An object of the present invention is to extend the catalyst lifetime in a method for producing fluoromethane by pyrolyzing fluorine-containing methyl ether in the presence of a catalyst. The present invention provides a method for producing fluoromethane by pyrolyzing a fluorine-containing methyl ether represented by Formula (1) in a gas phase in the presence of a catalyst,

the pyrolysis being conducted at a moisture concentration of 100 ppm or less,

##STR00001##

wherein R.sup.1 and R.sup.2 are identical or different, and each represents a substituted or unsubstituted straight or branched monovalent aliphatic hydrocarbon group, substituted or unsubstituted monovalent aromatic hydrocarbon group, substituted or unsubstituted monovalent cyclic aliphatic hydrocarbon group, hydrogen atom, or halogen atom.

An object of the present invention is to extend the catalyst lifetime in a method for producing fluoromethane by pyrolyzing fluorine-containing methyl ether in the presence of a catalyst. The present invention provides a method for producing fluoromethane by pyrolyzing a fluorine-containing methyl ether represented by Formula (1) in a gas phase in the presence of a catalyst,

the pyrolysis being conducted at a moisture concentration of 100 ppm or less,

##STR00001##

wherein R.sup.1 and R.sup.2 are identical or different, and each represents a substituted or unsubstituted straight or branched monovalent aliphatic hydrocarbon group, substituted or unsubstituted monovalent aromatic hydrocarbon group, substituted or unsubstituted monovalent cyclic aliphatic hydrocarbon group, hydrogen atom, or halogen atom.

Disclosed is a process for the preparation of 2,3,3,3-tetrafluoropropene, comprising the following two reaction steps: a. a compound having the formula CF.sub.3-xCl.sub.xCF.sub.2-yCl.sub.yCH.sub.2Cl undergoes gas-phase fluorination with hydrogen fluoride through n serially-connected reaction vessels in the presence of a compound catalyst producing 2,3-dichloro-1,1,1,2-tetrafluoropropane, 1,2,3-trichloro-1,1,2-trifluoropropane, and 1,3-dichloro-1,1,2,2-tetrafluoropropane; in said formula, x=1, 2, 3, y=1, 2, and 3≦x+y≦5; b. the 2,3-dichloro-1,1,1,2-tetrafluoropropane, 1,2,3-trichloro-1,1,2-trifluoropropane, and 1,3-dichloro-1,1,2,2-tetrafluoropropane undergo gas-phase dehalogenation with hydrogen in the presence of a dehalogenation catalyst, producing 2,3,3,3-tetrafluoropropene and 3-chloro-2,3,3-trifluoropropene, then separation and refining are performed, producing 2,3,3,3-tetrafluoropropene. The present invention is primarily used to produce 2,3,3,3-tetrafluoropropene.

Disclosed is a process for the preparation of 2,3,3,3-tetrafluoropropene, comprising the following two reaction steps: a. a compound having the formula CF.sub.3-xCl.sub.xCF.sub.2-yCl.sub.yCH.sub.2Cl undergoes gas-phase fluorination with hydrogen fluoride through n serially-connected reaction vessels in the presence of a compound catalyst producing 2,3-dichloro-1,1,1,2-tetrafluoropropane, 1,2,3-trichloro-1,1,2-trifluoropropane, and 1,3-dichloro-1,1,2,2-tetrafluoropropane; in said formula, x=1, 2, 3, y=1, 2, and 3≦x+y≦5; b. the 2,3-dichloro-1,1,1,2-tetrafluoropropane, 1,2,3-trichloro-1,1,2-trifluoropropane, and 1,3-dichloro-1,1,2,2-tetrafluoropropane undergo gas-phase dehalogenation with hydrogen in the presence of a dehalogenation catalyst, producing 2,3,3,3-tetrafluoropropene and 3-chloro-2,3,3-trifluoropropene, then separation and refining are performed, producing 2,3,3,3-tetrafluoropropene. The present invention is primarily used to produce 2,3,3,3-tetrafluoropropene.

The present invention provides a process for preparation of 2,3,3,3-tetrafluoropropene and intermediates thereof. Owing to its low global warming potential and zero ozone depleting potential, it is been proposed as a replacement for existing chlorofluorocarbons and hydrofluorocarbons as refrigerant.

The present invention provides a process for preparation of 2,3,3,3-tetrafluoropropene and intermediates thereof. Owing to its low global warming potential and zero ozone depleting potential, it is been proposed as a replacement for existing chlorofluorocarbons and hydrofluorocarbons as refrigerant.

The present invention provides a process for preparation of 2,3,3,3-tetrafluoropropene and intermediates thereof. Owing to its low global warming potential and zero ozone depleting potential, it is been proposed as a replacement for existing chlorofluorocarbons and hydrofluorocarbons as refrigerant.

The present invention relates to a process for purifying 1,1,1,2,3-pentafluoropropane, comprising the steps of: i) providing a composition A1 comprising 1,1,1,2,3-pentafluoropropane and 1,1,1,3-tetrafluoropropane; ii) purifying, preferably distilling, said composition A1 under conditions that are sufficient to form at least two streams including a first stream comprising 1,1,1,2,3-pentafluoropropane and a second stream comprising 1,1,1,3-tetrafluoropropane. The present invention also relates to a process for producing 2,3,3,3-tetrafluoropropene and a composition comprising 2,3,3,3-tetrafluoropropene.

The present invention relates to a process for purifying 1,1,1,2,3-pentafluoropropane, comprising the steps of: i) providing a composition A1 comprising 1,1,1,2,3-pentafluoropropane and 1,1,1,3-tetrafluoropropane; ii) purifying, preferably distilling, said composition A1 under conditions that are sufficient to form at least two streams including a first stream comprising 1,1,1,2,3-pentafluoropropane and a second stream comprising 1,1,1,3-tetrafluoropropane. The present invention also relates to a process for producing 2,3,3,3-tetrafluoropropene and a composition comprising 2,3,3,3-tetrafluoropropene.

The present invention relates to a process for purifying 1,1,1,2,3-pentafluoropropane, comprising the steps of: i) providing a composition A1 comprising 1,1,1,2,3-pentafluoropropane and 1,1,1,3-tetrafluoropropane; ii) purifying, preferably distilling, said composition A1 under conditions that are sufficient to form at least two streams including a first stream comprising 1,1,1,2,3-pentafluoropropane and a second stream comprising 1,1,1,3-tetrafluoropropane. The present invention also relates to a process for producing 2,3,3,3-tetrafluoropropene and a composition comprising 2,3,3,3-tetrafluoropropene.