US2469869A - Production of water repellent heavy metal nicotine silicates - Google Patents

Description

= gicidal properties.

. .such as --copper, zinc, .rnercury, ,iorm coznplexsalts(see ,Clompt. ,litend. .Acad. Sci.-

Patented May 10, 1949 ,UNI-I STATES .rRonUcmIoN OF WATER BEPE LENJ." E VY METALNICOIINE Frederick E. Dearborn, Washingto flDJiG. No. ,Drawling. firiginal application :Nooenibei' Ill,

1945, Serial 'No.

627,270. Divided failiiifliisap plication May is, 941,scanner-2433545 2. Claims. (.GhLZGOr-IQVDJ (Granted This application is made under the-act of March 3, 1883, as amended by the act of April 30, 1928, andthefinventiori herein described, if

1 patented, mayhe manufactured and used "by or for the Gover'mne'n'tof the -United States of.

and it has v as;its:;pnime:object.the provision oi, which :contain fixed lnicosuch new compositions tine. as the principal toxic ingredient.

Another object of .-.the invention is to provide such compositions which are more toxic to insects than nicotine alone and which acan be applied to vegetation ,eitheras :a spray or as .a out causing injury to .plants.

dustwith- A- f-urther. objectis- .to-stabilize the nicotine against thgdestructitxeaction .of sunlight and the leaching deflectotxaimwhenthecompositions are applied to negetation, thus prolonging their usefulness.

Otherobiects will beapparent.irom'the description of the invention.

It is well known that nicotine, while being a.

highly efficient insecticide; both as a contact and as a stomach poison, does not possess any fun- F'urthermore, nicotine is not stable against'the' destructive action of sunlight, which, through'its ultra-violet and visible short wave-length rays, readilyoxidizesor otherwise reduces the toxicity of nicotine in a short time, thus rendering it "ineffective and necessitating frequent application in "order to insure control of insects. In this invention, however, the nicotine is stabilized against the destructive effects of sunlight by 'being chemically "combined with a suitable metallic salt, the-metallic salt blocking the :suns zraysz-andthus:preventing them from decomposing thenicotine. This Linventiomi-urthermore 'in :addition to providing-products which have the desirable properties described :above,provides a process whereloyathezsame products of the invention are renderedwater-repellent, thus negating the leachinggefieot of :rain or other sources of water.

Nicotine, and many of its salts such as nicotine sulfate, combines with-certain heavy metallic salts Patent2,466,157, April 5,

and others, to

-anazne .codling .(Paris) 14,: 22.4,, .22 r 1. .looth .asi.as. contact an appreciably iiicre'as. L .tion withsuch heavy under the act joffzMarch f :amended April 30, 1928,; 3'70 IQj.

-s?12- andlthei-r toxiclty :as' asto nach poison, are lien .cli'emical mnibinainetallic salts. 'ifilhis f has d againsfithe cockroach rvael Copper, iinsnuni lousinsoluhle.or-slightly sol- 'uble compoundalha'sil'on .peenmeco'gnizec as a.

been shown Ehy Lt'ests;

.Mercury co po nds'lare'.

used.

sively used as Recently, Iz'ihc compounds have been iis'edeffect ve131 :against certainiilingi.

e11 known ibactericides galso be'en extensively and fungicides, anatn In the present invention, insoluble heavy metal salts such .as copper. ,zinc and 'Inercury silicates,

are chemically iconib jedw'th nicotine-in anovel metal silicates. .Th I I v a vcates have combined insecticidal. and fungicidal properties in ese' iilootiiie heavy metal silih" the ,rtoxiclty of the nicotine jpreciably increased;

v tioned aboveifthe r a v he -mama is"'.sta'bilized against the ,destru'ctive rays'ior the sunifland the product itself may be suspended "in water or ground. to arii'rredust'fandtapplied either :as a

spray or as a dust'to vegetation tvithout causing any 'injuryto the plants. f Furthermore; as meni fi in the above properties, may be" 'rendered water repellent (by a mrocessfto hefilater des'cribedf' i'I'he ordinary mechanical I paration and: armor" 'iung'icide, *for example.

