Bis (2-methoxyethyl) ether

Structural formula
General
Surname	Bis (2-methoxyethyl) ether
other names	Diglyme Diglycol dimethyl ether Diglycol dimethyl ether Diethylene glycol dimethyl ether Diethylene glycol dimethyl ether DEGDME
Molecular formula	C 6 H 14 O 3
Brief description	colorless liquid
External identifiers / databases
CAS number 111-96-6 EC number 203-924-4 ECHA InfoCard 100.003.568 PubChem 8150 ChemSpider 13839575 DrugBank DB02935 Wikidata Q865952
properties
Molar mass	134.18 g mol −1
Physical state	liquid
density	0.94 g cm −3
Melting point	−64 ° C
boiling point	160 ° C
Vapor pressure	2.24 h Pa (20 ° C) 4.27 hPa (30 ° C) 7.77 hPa (40 ° C) 13.6 hPa (50 ° C)
solubility	miscible with water
Refractive index	1.4097 (20 ° C)
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 226-360FD EUH: 019 P: 201-210-308 + 313
Authorization procedure under REACH	of particular concern : toxic for reproduction ( CMR ); subject to approval
MAK	DFG : 5 ml m −3 or 28 mg m −3 Switzerland: 5 ml m −3 or 27 mg m −3
Toxicological data	5400 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

Bis (2-methoxyethyl) ether , often referred to as diglyme (of Digly Coldi me dimethyl ether for short), is a high-boiling organic solvents . It is an ether of diethylene glycol .

Presentation and extraction

Diglyme is produced through a catalytic conversion of ethylene oxide with dimethyl ether . Another possible synthesis is the Williamson reaction of diethylene glycol monomethyl ether with methyl chloride .

properties

Physical Properties

Diglyme is a clear, colorless liquid that boils at 162 ° C under normal pressure . The heat of vaporization is 45.4 kJ mol ⁻¹ . According to Antoine, the vapor pressure function results from log ₁₀ (P) = A− (B / (T + C)) (P in bar, T in K) with A = 4.87223, B = 1922.137 and C = −38.063 in the temperature range from 286 to 433 K. The melting point is −64 ° C, where the heat of fusion is 17.78 kJ · mol ⁻¹ . The heat capacity at 25 ° C is 279.84 J mol ⁻¹ K ⁻¹ or 2.08 J g ⁻¹ K ⁻¹ . The compound is miscible with water, alcohols and diethyl ether .

Chemical properties

The compound tends to form peroxide in the presence of air or oxygen. Slow decomposition occurs at temperatures above 150 ° C.

Safety-related parameters

Diglyme forms flammable vapor-air mixtures. The compound has a flash point of 51 ° C. The explosion range is between 1.3% by volume (72 g / m³) as the lower explosion limit (LEL) and 17.4% by volume as the upper explosion limit (UEL). A correlation of the explosion limits with the vapor pressure function results in a lower explosion point of 50 ° C. The ignition temperature is 190 ° C. The substance therefore falls into temperature class T4.

use

A lithium cation chelated by diglyme

Diglyme is mainly used as a solvent in organic reactions to chelate small cations so that the anions become more reactive. As a result, for example, Grignard reactions can be carried out more quickly and more effectively. It also serves as an azeotrope distillation agent or entrainer and is found in diesel fuels.

Restrictions

In 2014 diglyme was added to the SVHC list of the European Chemicals Agency ECHA. As a result, its use within the European Union is subject to an authorization procedure by the European Commission according to the REACH regulation .

Individual evidence

1. ↑ ^{a b c d e f g h i j k l m n o p q r} Entry on diglycol dimethyl ether in the GESTIS substance database of the IFA , accessed on May 22, 2020(JavaScript required) .
2. ↑ 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. 3-168.
3. ↑ Entry on bis (2-methoxyethyl) ether 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 .
4. ↑ Entry in the SVHC list of the European Chemicals Agency , accessed on September 25, 2014.
5. ↑ Entry in the register of substances subject to authorization of the European Chemicals Agency , accessed on September 25, 2014.
6. ↑ Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values (search for 111-96-6 or bis (2-methoxyethyl) ether ), accessed on November 2, 2015.
7. ↑ ^{a b} Entry on diethylene glycol dimethyl ether. In: Römpp Online . Georg Thieme Verlag, accessed on May 23, 2020.
8. ↑ Wallace, WJ; Mathews, AL: Density, Refractive Indices, Molar Refractions, and Viscosities of Diethylene Glycol Dimethyl Ether-Water Solutions at 25 C in J. Chem. Eng. Data 9 (1964) 267-268.
9. ↑ Li, Dan; Fang, Wenjun; Xie, Wenjie; Xing, Yan; Guo, Yongsheng; Lin, Ruisen: Measurements on Vapor Pressure and Thermal Conductivity for Pseudo-binary Systems of a Hydrocarbon Fuel with Ethylene and Diethylene Glycol Dimethyl Ethers in Energy & Fuels 23 (2009) 794-798, doi : 10.1021 / ef8007163 .
10. ^ Stull, DR: Vapor Pressure of Pure Substances. Organic and Inorganic Compounds in Ind. Eng. Chem. 39 (1947) 517-540, doi : 10.1021 / ie50448a022 .
11. ↑ Domalski, ES; Hearing, ED: Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III in J. Phys. Chem. Ref. Data 25 (1996) 1-525, doi : 10.1063 / 1.555985 .
12. ↑ Villamanan, MA; Casanova, C .; Roux-Desgranges, G .; Grolier, J.-PE: Thermochemical behavior of mixtures of n-alcohol + aliphatic ether: heat capacities and volumes at 298.15 K in Thermochim. Acta 52 (1982) 279-283.
13. ^ Chemical & Engineering News . Vol. 92, no. 35, September 1, 2014, p. 38.