Preparation of tetrahydroxymethylphosphorus urea chloride condensate_industrial additives

Overview^[1]

Tetrahydroxymethylphosphonium chloride urea condensate, also known as the polymer of tetrahydroxymethylphosphine chloride and urea, is formed by the reaction between the hydroxymethyl group in the molecular structure of tetrahydroxymethylphosphonium chloride (THPC) and urea. It is a colorless and transparent liquid that is slightly acidic and easily biodegradable. Tetrahydroxymethylphosphorus urea chloride is a permanent flame retardant in the post-processing of cotton and polyester-cotton fabrics. It is mainly used for flame retardancy, light isolation, mildew prevention and anti-wrinkle of pure cotton and other fabrics. Since formaldehyde is used in the production of this type of flame retardant, the harmful effects of formaldehyde on the human body and the degradation of its derivatives have always attracted people’s attention.

Apply^[3]

Tetrahydroxymethylphosphorus urea chloride is mainly used as a flame retardant for textiles, especially for cotton textiles. It is still effective as a flame retardant after repeated cleaning, and has a soft feel and good tear resistance. Powerful antioxidant 1010 has little loss and is Affect the original excellent properties of the fabric.

Toxicity

Formaldehyde is produced during the decomposition reaction of THPC, and the homologous product tetrahydroxymethylphosphorus urea chloride will also release formaldehyde and other toxic substances to a greater or lesser extent during the production and use process. The acute oral LD50 of formaldehyde in rats is It is 0.3～0.8g/kg. Acute percutaneous irritation of tetrahydroxymethylphosphorus chloride condensate, obvious erythema was observed at the contact site and lasted for 1 week, which may be related to the inhibition of sweat gland secretion by formaldehyde. This suggests that attention should be paid to skin sensitivity caused by the low volatility of formaldehyde on the surface of fabrics in high-temperature and high-humidity seasons.

The Ames test is a test substance that detects whether it has the ability to induce gene mutation at the prokaryotic cell level. It is a rapid detection of the mutagenicity and potential carcinogenicity of chemical substances and is an internationally certified in vitro testing system. Its reaction endpoint is Gene mutation. Formaldehyde is a confirmed carcinogen for humans. The TA102 hand feeling agent strain is sensitive to formaldehyde substances tested. The test of tetrahydroxymethylphosphonium chloride urea condensate with and without the addition of S9 did not show that tetrahydroxymethylphosphonium chloride was tested. Urea shrinkage has mutagenic effects.

Preparation^[2]

Method 1:

Five minutes after the sodium hypophosphite reaction kettle is fed, phosphine gas is continuously generated in the kettle. The pressure of the gas in the kettle is used to transport phosphine directly to the gas storage tank for collection. Prepare an aqueous solution using formaldehyde and hydrochloric acid at a molar ratio of 4.05:1;

Put the aqueous solution into the absorption tower with a corrosion-resistant pump, spray it downward from the top of the tower, use an air pump to send the phosphine gas in the gas tank into the absorption tower, and carry out the process at a temperature of 50°C. Reaction synthesis to prepare an aqueous solution of tetrahydroxymethylphosphorus chloride;

The reaction formula is as follows:

4HCHO+HCL+PH3＝(HOCH2)4PCL

(4) Perform a synthesis reaction between tetrahydroxymethylphosphonium chloride and urea at a molar ratio of 1.9:1 at a temperature of 70°C to generate tetrahydroxymethylphosphorus urea chloride (THPC-Urea) ), used as a permanent flame retardant for cotton fabrics.

Method 2:

(1) Add hydrochloric acid (30%) and formaldehyde (37%) into reactor 1, and pass the purified exhaust gas containing phosphine (about 80%) generated during the production of sodium hypophosphite through the gas Inlet 3 is added to the gas-liquid circulation mixing reaction pump 2, and phosphine is absorbed through the gas-liquid circulation mixing reaction device at 50-60°C. The phosphine that is not completely absorbed enters the next-level reactor, and formaldehyde is detected by the central control The content determines the end point of the reaction. After the reaction is completed, tetrahydroxymethylphosphorus chloride is obtained by concentrating under reduced pressure; the mass ratio of hydrochloric acid and formaldehyde is 1:3.1-3.2;

(2) Mix the above-mentioned tetrahydroxymethylphosphonium chloride (more than 90%) and urea (nitrogen content ≥ 46.6%) in reactor 1, react at 80-85°C, and obtain the tetrahydroxymethylphosphonium chloride after the reaction is completed Methylphosphorus chloride urea condensate; the mass ratio of tetrahydroxymethylphosphorus chloride and urea is 7.0-7.1:1.

Product indicators: active ingredients 70-72.5, available phosphorus content 10-12%, PH 4.5-5.5, viscosity <50cps, color <100APHA, specific gravity 1.320-1.350g/ml.