JP2727124B2 - Sulfonation of vinylphenol polymer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for sulfonating a vinylphenol-based polymer. More specifically, in order to produce a sulfonated product of a vinylphenol-based polymer, that is, a vinylphenol-based polymer whose nucleus is substituted by a sulfone group, with high efficiency and high purity, and further with a high sulfone group introduction rate as necessary. The present invention relates to a method for sulfonating a vinyl phenol polymer.

(Prior Art) Conventionally, Japanese Patent Application Laid-Open No. 49-66580 or
As disclosed in JP-A-24444, a vinylphenol-based polymer is dissolved in an organic solvent such as paradioxane or acetic acid to produce a sulfonated product of a vinylphenol-based polymer, and concentrated sulfuric acid and sulfuric anhydride are used. A method for sulfonating with a sulfonating agent such as chlorosulfonic acid is known.

Sulfonated products of vinylphenol-based polymers are useful in various fields such as surfactants, polymer flocculants, ion exchangers, conductive agents, chelating agents, and polymer catalysts. In any application, it is needless to say that high purity without impurities is desired, and it is desired that the introduction ratio of the sulfone group is high depending on the application.

However, in the conventionally proposed method, in order to obtain a sulfonated product having a desired sulfone group introduction ratio, it is necessary to use a substantial excess of the sulfonating agent, and therefore, a sulfate or the like caused by the excess sulfonating agent is required. There is a problem that the generation amount of impurities is large.

(Problems to be Solved by the Invention) An object of the present invention is to improve the above-mentioned problems of the conventional method and suppress the formation of impurities such as sulfates by converting a vinylphenol-based polymer sulfonate having a desired sulfone group introduction rate into a sulfonate. Accordingly, it is an object of the present invention to provide a method for sulfonating a vinylphenol-based polymer which can be efficiently produced with high purity.

(Means for Solving the Problems) The present inventors have conducted intensive studies to develop the above-mentioned sulfonation method of the present invention, and found that a vinylphenol-based polymer was dissolved in an organic solvent to form a solution, and the solution was dried. In the sulfonation with sulfuric acid, the presence of a certain amount of chlorinated aliphatic hydrocarbons in the reaction system at a certain room temperature is compared to the case where a certain amount of chlorinated aliphatic hydrocarbons in liquid at this room temperature is not present. , The sulfonation reaction was promoted, and as a result, the following was recognized.

(1) In order to obtain a sulfonated product having a predetermined sulfone group introduction rate, the amount of sulfuric anhydride used can be reduced. Therefore, the amount of unreacted sulfuric anhydride in the reaction product can be reduced, and eventually the desired sulfonated product can be obtained. The ability to reduce impurities such as sulfates contained therein.

(2) When the reaction conditions are constant, the sulfone group introduction rate can be improved.

(3) As a secondary effect, the clogging of the sulfuric anhydride introduction nozzle can be prevented. That is, generally, sulfuric anhydride is introduced into a reaction solution (a solution of a vinylphenol-based polymer in an organic solvent) from an introduction nozzle, but when there is no chlorinated aliphatic hydrocarbon which is liquid at room temperature, the introduction nozzle is dehydrated. In many cases, it is difficult to introduce sulfuric anhydride by being blocked by a white substance considered to be a complex formed by sulfuric acid and an organic solvent.However, when a chlorinated aliphatic hydrocarbon that is liquid at room temperature is present, the introduction nozzle is blocked. Can be prevented.

Therefore, the gist of the present invention is that when a vinylphenol polymer is dissolved in an organic solvent to form a solution and sulfonated with sulfuric anhydride, the chlorinated aliphatic carbonized at room temperature and uniformly mixed with the organic solvent is used. Hydrogen is present in the reaction system in an amount of 0.01 to 1.2 parts by weight with respect to 1 part by weight of the organic solvent in a sulfonation method of a vinylphenol polymer.

