Method for synthesizing 3,3',5,5'-dimethyl-4,4'-diaminodiphenylmethane

Abstract

The invention provides a new and more environmentally friendly method for synthesizing 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane (4MMDA3). In the present invention, 2,6-xylidine, hydrochloric acid and formaldehyde are used as raw materials to obtain the hydrochloride salt of 4MMDA3 through condensation reaction in the absence of a catalyst, and then filtered, washed and dried, and finally recrystallized with ethanol. Obtain the target product. Adjust the pH of the sewage generated in the process to 7.0-7.1 with dilute phosphoric acid, let it stand for precipitation, and take the supernatant for later use. The yield of 4MMDA3 is 70-78%, and the purity is >97%. Compared with the reported process, this method has the following advantages: (1) no catalyst is introduced in the reaction process, which can avoid the secondary pollution of the sewage generated in the process and the solvent used for recrystallization; (2) the use of ammonia water, potassium hydroxide and phosphoric acid As a neutralizing agent, the final sewage is rich in NH4+, K+, PO43- ions necessary for plant growth. After dilution, this sewage can be directly used to irrigate forest farms and grasslands, which can realize the harmless utilization of 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',5,5'-tetramethyl-4,4'-diaminodiphenylmethane. Background technique

[0002] 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane (referred to as 4MMDA3) is white or off-white fronds or needles (mainly depends on the solvent used in refining) , mainly used as adhesive and curing agents for epoxy resins and polyurethane resins. It is characterized by heat resistance, chemical resistance, and excellent electrical properties. 4MMDA3 is synthesized with maleic anhydride, and then prepolymerized with diamine to obtain polyimide resin, and 4MMDA3 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 ...

Examples

Embodiment 1

[0032] A method for synthesizing 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane,

[0033] a. In a four-necked flask equipped with a stirrer and a thermometer, add 12.1g of 2,6-xylidine, and protect it with nitrogen;

[0034] b. Dilute 12 g hydrochloric acid of 36.5% to 50ml with distilled water. After dilution, the hydrochloric acid is 7.3%, pour it into the dropping funnel, and add it dropwise to the flask at a temperature of 15°C. The time for adding is 0.5 h;

[0035] c. Then add 4.06g of formaldehyde with a concentration of 37% slowly within 0.5 hours, react at the same temperature for 1 hour, then gradually raise the temperature to 55°C within 1 hour, and react for 1 hour; then gradually raise the temperature to 55°C within 1.5 hours 90℃, react for 2h;

[0036] d. After the reaction is completed, after the temperature is lowered to 35°C, excess ammonia water is added dropwise until the pH value of the solution is 7, and potassium hydroxide is added to adjust the pH v...

Embodiment 2

[0039] A method for synthesizing 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane,

[0040] a. In a four-necked flask equipped with a stirrer and a thermometer, add 12.1g of 2,6-xylidine, and protect it 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, and add it dropwise to the flask at a temperature of 30°C. The time for adding is 0.8 h;

[0042] c. Then, 5.27g of formaldehyde with a concentration of 37% was slowly added dropwise within 1.5h, and reacted at the same temperature for 1.5h, then gradually raised the temperature to 65°C within 1.5h, and reacted for 1.5h; then gradually raised the temperature to 94°C within 0.5h. ℃, reaction 2h;

[0043] d .After the reaction is over, cool down 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, filter to ...

technical field

[0001] The invention relates to the technical field of synthesis of organic monomers, in particular to a method for synthesizing 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane. Background technique

[0002] 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane (referred to as 4MMDA3) is white or off-white fronds or needles (mainly depends on the solvent used in refining) , mainly used as adhesive and curing agents for epoxy resins and polyurethane resins. It is characterized by heat resistance, chemical resistance, and excellent electrical properties. 4MMDA3 is synthesized with maleic anhydride, and then prepolymerized with diamine to obtain polyimide resin, and 4MMDA3 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 ...

Examples

Embodiment 1

[0032] A method for synthesizing 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane,

[0033] a. In a four-necked flask equipped with a stirrer and a thermometer, add 12.1g of 2,6-xylidine, and protect it with nitrogen;

[0034] b. Dilute 12 g hydrochloric acid of 36.5% to 50ml with distilled water. After dilution, the hydrochloric acid is 7.3%, pour it into the dropping funnel, and add it dropwise to the flask at a temperature of 15°C. The time for adding is 0.5 h;

[0035] c. Then add 4.06g of formaldehyde with a concentration of 37% slowly within 0.5 hours, react at the same temperature for 1 hour, then gradually raise the temperature to 55°C within 1 hour, and react for 1 hour; then gradually raise the temperature to 55°C within 1.5 hours 90℃, react for 2h;

[0036] d. After the reaction is completed, after the temperature is lowered to 35°C, excess ammonia water is added dropwise until the pH value of the solution is 7, and potassium hydroxide is added to adjust the pH v...

Embodiment 2

[0039] A method for synthesizing 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane,

[0040] a. In a four-necked flask equipped with a stirrer and a thermometer, add 12.1g of 2,6-xylidine, and protect it 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, and add it dropwise to the flask at a temperature of 30°C. The time for adding is 0.8 h;

[0042] c. Then, 5.27g of formaldehyde with a concentration of 37% was slowly added dropwise within 1.5h, and reacted at the same temperature for 1.5h, then gradually raised the temperature to 65°C within 1.5h, and reacted for 1.5h; then gradually raised the temperature to 94°C within 0.5h. ℃, reaction 2h;

[0043] d .After the reaction is over, cool down 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, filter to ...

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