Antibacterial system and method for treating industrial process water

Abstract

(a) Antibacterial Compounds According to Formula I [Formula 1] TIFF2025501108000010.tif52170 and (b) an antimicrobial system comprising a stabilized chlorine compound, said compounds being separate compounds or constituting a single composition, In the formula, R1, R2, and R3 independently represent a hydrogen atom; a halogen atom; a hydroxy group; an amino group; an alkylamino group, an alkyl group, a hydroxyalkyl group, an acyl group, a haloalkyl group, or an alkoxy group having 1 to 4 carbon atoms; or an acylamide group having 1 to 10 carbon atoms, A represents 2-thiazolamine; 2-propenenitrile; 2-propenoic acid; an alkyl or hydroxyalkyl ester of 2-propenoic acid having 1 to 4 carbon atoms; or a -CHCHCONR5R6 group, where R5 and R6 independently represent a hydrogen atom, an alkyl or hydroxyalkyl having 1 to 4 carbon atoms; The system, wherein the stabilized chlorine compound comprises a reaction product of a reaction between active chlorine and a nitrogen-based reactant selected from ammonium, urea, carbamate, and dimethylhydantoin.

Description

[Technical field]

[0001] The present invention relates to methods for treating industrial process water, methods for reducing or preventing the growth of microorganisms, such as bacteria, and systems and compositions therefor. [Background technology]

[0002] Microorganisms such as bacteria can cause problems, for example, when equipment or machinery used in industrial processes comes into contact with water systems. Bacteria in water can exist in a free-floating form (sometimes known as planktonic) or can be in the form of a surface-associated biofilm. Biofilms, in particular, can be difficult to remove because they include not only the bacterial mass but also a protective sheath or film formed by the bacteria.

[0003] High levels of bacterial growth can be extremely problematic in industrial processes. For example, industrial process waters used in the manufacture of pulp, paper, and paperboard are particularly susceptible to bacterial growth problems. These processes use water that contains microbial nutrients such as cellulose fibers and starch, and are operated at temperatures that allow microorganisms to thrive. It is also common in manufacturing processes to recirculate the same process water several times. If left untreated, paper and paperboard products can become defective and require regular downtime periods for cleaning. It is therefore desirable to manage the microbial problem, which has been achieved by adding biocidal substances to the process water.

[0004] Halogenated compounds have been shown to be effective biocides. Haloamines and chlorine dioxide are effective chemicals for microbial control due to their ability to oxidize components of bacterial cells. Haloamines and chlorine dioxide are relatively inexpensive and, at high enough concentrations, can minimize both planktonic bacteria levels and prevent biofilm slime formation on system surfaces.

[0005] Although these biocides are effective, the presence of active halogens, such as active chlorine, has been found to cause corrosion problems on metal surfaces. In the paper industry, these problems occur primarily at the gas phase or at the interface between the water and gas phase. One solution to this problem is presented in US Pat. No. 5,399,633, in which halogenated hydantoins were used in combination with haloamines. However, halogenated hydantoins are expensive and contain active halogens themselves, which may still contribute somewhat to corrosion problems.

[0006] Thus, there remains a need to provide effective control of microorganisms in industrial circulating water systems used, for example, in the manufacture of paper and paperboard, while at the same time minimizing corrosion problems. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] European Patent No. 2297046 Summary of the Invention

[0008] In a first aspect, the present invention provides: (a) an antibacterial compound according to formula I

[0009] [ka]

[0010] and (b) providing an antimicrobial system comprising a stabilized chlorine compound; The compounds may be separate compounds or may comprise a single composition, In the formula, R1, R2, and R3 independently represent a hydrogen atom; a halogen atom; a hydroxy group; an amino group; an alkylamino group, an alkyl group, a hydroxyalkyl group, an acyl group, a haloalkyl group, or an alkoxy group having 1 to 4 carbon atoms; or an acylamide group having 1 to 10 carbon atoms. A represents 2-thiazolamine; 2-propenenitrile; 2-propenoic acid; an alkyl or hydroxyalkyl ester of 2-propenoic acid having 1 to 4 carbon atoms; or a -CHCHCONR5R6 group, where R5 and R6 independently represent a hydrogen atom, an alkyl or hydroxyalkyl having 1 to 4 carbon atoms; The stabilized chlorine compound comprises the reaction product of a reaction between active chlorine and a nitrogen-based reactant selected from ammonium, urea, carbamate, and dimethylhydantoin. The antimicrobial compound and the stabilized chlorine compound may be used separately, sequentially, or simultaneously.

[0011] In a second aspect, the present invention provides a method for treating industrial process water, the method comprising: (i) administering to a patient an amount of an antimicrobial compound according to formula I;

[0012] [ka]

[0013] and (ii) administering to said industrial process water an amount of a stabilized chlorine compound; In the formula, R1, R2, and R3 independently represent a hydrogen atom; a halogen atom; a hydroxy group; an amino group; an alkylamino group, an alkyl group, a hydroxyalkyl group, an acyl group, a haloalkyl group, or an alkoxy group having 1 to 4 carbon atoms; or an acylamide group having 1 to 10 carbon atoms. A represents 2-thiazolamine; 2-propenenitrile; 2-propenoic acid; an alkyl or hydroxyalkyl ester of 2-propenoic acid having 1 to 4 carbon atoms; or a -CHCHCONR5R6 group, where R5 and R6 independently represent a hydrogen atom, an alkyl or hydroxyalkyl having 1 to 4 carbon atoms; The stabilized chlorine compound comprises the reaction product of a reaction between active chlorine and a nitrogen-based reactant selected from ammonium, urea, carbamate, and dimethylhydantoin. The antimicrobial compound and the stabilized chlorine compound may be administered separately, sequentially, or simultaneously. The compounds may be administered to the industrial process water at the same location or at different locations within the same industrial process.

