JPH04217972A - New carboxylic acid salt derivative and decomposable surfactant made thereof - Google Patents

Abstract

PURPOSE:To provide a new carboxylic acid salt derivative having bio- degradability as well as chemical degradability, exhibiting excellent environmental safety and useful as a decomposable surfactant. CONSTITUTION:A carboxylic acid salt derivative of formula I (R<1> is 6-30C alkyl or alkylaryl; R<2> is 1-17C alkyl or alkyloxyalkylene; R<3> is 0-7C alkylene; n is 1 or 2; M<n+> is alkali metal ion or ammonium ion when n=1 and is alkaline- earth metal ion when n=2). The compound of formula I can be produced by condensing a 1-0-alkylglycerol of formula II with a keto acid ester of formula III in the presence of an acid catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a novel carboxylate derivative and a degradable surfactant comprising the same.

Background Art Surfactants have functions such as emulsifying, dispersing, solubilizing, foaming, and cleaning in aqueous solutions or organic solvent solutions, and are widely used in various fields. For example, when an organic synthesis reaction is carried out using a medium based on an aggregate of surfactant molecules such as micelles, reverse micelles, and microemulsions, such as emulsion polymerization, which is already carried out industrially. , it has advantages such as enabling reaction control that cannot be achieved with ordinary solvent systems.

However, when the reaction is carried out in the presence of a surfactant as described above, on the other hand, it is difficult to isolate the target substance if the emulsion system remains after the reaction, and the quality of the target substance remains. There are problems such as a decrease depending on the surfactant used. Therefore, in the past, so-called degradable surfactants, which have the property of decomposing under as mild conditions and losing their surface activity after fulfilling their role as surfactants, have been strongly used in various fields. It is requested.

On the other hand, household and industrial detergents account for a considerable proportion of the consumption of surfactants, not only in Japan but also worldwide, and the amount of surfactants that are released into rivers and lakes after use is Consideration of environmental issues is required.

Soap is more biodegradable than linear alkylbenzene sulfone salts (LAS), which are the main ingredients in synthetic detergents, and should be reconsidered from the perspective of its impact on the environment, but its actual cleaning power is The reality is that synthetic detergents are inferior to synthetic detergents, and they also have fundamental problems such as the formation of soap scum, so their use as substitutes for synthetic detergents is currently extremely limited.

Therefore, various biodegradable and chemically degradable surfactants, particularly acetal-type degradable surfactants, have been proposed. For example, those obtained by the reaction of aliphatic aldehydes and polyethylene glycols (Kuwamura et al.
Bull. Chem. Soc. Japan, 45, 61
7 (1972)), 1,3-dioxane or 1,3-dioxolane derivatives obtained by the reaction of aliphatic aldehydes or ketones with glycerol (Burc.
Zyk et al. , Tenside Surfa
c-tants Deterg. , 17, 21 (198
0)), 1,3- by reaction of markanediols with chloroketones and subsequent reaction with tertiary amines.
Quaternary ammonium salt type containing dioxolane ring (
Jaeger et al. , J. Org. Chem
．． , 47, 33 (1982)) have been proposed.

However, such conventional acetal-type degradable surfactants lack hydrophilicity as they are, or they require multiple steps to introduce ionic hydrophilic groups due to the availability and cost of raw materials. However, there are still many problems in terms of

Problems to be Solved by the Invention The present invention was made to solve the above-mentioned problems with conventional degradable surfactants, and has both biodegradability and chemical degradability, and is environmentally safe. Excellent, even more
From the viewpoint of its production, it uses l-O-alkylglycerols and keto acid esters that are easily available as natural product-derived products or synthetic products as raw materials, and can be easily operated without the need for special reagents or equipment. An object of the present invention is to provide a novel acetal-type decomposable carboxylate derivative that can be produced in high yield by a method of the present invention, and a surfactant comprising the same.

