US3519414A - Algaetoxic,synergistic compositions of aza - 1 - cycloheptenes and quaternary ammonium compounds and method of use - Google Patents

Description

United States Patent US. Cl. 7167 20 Claims ABSTRACT OF THE DISCLOSURE A new class of algaecides is described. They have the formula CHz-CHz RNH-(I? CH2 NCH2-(JH2 wherein R is an alkyl group having from 10 to 18 carbon atoms; and addition salts thereof.

Also described is the synergistic effect that 2-laurylamino-l-aza-l-cycloheptene and Z-tetradecylamino-l-azal-cycloheptene, and their respective addition salts with inorganic and organic acids and phenols, exhibit with numerous quaternary ammonium compounds.

This invention relates to the use of certain compounds for the purpose of preventing the development of algae. More particularly, this invention relates to the algaetoxic use of compounds having the formula:

wherein R is an alkyl group having from 10 to 18 carbon atims; and addition salts thereof.

The cycloheptene compounds of the present invention have been found to possess high levels of algaetoxic activity, in the form of solutions, emulsions or suspensions. Solvents such as acetone, isopropanol and propylene glycol, per se or in admixture with each other or with other liquids such as water, may be used to form solutions. Dispersions or emulsions with water or other non-solvents for the compounds can be used, if desired.

Also, if desired, the compounds of this invention may be employed along with any conventional ingredients, for example, with other substances having microbiological activity, such as other algaestats or algaecides.

For practical use as algaetoxic agents, the compounds of this invention may be formulated with or without conventional carriers to obtain the desired concentrations and to facilitate use. In use, the algaetoxic agents or suspensions, emulsions or solutions thereof are added to the water system to be protected,. Streams, ponds, swimming pools, water cooling towers, irrigation ditches and reservoirs are examples of water systems which can be protected with the active algaetoxic agents of this invention.

So far as concerns the amount of algaetoxic agent to be employed, this is subject to various considerations, such as the type of water to be treated. Generally, as little as 5 mcg./ml. will be suflicient to inhibit the growth of algae. In any event, it will be understood by those skilled in the art that a quantity of'algaetoxic agent, sufficient to yield at least the minimal inhibitory concentration of agent in the water system to be protected, should be used.

In addition to the unexpected and unobvious algaetoxic properties of the compounds of this invention, a further ice surprising finding has been made by us. We refer to the finding that 2- laurylamino-l-aza-l-cycloheptene and Z-tetradecylamino-l-aza-l-cycloheptene, and their respective addition salts with inorganic and organic acids and phenols, have the property of exhibiting synergistic algae toxic effects with certain quaternary ammonium compounds. The quaternary ammonium compounds referred to are the following:

Class 1: quaternary compounds having the following structural formula:

N R CH 8 wherein R is an alkyl group having from about 12 to 20 carbon atoms and X is a halogen;

Class 2: quaternary compounds formed from benzyl halide and a compound having the structural formula:

?H2CH2OH /NCH2 RC N-CH:

where R is a member selected from an alkyl group having from about 8 to 18 carbon atoms and an alkylene group having from about 8 to 18 carbon atoms;

Class 3: quaternary compounds having the structural formula:

CH3 R OHzC Hs wherein R is an alkyl group having from 12 to 16 carbon atoms and X is a halogen; and

Class 4: quaternary compounds having the structural formula:

R3N X- wherein R is an alkyl group having from 12 to 16 carbon atoms and X is a halogen.

The quaternary compounds useful in accordance with this invention are viscous to solid, colorless to amber-like and soluble in water and the common alcoholic solvents, such as ethyl alcohol. The Class 1 quaternaries are soluble in petroleum ether; whereas, the others are not.

Compositions containing the cycloheptene agents of this invention and the aforeindicated quaternary compounds are prepared and used in substantially the same manner as the compositions without the quaternary compounds.

The ratio of cycloheptene to quaternary compound may vary over wide limits. We have found that a range of ratios of 16 to l to 0.12 to 1 by weight of the cycloheptene to that of the quaternary compound exhibits a synergistic activity. Higher or lower ratios could be used but the activity would probably represent the activity of the larger active component in the system. We presently prefer to use a ratio of 1 to 1.

