WO2000069778A1

WO2000069778A1 - Methods of using percarboxylic acid or anions thereof and methods of making the same

Info

Publication number: WO2000069778A1
Application number: PCT/US2000/012711
Authority: WO
Inventors: Percy A. Jaquess
Original assignee: Buckman Laboratories International, Inc.
Priority date: 1999-05-17
Filing date: 2000-05-10
Publication date: 2000-11-23
Also published as: AU4998100A; WO2000069778A9

Abstract

A method to produce percarboxylic acids and/or percarboxyl anions, such as peracetic acid and/or peracetyl anions, is described as well as use of such a system to treat or control the growth of at least one microorganism in aqueous systems such as paper and pulp manufacturing systems, cooling water towers, swimming pools, jacuzzis, hot tubs, ponds breweries, pasteurization systems and the like. The system involves reacting in an aqueous solvent, a sulfate containing reactant with an acid generating acyl activator, like tetraacetylethylenediamine, to form a product comprising percarboxylic acid and/or percarboxyl anions, like peracetic acid and/or peracetyl anions. Methods to control at least one microorganism using the system are further described.

Description

METHODS OF USING PERCARBOXYLIC ACID OR ANIONS THEREOF AND METHODS OF MAKING THE SAME

BACKGROUND OF THE INVENTION The present invention relates to reactions which produce percarboxylic acid and/or anions thereof. The present invention further relates to a variety of methods for using percarboxylic acid and the anions thereof in a variety of applications. Further the present invention relates to controlling the growth of a variety of microorganisms.

Biological fouling is a serious economic problem in many commercial and industrial aqueous processes and water handling systems. The fouling is caused by a biomass which is the build up of microorganisms and/or extracellular substances and by dirt or debris that become trapped in the biomass. Bacteria, fungi, yeast, diatoms, and protozoa are only some of the organisms which can cause buildup of a biomass. If not controlled, the biofouling caused by these organisms can interfere with process operations, lower the efficiency of the processes, waste energy, and reduce product quality.

Cooling water systems used in power-generating plants, refineries, chemical plants, air conditioning systems, and other commercial and industrial operations frequently encounter biofilm problems. Biofilm is the buildup of layers of organisms. Cooling water systems are commonly contaminated with airborne organisms entrained by air/water contact in cooling towers as well as waterborne organisms from the systems makeup water supply. The water in such systems is generally an excellent growth medium for these organisms. If not controlled, the biofilm biofouling resulting from such growth can plug towers, block pipelines, and coat heat transfer surfaces with layers of slime, and thereby prevent proper operation and reduce equipment efficiency. Industrial processes subjected to problems with biofouling include those used for the manufacture of pulp, paper, paperboard, and textiles, particularly water laid non-woven fabrics. For example, paper machines handle very large volumes of water in recirculating systems called '"white water systems." The white water contains pulp dispersions. The furnish to a paper machine typically contains only about 0.5 % of fibers and non- fiberous paper making solids, which means that for each ton of paper, almost 200 tons of water passes through the paper machine, most of it being recirculated in the white water system.

These water systems provide an excellent growth medium for microorganisms which can result in the formation of microbial slime in headboxes. water lines, and papermaking equipment. Such slime and masses not only can interfere with water and stop flows, but, when they break loose, they can cause spots or holes in the paper as well as web breaks which cause costly disruptions in paper machine operations.

Thus, one goal, is to simply control the growth of microorganisms that cause the biofouling since if the control of the microorganisms can be successful, there should be essentially very low biofouling. Aqueous systems, such as emulsions, suspensions, or solutions containing organic material are also highly subject to microbiological attack. Such aqueous systems include dyes, latexes, paint, surfactants, dispersants, stabilizers, thickeners, adhesives, starches, waxes, proteins, emulsifying agents, detergents, cellulose products, resins, metalworking fluids, cooling tower fluids, papermill liquids, tanning liquors, and recreational aqueous systems, i.e., pools, spas, and the like. These systems frequently contain relatively large amounts of water causing them to be well-suited environments for biological growth and thus attack and degradation. Microbiological fouling and degradation of aqueous systems containing organic materials manifest themselves by problems such as loss of viscosity, gas formation, objectionable odors, decreased pH. emulsion breaking, color change, and gelling.

Another objectionable phenomenon occurring in aqueous industrial, commercial, or recreational systems is slime formation. Slime can reduce yields from industrial processes using aqueous systems and render recreational aqueous systems unsuitable for use. Slime consists of matted deposits of microorganisms, fibers, and debris and may be stringy, pasty, rubbery, tapioca-like or hard and may have a characteristic undesirable odor that is different from that of aqueous liquid systems in which it is formed. The microbiological contaminates involved in slime formation are primarily different species of spore-forming and non spore-forming bacteria, particularly capsulated forms of bacteria that secrete gelatinous substances that envelop or encase the cells. Slime microorganisms also include filamentous bacteria, fungi of the mold type, yeast, and yeast-like organisms. The microbiological organisms responsible for biological fouling of various aqueous systems include various bacterial, fungi, mildews, algaes. and the like. To control deterioration or degradation caused by microorganisms, various industrial microbiocides are used. Workers in the trade have continued to seek improved biocides that have low toxicity and are capable of exhibiting a prolonged biocidal effect against a wide variety of microorganisms at normal use. Increasingly, stringent environmental and safety regulations as well as escalating development cost have created a need for new microbicidal agents selected from known safe and economical materials.