Means for Solving the Problems The novel carboxylate derivative according to the present invention has the general formula (wherein R1 is an alkyl group or alkylaryl group having 6 to 30 carbon atoms, R2 is an alkyl group having 1 to 17 carbon atoms, Alkyloxyalkylene group, R3 represents an alkylene group having 0 to 7 carbon atoms, n represents an integer of 1 or 2, and n is 1
When n is 2, Mn+ represents an alkali metal ion or an ammonium ion, and when n is 2, an alkaline earth metal ion is represented. ).

In the above, an alkylene group having 0 carbon atoms has the same meaning as a carbon-carbon bond.

Further, the degradable surfactant according to the present invention is characterized by being composed of the above-mentioned carboxylate derivative.

The above-mentioned novel carboxylate derivative according to the present invention comprises a l-O-alkylglycerol represented by the general formula (wherein R1 is the same as above) and a l-O-alkylglycerol represented by the general formula (wherein R2 and R3 are the same as above). and R4 represents an alkyl group) are condensed and acetalized in the presence of an acid catalyst to form a reaction intermediate of the general formula (where R1, R2, R3 and R4 is the same as above) is obtained, and then the ester group contained in this carboxylic ester is alkyl hydrolyzed to convert it into a carboxylic acid salt.

As the l-O-alkylglycerol represented by the above general formula (II), batyl alcohol (l-O-octadecylglycerol) and chimyl alcohol (l-O-hexadecyl Naturally derived products such as glycerol) and serachyl alcohol (l-O-oleylglycerol) can be used as they are.

In addition, various types obtained by hydrolysis after Williamson's ether synthesis reaction of 1,2-O-isopropylideneglycerol or 1,2-O-benzylideneglycerol and alkyl halide or alkyl tosylate, etc. 1-O-alkylglycerol having an alkyl group can also be suitably used.

In the keto acid ester represented by the general formula (III), R4 is an alkyl group, and is not particularly limited, but lower alkyl groups such as a methyl group and an ethyl group are usually preferably used. .

Examples of such keto acid esters include levulinic acid ethyl ester, which is obtained by heating hexose and sucrose containing hexose as a structural unit, starch, cellulose, etc., with dilute mineral acid. -keto acid esters,
β-keto acid esters such as acetoacetic acid methyl ester and ethyl ester, α-keto acid esters such as pyruvic acid, which are easily available as industrial products;
δ that can be produced by already known methods
- and higher keto acid esters can be used.

Therefore, in addition to the examples given above, examples of γ-keto acid esters and higher keto acid esters include levulinic acid methyl ester and 5-ketohexanoic acid, and β-keto acid esters include For example, 3-
Keto-n-butyric acid ethyl ester, 3-keto-n-hexanoic acid ethyl ester, 3-oxoenanthioic acid ethyl ester, 4,4-dimethyl-3-oxoacetic acid methyl ester, 4,4-dimethyl-3-oxobutyric acid Ethyl ester, 3-keto-5-methoxyacetic acid methyl ester, 2-
Examples include ethyl methylacetoacetate, ethyl 2-n-butylacetoacetate, and ethyl n-hexylacetoacetate.

In addition, examples of α-keto acid ester include pyruvic acid methyl ester, 2-oxoacetic acid ethyl ester, 2-oxoacetic acid ethyl ester,
-Oxovaleric acid ethyl ester, 2-oxohexanoic acid ethyl ester, etc. can be mentioned.

In the above reaction of l-O-alkylglycerol and keto acid ester, l-O-alkylglycerol is
It is used in at least an equivalent amount, preferably in a range of 1.1 to 1.3 equivalents, based on the keto acid ester.

The reaction is preferably carried out in an organic solvent that forms an azeotrope with water, such as benzene or toluene, using a conventional acetalization catalyst, such as an acid catalyst such as a mineral acid, a Lewis acid, an organic sulfonic acid, etc. In the presence of Dean. Stark (D
The reaction is carried out by heating the solution under normal pressure under reflux conditions while removing condensed water generated as the reaction progresses in a (Ean-Stark) trap.

