JPH033720B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for purifying amphoteric surfactants. Amphoteric surfactants generally have the advantage of mild irritation to the skin and eyes and can be used in a wide range of pH ranges, but they usually avoid contamination with inorganic salts such as sodium chloride and sodium sulfate derived from manufacturing. As a result, the following problems often occur, especially in detergent compositions such as shampoo. In other words, the use of amphoteric surfactants is severely restricted because problems such as decreased low-temperature stability, inability to stably obtain a desired viscosity, and demulsification breakage occur due to the influence of inorganic salts. ing. There has long been a desire for the emergence of amphoteric surfactants that do not contain salts, but because amphoteric surfactants have anionic and cationic charges in their molecules, they differ from anionic surfactants and cationic surfactants. , pH
Because it remains stable in water even when the temperature is varied, isolation and purification is extremely difficult. In the laboratory, it is possible to remove salts by adding a large amount of organic solvent to precipitate them, or to desalt them using ion exchange resin, but these methods are both complicated and disadvantageous in terms of cost. It will never be adopted industrially. Regarding the purification of amphoteric surfactants, as a result of intensive studies on purification methods that are simple and industrially applicable, the present inventors found that an amphoteric surfactant aqueous solution or suspension containing inorganic salts contains an alcohol that is sparingly soluble in water, That is, they discovered that the desalted amphoteric surfactant can be extracted extremely efficiently by adding a saturated or unsaturated alcohol having 4 to 10 carbon atoms to the alcohol phase, and have completed the present invention. Ivy. Next, to describe the present invention in more detail, inorganic salts that can be used in the purification method of the present invention include:
These are inorganic salts of alkali metals and alkaline earth metals such as Na, K, Ca, and Mg with hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and boric acid, and the alcohol used has 4 carbon atoms.
to 10 saturated or unsaturated aliphatic or alicyclic alcohols, such as butanol, pentanol, hexanol, heptanol, octanol, decanol, 2-ethylhexanol, 2-ethyloctanol, cyclopentanol, cyclohexanol, etc. Can be mentioned. Alcohols with less than 3 carbon atoms are easily soluble in water, making it difficult to separate them from the aqueous phase, while alcohols with more than 10 carbon atoms have too high a boiling point and solidify at low temperatures, making them difficult to handle. is undesirable because it increases As the amphoteric surfactant used in the present invention, any amphoteric surfactant can be used, but the following amphoteric surfactants are particularly suitable. 1 N-acyl-α-amino acid type represented by the general formula [], [] (However, in the formula, RCO is a fatty acid residue having 8 to 22 carbon atoms). 2 Carboxybetaine type represented by the general formula [], []

【formula】

[Formula] (However, in the formula, R ₁ is an alkyl group having 8 to 22 carbon atoms or an alkenyl group, and R ₂ , R ₃ , and R ₄ are each an alkyl group having 1 to 3 carbon atoms) 3 General formula [], [ Imidazoline type represented by ], [], [] (However, in the formula, R ₁ is about 4 to 18 alkyl or alkenyl groups, R ₂ is 1 to 4 alkylene groups, R ₃ is R ₂ or an alkylene group substituted with an OH group, M is a hydrogen atom, an alkali cations derived from metals or alkanolamines;
and G is an anion) 4 Amidamine type represented by general formulas [] and [] (However, in the formula, R ₁ is an alkyl group or alkenyl group having about 8 to 22 carbon atoms, and R ₂ is -
CH ₂ COOM or −CH ₂ CH ₂ COOM, R ₃ is hydrogen,
-CH ₂ COOM or -CH ₂ CH ₂ COOM, M is a cation that forms a water-soluble salt) (However, in the formula, R ₁ , R ₂ , R ₃ have the same meanings as the symbols in the general formula [], R ₄ is hydrogen, -
CH ₂ COOM or -CH ₂ CH ₂ COOM, M has the same meaning as the symbol in general formula []) 5 Amidobetaine type represented by general formula [XI] (However, in the formula, RCO is a fatty acid residue having 8 to 22 carbon atoms, R ¹ and R ² are alkyl groups having 1 to 3 carbon atoms.) The purification method of the present invention is extremely simple and can be performed using a conventional extraction method. good. That is, a saturated or unsaturated alcohol having 4 to 10 carbon atoms is added to an aqueous solution containing an amphoteric surfactant and an inorganic salt, especially a suspension, and after thorough stirring, the phases are separated and the alcohol phase is separated. A desalted amphoteric surfactant can be obtained by concentration. The concentrations of the amphoteric surfactant and the inorganic salt in the aqueous solution or suspension are not particularly limited, but preferably a total of 50% or less gives good results.
In addition, to confirm the purification of the amphoteric surfactant of the present invention, take a certain amount of the phase-separated alcohol phase or concentrated dry product of the alcohol phase, quantify the metal ions contained by atomic absorption spectrometry, and check the inorganic salt content. This can be done by finding . On the other hand, the obtained amphoteric surfactant can be quantified by taking the alcohol phase after phase separation or by taking a certain amount of the alcohol phase and quantifying it by high performance liquid chromatography, or by combining the weight of the concentrated dry product of the alcohol phase with the above-mentioned method. It can be determined from the difference in the weight of the inorganic salt determined by the method. Hereinafter, this will be explained in detail using examples. Example 1 Take 10 g of amphoteric surfactant and 1.0 g of NaC1, add 100 ml of water to dissolve or suspend it, and then
- Add 100 ml of butanol and stir at room temperature for about 3 hours. After standing and phase separation, the n-butanol phase was taken, and 100 ml of water was added again for extraction, and the n-BuOH phase was concentrated to dryness under reduced pressure. Then, it is placed in a dryer heated to 80°C and thoroughly dried under reduced pressure. The recovery rate of the dried amphoteric surfactant was determined by high performance liquid chromatography, and the content of NaCl in the amphoteric surfactant was determined by atomic absorption spectrometry. The results are shown in Table 1.