Examples of the vinylphenol-based polymer used as a starting material in the present invention include a homopolymer of vinylphenol or a copolymer of vinylphenol and another comonomer,
Examples of the comonomer in the case of the copolymer include styrene, parachlorostyrene, paramethoxystyrene, phenylmaleimide, acrylonitrile, acrylamide, diethyl maleate, dibutyl maleate, methyl methacrylate, vinylimidazole, methyl vinyl ketone, and the like. In the case of a copolymer, the proportion of vinylphenol units is preferably 5 mol% or more (comonomer units are 95 mol% or less). These vinylphenol-based polymers may be those produced by any method without depending on the production history, and those having a weight average molecular weight (Mw) in the range of 240 to 100,000 are appropriate. 1,000
Those having a range of up to 100,000 are preferred.

Examples of the organic solvent used in the present invention include paradioxane, acetic acid, triethyl phosphate, trimethyl phosphate, and the like. The amount of these organic solvents used is usually 2 parts by weight per 1 part by weight of the vinylphenol polymer.
A suitable range of the amount is from 20 to 20 parts by weight, preferably from 4 to 10 parts by weight.

Sulfuric anhydride is used as the sulfonating agent. There are three types of sulfuric anhydride, alpha, beta and gamma, and any of them can be used, but the gamma type which is liquid at room temperature is preferably used. The amount of the sulfuric anhydride to be used is selected according to the desired sulfone group introduction rate of the target vinylphenol polymer sulfonate. The desired sulfone group introduction rate, that is, the number of sulfone groups per phenol nucleus. ,
The range is 1.25 times the theoretical amount or less, preferably 1.02 to 1.10 times the theoretical amount. If the amount exceeds 1.25 times the theoretical amount, the residual amount of unreacted sulfuric anhydride in the reaction product increases, and as a result, when the reaction product is neutralized with an aqueous NaOH solution, the Na ₂ SO ₄ content of the target sulfonated product Increase.

In general, a vinylphenol-based polymer sulfonated product is desired to have a sulfone group introduction rate of 0.2 to 2.0 sulfone groups per phenol nucleus from the viewpoint of its properties and applications.
According to the present invention, a sulfonated product having such a sulfone group introduction ratio can be efficiently obtained with high purity by using the above-mentioned amount of sulfuric anhydride.

In the present invention, as the chlorinated aliphatic hydrocarbon which is present in the reaction system and which is liquid at ordinary temperature, a chlorinated aliphatic hydrocarbon which is uniformly mixed with the organic solvent as described above and which is liquid at ordinary temperature is used. Examples include 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, carbon tetrachloride and the like. Among them, 1,2-dichloroethane is preferably used because it has high stability against sulfuric anhydride and is hardly consumed by being sulfonated during the sulfonation reaction. The amount of the chlorinated aliphatic hydrocarbon which is liquid at room temperature is in the range of 0.01 to 1.2 parts by weight, preferably 0.2 to 0.8 parts by weight, based on 1 part by weight of the organic solvent. If the amount is less than 0.01 part by weight per 1 part by weight of the organic solvent, the desired effect of promoting the sulfonation reaction cannot be obtained. Conversely, if the amount used exceeds 1.2 parts by weight with respect to 1 part by weight of the organic solvent, the desired effect of promoting the sulfonation reaction cannot be obtained.

In carrying out the sulfonation method according to the present invention, any method can be adopted, and the reaction can be carried out in one step or in two steps. For example, when the reaction is performed in one step, a predetermined amount of an organic solvent and a solution obtained by adding a chlorinated aliphatic hydrocarbon liquid at room temperature to a vinylphenol polymer are added with a predetermined amount of sulfuric anhydride, 40 ~
By reacting at a temperature of 100 ° C., preferably 50 to 80 ° C. for 0.5 to 15 hours, sulfonation of the vinylphenol polymer can be carried out. Performing the reaction in one step has the advantage that the reaction operation is simple, but tends to increase the amount of the organic solvent or the chlorinated aliphatic hydrocarbon that is liquid at room temperature and being sulphonated at room temperature and consumed. . For example, when performing the reaction in two stages, first the first
As a step, a solution obtained by adding a predetermined amount of an organic solvent and a chlorinated aliphatic hydrocarbon liquid at room temperature to a vinylphenol-based polymer is added with a predetermined amount of sulfuric anhydride, and 0 to 70 ° C., preferably 20 ° C. The reaction is carried out at a temperature of 5050 ° C. for 0.5 to 5 hours, and then, as a second step, the reaction mixture obtained in the first step is subjected to the first step at a temperature of 40 to 100 ° C., preferably 50 to 80 ° C. The sulfonation of the vinylphenol-based polymer can be carried out by keeping the reaction at a temperature higher than the eye reaction temperature by at least 5 ° C., preferably at least 10 ° C. for 1 to 15 hours to complete the reaction. When the reaction is carried out in two stages, the reaction operation becomes complicated, but there is an advantage that the chlorinated aliphatic hydrocarbon which is liquid at room temperature with the organic solvent can be prevented from being sulfonated and consumed. In any of the above cases, the reaction pressure does not need to be particularly limited, but is usually carried out at normal pressure. Further, sulfuric anhydride can be added to the reaction solution by any method, for example, liquid sulfuric anhydride may be dropped into the reaction solution, or gaseous sulfuric anhydride may be used as it is or diluted with an inert gas. May be blown into the reaction solution.

