A method for removing the pungent odor in 1,2-benzisothiazol-3-one

Abstract

The present invention provides a method for removing the pungent odor in 1,2-benzisothiazol-3-one, which relates to the technical field of fine chemicals. The present invention includes the following steps: (1) Alkali dissolution: Add BIT into water and adjust the pH to alkaline with an alkali; (2) Reaction for deodorization: Add a deodorant to the BIT alkaline solution and react for 0.1 to 4 hours; (3) Acidification: Add an acid to the deodorized alkaline solution to adjust the pH to 3 to 7, preferably in the pH range of 4 to 7; BIT precipitates, is filtered, and dried to obtain a odorless BIT product.

Description

Technical Field

[0001] The present invention relates to the field of fine chemical technology, and particularly relates to a method for removing the pungent odor in 1,2-benzisothiazol-3-one. Background Art

[0002] 1,2-Benzisothiazol-3-one (abbreviated as BIT) is a main industrial bactericide, preservative, and anti-enzyme agent. It has outstanding effects in inhibiting the growth of microorganisms such as molds (fungi, bacteria), algae, etc. in organic media, and solves a series of problems such as mildew, fermentation, deterioration, demulsification, and odor caused by the growth of microorganisms. Therefore, developed countries widely use BIT in products such as latex products, water-soluble resins, coatings (latex paints), acrylics, polymers, polyurethane products, photographic developers, papermaking, inks, leather, lubricating oils, etc.

[0003] However, due to the presence of trace impurities in BIT, the BIT product has a pungent odor, which has an adverse impact on the relevant operators during production, transportation, and use. To solve this problem, some manufacturers use chlorobenzene as a reaction solvent, which gives the product a certain aromatic smell to cover up the bad smell of the BIT product, but the residual solvent will still be harmful to the human body.

[0004] The invention patent with the patent number CN114181124A discloses the production process of BIT. After research, it is found that the chlorinated solvent has a strong pungent odor and contains a high concentration of 3-chloro-1,2-benzisothiazole. The generation mechanism of 3-chloro-1,2-benzisothiazole is speculated as follows:

[0005]

[0006] After BIT is generated in the chlorination stage, in the presence of high-concentration hydrogen chloride, BIT reacts with hydrogen chloride to produce BIT hydrochloride, which further reacts with chloride ions to form 3-chloro-1,2-benzisothiazole hydrochloride. After the 3-chloro-1,2-benzisothiazole hydrochloride is dissolved in alkali and acidified, it remains in BIT, forming a characteristic odor. According to the generation mechanism of odor substances, it can be seen that BIT is generated in the chlorination stage, and it is almost inevitable to produce characteristic odor substances in BIT. Moreover, there is currently no research on the removal of odor substances in BIT products at home and abroad. The reasons for the generation of the pungent odor in BIT products and how to remove the pungent odor in BIT products have not been reported in the literature. Summary of the Invention

[0007] In order to solve the technical problems existing in the prior art, the inventor separated and identified the source of the pungent odor in the BIT product, synthesized and separated the impurities presenting the pungent odor, and developed a method capable of effectively eliminating the pungent odor in 1,2-benzisothiazolin-3-one according to the characteristics of the odor substances.

[0008] A method for removing the pungent odor in 1,2-benzisothiazolin-3-one comprises the following steps:

[0009] (1) Add 1,2-benzisothiazolin-3-one into water, adjust the pH value to 8.5 - 11.5 with an alkali to obtain a 1,2-benzisothiazolin-3-one alkali solution;

[0010] (2) Add a deodorant to the 1,2-benzisothiazolin-3-one alkali solution described in step (1), react for 0.1 - 4 hours to obtain a deodorized 1,2-benzisothiazolin-3-one alkali solution;

[0011] (3) Add an acid to the deodorized 1,2-benzisothiazolin-3-one alkali solution described in step (2) to adjust the pH value of the solution within the range of 3 - 7, and odorless 1,2-benzisothiazolin-3-one is obtained.

[0012] Preferably, the alkali described in step (1) is any one of sodium hydroxide and potassium hydroxide.

[0013] Preferably, the pH value described in step (1) is within the range of 9.5 - 10.5.

[0014] Preferably, the temperature of the reaction described in step (1) is 25 - 100 °C.

[0015] Preferably, the deodorant described in step (2) is selected from at least one of urea, ammonia water, and sulfamic acid.

[0016] Preferably, the temperature of the reaction described in step (2) is 25 - 100 °C.

[0017] Preferably, the temperature of the reaction described in step (2) is 50 - 70 °C.

[0018] Preferably, the dosage of the deodorant described in step (2) is 0.01% - 0.5% of the mass of 1,2-benzisothiazolin-3-one.

