JP2008056644A - Water-treating agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an environmental load reduction type water-treating agent which comprises an isothiazolone compound and a nitroalcohol compound and can prevent the decomposition of the isothiazolone compound and stably exhibit high sterilization power even with a small amount of an organic solvent. <P>SOLUTION: This water-treating agent is characterized by comprising an isothiazolone compound, a nitroalcohol compound, and, if necessary, furthermore a triazole compound, and being adjusted to a pH of ≤1.5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a water treatment agent excellent in sterilizing power and stability.

  A water treatment agent containing an isothiazolone compound excellent in sterilizing power, in particular, a water treatment agent containing an isothiazolone compound and a nitroalcohol to further improve the sterilizing power is known (for example, Patent Document 1). ). Such a water treatment agent containing an isothiazolone compound and a nitroalcohol usually has a large amount for stabilizing the contents (particularly for stabilizing the nitroalcohol and suppressing the decomposition of the isothiazolone compound). Organic solvents (organic solvents other than nitroalcohols) are required (for example, Patent Document 2, Patent Document 3, and Patent Document 4). Further, when a water treatment agent is used in a cooling water system or the like, azoles (for example, triazoles) are often contained in order to further improve the anticorrosion of copper and the stabilization of isothiazolone. From this point of view, it is necessary to add a large amount of an organic solvent.

When a water treatment agent contains a large amount of an organic solvent, there is a problem in that the organic solvent becomes nutrients after the sterilization component of the water treatment agent is deactivated, and promotes the growth of microorganisms. . Also, if the water treatment agent contains a large amount of organic solvent, there may be a risk of violating wastewater regulations (chemical oxygen demand (COD _Mn ): 160 mgO / L or less) when the treated water is discharged with the treatment agent added. is there. Furthermore, when the water treatment agent contains a large amount of an organic solvent, there is a problem that foaming of water to which the treatment agent is added may be promoted. Further, Patent Document 4 describes that aminocarboxylic acid is also added, but aminocarboxylic acid has a problem that it can be a nutrient for bacteria and leads to high costs.
Japanese Patent Publication No. 60-21564 Japanese Examined Patent Publication No. 6-94403 Japanese Patent No. 2967525 JP 2000-351704 A

  Accordingly, an object of the present invention is to provide a water treatment agent containing an isothiazolone compound and a nitroalcohol, whether it is a small amount of an organic solvent, desirably in a substantially organic solvent-free state, An object of the present invention is to provide an environmental load-reducing water treatment agent that can suppress the decomposition of nitroalcohols and azoles and can stably exhibit high bactericidal activity.

  In order to solve the above problems, a water treatment agent according to the present invention comprises an isothiazolone compound represented by the general formula [1] in the following chemical formula 1 and a nitroalcohol represented by the general formula [2]. The pH is adjusted to 1.5 or less.

In the above formula, R ¹ is hydrogen, an alkyl group, an alkenyl group, an alkynyl group or an aralkyl group, and R ² and R ³ are hydrogen or halogen, or a benzene ring together with carbons at the 4-position and 5-position of the isothiazolone compound. R ⁴ is hydrogen, halogen, an alkyl group having 1 to 5 carbon atoms or a hydroxyalkyl group having 1 to 5 carbon atoms, and R ⁵ is hydrogen or an alkyl group having 1 to 5 carbon atoms. , R ⁶ is halogen.

  Further, the present invention contains an isothiazolone compound represented by the general formula [1], a nitro alcohol represented by the general formula [2], and a triazole represented by the general formula [3] in the chemical formula 2 below. The pH of the water treatment agent is adjusted to 1.5 or less.

In the above formula, R ¹ is hydrogen, an alkyl group, an alkenyl group, an alkynyl group or an aralkyl group, and R ² and R ³ are hydrogen or halogen, or a benzene ring together with carbons at the 4-position and 5-position of the isothiazolone compound. R ⁴ is hydrogen, halogen, an alkyl group having 1 to 5 carbon atoms or a hydroxyalkyl group having 1 to 5 carbon atoms, and R ⁵ is hydrogen or an alkyl group having 1 to 5 carbon atoms. , R ⁶ is halogen, R ⁷ is hydrogen, an alkyl group, or a phenyl group, and R ⁸ and R ⁹ are hydrogen, an alkyl group, a phenyl group, or an oxo group. In addition, the double bond-like display by the solid line and the broken line in the above formula [3] represents either a double bond or a single bond.

