US 5,849,963 A · Method for producing difluoromethane and 1,1,1,2-tetrafluoroethane · patentgrep

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Abstract

According to the method for producing difluoromethane and 1,1,1,2-tetrafluoroethane, having the steps of: (1) reacting methylene chloride and 1,1,2-trichloroethylene with hydrogen fluoride in a vapor phase In the presence of a fluorinating catalyst and 1,1,1,2-tetrafluoroethane in a first reactor; and (2) reacting 1,1,1-trifluorochloroethane with hydrogen fluoride in a vapor phase in the presence of a fluorinating catalyst in a second reactor, and supplying the reaction mixture from the second reactor to the first reactor, HFC-32 can be obtained in high conversion and high selectivity by fluorinating HCC-30 using commonly a large (excess) amount of HF which is required for producing HFC-134a.

Claims14

Dependent claims

A method for producing difluoromethane and 1,1,1,2-tetrafluoroethane, comprising the steps of:

(1) reacting methylene chloride with hydrogen fluoride in a vapor phase at a reaction temperature of 180.degree. to 320.degree. C. in the presence of a fluorinating catalyst and 1,1,1,2-tetrafluoroethane to give difluoromethane, and reacting 1,1,2-trichloroethylene with hydrogen fluoride to give 1,1,1-trifluorochloroethane, in a first reactor;
(2) reacting 1,1,1-trifluorochloroethane with hydrogen fluoride in a vapor phase at a reaction temperature of 280.degree. to 400.degree. C., which is higher than the reaction temperature of the first reactor, in the presence of a fluorinating catalyst to give 1,1,1,2-tetrafluoroethane in a second reactor, and supplying the reaction mixture from the second reactor to the first reactor;
(3) recovering difluoromethane, 1,1,1,2-tetrafluoroethane and hydrogen chloride from the reaction mixture of the first reactor;
and
(4) supplying the remainder of the reaction mixture containing 1,1,1-trifluorochloroethane from the first reactor to the second reactor after recovering in the step (3),
wherein said fluorinating catalyst is selected from:
(i) fluorinated chromium oxide obtained by fluorinating a heat-treated hydrate of chromium (III) with hydrogen fluoride,
(ii) chromium (III) trifluoride,
(iii) fluorinated aluminum oxide obtained by fluorinating aluminum oxide with hydrogen fluoride, and
(iv) a catalyst obtained by supporting one element selected from Ti, V, Zr, Mo, Ge, Sn and Pb on alumina, fluorinated alumina or partially fluorinated alumina.

7 more elements

A method for producing difluoromethane and 1,1,1,2-tetrafluoroethane, comprising the steps of:

(1) reacting methylene chloride with hydrogen fluoride in a vapor phase at a reaction temperature of 180.degree. to 320.degree. C. in the presence of a fluorinating catalyst and 1,1,1,2-tetrafluoroethane to give difluoromethane, and reacting 1,1,2-trichloroethylene with hydrogen fluoride to give 1,1,1-trifluorochloroethane, in a first reactor;
(2) reacting 1,1,1-trifluorochloroethane with hydrogen fluoride in a vapor phase at a reaction temperature of 280.degree. to 400.degree. C. in the presence of a fluorinating catalyst to give 1,1,1,2-tetrafluoroethane in a second reactor, and supplying the reaction mixture from the second reactor to the first reactor;
(3) reacting the reaction mixture from the first reactor with hydrogen fluoride in a vapor phase at a reaction temperature of 150.degree. to 240.degree. C., which is lower than the reaction temperature of the first reactor, in the presence of a fluorinating catalyst to reduce an amount of methylene chloride existing in the reaction mixture, in a third reactor;
(4) recovering difluoromethane, 1,1,1,2-tetrafluoroethane and hydrogen chloride from the reaction mixture of the third reactor;
and
(5) supplying the remainder of the reaction mixture containing 1,1,1-trifluorochloroethane from the third reactor to the second reactor after recovering in the step (4),
wherein said fluorinating catalyst is selected from:
(i) fluorinated chromium oxide obtained by fluorinating a heat-treated hydrate of chromium (III) with hydrogen fluoride,
(ii) chromium (III) trifluoride,
(iii) fluorinated aluminum oxide obtained by fluorinating aluminum oxide with hydrogen fluoride, and
(iv) a catalyst obtained by supporting one element selected from Ti, V, Zr, Mo, Ge, Sn and Pb on alumina, fluorinated alumina or partially fluorinated alumina.

8 more elements

A method for producing difluoromethane and 1,1,1,2-tetrafluoroethane, comprising the steps of:

(1) reacting methylene chloride with hydrogen fluoride in a vapor phase at a reaction temperature of 180.degree. to 320.degree. C. in the presence of a fluorinating catalyst and 1,1,1,2-tetrafluoroethane to give difluoromethane, and reacting 1,1,2-trichloroethylene with hydrogen fluoride to give 1,1,1-trifluorochloroethane, in a first reactor;
(2) reacting 1,1,1-trifluorochloroethane with hydrogen fluoride in a vapor phase at a reaction temperature of 280.degree. to 400.degree. C., which is higher than the reaction temperature of the first reactor, in the presence of a fluorinating catalyst to give 1,1,1,2-tetrafluoroethane in a second reactor, and supplying the reaction mixture from the second reactor to the first reactor;
(3) reacting the reaction mixture from the first reactor with hydrogen fluoride in a vapor phase at a reaction temperature of 150.degree. to 240.degree. C., which is lower than the reaction temperature of the first reactor, in the presence of a fluorinating catalyst to reduce an amount of methylene chloride existing in the reaction mixture, in a third reactor;
(4) reacting the reaction mixture from the third reactor with hydrogen fluoride in a vapor phase at 100.degree. to 190.degree. C., which is lower than the reaction temperature of the third reactor, in the presence of a fluorinating catalyst, in at least one fourth reactor;
(5) recovering difluormethane, 1,1,1,2-tetrafluoroethane and hydrogen chloride from the reaction mixture of the fourth reactor;
and
(6) supplying the remainder of the reaction mixture containing 1,1,1-trifluorochloroethane from the fourth reactor to the second reactor after recovering in the step (5),
wherein said fluorinating catalyst is selected from:
(i) fluorinated chromium oxide obtained by fluorinating a heat-treated hydrate of chromium (III) with hydrogen fluoride,
(ii) chromium (III) trifluoride,
(iii) fluorinated aluminum oxide obtained by fluorinating aluminum oxide with hydrogen fluoride, and
(iv) a catalyst obtained by supporting one element selected from Ti, V, Zr, Mo, Ge, Sn and Pb on alumina, fluorinated alumina or partially fluorinated alumina.