[0019] Preferably, the dosage of the deodorant described in step (2) is 0.01% - 0.05% of the mass of 1,2-benzisothiazolin-3-one.

[0020] Preferably, the acid described in step (3) is at least one of hydrochloric acid, sulfuric acid, and phosphoric acid.

[0021] Preferably, the acid described in step (3) is hydrochloric acid.

[0022] In the 1,2-benzisothiazol-3-one (BIT) product produced by the method for removing the pungent odor in 1,2-benzisothiazol-3-one provided by the present invention, the content of the pungent odor substance is less than 1 ppm. Further preferably, the content of the pungent odor substance is less than 0.5 ppm, and more preferably, the content of the pungent odor substance is less than 0.1 ppm.

[0023] Compared with the prior art, the present invention has the following beneficial effects: The present invention does not use organic solvents, removes the impurities presenting pungent odor in the BIT product, obtains a odorless BIT product, and improves the quality of the BIT product. Description of the Drawings

[0024] Figure 1 is the gas chromatogram of 3-chloro-1,2-benzisothiazole prepared in Example 1 of the present invention (the peak at 7.310 min is 3-chloro-1,2-benzisothiazole);

[0025] Figure 2 is the mass spectrum of 3-chloro-1,2-benzisothiazole prepared in Example 1 of the present invention (the molecular ion peak is 169.01);

[0026] Figure 3 is the standard mass spectrum of 3-chloro-1,2-benzisothiazole prepared in Example 1 of the present invention;

[0027] Figure 4 is the liquid chromatogram of 3-chloro-1,2-benzisothiazole prepared in Example 1 of the present invention (the peak at 8.590 min is 3-chloro-1,2-benzisothiazole);

[0028] Figure 5 is the external standard liquid chromatogram of BIT before treatment in Example 2 of the present invention (the peak at 8.620 min is 3-chloro-1,2-benzisothiazole; the peak at 3.552 min is the BIT peak);

[0029] Figure 6 is the external standard liquid chromatogram of BIT after treatment in Example 2 of the present invention. Detailed Embodiments

[0030] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described clearly and completely below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope protected by the present invention.

[0031] In the following examples, the test methods or testing methods described, unless otherwise specified, are all conventional methods; the raw materials and auxiliaries, unless otherwise specified, are all obtained from conventional commercial channels or prepared by conventional methods.

[0032] Example 1

[0033] Synthesis of the odor impurity 3-chloro-1,2-benzisothiazole:

[0034] Charge 75.6 g (dry, 0.5 mol) of BIT, 150 g of DMF (2.0 mol) and 100 g of chlorobenzene into the reaction kettle, stir and heat up to 75 °C; after dropping 90 g of thionyl chloride (0.75 mol), continue the reaction for 4 h; after the reaction is completed, add 250 g of water into the reaction kettle, and then slowly add about 200 g of 30% sodium hydroxide solution dropwise to adjust the pH to 5 - 6. Separate the oil layer, and then distill off the solvent under reduced pressure to obtain about 67 g of the product in the kettle (yellow to light yellow wax, yield about 75%; GC: 96.69%; HPLC: 97.48%).

[0035] The gas-phase peak emergence time of the product is about 7.1 min, and the liquid-phase peak emergence time is about 8.5 min.

[0036] The product is formulated into an aqueous solution of 5 ppm for odor comparison with the deodorized BIT product.

[0037] Example 2

[0038] A method for removing the pungent odor in 1,2-benzisothiazolin-3-one, comprising the following steps:

[0039] (1) Take 180 g of 1,2-benzisothiazolin-3-one and place it in the reaction kettle, then add 380 g of water, heat up to 50 °C, and add 30% sodium hydroxide to adjust the pH value to 9, consuming about 133 g of liquid alkali to obtain a 1,2-benzisothiazolin-3-one alkali solution;

[0040] (2) Add 0.2 g of urea to the 1,2-benzisothiazolin-3-one alkali solution described in step (1), and continue to stir and react at 50 °C for 2 hours to obtain a deodorized 1,2-benzisothiazolin-3-one alkali solution;

[0041] (3) Add hydrochloric acid to the deodorized 1,2-benzisothiazolin-3-one alkali solution described in step (2) to adjust the pH value of the solution to 5.5, a large amount of white solid precipitates, filter and dry to obtain odorless 1,2-benzisothiazolin-3-one.

[0042] The content of the odor substance tested by liquid-phase external standard is not detected.