Solutions of the cycloheptene and quaternary compound, for example, in alcohol, are colorless to light amber in color depending upon the concentrations of these materials. Mixtures of the cycloheptene and quaternaries themselves, are generally viscous, when freshly-prepared, but solidify partially or completely, on standing at ambient room temperatures over a period of a week or more. Some mixtures are solid even when freshly prepared. The mixtures are water-White to amber in color and soluble in water and common alcoholic solvents. Mixtures of Class 1 quaternaries and cycloheptene compounds are completely soluble in petroleum ether, whereas the other mixtures are not soluble in that solvent.

In order to illustrate the algaetoxic activity of the compounds falling within the scope of this invention, there is presented below a series of test results. It is understood that these results are reported solely by way of illustration and are not in any way intended to be construed as a limitation of the present invention. All degrees are Centigrade unless otherwise stated.

Algaestatic tests were conducted using Chlorella vulgaris ATCC 9765 and ChlamydOmonas pseudaglo'e ATOC 12235 as test organisms. Both organisms were grown in ATCC peptone broth and Allens medium continuously illuminated with 150 foot candle light from a 30 watt, cool white, fluorescent (Gen. Electric) tube for a period of 30 days. The temperature of incubation was 25 C. Dilutions of compounds in broth were accomplished by first preparing two-fold serial alcoholic dilutions from 0.1% alcoholic solutions of test compounds. Aliquots (0.1 m1.) of the alcoholic two-fold serial dilutions were added to 50 ml. Fernbach fiasks containing 20 ml. of culture media. Inocula were prepared from seven day old ATOC peptone broth cultures by diluting with the same sterile broth to transmittance (530 mu) in a Lumetron colorimeter, model 401A. Each test flask received one drop (0.05 ml.) of inoculum. Flasks were incubated for 30 days and the minimal inhibitory concentration of the two-fold serial concentration series recorded as shown in Table I below.

lllll++++ EXAMPLE 10 No. 3231 N alguat G-8-11:

lllll+ lllll++ llll|l++ TABLE I..ALGAESTATIO (MINIMAL INHIBITORY CONCENTRATIONS) OF AZA- GYCLOHEPTENE DERIVATIVES. (MCG./ML.).

Chlorella. Chlamydomonus vulaaris pseudagloe Example No. Allens A.T.C.C. Allen's 1 A.'I.C.C.

1 2-decylamlno-l-aza-l-cycloheptene 2. 5 2. 6 5. 0 2. 5 2 Z-tetradecylamino-1-aza-1-cycloheptene 2. 5 2. 5 2. 5 2. 5 3 2-hexadecylamino-l-aza-l-cycloheptene 2. 5 2. 5 2. 5 2. 5 4 2(1-methyldecylamino)-1-aza-1-oycloheptene 2. 5 2. 5 2. 5 2. 5 5 2-laurylamino-1aza-1-cycloheptena 1. 25 1. 25 1. 25 1. 6.. 2-octadecylamino-1-aza-1-cycloheptene 5. 0 5. 0 5. 00 5. 00

l ATCC broth=Yeast ext. (Dlfco) 1 g.; Beef ext. (Difco) 1 g.; Tryptose (Diico) 2 g.; Glucose 10 g.; to 1,000 m1.

dist. water, pH 7 5 Allen's mediuin=Allen, M. 13., Archiv nu Mikrobiologie, news 1952).

Examples 7-11, inclusive, give data showing the inhibitory concentrations of 2-laurylamino-l-aza-cycloheptene and Z-tetradecylamino-l-aza-cycloheptene, per se, and in Hyaomine 3500:

lllll+ Illl-lilll-l- III- EXAMPLE 11 N 0. 4258 Hyanine 3500:

lllll'illlll+++ In order that Examples 7-11, inclusive, may be easily and fully understood, the following codes are given:

No. 3231 is 2-laurylamino-l-aza-l-cycloheptene.

No. 4258 is Z-tetradecylamino-l-aza-l-cycloheptene.

Acetoquat CPC is cetyl pyridinium chloride, marketed by Aceto Chemical Co., Flushing, N.Y. It is a white solid, with a melting point of 83 C., and is soluble in water and alcohol but insoluble in petroleum ether.

Cetyl pyridinium bromide has a MP. of 61-62 C. It is soluble in alcohol and dioxane, sparingly soluble in cold water, soluble in water at 30 C. and insoluble in petroleum ether.

Hyamine 3500 is a mixture of N-alkyl dimethyl benzylammonium chlorides, marketed by Rohm & Haas, Philadelphia, Pa. The alkyl groups contain from 12 to 16 carbon atoms. This product is available commercially as a 5 and solution in Water and alcohol, The

quaternary compound is obtained by evaporating the solvents on the steam bath. The product is a nearly colorless soft, slightly tacky, very viscous material which is soluble in alcohol and water, and insoluble in petroleum ether.

