Dimethylacetamide

Structural formula
General
Surname	Dimethylacetamide
other names	N , N -dimethylacetamide ( IUPAC ) N , N -dimethylethanamide Acetic acid dimethylamide Acetyldimethylamine DMAC
Molecular formula	C 4 H 9 NO
Brief description	colorless to yellowish, oily liquid with an amine-like odor
External identifiers / databases
CAS number 127-19-5 EC number 204-826-4 ECHA InfoCard 100.004.389 PubChem 31374 ChemSpider 29107 Wikidata Q411452
properties
Molar mass	87.12 g mol −1
Physical state	liquid
density	0.94 g cm −3 (20 ° C)
Melting point	−20  ° C
boiling point	165 ° C
Vapor pressure	3.3 h Pa (20 ° C) 7.4 hPa (30 ° C) 44 hPa (50 ° C)
solubility	miscible with water miscible with common organic solvents
Refractive index	1.4341 (25 ° C)
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 360D-312 + 332-319 P: 201-302 + 352-305 + 351 + 338-308 + 313
Authorization procedure under REACH	of particular concern : toxic for reproduction ( CMR )
MAK	DFG : 10 ml m −3 or 36 mg m −3
Toxicological data	4300 mg kg −1 ( LD 50 ,  rat ,  oral ) 2240 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

Dimethylacetamide (according to IUPAC nomenclature: N , N -dimethylacetamide , also called DMAC for short ) is an organic-chemical compound from the group of carboxamides . It is a high-boiling, polar and aprotic solvent with excellent dissolving power, which is also used as an intermediate in the chemical industry .

Extraction and presentation

The industrial production of dimethylacetamide takes place by reacting methyl acetate with dimethylamine at temperatures of 90–110 ° C. and pressures of 12–25 bar in the presence of sodium methoxide in jet loop reactors .

The product is purified and worked up by multi-stage distillation in rectification columns . The yield in this reaction is more than 99% based on methyl acetate. Alternatively, in addition to methyl acetate, acetic acid can also be used and instead of methanol, water can be split off. In principle, all basic catalysts such as alkali or alkaline earth metal hydroxides , alcoholates or carbonates are suitable as catalyst systems .

properties

Physical Properties

Dimethylacetamide has a relative gas density of 3.01 (density ratio to dry air at the same temperature and pressure ) and a relative density of the vapor-air mixture of 1.01 (density ratio to dry air at 20 ° C and normal pressure ). In addition, dimethylacetamide has a vapor pressure of 3.3 hPa at 20 ° C, 7.4 hPa at 30 ° C and 44 hPa at 50 ° C. The dynamic viscosity is 1.02 mPa · s at 20 ° C. The vapor pressure curve can be calculated using the Antoine equation as log ₁₀ ( p ) = A - ( B / ( T + C )) ( p in bar, T in K) with A = 4.88722, B = 1889.1 and C. = −52.15 describe. The critical data known are the critical temperature with T _c = 384.85 ° C., the critical pressure with p _c = 40.3 bar and an acentric factor with ω _c = 0.36351.

Chemical properties

N , N -dimethylacetamide is a flammable, but hardly inflammable liquid from the group of carboxamides . It is miscible with water and the common organic solvents. Dimethylacetamide is difficult or very difficult to volatilize and is hygroscopic. Dangerous reactions can take place on contact with oxidizing agents , hexachlorocyclohexane and carbon tetrachloride . Thermal decomposition of the substance occurs due to heat. Furthermore, dimethylacetamide has an acidic reaction. An aqueous solution with a concentration of 200 g / l has a pH of approx. 4 at a temperature of 20 ° C.

