Overview[1]
Using hydroquinone as raw material to synthesize paraphenylene dimethyl ether, based on different alkylating agents including dimethyl carbonate method, dimethyl sulfate method, diazomethane method, halogenated methane method and certain inorganic acids Methyl ester method, etc. Dimethyl sulfate is a commonly used alkylating agent, and its reaction conditions are mild. However, dimethyl sulfate is a highly toxic substance that is inconvenient to transport, use, and manage. Only one methyl group participates in the reaction, and the utilization rate is low. Large amounts of wastewater are difficult to treat. Diazomethane reacts easily with acids but is difficult to react with phenol. Methyl iodide in alkyl halides is a classic alkylating agent with high reaction yield, but it is expensive and not suitable for large-scale use. The reactivity of methyl chloride is weaker than that of iodine. Methane is much cheaper, has low toxicity, and produces less wastewater during the reaction. If a higher reaction yield can be achieved, using methyl chloride to synthesize terephthalene is a good choice.
Application[1,3-4]
Paralylene dimethyl ether is a relatively common organic synthetic raw material. It is often used in the synthesis and preparation of spices, daily chemicals, food, tobacco flavors, etc. It can also be used as an anti-corrosion agent for plastics and paints. It is used in the synthesis of some dyes and pharmaceutical intermediates, such as the synthesis of 2,5-dimethoxyaniline, 2,5-dimethoxyacetophenone, dye black salt ANS, etc.
1) Synthesis of methoxyamine hydrochloride, using DL-α-alanine as raw material, methanol as solvent, and the action of triethylamine to obtain N-trifluoroacetyl-DL-α-alanine ; Then react it with terephthalyl ether, using dichloromethane as the solvent and oxalyl chloride as the acylating agent to obtain 2-trifluoroacetyl-1-(2,5-dimethoxyphenyl)-1 -Acetone, and then under the action of hydrochloric acid, using ethanol as the solvent, deprotection group to obtain 2-amino-1-(2,5-dimethoxyphenyl)-1-propanone hydrochloride, and finally in potassium borohydride Under the action of , the crude methoxamine hydrochloride is obtained by reduction, and ethanol is used as the refining solvent to obtain a refined methoxamine hydrochloride with a purity of 99.9%, a single impurity of less than 0.05%, and a total impurity of less than 0.1%. The preparation method of the present invention has cheap and easy-to-obtain raw materials, easy operation, high purity of the prepared product, high yield and lower cost, and is very suitable for large-scale production.
2) Preparing the surface film layer for built-in sunshade safety insulating glass, involving the fields of glass deep processing and photovoltaic glass, including the following steps: built-in sunshade safety insulating glass film, consisting of precursor, solvent, catalyst, surfactant, silane The coupling agent composition, in terms of mass percentage, is as follows: 20% paraphenylene ether, 35% isopropyl alcohol, 6% soda water, antipyretic ice + hydrofluoric acid 0.16%, cetyltrimethylammonium bromide 0.8%, KH450+KH56312%, 3-dimethylbutanamide 6%, leveling agent 0.3%. The present invention forms mesopores on the surface of the silica particles through the pore-forming effect of the surfactant on the surface of the silica particles. This not only ensures the density of the film layer, but also improves the porosity and improves the optical properties of the film layer. In order to optimize the built-in sunshade safety insulated glass film, the film layer has high hardness and high structural density, which makes it have good weather resistance, wear resistance, UV resistance, etc. The production process of the built-in sunshade safety insulated glass film is simple and easy to control. More suitable for industrial production.
Preparation[1-2]
Method 1: Use methyl chloride as the methylation reagent and hydroquinone as the reaction substrate to synthesize terephthalene:
1) Preparation of hydroquinone disodium salt
In a 1000mL four-neck round-bottomed flask equipped with a stirring device, a thermometer, and a constant-pressure dropping funnel, add 110g (1.0mol) hydroquinone and 150g water respectively. Stir to dissolve and cool to 10℃, slowly add 331g sodium hydroxide solution [96g (2.4mol) sodium hydroxide, 235g water] dropwise, keep the temperature below 25℃, complete the addition in about 0.5h, and then continue below 25℃ Stir the reaction for 15 minutes and set aside the reaction solution.
2) Preparation of paraphenylene dimethyl ether
Transfer the above reaction solution into a high-pressure reaction kettle, stir, add 141.4g (2.8mol) of methyl chloride, raise the temperature to 90°C, and continue to keep it warm for 5 hours. After the reaction is completed, cool to normal temperature, take out the material and filter, and the filter cake is Crude dimethyl ether. Wash the crude product twice with water, then transfer it to a four-necked flask for steamingDistill and collect the fractions. When no white solid precipitates in the distillate, it indicates that the product terephthalene has completely evaporated with water vapor. After the steam distillation is completed, the collected fractions are filtered. The filter cake is the product paraphenylene ether. After drying, the content is 99.5% by gas chromatography, and the yield is 87.8%.
Method 2: A synthesis method of paraphenylene dimethyl ether, which specifically includes the following steps: add 45g hydroquinone to a 500mL four-neck bottle equipped with a thermometer, stirring, reflux condenser and constant pressure dropping funnel , 45g sodium hydroxide, 135g water. Start stirring. After all the raw materials are dissolved, slowly add 67g of dimethyl sulfate into the reaction bottle from the constant pressure dropping funnel. Control the dropping speed so that the internal temperature does not exceed 80°C. After the dropwise addition is completed, turn on the heating and keep the reaction at 95°C for 5 hours. After the reaction is completed, change the reflux condenser into a distillation device and heat it to 120°C to distill and evaporate the water until all the water is evaporated. Then change the rectification device to a distillation device, heat it to 240°C, and distill the product into a collection bottle. The resulting finished product is cooled to 50°C and solidified.
Main reference materials
[1] Research on the synthesis of paraphenylene dimethyl ether
[2] CN201810268650.2 A synthesis method of paraphenylene dimethyl ether
[3] CN201210556952.2 A synthesis method of methoxamine hydrochloride
[4] CN201711049791.7 Surface film layer for built-in sunshade safety insulating glass and preparation method thereof
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