JP2006008517A - Branched surfactant containing fluoroalkyl group and hydrocarbon group - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a surfactant useful in a carbon dioxide-water system. <P>SOLUTION: The surfactant is represented by general formula (I) [Rf is a (per)fluoroalkyl group, a (per)fluoroether group or a (per)fluoropolyether group; Rh is an alkyl group; Y is O, S or NR (R is a hydrogen atom, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or t-butyl); p and q are not 0 at the same time and are each 0 or 1; M is a hydrogen atom, an alkali metal, 1/2 an alkaline earth metal or ammonium]. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a branched surfactant having a fluoroalkyl group and a hydrocarbon group.

Background art and problems

  With the emergence of environmental problems, a technology that uses CO2 as a solvent instead of highly toxic organic solvents has attracted attention. In addition, if the compound can be handled in CO2, there is a possibility that the wastewater treatment cost can be greatly reduced, and its application to industrial fields with high wastewater treatment costs such as dyeing, plating, organic synthesis, extraction, etc. is attracting particular attention. .

  For such applications, a surfactant for mixing carbon dioxide and an aqueous solvent is required.

As a hybrid type fluorine-based compound, H (CF ₂ CF ₂ ) _n (CH ₂ CH ₂ O) _n OOCCH (OSO ₃ Na) CH ₂ COOR is disclosed in Patent Document 1 as an additive for improving the physical properties of photosensitive materials. H (CF ₂ CF ₂ ) _n CH ₂ OCH ₂ CH (OSO ₃ Na) R is described in Patent Document 2 as an additive for improving the coating properties of photosensitive materials, and H (CF ₂ CF ₂ ) _n CH ₂ OCH ₂ CH (OSO ₃ Na) CH ₂ OR is described in Patent Document 3 as an antistatic material for a photosensitive material.

On the other hand, surfactants that exhibit high functions in carbon dioxide are very limited, and sulfosuccinates having fluorine groups are reported in Non-Patent Documents 1 to 3, and are double-stranded or branched. There is a need for a hydrophobic group of structure. It was also known that the hybrid type has a higher function even in a branched structure. For example, Non-Patent Document 4 reported that C ₇ F ₁₅ CH (OSO ₃ Na) C ₇ H ₁₅ has a high function of taking water into carbon dioxide. However, this compound was not practical because of its low stability. Further, as a result of further trials by the present inventors, it was confirmed that the function of taking in water was insufficient.

  For this reason, synthesis of stable and highly functional hybrid surfactants has recently been reported (Non-Patent Documents 5 to 8). However, these known hybrid surfactants do not exhibit a sufficient function in carbon dioxide (Non-patent Document 3).

The phosphate ester reported in Non-Patent Document 9 expresses a high function in carbon dioxide, but the phosphate ester may be hydrolyzed and has a problem in stability during long-term use. In addition, it was confirmed that the phosphate ester was insufficient in function by a further test by the present inventors.
Japanese Patent Laid-Open No. 51-32222 Japanese Examined Patent Publication No. 52-26687 Japanese Examined Patent Publication No. 52-26687 Progr, Colloid Polym, Sci. 2000, 115, 214 Langmu1r 2001, 17, 274 Langmuir 2003, 19 pp. 220 Langmuir l994, 10, 3536 Langmuirl 995, 11, 466 Abstract of Oil Chemistry Discussion 2000, 305, 306 Summary of Oil Chemistry Conference 2002, 101 J. Am. Chem. SOC. 2002, 124, 6516 J. Am. Chem. SOC. 2002, 124, 1834

  It is an object of the present invention to provide a surfactant that can be used in a carbon dioxide-water system.

