JPH035453A - Production of alkylbiphenyldisulfonic acid salt - Google Patents

Abstract

PURPOSE:To obtain the subject compound by a pale color which is excellent in solubility in a highly concentrated aqueous solution of electrolyte and useful as a surfactant usable over a wide range of applications by sulfonation of an alkylbiphenyl with sulfuric anhydride under specific conditions. CONSTITUTION:An alkylbiphenyl having 10-20C monoalkyl group is sulfonated with sulfuric anhydride at <=30 deg.C in a 1-2C aliphatic halogenated hydrocarbon solvent (e.g. 1,2-dichloroethane) followed by addition of water and then distilling and recovering the solvent, thus obtaining the objective compound. The amount of the solvent to be used is 1-20 pts.wt. per pt.wt. of the alkylbiphenyl, the molar ratio of the sulfuric anhydride to the alkylbiphenyl being 1.8-2.5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing an alkyl biphenyl disulfonate. Alkylbiphenyl disulfonates are widely used as surfactants due to their solubility in highly concentrated electrolyte aqueous solutions.

[Conventional technology]

It is well known that when alkylbenzenes are sulfonated with sulfuric anhydride to produce alkylbenzene sulfonates, alkylbenzenes and sulfuric anhydrides are directly reacted without a solvent. Furthermore, JP-A-63-145263 describes a method for sulfonating alkylbiphenyl using n-hexane as a solvent.

[Problem to be solved by the invention]

When performing the sulfonation reaction of alkylbiphenyl without using a solvent as in the conventionally known method described above, for example, the sulfonation reaction of alkyl biphenyl is carried out without using a solvent, the viscosity of the reaction solution increases rapidly during the reaction, and stirring becomes difficult. cannot be carried out sufficiently, and the disulfonation reaction stops midway. If sulfuric anhydride is further added and the reaction is forced to continue, the reaction product will become more intensely colored, and eventually some portions will be carbonized.

When n-hexane is used as the reaction solvent as in JP-A-63-145263, stirring is continued until the disulfonation reaction is completed, but the alkyl biphenyl disulfonate obtained by this method is not colored. This is so large that it cannot be accepted as a commercial surfactant as it is, and requires a separate purification process.

Furthermore, if the molar ratio of sulfuric anhydride to the raw material alkyl biphenyl is reduced in order to obtain a light-colored alkyl biphenyl disulfonate, a problem arises in that a sufficient disulfonation reaction rate cannot be obtained.

[Means to solve the problem]

The present invention provides a method for producing an alkyl biphenyl disulfonate by sulfonating an alkyl biphenyl with sulfuric anhydride, in which an alkyl biphenyl having a monoalkyl group having 10 to 20 carbon atoms is used as a reaction solvent to form an aliphatic compound having 1 to 2 carbon atoms. Using 1 to 20 parts by weight of halogenated hydrocarbon per 1 part by weight of alkyl biphenyl, the reaction temperature is 30°C or less, and the molar ratio of sulfuric anhydride to alkyl biphenyl is 1.8 to 20.
The present invention provides a method for producing a light-colored alkyl biphenyl disulfonate, which is characterized by carrying out a sulfonation reaction in a range of 2.5, adding water after the sulfonation reaction, and recovering the reaction solvent by distillation.

The alkyl biphenyl used as a raw material in the present invention has a monoalkyl group having 10 to 20 carbon atoms. Such alkylbiphenyl is obtained by reacting biphenyl with a monoolefin having 10 to 20 carbon atoms in the presence of an alkylation catalyst. The monoolefin used in this reaction has 1 carbon number
0 to 20 linear α-olefins, linear internal olefins,
It is a branched olefin, and the branched olefin is obtained by a low polymerization reaction of propylene and/or butene.

As an alkylation catalyst, AABr= + A7! (J
3GaCIl z r FeCA s 1SbCj2
s + ZrCl2a, SnCl aBCj2:
+, BF3, HF, HtSOa, etc., but these are the most common because of their advantages such as good HF reaction selectivity and ability to suppress the production of by-products.

The sulfonation reaction is carried out in the presence of an aliphatic halogenated hydrocarbon solvent having 1 to 2 carbon atoms.