Isothan DL-l is a mixture of dialkyl dimethyl ammonium bromides, marketed by Onyx Chemical Co., Jersey City, NJ. The alkyl groups contain from 10' to 16 carbon atoms in the ratio in which they are derived from the fatty acids present in coconut oil. This product is available commercially as a 75% solution in isopropanol. The quaternary compound was obtained by evaporating the solvent on the steam bath. It is a soft, very viscous material, soluble in alcohol and water, and in petroleum ether.

Nalquat G8-11 is a mixture of 1-(2-hydroxyethyl)-2- alkylimidazolines, quaternized by means of benzyl chlo ride, marketed by Nalco Chemical Co., Chicago, Ill. The alkyl groups contain from 11 to 17 carbon atoms. This product is available as a 60% solution and the quaternary compound is obtained by evaporating the solvent on the steam bath. The compound is a nearly colorless to amber, very viscous material, soluble in alcohol and water but insoluble in petroleum ether.

The code identifying the concentrations represented by integers from to 8 in Examples 7-11, inclusive, is given below:

Meg/m1. 8 1O 7 5 6 2.5 5 1.25 4 0.625 3 0.312 2 0.156 1 0.078 0 0.000

For ease of presentation the combinations in Examples 7 to 11, inclusive, are presented in coordinate graphic form with corresponding growth and complete inhibition notations.

A coordinate point (sample preparation) reading Column 4 and Row 5 would correspond to 0.625 meg/ml. of the column component and 1.25 meg/ml. of the row component and a total for the two component mixture of 1.875 meg/ml.

Enhancement action rather than an additive effect may be determined by relating the relative activities of each component in terms of a single component. Thus in the case of the No. 3231 and Hyamine 3500 test, Example 8, it required 2.5 mcg./ml. 3231 and 1.25 mcg./ ml. Hyamine 3500 for complete inhibition of growth. On an activity basis 2.5 3231:;125 Hyamine 3500 or 1 unit Hyamine 350002 units of 3231. The Column 1, Row 1 coordinate sample resulted in complete inhibition in which case the sample contained 0.078 meg/ml. Hyamine 3500 and meg/ml. This corresponds to an approximate (1.25/.117) 11-fold increase in activity for this particular combination.

Active cycloheptenes and quaternary compounds in accordance with this invention may be prepared in accordance with known procedure.

The cycloheptenes may be prepared by condensation of the appropriate alkylamines with O-methylcaprolactim (3,4,5,6-tetrahydro-2H-azepin-7-ol methyl ether), in accordance with the following representation:

As an illustrative example of the preparation of an active cycloheptene we give the following example:

EXAMPLE 12 Preparation of 2-laurylaminol -azal-cycloheptene O-methylcaprolactim (38 g.) and 55 g. of Formonyte D616 (Foremost Food and Chemical Company), a commercial grade of laurylamine were charged into a 250 ml. flask fitted with a sealed stirrer, a thermometer and an adapter connected to a condenser for condensation of the methanol generated during the reaction.

The agitated contents of the flask were heated gradually over a period of seven hours from 138 to 185. About 6.5 ml. of methanol were collected.

The resulting brown oil was distilled at a pressure of 5 mm.

B.P. C. Weight G. (1) 118-200 3.4

(2) 200210 69.4 Residue 6.2

Fraction 2 congealed on standing to a white, soft solid;

AnaIysis.Calcd. for C H N (percent): C, 77.07; H, 12.94. Found (percent): C, 77.31; H, 12.90.

The compound is soluble in isopropanol and acetone. It disperses in water; such dispersions froth abundantly. Solutions in dilute acids are excellent foamers.

The hydrochloride of the compound is a white, crystalline solid; M.P. 148-149.

Analysis.-Calcd. for C1 H3 1N2Cl (percent): C, 68.21; H, 11.77; Cl, 11.19. Found (percent): C, 67.96; H, 11.72; Cl, 11.13.

Solutions of the hydrochloride in water foam.

Following the above procedure, in general, the other active cycloheptenes were prepared, with the characteristics as noted in Table 2.

