Butylbenzisothiazolinone

Structural formula
General
Surname	Butylbenzisothiazolinone
other names	2-butyl-1,2-benzisothiazol-3 (2 H ) -one 2-butyl-benzo [ d ] isothiazol-3-one N -butyl-1,2-benzisothiazolin-3-one BBIT
Molecular formula	C 11 H 13 NOS
Brief description	yellow to brown oily liquid
External identifiers / databases
CAS number 4299-07-4 EC number 420-590-7 ECHA InfoCard 100.101.927 PubChem 9837171 ChemSpider 8012892 Wikidata Q87988170
properties
Molar mass	151.16
Physical state	liquid
density	1.177 g cm −3 at 20 ° C
boiling point	333 ° C
Vapor pressure	1.5 Pa (25 ° C)
solubility	soluble in water and in various organic solvents
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 314-317-410 P: ?
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Butylbenzisothiazolinon BBIT is a biocide from the class of benzo-fused isothiazolinones , like the basic substance Benzisothiazolinon BIT, from which it can be obtained by alkylation e.g. B. arises with 1-bromobutane .

BBIT is particularly active as a fungicide and is being evaluated in the EU for product types 6, 7, 9, 10 and 13 (as of March 2020).

Occurrence and representation

For the frequently used starting material benzisothiazolinone BIT, a large number of syntheses have been developed since the first description in 1923 because of the originally unsatisfactory yields and the use of problematic reactants , such as B. recently from 2-iodobenzamide and carbon disulfide CS ₂ in the presence of copper (I) bromide CuBr and the amino acid L-proline with yields of over 75%.

The alkylation of the lithium salt of BIT with 1-bromobutane gives a mixture of N- butyl-1,2-benzisothiazolin-3-one (BBIT) and the undesired O -alkylation product 3-butoxy-1,2-benzisothiazoline in a ratio of 79:21 , from which BBIT can be isolated by vacuum distillation .

Another synthesis is based on 2-chloro- N- butylbenzamide (prepared from 2-chlorobenzoic acid via the acid chloride with n-butylamine ), which is reacted with dry sodium sulfide Na ₂ S in NMP to form 2-mercapto- N- butylbenzamide.

The isothiazolinone ring is closed by oxidative cyclization with sulfuryl chloride SO ₂ Cl ₂ and BBIT is formed in 74% yield.

properties

Butylbenzisothiazolinone is a yellow to brown oil that dissolves in water and various organic solvents. The compound is stable in the pH range between 2 and 12 and at higher temperatures. 2-Butyl-benzo [d] isothiazol-3-one reacts as isothiazolinone with thiol functions of peptides , such as. B. glutathione , or enzymes inside the cells of microorganisms and thus block cell growth and division.

Applications

Butylbenzisothiazolinone is a biocide that is closely related to the antimicrobially active isothiazolinones . It is active against fungi, yeasts, various algae and some types of bacteria, but less so against problem germs such as pseudomonads .

Particularly because of its mushroom growth inhibitory effect Butylbenzisothiazolinon is in cooling lubricants and water-based paints as so-called in-can preservatives (engl. In-can preservative ), and because of its good UV-stability (low yellowing tendency) for the antimicrobial finishing of plastic materials, such. B. Polyurethanes PUR, polyvinyl chloride PVC, polyolefins and ethylene-vinyl acetate copolymer EVAC used in amounts of 500 to 5,000 ppm.

Individual evidence

1. ↑ Patent US6608208B1 : Process for the preparation of 1,2-benzisothiazolin-3-ones. Applied on April 26, 1999 , published on August 19, 2003 , applicant: Zeneca Ltd., inventor: MR James. ‌
2. ^ ^{A b} T. Li, L. Yang, K. Ni, Z. Shi, F. Li, D. Chen: An efficient approach to construct benzisothiazol-3 (2 H ) -ones via copper-catalyzed consecutive reaction of 2- halobenzamides and carbon disulfide . In: Org. Biomolec. Chem. Band 26 , no. 14 , 2016, p. 6297-6303 , doi : 10.1039 / C6OB00819D .
3. ↑ ^{a b} Anna Wypych, George Wypych: Databook of Biocides: Biocides Included in Article 95 List . ChemTec Publishing, Toronto 2015, ISBN 978-1-895198-89-8 , pp. 84 .
4. ↑ ^{a b c d} Frank Sauer: Microbicides in Coatings . Vincentz Network GmbH & Co. KG, Hanover 2017, ISBN 978-3-86630-897-8 , p. 67-68 .
5. ↑ Entry on 2-n-butyl-benzo (d) isothiazol-3-one in the GESTIS substance database of the IFA , accessed on March 15, 2020(JavaScript required) .
6. ↑ Entry on 2-n-butyl-benzo [d] isothiazol-3-one in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on March 22, 2020. Manufacturers or distributors can expand the harmonized classification and labeling .
7. ↑ Entries for CAS no. 4299-07-4 in the ECHA database on Biocidal Active Substances, accessed on March 3, 2020.
8. ↑ M. McKibben, EW McClelland: XXI-Production and reactions of 2-dithiobenzoyl . In: J. Chem. Soc., Faraday Trans. Volume 123 , 1923, pp. 170-173 , doi : 10.1039 / CT9232300170 .
9. ^ ^{A b} V. Silva, C. Silva, P. Soares, EM Garrido, F. Borges, J. Garrido: Isothiazolinone biocides: Chemistry, biological, and toxicity profiles . In: Molecules . tape 25 , no. 4 , 2020, p. 991- , doi : 10.3390 / molecules.25040991 .
10. ↑ Patent US8884024B1 : Process for preparing benzisothiazolinones. Applied on September 25, 2013 , published on November 11, 2014 , applicant: Titan Chemicals Ltd., inventor: IR Marsh. ‌
11. ↑ Patent US9067899B2 : Process for preparing 1,2-benzoisothiazolin-3-ones. Applied on April 23, 2013 , published June 30, 2015 , Applicant: Titan Chemicals Ltd., Inventor: C. Berg, S. Singh, IR Marsh. ‌