  Such a water treatment agent according to the present invention may be in a form containing two or more nitroalcohols. For example, in addition to the nitroalcohols added to stabilize the isothiazolone compound, a form containing a relatively strong antibacterial nitroalcohol compound such as 2,2-dibromo-nitro-1-ethanol (DBNE) is used. be able to. It is known that the combined use of isothiazolone and DBNE provides a synergistic effect on the prevention of microbial generation and slime formation compared to the case where each is used alone, but these water treatment agents are not necessarily preserved. The stability is not sufficient, and when stored for a long period of time, the isothiazolone compound decomposes or the dispersion state of DBNE deteriorates to cause turbidity, and the antibacterial activity decreases with it. Therefore, in order to improve the storage stability, it is usually necessary to contain an organic solvent other than nitroalcohols, but even in that case, the water treatment agent according to the present invention uses an organic solvent other than nitroalcohols. The amount of solvent can be kept small. At this time, in addition to DBNE, storage stability can be further improved by adopting a form containing nitroalcohols having a high stabilizing effect of the isothiazolone compound.

  It is also known to improve the stability of isothiazolone compounds in ordinary glycol solvents and aqueous solvents by using azoles such as triazoles in combination with nitro alcohols. However, since azoles such as triazoles are difficult to dissolve in water and easily precipitate, it is usually necessary to contain an organic solvent other than nitroalcohols. Even in this case, the water treatment agent according to the present invention Then, the amount of organic solvents other than nitroalcohols can be suppressed to a small amount.

  Moreover, in the water treatment agent which concerns on this invention, it is preferable that COD of water treatment agent itself is 60 (gO / L) or less. The total amount of organic solvents other than nitroalcohols is preferably 1% or less. By adjusting the pH to 1.5 or less, even if the total amount of the organic solvent is reduced to 1% or less, it is possible to stabilize the content component, particularly the component exhibiting bactericidal activity, and the amount of the organic solvent is small. Thus, even after sterilizing power is deactivated, it is possible to reduce the nutrient sources for growing microorganisms. By suppressing the amount of the organic solvent to a small amount, there is less possibility of conflict with the drainage regulation value, and the foaming promotion phenomenon can be suppressed.

  Further, the water treatment agent according to the present invention can further contain a carboxylic acid polymer. This carboxylic acid-based polymer functions as, for example, a dispersant, and when the water treatment agent according to the present invention is used in a cooling water system or the like, it can be expected to prevent the adhesion of scale and the anticorrosion effect.

  Furthermore, the water treatment agent according to the present invention may further contain a lithium salt. This lithium salt can be used, for example, as a tracer substance for confirming the concentration.

Thus, according to the water treatment agent according to the present invention, by mixing the isothiazolone compound, nitroalcohols, and other substances, and adjusting the pH to 1.5 or less, the content of organic solvents other than nitroalcohols can be reduced. Even if the content is reduced to less than 1%, the content components can be stabilized, and excellent sterilizing power can be stably expressed. By reducing the organic solvent content, the COD _Mn of the water treatment agent itself can be easily reduced to 60 (gO / L) or less, thereby suppressing the growth of microorganisms and improving the bactericidal power comprehensively. it can. In addition, by reducing the organic solvent content, it is possible to reduce the risk of conflict with wastewater regulation values (chemical oxygen demand of 160 mgO / L or less), and to suppress foaming of water with water treatment agents added. it can.

Below, this invention is demonstrated in detail centering on an Example.
The water treatment agent according to the present invention comprises an isothiazolone compound represented by the above general formula [1] and a nitroalcohol represented by the above general formula [2], and has a pH of 1.5. The following are adjusted. Alternatively, the water treatment agent according to the present invention is represented by the isothiazolone compound represented by the general formula [1], the nitroalcohol represented by the general formula [2], and the general formula [3]. In which the pH is adjusted to 1.5 or lower. Further, the water treatment agent according to the present invention may contain a carboxylic acid polymer or / and a lithium salt.

  Examples of the isothiazolone compound contained include 2-methyl-4-isothiazolin-3-one, 2-ethyl-4-isothiazolin-3-one, 2-octyl-4-isothiazolin-3-one, and 5-chloro-2. -Methyl-4-isothiazolin-3-one, 5-chloro-2-octyl-4-isothiazolin-3-one, 4,5-dichloro-2-methyl-4-isothiazolin-3-one, 4,5-dichloro -2-octyl-4-isothiazolin-3-one, 1,2-benzisothiazolin-3-one, and the like. The content of the isothiazolone compound is preferably 0.1 to 10% by weight, and more preferably 0.5 to 5% by weight.

  Examples of the nitroalcohols contained include 2-bromo-2-nitropropane-1,3-diol, 2-bromo-2-nitrobutane-1,3-diol, and 3-bromo-3-nitropentane- 2,4-diol, 2,2-dibromo-2-nitro-1-ethanol, 2-nitro-1,3-propanediol, tris (hydroxymethyl) nitromethane, 2-bromo-2-nitro-1,3- Diacetyloxypropane, 3,3-dibromo-3-nitro-2-propanol, 2-chloro-2-nitroethanol, 2-chloro-2-nitro-1,3-propanediol, 3-chloro-3-nitro- 2-propanol etc. are mentioned. These can be used in combination of two or more as required. The content of the nitroalcohol is preferably 0.1 to 30% by weight, more preferably 0.3 to 10% by weight, based on the isothiazolone compound.

