Piperazine-containing phosphorus-nitrogen type halogen-free flame retardant, and preparation method and use thereof

[0037] Example 1:

[0038] A preparation method of a piperazine-containing cyclic phosphorus nitrogen-based halogen-free flame retardant, comprising the following steps:

[0039] 1) 500mL solvent dichloromethane, 3mol acid binding agent triethylamine and 1.0mol intermediate 2-thio-2-chloro-5,5-dimethyl-1,3,2-dioxygen were added to the reaction vessel Phosphatane, at 0°C, a solution of 1.0mol N-methylpiperazine / 100mL solvent dichloromethane was added dropwise to the reaction vessel;

[0040] The reaction vessel is: a 1L three-necked flask equipped with a stirrer and a reflux condenser;

[0041] 2) After the dropwise addition was completed, the reaction was continued for 24 hours at room temperature (25°C);

[0042] 3) After the reaction is completed, filter, add 150 mL of distilled water to the mother liquor, extract three times with 200 mL of dichloromethane extract, collect the organic phase, and dry; remove the extractant to obtain a crude product;

[0043] 4) The crude pr

[0044] Example 2:

[0045] A preparation method of a piperazine-containing cyclic phosphorus nitrogen-based halogen-free flame retardant, comprising the following steps:

[0046]1) 500mL solvent 1,2-dichloroethane, 4mol acid binding agent triethylamine, 1.0mol methylpiperazine and 75mmol catalyst 4-dimethylaminopyridine were added to the reaction vessel, and the intermediate The body solution was added dropwise to the reaction vessel; the intermediate solution was composed of 1.0 mol of the intermediate 2-thio-2-chloro-5,5-dimethyl-1,3,2-dioxaphosphine alkane and 200mL solvent 1,2-dichloroethane;

[0047] The reaction vessel is: a 1L three-necked flask equipped with a stirrer and a reflux condenser;

[0048] 2) After the dropwise addition was completed, the reaction was continued for 4 hours at 80°C;

[0049] 3) After the reaction is completed, filter, add 150 mL of distilled water to the mother liquor, extract three times with 200 mL of dichloromethane extract, collect the or

[0051] Example 3:

[0052] A preparation method of a piperazine-containing cyclic phosphorus nitrogen-based halogen-free flame retardant, comprising the following steps:

[0053] 1) add 500mL solvent toluene, 2mol acid binding agent triethylamine, 1.0mol methylpiperazine and 75mmol catalyst 4-dimethylaminopyridine in reaction vessel, under 0 ℃ of conditions, the intermediate solution is in the mode of dropping Add the reaction vessel; the intermediate solution consists of 1.0 mol of the intermediate 2-thio-2-chloro-5,5-dimethyl-1,3,2-dioxaphosphine and 200 mL of solvent toluene;

[0054] The reaction vessel is: a 1L three-necked flask equipped with a stirrer and a reflux condenser;

[0055] 2) After the dropwise addition was completed, the reaction was continued for 6 hours at 50°C;

[0056] 3) After the reaction is completed, filter, add 150 mL of distilled water to the mother liquor, extract three times with 200 mL of dichloromethane extract, collect the organic phase, and dr