GB2123824A - 4-Methyl-2,3,5,6-tetrafluorobenzyl acetate and a process for its preparation - Google Patents

4-Methyl-2,3,5,6-tetrafluorobenzyl acetate and a process for its preparation Download PDF

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Publication number
GB2123824A
GB2123824A GB08318139A GB8318139A GB2123824A GB 2123824 A GB2123824 A GB 2123824A GB 08318139 A GB08318139 A GB 08318139A GB 8318139 A GB8318139 A GB 8318139A GB 2123824 A GB2123824 A GB 2123824A
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Prior art keywords
methyl
preparation
acetate
tetrafluorobenzyl
tetrafluoro
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GB08318139A
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GB8318139D0 (en
GB2123824B (en
Inventor
David John Milner
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Imperial Chemical Industries Ltd
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Imperial Chemical Industries Ltd
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Priority to GB08318139A priority Critical patent/GB2123824B/en
Publication of GB8318139D0 publication Critical patent/GB8318139D0/en
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Publication of GB2123824B publication Critical patent/GB2123824B/en
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
    • C07C69/62—Halogen-containing esters
    • C07C69/63—Halogen-containing esters of saturated acids
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C67/00—Preparation of carboxylic acid esters
    • C07C67/035—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with saturated hydrocarbons

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

4-Methyl-2,3,5,6-tetrafluorobenzylacetate, a chemical intermediate useful in the synthesis of pestidical compounds, is prepared by contacting tetrafluoro-p-xylene with oxygen in the presence of a mixture of cobalt and sodium acetates, sodium bromide and acetic acid and its anhydride.

Description

SPECIFICATION 4-Methyl-2,3,5,6-tetrafluorobenzyl acetate and a process for its preparation This invention relates to 4-methyl-2,3,5,6-tetrafluorobenzylacetate, a chemical intermediate useful in the synthesis of pesticidal compounds, and a process for its preparation.
According to one aspect of the invention, there is provided a novel compound of the formula (I):
which is 4-methyl-2,3,5,6-tetrafluorobenzylacetate.
The compound may be prepared by the selective oxidation of tetrafluoro-p-xylene under specific conditions.
Thus according to another aspect of the invention there is provided a process for the preparation of 4-methyl-2,3,5,6-tetrafluorobenzylacetate which comprises contacting tetrafluoro-p-xylene with oxygen in the presence of a mixture of cobalt and sodium acetates, sodium bromide, and acetic acid and its anhydride.
Conveniently, the tetrafluoro-p-xylene is stirred together with the mixture of ingredients under an atmosphere of oxygen at a temperature of about 1 1 OOC. The progress of reaction, which may take up to 20 hours, can be followed by examining samples withdrawn at intervals by gas layer chromatography. The process is more particularly described in the Example which follows later.
A similar process for preparing p-methylbenzylacetate from p-xylene is described in the Canadian Journal of Chemistry, 43(1965), page 1306 by Hay and Blanchard. In this process a substantial amount of p-tolualdehyde is formed, viz. 39% yield as against 57% yield of p-methylbenzylacetate.
Surprisingly, very little tetrafluoro-p-tolualdehyde is formed in the process of the present invention.
The tetrafluoro-p-xylene starting material may be obtained by the dimethylation of 1,2,4,5tetrafluorobenzene with a methyl halide, conveniently methyl chloride, in the presence of a Lewis acid, such as aluminium chloride, using Friedel-Crafts reaction. The reaction is carried out under pressure in an autoclave at a temperature of about 1 500 C.
The preparation of 1 ,2,4,5-tetrafluorobenzene is described in, for example, the Journal of the American Chemical Society, Vol. LXXIII, January-March, 1951; pp. 145 to 149.
The benzylacetate is a precursor of 4-methyl-2,3,5,6-tetrafluorobenzyl alcohol which is useful for the preparation of pesticidal esters. The alcohol is obtained by the hydrolysis of the acetate.
The invention is illustrated by the following Example.
Example Preparation of 4-methyl-2,3,5,6-tetrafluorobenzylacetate A mixture of tetrafluoro-p-xylene (13.35 g; 0.075 mol), cobalt acetate (1.0 g; 0.004 mol), sodium acetate (0.272 g; 0.002 mol), acetic anhydride (9.29 g; 0.091 mol) and acetic acid (10 ml) was stirred under an atmosphere of oxygen. The temperature of the mixture was increased to 1100 and samples were withdrawn at intervals for examination by gas layer chromatography (glc). After 20 hours, about 40% of the tetrafluoroxylene had been consumed. Very little 4-methyl-tetrafluorobenzaldehyde was present and there was one major volatile product. Glc-mass spectrometry (5 ft 10% E301 column with a programmed run of 100 to 2500) showed this major product to have a molecular ion at m/e 236 and fragments at 1 93, 177, 1 63. This is in agreement with the structure:
The products were drowned in water, extracted with ether, the ether extracts washed and dried and solvent removed to leave 10.3 g of an oil.

