US2469868A - Production of heavy metal nicotine silicates - Google Patents

Description

Patented May 10, 1949 PRODUCTION OF HEAVY METAL N ICOTINE .SILICATES Frederick E. Dearborn, Washington, '1). I).

No Drawing. Original application November a,

1945 Serial No. 627,270. Divided and this application .May .16, 1947, Serial No.748,644

(Cl. 26,0--L2710) (Granted under the act of March 3, 1883,, as amended April 30, 1928,; 3.70 0. .G. 757) 4 Claims.

This applicationissma'de under the: act :of March 3, 1883, as amended by the act of April :30, 1928, and the invention herein described, -if patented, may be manufactured :and used by or for the Government of the United States of America for governmental purposes without the payment to me of any royalty thereon.

This application is a division of my copending application for :patent, Serial No. 627,270, filed November 7, 1945, now Patent 2,466,157, April 5, I949.

Thisinvention relates-to'compositionsof -matter "having combined'insecticidal and fungicidal properties and to processes for making the same, and it has as its prime object the provision of such new compositions which'contain fixed nicotine as the principaltoxic ingredient.

Another object of the invention is to provide such compositions'which-are moretoxic to insects "than nicotinealone and which can The applied to vegetation either as a spray or as a dust without causing injury'to plants.

A --further object is to stabilize the nicotine against'the destructive action of sunlight andthe leaching efiect o'f rain'when'thecompositions are applied to vegetation, thus prolonging \their usefulness.

Cther objects will .be "apparent from the ..de- "scription of the'invention.

It iswell known that nicotine, while .being a highly efiicient. insecticide, both as :a .contact. and as astomach poison, does not possessanyiungicidal properties. Furthermore, nicotine is not stable against the destructive action of sunlight,

which, through its ultra-violetand visible short 7 metal silicates.

2 negating the leaching efiect of rain or other sources of Water.

i ne. and many .of its salts suchas nicotine sulfate, combines with certain heavy metallic salts such as copper, zinc, mercury, and others, to form complex salts (see ,Compt. Bend. ,Acad. Sci. (Paris) 141.224 226; 1.842) and their toxicity both as aoontact and as a stomach poison, are appreciably increased when in chemical .combination withsuchheav-y zmetallicsalts. This has been shown .by .tests made against ,the cockroach and the codling moth larvae.

Copper. in numerous insoluble or slightly soluble compounds, has long been recognized as a .highly eflicient fungicide :and has .been extensively used as such. Recently, zinc compounds have been used effectively againstcertain iungi. .Mercur-y {compounds are well known bactericides -and fungicides, and have ,also been extensively '.-used.

In the present invention, insoluble heavy metal salts such as copper, :zinc, and mercury silicates, are chemically combined with nicotine in anoyel manner to yield new complex nicotine-heavy These nicotine-heavy metal silicates have :combined :insecticidal and fungi- ,cidal properties in which the toxicity of the nicotine bothasa con-tactand as-a-stomach poison is appreciably increased, -.the nicotine is stabilized against the destructive :rays of "the sun, and the product itself :may :be suspended ,in water :or ground to a fine dust and applied either as a lsprayor-as'adust to vegetation without causing (any injury to the plants. furthermore, as men- :tioned above, the product, in addition to having :the above properties, :may -1be rendered water -re- ;pellent by a process :to be vlater described. "The ;-pr.0.d:.ucts of the invention :are superior to the lordinarymechanical-mixture of a nicotine preparation and 1a 10013138! fungicide, :for example. :Such :a mixture has a greatly reduced toxicity 'ivhemapplied to'rvegetationzeither as aspray-or asaa dust,-and causes considerable 'foliage injury. That this is the casewas shown :when such a mechanical mixture was applied to apple-tree foliage in tests conducted against the codli-ng :moth.

The compositions 50f tires-invention, which are "insoluble ,nicotineeheavy :metal silicates, such as micotina-rcopper :silicate, inicotiner-zinc silicate,

and nicotine-mercury silicate, can be prepared by either of two methods hereinafter designated as method A and method B.