use

Dimethylacetamide (DMAC) is mainly used as a polar , aprotic solvent in the chemical industry . It has an excellent dissolving power for cellulose nitrate , some cellulose ethers , chlorinated rubber , some of polyvinyl chloride grades, polyvinyl acetate , polyvinyl ethers , polyacrylates , polystyrene , styrene - maleic acid ester resins , maleinate resins, cyclohexanone resins, urea and melamine-formaldehyde resins , alkyd resins , Rosin and numerous plasticizers . It is also used as a paint remover and extraction agent , catalyst and as a crystallization aid . It is also used in its highly pure state as a solvent in spectroscopy . It is also used in the paint industry as an additive for special coating materials based on polyamides , polyamide-imides , polyamide-carboxylic acids, polyurethanes and polyvinyl chloride. A substantial part of the N, N-dimethylacetamide is used in the manufacture of fibers and films . The drug busulfan contains 33% of dimethylacetamide as a pharmaceutical excipient or solvent.

safety instructions

The vapors of dimethylacetamide can form explosive mixtures with air if the substance is heated above the flash point. Dimethylacetamide is mainly absorbed through the respiratory tract and the skin . This leads to acute irritation of the mucous membranes of the eyes and the respiratory tract as well as the skin. Furthermore, neurotoxic effects have been confirmed after massive exposure . Chronic irritation can also lead to gastrointestinal disorders , liver damage and joint pain . In addition, based on the results of numerous tests, a reproductive and teratogenic effect is strongly suspected. However, mutagenicity and carcinogenicity could be ruled out. Dimethylacetamide has a lower explosion limit (LEL) of 1.8 vol.% (64 g / m ³ ) and an upper explosion limit (UEL) of 11.5 vol.% (415 g / m ³ ). The ignition temperature is approx. 400 ° C. The substance therefore falls into temperature class T2. With a flash point of approx. 66 ° C, dimethylacetamide is considered difficult to ignite.

Web links

Commons : Dimethylacetamide  - Collection of Pictures, Videos and Audio Files

Individual evidence

1. ↑ ^{a b c d e f g h i j k l m n} Entry on N, N-dimethylacetamide in the GESTIS substance database of the IFA , accessed on September 29, 2018(JavaScript required) .
2. ↑ ^{a b c} Entry on N, N-dimethylacetamide. In: Römpp Online . Georg Thieme Verlag, accessed on September 29, 2014.
3. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-190.
4. ↑ Entry on N, N-dimethylacetamide in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on May 6, 2019. Manufacturers or distributors can expand the harmonized classification and labeling .
5. ↑ Entry in the SVHC list of the European Chemicals Agency , accessed on May 6, 2019.
6. ↑ ^{a b} Patent EP1828102B1 : Process for the production of N, N-dimethylacetamide (DMAC). Published on May 7, 2014 , applicant: BASF SE, inventor: Horst Grafmans, Steffen Maas, Alexander Weck, Heinz Rütter, Michael Schulz, Karl-Heinz Ross. ‌
7. ^ IM Smallwood: Handbook of Organic Solvent Properties. Arnold, London 1996, ISBN 0-340-64578-4 , p. 249.
8. ↑ J. Schmidt: Design of safety valves for multi-purpose systems according to ISO 4126-10. In: Chem. Ing. Techn. Volume 83, 2011, pp. 796-812, doi: 10.1002 / cite.201000202 .
9. ↑ NDA 20-954 Busulfex (busulfan) Injection (PDF)
10. ↑ G. Hempel, D. Oechtering et al: Cytotoxicity of dimethylacetamide and pharmacokinetics in children receiving intravenous busulfan. In: Journal of Clinical Oncology . Volume 25, number 13, May 2007, pp. 1772–1778, doi: 10.1200 / JCO.2006.08.8807 . PMID 17470868 .
11. ↑ D. Oechtering, J. Boos, G. Hempel: Monitoring of N, N-dimethylacetamide in children during iv-busulfan therapy by liquid chromatography-mass spectrometry. In: Journal of Chromatography B . Volume 838, Number 2, July 2006, pp. 129-134, doi: 10.1016 / j.jchromb.2006.04.034 . PMID 16725388 .