[0043] Example 3

[0044] A method for removing the pungent odor in 1,2 - benzisothiazolin - 3 - one, comprising the following steps:

[0045] (1) Take 190 g of 1,2 - benzisothiazolin - 3 - one and place it in a reaction kettle, then add 380 g of water, heat up to 50 °C, add 42% potassium hydroxide to adjust the pH value to 9, consuming about 133 g of the alkali solution, to obtain a 1,2 - benzisothiazolin - 3 - one alkali solution;

[0046] (2) Add 2 g of ammonia water (ammonia content is 28%) to the 1,2 - benzisothiazolin - 3 - one alkali solution described in step (1), and continue to stir and react at 50 °C for 2 hours to obtain a deodorized 1,2 - benzisothiazolin - 3 - one alkali solution;

[0047] (3) Add hydrochloric acid to the deodorized 1,2 - benzisothiazolin - 3 - one alkali solution described in step (2), adjust the pH value of the solution to 5.5, a large amount of white solid will precipitate, filter and dry to obtain odorless 1,2 - benzisothiazolin - 3 - one.

[0048] The content of the odor substance detected by liquid - phase external standard is not detected.

[0049] Example 4

[0050] A method for removing the pungent odor in 1,2 - benzisothiazolin - 3 - one, comprising the following steps:

[0051] (1) Take 190 g of 1,2 - benzisothiazolin - 3 - one and place it in a reaction kettle, then add 380 g of water, heat up to 50 °C, add 30% sodium hydroxide to adjust the pH value to 9, consuming about 133 g of the alkali solution, to obtain a 1,2 - benzisothiazolin - 3 - one alkali solution;

[0052] (2) Add 0.1 g of sulfamic acid to the 1,2 - benzisothiazolin - 3 - one alkali solution described in step (1), and continue to stir and react at 50 °C for 2 hours to obtain a deodorized 1,2 - benzisothiazolin - 3 - one alkali solution;

[0053] (3) Add hydrochloric acid to the deodorized 1,2 - benzisothiazolin - 3 - one alkali solution described in step (2), adjust the pH value of the solution to 5.5, a large amount of white solid will precipitate, filter and dry to obtain odorless 1,2 - benzisothiazolin - 3 - one.

[0054] The content of the odor substance detected by liquid - phase external standard is 0.1 ppm.

[0055] Comparative Example 1

[0056] The difference from Example 2 is that no deodorant is added in step (2).

[0057] Liquid-phase external standard test, the content of odor substances is 4.5 ppm.

[0058] Perform performance tests on the products prepared in Examples 1-4 and Comparative Example 1, and the results are as follows:

[0059]

[0060] Note: ND means not detected.

[0061] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and retouches can be made, and these improvements and retouches should also be regarded as the protection scope of the present invention.

Claims

1. A method for removing the pungent odor in 1,2-benzisothiazol-3-one, characterized in that, It includes the following steps: (1) Add 1,2-benzisothiazol-3-one into water, and adjust the pH value to 8.5 - 11.5 with an alkali to obtain a 1,2-benzisothiazol-3-one alkali solution; (2) Add an odor remover to the 1,2-benzisothiazol-3-one alkali solution described in step (1), and react for 0.1 - 4 hours to obtain a deodorized 1,2-benzisothiazol-3-one alkali solution; (3) Add an acid to the deodorized 1,2-benzisothiazol-3-one alkali solution described in step (2) to adjust the pH value of the solution within the range of 3 - 7, thus obtaining odorless 1,2-benzisothiazol-3-one; The odor remover described in step (2) is selected from at least one of urea, ammonia water, and sulfamic acid.

2. The method for removing the pungent odor in 1,2-benzisothiazol-3-one according to claim 1, characterized in that, The alkali described in step (1) is any one of sodium hydroxide and potassium hydroxide.

3. The method for removing the pungent odor in 1,2-benzisothiazol-3-one according to claim 1, wherein The pH value described in step (1) is within the range of 9.5 - 10.

5.

4. The method for removing the pungent odor in 1,2-benzisothiazol-3-one according to claim 1, characterized in that, The temperature of the reaction described in step (2) is 25 - 100 °C.

5. The method for removing the pungent odor in 1,2-benzisothiazol-3-one according to claim 1, characterized in that, The temperature of the reaction described in step (2) is 50 - 70 °C.

6. The method for removing the pungent odor in 1,2-benzisothiazol-3-one according to claim 1, characterized in that, The dosage of the odor remover described in step (2) is 0.01% - 0.5% of the mass of 1,2-benzisothiazol-3-one.

7. The method for removing the pungent odor in 1,2-benzisothiazol-3-one according to claim 1, wherein The dosage of the odor remover described in step (2) is 0.01% - 0.05% of the mass of 1,2-benzisothiazol-3-one.

8. The method for removing the pungent odor in 1,2-benzisothiazol-3-one according to claim 1, wherein, The acid described in step (3) is at least one of hydrochloric acid, sulfuric acid, and phosphoric acid.

9. The method for removing the pungent odor in 1,2-benzisothiazol-3-one according to claim 1, wherein The acid described in step (3) is hydrochloric acid.

Images