Imperial Chemical Industries Limited

John Crosby

Robert Allan Rennie

Robert Michael Paton

Bernard W Terry

John A Milner

John Tanner

David J Milner

David Holland

Dale A Laidler

Peter L Ashcroft

3-(2'-chloro-3',3',3'-trifluoropropenyl)-2,2-dimethylcyclopropane-1-carboxy lic acid esters are prepared by dehydrohalogenation of the corresponding 3-(2',2'-dichloro-3',3',3-trifluoropropyl) compounds by reaction with an alkali metal carbonate in a polar aprotic solvent. The products are intermediates in the preparation of pyrethroid insecticides or are themselves insecticides.

Process for the preparation of cyclopropane carboxylic acid esters

A novel crystalline modification of an enantiomeric pair of isomers of the insecticide cyhalothrin having improved handling characteristics.

Insecticidal product

Process for the preparation of organic isocyanates in which a furoxan is heated in the presence of a vicinal diketo compound containing two adjacent keto carbonyl groups. When the furoxan ring is fused to an organic ring system di-isocyanates are produced. An adduct of the furoxan and the diketo compound may be isolated from the reaction mixture and used as a stable isocyanate precursor, for example, a 'one-pot' polyurethane composition.

Adducts of furoxan and vicinal diketones

3-Halogenoethyl- or propyl-2,2-dimethylcyclopropane carboxylic acid esters, which are intermediates in the preparation of synthetic pyrethroids, are prepared by the reaction of certain halogenopentenes or hexenes with a diazoacetic ester in the presence of a catalyst which is metallic copper or a copper (II) salt, a rhodium (II) salt of a carboxylic acid or a transition metal complex of certain chiral Schiff bases. By the use of the latter class of catalysts the yield of preferred cis IR isomer may be increased relative to the other possible isomers.

2,2-Dichloro-5-methyl-1,1,1-trifluorohex-4-ene, an intermediate in the synthesis of pyrethroid insecticides, is obtained by continuous distillation, preferably under sub-atmospheric pressure, of a mixture of 5-methyl-2,2,4-trichloro-1,1,1-trifluorohexane, dimethylformamide and lithium bromide, precipitating the chlorofluorocarbons from the distillate with water and separating the desired product from starting material by a further distillation.

Process for the manufacture of halogenated hydrocarbons

A halogenated hydrocarbon having the general formula: ##STR1## wherein Y represents fluorine, chlorine, bromine or --(CF.sub.2).sub.m W, R represents hydrogen or lower alkyl, R.sup.1 represents lower alkyl, X represents chlorine, bromine or iodine, W represents hydrogen, fluorine or chlorine and m is 1 or 2, is prepared by heating a compound having the general formula: ##STR2## wherein R, R.sup.1, X, Y, W and m have the meanings given above and Z represents chlorine, bromine or iodine, in a polar aprotic solvent together with an alkanolamine, optionally in the presence of a copper salt.

Halogenated hydrocarbons and a method for their preparation

Halogenated hydrocarbons, useful as insecticide intermediates, and

Improved elastomers are made by cross-linking a polyurethane through double bonds derived from a diisocyanato bicyclo octene used together with a linear prepolymer to make the polyurethane.

Cross-linkable filled polyurethanes based on unsaturated cycloaliphatic

Production of isocyanates

Process for the modification, e.g. cross-linking, of polymers containing C.dbd.C or C.tbd.C unsaturation by reacting them with nitrile sulphides or precursors therefor. A preferred system entails mixing the polymer with a 5-R-substituted-1,3,4-oxathiazol-2-one and heating the mixture to a temperature at which the nitrile sulphide is generated.

Process for modification of polymeric materials with a nitrile sulphide

2,4-DIISOCYANATO BICYCLO (3,3,0)-OCT-6-ENE, A NEW COMPOUND AND ITS PREPARATION AND USE ARE DISCLOSED.

2,4-Diisocyanato bicyclo (3,3,0)-oct-6-ene

A furoxan, especially one in which the furoxan ring is fused to a strained aliphatic ring system, is heated in the presence of sulphur dioxide to give an isocyanate. The process enables furoxans, such as dicyclopentadiene furoxan, which ring-open at temperatures &lt;180.degree. C to be converted into isocyanates. In the absence of sulphur dioxide, may be difficult to control the reaction and, in some cases, no isocyanate is obtained. Diisocyanates prepared by the process may be converted into polyurethanes by reaction with suitable hydroxylic compounds.

3,4-Cycloalkano furoxans are produced and are found to be useful in cross-linking of polymers.

3,4-Cycloalkano furoxans

The in situ thermal decomposition of specified furoxans to yield dinitrile oxides is used to modify a polyfunctional species. Preferred uses involve cross-linking of polymers, especially rubbers, but the process may also be used to form polymers from monomeric materials or to bind additives to polymeric substrates. Compositions incorporating polymeric materials and suitable furoxans may be used as 'one-shot' casting systems or be produced in the form of thermally curable sheets, etc, having useful shelf-lives.

Growing community of inventors

Manchester, United Kingdom

John Crosby