Composite phosphorus flame retardant comprising cyclic organophosphate with multiple DOPO moieties and preparation method thereof

A preparation method of a composite phosphorus flame retardant comprising cyclic organophosphate with multiple DOPO moieties, comprising the following steps:

• installing a mechanical agitator, an h-shaped oil-water separator, a reflux condenser pipe, a dropping funnel and a nitrogen gas inlet are installed on a 3 L four-neck flask,
• adding 253.3 g (1.172 mol) of DOPO which is 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 100.6 g of paraxylene, 800 g of 1,1-dual(3,4-dimethyl phenyl)ethane solvents and 64.67 g of butantriol solution to the flask,
• after the paraxylene is added to the oil-water separator fully, heating reaction mixture to 200′C and reacting for 14 hours under protection of nitrogen flow, wherein the oil-water separator continuously discharges water produced in reaction process,
• upon completion of reaction, after system temperature decreases to a room temperature, adding 150 ml of pyridine, and then adding 29.94 g of phosphorus oxychloride with a dropping funnel dropwise, wherein hydrogen chloride gas generated in reaction is neutralized and absorbed by 20% NaOH solutions,
• after the phosphorus oxychloride is added, increasing reaction temperature to 60 T, and then reacting for 2 hours,
• wherein, after reaction mixture is cooled to the room temperature, a product P2 is precipitate out, which is the composite phosphorus flame retardant comprising cyclic organophosphate with multiple DOPO moieties.

A preparation method of a composite phosphorus flame retardant comprising cyclic organophosphate with multiple DOPO moieties, comprising the following steps:

• installing a mechanical agitator, an h-shaped oil-water separator, a reflux condenser pipe, a dropping funnel and a nitrogen gas inlet are installed on a 3 L four-neck flask,
• adding 253.3 g (1.172 mol) of DOPO which is 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 100.6 g of paraxylene, 800 g of 1,1-dual(3,4-dimethyl phenyl)ethane solvents and 56.45 g of a reaction mixture of pentaerythritol and sodium iodide to the flask, wherein 53.13 g of pentaerythritol is dissolved in 160 ml of ethyl alcohol, and 2.55 g of sodium iodide is added to the ethyl alcohol, then mixture is heated for 2 hours, and then the ethyl alcohol is evaporated gradually to obtain the reaction mixture of the pentaerythritol and the sodium iodide,
• after the paraxylene is added to the oil-water separator fully, heating reaction mixture to 200° C. and reacting for 14 hours under protection of nitrogen flow, wherein the oil-water separator continuously discharges water produced in reaction process,
• upon completion of reaction, after system temperature decreases to a room temperature, adding 150 ml of pyridine, and then adding 29.94 g of phosphorus oxychloride with a dropping funnel dropwise, wherein hydrogen chloride gas generated in reaction is neutralized and absorbed by 20% NaOH solutions,
• after the phosphorus oxychloride is added, increasing reaction temperature to 60° C. and then reacting for 2 hours,
• wherein, after reaction mixture is cooled to the room temperature, a product P3 is precipitate out, which is the composite phosphorus flame retardant comprising cyclic organophosphate with multiple DOPO moieties.