After completion of the reaction, the desired sulfonated vinylphenol polymer may be separated and obtained from the reaction mixture by any method. For example, a method of distilling an organic solvent and a chlorinated aliphatic hydrocarbon liquid at room temperature by heating from a reaction mixture by heating, or a reaction mixture such as hexane, benzene,
The desired vinylphenol polymer sulfonate can be separated and obtained from the reaction mixture by, for example, a method of precipitating the vinylphenol polymer sulfonate by mixing with a non-solvent such as toluene or ether. The separated and obtained sulfonated product is neutralized with an alkali, if necessary.

When the desired sulfone group introduction ratio of the desired sulfonated vinylphenol polymer is as high as 1.1 to 2.0 sulfone groups per phenol nucleus, the above-described one-step or two-step sulfonation reaction is carried out in two steps. It may be repeated twice to obtain a sulfonated product having a desired sulfone group introduction ratio. That is, for example, first, the first sulfonation is performed using a predetermined amount of sulfuric anhydride targeting a sulfone group introduction rate of 1.0 per phenol nucleus, and then the obtained sulfone group introduction rate of 1.0 per phenol nucleus is obtained. Using the sulfonate as a raw material, the sulfonate introduction ratio of the sulfonate is 0.
By performing the second sulfonation reaction using a predetermined amount of sulfuric anhydride sufficient to increase the number of phenol nuclei by 1 to 1.0, a sulfonated product having a sulfone group introduction rate of 1.1 to 2.0 phenol nuclei can be obtained. good.

(Effect of the Invention) According to the present invention, a sulfonation reaction is promoted more than in the conventional method, and therefore, a sulfonated product of a high-purity vinylphenol polymer having a high sulfone group introduction rate and a small amount of impurities such as sulfates can be efficiently produced. Obtainable.

(Examples) Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 36 g (0.3 mol constitutional unit) of polyparavinylphenol having a weight-average molecular weight (Mw) of 10,600 (measured by GPC using THF as a solvent and calibrating the molecular weight with a polystyrene standard), a thermometer, a dropping funnel with a scale, and reflux The mixture was placed in a 500 ml separable flask equipped with a condenser and a stirrer, and 180 g of paradioxane (weight ratio to the starting polymer: 5) and 90 g of 1,2-dichloroethane (0.5 weight ratio to paradioxane) were added thereto. ° C). While well stirring the solution, 25.5 g (0.318 mol; mol ratio of phenol nucleus to 1.06) of liquid sulfuric anhydride was added dropwise from a calibrated dropping funnel over about 40 minutes. When sulfuric anhydride was added dropwise, the temperature of the raw material solution rose by about 10 ° C. (from about 20 ° C. to 30 ° C.). After the completion of the dropwise addition of sulfuric anhydride, the temperature of the reaction solution was raised, and the mixture was kept at 60 to 65 ° C. for 4 hours with stirring for aging.

After aging, the reaction solution was cooled to room temperature, and 100 g of pure water was added thereto. The solution was neutralized by dropwise addition of a 10% aqueous NaOH solution while cooling. The neutralized solution was filtered to remove insolubles. The obtained filtrate was put into an evaporator, and 50
At 100 ° C. to remove paradioxane, 1,2-dichloroethane and water, and then dried in vacuo at 80 ° C. for 4 hours to obtain a red-brown resin component.
69.8 g were obtained.