In this way, after a predetermined amount of condensed water is produced in the reaction, the reaction system is cooled to around room temperature, the reaction solution is washed with a weakly alkaline aqueous solution and then with water, and then the solvent is distilled off. As a reaction intermediate, a carboxylic acid ester containing a 5-alkyloxymethyl-1,3-dioxolane ring represented by the general formula (IV) is obtained. This crude carboxylic acid ester can be purified by distillation under reduced pressure.

Next, this carboxylic acid ester is heated in an aqueous solution of an alkali metal hydroxide such as sodium or potassium or an alkaline earth metal hydroxide such as calcium or magnesium, or a solution of a lower alcohol such as methanol or ethanol, to form an alkali under heating. After hydrolysis and reaction,
By distilling off the solvent, the desired acetal type carboxylate derivative can be obtained with a high yield of usually 80% or more. This acetal type carboxylate derivative is
If necessary, it can be purified by recrystallization from a solvent such as ethanol.

Incidentally, the carboxylic acid ester obtained as the reaction intermediate can be directly subjected to alkaline hydrolysis without being purified and isolated to obtain the carboxylic acid salt derivative according to the present invention.

Effects of the Invention Since the carboxylate derivative according to the present invention is a type of soap, it has good biodegradability, is stable under neutral and alkaline conditions, and has far better water solubility than ordinary soap. It also has excellent surface activity. On the other hand, under acidic conditions above a certain level, the acetal moiety of the 1,3-dioxolane ring in the molecule is easily chemically decomposed, and in particular,
In a preferred embodiment of the present invention, when naturally derived materials are used as raw materials, each naturally derived initial l-
Returning to the non-surfactant components of O-alkylglycerol and keto acids. Therefore, the carboxylic acid derivative according to the invention is
Very useful as a degradable surfactant.

Furthermore, in a preferred embodiment of the present invention, the calcium salts of levulinic acid and acetoacetic acid produced as a result of the acid decomposition are easily soluble in water and have better hard water resistance than soap. Therefore, when the carboxylic acid salt derivative according to the present invention is used as a detergent, it has the advantage that soap scum caused by calcium soap, which is a problem with ordinary soap, is not easily generated.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples in any way.

In the following, the surface tension of the sample aqueous solution is measured under slightly alkaline conditions of pH 11, usually at 20°C, using the Wilhelmy glass plate method or Duneuulli's platinum ring method.
Critical micelle concentration (CMC) and surface tension lowering ability (γCMC) were determined from a plot of the relationship between surface tension and logarithmic concentration. Degradability under acidic conditions was determined by the method published by the present inventors (Ono, Masuyama, Okahara, J. Org. Chem., 55,
4461 (1990), using superconducting proton nuclear magnetic resonance spectroscopy.

Example 1 In general formula (I), R1=C10H21, R2=C
Synthesis of compounds where H3, R3 = (CH2)2, n = 1, Mn+ = Na+ In a 300 ml volumetric round bottom flask, 3-decyloxy-1,
2-propanediol 25.5g (0.11mol),
14.4 g (0.1 mol) of ethyl levulinate, 0.9 g (5 mol%) of p-toluenesulfonic acid, and 150 ml of toluene were charged, a Dean-Stark trap was connected, and the reaction was carried out under reflux conditions for 1 hour. Approximately 1.8 ml of condensed water was observed in the trap.

The reaction solution was transferred as it was to a separatory funnel, washed sequentially with 150 ml of a 5% aqueous sodium hydrogen carbonate solution, 150 ml of water, and 100 ml of saturated saline, and after drying the toluene layer over anhydrous sodium sulfate, the solvent was distilled off. 35.1 g of a crude ethyl ester product as a reaction intermediate was obtained as a colorless liquid (yield 98%).

Those purified by vacuum distillation have a boiling point of 125-127℃/
It was 0.05 Torr. Purification yield 95%.