In the past, peracetic acid was previously used essentially in the food industries at high concentrations. In the food industries, peracetic acid is used as a sterilant. Until recently, peracetic acid has also been used in combination with other biocides to yield synergistic effects. Peracetic acid has also been an unpopular component in controlling microorganisms especially in industrial water systems due to the significant explosive nature of peracetic acid. At especially high concentrations, peracetic acid can be quite explosive and there have been instances where explosions have occurred. Since peracetic acid is typically transported at high concentrations, users typically introduce high concentrations in their industrial water systems (since trying to dilute peracetic acid can also be a dangerous operation which again can lead to explosions). Thus, those skilled in the art have been quite cautious with the use of peracetic acid as a component in biocides due to this problem.

Accordingly, there is a need to find methods to produce percarboxylic acid, such as peracetic acid, on site in a safe manner and thus avoid the dangers and concerns described above.

SUMMARY OF THE INVENTION

A feature of the present invention is to provide a system which generates percarboxylic acid and/or percarboxyl anions. Another feature of the present invention is to provide a system which has excellent conversion yields in the formation of percarboxylic acid and/or percarboxyl anions. A further feature of the present invention is to provide a system which generates percarboxylic acid and/or percarboxyl anions but does not generate any significant CO? and therefore avoids foaming when introduced to an aqueous system.

An additional feature of the present invention is to provide a system to generate percarboxylic acid and/or percarboxyl anions which addresses the safety concerns which are present when adding percarboxylic acid directly into an aqueous system.

Another feature of the present invention is to provide a variety of applications of the system which generates percarboxylic and/or percarboxyl anions.

Additional features and advantages will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention will be realized and obtained by means of the elements and combinations particularly pointed out in the written description and the appended claims.

To achieve these and other advantages and in accordance with the purposes of the present invention, as embodied and broadly described herein, the present invention relates, in part, to systems which generate percarboxylic acid and/or percarboxyl anions. The percarboxylic acid is preferably a C₂-C₁5 percarboxylic acid or mixtures thereof. More preferably, the percarboxylic acid and/or percarboxyl anion is peracetic acid and/or peracetyl anions. Other examples of percarboxylic acid and/or percarboxyl anions include, but are not limited to. peroctanoic, perdecanoic, and the like. The present invention further relates to a method to produce peracetic acid, peracetyl anions, or both by reacting a sulfate containing reactant with tetraacetylethylenediamine in an aqueous solvent and at a sufficient temperature and in sufficient amounts to produce a product comprising peracetic acid and/or peracetyl anions.

The present invention further relates to a method to produce percarboxylic acid, percarboxyl anions, or both by reacting a sulfate containing reactant with at least one acid generating acyl activator in an aqueous solvent and at a sufficient temperature and in sufficient amounts to produce a product comprising percarboxylic acid, percarboxyl anions. or both. In addition, the present invention relates to a method for controlling the growth of at least one microorganism in an aqueous system involving the step of reacting a sulfate containing reactant with tetraacetylethylenediamine in an aqueous solvent and at a sufficient temperature and in sufficient amounts to produce a product comprising peracetic acid, peracetyl anions, or both and then introducing said product to said aqueous system in an amount effective to control at least one microorganism.

Also, the present invention relates to products formed by the above-described processes, including the percarboxylic and/or percarboxyl anions, and preferably the peracetic acid and/or peracetyl anions and any additional products of the reaction. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present invention as claimed.

DETAILED DESCRIPTION OF THE PRESENT INVENTION The present invention relates, in part, to systems which generate percarboxylic acid and/or percarboxyl anions. The percarboxylic acid is preferably a C2-C15 percarboxylic acid or mixtures thereof. More preferably, the percarboxylic acid and or percarboxyl anion is peracetic acid and/or peracetyl anions. Other examples of percarboxylic acid and/or percarboxyl anions include, but are not limited to, peroctanoic, perdecanoic, and the like. In the system, a sulfate containing reactant is reacted with an acid generating acyl activator, such as acetylsalicylic acid, diacetyl dioxohexahydrotriazine, tetracetyl glycoluril, tetracetyl methylmethylene diamine, pentacetylglucose. tetraacetylethylenediamine (TAED). and the like. Preferably, the acid generating acyl activator is TAED. This reaction produces a product preferably containing diacetylethylenediamine (DAED) and peracetic acid and/or peracetyl anions. The sulfate containing reactant is any sulfur and oxygen containing compound or salt or anion which is capable of reacting with the acid generating acyl activator to form a percarboxylic acid and/or percarboxyl anion. Examples include S-O and S=0 containing groups and the like. More preferably, the sulfate containing reactant can be any sulfate containing compound, salt thereof, or anion which is capable of reacting with TAED to produce peracetic acid and/or peracetyl anions. Preferably, the sulfate containing reactant is an alkali metal persulfate such as, but not limited to, potassium persulfate and/or sodium persulfate. Other examples of sulfate containing compounds or salts thereof include, but are not limited to. sulfolanes. sulfophenyls; sulfoxides; sulfamic acids; sulfanilic acids; and the like.

When a sulfate containing salt is used, the cation can be any cation and preferably is not explosive.

Any amount of the reactants can be used so long as there is sufficient amounts to produce percarboxylic acid and/or percarboxyl anions. Preferably, about 2 moles of the sulfate containing reactant is combined with about 1 mole of the TAED to form about 1 mole of DAED and about 2 mole of peracetic acid and/or peracetyl anions.

