p -phenylenediamine

Structural formula
General
Surname	p -phenylenediamine
other names	1,4-diaminobenzene; 1,4-phenylenediamine; CI 76060;
Molecular formula	C 6 H 8 N 2
Brief description	Difficult to ignite, crystalline colorless to pale red solid
External identifiers / databases
EC number	203-404-7
ECHA InfoCard	100.003.096
PubChem	7814
ChemSpider	13835179
DrugBank	DB14141
Wikidata	Q415024
properties
Molar mass	108.14 g mol −1
Physical state	firmly
density	1.135 g cm −3 (20 ° C )
Melting point	140 ° C
boiling point	267 ° C
solubility	soluble in water (40 g l −1 at 24 ° C)
safety instructions
H and P phrases	H: 301-311-331-319-317-410
	P: 280-273-304 + 340-302 + 352-305 + 351 + 338-309 + 310
Toxicological data	80 mg kg −1 ( LD 50 , rabbit , transdermal ) ; 0.92 mg l −1 ( LC 50 , rat , inh. , 4 h) ;
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

p -Phenylenediamine is a chemical compound from the group of phenylenediamines .

Extraction and presentation

p -phenylenediamine can be synthesized by several methods. Most often, 4-nitrochlorobenzene is reacted with ammonia and the 4-nitroaniline obtained is then hydrogenated:

{\ displaystyle \ mathrm {ClC_ {6} H_ {4} NO_ {2} +2 \ NH_ {3} \ longrightarrow H_ {2} NC_ {6} H_ {4} NO_ {2} + NH_ {4} Cl} }

{\ displaystyle \ mathrm {H_ {2} NC_ {6} H_ {4} NO_ {2} +3 \ H_ {2} \ longrightarrow H_ {2} NC_ {6} H_ {4} NH_ {2} +2 \ H_ {2} O}}

In the process used by DuPont, aniline is reacted with diphenyltriazine by acid catalysis to form 4-aminoazobenzene and this is hydrogenated to p- phenylenediamine.

properties

p- phenylenediamine is a crystalline, colorless to pale red solid that is soluble in water. The flash point is 156 ° C, the ignition temperature 567 ° C and the lower explosion limit 1.5%.

use

The plastics industry produces large quantities of p- phenylenediamine for the manufacture of aromatic polyamides . Together with terephthalic acid, it is an essential component of the aramids . p- phenylenediamine is an intermediate product in the manufacture of azo dyes . The synthetic pathways for some pharmaceuticals and photochemicals are just as often via this compound. Because of its coloring properties, p- phenylenediamine and some of its derivatives are used in cosmetics (especially for hair dyes, this use was discovered by Ernst Erdmann in 1888 ). Presumably, many hairdresser allergic reactions are based on contact with this dye . In some photographic developers , the alkaline solution of p -phenylenediamine is the active component. This was discovered by Andresen in 1888.

In 1863, Haussman found that a mixture of para-phenylenediamine and an oxidizing agent caused discoloration. In 1883 the first patent for exploiting this observation in hair coloring was acquired by Monnet, who actually used 2,5-diaminotoluene and hydrogen peroxide. Shortly thereafter, patents were obtained from H. and E. Erdmann for the period 1888-1897 for the use as hair colorants of a variety of para-phenylenediamines and aminophenols with hydrogen peroxide.

p- phenylenediamine is used as a detection reagent for lichen acids (e.g. fumarprotocetraric acid ). A freshly prepared solution of 10 mg p -phenylenediamine in 10 mL ethanol is used for this. In addition to viewing in daylight, the evaluation is carried out by fluorescence in UV ₃₆₅ light.

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Entry on p-phenylenediamine in the GESTIS substance database of the IFA , accessed on December 30, 2019(JavaScript required) .
↑ Entry on p-phenylenediamine in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on December 30, 2019. Manufacturers or distributors can expand the harmonized classification and labeling .
↑ ^a ^b Entry on 1,4-benzenediamine in the Hazardous Substances Data Bank , accessed April 21, 2017.
^ Ullmann's Encyclopedia of Industrial Chemistry . Wiley-VCH Verlag & Co. KGaA, 2000, ISBN 978-3-527-30673-2 , Phenylene- and Toluenediamines, doi : 10.1002 / 14356007.a19_405 .
^ Ralph Jacobson, Sidney Ray, Geoffrey G. Attridge, Norman Axford: Manual of Photography . Taylor & Francis, 2000, ISBN 978-1-136-09118-6 , pp. 275 ( limited preview in Google Book Search).
^ IARC Monographs: Occupational Exposures of Hairdressers and Barbers and Personal Use of Hair Colourants .
↑ Egon Stahl, Werner Schild: Isolation and characterization of natural substances . 1st edition. Gustav Fischer Verlag, Stuttgart / New York 1986, ISBN 3-437-30511-5 , p. 174 .

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Entry on p-phenylenediamine in the GESTIS substance database of the IFA , accessed on December 30, 2019(JavaScript required) .

[CLP_100.003.096-2] Entry on p-phenylenediamine in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on December 30, 2019. Manufacturers or distributors can expand the harmonized classification and labeling .

[HSDB-3] Entry on 1,4-benzenediamine in the Hazardous Substances Data Bank , accessed April 21, 2017.

[4] Ullmann's Encyclopedia of Industrial Chemistry . Wiley-VCH Verlag & Co. KGaA, 2000, ISBN 978-3-527-30673-2 , Phenylene- and Toluenediamines, doi : 10.1002 / 14356007.a19_405 .

[Ralph_Jacobson,_Sidney_Ray,_Geoffrey_G._Attridge,_Norman_Axford-5] Ralph Jacobson, Sidney Ray, Geoffrey G. Attridge, Norman Axford: Manual of Photography . Taylor & Francis, 2000, ISBN 978-1-136-09118-6 , pp. 275 ( limited preview in Google Book Search).

[IARC-6] IARC Monographs: Occupational Exposures of Hairdressers and Barbers and Personal Use of Hair Colourants .

[7] Egon Stahl, Werner Schild: Isolation and characterization of natural substances . 1st edition. Gustav Fischer Verlag, Stuttgart / New York 1986, ISBN 3-437-30511-5 , p. 174 .