9 more elements

A method for producing difluoromethane and 1,1,1,2-tetrafluoroethane, comprising the steps of:

(1) reacting methylene chloride with hydrogen fluoride in a vapor phase at a reaction temperature of 180.degree. to 320.degree. C. in the presence of a fluorinating catalyst and 1,1,1,2-tetrafluoroethane to give difluoromethane, and reacting 1,1,2-trichloroethylene with hydrogen fluoride to give 1,1,1-trifluorochloroethane, in a first reactor;
(2) reacting 1,1,1-trifluorochloroethane with hydrogen fluoride in a vapor phase at a reaction temperature of 280.degree. to 400.degree. C., which is higher than the reaction temperature of the first reactor, in the presence of a fluorinating catalyst to give 1,1,1,2-tetrafluoroethane in a second reactor, and supplying the reaction mixture from the second reactor to the first reactor;
(3) reacting the reaction mixture from the first reactor with hydrogen fluoride in a vapor phase at 150.degree. to 240.degree. C., which is lower than the reaction temperature of the first reactor, in the presence of a fluorinating catalyst to reduce an amount of methylene chloride existing in the reaction mixture, in a third reactor;
(4) recovering difluormethane, 1,1,1,2-tetrafluoroethane and hydrogen chloride from the reaction mixture of the first reactor;
and
(5) reacting the remainder of the reaction mixture containing 1,1,1-trifluorochloroethane from the third reactor with hydrogen fluoride in a vapor phase at a temperature of 170.degree. to 320.degree. C. in the presence of a fluorinating catalyst in a fifth reactor after recovering in the step (4), and supplying the reaction mixture from the fifth reactor to the second reactor,
wherein said fluorinating catalyst is selected from:
(i) fluorinated chromium oxide obtained by fluorinating a heat-treated hydrate of chromium (III) with hydrogen fluoride,
(ii) chromium (III) trifluoride,
(iii) fluorinated aluminum oxide obtained by fluorinating aluminum oxide with hydrogen fluoride, and
(iv) a catalyst obtained by supporting one element selected from Ti, V, Zr, Mo, Ge, Sn and Pb on alumina, fluorinated alumina or partially fluorinated alumina.

8 more elements

A method for producing difluoromethane and 1,1,1,2-tetrafluoroethane, comprising the steps of:

(1) reacting methylene chloride with hydrogen fluoride in a vapor phase at a reaction temperature of 180.degree. to 320.degree. C. in the presence of a fluorinating catalyst and 1,1,1,2-tetrafluoroethane to give difluoromethane, and reacting 1,1,2-trichloroethylene with hydrogen fluoride to give 1,1,1-trifluorochloroethane, in a first reactor;
(2) reacting 1,1,1-trifluorochloroethane with hydrogen fluoride in a vapor phase at a reaction temperature of 280.degree. to 400.degree. C., which is higher than the reaction temperature of the first reactor, in the presence of a fluorinating catalyst to give 1,1,1,2-tetrafluoroethane in a second reactor, and supplying the resulting reaction mixture from the second reactor to the first reactor;
(3) reacting the reaction mixture from the first reactor with hydrogen fluoride in a vapor phase at 150.degree. to 240.degree. C., which is lower than the reaction temperature of the first reactor, in the presence of a fluorinating catalyst to reduce an amount of methylene chloride existing in the reaction mixture, in a third reactor;
(4) reacting the reaction mixture from the third reactor with hydrogen fluoride in a vapor phase at 100.degree. to 190.degree. C., which is lower than the reaction temperature of the third reactor, in the presence of a fluorinating catalyst, in at least one fourth reactor;
(5) recovering difluoromethane, 1,1,1,2-tetrafluoroethane and hydrogen chloride from the reaction mixture of the fourth reactor;
and
(6) reacting the remainder of the reaction mixture containing 1,1,1-trifluorochloroethane from the fourth reactor with hydrogen fluoride in a vapor phase at a temperature of 170.degree. to 320.degree. C. in the presence of a fluorinating catalyst in a fifth reactor after recovering in the step (5), and supplying the reaction mixture from the fifth reactor to the second reactor;
wherein said fluorinating catalyst is selected from:
(i) fluorinated chromium oxide obtained by fluorinating a heat-treated hydrate of chromium (III) with hydrogen fluoride,
(ii) chromium (III) trifluoride,
(iii) fluorinated aluminum oxide obtained by fluorinating aluminum oxide with hydrogen fluoride, and
(iv) a catalyst obtained by supporting one element selected from Ti, V, Zr, Mo, Ge, Sn and Pb on alumina, fluorinated alumina or partially fluorinated alumina.

9 more elements

Dependencies are inferred from the claim text.