Method A involves chemically reacting a water suspension of an insoluble heavy metal silicate prepared by chemically reacting a soluble, substantially pure sodium silicate such as water glass with a soluble heavy metal salt such as copper sulfate, zinc sulfate, or mercuric chloride) with a solution of free nicotine (present as the free alkaloid), or nicotine sulfate. Method B involves chemically reacting a soluble nicotine 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, without 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, sodium 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 13, 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 incon- 4 venient, 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 loss of nicotine and, in some cases, the formation of the metallic oxide, especially when a copper salt is used.

The resulting products are insoluble solids, stable to sunlight and readily wet by water. When dry, they are capable of being ground to a very fine dust which has highly combined insecticidial and fungicidal properties.

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

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 4i) 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 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 The resulting products, nicotine-zinc silicates, are cream to light brown, in color, and exhibit the same characteristics of the water-wettabl products of Example I.

The water-repellent products are prepared in Examp III To prepare 100 grams of a product containing te 39 cent o e -w nd it g appn me rai Mercpry silicate (containing 9 3, percent of mercury) Nicptirie 1 9,5, percent of freed)"; v

or Nicotine sulfate (containing 40 percent of 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 soluble nictotine-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 suificiently water soluble, since the resulting alkali sulfates formed during 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) 67 Nicotine (95 percent of free alkaloid) 12 or Nicotine sulfate (containing percent of nicotine) 30 Sodium silicate (water glass) 130 The resulting products, nicotine-copper silicates, have the same properties as the water-wetta'ble products of Example I.

=6 p ec nct 1e -siraree in he bed under xampl the use a wetting agent, and hen prope y @P 199 9 11.95? W 6. readily removed by Et mple V 50 p epare .100 gram of a ro uct. con a nin ep m' a ql 1.3. perc nt. o zi a 1.0 percent c ce). the fiollqwin app o i a e e hts of m ter als a e r qu e Grams sulfate nso4fl. ao rrr-r-r. Nicotine percent'of free alkaloid) 12 Nicotine sulfate (containing 40 percent of nicotine) Sodium silicate (water glass) 130 Example VI To prepare grams of a product containing appproximately 39 percent of mercury and 10 percent of nicotine, the following approximate weights of materials are required:

Grams Mercuric chloride (HgClz) 47 Nicotine (95 percent of free alkaloid) 11 or Nicotine sulfate (containing 40 percent of nicotine) 26 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 foliage coverage.

It may be noted that sodium silicate, known as water glass, is not a definite compound and may vary from a ratio of SiOz to NazO of 1 to 4. Mineral Resources of the United States. 1918. Pt. II, p. 190. (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 CuSi4O9 being 19.8 percent.

Having thus described my invention, I claim:

1. A process comprising reacting a soluble nicotine-heavy metal salt, wherein the heavy metal is selected from the group consisting of copper, zinc, and mercury, with substantially pure sodium silicate in a substantially neutral aqueous medium at a temperature of about from 50 to 100 C. to form a nicotine-heavy metal silicate.

2. A process comprising reacting a soluble nicotine-copper salt with substantially pure sodium silicate in a substantially neutral aqueous medium at a temperature of about from 50 to 100 C. to form a nicotine-copper silicate.

3. A process comprising reacting a soluble nicotine-zinc salt with substantially pure sodium silicate in a substantially neutral aqueous medium at a temperature of about from 50 to 100 C. to form a nicotine-zinc silicate.

4. A process comprising reacting a soluble nicotine-mercuric salt with substantially pure sodium silicate in a substantially neutral aqueous medium at a temperature of about from 50 to 100 C. to form a nicotine-mercuric silicate.

FREDERICK E. DEARBORN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Housberry et al., Jour. Econ. Entomol, vol. 34 (1), pp. 80-83 941).

Markwood, Jour. Assoc. Ofi. Agric. Chemists, vol. XXV (2), pp. 474-478 (1942).