1,1,1-Trihalogeno-4-methylpentenes, method of preparing the same and use of the same in the preparation of 1,1-dihalogeno-4-methyl-1,3-pentadienes

A process for producing a 1,1,1-trihalogeno-4-methylpentene of the formula ##STR63## wherein Z is a group of the formula ##STR64## or a group of the formula ##STR65## and X.sup.1, X.sup.2 and X.sup.3 are the same or different and each represents a halogen atom, which comprises removing R.sup.1 OH from a compound of the formula ##STR66## wherein R.sup.1 is a hydrogen atom or an alkyl, cycloalkyl, aryl, aralkyl or acyl group;

• and X.sup.1, X.sup.2 and X.sup.3 are as defined above in the presence of an effective amount of an acid catalyst or of an effective amount of at least one member selected from the group consisting of silica gel, aluminum silicate, kieselguhr, pumice, Fuller's earth, activated alumina and activated carbon.

A process for producing a 1,1,1-trihalogeno-4-methyl-3-pentene, which comprises removing R.sup.1 OH from a compound of the formula ##STR67## wherein R.sup.1 is a hydrogen atom or an alkyl, cycloalkyl, aryl, aralkyl or acyl group and X.sup.1, X.sup.2 and X.sup.3 are the same or different and each represents a halogen atom in the presence of an effective amount of an acid catalyst or of an effective amount of at least one member selected from the group consisting of silica gel, aluminum silicate, kieselguhr, pumice, Fuller's earth, activated alumina and activated carbon to obtain a mixture of a 1,1,1-trihalogeno-4-methyl-4-pentene of the formula ##STR68## wherein X.sup.1, X.sup.2 and X.sup.3 are as defined above and a 1,1,1-trihalogeno-4methyl-3-pentene of the formula ##STR69## wherein X.sup.1, X.sup.2 and X.sup.3 are as defined above and subjecting said mixture to fractional distillation to isolate said 1,1,1-trihalogeno-4-methyl-3-pentene with a first-emerging fraction rich in said 1,1,1-trihalogeno-4-methyl-4-pentene being recycled to the reaction system.

A process for producing a 1,1,1-trihalogeno-4-methylpentene of the formula ##STR70## wherein X.sup.1, X.sup.2 and X.sup.3 are the same or different and each represents a halogen atom and Z is a group of the formula ##STR71## or a group of the formula ##STR72## which comprises adding a haloform to a dimethyl vinyl carbinol compound of the formula ##STR73## wherein R.sup.1 is a hydrogen atom or an alkyl, cycloalkyl, aryl, aralkyl or acyl group under radical-reaction conditions to obtain a compound of the formula ##STR74## wherein R.sup.1, X.sup.1, X.sup.2 and X.sup.3 are as defined above and removing R.sup.1 OH from the last-mentioned compound III in the presence of an effective amount of an acid catalyst or of an effective amount of at least one member selected from the group consisting of silica gel, aluminum silicate, kieselguhr, pumice, Fuller's earth, activated alumina and activated carbon.

A process for producing a 1,1,1-trihalogeno-4-methyl-3-pentene of the formula ##STR75## wherein X.sup.1, X.sup.2 and X.sup.3 are the same or different and each represents a halogen atom, which comprises isomerizing a 1,1,1-trihalogeno-4-methyl-4-pentene of the formula ##STR76## wherein X.sup.1, X.sup.2 and X.sup.3 are as defined above by heating at a temperature of from 80.degree. to 200.degree. C. in the presence of 0.001 to 30%, based on the weight of said 1,1,1-trihalogeno-4-methyl-4-pentene, of at least one member selected from the group consisting of a transition metal of Group 6B, Group 7B or Group 8 of the Periodic Table of the Elements, a compound of said transition metal and an acid catalyst.

A process for producing a 1,1-dihalogeno-4-methyl-1,3-pentadiene of the formula ##STR77## wherein X and Y are the same or different and each represents a halogen atom, which comprises treating a 1,1,1-trihalogeno-4- methyl-3-pentene of the formula ##STR78## wherein X.sup.1, X.sup.2 and X.sup.3 are the same or different and each represents a halogen atom with a basic reagent at a temperature of from room temperature to 150.degree. C.

A process for producing a 1,1-dihalogeno-4- methyl-1,3-pentadiene of the formula ##STR79## wherein X and Y are the same or different and each represents a halogen atom, which comprises adding a haloform to a dimethyl vinyl carbinol compound of the formula ##STR80## wherein R.sup.1 is a hydrogen atom or an alkyl, cycloalkyl, aryl, aralkyl or acyl group under radical-reaction conditions to obtain a compound of the formula ##STR81## wherein R.sup.1 is as defined above and X.sup.1, X.sup.2 and X.sup.3 are the same or different and each represents a halogen atom;

• removing R.sup.1 OH from the compound III in the presence of an effective amount of an acid catalyst or an effective amount of at least one member selected from the group consisting of silica gel, aluminum silicate, kieselguhr, pumice, Fuller's earth, activated alumina and activated carbon to obtain a mixture of a 1,1,1-trihalogeno-4-methyl-4- pentene of the formula ##STR82## wherein X.sup.1, X.sup.2 and X.sup.3 are as defined above and a 1,1,1-trihalogeno- 4-methyl-3-pentene of the formula ##STR83## wherein X.sup.1, X.sup.2 and X.sup.3 are as defined above;
• subjecting said mixture to fractional distillation to isolate said 1,1,1-trihalogeno-4-methyl-3-pentene and treating said 1,1,1-trihalogeno- 4-methyl-3-pentene with a basic reagent at a temperature of from room temperature to 150.degree. C.