The present invention provides the following surfactants.
1. The following general formula (I)

(In the formula, Rf represents a (per) fluoroalkyl group, a (per) fluoroether group, or a (per) fluoropolyether group, and Rh represents an alkyl group.
Y is O, S or NR (R represents a hydrogen atom, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or t-butyl).
p and q are not 0 but 0 or 1 at the same time. )
M represents a hydrogen atom, an alkali metal, 1/2 alkaline earth metal or ammonium. )
A surfactant represented by
2. Item 2. The surfactant according to Item 1, wherein Rf has 5 to 12 carbon atoms.
3. General formula: RfCH ₂ OCH ₂ CH (OSO ₃ M) CH ₂ ORh
Item 3. The surfactant according to Item 1 or 2, wherein Rf, Rh, and M are as defined above.
4). Item 4. Use of the surfactant according to any one of Items 1 to 3 for improving the solubility of a polar substance in supercritical, subcritical, or liquid carbon dioxide.

Hereinafter, the present invention will be described in more detail.

The surfactant of the present invention can mix CO ₂ (supercritical, subcritical or liquid) with water or a polar compound, and is an organic / inorganic chemical reaction in a CO ₂ -water system or an electrochemical reaction such as plating. Furthermore, it is possible to improve the efficiency of extraction, washing, staining and the like. Moreover, CO ₂ - and has a much stability sufficiently withstand repeated use in an aqueous system.

  Such a surfactant is preferably a hybrid surfactant having a sulfate group and one fluoroalkyl group and one alkyl group.

In the surfactant of general formula (I):
Rf is a linear or branched alkyl group having one or more fluorine atoms, and may be a perfluoroalkyl group. Rf has 4 to 20, preferably 5 to 18, more preferably 5 to 12 carbon atoms. Preferred specific examples of Rf include the following:
As a (per) fluoroalkyl group:
_{C n F 2n + 1 (CH} 2) m - (n is an integer of 5 to 12, m is an integer of 0);
HC _n F _2n (CH ₂ ) _m — (n represents an integer of 5 to 12, m represents an integer of 0 to 10),
Examples of the (per) fluoroether group include Rf1-O—Rf2 such as C ₃ F ₇ OCF (CF ₃ ) — (Rf1 is a (per) fluoroalkyl group having a straight chain or branched chain of C _{1 to} C _6. Rf2 is a (per) fluoroalkylene group having a straight chain or branched chain of C _{1 to} C ₄ .

Examples of (per) fluoropolyether groups include Rf1- (O—Rf2) r (Rf1, Rf2 as defined above) such as C ₃ F ₇ OCF (CF ₃ ) CF ₂ OCF (CF ₃ ) —. R is an integer of 2 to 4)
Rh is a linear or branched alkyl group having 3 to 18, preferably 4 to 12, more preferably 4 to 10 carbon atoms. Preferable specific examples of Rh include (n-, sec-, iso-, tert-) butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl:
M is a hydrogen atom, alkali metal (Na, K, Li, Cs), 1/2 alkaline earth metal (Ca, Mg, Ba), or ammonium.

As a balance between the CO2 affinity part (Rf) and the hydrophilic group (Rh),
(Rf carbon number) / (Rh carbon number) = 1/2 to 2/1 is preferable, and 2/3 to 3/2 is more preferable.

  Specific examples of the surfactant of the present invention are shown below.

  The surfactant of the present invention is a commercial product or can be easily produced by those skilled in the art by a known method (for example, Patent Documents 1 to 3).

  The amount of the surfactant used in the present invention is desirably about 0.001 to 2000 wt%, preferably about 0.01 to 1000 wt%, more preferably about 0.1 to 500 wt% with respect to the aqueous solution.

Further CO ₂ - in water-based, it is also possible addition of an organic solvent (co-solvent) below. For example, alcohols such as methanol, ethanol, propanol, butanol and pentanol, ketones such as acetone, esters such as acetonitrile and ethyl acetate, ethers such as ethyl ether, chlorofluorocarbons, halides such as methylene chloride and chloroform In particular, those having low toxicity and low molecular weight are desirable.

  The CO2 used in the present invention is used in a liquid, subcritical, or supercritical state.

  According to the present invention, it is possible to provide a surfactant having a sufficiently high water uptake value and having a sufficient micelle forming ability in a mixed system of CO 2 / water and a polar compound (for example, inorganic salt, polar organic compound, etc.)

