Process to 1,1-dihalo-4-methyl-1,3-pentadienes, pyrethroid insecticide intermediates
AssigneeFMC Corporation
InventorAndrew Lupichuk
Life of this patent
Estimating the term…
Abstract
1,1-Dihalo-4-methyl-1,3-pentadienes, key intermediates in the synthesis of insecticidal dihalovinylcyclopropanecarboxylates, result from the condensation of 3-methyl-1-butene with a carbon tetrahalide in the presence of a catalyst, followed by the base-induced dehydrohalogenation of the 1,1,1,3-tetrahalo-4-methylpentane resulting from the condensation.
Claims12
A process for producing 1,1-dichloro-4-methyl-1,3-penadiene which comprises
- a. condensing a carbon tetrahalide, selected from the group consisting of carbon tetrachloride, bromotrichloromethane, and dibromodichloromethane, with 3-methyl-1l -butene in the presence of a free radical catalyst to produce a 1,1,1,3-tetrahalo-4-methylpentane;
- and then
- b. treating the 1,1,1,3-tetrahalo-4-methylpentane with an alkali metal hydroxide at a temperature between about 100.degree. C and 150.degree. C in a solvent selected from the group consisting of hydrocarbons and ethers, causing dehydrohalogenation, eliminating two moles of hydrohalic acid, producing said 1,1-dichloro-4-methyl-1,3-pentadiene.
A process for producing 1,1-dichloro-4-methyl-1,3-pentadiene which comprises
- a. condensing a carbon tetrahalide, selected from the group consisting of carbon tetrachloride, bromotrichloromethane, and dibromodichloromethane, with 3-methyl-1l -butene in the presence of a free radical catalyst to produce a 1,1,1,3-tetrahalo-4-methylpentane;
- and then
- b. treating the 1,1,1,3-tetrahalo-4-methylpentane with an alkali metal hydroxide at a temperature of about 0.degree. C in a solvent selected from the group consisting of alcohols and water, causing dehydrohalogenation, eliminating one mole of hydrohalic acid, producing a mixture of a 1,1,1-trihalo-4-methyl-2-pentene and a 1,1,1-trihalo-4-methyl-3-pentene;
- and then
- c. heating the mixture of pentenes at a temperature between about 125.degree. C and 175.degree. C, causing isomerization, yielding a 1,1,3-trihalo-4-methyl-1-pentene;
- and then
- d. treating the 1,1,3-trihalo-4-methyl-1-pentene with an alkali metal hydroxide at a temperature between about 100.degree. C and 150.degree. C in a solvent selected from the group consisting of hydrocarbons and ethers, causing dehydrohalogenation, eliminating a second mole of hydrohalic acid, producing 1,1-dichloro-4-methyl-1,3-pentadiene.
A process for producing 1,1-dichloro-4-methyl-1,3-pentadiene which comprises treating a 1,1,1,3-tetrahalo-4-methylpentane, selected from the group consisting of 1,1,1,3-tetrachloro-4-methylpentane, 3-bromo-1,1,1-trichloro-4-methylpentane and 1,3-dibromo-1,1-dichloro-4-methylpentane, with an alkali metal hydroxide at a temperature between about 100.degree. C and 150.degree. C in a solvent selected from the group consisting of hydrocarbons and ethers, causing dehydrohalogenation, eliminating two moles of hydrohalic acid, producing said 1,1-dichloro-4-methyl-1,3-pentadiene.
A process for producing 1,1-dichloro-4-methyl-1,3-pentadiene which comprises
- a. treating a 1,1,1,3-tetrahalo-4-methylpentane, selected from the group consisting of 1,1,1,3-tetrachloro-4-methylpentane,3-bromo-1,1,1-trichloro-4-methylpentan e and 1,3-dibromo-1,1-dichloro-4-methylpentane, with an alkali metal hydroxide at a temperature of about 0.degree. C in a solvent selected from the group consisting of alcohols and and water, causing dehydrohalogenation, eliminating one mole of hydrohalic acid, producing a mixture of a 1,1,1-trihalo-4-methyl-2-pentene and a 1,1,1-trihalo-4-methyl-3-pentene;
- and then
- b. heating the mixture of pentenes at a temperature between about 125.degree. C nd 175.degree. C, causing isomerization, yielding a 1,1,3-trihalo-4-methyl-1l -pentene;
- and then
- c. treating the 1,1,3-trihalo-4-methyl- 1-pentene with an alkali metal hydroxide at a temperature between about 100.degree. C and 150.degree. C in a solvent selected from the group consisting of hydrocarbons and ethers, causing dehydrohalogenation, eliminating a second mole of hydrohalic acid, producing 1,1-dichloro-4-methyl-1,3-pentadiene.
Dependencies are inferred from the claim text.