Method to purify and stabilize chloroolefins
The present invention is directed towards a method of purification of chloroolefins having 3 carbons and to a method to provide stable compositions of chloroolefins having 3 carbons. The chloroolefins are purified via the use of a solid absorbents for the removal of decomposition product such as phosgene and/or phosgene precursory from the reaction of the chloroolefins with oxygen. The chloroolefins stabilized against an increase of the phosgene level via the addition of inhibitors to the chloroolefins.
1. A method of removing and inhibiting the formation of decomposition products of oxygen and chloroolefins and/or chloroalkanes having 3 carbons from chloroolefins and/or chloroalkanes having 3 carbons selected from the group consisting of 1,1,2,3-tetrachloropropene (1230xa), 1,1,3,3 -tetrachloropropene (1230za), 1,1,1,2-tetrachloropropene (1230xf), 1,1,1,2,3-pentachloropropane (240db), 1,1,1,2,2-pentachloropropane (240ab) and mixtures thereof during storage in ferrous containers comprising contacting said chloroolefins and/or chloroalkanes with a water free, solid adsorbent selected from the group consisting of Al 2 O 3 , activated carbon and mixtures thereof having a surface area of from about 10 to 4000 m 2 /g and a porosity from about 0.005 to 0.5 cm 3 /g; and adding to said chloroolefins and/or chloroalkanes an inhibitor selected from the group consisting of α-methyl styrene, α-pineneoxide, β-pineneoxide, 1,2-hexadecene oxide, and mixtures thereof.
2. The method of claim 1 wherein said decomposition products comprise phosgene, phosgene precursors and acids.
3. The method of claim 2 wherein said acids comprise carboxylic acids and HCl.
4. The method of claim 1 wherein water is removed from said solid adsorbent prior to said contacting by heating and/or placing said solid adsorbent under a vacuum.
5. The method of claim 1 wherein said inhibitor is added in an amount from about 20 ppm to about 5 wt % of said chloroolefins and/or chloroalkanes.