35.1 g of the above ethyl ester crude product was charged into a 300 ml round bottom flask, and sodium hydroxide (95%)
．． 6g (0.11mol) methanol (100ml)
The solution was added and heated to reflux for 30 minutes. Thereafter, methanol was distilled off, hot ethanol was added to the product, insoluble matter was filtered off while hot, and ethanol was distilled off from the filtrate to obtain 32.4 g of a white waxy solid as the desired product. Overall yield 92%
.

Spectral data and properties of this compound are shown below.

Infrared spectrum (neat) ν2900, 1560, 1120 cm-1.

Proton nuclear magnetic resonance spectrum (CDCl3, internal standard TMS) δ0.88 (t, 3H), 1.20-1.40 (m-s
, 14H-3H), 1.57 (m, 2H), 1.95 (
t, 2H), 2.25 (t, 2H), 3.45-3.8
0 (m, 5H), 4.05 (m, 1H), 4.30 (m
, 1H).

Elemental analysis value (calculated value) C: 60.98 (61.34), H: 9.34 (9.4
4).

Solubility Soluble in water at 0°C or higher at a concentration of 1% by weight or less (pH 11) 2.3 x 10-3 M γCMC 33.0 mN/m Acid decomposability In an aqueous solution with pH 3, the carboxylate was neutralized. However, there was almost no change even after one week, and the molecular structure was maintained. In an aqueous solution of pH 1, it was almost completely decomposed after about 80 minutes.

Examples In general formula (I), R1=C18H37, R2=C
Synthesis of a compound where H3, R3=(CH2)2, n=1, Mn+=Na+ In the same manner as in Example 1, 37.8 g of batyl alcohol (
0.11 mol), ethyl levulinate 14.4 g (0.11 mol), ethyl levulinate 14.4 g (0.
1 mol) and p-toluenesulfonic acid 0.9 g (5 m
ol%) was heated under reflux in 500 ml of toluene for 1 hour.

Add toluene solution to 150ml of 5% sodium bicarbonate aqueous solution
1, washed sequentially with 150 ml of water and 100 ml of saturated brine, dried over anhydrous sodium sulfate, and then distilled off the solvent to obtain a crude ethyl ester product 45.7 ml as a reaction intermediate.
g was obtained as a colorless solid (yield 98%).

45.7 g of the above crude ethyl ester product was heated under reflux for 30 minutes in a solution of 4.6 g (0.11 mol) of sodium hydroxide (95%) in methanol (100 ml). Thereafter, it was treated in the same manner as in Example 1, and 39.6 g of white solid was obtained.
was obtained as a target. Overall yield 86%.

This target product was purified by recrystallization from ethanol. Melting point: 147-150°C Purification yield: 80%.

Spectral data and properties of this compound are shown below.

Infrared absorption spectrum (KBr) ν2900, 1560, 1120 cm-1.

Proton nuclear magnetic resonance spectrum (CD3OD, internal standard TMS) δ0.88 (t, 3H), 1.20-1.40 (m-s
, 30H + 3H), 1.57 (m, 2H), 1.95 (
t, 2H), 2.25 (t, 2H), 3.45-3.8
0 (m, 5H), 4.05 (m, 1H), 4.30 (m
, 1H).

Elemental analysis value (calculated value) C: 67.25 (67.21), H: 10.32 (10
．． 63).

Solubility Soluble in water at 0°C or higher at a concentration of 0.1% by weight or less (pH 1
1) CMC 8.5×10-6M γCMC 34.0mN/m In an acid-decomposable pH 3 aqueous solution, the carboxylic acid salt was only neutralized, and there was almost no change even after one week, and the molecular structure was maintained. was. In an aqueous solution of pH 1, it was almost completely decomposed after about 80 minutes.