When this resin component was analyzed, this resin component had a sulfone group introduction rate of 0.99 sulfone groups per phenol nucleus ( ¹³ C
Calculated from the results of -NMR), the content of Na ₂ SO ₄ 3.1 wt%,
It was a sodium salt of a sulfonated product of polyparavinylphenol having a weight average molecular weight (Mw) of 27,900 (measured by GPC for a water-soluble polymer whose molecular weight was calibrated with water as a solvent and a standard product of sodium polystyrene sulfonate). Further, the generation rate of the insoluble polymer, that is, the ratio of the insoluble content removed by filtering the neutralized solution to the total amount of the insoluble content and the resin content [{insoluble content / (insoluble content + resin content)} × 100] was 0.8% by weight.

Examples 2 to 15 and Comparative Examples 1 to 10 A predetermined amount of a predetermined organic solvent and a predetermined amount of a chlorinated aliphatic hydrocarbon liquid at a predetermined ordinary temperature were added to 36 g (0.3 mol constituent unit) of a predetermined vinylphenol polymer. Was added to form a solution, and a predetermined amount of a predetermined amount of sulfuric anhydride was added to the solution at a predetermined temperature over a predetermined time (first stage), and then kept at a predetermined temperature for a predetermined time to ripen (second stage). Stage). From the reaction solution thus obtained, a resin component was obtained in the same manner as in Example 1. However, in Comparative Examples 1 to 5, 7, 8 and 10, no chlorinated aliphatic hydrocarbon liquid at room temperature was added, and in Example 8 and Comparative Example 5, aging (second stage) was not performed. The experimental conditions and results of these experiments are shown in Tables 1 and 2.

Of the above experimental examples, the molar ratio of sulfuric anhydride to phenol nucleus was
1.06, where the weight ratio of paradioxane to the starting polymer is 5, and the temperature and time of the sulfonation reaction (the first and second stages) are common, in other words, the amount of 1,2-dichloroethane added is The experimental results of Examples 2 to 6 and Comparative Example 1 under the same reaction conditions except for the difference were obtained by taking the sulfone group introduction rate of the obtained sulfonated product on the vertical axis, and plotting 1,2-dichloroethane / para on the horizontal axis. The dioxane weight ratios are shown in FIG. 1 as shown in FIG. Further, of the above experimental examples including Example 1, Examples 1, 4 and 7 and Comparative Examples 2, 3 and 4 in which only the aging time (retention time in the second stage) was different (1 in this comparative example) , 2-Dichloroethane was not used, so the amount of paradioxane was increased by that amount). The ordinate represents the sulfone group introduction rate of the obtained sulfonated product, and the abscissa represents the aging time. FIG. 2 is a diagram showing the state of FIG.
In FIG. 2, a plot (○) connected by a solid line is the result of the example, and a plot (△) connected by a dotted line is the result of the comparative example. From these figures, the effect of adding a fixed amount of chlorinated aliphatic hydrocarbon which is liquid at normal temperature will be more easily understood.

[Brief description of the drawings]

FIG. 1 is a diagram relating to experimental results of Examples 2 to 6 and Comparative Example 1, and FIG. 2 is a diagram relating to experimental results of Examples 1, 4 and 7 and Comparative Examples 2 to 4.

Claims (2)

(57) [Claims] When a vinylphenol polymer is dissolved in an organic solvent to form a solution and sulfonated with sulfuric anhydride, a chlorinated aliphatic hydrocarbon liquid at room temperature and uniformly mixed with the organic solvent is mixed with the organic solvent. 0.01 to 1 part by weight of organic solvent
A method for sulfonating a vinylphenol polymer, wherein the vinylphenol polymer is present in a reaction system in an amount of 1.2 parts by weight. 2. The amount of the chlorinated aliphatic hydrocarbon which is present at room temperature and is present in the reaction system in an amount of 0.2 to 1 part by weight of the organic solvent.
2. The method for sulfonating a vinylphenol-based polymer according to claim 1, wherein the amount is 0.8 parts by weight.