Metol
This article needs additional citations for verification. (June 2019) |
Names | |
---|---|
IUPAC name
4-(methylamino)phenol sulfate
| |
Other names
N-methyl-p-aminophenol sulfate, Pictol, p-(methylamino)phenol sulfate, monomethyl-p-aminophenol hemisulfate, Metol, Elon, Rhodol, Enel, Viterol, Scalol, Genol, Satrapol, Photol.
| |
Identifiers | |
3D model (
JSmol ) |
|
ChEBI | |
ChemSpider | |
ECHA InfoCard
|
100.000.216 |
KEGG | |
PubChem CID
|
|
UNII | |
CompTox Dashboard (EPA)
|
|
| |
| |
Properties | |
(C7H10NO)2SO4 | |
Molar mass | 344.38 g/mol |
Melting point | 260 °C (500 °F; 533 K) |
Hazards | |
GHS labelling:[1] | |
Warning | |
H302, H317, H373, H410 | |
P260, P280, P301+P312+P330 | |
Safety data sheet (SDS) | Oxford MSDS |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|
Metol (or Elon) is a trade name for the
Synthesis
Several methods exist for the preparation of N-methylaminophenol. It arises by decarboxylation of N-4-hydroxyphenylglycine (Glycin). It can be obtained by reaction of hydroquinone with methylamine.[3]
Application
Metol is an excellent developing agent for most continuous tone developer applications, and it has been widely used in published developer formulas as well as commercial products. However, it is difficult to produce highly concentrated developer solutions using Metol, and therefore most Metol developers are supplied in dry chemical mix. A developer containing both Metol and hydroquinone is called an MQ developer. This combination of agents provides greater developer activity since the rate of development by both agents together is greater than the sum of rates of development by each agent used alone (superadditivity). This combination is very versatile; by varying the quantities of Metol, hydroquinone, and restrainer, and adjusting the pH, the entire range of continuous tone developers can be made. Therefore, this form of Metol replaced most other developing agents except for hydroquinone, Phenidone (which is more recent than Metol), and derivatives of Phenidone. Notable formulas include Eastman Kodak D-76 film developer, D-72 print developer, and D-96 motion picture negative developer.
History
Alfred Bogisch, working for a chemical company owned by Julius Hauff, discovered in 1891 that methylated
Because it has been in use for this purpose for over 100 years, and often by amateur photographers, there is a substantial body of evidence regarding the health problems that contact with Metol can cause. These are principally local
References
- ^ GHS: GESTIS 022920
- .