DE1057815B - Carrier and conditioning agents for chemicals used in agriculture, e.g. B. Schaedlingsbekaempfungs- agent - Google Patents

Description

OEXJTIC

In the patent application P 10601 IV a / 12 i (German Auslegeschrift 1053 477) the production of tester powdery or finely divided organophilic or hydrophobic silicic acid-containing substances from a normally hydrophilic material is described, in which on the surface of a solid, finely divided hydrophilic silicic acid-containing material, the specific Has surface of at least 1 m * / g, chemically ester groups are bonded to make the surface at least organophilic or hydrophobic, ie to give it the property of being wetted by an organic solvent such as butanol in a butanol-water mixture .. preferably to become. This surface esterification is carried out by treating the silicic acid-containing material with primary or secondary alcohols with up to 18 carbon atoms in the core, preferably with constant removal of the water formed during the reaction and preferably at a temperature of at least 100 ° C. It is advisable to adjust the water content of the reaction mass under these circumstances to keep below 5% of the weight of the alcohol, preferably below 3, and to achieve maximum esterification below 1.5%. Substantially complete surface esterification results in a product which does not absorb methyl red from a benzene methyl red solution. In another method for esterifying a water-containing mixture of the hydrophilic silica-containing material in the presence of until heated to 30 weight percent water and in the presence of an alcohol under pressure and at _pH 4.5 to 7.5 at 270 to 375 ° C, then relieves the pressure maintaining the temperature above the critical value and then cooling the product in the substantial absence of air. Butanol is the preferred alcohol.

These surface-esterified silicic acid-containing substances are characterized by extremely high surface values and essentially consist of aggregates of dense amorphous spherical silicon dioxide particles, which are connected to form a porous network, the specific surface area of which is at least 1, preferably 25 m ² / g. For most purposes, these substances expediently have a specific surface area of 200 to 900, in particular 200 to 400 m ² / g.The diameter of the pores in these structures is more than 4 millimicrons, and the diameter of the spherical amorphous silicon dioxide particles forming the aggregates is preferably im Medium 5 to 150 millimicrons. Surface esterification means that the substrate should not be completely esterified.

These surface-esterified silicic acid Substances have remarkable properties that Carrier and conditioning agent for used in agriculture Chemicals e.g. B. Pesticides

Applicant:

E. I. du Pont de Nemours and Company, Wilmington, Del. (V. St. A.)

Representative: Dr.-Ing. W. Abitz. Patent attorney, Munich 27, Gaußstr. 6th

Ralph Kingsley Her, Guy B. Alexander, Edward Charles Broge,

Wilmington, Del., And Frederick John Wolter, West Chester, Pa.

(V. St. Α.),
have been named as inventors

give them excellent utility in a variety of uses.

The invention relates to a carrier and conditioning agent for used in agriculture Chemicals, including pesticides, which is characterized by the fact that it consists of a surface esterified silica-containing substance.

The pesticides are made by adding surface-esterified silicic acid Fabrics improved in many ways. An example of an excellent application of surface esterified products Silicic acid-containing substances is their use as diluents and extenders and Agents for preventing the caking of highly active insecticides such as 2,2-di- (p-methoxyphenyl) -1,1,1-trichloroethane and 2,2-di- (p-chlorophenyl) -l, l-trichloroethane. The silicic acid residues can Make up the main part of the insecticide and serve as a carrier for small amounts of the actual insecticide, but you can also use them in small quantities to prevent finely divided powdered insecticides, such as dichlorodiphenyltrichloroethane, to prevent. One can use the surface-esterified silicic acid-containing substances either alone or in conjunction with very cheap stretch

909 527/421

i UO / bib

use agents, ζ. B. low density clays, diatomaceous earth or wood flour.

Surface-esterified silicic acid-containing substances are also in the manufacture of pesticides as a dispersing agent in insecticide emulsions of the oil-in-water type are used. With their help one can finely divided hydrophobic insecticides transform into such a state that they distribute themselves in water. For example, dichlorodiphenyltrichloroethane can be used be pulverized with partially esterified siliceous substances, whereby Sufficient amounts of the silica-containing product are used to produce a very thin coating to form the surface of the dichlorodiphenyltrichloroethane particles. This dry powder can then be put in Water can be dispersed. The surface-esterified silicic acid-containing substances can not only be used as a coating can be applied to the surface of the particles of the insecticide, but they can also be the liquid insecticides themselves, ζ Β. melted Di-S Incorporate chlorodiphenyltrichloroethane, creating products which are more easily converted into flake form and dispersed in a finely divided state and have a lower tendency to stick together in the vessel.

Claims (1)

Claim .- · Use of a surface-esterified silica-containing substance as a carrier and conditioning agent for chemicals used in agriculture, e.g. B. Pesticides.