  Examples of the triazoles to be contained include 1,2,4-triazole, 1-methyl-1,2,4-triazole, 3-methyl-1,2,4-triazole, and 3,5-dimethyl-1 2,4-triazole, 3,5-diethyl-1,2,4-triazole, 1-phenyl-1,2,4-triazole, 3-phenyl-1,2,4-triazole, 1,5-diphenyl -1,2,4-triazole, 1,3-diphenyl-1,2,4-triazole, 3,5-diphenyl-1,2,4-triazole, 1,2,4-triazol-3-one, 5, -Methyl-1,2,4-triazol-3-one, 3-methyl-1,2,4-triazol-5-one, 1-phenyl-1,2,4-triazol-3-one, 5-phenyl -1,2,4-triazol-3-one, 1-phenyl-1,2,4-triazol-5-one, urazole, 1-phenylurazole, 4-phenylurazo Benzotriazole, 1-methylbenzotriazole, 4-methylbenzotriazole, 5-methylbenzotriazole, 5,6-methylbenzotriazole, 2-phenylbenzotriazole, 1-oxybenzotriazole, 2- (3-t-butyl -5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-di-t-amyl-2-hydroxyphenyl) Benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2 -(2'-hydroxy-5-octylphenyl) benzotriazole, 2- (2-hydroxy- 4'-octoxyphenyl) benzotriazole, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-butylphenyl) benzotriazole, 2- (2'- Hydroxy-3-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3,5-t-aminophenyl) benzotriazole, 2- (2'-hydroxy-3 ' , 5'-di-t-butyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (Α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 1-naphthylbenzotriazole, 5-chlorobenzotriazole, 5-bromobenzotriazole Lumpur, 5-nitro-benzotriazole, 4,5,6,7-tetrahydrobenzo-triazole, and the like. The content of triazoles is preferably 0.1 to 10% by weight, and more preferably 0.3 to 5% by weight.

In the present invention, in order to adjust the pH to 1.5 or less, for example, an inorganic acid such as sulfuric acid, hydrochloric acid or nitric acid or an organic acid such as formic acid, acetic acid, oxalic acid or citric acid can be used. In order to suppress COD _Mn of the agent, it is preferable to use an inorganic acid. In some cases, sodium hydroxide may be added to adjust the pH.

  In the present invention, for example, polyacrylic acid or the like can be used as the carboxylic acid polymer to be added as necessary, and lithium chloride or the like can be used as the lithium salt.

Example 1, Comparative Examples 1 and 2
With the goal of setting the COD of the water treatment agent itself to 60 (gO / L) or less, “Caisson WT” (containing about 10% of 5-chloro-2-methyl-4-isothiazolin-3-one as an isothiazolone compound, 2-methyl-4-isothiazolin-3-one), 2,2-dibromo-nitro-1-ethanol (DBNE) is used as the nitroalcohol, and polyacrylic acid (PAA) is used as the carboxylic acid polymer. ) Was added to prepare a water treatment agent in the amount shown in Table 1. The pH was adjusted using sulfuric acid (98% concentration), the COD of the water treatment agent itself was measured, and the precipitated state and turbid state after storage at 50 ° C. for 5 days were visually determined. The evaluation of precipitation is mainly an evaluation for confirming the effect of triazoles by the pH reduction adjustment in the present invention, and the evaluation of turbidity is an evaluation mainly for confirming the effect of DBNE by the pH reduction adjustment in the present invention. It is. Furthermore, the effective component residual ratio (%) of the component exhibiting bactericidal activity was evaluated by DBNE and 5-chloro-2-methyl-4-isothiazolin-3-one (CMI) which is the main component of Caisson WT. The results are shown in Table 1.

  As shown in Table 1, in Example 1, as compared with Comparative Examples 1 and 2, a small amount of organic solvent was suppressed and an excellent COD of 60 (gO / L) or less was achieved, while both precipitation and turbidity occurred. Thus, a water treatment agent having a high residual ratio of active ingredients was obtained.

Example 2, Comparative Examples 3, 4
In Example 1 and Comparative Examples 1 and 2, benzotriazole (BTA) was further added as a triazole, and the results of evaluation similar to Example 1 and Comparative Examples 1 and 2 are shown in Table 2.

