Disclosed is a process for the preparation of 1,3,3,3-tetrafluoropropene, comprising: (a) a compound having the formula CF.sub.3-xCl.sub.xCHClCHF.sub.2-yCl.sub.y and in the presence of a compound catalyst, undergoes, through n serially-connected reactors, gas-phase fluorination with hydrogen fluoride, producing 1,2,3-trichloro-1,1,3-trifluoropropane, and 1,2-dichloro-1,1,3,3-tetrafluoropropane; in said formula, x=1, 2 or 3; y=1 or 2, and 3≦x+y≦5; (b) 1,2,3-trichloro-1,1,3-trifluoropropane, and 1,2-dichloro-1,1,3,3-tetrafluoropropane undergo, in the presence of a dehalogenation catalyst, gas-phase dehalogenation with hydrogen, producing 3-chloro-1,3,3-trifluoropropene, and 1,1,3,3-tetrafluoropropene; (c) 3-chloro-1,3,3-trifluoropropene and 1,1,3,3-tetrafluoropropene undergo, in the presence of a fluorination catalyst, gas-phase fluorination with hydrogen fluoride, producing 1,3,3,3-tetrafluoropropene. The present invention is primarily used to produce 1,3,3,3-tetrafluoropropene.

A process for preparation of 3-Trifluoromethyl acetophenone oxime of formula I includes reacting an isomeric mixture of halo benzotrifluoride with Mg metal in an organic solvent in presence of a catalyst to obtain a Grignard complex. The Grignard complex is reacted with a ketene in hydrocarbon solvent in presence of transition metal ligand-acid complex to obtain an isomeric mixture of trifluoromethyl acetophenone. Finally, the isomeric mixture of trifluoromethyl acetophenone is reacted with hydroxylamine salt to obtain compound of formula I.

A process for preparation of 3-Trifluoromethyl acetophenone oxime of formula I includes reacting an isomeric mixture of halo benzotrifluoride with Mg metal in an organic solvent in presence of a catalyst to obtain a Grignard complex. The Grignard complex is reacted with a ketene in hydrocarbon solvent in presence of transition metal ligand-acid complex to obtain an isomeric mixture of trifluoromethyl acetophenone. Finally, the isomeric mixture of trifluoromethyl acetophenone is reacted with hydroxylamine salt to obtain compound of formula I.

The invention relates to a process for the preparation of compound of formula (I) wherein R.sub.1 is halogen and R.sub.2 is halogen or hydrogen; comprising a) reacting the compound of formula (II) in an aprotic organic solvent in the presence of an aprotic polar co-solvent with a magnesium amide base followed by a halogenating agent, to the compound of formula I wherein R.sub.1 is halogen and R.sub.2 is hydrogen, and b) reacting the compound of formula (I), wherein R.sub.1 is chloro and R.sub.2 is hydrogen, in an aprotic organic solvent in the presence of an aprotic polar co-solvent with a magnesium amide base followed by a halogenating agent to a compound of formula I, wherein R.sub.1 is chloro and R.sub.2 is halogen.

##STR00001##

The invention relates to a process for the preparation of compound of formula (I) wherein R.sub.1 is halogen and R.sub.2 is halogen or hydrogen; comprising a) reacting the compound of formula (II) in an aprotic organic solvent in the presence of an aprotic polar co-solvent with a magnesium amide base followed by a halogenating agent, to the compound of formula I wherein R.sub.1 is halogen and R.sub.2 is hydrogen, and b) reacting the compound of formula (I), wherein R.sub.1 is chloro and R.sub.2 is hydrogen, in an aprotic organic solvent in the presence of an aprotic polar co-solvent with a magnesium amide base followed by a halogenating agent to a compound of formula I, wherein R.sub.1 is chloro and R.sub.2 is halogen.

##STR00001##

The present invention provides a process for preparing 3,3,3-trifluoropropene (1243zf), the process comprising: (a) fluorinating CCl.sub.3CH.sub.2CH.sub.2Cl (250fb) to produce a reaction product comprising CF.sub.3CH.sub.2CH.sub.2Cl (253fb) in the liquid phase in a first reactor, using HF as the fluorinating agent; and (b) (i) dehydrohalogenating 253fb to produce 1243zf in the vapour phase in the present of a catalyst in a second reactor; or (b)(ii) dehydrohalogenating 253fb to produce 1243zf in a second reactor, wherein the reaction product comprising 253fb produced in step (a) has subjected to one or more purification steps before step (b).

The present invention also provides an azeotropic or near-azeotropic composition comprising HF and 253fb.

The present invention provides a process for preparing 3,3,3-trifluoropropene (1243zf), the process comprising: (a) fluorinating CCl.sub.3CH.sub.2CH.sub.2Cl (250fb) to produce a reaction product comprising CF.sub.3CH.sub.2CH.sub.2Cl (253fb) in the liquid phase in a first reactor, using HF as the fluorinating agent; and (b) (i) dehydrohalogenating 253fb to produce 1243zf in the vapour phase in the present of a catalyst in a second reactor; or (b)(ii) dehydrohalogenating 253fb to produce 1243zf in a second reactor, wherein the reaction product comprising 253fb produced in step (a) has subjected to one or more purification steps before step (b).

The present invention also provides an azeotropic or near-azeotropic composition comprising HF and 253fb.

The present invention provides a process for preparing 3,3,3-trifluoropropene (1243zf), the process comprising: (a) fluorinating CCl.sub.3CH.sub.2CH.sub.2Cl (250fb) to produce a reaction product comprising CF.sub.3CH.sub.2CH.sub.2Cl (253fb) in the liquid phase in a first reactor, using HF as the fluorinating agent; and (b) (i) dehydrohalogenating 253fb to produce 1243zf in the vapour phase in the present of a catalyst in a second reactor; or (b)(ii) dehydrohalogenating 253fb to produce 1243zf in a second reactor, wherein the reaction product comprising 253fb produced in step (a) has subjected to one or more purification steps before step (b).

The present invention also provides an azeotropic or near-azeotropic composition comprising HF and 253fb.

The present invention relates to a process for the preparation of a compound of formula I (I), comprising reacting a compound of formula II (II), with a brominating agent in the presence of an acidic catalyst to a compound of formula III (III), and reacting the compound of formula III in tetrahydrofuran or 2-methyl-tetrahydrofuran with potassium tert-butoxide to a compound of formula I.

##STR00001##

The present invention relates to a process for the preparation of a compound of formula I (I), comprising reacting a compound of formula II (II), with a brominating agent in the presence of an acidic catalyst to a compound of formula III (III), and reacting the compound of formula III in tetrahydrofuran or 2-methyl-tetrahydrofuran with potassium tert-butoxide to a compound of formula I.

##STR00001##