p -toluidine

Structural formula
General
Surname	p -toluidine
other names	para -toluidine; 4-aminotoluene; p -methylaniline; para -methylaniline; 4-methylaniline; p -aminotoluene; 1-amino-4-methylbenzene;
Molecular formula	C 7 H 9 N
Brief description	colorless to red-brown solid with a wine-like odor
External identifiers / databases
EC number	203-403-1
ECHA InfoCard	100.003.095
PubChem	7813
ChemSpider	13835151
Wikidata	Q2043499
properties
Molar mass	107.16 g mol −1
Physical state	firmly
density	1.05 g cm −3
Melting point	45 ° C
boiling point	200 ° C
Vapor pressure	2.1 mbar (50 ° C)
pK s value	5.08 (the conjugate acid BH + )
solubility	poorly soluble in water (7.5 g l −1 at 20 ° C)
Refractive index	1.5534
safety instructions
H and P phrases	H: 331-311-301-351-319-317-411
	P: 280-302 + 350-304 + 340-305 + 351 + 338-301 + 310-273
MAK	Switzerland: 0.2 ml m −3
Toxicological data	336 mg kg −1 ( LD 50 , rat , oral ) ; 890 mg kg −1 ( LD 50 , rabbit , transdermal ) ;
	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

p -Toluidine is a chemical compound from the group of aromatic, singly methylated anilines and is isomeric to o -toluidine and m -toluidine .

Extraction and presentation

All three isomeric toluidines are produced from nitrotoluenes ( accessible from toluene by nitration ) by reduction. The reduction can be carried out on the one hand with iron, acetic acid and hydrochloric acid ( Béchamp reduction ). Today, catalytic hydrogenation with Raney nickel predominates . The solvents used here are often lower, aliphatic alcohols ( methanol , ethanol , n-propanol or iso-propanol ). The hydrogenation generally takes place at pressures between 3 bar and 20 bar H ₂ pressure (so-called low-pressure hydrogenation) or at 20 to 50 bar (so-called medium-pressure hydrogenation ).

properties

p -Toluidine is a flammable, colorless to yellowish solid, which turns reddish-brown when exposed to light and air, has a wine-like odor and is sparingly soluble in water. It has a conductivity of 6.2 × 10 ⁻⁶ S / m at 100 ° C.

All Toluidine are weak bases , their (pK _s values) are in the same order of magnitude as aniline (4,603).

According to Antoine, the vapor pressure functions result according to log ₁₀ ( p ) = A− (B / ( T + C)) ( p in bar, T in K) as follows:

Vapor pressure functions of the toluidines
Type	T in K	A.	B.	C.
o -Toluidine	391.6-473.4	4.19168	1617.232	-87.126
m -toluidine	394.9-476.5	4.19983	1618.386	−90.631
p -toluidine	315-473.5	4.71884	1961,716	−57.0

use

The toluidines used to be of great importance almost exclusively as intermediate products for the production of dyes and pigments . o - and p -Toluidin are important starting materials for the production of Chlortoluidinen and nitrided toluidines. In addition to toluidinesulfonic acids , these are used to manufacture pharmaceuticals , dyes and pigments.

The cresols can be obtained from the toluidines via diazotization (and subsequent “ boiling ”) .

p -Toluidine is used as a reagent for lignin, nitrite, phloroglucinol and is used in the production of dyes , textile auxiliaries and vulcanization accelerators.

Important azo dyes based on p -toluidine are the cationic dye C.I. Basic Red 9 ( CI 42500) and the acid dye CI Acid Green 25 (CI 61570).

Via diazotization and subsequent reduction of the p -toluidine, p -tolylhydrazine (cf. hydrazine ) can be obtained, which is used as a precursor for 3-methyl-1- [ p -tolyl] -5-pyrazolone (important intermediate dye; cf. also : Pyrazolone ) is used.

For the production of triphenylmethane dyes and for 2,9-dimethylquinacridone (cf. quinacridone pigments ), p -toluidine is also used in large quantities.

