Method for synthesizing 3,3'-dimethyl-4,4'-diamidodiphenylmethane
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A technology of diaminodiphenylmethane and dimethyl, applied in the field of organic monomer synthesis, can solve problems such as unsatisfactory product purity, reduced yield, multiple recrystallizations, etc. mild conditions
Inactive Publication Date: 2011-11-23
LANZHOU JIAOTONG UNIV
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Then recrystallization must be repeated many times, which will reduce the yield. If the product with high yield is to be obtained, the product purity is not ideal
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Embodiment 1
[0032] A method for synthesizing 3,3'-dimethyl-4,4'-diaminodiphenylmethane, comprising the following process steps:
[0033] a. In a four-necked flask equipped with a stirrer and a thermometer, add 10.7g o-toluidine, and protect it with nitrogen;
[0034] b. 36.5% of 12 g hydrochloric acid was diluted to 50ml with distilled water, the diluted hydrochloric acid was 7.3%, poured into the dropping funnel, added dropwise at a temperature of 15°C, and the dropping time was 0.5 h;
[0035] c. Add 4.06g of formaldehyde with a concentration of 37% dropwise within 0.5h, and react at the same temperature for 1h; then gradually raise the temperature to 55°C within 1.5h, and react for 1h; gradually raise the temperature to 72°C within 0.5h, and react for 2h ;
[0036] d. After the reaction is over, when the temperature is naturally lowered to 35°C, add excess ammonia water dropwise until the pH of the solution is 7, then add potassium hydroxide to adjust the pH of the solution to 9, filt...
Embodiment 2
[0039] A method for synthesizing 3,3'-dimethyl-4,4'-diaminodiphenylmethane, comprising the following process steps:
[0040] a. In a four-necked flask equipped with a stirrer and a thermometer, add 10.7g o-toluidine, and protect with nitrogen;
[0041] b. Dilute 15 g hydrochloric acid of 36.5% to 70ml with distilled water, after dilution, the hydrochloric acid is 6.5%, pour it into the dropping funnel, add dropwise at a temperature of 30°C, and the adding time is 1.5 h;
[0042] c. Add 5.27g of formaldehyde with a concentration of 37% dropwise within 1.5h, and react at the same temperature for 1.5h; then gradually raise the temperature to 60°C within 1h, and react for 1.5h; gradually raise the temperature to 74°C within 0.5h, and react for 3h ;
[0043] d. After the reaction is completed, when the temperature is naturally lowered to 35°C, add excess ammonia water dropwise until the pH of the solution is 8, then add potassium hydroxide to adjust the pH of the solution to 9.5, ...
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Abstract
The invention provides a novel environmentally-friendly method for synthesizing 3,3'-dimethyl-4,4'-diamidodiphenylmethane (2MMDA1). The method comprises the following steps: by taking o-toluidine, hydrochloric acid and formaldehyde as raw materials, carrying out condensation reaction on the raw materials in the presence of no catalyst so as to obtain the hydrochloride of 2MMDA1; and then filtering, washing, drying and recrystallizing so as to obtain a target product, wherein sewage generated in the process is regulated by using diluted phosphoric acid so that the pH reaches about 7.0, the sewage is subjected to standing and precipitation, and supernate is taken for later use. The yield of 2MMDA1 is 75-85%, and the purity of 2MMDA1 is 95%. Relative to reported processes, the method provided by the invention has the advantages that: (1) the catalyst is not introduced in the reaction process, and sewage generated in the process and secondary pollution of solvent used for recrystallization can be avoided; and (2) ammonia water, potassium hydroxide and phosphoric acid are used as neutralization reagents, the finally generated sewage is rich in NH<4+>, k<+> and PO4<3-> ions which are necessary for plant growth; and the sewage after dilution can be directly used for irrigating a tree farm and a grass land, thereby achieving the harmless utilization of the sewage.
Description
technical field [0001] The invention relates to the technical field of synthesis of organic monomers, in particular to a method for synthesizing 3,3'-dimethyl-4,4'-diaminodiphenylmethane. Background technique [0002] 3,3'-Dimethyl-4,4'-diaminodiphenylmethane (2MMDA1 for short) is white or off-white frond or needle (mainly depends on the solvent used in refining), mainly used as a ring Adhesive agent and curing agent for oxygen resin and polyurethane resin. It is characterized by heat resistance, chemical resistance, and excellent electrical properties. 2MMDA1 is synthesized with maleic anhydride, and then prepolymerized with diamine to obtain polyimide resin, and 2MMDA1 is condensed with pyromellitic dianhydride to obtain polyimide resin. Products processed with the above materials have excellent heat resistance, insulation performance and stability to solvents, so they are mostly used in high-temperature varnishes, capacitor films, printed circuit boards and aviation part...
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