Process for production of 3,4-dichlorobutene-1

1. A process for producing 3,4-dichlorobutene-1 comprising the step of contacting 1,4-dichlorobutene-2 with a ferric carboxylate catalyst of the formula

where R is an alkyl or alkenyl group of 4-18 carbon atoms, a cycloalkyl or cycloalkenyl group of 6-18 carbon atoms or an aryl group selected from phenyl, benzyl, xylyl, tolyl, and naphthyl groups, whereby a portion of the 1,4-dichlorobutene-2 is isomerized to form 3,4-dichlorobutene-1.

2. A process of claim 1 wherein R is an alkyl group of 4-18 carbon atoms.

3. A process of claim 2 wherein the alkyl group is a 2-ethylhexyl group.

4. A process of claim 1 wherein R is a naphthyl group.

5. A process for producing 3,4-dichlorobutene-1 comprising the step of contacting 1,4-dichlorobutene-2 with a ferric carboxylate catalyst of the formula

where R, R′ and R″ are independently alkyl or alkenyl groups of 4-18 carbon atoms, cycloalkyl or cycloalkenyl groups of 6-18 carbon atoms or aryl groups selected from phenyl, benzyl, xylyl, tolyl, and naphthyl groups, the sum of m, n and o is 3 and m, n and o are independently 0, 1 or 2, whereby a portion of the 1,4-dichlorobutene-2 is isomerized to form 3,4-dichlorobutene-1.

6. A process of claim 1 wherein the amount of catalyst present ranges from 0.01-1.0 weight percent, based on the weight of dichlorobutenes present.

7. A process for producing an equilibrium mixture of 3,4-dichlorobutene-1 and 1,4-dichlorobutene-2 comprising the step of contacting a dichlorobutene isomer selected from the group consisting of 1,4-dichlorobutene-2,3,4-dichlorobutene-1 and mixtures thereof with a ferric carboxylate catalyst of the formula

where R is an alkyl or alkenyl group of 4-18 carbon atoms, a cycloalkyl or cycloalkenyl group of 6-18 carbon atoms or an aryl group selected from phenyl, benzyl, xylyl, tolyl, and naphthyl groups.