JPH1025256A - Purification of polar organic solvent and apparatus for regenerating cooling liquid containing antifreeze liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To purify an anion-containing polar organic solvent to an extent to exhibit excellent anion-removing effect on a polar organic solvent even at a relatively high temperature while preventing the degradation of the solvent by using a specific anion-exchange resin. SOLUTION: An anion-containing polar organic solvent is purified by using an anion exchange resin having a quaternary ammonium salt group of the formula (A is a 3-8C straight-chain alkylene or a 4-9C alkoxymethylene; R<1> is an (OH-substituted) 1-4C alkyl; R<2> and R<3> are each a 1-4C hydrocarbon group; X<-> is a counter ion coordinated to the ammonium group; the benzene ring may be substituted with an alkyl or a halogen) and a structural unit derived from a crosslinkable monomer containing an unsaturated hydrocarbon group. The anion exchange resin preferably contains the quaternary ammonium group of the formula in an amount accounting for >=90% of the total anion exchange group. The anioncontaining polar organic solvent is e.g. a cooling liquid containing an antifreeze liquid for an internal combustion engine of automobile. This invention also provides an apparatus for the regeneration of the cooling liquid containing antifreeze liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying a polar organic solvent and an apparatus for regenerating an antifreeze-containing cooling liquid. More specifically, the present invention relates to a method of using a specific anion exchange resin even at a relatively high temperature. The present invention relates to the above-mentioned purification method and regenerating apparatus improved so as to achieve an excellent anion removing effect.

[0002]

2. Description of the Related Art For example, in an engine cooling fluid of an automobile,
Alcohol (eg glycols such as ethylene glycol) to ensure the antifreeze and non-boiling properties of the coolant
And corrosion inhibitors such as inorganic salts and organic amines.

By the way, when a car travels for a certain distance,
For example, the generation of acids (acetic acid, glycolic acid, formic acid, etc.) by the decomposition of ethylene glycol and the corrosion of the cooling system metal by chemical or electrochemical processes increase the amount of soluble metal and the suspension of metal oxides. Accumulation occurs and engine coolant degrades.

JP-A-7-108141 and JP-A-7-108141
JP-A-208166 proposes a method using an ion-exchange resin as a method of regenerating used antifreeze (engine coolant), and JP-A-7-34872 discloses processing of an antifreeze for cooling an automobile engine. As an apparatus, an apparatus comprising a pump motor for pumping antifreeze for cooling an automobile engine to an antifreeze processing apparatus, a filter for removing hydroxylated heavy metals and dust, and an ion exchange resin tower for removing ionized substances has been proposed. ing. Such an antifreeze is used not only in an internal combustion engine such as an engine but also in a cooling system of a rectifier such as an engine generator.

[0005] Japanese Patent Application Laid-Open No. 7-208166 discloses, as specific examples of anion exchange resins, commercially available "Amberlite IRA-400" and "Amberlite IRA-400".
68 "(both are trade names). The former is a strongly basic anion exchange resin, and the latter is a weakly basic anion exchange resin.

Incidentally, in a polar organic solvent typified by an antifreeze solution, a certain kind of anion exchange resin deteriorates as shown in a comparative example described later. On the other hand, it is necessary to select an anion exchange resin which is chemically stable.

[0007] Further, the purification of the polar organic solvent is often performed at a relatively high temperature. For example, when a regenerator is arranged in the circulation path of the antifreeze-containing coolant in the internal combustion engine,
The anion exchange resin of the regenerator will come into contact with the antifreeze containing coolant at a relatively high temperature, for example around 80 ° C. Furthermore, antifreeze such as a cooling system for a rectifier has a temperature of about 65 ° C. in summer when the rectifier is arranged outdoors. Therefore, in the purification of polar organic solvents,
It is necessary to select a stable anion exchange resin that can withstand the above high temperatures in a polar organic solvent.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to reduce the deterioration caused by a polar organic solvent, and in particular, to sufficiently solve a polar organic solvent at a relatively high temperature. It is an object of the present invention to provide a method for refining a polar organic solvent and an apparatus for regenerating an antifreeze-containing coolant, which are improved so as to be applicable to the present invention.

[0009]

The present inventors have made various studies to achieve the above object, and as a result, it has been found that an anion exchange resin having a specific structure, which is already known, has excellent stability to polar organic solvents. And completed the present invention.