Examples of such halogenated hydrocarbons include methylene dichloride, carbon tetrachloride, 1,1-dichloroethane, 1.2
-dichloroethane, chloroform, tetrachloroethylene, 1.1,2,2. -Tetrachloroethane.

Examples include ethylene bromide, but in particular 1 which is inert to sulfonating agents and has a boiling point suitable for distillation recovery.
, 2-dichloroethane and/or tetrachloroethylene are preferred.

The appropriate amount of the aliphatic halogenated hydrocarbon to be used is 1 to 20 parts by weight per 1 part by weight of the raw material alkyl biphenyl.

If the amount is less than this, the viscosity increases during the sulfonation reaction, making it impossible to stir sufficiently.

If the amount is larger than this, a reaction apparatus with a large capacity is required, and a large amount of time and energy are required to recover the solvent after the reaction. In particular, it is preferable to use 2 to 1 part by weight.

The sulfonation reaction temperature is 30°C or lower. In particular, the temperature is preferably 10°C or lower. When the reaction temperature is high, the sulfonation reaction is rapid and a high disulfonation rate can be obtained, but deterioration of the disulfonate hue is unavoidable.

Sulfuric anhydride is used as the sulfonating agent. Generally, as a sulfonating agent, in addition to sulfuric anhydride, complexes of sulfuric anhydride and various inorganic or organic compounds, such as chlorosulfonic acid 1 complex with oleum and dioxane, are known.
In these complexes, the disulfonation reaction of alkylbiphenyl does not proceed sufficiently.

Sulfuric anhydride can be supplied in liquid form, gaseous form, or diluted with an inert gas such as nitrogen, air, or argon, but a method in which it is diluted with an inert gas and bubbled into the liquid is particularly preferred. For dilution with inert gas, the concentration of anhydrous sulfuric acid gas is 5 to 1
It is preferable to perform this so that the voltage becomes 0VOLχ.

The amount of sulfuric anhydride supplied is preferably in the range of 1.8 to 2.5 mol, particularly 2.0 to 2.3 mol, per 1 mol of raw material alkyl biphenyl. If the molar ratio of sulfuric anhydride is small, the disulfonation rate will be low, and if the molar ratio is large, the color of the alkyl biphenyl disulfonate will be large and the amount of sulfate by-produced will also increase.

The reaction solution at the initial stage of the sulfonation reaction is a transparent homogeneous phase;
After the reaction is completed, an emulsion-like phase containing disulfonic acid as a main component is precipitated in the reaction solution, and the whole becomes an emulsion-like state, but 20 hours or more of standing time is required for phase separation.

Adding water will shorten the phase separation time, but since the solvent and disulfonic acid are mutually dissolved in both phases, it is better to recover the solvent by distillation without phase separation.

When the sulfonation reaction is directly moved to the distillation recovery process of the aliphatic halogenated hydrocarbon, which is the reaction solvent, the hue of the product deteriorates extremely, but by adding water before proceeding to distillation, the hue during distillation can be improved. The tendency can be reduced.

The effect of water addition is not certain, but it is thought to dilute the sulfuric anhydride that still exists after the sulfonation reaction is complete, or to hydrolyze the sulfonic acid anhydride, which is a reaction by-product, to reduce hue deterioration in subsequent steps. It will be done. The amount of water added is 0.01 to 1 part by weight of alkyl biphenyl used in the reaction.
Part by weight, preferably 0.05 to 0.2 part by weight. If the amount of water added is large, not only will the concentration be lower than necessary when an alkyl biphenyl disulfonate is obtained as an aqueous solution, but it will also tend to foam during the distillation recovery of the aliphatic halogenated hydrocarbon.

Since heat is generated when water is added, it is preferable to stir the mixture and maintain the temperature at 30'C or below.

The distillative recovery of aliphatic hydrocarbons is performed at low temperatures, preferably at a temperature of 4.
Perform at 0°C or below. For this purpose, a depressurization operation is taken. Most of the fractions are distilled at 100 to 200 Torr, but the pressure is further reduced just before the end of the distillation to completely remove the solvent.

The obtained sulfonic acid is dissolved in an alkaline aqueous solution, for example, 25-
Neutralize to pH 7 to 8 using tχNaOH water to obtain alkyl biphenyl disulfonate.

〔Example〕

This will be explained in detail below using experimental examples.

