Reactive Black 5

Structural formula
General
Surname	Reactive Black 5
other names	Tetrasodium 4-amino-5-hydroxy-3,6-bis [("E") - (4 - {[2- (sulfonatooxy) ethyl] sulfonyl} phenyl) diazenyl] -2,7-naphthalene disulfonate ( IUPAC ) CI 20505 Remazol Black B
Molecular formula	C 26 H 21 N 5 Na 4 O 19 S 6
Brief description	dark brown powder
External identifiers / databases
CAS number 17095-24-8 EC number 241-164-5 ECHA InfoCard 100.037.407 PubChem 135442967 ChemSpider 13657666 Wikidata Q27124180
properties
Molar mass	991.8 g mol −1
Physical state	firmly
density	1.21 g cm −3
Melting point	> 180 ° C
solubility	550 g l −1
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 317-334 P: 261-280-342 + 311
Toxicological data	> 5000 mg kg −1 ( LD 50 , rat, female , oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

CI Reactive Black 5 is a bisazo dye of the performance group of reactive dyes , which for dyeing of cotton and wool is used.

Manufacturing

Reactive Black 5 ( 5 ) is synthesized by diazotizing parabase ester ( 1 ) with sodium nitrite to form diazo component 2 and coupling with H acid ( 3 ). First, the two components are converted to the red monoazo dye ( 4 ) at a low pH ( acidic coupling ) . Then, at a higher pH, the diazo component is coupled adjacent to the hydroxyl group of the H-acid ( alkaline coupling ):

Synthesis of CI Reactive Black 5

Depending on the reaction conditions ( stoichiometry , concentration ), the end product contains proportions of the two isomeric red monoazo dyes in which the azo group is adjacent to the amino group ( 4 ) or to the hydroxy group of the H-acid.

use

Reactive Black 5 is one of the first vinyl sulfone dyes for which a patent was applied for by Farbwerke Hoechst in 1952 and which was marketed under the trade name Remazol Black B from 1957 . It was the first reactive dye with two reactive groups in the molecule. Since the two reactive groups are identical, one speaks of a homobifunctional reactive dye.

With Reactive Black 5, a navy blue to black shade can be achieved on cotton and wool. In combination with red or orange dyes, deep black colors are obtained. Reactive Black 5 is the largest and most widely used reactive dye in the world.

Individual evidence

1. ↑ ^{a b c d e f g} Data sheet Reactive Black 5 at Sigma-Aldrich , accessed on November 4, 2019 ( PDF ).
2. ↑ There is not yet a harmonized classification for this substance . A labeling of CI Reactive Black 5 in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), retrieved on November 04, 2019, is reproduced from a self-classification by the distributor .
3. ↑ Karl Rebsamen: From colorless chemicals to colored textiles . In: Science in chemistry lessons . tape 87 . Friedrich-Verlag, Hanover May 2005, p. 48 .
4. ↑ Patent DE965902 : Process for fixing water- soluble organic compounds on substrates with a fibrous structure. Registered on April 3, 1952 , published on September 19, 1957 , applicant: Hoechst AG, inventor: Johannes Heyna, Willy Schumacher. ‌
5. ↑ J. Heyna: reactive dyes with vinyl sulfone groups . In: Angewandte Chemie . tape 74 , no. 24 , December 21, 1962, pp. 966 , doi : 10.1002 / anie.19620742403 .
6. ↑ ^{a b} Entry on Reactive Black 5. In: Römpp Online . Georg Thieme Verlag, accessed on November 5, 2019.