As an option, a hydrogen donating species such as an acid like organic acids or mineral acids can be included in the reaction. The hydrogen donating species acts like a catalyst by increasing the conversion yields of the percarboxylic acid and/or percarboxyl anions and further lowers the pH of the mixture containing the reactants. Preferably, the amount of the hydrogen donating species is any amount which will lower the pH and/or increase the conversion yield of the products formed from the reaction. Examples of amounts of the hydrogen donating species is from about 5% by weight based on concentration of dry components to about 50% by weight, and more preferably from about 10% to about 30%, and most preferably from about 15% to about 20% by weight. A preferred hydrogen donating species is citric acid. The hydrogen donating species has the ability to control the speed of the reaction.

The various reactants are commercially available from numerous sources. For instance, the sulfate containing reactant can be obtained from DuPont and the TAED can be obtained from Warwick Chemical, Ltd. Preferably, the concentration of the sulfate containing reactant is from about

10% to about 75% and more preferably from about 20% to about 70% by weight in solution. The concentration of the TAED is from about 10% to about 40% and more preferably from about 15% to about 25% by weight in solution.

The sulfate containing reactant and/or hydrogen donating species have the ability to control the reaction which is advantageous when the reaction is occurring at an end-user site.

In forming the products, the reactants can be introduced to an aqueous solvent and preferably agitated. The reaction can occur at any temperature below the boiling point of the reactants to above the freezing point of the reactant. Preferably, the reaction occurs at ambient temperatures which is quite advantageous for end-user sites.

The reaction can occur in a separate system such as in a vessel and then introduced into the aqueous solution to be treated. This is the preferred manner of forming and introducing the products formed from the reactants. However, it is possible to essentially have this reaction occur in situ in the aqueous system to be treated. The reaction is endothermic which is preferred and advantageous for a variety of reasons.

An advantage of using the sulfate containing reactant and preferably an alkali metal persulfate, is that the reaction does not generate CO2 and therefore does not cause foaming of the aqueous solution. This is quite advantageous at end-user sites since the production of foam is undesirable and can lead to detrimental effects to the products being made such as pulp and paper. Another advantage of the present invention is that the ingredients are preferably solids which can be transported to the end-user site and then added to an aqueous solvent. Further, the system of the present invention preferably kills microorganisms at about 200 ppm or more of the active ingredient and be effective within 10 minutes. Preferred effective concentration ranges include from about 5 ppm to about 3000 ppm or more.

As indicated earlier, an advantage of the present invention is the conversion yields which can be achieved. For instance, when sodium peroxycarbonate or sodium monoperoxyborate is used as a reactant with TAED, conversion rates of from about 10% to about 20% are common. However, when a sulfate containing reactant and especially an alkaline persulfate is used such as potassium persulfate or sodium persulfate, conversion yields on the order of from about 70% to 98% are achieved. In other words, from about 70% to 98% of the TAED is converted to peracetic acid and/or peracetyl anions. This type of conversion makes the reaction quite economical and effective for end-use applications.

The system to generate percarboxylic acid and/or percarboxyl anions can be used in a variety of end-use applications. The conversion yields and the safety considerations provided by this system make it a desirable system to use at end-use applications. Essentially, this system can be used in any system in need of treatment to control the growth of microorganisms. Aqueous systems which can be treated by the present invention, include, but are not limited to, recreational, industrial, and residential aqueous systems. Preferred end-user sites include, but are not limited to, aqueous systems used in the manufacturing of pulp, paper, or paperboard products. The system of the present invention can also be used to treat the aqueous systems used in breweries and other pasteurization systems as well as reverse osmosis systems, holding tanks, cooling towers, swimming pools, hot tubs, Jacuzzis, ponds, and the like. The present invention can also be used with spray washers, water rides, and the like.

In more detail, with respect to pasteurization systems, microbiological control in a water system is very important, since water comes into contact with bottles and cans after they are filled and closed. The system to generate percarboxylic acid and/or percarboxyl anions can be used in such a water system which would be advantageous over current microbicidal systems since the percarboxylic acid and/or percarboxyl anions in the aqueous system would be less corrosive to mild steel and stainless steel unlike the current halogen based treatment programs. Thus, much less system maintenance would be needed since less corrosion would occur in such systems when using the present invention. In addition, with respect to sanitation systems, there is a significant amount of sanitation and cleaning of piping and hoses in such pasteurization operations such as in the production of beer. In fact, almost all piping in such systems are stainless steel and currently caustic cleaning cycles with chlorine based sterilization cycles are used. Unfortunately, the chlorine will degrade and erode the systems over time. The present invention, however, offers much less of a chance for stress corrosion cracking of the stainless steel metals and thus provide a savings with respect to maintenance. In addition, there is a significant amount of line cleanup and filling machine cleanup that can effectively use the systems of the present invention in lieu of chlorine based sanitation regimens. -9- With respect to food processing plants including sugar, poultry, and meat processing operations, general plant sanitation and production line cleaning will benefit from the system of the present invention. In more detail, retort cookers, slicing, and pressing operations use mild steel and thus will obtain a real advantage using the system of the present invention in lieu of chlorine sanitation methods due to the less corrosive nature of the percarboxylic acid and/or percarboxyl anions. Furthermore, dairy operations from the farm to the milk and cheese plants use lots of stainless steel in the processing operations and again the system of the present invention will have the above-identified advantages including minimizing corrosion. In addition, the present invention may have applications with respect to process sanitation which is in direct contact with the food products in the wash water. Furthermore, with respect to additional applications, the present invention has advantages over conventional air washer treatment programs including no smell, less corrosive, no sensitizer issues, and its microbicidal effects over a wide spectrum of microorganisms, including pink slime forming species that are difficult to treat. For instance, the present invention will have these types of advantages in tobacco plants and textile mills and the like. Further, with respect to textile mills and the like, the present invention will provide air charge control benefits that effect textile operations in spinning and weaving operations.

