N -methylaniline

Structural formula
General
Surname	N -methylaniline
other names	N -methyl- N -phenylamine N -methylphenylamine N -methylaminobenzene Monomethylaniline NMA
Molecular formula	C 7 H 9 N
Brief description	colorless to yellowish oily liquid with an aniline-like odor
External identifiers / databases
CAS number 100-61-8 EC number 202-870-9 ECHA InfoCard 100.002.610 PubChem 7515 ChemSpider 7234 Wikidata Q1959597
properties
Molar mass	107.16 g mol −1
Physical state	liquid
density	0.99 g cm −3 (20 ° C)
Melting point	-57 ° C
boiling point	196 ° C
Vapor pressure	1.59 h Pa (40 ° C) 3.02 h Pa (50 ° C)
solubility	poor in water (5.62 g l −1 at 20 ° C) soluble in ethanol, ether and chloroform
Refractive index	1.571 (20 ° C)
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 301-311-331-373-410 P: 260-280-273-302 + 350-304 + 340-312
MAK	Switzerland: 0.5 ml m −3 or 2.2 mg m −3
Toxicological data	360 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

N -Methylaniline is a chemical compound from the group of secondary amines and is isomeric to toluidines . It is in the form of a colorless to yellowish liquid with an aniline-like odor that turns dark in air.

Extraction and presentation

N -Methylaniline can be produced by reacting aniline and methanol under pressure at 230 ° C and adding an acidic catalyst such as sulfuric acid or hydrogen chloride :

${\displaystyle \mathrm {C_{6}H_{5}{-}NH_{2}+CH_{3}OH\ {\xrightarrow[{230^{\circ }C,\ Druck}]{H_{2}SO_{4}\,/\,HCl}}} }$ ${\displaystyle \mathrm {C_{6}H_{5}{-}NH{-}CH_{3}+H_{2}O} }$

Aniline and methanol react with sulfuric acid or hydrogen chloride as a catalyst to form N -methylaniline and water.

A more recent method is the reaction of aniline and formaldehyde with subsequent hydrogenation of the intermediate product N-methylideneaniline . Particularly easily extend both reactions on zeolite Y - catalyst . NMR spectroscopic investigations showed that when zeolite is used, the methanol is first oxidized to formaldehyde.

${\displaystyle \mathrm {C_{6}H_{5}{-}NH_{2}+CH_{2}O\ {\xrightarrow {Zeolith-Kat.}}\ \ C_{6}H_{5}{-}N{=}CH_{2}+H_{2}O} }$

Aniline and formaldehyde react on the zeolite catalyst to form N -methylideneaniline and water.

${\displaystyle \mathrm {C_{6}H_{5}{-}N{=}CH_{2}+H_{2}\ {\xrightarrow {Zeolith-Kat.}}\ \ C_{6}H_{5}{-}NH{-}CH_{3}} }$

N -methylidene aniline is hydrogenated to N -methylaniline on a zeolite catalyst .

properties

The basicity of N-methylaniline is higher than that of aniline because of the additional methyl group , but lower than that of most aliphatic amines.

use

N -methylaniline is used as an intermediate in the manufacture of dyes and other chemical compounds and as an additive for fuels.

Due to its refractive index , it can be used in the determination of emeralds with the help of the immersion method.

Safety instructions / risk assessment

The vapors of N -methylaniline can form an explosive mixture with air ( flash point 78 ° C, ignition temperature 500 ° C). N -Methylaniline is electrostatically charged by movement in the liquid. Contact with nitrosating compounds can lead to the formation of carcinogenic N -nitrosomethylaniline .

In 2019, N -methylaniline was included in the EU's ongoing action plan ( CoRAP ) in accordance with Regulation (EC) No. 1907/2006 (REACH) as part of substance evaluation . The effects of the substance on human health and the environment are re-evaluated and, if necessary, follow-up measures are initiated. Ingestion of N- methylaniline was driven by concerns about cumulative exposure , worker exposure , high risk characterization ratio (RCR) and widespread use, as well as the potential dangers of carcinogenic and mutagenic properties. The re-evaluation should be carried out by Poland from 2021 .

Individual evidence

1. ↑ ^{a b c d e f g h i} Entry on N-methylaniline in the GESTIS substance database of the IFA , accessed on January 8, 2020(JavaScript required) .
2. ↑ wxyschem: N-methylaniline
3. ↑ Data sheet N-Methylaniline from Sigma-Aldrich , accessed on November 3, 2016 ( PDF ).
4. ↑ Entry on N-methylaniline in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
5. ↑ Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values (search for 100-61-8 or N-methylaniline ), accessed on November 2, 2015.
6. ↑ Data sheet N-methylaniline from AlfaAesar, accessed on December 15, 2010 ( PDF )(JavaScript required) .
7. ↑ Science online lexica: Entry on N-methylaniline in the lexicon of chemistry. Retrieved August 26, 2009.
8. ^ EV Steen (ed.), C. Claeys (ed.): Recent advances in the science and technology of zeolites and related materials: proceedings of the 14th International Zeolite Conference, Cape Town, South Africa, 25-30. April 2004, Part 3, Gulf Professional Publishing, 2004, ISBN 978-0-444-51825-5 , pp. 2221-2227.
9. ^ GA Webb, AE Aliev: Nuclear Magnetic Resonance. Volume 32, Royal Society of Chemistry, 2003, ISBN 978-0-85404-342-2 , p. 277.
10. ↑ EG Derouane (Ed.): Principles and methods for accelerated catalyst design and testing. Volume 69 of NATO Science Series, Springer, 2002, ISBN 978-1-4020-0720-0 , p. 429.
11. ↑ Betriebsstoffe.ch: Additives for petrol ( Memento of the original from August 29, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
12. ↑ Community rolling action plan ( CoRAP ) of the European Chemicals Agency (ECHA): N-methylaniline , accessed on March 26, 2019.