That is, a first gist of the present invention is to derive from a structural unit having a quaternary ammonium group represented by the general formula (I) and an unsaturated hydrocarbon group-containing crosslinkable monomer according to claim 1. A second object of the present invention is to provide a method for purifying a polar organic solvent, comprising treating an anion-containing polar organic solvent with an anion exchange resin containing a structural unit. An apparatus for regenerating the antifreeze-containing cooling liquid, wherein the apparatus uses the anion exchange resin described above.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
First, the anion exchange resin used in the present invention will be described. The anion exchange resin contains a structural unit having a quaternary ammonium group represented by the general formula (I) and a structural unit derived from an unsaturated hydrocarbon group-containing crosslinkable monomer.

In the general formula (I), A represents 3 to 8 carbon atoms.
Represents a linear alkylene group or an alkoxymethylene group having 4 to 9 carbon atoms, and examples of the linear alkylene group include a propylene group, a butylene group, a pentylene group, and a hexylene group. Examples of the alkoxymethylene group include a butoxymethylene group and a pentoxymethylene group.

In the general formula (I), R ¹ is an alkyl group having 1 to 4 carbon atoms which may be substituted by a hydroxyl group, R ² and R
³ represents an alkyl group having 1 to 4 carbon atoms, and examples of these alkyl groups include a methyl group, an ethyl group, a propylene group, and a butylene group.

[0014] In the general formula (I), X ^- represents a counter ion coordinated to ammonium groups, as a concrete is
Examples thereof include halogen ions such as Cl ⁻ , Br ⁻ and I ⁻ , sulfate ions, and anions such as NO ₃ ⁻ , OH ⁻ and p-toluenesulfonic acid ions. When the anion is divalent like a sulfate ion, one molecule of the anion binds to two molecules of the structural unit represented by the general formula (I). Examples of the alkyl group of the substituent on the benzene ring include a methyl group and an ethyl group.
Chlorine, bromine, iodine and the like.

In the general formula (I), R ² and R ³ are preferably a methyl group, and more preferably, a trimethylammonium base (type-I strong basic resin) or R ^{1 wherein} R ¹ is a methyl group.
Is preferably a dimethylhydroxyethylammonium base having a hydroxyethyl group (type II strong basic resin).

Examples of the unsaturated hydrocarbon group-containing crosslinking monomer include divinylbenzene, trivinylbenzene, divinyltoluene, divinylnaphthalene, divinylxylene,
Examples include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate. Of these, divinylbenzene is preferred.

In the anion exchange resin used in the present invention, the ratio of the quaternary ammonium group represented by the general formula (I) to all anion exchange groups is preferably 90% or more. It is particularly preferred that substantially the entire amount is a quaternary ammonium group represented by the general formula (I).

The anion exchange resin used in the present invention is known, for example, as described in JP-A-7-289921, and some of its uses are described in JP-A-5-49950.
And JP-A-5-49951, JP-A-5-49952, and JP-A-5-57200. However, these publications do not disclose the use of the above-mentioned anion exchange resin for the purification of a polar organic solvent, nor do they describe the stability of the above-mentioned anion exchange resin with respect to a polar organic solvent.

Japanese Patent Publication No. 42542/1990 discloses a resin having a structure similar to the anion exchange resin used in the present invention. This resin, -C _n H _2n -X
(Wherein, X is a chlorine or bromine atom, and n is an integer of 1 to 4), which is obtained by reacting a cross-linked copolymer with a tertiary amine. Disclosed are only those resins wherein the integer n is one.

When the resin having an integer n of 3 or 4 is produced according to the disclosed method, the resin may be-(CH ₂ ) ₃ -X or-
The amount of the anion exchange group derived from the haloalkyl group represented by (CH ₂ ) ₄ —X is very small. The strongly basic anion exchange resin in which the integer n is 1 is greatly deteriorated by the polar organic solvent, and cannot be used for purifying the polar organic solvent.

The reason why the anion exchange resin used in the present invention has high stability to a polar organic solvent is presumed from the above facts as follows. That is, in the structure of the quaternary ammonium salt group represented by the general formula (I), A present as a spacer between the benzene ring and the quaternary nitrogen atom is a straight-chain alkylene group having 3 to 8 carbon atoms or carbon atom. It is presumed that the alkoxymethylene of Formulas 4 to 9 and a relatively long chain may contribute to the suppression of deterioration by the polar organic solvent.

