| 摘要 |
1354620 Pesticidal and pharmaceutical application of metal-containing polymers AUSTIN SCIENCE ASSOCIATES Inc 19 April 1971 [11 March 1970 21 Oct 1970] 23036/71 Headings A5B and A5E [Also in Divisions C1 and C3] Medicines, pesticides and herbicides comprise water-degradable, metal-containing polymers in which metal atoms are coordinated with bidentate carboxylic acid ligands, the atoms of the metal being in the polymer chain and linked to each other through the carboxyl groups. The polymers are obtained by reacting in a solvent a carboxylic acid with a soluble salt of the metal in the presence of an aldehyde. The metal may be calcium, magnesium, strontium, barium, radium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, cadmium, tantalum, tungsten, platinum, mercury, tin, lead, antimony, and the rare earth metals e.g. thorium. The polymers degrade on contact with water. Heating the polymer increases the molecular weight and produces a polymer which degrades less readily. Polymers may be prepared in which either the metal or the carboxylic acid is an active material which is gradually released as the polymer contacts moisture, or the polymer may be used to encapsulate material which is gradually released. Herbicides, insecticides, nematocides, fungicides, rodenticides and defoliants may be prepared in both these ways. When the active material forms a part of the polymer it may be dissolved in a solvent and sprayed or the solution coated on or absorbed in granular material. If the polymer is dissolved first in a nonionic surfactant it may be dissolved in water for a short time without degradation to enable it to be sprayed. Medicines e.g. insulin and thyroid extracts, may be encapsulated in the polymer for controlled release in the body, or a medicine, e.g. a salicylic acid compound, may be used to prepare the polymer. Calcium salts and maleic acid may be used to prepare polymers for use in medicines. For topical application of medicines and insect repellants, calcium salts and citric acid may be used. In Examples polymers are prepared by reactions in which the metal salts are ferric nitrate, cupric nitrate, cobaltous chloride, nickel nitrate, titanic trichloride, ferric chloride, calcium chloride, and the carboxylic acids are 2,4-dichlorophenoxy acetic acid, 2-methyl-3,6-dichlorobenzoic acid, benzoic acid, 2-(2,4,5-trichlorophenoxy) propionic acid, 4-amino-3,5,6-trichloropicolinic acid, 2,4, 5-trichlorophenoxy acetic acid and maleic acid; cinnamic aldehyde and benzaldehyde are used to catalyze the reactions. The herbicidal effects of polymers prepared from ferric nitrate and salts of 2,4-dichlorophenoxy acetic acid, 2,4,5- trichlorophenoxy acetic acid and 4-amino-3, 5,6-trichloropicolinic acid, is described, the polymer being distributed as sprays of polymer dissolved in acetone and as coatings of polymer on inert granular material and on fertilizer pellets. |