In addition, in certain specialized areas, microbiological control in the textile industry has additional concerns. For example, in nylon and rayon production, the threads are sprayed with water as they leave the spinnerets and thus the potential for slime forming bacteria problems occur. Unfortunately, halogens and quite a few of the non-oxidizers damage the thread strength. The system of the present invention can provide the necessary control of microorganisms and yet not effect the thread strength or other qualities of the synthetic and natural fibers being processed.

With respect to cooling towers and closed loop water systems, again, the present invention's treatment system will provide a less corrosive and more environmental friendly treatment from a discharge permit view point.

With respect to ice making plants and ice machines which are prone to pink slime formation, again, the treatment system of the present invention will provide a highly effective treatment against these species with the above-identified advantages.

With respect to oil and petrochemical processing, again metal working fluids are used and the control of microorganisms are always a goal. Further, microbiological growth in oil storage tanks, in particular, in crude and #4, 5, and 6 fuel oils can be a problem. Also, microbiologically induced corrosion problems with down holes for oil production as well as pipeline corrosions are concerns. Again, the system of the present invention can be effective in controlling microorganism growth without corrosion concerns.

Finally, with respect to hospitals, hotels and other buildings, which use humidification sprays in the HVAC ducts, again, the system of the present invention will provide an effective means of controlling the growth of microorganisms without the corrosion concerns and odor concerns.

In any of these applications, it is preferred that the reactants are combined first with or without the optional hydrogen donating species to form the products wherein the reaction occurs in an aqueous solvent, such as water. Once the reaction is completed, then preferably the solution is introduced into the aqueous system to be treated. The manner in which the products formed from the reaction are introduced can be by any conventional means of introducing a solution into an aqueous system such as, but not limited to. pouring or by metering with a suitable device.

Besides the products from this reaction, other components can be present such as surfactants and the like. In addition, other biocides, such as formaldehyde releasing biocides, can also be introduced either before the introduction of the products from the reaction, during the introduction of the products from the reaction, or after the introduction of the products from the reaction into the aqueous system. Also, essentially any other ingredient can be introduced at any time as long as these additional components do not interfere w ith the production of the percarboxylic acid and/or percarboxyl anions. Examples of biocides. include, but are not limited to. Barium Metaborate, 2- (Thiocyanomethylthio)benzothiazole, Potassium N-hydroxy-N-methyldithiocarbamate, Poly[oxyethylene(dimethyliminio)ethylene(dimethvliminio)ethylene] dichloride. Potassium dimethyldithiocarbamate. Disodium cyanodithioimidocarbonate, Potassium N-methyldithiocarbamate, Sodium N-methyldithiocarbamate, 2-Hydroxypropyl methanethiolsulfonate, Methylene bis(thiocyanate), 2-Bromo-4'-hydroxyacetophenone. Hexahydro- 1 ,3,5-tris(2-hydroxyethyl-s-triazine, Tetrahydro-3,5-dimethyl-2H- 1 ,3,5-thiadiazine-thion. Oxydiethylene bis(alkyl*dimethylammonium chloride), l-Methyl-3.5,7-triaza-l-azoniatricyclodecane chloride, 1 ,4-Bis(Bromoacetoxy)-2-butene, Alkyl*dimethyl benzyl ammonium chloride (*40% C12, 50% C14, 10% C16), 1,4- Bis(bromoacetoxy)-2-butene, Glutaraldehyde, l-Bromo-3-chloro-5,5-dimethylhydantoin, Mono(N,N- dimethyl*) salt of Endothall, Sodium Bromide. Bronopol, 5-Chloro-2-Mehtyl-4-isothiazolin-3-one, 2- Methyl-4-isothiazolin-3-one, Sodium Dichloro-s-triazinetrione, Alkyl*dimethyl benzyl ammonium chloride (*40% C12, 50% C14, 10% C16), Trichloro-s-triazinetrione. Sodium hypochlorite, Propiconazole, Chlorothalonil, 2-n-octyl-isothiazoliuone, or combinations thereof. These mixtures of biocides (e.g., percarboxylic acid/anion and second biocide) can be synergistically effective when used to treat systems for the control of microorganisms. Preferably, a mixture of 2- (thiocyanomethylthio)benzothiazole and methylene-bis(thiocyanate) is used with the peracetic acid, peracetyl anions, or both. This combination is effective in providing a composition that is rapid in response time and yet provides extended control of microorganisms. The present invention accordingly also provides a composition to control the growth of at least one microorganism comprising a) a mixture of 2-(thiocyanomethylthio)benzothiazole and methylene-bis(thiocyanate) with b) peracetic acid, peracetyl anions, or both where the components are preferably present in a combined amount effective to control the growth of at least one microorganism. The compositions of the present invention preferably provide superior microbicidal activity at low concentrations against a wide range of microorganisms. The present invention also provides a method for controlling the growth of at least one microorganism in or on a material or medium susceptible to attack by the microorganism which comprises the step of adding to the material or medium a composition of the present invention, where the components of the composition are preferably present in synergistically effective amounts to control the growth of the microorganism. The synergistically effective amount varies in accordance with the material or medium to be treated and can, for a particular application, be routinely determined by one skilled in the art in view of the present invention. The present invention also embodies the separate addition of a mixture of 2- (thiocyanomethylthio)benzothiazole and methylene-bis(thiocyanate) with peracetic acid, peracetyl anions, or both to the products, materials, or media described above. According to this embodiment, the components are individually added to the system so that the final amount of the mixture of 2- (thiocyanomethylthio) benzothiazole and methylene-bis(thiocyanate), and the peracetic acid, peracetyl anions, or both present in the system at the time of use is the amount effective to control the growth of at least one microorganism.

