cut

(57) The performance of surfactant formulations comprising internal ketone (di)sulfonate obtained from a cut of coconut fatty acids (C.sub.8-C.sub.18) with different mono to disulfonate ratio at a temperature of 60° C. was determined in two different aqueous salt solutions (brines). The two brine compositions which have been investigated are described in Table 5.

(58) TABLE-US-00005 TABLE 5 Brine compositions NaCl (% by weight CaCl2 (% by weight of total salt) of total salts) Brine 1 100 0 Brine 2 83.9 16.1

(59) The internal ketone sulfonates were used in combination with an alkoxylated alkyl glyceryl ether of the following formula:

(60) ##STR00004##
wherein n is 7 and m is 6.

(61) The ketone sulfonates and the AAGES were used in a concentration of 4 g/L each.

(62) Tables 6 and 7 show the solubility of the surfactant mixture in the two brines, the optimal salinity S* in the presence of dodecane as well as the approximate interfacial tension with dodecane. The optimal salinity S* corresponds to the salinity at which the interfacial tension with the oil reaches its minimum value. All experiments were performed at 60° C.

(63) TABLE-US-00006 TABLE 6 Performances of the surfactant formulations in Brine 1 Mono/ Formulation Disulfonate solubility S* IFT (%) (g/I NaCl) (g/I NaCl) (mN/m) 30/70% 80 145  5.8 .Math. 10.sup.−3 47/53% 115 100 1.07 .Math. 10.sup.−3 50/50% * >84 81  0.5 .Math. 10.sup.−3 62/38% 70 50 0.34 .Math. 10.sup.−3 *: These ratios were obtained by blending the products with 62% and 47%