  EXAMPLES Hereinafter, although an Example and a reference example demonstrate this invention concretely, this invention is not limited only to this.

The compound structure, synthesis method, and spectral data are described below.
Example 1
C ₈ F ₁₇ CH ₂ CH (OSO ₃ Na) CH ₂ OC ₈ H ₁₇ 1
A mixture of heptadecafluoropropylene oxide (1.09 g, 2.3 mmol), octanol (1.02 g, 7.8 mmol) and 1 drop of sulfuric acid was heated with stirring at 100 ° C. for 48 hours. The mixture was extracted with ethyl acetate, and the organic layer was washed with saturated aqueous sodium hydrogen carbonate and brine, dehydrated with magnesium sulfate, and the solvent was evaporated under reduced pressure. The obtained reaction product was separated by silica gel column chromatography (n-hexane: EtOAc = 30: 1) to obtain an alcohol form (830 mg, 60%). SO3-Py complex (416 mg, 2.6 mmol) was added to the alcohol obtained here, and the mixture was stirred in 5 ml of pyridine at 40 ° C. for 24 hours. The reaction was opened in saturated sodium bicarbonate water and heated to dryness. The remaining reaction product was extracted with acetone using a Soxhlet extractor to remove inorganic salts (730 mg, 2 steps, 45%).
Colorless amorphous: ¹ H-NMR (CDCl ₃ ): δ0.88 (t, J = 6.5Hz, 3H), 1.15-1.47 (m, 10H), 1.47-1.65 (m, 2H), 2.47-2.87 (m, 2H), 3.35-3.62 (m, 2H), 3.62-3.78 (m, 2H), 4.74-4.90 (m, 1H).
IR (KBr, cm ^-1 ): 2934, 1243, 1213, 1152, 951.

Example 2
C ₆ F ₁₃ CH ₂ CH (OSO ₃ Na) CH ₂ OC ₆ H ₁₃ 2
The alcohol form (3.5g, 55%) obtained by reacting tridecafluoropropylene oxide (5.0g, 13.3mmol) and hexanol (8.35ml, 66.5mmol) in the presence of sulfuric acid was converted to SO3-Py complex (2.3g, 14.6 mmol) was reacted in pyridine (12 ml) to give compound 2. The crude product was extracted with acetone using a Soxhlet extractor to remove inorganic salts (3.1 g, 2 steps, 40%).
Colorless amorphous: ¹ H-NMR (CDCl ₃ ): δ0.89 (t, J = 6.8Hz, 3H), 1.15-1.44 (m, 7H), 1.44-1.68 (m, 2H), 2.40-2.86 (m, 2H), 3.32-3.76 (m, 4H), 4.70-5.0 (m, 1H).
IR (KBr, cm ^-1 ): 2936, 1244, 1214, 1150.

Example 3
H (CF ₂ ) ₆ CH ₂ OCH ₂ CH (OSO ₃ Na) CH ₂ OC ₆ H ₁₃ 3
Similarly, Compound 3 was synthesized from dodecafluoroheptyl glycidyl ether (3.88 g, 10 mmol) and hexanol (2.94 g, 30 mmol) (3.1 g, 2 steps, 52%).
Colorless amorphous: ¹ H-NMR (CDCl ₃ ): δ0.89 (t, J = 7.0Hz, 3H), 1.22-1.40 (m, 6H), 1.49-1.60 (m, 2H), 3.43-3.52 (m, 2H), 3.60-3.69 (m, 2H), 3.85 (dd, J = 10.9, 4.4Hz, 1H), 3.92 (dd, J = 10.9, 4.4Hz, 1H), 4.13 (t, J = 14.1Hz, 2H ), 4.45-4.52 (m, 1H), 6.61 (tt, J = 50.8, 4.9Hz, 1H).
IR (KBr, cm ^-1 ): 2938, 1240, 1202, 1142, 1045, 797.