In the anion exchange resin used in the present invention, as described above, 90% or more of all anion exchange groups are preferably quaternary ammonium groups represented by the general formula (I). The reason that the anion exchange resin used in the present invention is stable to polar organic solvents at a relatively high temperature is due to the synergistic action of both the existence of the long spacer A and the high content structure of the quaternary ammonium group. It is presumed that.

Next, the purification method of the present invention will be described. In the purification method of the present invention, representative examples of the polar organic solvent include alcohols such as ethylene glycol, diethylene glycol, polyethylene glycol, glycerin, ethanol, and methanol, ethers such as glyme, and aqueous solutions thereof. As specific examples of the anion-containing polar organic solvent, typically, an antifreeze-containing coolant in an internal combustion engine such as an automobile engine, an antifreeze in a rectifier such as an engine generator and other devices and a machine / apparatus cooling system. And a contained cooling liquid.

[0024] The above-mentioned antifreeze-containing cooling liquid includes chlorine, sulfuric acid,
Contains anions and anionic organic substances such as nitric acid, boron, phosphoric acid, molybdic acid, silica, glycolic acid, formic acid, and acetic acid. In addition, sodium,
Contains ions of potassium, copper, iron, aluminum, lead, zinc, etc.

In the purification method of the present invention, the polar organic solvent containing anions is treated with a specific anion exchange resin which is stable to the polar organic solvent. However, in the purification method of the present invention, it is optional to combine various kinds of conventionally known cation exchange resins, and the combination is usually carried out.

Examples of the cation exchange resin include a strongly acidic cation exchange resin having a sulfonic acid group as a functional group (for example, “Diaion SK-1” (registered trademark) manufactured by Mitsubishi Kasei Co., Ltd.) and a weak cation exchange resin having a carboxylic acid group. Acidic cation exchange resin (for example, "Diaion WK-10" manufactured by Mitsubishi Kasei Corporation)
(Registered trademark)). In addition, a chelate resin (for example, "Diaion CR-10" (registered trademark) manufactured by Mitsubishi Kasei Co., Ltd.) can be used in combination as the anion exchange resin. The combination of the resins may be either a mixed bed type or a double bed type.

In the purification method of the present invention using the above-mentioned anion exchange resin, conditions such as the temperature at which the resin is used and the flow rate of the processing solution are appropriately selected. The working temperature of the resin is usually in the range of −50 ° C. to + 90 ° C. However, in the purification method of the present invention, the deterioration of the resin due to the polar organic solvent is suppressed even at a relatively high temperature by using a specific anion exchange resin. Therefore, 30-100
The effect of the purification method of the present invention is remarkable in purification requiring a resin temperature of 50 ° C, particularly 50 to 90 ° C.

Next, an apparatus for regenerating an antifreeze-containing coolant according to the present invention will be described. The regenerating apparatus of the present invention is similar to the antifreeze processing apparatus described in JP-A-7-34872 described above.
The antifreeze-containing coolant is disposed in a circulation path of the antifreeze-containing coolant in the internal combustion engine, and purifies the antifreeze-containing coolant. The feature of the regenerating apparatus of the present invention resides in that the above-mentioned anion exchange resin is used.

As described above, the anion exchange resin is
Usually, it is used in combination with a cation exchange resin and / or a chelate, and is disposed in a circulation path of the antifreeze-containing cooling liquid according to the type of a resin tower (column), and by appropriately employing a cassette method or the like. As the circulation path of the antifreeze-containing coolant, a flow path between the engine and the radiator is usually selected, but may be a circulation bypass flow path formed for a heater or the like in a vehicle compartment.

[0030]

The present invention will be described in more detail with reference to the following examples. In the following examples, the stability of the anion exchange resin used in the present invention in a polar organic solvent was evaluated, and the effects of the purification method and the regeneration device of the present invention were clarified. In the following description, meq / g represents a milliequivalent per dry resin weight. The exchange capacity of the anion exchange resin was measured according to Diaion Manual (issued by Mitsubishi Chemical Corporation).

Production Example 1 <Synthesis of 4-bromobutylstyrene (1)> A 1000 ml separating funnel type four-necked flask equipped with a nitrogen gas inlet tube, a Dimro cooling tube, a constant-pressure dropping funnel with a branch tube, and a stirring blade. Then, 52.5 g (2.16 g atom) of metallic magnesium and 360 ml of tetrahydrofuran (THF) were added thereto, and the internal temperature was set at 30 ° C. In this flask, 251 g (1.81 mol) of p-chlorostyrene (CS) in THF was added.
350 ml of the solution was added dropwise over 2 hours so that the internal temperature did not rise to 40 ° C. or higher, to obtain a Grignard reagent of CS.

