Process for purifying 1,1,1,3,3-pentafluoropropane

Abstract

The present invention discloses a method for purification of 1, 1, 1, 3, 3-propane pentafluoride. It is characterized in that it can obtain the purified products of 1, 1, 1, 3, 3-propane pentafluoride by effectively separating impurity substances of the crude products such as the trifluorochloropropene, the tetrafluorochloropropene, the tetrafluoropropylene and so on, wherein it adopting a sorbent with a manner of selective adsorption. This invention selects a molecular sieve of A, X, Y, ZSM -5 type treated by alkali metal ion, alkaline-earth metal ion, transient metal ion, rare-earth metal ion and rare-earth metal or a carbon molecular sieve and we can choose any type of the said molecular sieve or we can choose two or more to combine them. The invention is suitable for the industrial production and it can not dramatically decompose the propane pentafluoride while adsorbing the the trifluorochloropropene, the tetrafluorochloropropene and the tetrafluoropropylene with a high select and is friendly to the environment.

Description

technical field [0001] The invention belongs to a purification method of 1,1,1,3,3-pentafluoropropane, in particular a purification method using adsorption separation. Background technique [0002] 1,1,1,3,3-Pentafluoropropane, commercially referred to as R245fa, has an ODP value of 0 and a GWP value of 950. It can replace HCFC-141b as polyurethane and polyisocyanurate foam insulation plastics, Foaming agent for refrigerator freezer industrial insulation materials, building insulation board site and transportation insulation materials. Due to the production process, in addition to the main product R245fa, some by-products inevitably exist in the crude product of R245fa. Fluoropropene (R1224) and tetrafluoropropene (R1234) are highly toxic and should be removed. Because the boiling point of olefins such as R1233, R1224 and R1234 is similar to that of R245fa, it is difficult to completely separate these olefin impurities from R245fa by ordinary rectification, and other m...

AI Technical Summary

Problems solved by technology

[0003] The US "U.S. 6077982" specification published on June 20, 2000 disclosed that under the irradiation of 300-400nm ultraviolet light, the chlorine addition reaction of olefin impurities was produced by the photochlorination method to form saturated chlorine-containing chlorine with a higher boiling point. Hydrocarbons, and then removed by rectification, can reduce R1233zd with a content of 300-2000ppm in R245fa to less than 10ppm, and can effectively reduce the content of R1224, but at the same time as olefins are chlorinated, R245fa will also be chlorinated, reducing the Its purity, in addition, the efficiency of the photochlorination method is low, not suitable for industrial applications

This method is mainly used to remove high-content R1233zd (>10%) to about 1000-15000ppm, and due to the high proportion of extractant used, the ability to process crude R245fa in actual production is small, and it is not suitable for large-scale industrial production