Preparation and purification method and application of triethyl phosphate

Background and overview

Triethyl phosphate is a colorless and transparent liquid, easily soluble in ethanol, soluble in organic solvents such as ether and benzene, and also soluble in water. Very wide range of uses, e.g. as auxiliaries in textiles and paper products, as plasticizers in plastics and coatings, non-reactive flame retardants, hardeners and accelerators, lubricants, flotation agents, defoamers , emulsifier, stabilizer or extractant.

Preparation and purification process

In a 2L three-necked flask, add anhydrous ethanol (368.56g, 8mol), then add acetone (92.9g, 1.6mol), stir and mix and cool to below 10°C, and control the temperature of the mixture to not higher than 10°C Under the conditions, phosphorus oxychloride (245.33 g, 1.6 mol) was added in batches, and the feeding time was 50 minutes. After the feeding is completed, stir for 10 minutes, heat to 30 degrees under vacuum conditions, vacuum degree 10mmHg, react for 3 hours, add sodium alkoxide solution containing 12.5g ethanol after the reaction, stir for 1 hour, cool and dissolve in water to generate sodium chloride , the organic phase was separated and collected, the organic phase was washed to neutrality, and water, low-boiling ethanol and acetone were removed by distillation under reduced pressure to obtain a triethyl phosphate product with a purity of not less than 96%, and the crude product weighed 292.4 g.

Mix the crude triethyl phosphate and the antioxidant di-tert-butyl hydroquinone evenly in the storage tank. Negative pressure distillation was carried out at 80°C. The rectification tower has 28-32 theoretical plates, adopts JW-700 stainless steel wire mesh corrugated packing, the system vacuum degree is 6-8mm Hg, the reboiler temperature of the control tower is 102-108℃, and the reflux ratio is 16-18:1. The extraction temperature at the top of the tower is 52-55 °C, and the diethyl phosphate by-product is continuously extracted, and the semi-finished product of triethyl phosphate is extracted from the tower bottom, which is continuously pumped into the product rectification tower with a metering pump for negative pressure rectification. The product distillation column has 32-36 theoretical plates, using JW-700 stainless steel wire mesh corrugated packing, the system vacuum degree is 6-8mm Hg, the reboiler temperature of the control tower is 118-124 ℃, and the reflux ratio is 3-4:1 , the extraction temperature at the top of the tower is controlled at 64-68 °C, and the triethyl phosphate product is continuously extracted. After stable operation, the distillation yield was 96.1%, the product purity of triethyl phosphate was 99.87%, and the acid value was 0.015mg KOH/100g.

Use

Catalyst: xylene isomer catalyst; olefin polymerization catalyst; catalyst for producing tetraethyl lead; catalyst for producing carbodiimide; catalyst for displacement reaction between trialkylboron and olefin; catalyst for producing ketene by high temperature dehydration with acetic acid ; Catalyst for the polymerization of styrene and conjugated diene compounds; if used in the polymerization of terephthalic acid and ethylene glycol, it can prevent fiber discoloration.

Solvents: Solvents for nitrocellulose and cellulose acetate; solvents for maintaining the life of organic peroxide catalysts; solvents for dispersing fluorinated ethylene; peroxide agents and diluents for curing catalysts for polyester resins and epoxy resins agent.

Stabilizers: chlorine-based insecticides and stabilizers; stabilizers for phenolic resins; solid agents for sugar alcohol resins.

Synthetic resin: curing agent of xylenol formaldehyde resin; softener of phenolic resin used in shell molds; softener of vinyl chloride; plasticizer of vinyl acetate polymer; flame retardant of polyester resin.

Triethyl phosphate (flame retardant TEP) is a high boiling point solvent, a plasticizer for rubber and plastics, and is also used as a raw material for the preparation of pesticides and pesticides, and is used as an ethylating agent and ketene production.

References

【1】CN105859770,2016, A

【2】CN 104447855 A

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