CH437906A - Process for the manufacture of pesticides - Google Patents

Description

  

      Process for the production of pesticides The reduction of the toxicity against warm-blooded animals, as well as the improvement of the duration of action of biocidal organic phosphorus compounds, is a problem of great practical importance.

   It has now been found that by adding adsorbable charcoal, both of the objectives, namely the aforementioned reduction in toxicity and the improvement in the duration of action, can be achieved to a surprisingly large extent.



  The present invention thus relates to a method for producing a pest control agent with a reduction in toxicity against warm-blooded animals and for extending the action of biocidal organic phosphorus compounds, the general formulas
EMI0001.0022
    wherein A and A 'are lower alkyl radicals, A "is hydrogen or methyl, X, X' and Z are oxygen or sulfur and Hal are halogen atoms, and of compounds,

   which can be derived from the above formulas by saturating the double bond with halogen atoms, as well as from biocidal organic phosphorus compounds of the general formulas.
EMI0001.0031
  
EMI0001.0032
         where R, R1, R3 and R4 are alkyl, cycloalkyl, aralkyl, aryl or heterocyclic radicals,

   where on the one hand R and R1 and on the other hand 14 and R4 can also be members of a ring system, R3 and R4 can also be hydrogen, where R2 is hydrogen, an alkyl radical or a halogen atom,

       R5 the rest
EMI0002.0016
       RE denotes where R6 is an alkyl,. Aryl or heteroylclic radical, X and Y for -0-, -S-, -NH- or and Z for oxygen or sulfur and
EMI0002.0026
   n and m are 1 or 2, characterized in that

      that these compounds are mixed in solid or liquid form with adsorbable charcoal.



  In particular, the present invention relates to a method for prolonging the action of dimethyl dichlorovinyl phosphate or the named derivatives thereof, in particular its homologues, characterized in that these esters are mixed with adsorbable charcoal, preferably activated charcoal;

      and, if appropriate, mixed with other carriers and / or with antioxidants.



  Examples of the volatile biocidal compounds mentioned include: dimethyl dichlorovinyl phosphate (DDVP), di-ethyl dichlorovinyl phosphate, di-isopropyl dichlorovinyl phosphate, di-n-propyl dichlorovinyl phosphate, di-n-butyl dichlorovinyl phosphate, di-iso-butyl dichlorovinyl phosphate, di- sec-butyl-dichlorovinyl phosphate,

      the connections of the formula
EMI0002.0065
         also dimethyl or diaethyl dibromo vinyl phosphate, methyl methyl dichlorovinyl phosphate.



  Among the compounds of the above general formula (IV) are those of the formula
EMI0002.0071
    To be emphasized because of their special suitability.



  Under the term adsorbable coal> are z. B. to understand substances with a high carbon content, which bind foreign substances through adsorption and / or capillary condensation and can at least partially release them again.



  These include B. charcoal, bone charcoal, blood charcoal; Adsorbable types of peat coal or of coke, in particular of lignite coke, also types of adsorbable coals, -as they are obtained from waste from paper or pulp production, e.g. B. from lignin obtained.



  Activated carbons may also be mentioned in particular; how they z. B. obtained by chemical treatment of sawdust, peat, fruit peels, z. B. act by loading with phosphoric acids, K2S, KSCN, KHS04, MgCl2, CaC12, ZnC12, H2S04, sulfur vapor.



  So-called medicinal charcoals, e.g. B. wood-based, can also be used, furthermore the so-called decolorization, water purification or gas mask carbons.



  The coal types in question can be used shaped or unshaped, the particle sizes or grain sizes being able to vary within relatively wide limits. In detail z. B. those adsorbable coals or

   Activated carbons are considered, which in ULLMANN, Techn. Enzyklopädie, Vol. 9, 1957, pp. 800-812, and in KIRK-OTHMER, Encycl. Chem. Technol. Vol. 2, pgs. 881-915 (1948). In general, the coal types mentioned should show a neutral to weakly acidic reaction.



  The following shows, for example, the effect of adding activated carbon of a certain quality (Carboraffin C, brand name) to DDVP using the adsorption isotherm of DDVP on this activated carbon at room temperature compared to water: cf. Figure which shows the said adsorption isotherm at room temperature (20 C) (ordinate: mg DDVP adsorbed / g carbon; abscissa: equilibrium concentration y DDVP / 1 solution]).



  An aqueous solution of 0.016 mg DDVP / liter H20 is in equilibrium with a charcoal weighing 1 g that is loaded with 2 percent by weight of DDVP;

          if the charcoal is loaded with DDVP at 5%, this corresponds to 0.15 mg DDVP / 1 water;

          with a 9% load 0.60 mg / l water and with an 11% load; 1.00 mg DDVP / 1 water.



