Preparation method of triethyl phosphate

Abstract

A preparation method of triethyl phosphate belongs to the field of chemical industry. After phosphorus oxychloride and absolute ethyl alcohol are subjected to low-pressure esterification reaction, excessive absolute ethyl alcohol and partial chlorine hydride are sequentially removed under reduced pressure, residual chlorine hydride is removed under normal pressure and rectification is carried out under reduced pressure to obtain the finished product of triethyl phosphate. With the addition of a catalyst, the temperature of esterification reaction is lowered and the reaction speed is increased, namely, the temperature is lowered to 25 to 35 DEG C from almost 50 DEG C before, and after excessive absolute ethyl alcohol is removed, ammonia is added for neutralization to remove chlorine hydride without water introduction, thus avoiding hydrolyzing triethyl phosphate; and the entire process is simple, high in yield and low in production cost.

Description

technical field [0001] The invention belongs to the field of chemical industry, in particular to a method for preparing triethyl phosphate. Background technique [0002] Triethyl phosphate (TEP for short) is a colorless and transparent liquid chemical product with a high boiling point and good solubility. It is widely used as a solvent, plasticizer and softener in the rubber and plastic industry; it is also prepared from pesticides. It can be used as a stabilizer for pesticides and as a plant growth regulator; in recent years, the country has become more and more strict with fire control requirements, chemical materials, building materials, interior decoration, electronic products, transportation, aerospace communications, etc. All walks of life have higher and higher requirements for flame retardancy. As an efficient flame retardant, triethyl phosphate occupies a place in the flame retardant market due to its good compatibility with substrates. [0003] At present, the pro...

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Problems solved by technology

[0003] At present, the production of triethyl phosphate mainly adopts the process of reacting phosphorus oxychloride and dehydrated alcohol under reduced pressure, such as Chinese patent 021524394 and Chinese patent application 2011100857020, but the following problems generally exist: one, phosphorus oxychloride and ethanol In the later stage of the reaction, the activity of phosphorus oxychloride decreases, and the method of raising the temperature is generally adopted to promote the complete reaction. However, raising the temperature will accelerate the acidolysis or hydrolysis of triethyl phosphate, which is not conducive to the improvement of the yield.

2. There is a small amount of water in the reaction system. Triethyl phosphate is easily hydrolyzed under acidic conditions, especially the molecular weight of water is only less than 1 / 10 of the molecular weight of triethyl phosphate, and the water per unit mass will cause 10 times the damage to the product. even higher destruction

3. Excessive ethanol and hydrogen chloride are degassed and distilled in a multi-stage tower, which requires high equipment and high production costs.

In addition, in the traditional process, after the esterification reaction is completed and the excess ethanol is removed, the mixture is neutralized with an aqueous solution such as sodium carbonate or sodium bicarbonate to remove hydrogen chloride, but the presence of water will make triethyl phosphate Hydrolysis occurs, reducing the yield

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