US2357078A - Parasite control - Google Patents

Description

Patented Aug. 29, 1944 UNITED STATES j PATENT OFFICE PARASITE corrrnol.

Kenneth R. Brown, Kennett Square, Pm, minor to Atlas Powder Company, Wilmington, DeL, a corporation of Delaware No Drawing. Application August 25, 1941,

- Serial No. 408,218

13 Claims.

The present invention relates to parasite control.

An Object of the invention is to provide a parasiticide containing as an active ingredient a toxic partial lauric acid ester of one of a class of polyhydroxylic compounds. Another object is to control infestation of insects, by applying to the infested plants an aqueous spray containing such a partial ester as a esters as parasiticidal agents. In another application Serial Number 375,930, filed January 25, 1941, I have described and claimed synergistic combinations of said esters and various known parasiticidal agents,

The present invention relates to parasiticides containing as an active ingredient a water-dispersible composition of a partial lauric acid ester of a low molecular weight aliphatic polyhydroxylic compound of the type of polyhydr'ic alcohols, for example, ethylene glycol, glycerol, erythritol, pentaerythritol, hexitols, inositol; diand poly-condensation products of polyhydric alcohols, for

example, diethylene glycol, diglycero] and poly-,

glycerols;-and carbohydrates, for example, monoand oligo-saccharides. By low molecular weight as used to define the polyhydroxylic compounds descrlbed herein, I intend to exclude polyhydroxylic materials of molecular weights higher than those of the oligosaccharides.

By diand poly-condensation products I mean not only the straight external ethers, such as diglycerol, but also mixed external ethers, such as mannitol glycerol ethylene glycol ether, obtainable for example by successive condensation of mannitol with 1 mol of glycidol and 1 mol of ethylene oxide. I

The preferred compounds in the group described above are those in which the polyhydric residue is derived from a polyhydroxylic compound with not morethan 3 carbon atoms for each hydroxyl group, and in which the compounds (esters) have at east 1 hydroxyl group for each fatty acid rad- .lcal. These characteristics may b stated as:

males hydroxyl of the polyhydroxylic compound not over 3, and fatty acid hydroxyl of the ester not over 1. The compounds which meet these requirements are, in general, readily dispersible in their technical state of purity, and

have highinsecticidal value coupled with mini- 1 mum plant injury. In the preferred class the monoesters have been found most efficient. Examples of compounds meeting these requirements are:

(lei-hon atoms Hydroxyl Fatty acid I t r Compound polyhydroxylic Hydroxyl 0 es 9 7 compound 2 1 Ethylene glycol monolaurate. 1 =1 Glycerol monolaurate ';=1 ;=0.5 .Polyglycerol (containing 9 12 1 1 largely d tetra-glyc- -=1.s and .=2 =o.25 and =0 2 erol) monolaurate i 5 b 4 5 Diethylene glycol monolaui l i rate 2 l Pentaerythritol monolaurate. g=l 25 %=0.33 Mannitol dilaurate g=l i=0.5

The pure ester are generally difiicult to dis- .perse in water, and, probably for this reason, have inferior parasiticidal properties by comparison with mixed compositions. The mixtures may consist of different lauric acid esters such as the technical reaction products resulting from a'direct esterification of the polyhydroxylic compound and lauric acid. Very desirable complexity of product canbe obtained by employing in the esterification reaction a fatty acidimixture which has a major proportion of lauric acid and in addition substantial proportions of other fatty acids. A useful commercial source of such mixed acids is to be found in the mixed fatty acids derivable by hydrolysis of coconut oil. The preferred product for my purpose is, however, obtained by employing an alcoholysis reaction of the polyhydroxylic compound and a natural fat or oil, with a high content of combined lauric acid, to produce the partial lauric esters. Compositionsprepared by alcoholysis of coconutoil are the best from the standpoints of ease of dispersion in water andtoxicity.

Specific examples of partial esters and compositions useful in practising my invention are ethylene glycol monolaurate, alcoholysi product of coconut oil and ethylene glycol, glycerol monolaurate, polyglycerol-coconut oil alcoholysis product, diethylene glycol monolaurate, diethylene glycol-coconut oil alcoholysis product, pent- Y coconut oil with pentaerythritol.

These products can be prepared by procedures which are well known or obvious to the art. Alcoholysis reactions can be performed with heat stable polyhydroxylic compounds at elevated temperatures using a catalyst such as sodium hydroxide. The degree of esterification of the product is controllable by the ratio of fat or oil to polyhydroxylic compound. Monoesters are preferable for my purpose, hence a ratio of about 1 mol fat or oil to 2 mols polyhydroxylic material i recommended. Direct esterifications can be performed at high temperature if the reactants are heat stable. Cold reactions such as those involving acid chlorides and the polyhydroxylic compound can be used where necessary or desirable.

Whenever I refer to a water-dispersible composition" throughout this specification and claims it is intended that the partial lauric esters are water-dispersible either as such or by virtue of admixture with other esters,'and/or unreacted materials, produced in the course of making the product or added at a later time for the purpose of imparting water-dispersibility.

The invention is to be distinguished from the I use of small quantities of partial esters as spreading and wetting agents for other toxic materials. I have discovered that these partial lauric esters are themselves toxic to parasites, particularly as contact poisons to soft-bodied insects, when used in the form of aqueous dispersions. Dilutions of the ester materials for use as the toxic agents in prays will rarely run over 1 part ester to 1000 or 1200 parts water and more usual dilutions will be 1:400 or less. ,The dilution that can be used in a particular case depends on the ester used, the parasite to be controlled, manner of spraying, etc., as will be understood by the art.

