# US 4,393,227 A · Process for dechlorinating organic compounds > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,393,227 A - Document ID: US4393227A - Status: Granted - Kind: A - Application number: 06/292,060 - Filed: 1981-08-12 - Granted: 1983-07-12 - Earliest claimed: 1981-08-12 - Assignees: E. I. Du Pont de Nemours and Company - Inventors: Edward N. Squire - Web page: https://patentgrep.com/patent/US4393227A ## CPC - C07D 317/42: Halogen atoms or nitro radicals - C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08) ## Abstract Olefinic compounds are made from their vicinally chlorinated organic precursors by dechlorination with metallic magnesium in the presence of a mercury-based promoter, which may be a water-soluble mercury salt or metallic mercury, and of a catalytic amount of iodine. This process is particularly suitable for dechlorinating 4,5-dichloro-dioxolanes to the corresponding dioxoles. 4,5-Difluoro-2,2 bis(trifluoromethyl)-1,3-dioxole, which can be made by this process in a reproducible manner from 4,5-dichloro-4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxolane, is a useful monomer for making amorphous homopolymers and copolymers with tetrafluoroethylene, which are well suited for wire coating, finishes, and transparent glazing for corrosive service. ## Claims ### Claim 1 A process for dechlorinating an organic compound selected from the group consisting of ##STR4## where each of Y and Z independently is hydrogen, chlorine or fluorine, provided at least one of Y and Z is fluorine; and each of R.sup.3 and R.sup.4 independently is hydrogen, fluorine or trifluoromethyl to the ethylenically unsaturated compound, said process comprising contacting the organic chlorine-containing compound with at least a stoichiometric amount of metallic magnesium, a mercury based promoter selected from water-soluble mercury salts and metallic mercury, and iodine in the presence of tetrahydrofuran at a temperature from about room temperature to at least the boiling point of tetrahydrofuran at the operating pressure; with a proviso that magnesium amalgam can be used in lieu of magnesium and the mercury-based promoter. ### Claim 2 (depends on 1) The process of claim 1 wherein each of Y and Z is fluorine, and each of R.sup.3 and R.sup.4 is trifluoromethyl. ### Claim 3 (depends on 1) The process of claim 1 wherein each of Y and Z is hydrogen, and each of R.sup.3 and R.sup.4 is trifluoromethyl or fluorine. ### Claim 4 (depends on 1) The process of claim 1 wherein each of Y, Z, R.sup.3 and R.sup.4 is fluorine. ### Claim 5 (depends on 1) The process of claim 1 wherein Y is hydrogen; Z is fluorine; and each of R.sup.3 and R.sup.4 fluorine or trifluoromethyl. ### Claim 6 (depends on 1) The process of claim 1 wherein Y is chlorine; Z is fluorine; and each of R.sup.3 and R.sup.4 is trifluoromethyl or fluorine. ### Claim 7 (depends on 1) The process of claim 1 wherein the starting dioxolane is added gradually over a suitable period to a hot reaction medium consisting of tetrahydrofuran, magnesium, mercuric chloride, and iodine, and liquid is distilled from the reaction medium at such a rate that its volume, in milliliters, is greater than the amount of the starting dioxolane, in grams, added during the same period. ### Claim 8 (depends on 7) The process of claim 7 wherein the ratio of the volume of liquid recovered by distillation, in mL/min, to the weight of dioxolane added, in g/min, is about 1.1-10. ### Claim 9 (depends on 8) The process of claim 8 wherein the ratio is about 1.5-8 mL/g. ### Claim 10 (depends on 9) The process of claim 9 wherein the ratio is about 1.5-5 mL/g. ### Claim 11 (depends on 1) The process of claim 1 wherein the amount of magnesium is 1.1-8 gram-atoms per two gram-atoms of vicinal chlorine to be removed. ### Claim 12 (depends on 10) The process of claim 10 wherein the amount of magnesium is 2-6 gram-atoms per two gram-atoms of vicinal chlorine. ### Claim 13 (depends on 1) The process of claim 1 wherein the water-soluble mercury salt is selected from mercuric nitrate, mercuric chloride, mercuric acetate, and mercurous nitrate. ### Claim 14 (depends on 13) The process of claim 13 wherein the weight ratio of magnesium to mercury salt is 1:0.01 to 1:0.15, and the weight ratio of magnesium to iodine is 1:0.75 to 1:0.002. ### Claim 15 (depends on 14) The process of claim 14 wherein the mercury salt is a mercuric salt, and the weight ratio of magnesium to mercuric salt is 1:0.01 to 1:0.07, and the weight ratio of magnesium to iodine is 1:0.35 to 1:0.01. ### Claim 16 (depends on 15) The process of claim 15 wherein the weight ratio of magnesium to mercuric salt is 1:0.02 to 1:0.04, and the weight ratio of magnesium to iodine is 1:0.07 to 1:0.05. ### Claim 17 (depends on 1) The process of claim 1 wherein the mercury-based promoter is metallic mercury, and the weight ratio of magnesium to mercury is about 100:1 to 0.2:1. ### Claim 18 (depends on 1) A process of claim 1 which is carried out at atmospheric pressure within the temperature range of room temperature to the boiling temperature of tetrahydrofuran.