TABLE 2 Physical appear- Analysis ance of the freshly C.P., Compound distilled product; B.P., C. 0. mi Percent Calcd. Found 2-de0y1amino-l-aza-l-cycloheptene Oil 185-189/5mm 1. 4905 g 73.12 33 1 .78 1 Q-(l-methyldecylamino)1aza-1-cycloheptene Oil 164-190/3nm1 1. 4872 76.62 72.51 12. 86 1 51 2-tetradecylamino-l-aza-1-cycloheptene Solid 205-220/3 111111.- 61 7g. 1 2-hexadecylamino-l-aza-1-cycloheptene do 230245/3 mm 54 ..{g[ 73.50 7%. 1 l8 1 Z-Qctadeeylamino-l-aza-l-cycloheptene .do 1 -72 X Melting point.

0.078 meg/ml. 3231 and a total of 0.156 meg/ml. total active component. In terms of Hyamine 3500 then this Salts of the active cycloheptenes of this invention may be prepared by dissolving equimolecular amounts of the sample contained 0.078 mcg./ml.+0.039 mcg./ml.=0.l17 azacycloheptenes and an inorganic acid, or an organic acid, or a phenol, including bis-phenols, in about a threefold amount of methanol, ethanol or isopropanol. In the case of bisphenols the ratio of the azacycloheptenes to bis-phenol can be 1:1 or 2:1.

The solvent is removed on the steam bath or under reduced pressure, leaving the salts as oily or resinous or crystalline products, which, in certain cases, can be rec ystallized.

Examples of inorganic acids: hydrochloric acid, sulfuric acid, phosphoric acid.

Examples of organic acids: acetic acid, lactic acid, benzoic acid.

Examples of phenols: 2,4,5-trichlorophenol, p-chlorom-xylenol, hexylresorcinol.

Examples of bis-phenols: 2,2'-methylenebis-(4-chlorophenol), 2,2'-methylenebis(4,6-dichlorophenol), 2,2- methylenebis (3,4,6-trichlorophenol, 2,2'-thiobis (4,6-dichlorophenol) Detailed description for the preparation of representative salts is given below in Examples 13-16, inclusive.

EXAMPLE 13 Z-Iaurylamino-l-aza-l-cycloheptene hydrochloride 2-laurylamino-l-aza-l-cycloheptene (8.4 g.) ice-water (60 g.), alcohol (30 ml.) and cone. hydrochloric acid 38% (4 g.) were mixed in a beaker. The resulting solution was poured into a dish and the solvents were allowed to evaporate spontaneously overnight. A white solid resulted which was freed of adhering moisture by suction filtration. It was dried at a pressure of 4 mm. at room temperature. The hydrochloride was recrystallized from a mixture of hexane and isopropanol. The recrystallized material had a M.P. of 148-149.

It is difiicultly soluble in water at room temperature and readily soluble in acetone.

EXAMPLE 14 Acetic acid salt of 2-laurylamino-1-aza-l-cycloheptene 2-laurylamino-1-aza-1-cycloheptene (1.4 g.) was dissolved in 5'ml. of methanol; glacial acetic acid (0.3 g.) was added. The resulting solution was freed of the solvent on the steam bath. The acetic acid salt resulted as a heavy oil of a slightly amber color. It is soluble in water; these solutions froth abundantly. It is soluble in ethanol, isopropanol and insoluble in petroleum ether.

EXAMPLE 15 Salt of 2-laurylamino-l-aza-l-cycloheptene with 2,4,5-trichlorophenol 2-laurylamino-l-aza-l-cycloheptene (0.7 g.) and 2,4,5- trichlorophenol (0.5 g.) were dissolved in 5 ml. of methanol. The solution was freed of the methanol on the steam bath. The resulting salt is a tacky, slightly colored resin. It is insoluble in water and soluble in isopropanol.

EXAMPLE 16 Salt of 2-laurylamino-l-aza-l-cycloheptene with 2,2- methylenebis(3,4,6-trichlorophenol), G-11 2-laurylamino-l-aza-l-cycloheptene (0.7 g.) and 6-11 (1.02 g.) were dissolved in 5 ml. of methanol. The solution was freed of the methanol on the steam bath. The resulting salt is a hard, yellowish resin, insoluble in water and soluble in isopropanol.

Substitution of the salts of the active aminocycloheptenes in any of the foregoing examples results in substantially the same algaetoxic effects as those secured with the corresponding aminocycloheptenes.

Quaternary compounds useful in accordance with this invention may be prepared by reaction of the suitable tertiary amines with the appropriate halo compounds.

