Synthesis method of phosphorus pentachloride

Abstract

The invention discloses a method for synthesizing phosphorus pentachloride. Phosphorus trichloride is injected into a reactor, chlorine gas is passed into the bottom of the reactor through a pipeline, and stirred at a stirring speed of 500 rpm and a pressure of 0.6kpa. Control the reaction temperature to 75-83°C, stop the reaction until no solid matter is generated, and obtain solid phosphorus pentachloride; then put the solid phosphorus pentachloride into a sublimation tank for decompression sublimation; collect the sublimation gas, and carry out Cool and recrystallize to obtain high-purity solid phosphorus pentachloride. Beneficial technical effects of the present invention: the present invention has the advantages of simple preparation, low cost and easy popularization.

Description

technical field [0001] The invention relates to a synthesis method of phosphorus pentachloride, specifically belonging to the technical field of chemical synthesis. Background technique [0002] Phosphorus pentachloride, the molecular formula is PCl5, the molecular weight is 208.24, the pure product is white, and it is light yellow because it is partially decomposed into phosphorus trichloride and chlorine gas after being placed. Generally, the appearance is a white or yellow tetragonal crystal , density 1.60g / cm3, melting point 167°C, soluble in carbon disulfide, carbon tetrachloride and benzoyl chloride, hydrolyzed into phosphoric acid and hydrogen chloride in humid air, producing white smoke and special irritation, sublimation begins when heated to 160°C , and partially decomposed, and all decomposed into chlorine and phosphorus trichloride at 300 °C. Phosphorus pentachloride PCl5 is widely used as chlorinating agent, catalyst, dehydrating agent in organic synthesis, and...

AI Technical Summary

Problems solved by technology

At present, the production of phosphorus pentachloride mostly adopts the traditional production process, using phosphorus trichloride, chlorine gas, etc. as raw materials, first injecting a certain amount of liquid phosphorus trichloride into the stirred reactor, and then feeding chlorine gas, using gas, liquid, etc. Contact mode reaction, the contact area between the reactants in this process is small, the reaction is incomplete, the product yield is low, and the generated phosphorus pentachloride is easy to condense in the reaction kettle to form a hard block, which makes it difficult to discharge the material and the equipment is easy to corrode , damage, and it is difficult to produce high-purity phosphorus pentachloride

In order to overcome the defects in the traditional phosphorus pentachloride production process, the present invention reacts phosphorus trichloride and chlorine gas in a reaction kettle in a gaseous state, which overcomes the small contact area between the reactants in the gas and liquid contact mode of the traditional process, The defect of incomplete reaction and low product yield finally produces phosphorus pentachloride