JPS6116269B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved method for producing sulfobetaine. More specifically, the present invention provides a method for producing sulfobetaine at a high reaction rate while reducing the amount of tertiary amine used when reacting a long-chain alkyl tertiary amine with an organic halosulfonate. It is related to. Until now, as a sulfobetaine-type amphoteric surfactant having a long-chain alkyl group, a method has been known in which a halohydroxyalkanesulfonate is reacted with an excess of a long-chain alkyldimethylamine using alcohol or an alcohol-water mixture as the reaction medium. (Japanese Unexamined Patent Publication No. 50-36421). In this method 90
In order to obtain the desired product with a high reaction rate of more than 5%, the tertiary amine is used in an excess amount of about 2 moles or more per mole of halohydroxysulfonate, and the reaction is carried out under pressure at a reaction temperature higher than the boiling point of the reaction medium. It is necessary to do so. Therefore, there is a disadvantage that it is economically disadvantageous in terms of the amount of raw materials used and the equipment used. The present inventors have conducted various studies on methods for obtaining sulfobetaine at a high reaction rate without using an excessive amount of relatively expensive long-chain alkyl tertiary amines and without requiring special conditions such as pressurization. As a result of repeated experiments, it was found that by using water as a solvent and an alkali as a reaction accelerator, even under conditions in which the organic halosulfonate was present in a slight excess, a heterogeneous system formed before the reaction, and tertiary amines were formed as soon as the reaction started. The inventors have discovered that sulfobetaine can be obtained at a high reaction rate because it is dissolved in the reaction system and reacts homogeneously, and based on this knowledge, the present invention has been accomplished. That is, according to the present invention, the general formula (R ₁ in the formula is an aliphatic hydrocarbon group having 8 to 26 carbon atoms,
R ₂ and R ₃ are an alkyl group or a hydroxyalkyl group having 1 to 3 carbon atoms. ) Long _- chain alkyl tertiary amine _{represented by} the general formula halogen atom,
(M is an alkali metal) is reacted with an organic halosulfonate represented by the general formula (In the formula, R ₁ , R ₂ , R ₃ and R ₄ have the same meanings as above.) In the method for producing sulfobetaine represented by (a) water is used as a solvent and the concentration in the reaction system is adjusted to 30
~50% by weight, and (b) the amount of organic halosulfonate used per mole of long-chain alkyl tertiary amine.
and (c) caustic alkali per mole of long-chain alkyl tertiary amine.
By using them together in an amount within the range of 0.11 to 0.25 mol, the desired sulfobetaine can be obtained with a high reaction rate. In this way, in the conventional method, a water-alcohol mixed solvent is used to homogenize the reaction system containing the water-insoluble tertiary amine and the water-soluble sulfonate, whereas the present method In the invention, the conditions of the reaction medium are appropriately selected so that the water-insoluble tertiary amine is dissolved in the reaction system during the reaction. The long-chain alkyl tertiary amine of the general formula () used as a raw material compound in the method of the present invention is such that R ₁ in the general formula () is an aliphatic hydrocarbon group having 8 to 26 carbon atoms, preferably 10 to 22 carbon atoms. So, R ₂ and R ₃ have 1 carbon number
-3 alkyl or hydroxyalkyl groups. This R ₁ may be linear or branched, and may be saturated or unsaturated. Examples of such aliphatic hydrocarbon groups are:
Examples include decyl group, lauryl group, tridecyl group, myristyl group, palmityl group, stearyl group, eicosyl group, docosyl group, and oleyl group. Also,
Examples of R ₂ and R ₃ include methyl, ethyl, propyl, isopropyl, 2-hydroxyethyl, 2-hydroxypropyl, and the like. this
R ₂ and R ₃ may be the same or different. Next, as for the organic halosulfonate of the general formula () which is the other raw material of the method of the present invention, R ₄ in the general formula () is an alkylene group having 2 to 4 carbon atoms or a hydroxyalkylene group, such as -CH ₂ CH ₂ −, −CH ₂ CH ₂ CH ₂ −, −CH ₂ CH ₂ CH ₂ CH ₂ −,