A 2,000 ml four-necked flask having the same structure as described above was connected to the bottom of the flask, and 1,060 g (4.91 mol,
2.71 eq / CS), THF 600 ml, coupling catalyst Li ₂ CuCl ₄ 7.5 g (0.034 mol, 1.
9 mol% / CS) to prepare a solution. Next, the Grignard solution of CS prepared above was dropped into the solution in the flask at room temperature for 1 hour.

After the obtained solution is poured into water, liquid separation is performed.
The aqueous phase was removed. The organic phase was distilled off under reduced pressure, and 1,4-dibromobutane used in a large excess (bp 52 ° C./0.5.
5 mmHg), unreacted CS was distilled off, and finally the desired product, 4-bromobutylstyrene (pale yellow transparent solution, b
130 ° C / 0.2 mmHg).

<Synthesis of Crosslinked 4-Bromobutylstyrene Copolymer (2)> 500 equipped with a nitrogen gas inlet tube and a cooling tube
200 ml of demineralized water and 50 ml of a 2% aqueous polyvinyl alcohol solution were added to a 4 ml four-necked flask, and nitrogen was introduced to remove dissolved oxygen. On the other hand, the 4-
78.0 g (0.326 mol) of bromobutylstyrene,
A monomer solution was prepared by dissolving 3.25 g (0.0200 mol) of divinylbenzene (divinylbenzene content: 80%) and 0.67 g of benzoyl peroxide (BPO) (content: 75%).

The obtained monomer solution was placed in the flask and stirred at 160 rpm to prepare a suspension. After stirring at room temperature for 30 minutes, the mixture was heated to 80 ° C. and stirred for 12 hours to carry out suspension polymerization to obtain a pale yellow transparent spherical polymer. Next, the obtained polymer was taken out and washed with water. Polymerization yield is 95%
And the charged crosslinking degree of the polymer was 6 mol%.

<Amination of 4-bromobutylstyrene cross-linked copolymer> In a 500 ml four-necked flask equipped with a cooling tube, g of the polymer obtained in Synthesis (2) was placed, and 200 ml of 1,4-dioxane was added. And stirred at room temperature. Then
177 g (0.90 mol) of a 30% aqueous solution of trimethylamine was added and reacted at 50 ° C. for 6 hours to obtain an anion exchange resin A. Next, the obtained anion exchange resin A was taken out and washed with water. Substantially all of the anion exchange groups of the anion exchange resin A are quaternary ammonium groups represented by the general formula (I).

In order to convert the counter ion of the anion exchange resin A from a bromide ion to a chloride ion (Cl type), a 4% aqueous solution of 4% sodium chloride with respect to the resin amount was passed. The neutral salt decomposition capacity of the obtained Cl-type anion exchange resin A was 1.24 meq / ml (3.57 meq).
/ G), and the water content was 48.9%.

Production Example 2 In the synthesis (2) in Production Example 1, the amount of divinylbenzene used was 3.03 g (0.0186 mol),
Was operated in the same manner as in Synthesis (2) in Production Example 1 except that the amount of was changed to 0.63 g, and the charged crosslinking degree was 5 mol%.
Was obtained as a pale yellow transparent spherical polymer (4-bromobutylstyrene crosslinked copolymer). The polymerization yield was 94%.

In the amination reaction of Production Example 1, the amount of the aqueous solution of trimethylamine used was 156 g (0.1%).
The same operation as in the amination reaction of Production Example 1 was performed except that the amount was changed to 79 mol). Obtained Cl-type anion exchange resin B
Has a neutral salt decomposition capacity of 1.26 meq / ml (3.66 m
eq / g) and the water content was 51.2%.

Stability evaluation test (1) Weigh 50 ml of Cl-type anion exchange resin B and 500 ml
2N-sodium hydroxide aqueous solution is passed through to form an OH type, and a 60% aqueous solution of ethylene glycol (EG) or 100% EG, which is 10 times the amount of the resin, is passed therethrough, and the resin is turned into E.
Replaced with G solution.