' mechanical Lmi ture was applied to apple-tree foliage f in tests; conducted against .the :codllng The compositions of jthe invention, which .are

I insoluble .nicdtin e-heavyimetalfisilicates,"such as 'xeither of twoime'th' iis method A andimethbdfiBi' nicotine-copper:silicate;"'gnicotine zin'c ,sili'cate, and nicotine-mercury silicate: can be prepared by hereinafter designated as e a Method .A involves nemic-any reacting a water suspension of .iaiif insoluble vheavy iiiejtalf silicate yfzra'c'ting a schiblgsubprepared Joy 'chen ica chemically reacting a nicotine-soluble heavy metal salt with a solution of substantially pure sodium silicate. In both of these methods, the reactions are conducted at a temperature of about from 50 to 100 C. These methods will be described later in greater detail.

The products resulting from either of these methods of preparation are, filtered, dried, and then ground to a very fine-dust, the smaller the particle size, the greater the toxicity to insects and the greater the foliage coverage.

The products are insoluble solids containing about 10 percent or more of chemically combined nicotine, are stable to sunlight, and readily ground to a fine dust. 'They possess high, combined insecticidal and fungicidal properties. They are readily suspended in. water without the use of a wetting agent and are :easily applied to vegetation, either as a spray or as a dust, with out causing plant injury.

If it is desired to obtain a water-repellent product which will not be wet'by'water without the addition of a wetting agent,'about 1 to 5 percent by weight of a soluble alkali salt of a solid monocarboxylic acid containing or more carbon atoms (one that is normally solid at ordinary room temperature) such as sodium stearate, so-

dium palmitate, and so forth, in solution, is added and mixed well with the water suspension of method A or to the sodium silicate solution in method B, before reacting with the nicotine or nicotine sulfate. This alkali salt of the monocarboxylic acid apparently enters into the reaction, since a uniform product results which is water repellent.

The water-repellent products possess the same characteristics as the water-wettable products, with the exception that they are not wet by water without the use of a wetting agent, and when properly applied to foliage, are less readily removed by water than is the water-wettable product. The water-repellent, products are more suitable for dusting than for spraying, since they do not produce as good a suspension in water as does the water-wettable product.

In preparing the new compositions of matter according to method A, a water suspension of a heavy metal silicate such as copper silicate, zinc silicate, mercuric silicate, and a solution of free nicotine (present as the free alkaloid) or nicotine sulfate are chemically reacted at a temperature of about from 50 to 100 C. The heavy metal silicate used can be a Washed and dried -material which has been finely ground, or a freshly precipitated material which has been freed from soluble salts by washing. If the reactants are used in the exact chemical proportions for combination, the reaction will proceed to neutrality. However, to use these exact proportions is inconvenient, and it is preferred to use an excess of the nicotine or nicotine sulfate.

If excess nicotine sulfate is used in the process, some of the metal of the metal silicate will be dissolved'because of the development of acidity, presumably due to the splitting-off of free sulfuric acid from the nicotine sulfate during the reaction. It is therefore important to maintain substantial neutrality of the reaction mixture,

and this is accomplished by the addition of a dilute solution of sodium silicate (water glass).

If excess free nicotine is used, the reaction mixture becomes alkaline and should be neutralized by the addition of a solution of a soluble salt of the heavy metal being used as one of the reactants. If not neutralized, an alkaline condi- Example I To prepare 100 grams of a combined insecticide and fungicide containing approximately 17 percent of copper and 10 percent of nicotine, the following approximate weights of materials are required:

Grams Copper silicate (containing 19 percent of copper) 89 Nicotine percent of free alkaloid) 12 or Nicotine sulfate (containing 40 percent of nicotine) 30 The resultant products, nicotine-copper silicates, are bluish-green solids, insoluble in water, stable to sunlight, and readily suspended in water. When dry, they are capable of being ground to very fine dust which is extremely toxic to insects.

When products which are water repellent are desired, about 1 to 5 percent by weight of a soluble alkali salt of a solid monocarboxylic acid (i. e., an acid which is normally solid at ordinary room temperature), as, for example, sodium stearate and sodium palmitate, in solution, is added to and-mixed well with the water suspension of the metal silicate before heating and reacting with the nicotine or nicotine sulfate.

The water-repellent products possess the same characteristics as the water-wettable products,

with the exception that they are not Wet by water without the use of a wetting agent, and when properly applied to foliage are less readily removed by water.

