Background and overview[1][2]
Ethylene glycol monomethyl ether (abbreviated as MOE), also known as ethylene glycol methyl ether, is a colorless and transparent liquid with a boiling point of 124.6℃ (101.3KPa) and a melting point of -85℃. It can be mixed with water, Miscible with alcohol, acetic acid, acetone and DMF. As an important solvent, MOE is widely used as a solvent for various greases, cellulose acetates, cellulose nitrates, alcohol-soluble dyes and synthetic resins. Quick-drying solvent for enamel and varnish, coating diluent, penetrating agent and leveling agent in the dye industry, also used in printing ink, sealant preparation, and plasticizer manufacturing. In recent years, MOE has been increasingly used in pharmaceuticals. Industry, aviation jet fuel anti-icing agent, brake fluid diluent, etc., the usage is increasing year by year. Derived from the reaction of ethylene oxide and methanol.
Preparation[3-4]
1. Preparation method of chromatographic grade organic solvent ethylene glycol monomethyl ether
CN201110440309.9 provides a method for preparing chromatography-grade organic solvent ethylene glycol monomethyl ether with simple process, stable quality and high product purity. The steps are as follows:
(1) Adsorb the raw material ethylene glycol monomethyl ether through an adsorption column equipped with adsorbent at a flow rate of 30mL-100mL/min;
(2) Add the ethylene glycol monomethyl ether effluent after adsorption in step (1) with 0.1% weight ratio of 2,4 dinitrophenylhydrazine, stir for 1h to 2h, and then dry with a desiccant. Column, the moisture content after drying is controlled at ≤0.05%;
(3) Pour the dried ethylene glycol monomethyl ether in step (2) into a rectification kettle for rectification. Add calcium hydride to the kettle in an amount of 0.1 of the weight ratio of ethylene glycol monomethyl ether. -0.3%, the bottom temperature of the distillation kettle is 180~300℃, the liquid temperature in the kettle is 130℃~150℃, the temperature at the top of the kettle is 124℃, the reflux ratio is controlled to 10:2~8, the reflux time is 2~4 hours, precise After distillation, filter through a microporous membrane, and the filtrate is chromatography grade ethylene glycol monomethyl ether.
2. A method for recovering ethylene glycol monomethyl ether
CN201510126964.5 provides a method for recovering ethylene glycol monomethyl ether from ethylene glycol monomethyl ether industrial wastewater with high moisture content, which is characterized by first using a salting-out and layering method to recover ethylene glycol monomethyl ether from water with a moisture content of ≥40%. (mass percentage) ethylene glycol monomethyl ether industrial wastewater is recovered to obtain an organic phase of an ethylene glycol monomethyl ether solution with a moisture content of <20%. The organic phase is dehydrated through azeotropic distillation or desiccant, and then A method to obtain the finished product of ethylene glycol monomethyl ether with a moisture content of ≤0.2% after distillation.
The specific operation steps are as follows: Add a certain amount of salt potassium fluoride or phosphoric acid to industrial wastewater with a moisture content of ≥40% (mass percentage) and an ethylene glycol monomethyl ether mass concentration of 5 to 60%. Potassium is salted out and stratified. The amount of salt is 20% to 100% (mass percentage concentration) of the total weight of industrial wastewater, so that the industrial wastewater is divided into two phases, and the upper layer is the organic phase of ethylene glycol monomethyl ether solution. The moisture content of the organic phase is <20%. The lower layer contains salty wastewater, which enters the factory wastewater treatment system.
The organic phase of the ethylene glycol monomethyl ether solution obtained by the salting-out and layering treatment is subjected to azeotropic distillation or dehydration with a desiccant, and then is rectified to obtain the finished product of ethylene glycol monomethyl ether. The moisture content of the obtained ethylene glycol monomethyl ether finished product is ≤0.2%, and the recovery rate is >80%. The entraining agent used for distillation and azeotropic water separation is benzene or toluene, cyclohexane, and isopropyl acetate; the dehydrating agent used for desiccant dehydration is anhydrous calcium chloride.
The salting out and stratification method of the present invention is combined with the distillation, azeotropic water separation or desiccant dehydration method to realize the method of recovering ethylene glycol monomethyl ether from industrial wastewater at low cost, especially from high moisture content. Ethylene glycol monomethyl ether is recovered from industrial wastewater. It has the characteristics of low cost, flexible and easy operation, and is not subject to fluctuations in the composition of industrial raw wastewater. It has broad application prospects.