Example 4
H (CF ₂ ) ₈ CH ₂ OCH ₂ CH (OSO ₃ Na) CH ₂ OC ₈ H ₁₇ 4
Similarly, a sulfonic acid ester compound 4 was synthesized in the same manner from an alcohol compound synthesized from hexadecafluoroheptylglycidyl ether (8.06 g, 16.5 mmol) and octanol (13 ml, 82.3 mmol) (5.0 g, 2 steps, 42 %).
Colorless amorphous: ¹ H-NMR (CD ₃ OH): δ 0.89 (t, J = 6.9Hz, 3H), 1.15-1.46 (m, 10H), 1.46-1.65 (m, 2H), 3.48 (t, J = 6.4Hz, 2H), 3.60-3.75 (m, 2H), 3.80-4.00 (m, 2H), 4.16 (t, J = 14.1Hz, 2H), 4.43-4.55 (m, 1H), 6.69 (tt, J = 51.1, 5.1Hz, 1H).
IR (KBr, cm ^-1 ): 2936, 1214, 1149, 1043, 806.

Example 5
H (CF ₂ ) ₆ CH ₂ OCH ₂ CH (OSO ₃ Na) CH ₂ OC ₈ H ₁₇ 5
In the same manner, compound 5 was synthesized from dodecafluoroheptyl glycidyl ether (5.92 g, 15.2 mmol) and octanol (12 ml, 76 mmol) via an alcohol form with a SO3-Py complex (4.2 g, 2 steps, 45%).
Colorless amorphous: ¹ H-NMR (CD ₃ OH): δ0.89 (t, J = 6.9Hz, 3H), 1.17-1.47 (m, 10H), 1.47-1.66 (m, 2H), 3.45 (t, J = 6.4Hz, 2H), 3.60-3.74 (m, 2H), 3.80-4.00 (m, 2H), 4.15 (t, J = 14.1Hz, 2H), 4.43-4.55 (m, 1H), 6.65 (tt, J = 51.1, 5.1Hz, 1H).
IR (KBr, cm ^-1 ): 2936, 1202, 1142, 1043, 796.

Example 6
C ₃ F ₇ OCF (CF ₃ ) CH ₂ OCH ₂ CH (OSO ₃ Na) CH ₂ OCH ₂ CH (C ₂ H ₅ ) C ₄ H ₉ 6
In the same manner, a mixture of 2-ethylhexyl glycidyl ether (6.55 ml, 31.6 mmol) and 2-heptafluoropropoxy-2,3,3,3-tetrafluoropropanol (10.0 g, 32 mmol) was mixed with water at 90 ° C. with stirring. An aqueous sodium oxide solution (NaOH 1.3 g-water 6.3 ml) was added dropwise to react for 6 hours. The reaction solution was extracted with ethyl acetate, the organic phase was dehydrated and the solvent was distilled off to obtain an alcohol form. Further, Compound 6 was synthesized from this alcohol with a SO3-Py complex (6.76 g, 2 steps, 35%).
Colorless liquid: ¹ H-NMR (CD ₃ OH): δ0.80 -1.00 (m, 6H), 1.15-1.65 (m, 9H), 3.34 (d, J = 5.6Hz, 2H), 3.42 (dd, J = 5.1, 1.5Hz, 2H), 3.50-3.76 (m, 2H), 3.76-3.91 (m, 1H), 4.19 (d, J = 11.9 Hz, 2H).
IR (KBr, cm ^-1 ): 2933, 1239, 1150, 998.

Example 7
C ₃ F ₇ OCF (CF ₃ ) CH ₂ OCH ₂ CH (OSO ₃ Na) C ₆ H ₁₃ 7
In the same manner as Compound 5, 1,2-epoxyoctane (4.83 ml, 31.6 mmol), 2-heptafluoropropoxy-2,3,3,3-tetrafluoropropanol (10.0 g, 32 mmol) from the alcohol form, Compound 7 was synthesized with SO3-Py complex (9.8 g, 2 steps, 56%).
Colorless amorphous: ¹ H-NMR (CD ₃ OH): δ0.87 (t, J = 7.0Hz, 3H), 1.15-1.55 (m, 8H), 1.55-1.77 (m, 2H), 3.75-3.89 (m , 2H), 4.08-4.30 (m, 2H), 4.30-4.46 (m, 1H).
IR (KBr, cm ^-1 ): 2936, 1336, 1236, 1151, 997, 936.