Example II To prepare grams of a product containing approximately 18 percent of zinc and 10 percent of nicotine, the following approximate weights of materials are required:

Grams Zinc silicate (containing 20 percent of zinc) 89 Nicotine (95 percent of free alkaloid) 12 or Nicotine sulfate (containing 40 percent of nicotine) 28 Example III To prepare 100 grams of a product containing approximately 39 percent of mercury and 10 percent of nicotine, the following approximate weights of materials are required:

Grams Mercury silicate (containing 43 percent of mercury) The resulting products, nicotine-mercury silicates, are flesh-colored solids and exhibit the same characteristics of the water-wettable products of Example I. The water-repellent products are prepared in the same manner as described in Example I and possess the same characteristics of the waterrepellent products of Example I.

In preparing the new compositions of matter according to method B, a solution of free nicotine (as the free alkaloid) or nicotine sulfate is first chemically reacted at a temperature of about from 50 to 100 C. with an aqueous solution of a soluble heavy metal salt such as copper sulfate, zinc sulfate, and mercuric chloride, to form a nicotine-heavy metal salt. The salt, in turn, is then chemically reacted at a temperature of about from 50 to 100 C. with a dilute solution of sodium silicate (water glass) in the proper proportions to completely react with the nicotine-heavy metal salt. The resulting slurry is heated to boiling with agitation and kept as nearly neutral as possible, as in method A, by the addition of a dilute solution of sodium silicate if acidic, or by the addition of a solution of the soluble heavy metal salt if alkaline. Boiling for a short time generally improves the physical properties of the final product.

In this method, it is preferable to use the heavy metal sulfates when sufiiciently water soluble,

since the resulting alkali sulfates formed during 7 the chemical reaction are not as injurious to vegetation as are some of the other salts such as the chlorides, if not completely removed from the product by washing. It is to be understood, however, that the invention is not limited to the use of the sulfates only, but any other soluble salt of a heavy metal may be used.

The following examples, in which are indicated some of the materials and the quantities necessary in carrying out method B, are illustrative of the invention:

Example IV To prepare 100 grams of a product containing approximately 17 percent of copper and 10 percent of nicotine, the following approximate weights of materials are required:

Grams Copper sulfate (CuSO4.5H2O) 6'7 Nicotine (95 percent of free alkaloid) 12 Nicotine sulfate (containing 40 percent of nicotine) 30 Sodium silicate (water glass) 130 heating and reacting with the nicotine or nicotine sulfate.

The water-repellent products possess the same characteristics as the water-wettable products except that they are not wet by Water without the use of a wetting agent, and when properly applied to foilage are less readily removed by water.

Example V To prepare 100 grams of a product containing approximately 18 percent of zinc and 10 percent of nicotine, the following approximate weights of materials are required:

Grams Zinc sulfate (ZnSOa'lHzO) 79 Nicotine percent of free alkaloid) 12 or Nicotine sulfate (containing 40 percent of nicotine) 28 Sodium silicate (water glass) 130 Example VI To prepare grams of a product containing approximately 39 percent of mercury and 10 percent of nicotine, the following approximate weights of materials are required:

Grams Mercuric chloride (HgClz) 4'7 Nicotine (95 percent of free alkaloid) 11 or Nicotine sulfate (containing 40 percent of nicotine) Sodium silicate (water glass) The resulting products, nicotine-mercury silicates, have the same properties as the Waterwettable products of Example III.

Water-repellent products are prepared in the manner outlined under Example IV and exhibit the same properties as the water-repellent products of that example.

The products obtained by either of the aforementioned methods of preparation are filtered, dried, and then ground to a very fine dust, the smaller the particle size the greater the toxicity to insects and the greater the foilage coverage.

It may be noted that sodium silicate, known as water glass, is not a definite compound and. may vary from a ratio of $102 to NazO of 1 to 4. Mineral Resources of the United States. 1918. Pt. II, p. (G. F. Laughlin). However, other references assign to it the formula Na2Si4O9, with a molecular weight of 302.23. Handbook of Chemistry and Physics. Hodgman-Lange, 15th ed., 1941-1942, p. 458. The sodium silicate used in the present invention gave a copper salt containing 22.3 percent copper, the theoretical copper content for a compound of the formula CuSiiOg being 19.8 percent.

Having thus described my invention, I claim:

1. A process of preparing a nicotine-heavy metal silicate having water-repellent properties comprising mixing a heavy metal silicate selected from the group consisting of copper silicate, zinc silicate, and mercuric silicate, with a solution of about from 1 to 5 percent by weight of a soluble alkali metal salt of a solid monocarboxylic acid