Many parasites are killed by the lauric esters of the invention. Among the parasites controlled by the invention are soft-bodied sucking insects such as aphids, mites, cabbage loopers, the young and larvae of many hard-bodied insects, mosquito larvae, and many other parasites. Being contact poisons, the partial lauric esters of the invention must be applied to the insects themselves. Control is achieved by spraying an aqueous dispersion of the esters on the plants infested with the insects using care to wet the insects as thoroughly as possible. The lauric esters can be aD- plied to most-plants without injury at the dilution used. They are innocuous to warm blooded H mite (Tetranuchus te'larius) on greenhouse plants. 10

, The following examples give data on the behavior of some of the esters of the invention in controlling the red spider mite.

Example 1 Comparative tests were run on active stages of red spider mite (Tetranychus telarius) on bean leaves by precision spraying with the following compositions, the results being as indicated:

1 Alcoholysis product oi coconut oil.

Example 2 In addition t killing the active stages of red spider mite these compounds prevent the eggs from hatching. Eggs deposited by red spider mite on bean leaves were sprayed with the following compositions, hatchings were observed and the results were as set out:

Dilution Percent not Ester in water hatching Polyglycerol monolaurate 1:400 47. 6 D0 1 1:400 41. 4 Pentaerythritol monolaurate 1:400 67. 2 Do 1 1:400 67. 3

l Alcoholysis product of coconut oil.

Th usual spraying equipment and methods can be used for greenhouse and agricultural prac-' tice of the invention. The sprays can be made up as needed by dispersing the ester in water in accordance with usual practice.

The invention is not to' be taken as limited to the details and examples set out above except as defined in the following claims. Many examples of insecticidal efficiency could be presented but it is believed that the foregoing specification will be suillcient to indicate to those skilled in this art the type of uses that can be made of my invention, bearing in mind that many other types of insects can be controlled through the use of my parasiticides.

I claim:

1. A process for controlling insects which comprises applying to the insects an insecticide containing as an active ingredient a water-dispersible composition comprising a partial lauric acid ester of a low molecular weight aliphatic polyhydroxylic compound selected from the class consisting of polyhydric alcohols, diand poly-condensation products of polyhydric alcohols, and carbohydrates.

2. A process for controlling insects as in claim 1 wherein the said polyhydroxylic compound has a ratio of carbon atoms to hydroxyl groups not greater than 3 and wherein the said ester has a ratio of fatty acid residue to hydroxyl groups not greater than 1.

3. A process for controlling insects as in claim I wherein the said partial lauric acid ester is a monoester and wherein the. said polyhydroxylic compound has a ratio of carbon atoms to hydroxyl groups not greater than 3.

4. A process for controlling insects which comprises applying to the insects an aqueous insecticidal dispersion containing as an active ingredient a water dispersible composition comprising a partial lauric acid ester of a low molecular weight aliphatic polyhydroxylic compound selected from the class consisting of polyhydric alcohols and diand poly-condensation products of polyhydric alcohols, and the other products produced in the reaction of the mixed fatty acids derivable by hydrolysis of coconut oil and said polyhydroxylic compound.

5. A process for controlling insects which comprises applying to the insects an insecticide comprising the monolaurate Of a low molecular weight aliphatic polyhydroxylic compound selected from the class consisting of polyhydric alcohols and diand poly-condensation products oi polyhydric alcohols, and the other products of the reaction of about 1 mol of the mixed fatty acids derivable by hydrolysis of coconut oil and 1 mol of the said polyhydroxylic compound.

6. A process for controlling insects which comprises applying to the insects an insecticide containing as an active ingredient a water-dispersible composition comprising a partial lauric acid ester of a. low molecular weight aliphatic. polyhydroxylic compound selected from the class consisting of polyhydric alcohols and diand polycondensation products of polyhydric alcohols and the other products of the alcoholysis reaction of coconut oil with the said polyhydroxylic compound.

7. A process for controlling insects which comprises applying to the insects an aqueous insecticidal dispersion containing as an active ingredient a water-dispersible composition comprising the monolaurate of a low molecular weight aliphatic polyhydroxylic compound selected from the class consisting of polyhydric alcohols and diand poly-condensation products of polyhydric alcohols, and the other products of the alcoholysis reaction of about 1 mol of coconut oil and 2 mols of the said polyhydroxylic compound.

8. A process for controlling insects comprising applying to the insects an insecticide containing as an active ingredient a water-dispersible composition comprising a partial lauric acid ester of pentaerythritol.

9. A process for controlling insects comprising applying to the insects an insecticide containing as an active ingredient a water-dispersible composition comprising pentaerythritol monolaurate.

10. A process for controlling insects comprising applying to the insects an aqueous insecticidal dispersion containing as an active ingredient a water-dispersible composition comprising pentaerythritol monolaurate and the other products of the reaction of the mixed fatty acids derivable by hydrolysis of coconut oil and pentaerythritol in mol-for-mol proportions.

11. A process for controlling insects compr ing applying to the insects an aqueous insecticidal dispersion containing as an active ingredient a water-dispersible composition comprising pentaerythritol monolaurate and the other products of the alcoholysis reaction of about 1 mol of coconut oil with 2 mols of pentaerythritol.

12. A process for controlling insect infestations on plants which comprises applying to the intested plants an aqueous insecticidal spray containing as an active ingredient a water-dispersible. composition comprising a partial lauric acid ester of a low molecular weight aliphatic poly- I fested plants an aqueous insecticidal spray con-