[Formula] or

A divalent hydrocarbon residue represented by the formula: where X is a halogen atom, such as a chlorine atom or a bromine atom,
Those in which M is an alkali metal such as sodium or potassium are used. The organic halosulfonate is preferably 1.1 to 1.5 mol per mol of long-chain alkyl tertiary amine.
It is necessary to use it in a proportion of 1.15 to 1.4 moles. Usually, a high reaction rate of 99% or more is achieved when the usage rate is 1.2 mol or more. If this amount is less than the above range, the reaction rate will decrease, and if it is too much, the content of unreacted organic halosulfonate and its hydrolyzate will increase, leading to a decrease in the purity of the target sulfobetaine. This is not desirable because it causes In the method of the present invention, it is necessary to use a caustic alkali together, and the caustic alkali is preferably sodium hydroxide or potassium hydroxide. Particularly preferred for economic reasons is sodium hydroxide. The caustic alkali is used in an amount of 0.11 to 0.25 mol, preferably 0.12 to 0.2 mol, per mol of long-chain alkyl tertiary amine.
If this amount is less than 0.11 mol, a high reaction rate cannot be obtained, and if it exceeds 0.25 mol, hydrolysis will occur excessively, resulting in a decrease in the reaction rate. As described above, the present invention is characterized in that a specific amount of caustic alkali is used as a reaction accelerator, and water is used as a reaction medium for the reaction even though the raw material is a water-insoluble long-chain alkyl tertiary amine. There is. Thus, in the presence of caustic alkali, out of the competitive alkylation reaction of long-chain alkyl tertiary amines and the hydrolysis reaction of organic halosulfonates in water, the latter becomes dominant. However, if the caustic alkali concentration is appropriately controlled, the reaction rate of the alkylation reaction can be increased and the reaction system can be made homogeneous, so the alkylation reaction can be further promoted and a high reaction rate can be achieved. Become. Therefore, if the amount of caustic alkali used is small, the reaction promoting effect will be small and the reaction rate will not improve, and if the amount of caustic alkali used is too large, the hydrolysis reaction will become too dominant and the reaction rate will decrease. Furthermore, in the method of the present invention, water is used as a reaction solvent, so the reaction system consists of a long-chain alkyl tertiary amine, an organic halosulfonate, a caustic alkali, and water. In this case, the concentration of water in the reaction system is 30 to 50% by weight, preferably 35 to 45% by weight.
It is necessary to control it within a range of weight %. If the amount of water is less than 30% by weight, the reaction mixture will gel, and if it exceeds 50% by weight, the reaction rate will decrease, the homogenization of the system will be insufficient, and side reactions such as hydrolysis will occur. Reactions occur more easily. In the method of the present invention, the reaction can be carried out at a temperature of at least 80°C, usually from 80 to 100°C, so that no particular pressure is required and the reaction can be carried out under normal pressure. Therefore, in order to produce sulfobetaine by the method of the present invention, the long-chain alkyl tertiary amine of the general formula (), the organic halosulfonate of the general formula (), a caustic alkali, and water are mixed in a predetermined ratio. However, it is sufficient to simply carry out a heating reaction. A reaction time of about 3 to 10 hours is usually sufficient. The reaction mixture thus obtained is optionally neutralized with an acid such as sulfuric acid, water is evaporated, the residue is extracted with a suitable solvent such as 2-propanol, and the solvent is distilled off from this extract. Then, the desired sulfobetaine can be isolated. The advantages of the method of the present invention are listed below. (1) Sulfobetaine can be produced with high reaction rate. (2) Since the reaction occurs in an aqueous medium, no organic solvent is mixed into sulfobetaine. For example, alcohol has a negative effect on foaming properties, but in the present invention, only water is used, so there is no need to worry about this. (3) Since the organic halosulfonate is used in a slight excess based on the tertiary amine, the residual amount of the amine is small, and there is no need for purification when using it as a cleaning agent. (4) Since there is no need to pressurize, the reactor can be simple. Utility costs can be reduced because there is no need to raise the reaction temperature too high. Next, the present invention will be explained in more detail with reference to Examples. Example 1 Equipped with stirrer, thermometer and reflux condenser
Put 97.8 g (0.45 mol) of dodecyldimethylamine into a 500 ml four-necked flask, add 106.4 g (0.54 mol) of sodium 2-hydroxy-3-chloropropanesulfonate (hereinafter abbreviated as quaternizing agent),
Sodium hydroxide 2.25g (0.056mol) and water
Add 136.1g (concentration of water 40% by weight) and heat at 85°C.
Allowed time to react. The reaction rate for tertiary amines is
It was 99 mol%. Example 2 Sulfobetaine was produced in exactly the same manner as in Example 1, except that the amount of sodium hydroxide was varied in the range of 0 to 9.0 g (molar ratio to amine 0 to 0.5). At this time, the reaction rate for tertiary amine is
Shown in the table. In addition, experiment numbers 1, 2, and 9 in the table are comparative examples, and experiment number 5 is Example 1.

[Table] Example 3 The experiment of Example 1 was repeated by changing the molar ratio of organic halosulfonate to tertiary amine, the concentration of water in the reaction system, and the reaction temperature. The results are shown in Table 2. In addition, experiment numbers 5 to 7 in the table are comparative examples.

【table】

Claims (1)

[Claims] 1. General formula (R ₁ in the formula is an aliphatic hydrocarbon group having 8 to 26 carbon atoms,
_{R 2} and R ₃ are alkyl groups or hydroxyalkyl groups having 1 to ₃ carbon _atoms . Number 2 to 4 alkylene group or hydroxy-substituted alkylene group, X is a halogen atom, M
is an alkali metal) with an organic halosulfonate represented by the general formula In the method for producing sulfobetaine represented by the formula (R ₁ , R ₂ , R ₃ and R ₄ have the same meanings as above), (a) water is used as a solvent and the concentration in the reaction system is adjusted to 30 ~50
(b) The amount of the organic halosulfonate to be used is selected within the range of 1.1 to 1.5 mol per 1 mol of long-chain alkyl tertiary amine, and (c) The caustic alkali is A method for producing sulfobetaine, characterized in that it is used in combination in an amount within the range of 0.11 to 0.25 mol per 1 mol of sulfobetaine. 2. The method according to claim 1, wherein the reaction is carried out at a temperature of 80 to 100°C.