Hexahydro-1,3,5-tris(2,3-dibromopropyl)-1,3,5-triazine-2,4,6-trione synthesis

Yield:52434-90-9 99.5%

Reaction Conditions:

with tetraethylammonium bromide;bromine in dichloromethane at 60; for 20 h;Reagent/catalyst;Solvent;Temperature;

Steps:

1.1; 1.2; 1.3; 1.4; 2.1; 2.2; 2.3; 2.4; 3.1; 3.2; 3.3; 3.4; 4.1; 4.2; 4.3; 4.4; 5.1; 5.2; 5.3; 5.4 Example 5

A method for synthesizing a thermally stable TBC flame retardant comprising the following steps:1) 50 g of ≥99.0% of triallyl isocyanurate (TAIC) and 150 g of organic solvent I dichloromethane are added to a 1000 ml reactor according to the ratio.Stir until completely dissolved to prepare an organic solvent reaction system of TAIC;200 g of organic solvent II dichloromethane and quaternary ammonium salt 139 g of tetraethylammonium bromide were added to the 500 ml reactor according to the ratio.Adding 106 g of bromine Br2 dropwise to dissolve all of them to prepare a brominating agent;2) adding the brominating agent prepared in the step 1) to the organic solvent reaction system of TAIC,Raise the temperature to a bromination reaction temperature of 60 ° C, and keep warm for 20 hours until the reaction is complete;The molar ratio of TAIC in the brominating agent in the organic solvent reaction system of bromine Br2 and TAIC was 3.3:1.3) performing the first water washing step 2) after the reaction solution, after removing the water layer,To the organic layer in the reaction liquid in the step 2), a sodium hydrogen sulfite solution having a mass percentage concentration of 20% is added.Until the reaction system reddish brown disappeared;Add an appropriate amount of lye to adjust the pH of the organic layer to neutral.After a second water washing, 200 ml of water was added to the reaction system, and the organic layer was separated and left to stand;The first water washing step 2) after the reaction solution, the water layer is recovered, and the tetraethylammonium bromide is recovered by washing with water, that is, the quaternary ammonium salt in the solution after the step 2) is recovered.As a raw material for the preparation of a brominating agent, the recovery rate is 90% to 98%.4) 1000 ml of water was added to a 2000 ml solvent separation vessel, and the temperature was raised to 62 ° C in the solvent separation vessel.Add appropriate amount of high-purity finished TBC finished product with 20g content ≥98.5% as seed crystal; under vacuum condition, vacuum degree control -0.9Mpa,The organic layer was slowly added dropwise while stirring, and after the completion of the dropwise addition, the mixture was further stirred for 5 hours to precipitate the product as a powder.After precipitation, the product was filtered off and dried to obtain a thermally stable TBC flame retardant product 144.8 g.Using the principle of azeotrope methylene chloride and water azeotrope but not miscible, supplemented by negative pressure,Achieve crystallization separation of products at lower temperatures,The yield was 99.5%, the bromine content was 65.6%, and the melting point was 107-110 °C.5) adding a heat stabilizer 0.5% dibutyltin maleate to the thermally stable TBC flame retardant product prepared in step 4).After mixing, a high thermal stability TBC flame retardant product is obtained.The thermal stability test was performed with a 5% WLT of 280 °C

References:

CN109776438,2019,A Location in patent:Paragraph 0028-0064