The reaction is carried out preferentially at elevated temperatures of about 50-150 in the absence, or in the presence, of solvents. Eventually, the condensation is allowed to take place in an autoclave, especially when halo compounds with low boiling points, are being employed. Usually, the yields are quantitative or nearly quantitative. No further purification is necessary for the intended uses although in the cases of solid reaction products crystallization is possible.

Examples 17-20, inclusive, give details of the preparation of specific members of the aforementioned four classes of quaternary compounds, each preparation being typical of the class.

EXAMPLE 17 Class 1.Dilauryldimethylammonium bromide (corresponding to Isothan DL-l l-bromododecane (9.9 g.) and N,N-dimethyl-1-aminododecane (8.5 g.) were agitated and heated at 110-115 for minutes. A soft, slightly yellowish solid resulted. It is soluble in water. Concentrated solutions are hazy; dilute solutions are limpid. These solutions froth abundantly.

EXAMPLE 18 Class 2.1-(2-hydroxyethyl-1 (or 3 )-benzyl-2- undecylimidazolinium chloride EXAMPLE 19 Class 3.-Lauryldimethylbenzylammonium chloride This compound was prepared according to 0. Westphal and Dietrich Jerchel, Ber. 73 B, 1002.

l-chlorododecane (17.6 g.), N-dimethylbenzylamine (11.8 g.) and 10 ml. of alcohol were agitated and heated for 45 hours at 90. The alcohol was then distilled in vacuum. The residue was dissolved in hot ethyl acetate and the quaternary salt was precipitated by ethyl ether. Yield: quantitative. The compound is a very tacky oil, soluble in water, dilute acids and dilute alkali.

EXAMPLE 20 Class 4.Cetylpyridinium chloride This compound was prepared according to P. Karrer et al., Helv. Chim. Acta, 21, 233 (1938).

Tenth molar amounts of pyridine and l-chlorohexaadecane were heated in an autoclave for 15 hours at After cooling, the crystals were filtered and washed with ether; M.P., after recrystallization from benezene, 83.

Examples 21-24, inclusive, give illustration examples of specific typical synergistic compositions of this invention.

EXAMPLE 21 One gram of 2-laurylamino-1-aza-1-cycloheptene and one gram of cetylpyridinium chloride were mixed and finely ground in mortar. A white solid resulted; M.P. starts to sinter at about 47; melts at about 75. The mixture is soluble in alcohol, propylene glycol, and in water; partially soluble in petroleum ether.

9 EXAMPLE 22 One gram of 2-laurylamino-1-aza-1-cycloheptene and one gram of the compound contained in Hyamine 3500 were dissolved in 5 ml. of methanol and concentrated to dryness on the steam bath.

The resulting mixture is a very viscous oil, changing slowly to an oily solid. It is soluble in water; concentrated solutions are turbid; dilute solutions are limpid; it is partially soluble in petroleum ether at room temperature; solutions in alcohol or isopropanol are clear.

EXAMPLE 23 One gram of Z-laurylamino-l-aza-l-cycloheptene and one gram of the compound contained in Nalquat G811 were dissolved in 5 ml. of methanol. The solvent was evaporated on the steam bath. The remaining product is a viscous oil, changing slowly to an oily solid.

Solutions in alcohol, isopropanol or propylene glycol are clea'. Depending on the concentration, solutions in water are turbid or clear. The mixture is not soluble in petroleum ether.

EXAMPLE 24 Oneg ram of 2-laurylamino-l-aza-l-cycloheptene and one gram of the compound contained in Isothan DL-l were dissolved in 5 ml. of methanol. The solvent was evaporated on the steam bath. The remaining product is a viscous, nearly colorless oil, changing slowly to an oily solid. It is clearly soluble in alcohol, propylene glycol or isopropanol. Concentrated solutions in water are turbid; dilute solutions are very slightly hazy. It is soluble in petroleum ether.

The solut ons of the products of Examples 21 to 24, in water, froth abundantly. Turbid or hazy solution can be made limpid by the addition of small amounts of acids, as for instance acetice acid.

In general, mixtures of the azacycloheptenes with the quaternary ammonium compounds with a diiferent ratio then 5:5, as for instance 1:9 or 9.1 have properties similar to those described above.

The foregoing illustrates the practice of this invention, which, however is not to be limited thereby, but is to be construed as broadly as permissible in view of the prior art and limited solely by the appended claims.

