Phenothiazine

Structural formula
General
Surname	Phenothiazine
other names	10 H -phenothiazine Thiodiphenylamine Dibenzothiazine Dibenzoparathiazine 10 H -dibenzo- [ b, e ] -1,4-thiazine Dibenzo-1,4-thiazine
Molecular formula	C 12 H 9 NS
Brief description	yellow solid with a characteristic odor
External identifiers / databases
CAS number 92-84-2 EC number 202-196-5 ECHA InfoCard 100.001.997 PubChem 7108 Wikidata Q410846
properties
Molar mass	199.28 g mol −1
Physical state	firmly
density	1.34 g cm −3
Melting point	182-185 ° C
boiling point	381 ° C (decomposition)
Vapor pressure	<0.01 hPa (40 ° C)
solubility	practically insoluble in water (0.127 mg l −1 at 23 ° C) soluble in ethanol , acetone and ether practically insoluble in chloroform
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 302-317-373-410 P: 273-280-302 + 352-314
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Phenothiazine is a chemical compound from the group of thiazines and namesake of the phenothiazines . It was first synthesized in 1883 by August Bernthsen .

Extraction and presentation

Phenothiazine is produced industrially by the catalyzed reaction of diphenylamine with 2 equivalents of sulfur as an oxidizing agent in the melt. This produces phenothiazine and, as a reduction product , hydrogen sulfide , which is removed in gaseous form. The remaining phenothiazine is purified by vacuum distillation .

${\displaystyle \mathrm {(C_{6}H_{5})_{2}NH+2\ S\longrightarrow C_{12}H_{9}NS+H_{2}S} }$

properties

Phenothiazine is a flammable, difficult to ignite, light and air-sensitive yellow solid that is present as flakes and has a characteristic odor and is practically insoluble in water. It decomposes when heated. It oxidizes very easily with the formation of 3 H -phenothiazin-3-one, 7-hydroxy-3 H -phenothiazin-3-one and phenothiazine-5-oxide.

use

Phenothiazine is used in metal-free organic dye sensitizers, dyes, and antioxidants . It is used as an antioxidant in lubricants and oils in concentrations of up to 1%, insecticide , fungicide , bactericide , starting material for the synthesis of tranquilizers and antihistamines, basic body of thiazine dyes, as a polymerization inhibitor, medicament ( anthelmintic ) in veterinary medicine , earlier also in human medicine . It was the first synthetic larvicide to be used on a large scale, especially in the United States. Its effectiveness against mosquito larvae was discovered by Campbell and his colleagues in 1934. It can therefore be seen as a forerunner of modern insecticides.

safety instructions

Phenothiazine is phototoxic in humans and animals . The oral and dermal toxicity of pure phenothiazine in rats and rabbits is low with LD ₅₀ values ​​greater than 10,000 mg phenothiazine / kg body weight. A value of more than 200,000 mg / m ^{3 is} given for the 1-hour LC ₅₀ .

Individual evidence

1. ↑ ^{a b c d e f g h} Entry on phenothiazine in the GESTIS substance database of the IFA , accessed on January 8, 2018(JavaScript required) .
2. ↑ ^{a b c d} The MAK Collection for Occupational Health and Safety: Phenothiazin (MAK Value Documentation in German language, 2009), doi : 10.1002 / 3527600418.mb9284kskd0046 (free full text).
3. ↑ ^{a b} Datasheet Phenothiazine, 98 +% from AlfaAesar, accessed on April 18, 2017 ( PDF )(JavaScript required) .
4. ^ ^{A b} Robert Lee Metcalf: The Mode of Action of Organic Insecticides . National Academies, 1948, pp. 44 ( limited preview in Google Book search).
5. ↑ Data sheet Phenothiazine, purum, ≥98.0% (GC) from Sigma-Aldrich , accessed on April 18, 2017 ( PDF ).
6. ↑ Richard Wegler: Chemistry of the pesticides and pesticides . Springer Science & Business Media, 2012, ISBN 978-3-642-46210-8 , pp. 454 ( limited preview in Google Book search).
7. ^ Gerhard H. Schmidt: Pesticides and environmental protection . Springer-Verlag, 2013, ISBN 978-3-322-83604-5 , p. 110 ( limited preview in Google Book search).