Example 3 In general formula (I), R1=C16H33, R2=C
Synthesis of a compound where H3, R3=CH2, n=1, Mn+=Na+ In the same manner as in Example 1, chimyl alcohol 3
4.8g (0.11mol), ethyl acetoacetate 13g
(0.1 mol) and p-toluenesulfonic acid 0.9 g
(5 mol%) was heated under reflux in 150 ml of toluene for 1 hour.

Add toluene solution to 150ml of 5% sodium bicarbonate aqueous solution
1, washed sequentially with 150 ml of water and 100 ml of saturated brine, dried over anhydrous sodium sulfate, and then distilled off the solvent to obtain a crude ethyl ester product 40.2 as a reaction intermediate.
g was obtained as a colorless solid (yield 94%).

40.2 g of the above crude ethyl ester product was heated under reflux for 30 minutes in a solution of 4.6 g (0.11 mol) of sodium hydroxide (95%) in methanol (100 ml). Thereafter, it was treated in the same manner as in Example 1, and 39.5 g of white solid was obtained.
was obtained as a target. Overall yield 85%.

This target product was purified by recrystallization from ethanol. Melting point 60-62°C. Purification yield 81%.

Spectral data and properties of this compound are shown below.

Infrared absorption spectrum (KBr) ν2900, 1570, 1120 cm-1.

Proton nuclear magnetic resonance spectrum (CD3OD, internal standard TMS) δ0.88 (t, 3H), 1.20-1.40 (m, 2
6H), 1.50-1.60 (m+s, 2H+3H),
2.65 (d, 2H), 3.30-3.65 (m, 4H
), 3.80 (m, 1H), 4.05 (m, 1H)4.
30 (m, 1H).

Elemental analysis value (calculated value) C: 65.01 (65.37), H: 10.57 (10
．． 26).

Solubility Soluble in water at 0°C or higher at a concentration of 1% by weight or less (pH 11) CMC 5.0 x 10-4M γCMC 35.0 mN/m Acid decomposability Almost completely dissolved in an aqueous solution with pH 1 after about 80 minutes Disassembled.

Example 4 In general formula (I), R1=C16H33, R2=C
H3, R3=(CH2)0, i.e. carbon-carbon bond, n=1
, Mn+=Na+ In the same manner as in Example 1, 38.0 g of chimyl alcohol (
0.12 mol), ethyl pyruvate 11.6 g (0.12 mol), ethyl pyruvate 11.6 g (0.
1 mol) and p-toluenesulfonic acid 0.9 g (5 m
ol%) was heated under reflux in 200 ml of toluene for 1 hour and 30 minutes.

Toluene was distilled off under reduced pressure, and 15% of chloroform was added to the residue.
Add 0 ml and 150 ml of 5% sodium hydrogen carbonate aqueous solution.
1 and 100 ml of saturated saline solution, dried over anhydrous magnesium sulfate, and then the solvent was distilled off. The resulting residue was mixed with 4.6 g (0.1
1 mol) of methanol (100 ml) and heated under reflux for 30 minutes. Thereafter, it was treated in the same manner as in Example 11 to obtain 37.5 g of a white solid as the desired product. Overall yield 92%.

This target product was purified by recrystallization from ethanol. Melting point 54-56°C. Purification yield 81%.

Spectral data and properties of this compound are shown below.

Infrared absorption spectrum (KBr) ν2900, 1580, 1100 cm-1.

Proton nuclear magnetic resonance spectrum (CD3OD, internal standard TMS) δ0.88 (t, 3H), 1.20-1.40 (m, 2
6H), 1.50-1.65 (m+s, 2H+3H),
3.30-3.65 (m, 4H), 4.10 (m, 1H
), 4.30 (m, 2H).

Elemental analysis value (calculated value) C: 64.35 (64.68), H: 10.31 (10
．． 12).