The preparation of 2-(thiocyanomethylthio)benzothiazole is described in U.S. Patent Nos. 3,520,976 and 5,073,638 and the preparation of methylene-bis(thiocyanate) (MTC) is described in U.S. Patent No. 3,524,871, and these disclosures are fully incorporated by reference herein. 2- (thiocyanomethylthio)benzothiazole and methylene-bis(thiocyanate) are both commercially available and they are also easily synthesized from commercially available raw materials. MTC is also known as 2-methylene-bis(thiocyanate).

The 2-(thiocyanomethylthio)benzothiazole and methylene-bis(thiocyanate) mixture is sold in varying concentrations under such commercial names as Busan® 1009, MECT, etc. These commercial products are available from Buckman Laboratories International, Inc. and other distributors. Busan ® 1009 is an emulsifiable concentrate of 10% by weight of 2- (thiocyanomethylthio) benzothiazole and 10% by weight of methylene-bis(thiocyanate). The amounts of the active ingredients in the mixture used as a component in this invention can preferably vary from about 1% to about 80%, preferably from about 1% to about 40%, by weight of 2- (thiocyanomethylthio)benzothiazole and from about 1% to about 80%, preferably 1% to about 40%, by weight of methylene-bis(thiocyanate). The most preferred amounts of these ingredients are those found in Busan® 1009.

As described above, components (a) and (b) are used preferably in synergistically effective amounts. The weight ratios of (a) to (b) vary depending on the type of microorganisms, products, materials, or media to which the composition is applied. One skilled in the art can readily determine in view of this disclosure, and without undue experimentation, the appropriate weight ratios for a specific application. The ratio of component (a) to component (b) preferably ranges from about 99: 1 to about 1 :99, more preferably from about 1 :30 to about 30: 1 , and most preferably from about 1 :5 to about 5: 1. In general, an effective fungicidal, bactericidal, and/or algicidal response can be obtained when the synergistic combination is employed in concentrations (based on the media to be treated or emulsion used) ranging from about 0.01 to about 5000 ppm of the mixture 2- (thiocyanomethylthio)benzothiazole and methylene-bis(thiocyanate), preferably from about 0.1 to about 1000 ppm, and most preferably from about 0.1 to about 500 ppm; and from about 0.1 ppm to about 5000 ppm of the peracetic acid, peracetyl anions, or both, preferably from about 0.1 to about 500 ppm. In accordance with the present invention, the composition may be in the form of a solid, dispersion, emulsion, or solution, depending upon the particular application. Further the components of the composition are preferably applied separately to the product, material, or medium. In lieu of peracetic components as described above, percarboxcylic acid, percarboxyl anions, or both can be used with the biocide(s) in the same manner.

For purposes of the present invention, an aqueous source is any source containing water or which is water-based or aqueous-based.

Generally, the production of the products from the reaction will be at a sufficient concentration to control the growth of at least one microorganism. It is understood that by "controlling" the growth of at least one microorganism, the growth of the microorganism is inhibited and/or prevented. In other words, there is no growth or essentially no growth of the microorganism. "Controlling" the growth of at least one microorganism can further include maintaining the microorganism population at a desired level, reducing the population to a desired level (even to undetectable limits, e.g., zero population), and/or inhibits the growth of at least one microorganism. Thus, the products, materials, or media susceptible to attack by these type of microorganisms are preserved from this attack and the resulting spoilage and other detrimental effects caused by the microorganism can be avoided. Further, it is also to be understood that '^•controlling" the growth of at least one microorganism can also include biostatically reducing and/or maintaining a low level of microorganism such that the attack by a microorganism and any resulting spoilage or other detrimental are mitigated, i.e., the microorganism growth rate or microorganism attack rate is slowed down or eliminated.

Examples of microorganisms include, but are not limited to, fungi, bacteria, algae, yeast, spores, and mixtures thereof. The present invention also has the ability to inhibit enzymatic catalase in the same manner that microorganisms can be controlled.

Since the system of the present invention is capable of producing effective amounts of percarboxylic acid and/or percarboxyl anions which are effective in controlling the growth of at least one microorganism, the present invention is also directed to methods for controlling the growth of at least one microorganism by reacting the reactants together to form the percarboxylic acid and/or percarboxyl anions which have the ability to control the growth of at least one microorganism.

Preferably, the amount of the percarboxylic acid and/or percarboxyl anions formed from this reaction can be any amount based on the amount of reactants used and the amount of aqueous solvent present during the reaction, however, it is desirable to have a sufficient amount of aqueous solvent as well as reactants to form a solution which contains from about 1 to about 40% (by weight) percarboxylic acid and/or percarboxyl anions and more preferably about 5% (by weight) percarboxylic acid and/or percarboxyl anions by concentration in the aqueous solution. This solution can then be introduced as discussed above to treat the aqueous system.