The OH type resin replaced with the EG solution was put into a glass autoclave tube, and a 60% EG aqueous solution or 100% EG in an amount 0.8 times the volume of the OH type resin was added. Then, in order to remove dissolved oxygen in the container, nitrogen gas was passed for 30 minutes while heating at 50 ° C. This autoclave tube was immersed in an oil bath and allowed to stand at 80 ° C. for one month.
Thereafter, the mixture was treated with a 2N aqueous solution of sodium hydroxide (500 ml), and a 4% aqueous solution of sodium chloride (5 times the amount of the resin) was passed through to convert the counter ion X to Cl.

Then, the residual ratio of the alkylene chain A in the resin was determined by the following formula. The symbol A in the calculation formula indicates the neutral salt decomposition capacity (meq / ml), and B indicates the volume (ml) of the Cl-type resin. The results are shown in Table 1. The comparative resin in Table 1 is an anion exchange resin "Diaion S" manufactured by Mitsubishi Chemical Corporation.
A-10 "(registered trademark).

[0043]

## EQU1 ## Residual rate (%) = (A after test) × (B after test) ÷ (A before test) × (B before test) × 100

[0044]

[Table 1]

Stability evaluation test (2) 50 ml of Cl-type anion exchange resin A was weighed and 500 m
of 2N-sodium hydroxide aqueous solution to make OH type, and an alcohol solution (alcohol solution component: 66% by weight of methanol: 2-hydroxy-3-methoxypropane (hereinafter referred to as glycol ether)) (Abbreviation: 32% by weight), and the anion exchange resin A was replaced with an alcohol solution.

The substituted OH type resin was placed in a glass autoclave tube, and an alcohol solution 0.8 times the OH type resin was added. 4 to remove dissolved oxygen in the container
While heating to 0 ° C., nitrogen gas was passed in for 15 minutes. This autoclave tube was immersed in an oil bath and left at 80 ° C. for 2 months. Thereafter, the mixture was treated with 500 ml of a 2N-sodium hydroxide aqueous solution, and a 4% aqueous solution of sodium chloride having a volume 5 times the amount of the resin was passed therethrough to convert a counter ion from OH type to Cl type.

The volume and general performance of the above resin were measured.
Then, the residual ratio of the alkylene chain A in the resin was determined in the same manner as described above. The results are shown in Table 2. The comparative resin in Table 2 is "Diaion SA-10".

[0048]

[Table 2]

As is clear from the results shown in Tables 1 and 2, the anion exchange resin used in the present invention is extremely stable in a polar solvent. Therefore, the purification method of the present invention can be expected to exhibit an excellent purification effect even in a high-temperature polar organic solvent.

[0050]

According to the present invention described above, a polar organic solvent which is less deteriorated by a polar organic solvent and is particularly improved so as to be sufficiently applicable to a polar organic solvent at a relatively high temperature. A purification method and an apparatus for regenerating an antifreeze-containing coolant are provided, and the present invention has great industrial value.

Claims (6)

[Claims] 1. An anion-containing polar organic compound comprising an anion exchange resin containing a structural unit having a quaternary ammonium salt group represented by the following general formula (I) and a structural unit derived from an unsaturated hydrocarbon group-containing crosslinkable monomer. A method for purifying a polar organic solvent, comprising treating a solvent. Embedded image (In the general formula (I), A represents a linear alkylene group having 3 to 8 carbon atoms or an alkoxymethylene group having 4 to 9 carbon atoms, and R ¹ has 1 to 4 carbon atoms which may be substituted with a hydroxyl group. An alkyl group, R ² and R ³ are a hydrocarbon group having 1 to 4 carbon atoms,
X ⁻ represents a counter ion coordinated to an ammonium group, and the benzene ring may be substituted with an alkyl group or a halogen atom. ) 2. Formula (I) for all anion exchange groups
The purification method according to claim 1, wherein the ratio of the quaternary ammonium group represented by is 90% or more. 3. The purification method according to claim 1, wherein the polar organic solvent is an alcohol, an ether, or an aqueous solution thereof. 4. The purification method according to claim 1, wherein the polar organic solvent is an antifreeze-containing cooling liquid. 5. The purification method according to claim 4, wherein the antifreeze-containing coolant is for an internal combustion engine. 6. A regenerating apparatus for an antifreeze-containing coolant disposed in a circulation path of an antifreeze-containing coolant in an internal combustion engine, characterized by using the anion exchange resin according to claim 1 or 2. Playback device.