A method for producing tetrafluoromethane as follows is unlikely to damage a reaction apparatus and can produce tetrafluoromethane safely, inexpensively, and stably. To a raw material liquid containing a fluorinated hydrocarbon represented by chemical formula C.sub.pH.sub.qCl.sub.rF.sub.s (wherein p is an integer of 3 to 18, q is an integer of 0 to 3, r is an integer of 0 to 9, and s is an integer of 5 to 30) and having no carbon-carbon unsaturated bond, fluorine gas is introduced, and concurrently a reaction inducer is introduced in a gas state, giving tetrafluoromethane. The reaction inducer is reacted with fluorine gas to induce a reaction of forming tetrafluoromethane from the fluorinated hydrocarbon and the fluorine gas and is at least one reaction inducer selected from a hydrocarbon gaseous at normal temperature and pressure and hydrogen gas.

The process produces a fluorinated olefin from a fluorinated copolymer having at least one of sulfonic acid groups, carboxylic acid groups, or salts thereof. The process includes heating the fluorinated copolymer at a first temperature not more than 450 C. to decompose at least one of the sulfonic acid groups, carboxylic acid groups, or salts thereof to form a partially pyrolyzed intermediate and subsequently heating the partially pyrolyzed intermediate at a second temperature of at least 550 C. to produce the fluorinated olefin.

The process produces a fluorinated olefin from a fluorinated copolymer having at least one of sulfonic acid groups, carboxylic acid groups, or salts thereof. The process includes heating the fluorinated copolymer at a first temperature not more than 450 C. to decompose at least one of the sulfonic acid groups, carboxylic acid groups, or salts thereof to form a partially pyrolyzed intermediate and subsequently heating the partially pyrolyzed intermediate at a second temperature of at least 550 C. to produce the fluorinated olefin.

In a method for producing a low-molecular-weight fluorine compound by decomposing a fluororesin by bringing a heated microwave absorber into contact with a material containing a fluororesin in a reaction vessel provided with a carrier gas inlet and a decomposition gas outlet, (i) a temperature difference Delta 1(TRTI), obtained by subtracting the carrier gas temperature TI ( C.) from the temperature TR ( C.) of the heated microwave absorber, is set to be more than 500 C. and/or (ii) a temperature difference Delta 2(TRTE), obtained by subtracting the product gas temperature TE ( C.) at the outlet from the temperature TR ( C.), is set to be 300 C. or higher.

In a method for producing a low-molecular-weight fluorine compound by decomposing a fluororesin by bringing a heated microwave absorber into contact with a material containing a fluororesin in a reaction vessel provided with a carrier gas inlet and a decomposition gas outlet, (i) a temperature difference Delta 1(TRTI), obtained by subtracting the carrier gas temperature TI ( C.) from the temperature TR ( C.) of the heated microwave absorber, is set to be more than 500 C. and/or (ii) a temperature difference Delta 2(TRTE), obtained by subtracting the product gas temperature TE ( C.) at the outlet from the temperature TR ( C.), is set to be 300 C. or higher.

Provided is a method for producing a fluoromonomer with an excellent conversion rate of fluoropolymer. The method for producing a fluoromonomer include heating a fluoropolymer in the presence of a metal and/or alloy to obtain a fluoromonomer by thermal decomposition of the fluoropolymer, wherein: a heating temperature during the heating is 300 to 900 C.; and the metal and/or alloy is brought into a molten state during the heating.

Provided is a method for producing a fluoromonomer with an excellent conversion rate of fluoropolymer. The method for producing a fluoromonomer include heating a fluoropolymer in the presence of a metal and/or alloy to obtain a fluoromonomer by thermal decomposition of the fluoropolymer, wherein: a heating temperature during the heating is 300 to 900 C.; and the metal and/or alloy is brought into a molten state during the heating.

Provided is a method for producing a fluoromonomer with an excellent conversion rate of fluoropolymer. The method for producing a fluoromonomer according to the present invention includes heating a fluoropolymer in the presence of an organic sulfur compound to obtain a fluoromonomer by thermal decomposition of the fluoropolymer.

Provided is a method for producing a fluoromonomer with an excellent conversion rate of fluoropolymer. The method for producing a fluoromonomer according to the present invention includes heating a fluoropolymer in the presence of an organic sulfur compound to obtain a fluoromonomer by thermal decomposition of the fluoropolymer.