Method for preparation of 2-methyl-1,2-benzisothiazolin-3-one
View Patent ↗A method for preparation of 2-methyl-1,2-benzisothiazolin-3-one from 1,2-benzisothiazolin-3-one by contacting 1,2-benzisothiazolin-3-one with an alkali metal hydroxide and dimethyl sulfate.
1. A method for preparation of 2-methyl-1,2-benzisothiazolin-3-one from 1,2-benzisothiazolin-3-one; said method comprising contacting 1,2-benzisothiazolin-3-one with sodium hydroxide, potassium hydroxide or a combination thereof and dimethyl sulfate; wherein 1,2-benzisothiazolin-3-one is contacted with sodium hydroxide, potassium hydroxide or a combination thereof to form a mixture and dimethyl sulfate is then added to the mixture.
2. The method of claim 1 in which the peak reaction temperature during dimethyl sulfate addition is from −5° C. to 40° C.
3. The method of claim 2 in which a ratio of moles of sodium hydroxide, potassium hydroxide or a combination thereof to moles of 1,2-benzisothiazolin-3-one is from 0.7/1 to 2/1.
4. The method of claim 3 in which the peak reaction temperature is no greater than 25° C.
5. The method of claim 4 in which the ratio of moles of sodium hydroxide, potassium hydroxide or a combination thereof to moles of 1,2-benzisothiazolin-3-one is from 0.9/1 to 1.2/1.
6. The method of claim 5 in which the peak reaction temperature is no greater than 10° C.
7. The method of claim 6 in which the solvent is water.