【table】

[Table] *1 Quantitative method: Measured using high performance liquid chromatography.
[Conditions] Column: Fenesil C ₁₈ (4φ x 25cm) Temperature: 40℃ Flow rate: 10ml/min Pressure: 70Kg/cm ² wavelength: 210nm Solvent: 0.03M-NaH ₂ PO ₄ /MeOH (1:9) *2 Quantification Method: Measured by gravimetric method. After concentrating the n-butanol phase to dryness and thoroughly drying it,
Obtained by measuring weight and atomic absorption spectrometry
The value obtained by subtracting the amount of NaCl was defined as the recovery rate. Example 2 Take 10 g of amphoteric surfactant and 2.0 g of Na ₂ SO ₄ and add 100 ml of water to dissolve or suspend it.
Add 100 ml of cyclohexanol and perform the same operation as in Example 1 to remove the
Na ₂ SO ₄ was determined. The results are shown in Table 2.

【table】

[Table] Example 3 Take 10 g of an amphoteric surfactant and 2.5 g of Na ₂ SO ₄ , add 25 ml of water to dissolve or suspend it, then add 125 ml of hexyl alcohol and perform the same operation as in Example 1 to obtain an amphoteric interface. The recovery rate of the active agent and the Na ₂ SO ₄ contained in the amphoteric surfactant were determined. The results are shown in Table 3.

【table】

[Table] Example 4 40 ml of water and 40 ml of acetone are added to 4.21 g (20 mmol) of N ^{a ,} N a -dimethyllysine hydrochloride and dissolved by stirring at room temperature. Then lauroyl chloride
4.81g (22mmol) in 10%-NaOH pH 11.0
While keeping it nearby, slowly lower the dose to perform the Schotten-Baumann reaction. After neutralization with 10% HCl, the reaction solution is gradually heated and acetone is completely distilled off at normal pressure, and then 70 ml of n-butanol is added and thoroughly stirred at room temperature for extraction. After standing and phase separation, take the n-butanol phase, add 50 ml of water again, stir in the same way, leave to separate the phases, and concentrate the obtained n-butanol phase to dryness under reduced pressure. −N〓、
6.9 g of N-dimethyllysine was obtained in a yield of 97%.
Note that the content of NaCl in the crystals was 1% or less.

Claims (1)

[Claims] 1. An amphoteric interface characterized by using a saturated or unsaturated alcohol having 4 to 10 carbon atoms as an extraction solvent when purifying an amphoteric surfactant aqueous solution or suspension containing inorganic salts. Method for purifying activators. 2. The purification method according to claim 1, wherein the alcohol is butanol, pentanol, hexanol, heptanol, octanol, decanol, 2-ethyl octanol, cyclopentanol, or cyclohexanol.