Example 1 60.4 g of alkylbiphenyl, which is a mixture of alkyl groups with carbon numbers of 11 and 12 and has an average molecular weight of 317, and 600 g of 1.2 dichloromethane were placed in a glass 12 flask.
Cooled to ℃.

While stirring, anhydrous sulfuric acid gas diluted to 7 VOLX with nitrogen gas was blown into the liquid. Sulfuric anhydride was supplied in an amount equivalent to 2.3 times the mole of the alkylbiphenyl used, but sufficient stirring was achieved until the end. No unreacted sulfuric anhydride gas was released into the waste gas.

After the sulfonation reaction was completed, 8 g of water was added while stirring while keeping the temperature below 30°C.

The reaction product liquid was distilled under reduced pressure using a rotary evaporator to remove and recover 1,2-dichloroethane. At this time, the temperature of the hot water in the rotary evaporator was maintained at 40° C. or lower. - The obtained sulfonic acid was neutralized to pH 7-8 using 25 wt χ Na0t (water).

A small amount of the sodium sulfonate aqueous solution was collected and measured using an Iatroscan analyzer (Model TH-10, manufactured by Nihon Yatron Co., Ltd.) to determine the disulfonate concentration (disulfonate relative to the total amount of disulfonate and monosulfonate in the product). The ratio of acid salt (hereinafter the same) was measured and found to be 88wtχ.

Sulfonate hue (optical path length of an aqueous solution prepared with a total amount of disulfonate and monosulfonate of 5 wt$, 10 fl,
1000 times the absorbance of light with a wavelength of 420 nm; the same applies hereinafter)
was 420.

Example 2 The same procedure as in Example 1 was carried out except that 1,2 dichloroethane was replaced with nitetrachloroethylene as the reaction solvent.

The disulfonate concentration was 81 wtχ, and the sulfonate hue was 345.

Comparative Example 1 300 g of the alkyl biphenyl used in Example 1 was placed in the glass flask used in Example 1, and cooled to 7°C. While stirring with a stirring blade, anhydrous sulfuric acid gas diluted to 7VOLχ with nitrogen gas was blown into the liquid. From the time when sulfuric anhydride equivalent to 1.2 times the mole of the alkyl biphenyl used was supplied, unused gas was found in the waste gas. The reaction mixture began to contain sulfuric anhydride gas and white smoke began to be generated. At around 1.4 moles, the viscosity of the reaction solution became extremely high, and finally stirring became impossible. A small amount of this reaction solution was sampled and the disulfonic acid concentration was measured and found to be 13imt6A.

Comparative Example 2 60.4 g and n of the alkyl biphenyl used in Comparative Example 1
- 356 g of hexane was placed in the flask used in Example 1 and cooled to 7°C. 7 VOLχ with nitrogen gas while stirring
Anhydrous sulfuric acid gas diluted to 100% was blown into the liquid. Sulfuric anhydride was supplied in an amount equivalent to 2.2 times the mole of alkylbiphenyl used, but stirring was possible until the end. When the amount exceeded 2.0 times the molar amount, the waste gas began to produce a little white smoke.

Post-treatment after the completion of the sulfonation reaction was carried out in the same manner as in Example 1.

When the sulfonic acid sodium salt aqueous solution was analyzed in the same manner as in Example 1, the disulfonate concentration was 57-tz.

Sulfonate hue was 1010.

Example 3. Comparative Examples 3 to 7 The results obtained by changing the amount of solvent used, sulfuric anhydride/alkylbiphenyl molar ratio, reaction temperature, and post-treatment method are shown in the table.

Claims (1)

[Claims] In a method for producing an alkyl biphenyl disulfonate by sulfonating an alkyl biphenyl with anhydrous sulfuric acid, an alkyl biphenyl having a monoalkyl group having 10 to 20 carbon atoms is added at 1 to 2 parts by weight per 1 part by weight of the alkyl biphenyl.
Sulfonation reaction using 0 parts by weight of an aliphatic halogenated hydrocarbon solvent having 1 to 2 carbon atoms at a reaction temperature of 30°C or less and a molar ratio of sulfuric anhydride to alkylbiphenyl in the range of 1.8 to 2.5. A method for producing an alkyl biphenyl disulfonate, which comprises carrying out the sulfonation reaction, adding water, and recovering the solvent by distillation.