Patent GB-432188-A (GB)
Title: Improvements in or relating to the manufacture of agents for combating insects
Filed: 1933-04-24
Abstract: Carboxylic acid esters of cyanhydrins for use as insecticides have the general formula <FORM:0432188/IV/1> where R<1>, R<2> and R<3> denote the same or different saturated or unsaturated aliphatic, or cycloaliphatic, aromatic or heterocyclic radicles, such as methyl, ethyl, butyl, vinyl, propenyl, oleyl, phenyl, naphthyl, cyclohexyl, tetrahydronaphthyl, pyridyl, piperidyl, quinolyl, furfuryl, chloromethyl, chlorophenyl, nitrophenyl, aminophenyl and the like, or mixed radicles such as toluyl, xylyl, or cinnamenyl. R<1> or R<2>, or both, may also denote hydrogen.  Esters in which R<1> or R<2> is an unsaturated radicle and R<3> contains an aromatic nucleus may be prepared by acting with an aqueous solution of potassium or sodium cyanide on a mixture of an unsaturated aliphatic aldehyde and an aroyl halide or a substitution product thereof.  The reaction is preferably carried out at a low temperature in the presence of a solvent for the aldehyde employed.  Hitherto known methods may also be employed for the manufacture of any of the cyanhydrin esters. According to examples: acetic ester of cyclohexanone-cyanhydrin is prepared by the action of acetyl chloride on cyclohexanone cyanhydrin, and acetic or benzoic ester of crotonic aldehyde cyanhydrin by the action of acetyl chloride or benzoyl chloride on crotonic aldehyde cyanhydrin in the presence of pyridine.  The Specification as open to inspection under Sect. 91 refers to the preparation of various compounds as follows: (1) benzoic ester of crotonic aldehyde cyanhydrin is obtained by introducing a solution of sodium cyanide into a cooled mixture of crotonic aldehyde, benzene and benzoyl chloride, the reaction mixture is separated from the aqueous solution of common salt formed and is dried with calcium chloride and distilled in vacuo; (2) similarly 2,5-dichlorbenzoic ester of crotonic aldehyde cyanhydrin may be prepared by using the corresponding acid chloride; (3) benzoic ester of crotonic aldehyde cyanhydrin is prepared as in (1), but without cooling and without the addition of benzene; (4) benzoic ester of sorbic aldehyde cyanhydrin is similarly prepared from potassium cyanide, sorbic aldehyde and benzoyl chloride in presence of benzene; (5) benzoic ester of acrolein cyanhydrin is prepared as in (1), using acrolein as starting material; (6) benzoic ester of a -ethyl-b -propylacrolein is similarly prepared; (7) the naphthoic ester of crotonic aldehyde cyanhydrin is prepared as in (1), using naphthoic chloride.  This subject-matter does not appear in the Specification as accepted.ALSO:Insecticides consist of a carboxylic acid ester of a cyanhydrin together with a dispersing medium, which may be a solid such as talc, kieselguhr, coal dust or the like, or an insect powder of low efficiency, or, in the case of an ester of an unsaturated aliphatic cyanhydrin, may be a liquid, such as petroleum, or an ester, ether or ketone, or in the case of other cyanhydrin esters may be kerosene.  The active compounds have the general formula <FORM:0432188/VI/1> where R1 R2 and R3 denote the same or different saturated or unsaturated aliphatic or cycloaliphatic, aromatic or heterocyclic radicles, such as methyl, ethyl, butyl, vinyl, propenyl, oleyl, phenyl, naphthyl, cyclohexyl, tetrahydronaphthyl, pyridyl, piperidyl, quinolyl, furfuryl, chloromethyl, chlorophenyl, nitrophenyl, aminophenyl and the like, or mixed radicles such as toluyl, xylyl, or cinnamenyl.  R1 or R2 or both, may also denote hydrogen.  Examples refer to solutions in kerosene of the acetic esters of cyclohexanone cyanhydrin or crotonic aldehyde cyanhydrin, or of benzoic esters of crotonic aldehyde cyanhydrin or acetone cyanhydrin.  Acetone or carbon tetrachloride may be added to assist solution.  A further example refers to a mixture of the acetic ester of crotonic aldehyde cyanhydrin with talcum powder.  Esters in which R1 or R2 is an unsaturated radicle and R3 contains an aromatic nucleus may be prepared by acting with an aqueous solution of potassium or sodium cyanide on a mixture of an unsaturated aliphatic aldehyde and an aroyl halide or a substitution product thereof.  The reaction is preferably carried out at a low temperature in the presence of a solvent for the aldehyde employed.  Hitherto known methods may also be employed for the manufacture of any of the cyanhydrin esters. According to examples acetic ester of cyclohexanone-cyanhydrin is prepared by the action of acetyl chloride on cyclohexanone cyanhydrin, and acetic or benzoic ester of crotonic aldehyde cyanhydrin by the action of acetyl chloride or benzoyl chloride on crotonic aldehyde cyanhydrin in the presence of pyridin. The Specification as open to inspection under Sect. 91 is not limited as regards the liquid dispersion media to be amployed; contains additional examples as follows: (1) a mixture of the benzoic and acetic esters of crotonic aldehyde cyanhydrin is dissolved in kerosene, (2) the benzoic esters of furfurol cyanhydrin, acrolein cyanhydrin, sorbic aldehyde cyanhydrin or pinacoline cyanhydrin are mixed with talcum powder; and refers to the preparation of various compounds as follows: (1) benzoic ester of crotonic aldehyde cyanhydrin is obtained by introducing a solution of sodium cyanide into a cooled mixture of crotonic aldehyde, benzene and benzoyl chloride, the reaction mixture is separated from the aqueous solution of common salt formed and is dried with calcium chloride and distilled in vacuo; (2) similarly 2,5-dichlorbenzoic ester of crotonic aldehyde cyanhydrin may be prepared by using the corresponding acid chloride; (3) benzoic ester of crotonic aldehyde cyanhydrin is prepared as in (1) but without cooling and without the addition of benzene; (4) benzoic ester of sorbic aldehyde cyanhydrin is similarly prepared from potassium cyanide, sorbic aldehyde and benzoyl chloride in presence of benzene; (5) benzoic ester of acrolein cyanhydrin is prepared as in (1), using acrolein as starting material; (6) benzoic ester of a -ethyl-b -propylacrolein is similarly prepared; (7) the naphthoic ester of crotonic aldehyde cyanhydrin is prepared as in (1), using naphthoic chloride.  This subject-matter does not appear in the Specification as accepted.