  As explained above, the addition of 1 g of charcoal loaded with 5% by weight of DDVP (= 50 mg of DDVP) to 1 1 of water results in a concentration in the water of free DDVP of 0.15 mg / l. So per liter of aqueous medium only 0,

  15 mg = 0.3% of the total DDVP administered is released from the charcoal. If one applies these results, for example, to the presence of DDVP / activated charcoal mixtures in the digestive tract of warm-blooded animals, the chemical composition of the gastric respiratory tract, which deviates from a purely aqueous solution.

       Intestinal juices must be taken into account, so you can see that when DDVP / activated charcoal mixtures are absorbed through the gastrointestinal tract of warm-blooded animals, the risk of poisoning is reduced or largely excluded to an extent that has been achieved up to now. A similar result is obtained in the case of using the active substances listed at the beginning,

       especially in the case of the mentioned DDVP homologues. Is z. B. consumed free DDVP, such as by Hy drolysis, the level of free DDVP of 0.15 mg / 1 in the aqueous medium is replenished by replenishing the carbon / DDVP adsorbate. Similar relationships exist in the case of the active ingredients mentioned at the outset, in particular in the case of the DDVP homologues mentioned.

   This gives the preparations a lasting effect, the length of which, when used in a wäs serigem medium, practically only depends on the speed of the active ingredient disintegration in the water and on the charcoal. By loading the charcoal higher or by choosing a type of charcoal that is less adsorbent, the active ingredient concentration in the surrounding medium can be varied within wide limits, depending on the desired

      the concentration effective against the parasite and the amount of active substance tolerated by the treated warm-blooded animals. The adsorbable carbon or activated carbon mentioned at the beginning; can also be used to remove the active ingredients mentioned from aqueous solutions. The adsorption equilibrium can be achieved from either side; H. Charcoal loaded with active ingredient releases active ingredient into the water, depending on the prevailing conditions, or charcoal absorbs active ingredient from the aqueous active ingredient solution.



  A similar adsorption isotherm gives z. B. the system coal / DDVP / air: The adsorbed DDVP is in equilibrium with a certain DDVP concentration of a defined volume of air. If the DDVP concentration in the air is reduced by hydrolysis, air change, etc., the adsorbate will supply active substance until the equilibrium is established.

    This prevents an excessively high concentration of DDVP in the air, which could be toxic. When using the other active ingredients mentioned at the beginning, in particular the DDVP homologues, similar ratios occur.



  The method according to the invention can be carried out by simply mixing the components together.



  Depending on the intended use and type of active ingredient, it may be advantageous to prepare the mixture of charcoal / DDVP just before use, either by direct mixing of the components or by mixing charcoal with a powdery concentrate of the active ingredient, e.g. B. DDVP, on an absorbent inert carrier powder.



  The present invention also relates to an agent for combating pests obtained by the process according to the invention, optionally containing at least one of the following further additives: natural resins or chemical conversion products of the same, preferably rosin, finely divided SiO2 or

   Silicate; a carbohydrate or a mixture containing carbohydrate and / or proteins, antioxidants, dispersants, emulsifiers, wetting agents, thickeners, fillers or adhesives, which the pests can consume through feeding.



  Antioxidants which may be present as a further component in the pest control agents mentioned include the customary aliphatic and aromatic oxidation inhibitors, such as B.

         1,2-propylene glycol; 2,6-di-tert-butylphenol, butylhydroxyanisole; Bis- (3,5-di-tert-butyl-4-hydroxyphenyl) -methane, 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, 3,5-di-isopropyl-4-hydroxybenzyl alcohol, but also simpler phenolic compounds, such as, for example: hydroquinone, resorcin, pyrogallol.



  The agents mentioned can be used for general pest control, in crop protection and in hygiene, e.g. B. against harmful insects, acarids, nematodes, snails.



  They act against insects and acarids at their various stages of development; such as eggs, larvae, imagines, with an effect as contact and food poison being considered.



  A wide variety of bodies can be protected from the pests in question, with both liquid and solid bodies being able to be used as carriers of the active substance. As so ge to be protected or to be used as a carrier body come into question: Liquids, such as. B. water in ponds, and finally any dead and living solid surface, such.

   B. any objects in inhabited rooms, in basements, in screeds, in stables and living beings of the plant and animal kingdom in their various stages of development, provided they are insensitive to the pesticides.



  As emulsifiers or dispersants, which may be present as further components in the agents mentioned, nonionic products come into consideration, eg. B.

   Condensation products of aliphatic alcohols, amines or carboxylic acids with a long-chain hydrocarbon radical of about 10 to 30 carbon atoms with ethylene oxide,

      like the condensation product of octadecyl alcohol and 25 to 30 moles of ethylene oxide or that of technical oleylamine and 15 moles of ethylene oxide or that of -Dodecylmerkap- tau and 12 moles of ethylene oxide. Among the anionic emulsifying agents that can be used, the following should be mentioned:

      the sodium salt of dodecyl alcohol sulfuric acid ester, the sodium salt of dodecylbenzenesulfonic acid, the potassium or triethanolamine salt of oleic acid or abietic acid or mixtures of these acids,

   or the sodium salt of a petroleum sulfonic acid. Quaternary ammonium compounds, such as cetylpyridinium bromide, or dioxyethylbenzyldodecylammonium bromide, are used as cationic dispersants; or Dioxyäthylbenzyldodecylammoniumchlor- id into consideration.