Solubility Soluble in water at 0°C or higher at a concentration of 1% by weight or less CMC 7.5 x 10-4 M γCMC 35.5 mN/m Acid decomposability Almost completely decomposed after about 80 minutes in an aqueous solution with pH 1 Example 5 In general formula (I), R1=C16H33, R2=C
Synthesis of a compound where H3, R3=CH2n=2, Mn+=Ca2+ 20.1 g of the reaction intermediate ethyl ester crude product in Example 3 was mixed with 1.4 g of calcium hydroxide (0.0
25 mol) in methanol (50 ml) and heated under reflux for 30 minutes. Thereafter, the generated solid was filtered, washed with hot ethanol, and dried to obtain 19.5 g of a white solid as the target product. Total yield based on ethyl acetoacetate: 87
%. Melting point: 135-140°C.

Spectral data and properties of this compound are shown below.

Infrared absorption spectrum (KBr) ν2900, 1590, 1120 cm-1.

Elemental analysis value (calculated value) C: 65.37 (65.83), H: 10.67 (10
．． 33).

Solubility Virtually insoluble in water. Soluble in dimethylformamide at concentrations below 0.01% by weight.

Example 6 In general formula (I), R1=C16H33, R2=C
H3, R3=CH2, n=1, Mn+=H3N+CH2
Synthesis of compound that is CH2OH 10.5 g (0.025 mol) of carboxylic acid sodium salt, the final product in Example 3, was dissolved in 100 ml of water, neutralized by adding 0.25 ml of 0.1N hydrochloric acid, and 200 ml of ether. Extracted three times. After drying the ether solution over anhydrous magnesium sulfate, the solvent was distilled off to obtain 9.2 g of free acid as a white wax.

Next, 9.2 g of the above free acid was added to 1.5 g of ethanolamine.
(0.025 mol) in methanol (50 ml) and stirred at room temperature for 30 minutes. Thereafter, methanol and excess ethanolamine were distilled off under reduced pressure, and pale yellow solid 9.
．． 8 g of the desired product was obtained. Yield 85%.

This target product was purified by recrystallization from ethanol. Melting point 35-38°C. Purification yield 75%.

Spectral data and properties of this compound are shown below.

Infrared absorption spectrum (KBr) ν3350, 3100, 2900, 1600, 1550
, 1430, 1120 cm-1.

Proton nuclear magnetic resonance spectrum (CD3OD, internal standard TMS) δ0.88 (t, 3H), 1.20-1.40 (m, 2
6H), 1.50-1.65 (m s, 2H 3H),
2.65 (d, 2H), 3.05 (s, 1H), 3.3
0-3.65 (m, 8H), 3.80 (m, 1H), 4
．． 05 (m, 1H), 4.30 (m, 1H), 9.0-
10.0 (br, 3H).

Elemental analysis value (calculated value) C: 64.51 (65.04), H: 11.47 (11
．． 13) Solubility Soluble in water at 0°C or above at a concentration of 1% by weight or less Each was almost completely decomposed after about 10 minutes in the aqueous solution.

Claims (2)

[Claims] Claim 1: General formula (wherein R1 is an alkyl group or alkylaryl group having 6 to 30 carbon atoms, R2 is an alkyl group or alkyloxyalkylene group having 1 to 17 carbon atoms, and R3 is an alkyl group having 0 to 7 carbon atoms. represents an alkylene group, n represents an integer of 1 or 2, and n represents 1
When n is 2, Mn+ represents an alkali metal ion or an ammonium ion, and when n is 2, an alkaline earth metal ion is represented. ) A carboxylate derivative represented by Claim 2: General formula (wherein R1 is an alkyl group or alkylaryl group having 6 to 30 carbon atoms, R2 is an alkyl group or alkyloxyalkylene group having 1 to 17 carbon atoms, and R3 is an alkyl group having 0 to 7 carbon atoms. represents an alkylene group, n represents an integer of 1 or 2, and n represents 1
When n is 2, Mn+ represents an alkali metal ion or an ammonium ion, and when n is 2, an alkaline earth metal ion is represented. ) A degradable surfactant consisting of a carboxylate derivative represented by: