GB816341A - Improvements in and relating to polymeric bis thiuram disulphides and fungicides derived therefrom - Google Patents

Abstract

Fungicidal products are prepared by reacting a polymeric bis thiuram disulphide of unit formula <FORM:0816341/IV (a)/1> where R is ethylene, propylene, phenylene or <FORM:0816341/IV (a)/2> with an alkali metal cyanide. The polymeric disulphides are prepared by oxidation of bis dithio carbamic acids or salts thereof in substantially neutral conditions by ammonium <PICT:0816341/IV (a)/1> persulphate, H2O2 or nitrous acid. The preferred cyanide is NaCN and is added in an aqeeous or alcoholic solution at a mildly alkaline pH. The preferred product is when R is ethylene and contains S, N, C and H, has a S content of 48-58 per cent, a m.p. of 155-185 DEG C., a light yellow colour, the infra-red absorption spectrum of the accompanying diagram and the X-ray diffraction pattern of Figs. 2 and 3 of the Specification (not shown). The products are soluble in hot chloroform and acetone, may be compounded with silicates (e.g. mica, talc, pyrophillate, clays), or may be dispersed with surface-active dispersing agents (e.g. alkyl phenoxy polyoxyethylene ethanol) and/or water or other liquid non-solvent for use as fungicide dusts and sprays. In examples: (1) disodium ethylene dithio carbamate is oxidized with the ammonium persulphate; the resultant polyethylene thiuram disulphide is reacted with NaCN; (2) as (1) but H2O2+conc. H2SO4 as the oxidizing agent; (3) as (1) but the oxidation and reaction with the cyanide are concurrent; (4) as (1) but an anhydrous reaction with the cyanide dissolved in methanol; (5) as (2) but derived from disodium-1,2-propylene bis dithiocarbamate; (6) as (2) but derived from tri-sodium diethylene tris dithio carbamate; (7) as (2) but derived from di-sodium p-phenylene bis dithio carbamate; in (8-11) is described the use of the ethylene substituted product as a fungicide, per se, in suspensions and in dispersions.ALSO:<PICT:0816341/VI/1> Fungicidal compositions are based on the reaction products of polymeric bis thiuram disulphides of unit formula <FORM:0816341/VI/1> where R is ethylene, propylene, phenylene or <FORM:0816341/VI/2> with alkali metal cyanides (for preparation see Group IV (a)). The preferred cyanide is NaCN. The preferred product is where R is ethylene and contains S, N, C and H, has an S content of 48-58 per cent, a m.p. 155-185 DEG C., a light yellow colour, the infra red absorption spectrum of the accompanying diagram and X-ray diffraction pattern of Figs. 2 and 3 of the Specification (not shown). The products are soluble in hot chloroform and acetone, may be compounded with silicates (e.g. mica, talc, pyrophillate, clays), or may be dispersed with surface-active dispersing agents (e.g. alkyl phenoxy polyoxyethylene ethanol) and/or water or other liquid non-solvent for use as fungicide dusts and sprays. Such dusts and sprays are described in Examples (8-11).