The following summary entails biological efficacy date, a preferred formulation, a preferred reaction mechanism, stability of reacting composition, hydroscopicity of formulated material, and observed physical characteristics:

Preferred formulation: Warwick B Series TAED Granulate 15%-20% (by weight), more preferably

17%.

Potassium peroxysulfate (BRD 2350) 40%-70%, more preferably, 67%

Citric Acid (Anhydrous) 15%-40%, more preferably 17%

Preferred Reaction Mechanisms:

TAED + Potassium peroxysulfate yields Peracetic acid + DAED and its salt; or

TAED + Potassium peroxysulfate yields amounts of mono and diacetylethylene diamine and salts thereof.

TAED is supplied as 75% active. K peroxysulfate is supplied as 42.8% active

*Reaction runs to completion. Efficiency of reaction suggests approx. 100% production of available (2) acetals to produce maximum amount of peracid. *The use of other oxidizers such as Sodium carbonate peroxyhydrate or sodium perborate monohydrate produced efficiency of reactions which suggest only 10% and generated gas (C02) and foam.

The present invention will be further clarified by the following examples, which are intended to be purely exemplary of the present invention.

EXAMPLES

Example 1 Biological efficacy data:

A sample of microbial slime was procured from a paper mill. The inclusive microbial species prefer culture conditions typical of a mill : Temperature 40-50 C, pH 6.5 - 8.0, some available soluble starch. Efficacy assays were run at these preferred conditions in synthetic paper mill water to simulate these conditions. Peracetic acid and peroxide residuals were assayed by chemical strips supplied by EM SCIENCE Industries, located in Gibbstown, NJ. Strips were manufactured in Germany.

Data: Temp. 40 C pH ~ 6.5

Peracid Level 10 ppm 50% reduction in microbial population in 1 hour 20 ppm 90 to 98% reduction in microbial population in 1 hour 40 ppm 99% reduction in microbial population in 1 hour 60 ppm 99.8% reduction in microbial population in 1 hour

Data Conditions = Temp. 50 C. pH ~ 6.5, Exposure 1 hour

Peracid Level 20 ppm 95 to 98% reduction in microbial population 40 ppm 99% reduction in microbial population in 60 ppm 99.8% reduction in microbial population 100 ppm 99.9% reduction in microbial population

Date Conditions = Temp. 40 C, pH ~ 7.5 to 7.6, Exposure 1 hour

Peracid Level 10 ppm 85 to 90% reduction in microbial population 20 ppm 98% reduction in microbial population 40 ppm 99% reduction in microbial population 50 ppm 99% reduction in microbial population 100 ppm 99.5% reduction in microbial population

Date: Conditions ^: Temp. 50 C pH ~ 7.5 to 7.6. Exposure 1 Hour Peracid Level 10 ppm 90 to 94% reduction in microbial population 20 ppm 98% reduction in microbial population 40 ppm 98 5% leduction in microbial population 50 ppm 99% reduction in microbial population

100 ppm 99 5% reduction in microbial population Date Conditions ^: Temp 40 C. pH ~ 7 5 to 7 6. Exposure 3 hours

Peracid Level 20 ppm 99 9% reduction in microbial population

50 ppm 99 9% reduction in microbial population

Busan 1009 Level 20 ppm no significant reduction in microbial population 40 ppm 80% reduction in microbial population

Combination

Busan® 1009/Peracιd (PAA) 20 ppm /20 ppm 99 99% reduction in microbial population 20 ppm/50 ppm results suggested approximating extinction of microbial population

Combination

Busan® 1009/Peracιd (PAA) 40 ppm /20 ppm results suggested approximating extinction of microbial population 40 ppm/50 ppm results suggested approximating extinction of microbial population

*The results of combination studies show that s\ nergιstιc activity exists between Busan® 1009 biocide and Peracetic acid Peracetic acid demonstrates an immediate reduction activity within a short period to time, while Busan® 1009 biocide offers an extended efficacy over time

*Accordιng to assay strips, peracetic acids used at initial challenge rates (10 to 100 ppm) appeared to chemically degrade within a few hours Its chemical presence was not detected beyond 5 hours Likewise, peroxide residuals were not detectable within limits of assay after 5 hours

Stability of Reacting Composition Reacting Composition is defined as the composition of formulated materials which would generate 1% 3%, and 5% peracetic acid in a process vessel

00/69778

-17-

Data: Time Day 1 Day 3 Day 5 Day 7

Peracid

1% 75% remained 50% remained 50% remained 50% remained 3% 95% remained 95% remained 90% remained 90% remained

5% 97% remained 95% remained 93% remained 93% remained

Hydroscopicity of formulated composition:

Exposed openly to room atmosphere at 20 C for 1 week. Results indicated that formula absorbed 4.0 to 5.0% moisture.

Observed Physical Characteristics:

1) Formulated composition is substantially not reactive until contact with water;

2) The pH of the hydrated processing vessel ill approach 1.0 as peracid generates; 3) No foam generated in process: and some gas generated in process, most likely oxygen gas;

4) Some salt residue formed in process vessel;

5) Peracid stability in process vessel appears good (>90%);

6) If desired, heat up to 40-50C may be added to process vessel; but it is not required; 7) Peracid at use levels performs rapid biological efficacy;

8) Peracid at use levels chemically degrades within a few hours; and

9) Peracid at use levels suggests synergistic activity with certain other bioactives.