What is claimed is:

1. A method for preventing the development of algae, which comprises applying to the locus to be protected an algaestatically effective amount of a member selected from the group consisting of (a) a quaternary compound having the following structural formula:

R CH3 1 R/ CHa wherein R is an alkyl group having from about 12 to 20 carbon atoms and X is a halogen;

(b) A quaternary compound formed from benzyl halide and a compound having the structural formula:

where R' is a member selected from an alkyl group having from about 8 to 18 carbon atoms and an alkylene group having from about 8 to 18 carbon atoms;

wherein R is an alkyl group having from 12 to 16 carbon atoms and X is a halogen; and

wherein R is an alkyl group having from 12 to 16 carbon atoms and X is a halogen, in synergistic admixture with a cycloheptene selected from the group consisting of 2-lauryl-amino-1-aza-l-cycloheptene, and acid addition salts or phenol addition salts thereof.

2. The method of claim 1, wherein the cycloheptene is selected from the group consisting of Z-tetradecylaminol-aza-l-cycloheptene and its acid addition salts or phenol addition salts thereof.

3. The method of claim 1, wherein the quaternary compound is a mixture of dialkyl dimethyl ammonium bromides having from 12 to 16 carbon atoms in the alkyl groups and the cycloheptene is 2-laurylamino-1-aza-1- cycloheptene.

4. The method of claim 1, wherein the quaternary compound is a mixture of 1-(2-hydroxyethyl)-2-alkylimidazolines having from 11 to 17 carbon atoms in the alkyl group, quaternized by means of benzyl chloride, and the cycloheptene is 2-laurylamino-l-aza-l-cycloheptene.

5. The method of claim 1, wherein the quaternary compound is a mixture of N-alkyl dimethylbenzyl ammonium chlorides wherein alkyl has from 10 to 16 carbon atoms and the cycloheptene is 2-laurylamino-l-azal-cycloheptene.

6. The method of claim 1, wherein the quaternary compound is cetyl pyridinium chloride and the cycloheptene is 2-laurylamino-l-aza-l-cycloheptene.

7. The method of claim 2, wherein the quaternary ammonium compound is a mixture of dialkyl dimethyl ammonium bromides having from 12 to 16 carbon atoms in the alkyl groups, and the cycloheptene is Z-tetradecylamino-l-aza-l-cycloheptene.

8. The method of claim 2, wherein the quaternary compound is a mixture of l-(2-hydroxyethyl)-2-alkylimidazolines having from 11 to 17 carbon atoms in the alkyl groups, quaternized by means of benzyl chloride, and the cycloheptene is Z-tetradecyl-l-aza-1-cycloheptene.

9. The method of claim 2, wherein the quaternary compound is a mixture of N-alkyl dimethyl benzyl ammonium chlorides having from 10 to 16 carbon atoms in the alkyl group, and the cycloheptene is Z-tetradecylamino-1-aza-1-cycloheptene.

10. The method of claim 2, wherein the quaternary compound is cetyl pyridinium chloride and the cycloheptene is Z-tetradecylamino-l-aZa-1-cycloheptene.

11. A composition for preventing the development of algae, which comprises the synergistic admixture set forth in claim 1.

12. A composition for preventing the development of algae, which comprises the synergistic admixture set forth in claim 2.

13. A composition for preventing the development of algae, which comprises the synergistic admixture set forth in claim 3.

14. A composition for preventing the development of algae, which comprises the synergistic admixture set forth in claim 4.

15. A composition for preventing the development of algae, which comprises the synergistic admixture set forth in claim 5.

16. A composition for preventing the development of algae, which comprises the synergistic admixture set forth in claim 6.

17. A composition for preventing the development of algae, which comprises the synergistic admixture set forth in claim 7.

18. A composition for preventing the development of algae, which comprises the synergistic admixture set forth in claim 8.

11 12 v 19. A composition for preventing the development of 3,197,495 7/1965 Strycker -..'.J' 260-440 algae, which comprises the synergistic admixture set forth 1 3,130,124 .4/ 1964 Ferris et a1. 16742 in claim 9. 1 I

20. A composition for preventing the development of FOREIGN, A EN algae, which comprises the synergistic admixture set forth 5 774,111 9 Ca da. in claim 10, 1, 1,367,799 6/1964 France.

' References Cited UNITED STATES PATENTS 3,212,963 10/1965 Wehner "167-22 10 3,201,593 9/1965 Lindaberry 71-67 US. 01. x11. 3,200,128 8/1965 Wagner 260296 71-88, 121

GOT TS, Primary Examiner c. L. MILLS, Assistant Examiner