Background and overview[1]
Diethylene glycol dimethyl ether is also called diglyme and bis(2-methoxyethyl) ether. Colorless transparent liquid. Relative molecular mass 134.18. Relative density 0.9451 (20/20℃). Melting point -68℃. Boiling point: 162°C, 116°C (26.664×103Pa), 75°C (3.333×103Pa), 20°C (0.×103Pa). Flash point 70℃. Refractive index 1.4097. Miscible with water, alcohol, ether and hydrocarbon solvents. Diglyme is an aprotic strong polar solvent and is widely used as a solvent for the synthesis of organometallic compounds, alkylation reactions, and polycondensation reactions; as a raw material for medicine and organic synthesis. Diethylene glycol dimethyl ether can be produced by reacting diethylene glycol with methanol.
Application[2-3]
Diglyme has been widely used as a solvent in coatings, pharmaceuticals, pesticides and other industries. Examples of its applications are as follows:
1) Prepare a metal shell surface cleaning agent material composition and cleaning agent, wherein the composition includes water, sodium thiosulfate, polyethylene glycol octylphenyl ether, sodium pyrophosphate, diglycerol Dimethyl glycol, sodium tetraborate and sodium bicarbonate; wherein, relative to 1000 parts by weight of the water, the content of the sodium thiosulfate is 5-30 parts by weight, and the polyethylene glycol octylphenyl The content of ether is 3-20 parts by weight, the content of sodium pyrophosphate is 5-20 parts by weight, the content of diglyme is 3-10 parts by weight, and the content of sodium tetraborate is 10 -20 parts by weight, the content of sodium bicarbonate is 20-40 parts by weight. Through the above design, the effect of effectively removing rust on metal surfaces, making cleaning easy, and saving time and effort is achieved.
2) Preparing 2-bromoanthracene, including the following steps: a) Add aluminum chloride solid to diglyme to form the first solution. During the preparation process, control the temperature at 30-70°C, and the preparation is completed. Cool to 20~40°C; b) Mix 2-bromoanthraquinone, potassium borohydride and diglyme and raise the temperature to 80~120°C, keep it warm for 0.5~5h, and then add the first solution dropwise to maintain the stability of the system The temperature is at 90-130°C to obtain the second solution; c) Cool the second solution to 90-120°C, then pour it into the hydrochloric acid aqueous solution for hydrolysis, and control the hydrolysis temperature at 20-60°C. After hydrolysis, cool down. Perform suction filtration to obtain the crude product; d) Add absolute ethanol to the crude product, raise the temperature to 50-70°C and keep it for 0.5-3.0 hours, then lower the temperature to 10-40°C, and obtain 2-bromoanthracene fine product by suction filtration. The invention has the following beneficial effects: simple synthesis, convenient post-processing, suitable for industrial production, and has great reference significance and high commercial value in the preparation of halogenated anthracene.
Preparation[4]
The synthesis route is: using diethylene glycol as the starting material, chlorination reaction occurs with thionyl chloride to generate 2,2′-dichlorodiethyl ether, and 2,2′-dichlorodiethyl ether is then reacted with sodium methoxide Through Williamoso reaction, the target product diglyme is obtained, and its reaction formula is:
1) Preparation of 2,2′-dichlorodiethyl ether (bis(2-chloroethyl) ether)
Method 1: In a 1L three-necked flask, put 63.7g (0.6mol) diethylene glycol, ml benzene and 102.8g (1.3mol) pyridine ① 1996-08-09 Received Press Release, shake to mix evenly. A thermometer, reflux condenser and dropping funnel were installed on the mouth of the bottle. The entire flask was placed on an electromagnetic stirrer with a water bath. Start stirring, heat the water bath with the electric heating tube, and add 94.5ml ( 155g, 1.3mol) thionyl chloride. Then stir and reflux for 12 hours. Use hydrochloric acid to adjust the pH of the reaction mixture to about 2 so that all the solids formed are dissolved. Separate the organic layer and dry it with anhydrous sodium sulfate. Filter to remove the desiccant. , after distilling the solvent benzene under normal pressure, the product was distilled under reduced pressure, and the 68-72°C (2.66kPa) fraction was collected to obtain 75.8g of product, with a yield of: 88.2%.
Method 2: Add 53g (0.5mol) diethylene glycol into a 500ml four-necked flask, cool to 0~2°C, add 80ml (129g, 1.1mol) of thionyl chloride dropwise under stirring, and control the temperature of the dropwise addition Below 20°C. A large amount of irritating gas will be generated during the dripping. Use an air guide tube to introduce it into the water tank. After the dripping is completed, stir the reaction at room temperature for 3 hours and let it stand overnight. The next day, slowly add pyridine while stirring. A large amount of solid precipitates in the system. Heat, stir and reflux for 3 hours. Cool the reaction solution, then pour it into cold water, extract the mixture several times with CHCl3, combine the organic layers, and dry over anhydrous sodium sulfate. Filter to remove the desiccant, and distill under normal pressure. After the solvent chloroform is removed, the product is distilled under reduced pressure, and the 68-72°C (2.66kPa) fraction is collected to obtain 42.9g of product, with a yield of 60%.
2) Preparation of diglyme
Method A: Add 320ml (256g, 8mol) methanol into a 500ml round-bottom flask, install a reflux condenser and a calcium chloride drying tube, and slowly add 25g (1.09mol) metal sodium chips to prepare a sodium methoxide solution .Later, 69g (0.48mol) of 2,2′-dichlorodiethyl ether was added dropwise, stirred electromagnetically, and heated to reflux for 40h. After the reaction, filter out a large amount of NaCl solid by-products produced by the reaction, and then distill away the methanol under normal pressure. Then distill under reduced pressure to collect the 52-65°C (2.66kPa) fraction. Finally, the collected fractions are distilled under normal pressure, and the 152-154°C (8.13kPa) fraction is collected. 51g of product is obtained, and the yield is: 79.3%.
Method B: Add 320ml (256g, 8mol) methanol into a 500ml three-necked flask, then add 40g (1mol) solid sodium hydroxide, stir, and heat in a water bath. Then add 57.2g (0.4mol) 2,2′- dropwise After adding dichlorodiethyl ether, stir and react at 40°C for 80h. Then stir and react at 120°C for 20h. After the reaction is completed, follow the same post-processing as “Method A” to obtain 37g of product, with a yield of 69%.
Main reference materials
[1] Practical Fine Chemical Dictionary
[2] CN201510972085.4 Metal shell surface cleaning agent material composition and preparation method of cleaning agent
[3] CN201710073470.4 A preparation method of 2-bromoanthracene
[4] Research on the synthesis of diglyme