Comparative Example 1
(C ₆ F ₁₃ CH ₂ CH ₂ O) ₂ P (O) ONa 8
Compound 8 was synthesized according to J. Am. Chem. Soc. 2002, 124, 1834.
Comparative Example 2
C ₇ F ₁₅ CH (OSO ₃ Na) C ₇ H ₁₅ 9
Compound 9 was synthesized according to J. Phys. Chem. 1992, 96, 6738.

Test example 1
Functional tests of the compounds of Examples and Comparative Examples were performed.
(1) Measurement method of W value and water uptake amount The evaluation value measuring apparatus shown in FIG. 1 was used, and the W value and the water uptake amount were measured according to the following steps 1) to 4).
1) Introduce 2 wt% of a surfactant with respect to carbon dioxide into a part in a pressure-resistant device (view cell) with a visible window.
2) Introduce carbon dioxide to the predetermined measurement pressure and temperature shown in the table, and then introduce water into part a from the six-way valve.
3) The contents were visually observed through a visible window (sapphire window), and it was determined that water was dissolved in carbon dioxide in a transparent and uniform state.
4) The W value and the water uptake amount were calculated from the maximum water introduction amount capable of maintaining a transparent state and the surfactant weight used in the measurement.

The predetermined measurement pressure and temperature of 2) are shown in Table 1 below.
Surfactant effect evaluation (determined by water uptake ability into carbon dioxide)
W value = in micelles (number of water molecules / number of surfactant molecules)
Water uptake = weight of water dissolved in carbon dioxide per gram of surfactant

  So far, compounds 8 and 9 have been reported to have the highest function (J. Am. Chem. Soc. 2002, 124, 1834; Langmuir 1994, 10, 3536). It is described that the amount of water uptake (Water Uptake) per 1 g of the surfactant reaches 1 g. This data is the highest water uptake reported so far. In the present invention, the compounds 2, 3, 5, and 6 are more functional than these.

  Furthermore, when the present inventors synthesized the above compounds 8 and 9 and evaluated them under the same conditions as the compounds of the present invention, although the compound 8 functions at a relatively low pressure, the water uptake of the compound is based on the reported data. Only a fairly low value was obtained.

  Furthermore, since the compound 9 was tested at 50 ° C., it could not function at all. A sample was collected after the test and the cause was sought by instrumental analysis (NMR). A small but very complex peak was observed together with the hydrolyzed sulfate ester moiety (it is considered that the decomposition proceeded even at 50 ° C.). From this result, Compound 9 is considered to be a major obstacle to practical use.

  On the other hand, the compounds of the present invention were found to function stably under the conditions of the evaluation test (samples were collected after the evaluation test and confirmed by instrumental analysis).

  As described above, it was found that the compound of the present invention is an excellent surfactant when a polar compound such as water is used in a medium using carbon dioxide as a solvent.

(A) It is the schematic which shows the measuring apparatus of W value. (B) It is a view cell detail drawing.

Claims (4)

The following general formula (I)

(In the formula, Rf represents a (per) fluoroalkyl group, a (per) fluoroether group, or a (per) fluoropolyether group, and Rh represents an alkyl group.
Y is O, S or NR (R represents a hydrogen atom, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or t-butyl).
p and q are not 0 but 0 or 1 at the same time. )
M represents a hydrogen atom, an alkali metal, 1/2 alkaline earth metal or ammonium. )
A surfactant represented by The surfactant according to claim 1, wherein Rf has 5 to 12 carbon atoms. General formula: RfCH ₂ OCH ₂ CH (OSO ₃ M) CH ₂ ORh
The surfactant according to claim 1 or 2, wherein Rf, Rh and M are as defined above. Use of the surfactant according to any one of claims 1 to 3 for improving the solubility of polar substances in supercritical, subcritical or liquid carbon dioxide.

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