Application [2] [5]
1. Preparation of ethylene glycol by hydrolysis
Ethylene glycol is an important chemical raw material and strategic material in the country. It is used to manufacture polyester (which can further produce polyester, PET bottles, and films), explosives, glyoxal, and can be used as antifreeze, plasticizer, hydraulic Fluids and solvents, etc. CN201510644148.3 provides a new process for producing ethylene glycol by hydrolyzing ethylene glycol monomethyl ether.
The method includes: passing fresh raw materials ethylene glycol monomethyl ether and water through a reaction zone carrying a solid acid catalyst and reacting under the following reaction conditions.The mixture of �� is separated by a separation system to obtain ethylene glycol as the target product, methanol, dimethyl ether and ethylene glycol derivatives as by-products, as well as unreacted raw materials ethylene glycol monomethyl ether and water; make The target product ethylene glycol enters the product collection system, and the methanol and dimethyl ether in the by-products enter the by-product collection system, and the ethylene glycol derivatives in the by-products and unreacted raw material ethylene are Glycol monomethyl ether and water circulate to mix with fresh raw materials ethylene glycol monomethyl ether and water and then enter the reaction zone and react, thereby realizing the hydrolysis of ethylene glycol monomethyl ether to prepare ethylene glycol.
2. Preparation of ethylene glycol methyl ether acetate
CN200810033877.5 provides a method for preparing ethylene glycol methyl ether acetate by transesterification with high product yield, fast reaction rate and low energy consumption. During the synthesis process, an organic titanium compound is used as a catalyst, and the reaction ends Afterwards, ethylene glycol methyl ether acetate can be obtained by direct distillation treatment, and the reaction yield reaches more than 95%.
The molecule of glycol ether acetate has both ether bond and carbonyl group, and the carbonyl group forms the structure of ester. Therefore, it has properties that general organic solvents do not have. It can dissolve organic molecules, synthetic or It is a natural polymer compound that can be miscible with water or water-soluble compounds to varying degrees. It is an excellent high-boiling point bifunctional low-toxic advanced industrial solvent. Its performance is better than glycol ether. It is used in automobile paints, containers, machinery It is widely used in the production of equipment, metal furniture, appliance surface coatings, inks, water-soluble coatings, colorful spray coatings, as well as paint removers, industrial cleaning agents, wood stains and other products.
A method for preparing ethylene glycol methyl ether acetate, which includes the following specific steps:
Step 1 Transesterification Reaction
Put ethyl acetate and ethylene glycol methyl ether into a three-neck container equipped with electromagnetic stirring, a thermometer, a distillation column, a receiving tube, and a recovery flask. The molar ratio is 1 to 8:1. Add 1% of the total raw materials. An organic titanium compound weighing 0.1 to 1% is used as a catalyst, and is heated and refluxed with stirring. The heating temperature is controlled at 70 to 120°C, so that the ethanol produced by the reaction is azeotropically evaporated from the top of the distillation head until the temperature of the top of the distillation head is higher than that of ethyl acetate. The azeotropic temperature of ester and ethanol (that is, no ethanol evaporates) stops;
Purification of the product in step 2
Carry out normal pressure distillation of the material obtained in the previous step, collect the fractions at 140-145°C, and obtain a colorless and transparent product, which is ethylene glycol methyl ether acetate. The organic titanium compound is n-butyl titanate or isopropyl titanate. Compared with the existing technology, the advantages of the present invention are: (1) high yield, 95.5-99.6%; (2) high catalyst activity, small catalyst dosage, accounting for about 0.1-1% of the total weight of reaction raw materials; (2) 3) The reaction conditions are mild and the reaction occurs under normal pressure; (4) The equipment has little corrosion and no environmental pollution.
Main reference materials
[1] Concise Dictionary of Fine Chemicals
[2] CN201510644148.3 A method for preparing ethylene glycol by hydrolyzing ethylene glycol monomethyl ether
[3] CN201110440309.9 Preparation method of chromatography-grade organic solvent ethylene glycol monomethyl ether
[4] CN201510126964.5 A recovery method of ethylene glycol monomethyl ether
[5]CN200810033877.5 Preparation method of ethylene glycol methyl ether acetate
