2,5-Diaminotoluene

2,5-Diaminotoluene is an organic compound with the formula C₆H₃(NH₂)₂CH₃. It is one isomer of six with this formula. 2,5-Diaminotoluene is a colorless crystalline solid, although commercial samples are often colored owing to air oxidation. It is commonly used in hair coloring.[2]

2,5-Diaminotoluene

Names
Preferred IUPAC name 2-Methylbenzene-1,4-diamine
Other names 2-Methyl-1,4-benzenediamine Toluene-2,5-diamine 2,5-Diaminotoluene
Identifiers
CAS Number	95-70-5
3D model (JSmol)	Interactive image
Beilstein Reference	774521
ChEBI	CHEBI:53619
ChemSpider	6982
ECHA InfoCard	100.002.221
EC Number	202-442-1
KEGG	C19386
PubChem CID	7252
UNII	24JO8Z0RJU
CompTox Dashboard (EPA)	DTXSID6029123
InChI InChI=1S/C7H10N2/c1-5-4-6(8)2-3-7(5)9/h2-4H,8-9H2,1H3 Key: OBCSAIDCZQSFQH-UHFFFAOYSA-N
SMILES CC1=C(C=CC(=C1)N)N
Properties
Chemical formula	C7H10N2
Molar mass	122.17
Appearance	off white crystals
Density	1.107 g/cm^3
Melting point	64 °C (147 °F; 337 K)
Boiling point	273 °C (523 °F; 546 K)
Hazards
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	H301, H312, H317, H319, H332, H411
GHS precautionary statements	P261, P264, P270, P271, P272, P273, P280, P301+310, P302+352, P304+312, P304+340, P305+351+338, P312, P321, P322, P330, P333+313, P337+313, P363, P391, P405, P501
Flash point	no
NIOSH (US health exposure limits):
PEL (Permissible)	none[1]
REL (Recommended)	Ca[1]
IDLH (Immediate danger)	Ca [N.D.][1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Formation and use

2,5-Diaminotoluene is prepared through electrolytic reduction of 2,5-dinitrotoluene.[3] Other methods include the reductive cleavage of 4-amino-2,3'-dimethylazobenzene as well as the condensation of 2-amino-1-methylbenzene and toluene-4-sulphonyl chloride to produce 4-toluenesulphono-2-toluidide which is then coupled with diazotized aminobenzenesulphonic acid and reduced.[3]

2,5-Diaminotoluene is a substitute for phenylenediamine (1,4-diaminobenzene) in commercial hair dyes. It is preferred because of its lower toxicity. However, many home hair dyes still use phenylenediamine. In these applications, these diamines function as a primary intermediate, which means that it is first oxidized with hydrogen peroxide and then combined with a coupler to form the hair dye.[2] 2,5-Diaminotoluene is commonly used to produce black, drab and warm browns, and shades of blonde and gray hair dyes.[3]

2,5-Diaminotoluene is also known to be used in the production of dyes for textiles, furs, leathers, biological stains and indicators, wood stains, and pigments. Two examples of dyes produced by 2,5-diaminotoluene are Cl Basic Red 2 and Cl Acid Brown 103.[3]

References

1. NIOSH Pocket Guide to Chemical Hazards. "#0620". National Institute for Occupational Safety and Health (NIOSH).
2. T. Clausen (2006). "Hair Preparations". Ullmann’s Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a12_571.pub2.
3. C. Burnett, W. Bergfeld, D. Velsito, C. Klaassen, J. Marks, Jr, R. Shank, T. Slaga, P. Snyder, and F. Andersen "Final Amended Report of the Safety Assessment of Toluene-2,5-Diamine, Toluene-2,5-Diamine Sulfate, and Toluene-3,4-Diamine as Used in Cosmetics" in International Journal of Toxicology, 2010, vol 29, pages 61S-83S