Claims (3)

Claims
1. 4-Methyl-2,3,5,6-tetrafluorobenzylacetate.
2. A process for the preparation of 4-methyl-2,3,5,6-tetrafluorobenzylacetate which comprises contacting tetrafluoro-p-xylene with oxygen in the presence of a mixture of cobalt and sodium acetates, sodium bromide, and acetic acid and its anhydride.
3. A process for the preparation of 4-methyl-2,3,5,6-tetrafluorobenzyl acetate substantially as herein described with reference to the Example.
GB08318139A 1982-07-21 1983-07-05 4-methyl-2 3 5 6-tetrafluorobenzyl acetate and a process for its preparation Expired GB2123824B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08318139A GB2123824B (en) 1982-07-21 1983-07-05 4-methyl-2 3 5 6-tetrafluorobenzyl acetate and a process for its preparation

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8221037 1982-07-21
GB08318139A GB2123824B (en) 1982-07-21 1983-07-05 4-methyl-2 3 5 6-tetrafluorobenzyl acetate and a process for its preparation

Publications (3)

Publication Number Publication Date
GB8318139D0 GB8318139D0 (en) 1983-08-03
GB2123824A true GB2123824A (en) 1984-02-08
GB2123824B GB2123824B (en) 1986-07-30

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GB08318139A Expired GB2123824B (en) 1982-07-21 1983-07-05 4-methyl-2 3 5 6-tetrafluorobenzyl acetate and a process for its preparation

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4783547A (en) * 1986-04-18 1988-11-08 Ici Americas Inc. Polyfluoroaromatic nitriles
US4866185A (en) * 1986-04-18 1989-09-12 Ici Americas Inc. Difunctional polyfluoroaromatic derivatives and a process of preparing the same
US4965394A (en) * 1986-04-18 1990-10-23 Ici Americas Inc. Difunctional polyfluoroaromatic derivatives and a process of preparing the same
WO2002034707A1 (en) * 2000-10-27 2002-05-02 Syngenta Limited Preparation of 4-methyl-2,3,5,6-tetrafluorobenzyl alcohol

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4783547A (en) * 1986-04-18 1988-11-08 Ici Americas Inc. Polyfluoroaromatic nitriles
US4866185A (en) * 1986-04-18 1989-09-12 Ici Americas Inc. Difunctional polyfluoroaromatic derivatives and a process of preparing the same
US4965394A (en) * 1986-04-18 1990-10-23 Ici Americas Inc. Difunctional polyfluoroaromatic derivatives and a process of preparing the same
WO2002034707A1 (en) * 2000-10-27 2002-05-02 Syngenta Limited Preparation of 4-methyl-2,3,5,6-tetrafluorobenzyl alcohol
US6894195B2 (en) 2000-10-27 2005-05-17 Syngenta Limited Preparation of 4-methyl-2,3,5,6-tetrafluorobenzyl alcohol

Also Published As

Publication number Publication date
GB8318139D0 (en) 1983-08-03
GB2123824B (en) 1986-07-30

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 19920705