  As shown in Table 2, in Example 2, as compared with Comparative Examples 1 and 2, a small amount of organic solvent was suppressed and an excellent COD of 60 (gO / L) or less was achieved, while both precipitation and turbidity occurred. Thus, a water treatment agent having a high active ingredient residue rate (CMI, DBNE and BTA) was obtained.

Comparative Examples 5 and 6
In order to observe the influence of the pH to be adjusted in more detail, Comparative Examples 5 and 6 were performed, and the results compared with Example 2 are shown in Table 3.

  As shown in Table 3, in Example 2 in which the pH was adjusted to 1.5, 60 (gO / L) or less was superior to Comparative Examples 5 and 6 in which the pH was adjusted to 2.0 and 2.5. A water treatment agent having a high active ingredient residue rate (CMI, DBNE and BTA) was obtained while neither COD nor turbidity occurred while achieving COD.

Comparative Example 7
In order to observe in more detail the effect of the addition of benzotriazole (BTA) as a triazole, Comparative Example 7 was carried out and compared with Example 2 and Comparative Example 3 above. The results are shown in Table 4.

  As shown in Table 4, when benzotriazole (BTA) is added, it can be seen that it is particularly effective to adjust the pH to 1.5.

Test 1
Next, the effect of organic solvents on bacterial growth was investigated.
(Test conditions)
-Sample 1: Pure water was cultured at 30 ° C.
Sample 2: 30 ppm of an organic solvent (ethylene glycol solvent) was added to pure water and cultured at 30 ° C. As Table 5 shows the time-dependent change in the number of bacteria as a test result and the COD (mgO / L) of the specimen, it was confirmed that the growth of the bacteria was promoted by the presence of the ethylene glycol solvent. Therefore, it is desirable that the organic solvent be suppressed to a small amount as much as possible.

Test 2
The difference in bactericidal power between water treatment agents containing organic solvents and water treatment agents not containing them was investigated. (Test conditions)
Bacteria are cultured in advance, and water containing about 10 6 bacteria is prepared. To this, 200 ppm of the water treatment agent of Example 1 and Comparative Example 2 is added and cultured at 30 ° C. Thus, the number of each bacteria was measured. As shown in Table 6 with time, the number of bacteria as a test result shows that the water treatment agent according to the present invention stably exhibits sterilizing power over time. In Comparative Example 2, the number of bacteria once decreased is thought to be due to the fact that the water treatment agent acted as a bactericidal agent. After that, when the bactericidal component was deactivated, the number of bacteria increased and the number of bacteria increased. It is thought that

  The water treatment agent according to the present invention can be applied to the entire water treatment field, and is particularly suitable for use in a cooling water system.

Claims (7)

A water treatment agent comprising an isothiazolone compound represented by the general formula [1] and a nitroalcohol represented by the general formula [2], wherein the pH is adjusted to 1.5 or less.

(In the above formula, R ¹ is hydrogen, an alkyl group, an alkenyl group, an alkynyl group or an aralkyl group, and R ² and R ³ are benzene together with hydrogen or halogen, or carbons at the 4-position and 5-position of the isothiazolone compound. R ⁴ is hydrogen, halogen, an alkyl group having 1 to 5 carbon atoms or a hydroxyalkyl group having 1 to 5 carbon atoms, and R ⁵ is hydrogen or an alkyl group having 1 to 5 carbon atoms. And R ⁶ is halogen.) It contains an isothiazolone compound represented by the general formula [1], a nitroalcohol represented by the general formula [2] and a triazole represented by the general formula [3], and the pH is adjusted to 1.5 or less. Water treatment agent characterized by being made.

(In the above formula, R ¹ is hydrogen, an alkyl group, an alkenyl group, an alkynyl group or an aralkyl group, and R ² and R ³ are benzene together with hydrogen or halogen, or carbons at the 4-position and 5-position of the isothiazolone compound. R ⁴ is hydrogen, halogen, an alkyl group having 1 to 5 carbon atoms or a hydroxyalkyl group having 1 to 5 carbon atoms, and R ⁵ is hydrogen or an alkyl group having 1 to 5 carbon atoms. And R ⁶ is halogen, R ⁷ is hydrogen, an alkyl group, or a phenyl group, and R ⁸ and R ⁹ are hydrogen, an alkyl group, a phenyl group, or an oxo group.)   The water treatment agent according to claim 1 or 2, wherein two or more kinds of nitroalcohols are contained. The water treatment agent according to any one of claims 1 to 3, wherein the chemical oxygen demand COD _{Mn of the} water treatment agent itself is 60 (gO / L) or less.   The water treatment agent according to any one of claims 1 to 4, wherein the total amount of organic solvents other than nitroalcohols is 1% or less.   Furthermore, the water treatment agent in any one of Claims 1-5 formed by containing a carboxylic acid type polymer.   Furthermore, the water treatment agent according to any one of claims 1 to 6, comprising a lithium salt.