Example 2 In this example, the organism E. cterogenes was introduced into artificial pulp white water having a pH of from about 6.6 to 6.8. The amount of organisms present was 1 X 10⁶ organisms per ml of white water. The temperature of the solution was 25° C and the test was run for approximately 3 hours(contact time). In the test, a 20% solution of (17% by wt. TAED, 17% by wt. citric acid, and 67% by wt. potassium peroxy sulfate made up in a balance of water to produce a 20% solution) was introduced in the amounts indicated in Table 1. The percentage of organism killed is based on a comparison of the control where no peracetic acid solution was present. As can be seen in Table 1, the peracetic acid made by the present invention was quite effective in controlling this organism. -18-

Table 1 *

Concn. Busan 1000 Time Zero

100 ppm 99.999

60 ppm 99.999

40 ppm 99.99

20 ppm 99.99

10 ppm 99.9

5 ppm 99.0 * At Time Zero the bacteria concentration was 1 X 10⁶/ml [Control]

A sporicidal study was then preformed against spores of Bacillus cereus with the same solution described above, wherein the contact time was 24 hours. Table 2 reflects the concentration of the peracetic acid as well as the spore concentration and the percentage of reduction of the spore population. Again, as can be seen, the peracetic acid of the present invention was quite effective in controlling the spore population.

Table 2

Concn. Spores/ml % of Control Reduction 3000 ppm 380,000 92.2 2000 ppm 520,000 89.4 1000 ppm 650,000 86.7

Using the same formulation as above, a bacterial alkaline fine paper slime inoculum containing three species was treated with the peracetic acid of the present invention at various temperatures and pHs as indicated in Table 3. The inoculum was approximately 2-3 X 10 /ml of synthetic alkaline white water. As can be seen in the results in Table 3, the peracetic acid of the present invention was quite effective at various pHs and temperatures with contact times of 1 hour.

Table 3

Concn. Temp. PH Time % of Control Reduction

60 ppm 40 C 6.5 lhr 99.8

40 ppm 40 C 6.5 lhr 99.0

20 ppm 40 C 6.5 lhr 98.0

10 ppm 40 C 6.5 lhr 50.0

100 ppm 50 C 7.5 lhr 99.5

50 ppm 50 C 7.5 lhr 99.0

40 ppm 50 C 7.5 lhr 98.5

20 ppm 50 C 7.5 lhr 98.0

10 ppm 50 C 7.5 lhr 94.0

A similar study was conducted against Pink Slime bacteria from a papermill sample with the same peracetic acid solution. The inoculum was approximately present in an amount of 1 X 10 /ml of papermill solution. Table 4 sets forth the results and further details of the concentration of the peracetic acid, the temperature of the test, pH of the test, and the contact time. Again, the peracetic acid of the present invention was quite effective in reducing the bacteria count.

Table 4

Concn. Temp. pH Time % of Control Reduction

60 ppm 40 C 6.8 3hr 99.9

40 ppm 40 C 6.8 3hr 99.9

25 ppm 40 C 6.8 3hr 99.9

10 ppm 40 C 6.8 3hr 99.9

Finally, in this example, a catalase inhibition study was preformed using Pseudomonas aeruginosa cells. These test samples were incubated at room temperature for 20 minutes in the presence of the peracetic acid of the present invention at the various concentrations set forth in Table 5. As set forth in Table 5, the percent of catalase enzymatic inhibition was recorded and the peracetic acid of the present invention was quite effective in controlling or inhibiting the catalyzed enzyme activity. Table 5

Concn. % of Catalase enzymatic inhibition 1000 ppm 99.6

500 ppm 99.2

250 ppm 99.1

100 ppm 98.9

50 ppm 72.5

From the above, it can be clearly seen that the peracetic acid of the present invention using methods of the present invention is quite effective in controlling a whole host of microorganisms and inhibiting catalase enzymatic activity.

It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the present invention without departing from the spirit or scope of the present invention. Thus, it is extended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. A method to produce peracetic acid, peracetyl anions, or both comprising reacting a sulfate containing reactant with tetraacetylethylenediamine in an aqueous solvent and at a sufficient temperature and in sufficient amounts to produce a product comprising peracetic acid and/or peracetyl anions.

2. The method of claim 1, wherein said sulfate containing reactant is an alkali metal persulfate.

3. The method of claim 1. wherein said sulfate containing reactant is a potassium persulfate, a sodium persulfate, or mixtures thereof.

4. The method of claim 1, further comprising introducing a hydrogen donating species prior to or during the reaction.

5. The method of claim 4, wherein said hydrogen donating species is an acid.

6. The method of claim 4, wherein said hydrogen donating species is an organic acid or a mineral acid.

7. The method of claim 4, wherein said hydrogen donating species is citric acid.

8. The method of claim 1 , wherein said reaction has a conversation rate of from about 70% to about 98% of the tetraacetylethylenediamine to peracetic acid, peracetyl anions, or both.

9. The method of claim 1, wherein said aqueous solvent is water.

10. The method of claim 1, wherein diacetylethylenediamine is produced along with said peracetic acid, peracetyl amines, or both.

1 1. The method of claim 1, wherein about 2 moles of said sulfate containing reactant are combined with about 1 mole of tetraacetylethylenediamine to form about 1 mole of diacetylethylenediamine and about 2 moles of peracetic acid, peracetyl anions, or both.