Furthermore, it is also used for the production of some pesticides such as Oxythiochinox , tolylfluanid or safeners daimuron and many pharmaceuticals.

Chemical structure	Surname	use
	3-chloro-4-methylaniline	for the production of 3-chloro-4-methyl-6-nitroaniline in order to obtain the herbicide chlorotoluron from it; in the USA as an avicide against starlings and gulls
	4-aminotoluene-2-sulfonic acid	as an intermediate for azo dyes and optical brighteners
	4-aminotoluene-3-sulfonic acid	serves (after diazotization and reduction to the corresponding hydrazine) for the production of important pyrazolones
	4-aminotoluene-2-sulfonic acid anilide	as a diazo component for azo dyes
	4-amino-6-chlorotoluene-3-sulfonic acid	as a diazo component for azo dyes and precursor for pyrazolones

safety instructions

The vapors of p -toluidine can form an explosive mixture with air ( flash point 87 ° C, ignition temperature 482 ° C).

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m entry on p-toluidine in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
↑ ^a ^b Zvi Rappoport (Ed.): CRC Handbook of Tables for Organic Compound Identification . 3 ^rd Edition, CRC Press / Taylor and Francis, Boca Raton, FL, 1967, ISBN 0-8493-0303-6 , Acid Dissociation Constants of Organic Bases in Aqueous Solution, S. 437th
↑ ^a ^b J.S. Bowers, Jr .: Toluidines in Ullmann's Encyclopedia of Industrial Chemistry, 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, doi : 10.1002 / 14356007.a27_159 .
↑ Entry on p-toluidine 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 .
↑ Swiss Accident Insurance Fund (Suva): Limit values - current MAK and BAT values (search for 106-49-0 or p-toluidine ), accessed on November 2, 2015.
↑ ^a ^b R. R. Dreisbach, SA Shrader: Vapor Pressure Temperature Data on Some Organic Compounds . In: Ind. Eng. Chem. Band 41 , no. 12 , 1949, pp. 2879-2880 , doi : 10.1021 / ie50480a054 .
^ Daniel R. Stull: Vapor Pressure of Pure Substances. Organic and Inorganic Compounds . In: Ind. Eng. Chem. Band 39 , no. 4 , 1947, pp. 517-540 , doi : 10.1021 / ie50448a022 .
↑ James F. Glahn: Use Of Starlicide To Reduce Starling Damage At Livestock Feeding Operations , University of Nebraska - Lincoln, 1981.

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m entry on p-toluidine in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .

[CRC_O-2] Zvi Rappoport (Ed.): CRC Handbook of Tables for Organic Compound Identification . 3 ^rd Edition, CRC Press / Taylor and Francis, Boca Raton, FL, 1967, ISBN 0-8493-0303-6 , Acid Dissociation Constants of Organic Bases in Aqueous Solution, S. 437th

[Ullmann-3] J.S. Bowers, Jr .: Toluidines in Ullmann's Encyclopedia of Industrial Chemistry, 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, doi : 10.1002 / 14356007.a27_159 .

[CLP_100.003.095-4] Entry on p-toluidine 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 106-49-0 or p-toluidine ), accessed on November 2, 2015.

[Dreisbach-6] R. R. Dreisbach, SA Shrader: Vapor Pressure Temperature Data on Some Organic Compounds . In: Ind. Eng. Chem. Band 41 , no. 12 , 1949, pp. 2879-2880 , doi : 10.1021 / ie50480a054 .

[Stull-7] Daniel R. Stull: Vapor Pressure of Pure Substances. Organic and Inorganic Compounds . In: Ind. Eng. Chem. Band 39 , no. 4 , 1947, pp. 517-540 , doi : 10.1021 / ie50448a022 .

[8] James F. Glahn: Use Of Starlicide To Reduce Starling Damage At Livestock Feeding Operations , University of Nebraska - Lincoln, 1981.