  For the production of the new agents in the Firm of Litter and Dusting Agents, solid carriers, talc, kaolin, bentonite, cork flour and wood flour and other materials of vegetable origin can be used as additional additives. It is also very useful to manufacture the preparations in granulated form.

   The various forms of application of the new means for general pest control can be done in the usual way by adding substances that help distribute; improve the adhesive strength, the rain resistance or the penetration capacity; as such substances are mentioned: fatty acids. Resins, glue, casein or e.g.

   B. also alginates, As examples of the application of the new agents in crop protection is the treatment of Pflanzensa men and of fully or partially developed plants, as well as the soil in which the plants grow against harmful organisms such. B. against harmful nematodes, acarids and insects mentioned, the lack of phytotoxic side effects in the effective men concentrations of the new agents should be emphasized.

        The quantitative composition of the new preparations can fluctuate within relatively wide limits, depending on the saturation concentration of the active ingredient in question on the adsorbent, the adsorbed amount of the active ingredient z.

       B, 1 to 30 ohms, preferably 1-20% of the total weight of the adsorbate.



       In the following examples, percentages mean percentages by weight. <I> Example 1 </I> a) 2 g of DDVP are mixed with 98 g of activated charcoal (if necessary after drying in vacuo at 100 to constant weight).



  b) 30 g of di-iso-butyl dichlorovinyl phosphate (or another of the organic phosphorus compounds mentioned above) are mixed with 70 g of activated carbon.



  The agents obtained in this way are suitable for use in pest control and in hygiene. <I> Example 2 </I> In each 4 liters of distilled water, which was in a 20 cm deep container and in which there is approx.

   50 larvae of Aedes aegypti were in each case 24 mg of a finely ground 1% adsorbate of the following active ingredients
EMI0004.0048


 

Claims (1)

PATENT CLAIM I Process for the production of a pesticide with a reduction in toxicity against EMI0004.0054 interspersed with activated carbon. Part of the powdered bait sank to the bottom of the water; the other part, however, remained on the surface. The observation showed that the larvae in the shallow water can eat from the bait lying on the water bottom as well as from the bait floating above. The experiment was carried out in such a way that the effect was determined over a correspondingly long period of time after 24 or 48 hours and, in the positive case, the water was filled with fresh larvae. As a control, the above test was carried out under the same conditions, using the same amount of active ingredient, but without an activated charcoal carrier. The result is shown in the following table: EMI0004.0067 Carbon adsorbate <SEP> effectiveness <SEP> control <tb> of the <SEP> active ingredient <SEP> against <SEP> (active ingredient <SEP> without <tb> Aedes larvae <SEP> charcoal carrier <tb> in <SEP> days <SEP> effectiveness <SEP> against <tb> Aedes larvae <tb> in <SEP> days <tb> A <SEP> 33 <SEP> 4-6 <tb> B <SEP> 61 <SEP> 6 <tb> C <SEP> 29 <SEP> 1 - <B> -> </B> means that the effectiveness still persisted at the end of the test. Warm-blooded animals and prolonged action of biocidal organic phosphorus compounds of the general formulas EMI0004.0070 where A and A 'are lower alkyl radicals, A "is hydrogen or methyl, X, C, and Z are oxygen or sulfur and Hal are halogen atoms, as well as of compounds which differ from the above formulas by saturating the double bond with Let halogen atoms be derived, as from biocidal organic phosphorus compounds of the general formulas EMI0004.0079 where R, R1, R3 and R4 are alkyl, cycloalkyl, aralkyl, aryl or heterocyclic radicals, on the one hand R and R1 and on the other hand R3 and R4 can also be members of a ring system, Rs and R4 can also be hydrogen, in which R2 represents hydrogen, an alkyl radical or a halogen atom, R5 the rest EMI0005.0016 Rs is and RS is an alkyl, aryl or heterocyclic radical, X and Y are -0-, -S-, NH- or -NR and Z are oxygen or sulfur and n and m are 1 or 2, characterized in that one of these compounds in solid or liquid form is mixed with adsorbable charcoal. SUBCLAIMS 1. Process according to patent claim I, characterized in that dimethyl-2,2-dichlorovinyl phosphate is used as the phosphorus compound. 2. The method according to claim I and sub-claim 1, characterized in that activated carbon is used as the adsorbable carbon. PATENT CLAIM H Pesticide obtained by the method according to patent claim I.