12. The method of claim 5. wherein said tetraacetylethylenediamine is present in an amount of from about 15 wt. % to about 20 wt. %, said sulfate containing reactant is present in an amount of from about 40 wt % to about 70 wt %: and said acid is present in an amount of from about 15 wt % to about 40 wt %.

13. A method for controlling the growth of at least one microorganism in an aqueous system comprising the step of reacting a sulfate containing reactant with tetraacetylethylenediamine in an aqueous solvent and at a sufficient temperature and in sufficient amounts to produce a product comprising peracetic acid, peracetyl anions, or both and then introducing said product to said aqueous system in an amount effective to control at least one microorganism.

14. The method of claim 13, wherein said microorganism is bacteria, fungi, algae, yeast, spore or mixtures thereof.

15. The method of claim 13, wherein said aqueous system is present in a cooling water tower, a pulp or paper manufacturing system, a brewery, a pasteurization system, or a reverse osmosis system.

16. The method of claim 13, wherein said aqueous system is a swimming pool, hot tub, a pond, a Jacuzzi, water rides, or spray washes.

17. The method of claim 13, wherein said concentration of the peracetic acid, peracetyl anions or both, is from 1 to about 40% by weight in said aqueous system.

18. The method of claim 13, wherein said reaction occurs at ambient temperatures.

19. The method of claim 13, further comprising introducing at least one biocide to the aqueous system.

20. The method of claim 19, wherein said biocide is 2-thiocyanomethylthio(benzothiazole), methylene-bis(thiocyanate) or a mixture thereof.

21. A method to control the growth of at least one microorganism in an aqueous system comprising reacting a sulfate containing reactant with tetraacetylethylenediamine in said aqueous system and at a sufficient temperature and in sufficient amounts to produce a product comprising peracetic acid, peracetyl anions, or both in said aqueous system.

22. A method to produce percarboxylic acid, percarboxyl anions, or both comprising reacting a sulfate containing reactant with at least one acid generating acyl activator in an aqueous solvent and at a sufficient temperature and in sufficient amounts to produce a product comprising percarboxylic acid, percarboxyl anions. or both.

23. The method of clam 22, wherein said acid generating acyl activator is acetylsalicylic acid, diacetyl dioxohexahydrotriazine, tetracetyl glycoluril. tetracetyl methylmethylene diamine, pentacetylglucose, tetraacetylethylenediamine (TAED) or mixtures thereof.

24. A method for controlling the growth of at least one microorganism in an aqueous system comprising the step of reacting a sulfate containing reactant with at least one acid generating acyl activator in an aqueous solvent and at a sufficient temperature and in sufficient amounts to produce products comprising percarboxylic acid, percarboxyl anions. or both and then introducing said product to said aqueous system in an amount effective to control at least one microorganism.

25. A method to control the growth of at least one microorganism in an aqueous system comprising reacting a sulfate containing reactant with at least one acid generating acyl activator in said aqueous system and at a sufficient temperate and in sufficient amounts to produce a product comprising percarboxylic acid, percarboxyl anions, or both in said aqueous system.

26. A composition to control the growth of at least one microorganism comprising a microbicidally effective mixture of (a) a mixture of 2-thiocyanomethylthio(benzothiazole) and methylene-bis(thiocyanate), and

(b) peracetic acid, peracetyl anions, or both.

27. The composition of claim 26, wherein the microorganism is selected from bacteria, fungi, algae, or mixtures thereof.

28. The composition of claim 26, wherein the weight ratio of (a) to (b) is from about 99: 1 to about 1:99.

29. The composition of claim 28. wherein the weight ratio of (a) to (b) is from about 1 :30 to about 30: 1.

30. The composition of claim 29, wherein the weight ratio of (a) to (b) is from about 1 :5 to about 5:1.

31. The composition of claim 26, wherein the weight ratio of concentrations are from about 0.01 to about 5000 ppm of the mixture of 2-thiocyanomethylthio(benzothiazole) and methylene- bis(thiocyanate), and from about 0.1 to about 5000 ppm by weight of the peracetic acid, peracetyl anions, or both.

32. The composition of claim 31, wherein the weight ratio of concentrations are from about 0.1 to about 1000 ppm of the mixture of 2-thiocyanomethyIthio(benzothiazoIe) and methylene- bis(thiocyanate), and from about 0.1 to about 2000 ppm of the peracetic acid, peracetyl anions, or both.

33. The composition of claim 32, wherein the weight ratio of concentrations are from about 0.1 to about 500 ppm of the mixture of 2-(thiocyanomethylthio)benzothiazole and methylene- bis(thiocyanate), and from about 0.1 to about 500 ppm of the peracetic acid, peracetyl anions, or both.

34. A method of controlling the growth of at least one microorganism in or on a product, material, or medium susceptible to attack by said microorganism comprising the step of applying to said product, material, or medium, a composition to control said growth comprising a microbicidally effective mixture of

(a) a mixture of 2-(thiocyanomethylthio)benzothiazole and methylene-bis(thiocyanate), and

(b) peracetic acid, peracetyl anions, or both.

35. A composition to control the growth of at least one microorganism comprising a microbicidally effective mixture of

(a) a mixture of 2-thiocyanomethylthio(benzothiazole) and methylene- bis(thiocyanate), and

(b) percarboxylic acid, percarboxyl anions, or both.