[0014] The method of treating industrial process water may reduce or prevent the growth of microorganisms, such as bacteria. Such growth may be of free planktonic microorganisms or of microorganisms present in structures, such as biofilms. This may occur by killing existing microorganisms or by halting the growth of new microorganisms. In this way, the formation of biofilms may also be reduced or prevented, and existing formed biofilms may be reduced or removed, for example, by dissolution of the biofilm such that the microorganisms become planktonic and are subsequently killed.

[0015] Surprisingly, it has been found that the combination of antibacterial compound and stabilized chlorine compound according to the present invention can effectively act against biofilms even when only small amounts of stabilized chlorine compound are used at the same time. This means that when used in industrial equipment or facilities, the antibacterial system requires less active chlorine, which reduces corrosion. The production of less active chlorine also results in a safer working environment, and inexpensive stabilized chlorine compounds can be used effectively.

[0016] Without wishing to be bound by theory, it is believed that the presence of antimicrobial compounds prevents biofilm formation and promotes biofilm dissolution. Stabilized chlorine compounds are particularly effective against planktonic microorganisms, even at low concentrations of the compounds. The high concentrations of stabilized chlorine compounds previously required to be effective against biofilms are not necessary in the presence of antimicrobial compounds.

[0017] The antibacterial compounds have structural formula I, where R1, R2, and R3 are independently substituents at the ortho, meta, and para positions of the benzene ring.

[0018] Advantageously, R1 represents a methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy or tert-butoxy group, and / or R2 and R3 independently represent a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a methoxy group, an ethoxy group, a propoxy group, a isopropoxy group, a n-butoxy group, a tert-butoxy group, and / or A represents 2-propenenitrile.

[0019] Alternatively, R1 represents a methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, tert-butoxy, or amino group; and / or R2 and R3 each independently represent a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a methoxy group, an ethoxy group, a propoxy group, a isopropoxy group, a n-butoxy group, or a tert-butoxy group; and / or A represents a -CHCHCONR5R6 group, where R5 and R6 independently represent a hydrogen atom, an alkyl or a hydroxyalkyl having 1 to 4 carbon atoms, and preferably R5 and R6 represent a hydrogen atom.

[0020] Preferably, the compound according to formula I is selected from the group consisting of 3-[(4-methylphenyl)sulfonyl]-2-propenenitrile, 3-phenylsulfonyl-2-propenenitrile, 3-[(4-fluorophenyl)sulfonyl]-2-propenenitrile, 3-[(4-trifluoromethylphenyl)sulfonyl]-2-propenenitrile, 3-[(2,4-dimethylphenyl)sulfonyl]-2-propenenitrile, 3-[(3,4-dimethylphenyl)sulfonyl]-2-propenenitrile, 3-(3,5-dimethylphenyl)sulfonyl-2-propenenitrile, 3-[(2,4,6-trimethylphenyl)sulfonyl]-2-propenenitrile, 3-(4-methoxyphenyl)sulfonyl-2-propenenitrile, 3-[(4-methylphenyl)sulfonyl]prop-2-enamide, 3-[(4-methylphenyl)sulfonyl]prop-2-enoic acid, and any isomers thereof. Of these compounds, it is more preferred that the compound according to formula I is selected from the group consisting of 3-[(4-methylphenyl)sulfonyl]-2-propenenitrile, 3-phenylsulfonyl-2-propenenitrile, 3-[(4-trifluoromethylphenyl)sulfonyl]-2-propenenitrile, 3-[(2,4,6-trimethylphenyl)sulfonyl]-2-propenenitrile, 3-(4-methoxyphenyl)sulfonyl-2-propenenitrile, and 3-[(4-methylphenyl)sulfonyl]prop-2-enamide, and any isomers thereof. It is especially preferred that the compound is 3-[(4-methylphenyl)sulfonyl]-2-propenenitrile.

[0021] Antibacterial compounds suitable for use in the present invention and their synthesis are also described in WO 2019 / 042984 and WO 2019 / 042985.

[0022] The stabilized chlorine compounds include the reaction products of the reaction between active chlorine and a nitrogen-based reactant selected from ammonium, urea, and dimethylhydantoin. The reaction is well known and is typically carried out in situ so that the stabilized chlorine compounds are freshly prepared for use. This is because stabilized chlorine solutions have limited storage stability.

[0023] Ammonium is typically provided in salt form and is the preferred nitrogen-based reactant. Preferred ammonium salts are ammonium sulfate, ammonium bromide, ammonium carbamate, and ammonium chloride. Chlorine is typically provided in the form of an active chlorine source, such as a hypochlorite salt. A preferred active chlorine source is sodium hypochlorite.

[0024] The reaction is usually carried out by simply mixing the reactants in the presence of dilution water. In the case of ammonium and urea, mixing with chlorine at too high a concentration can degrade the stabilized chlorine compounds in the solution. It is therefore preferred to dilute the reactants so that the stabilized chlorine compound product formed has an active chlorine concentration of 500 to 10,000 mg / l. The molar ratio of active chlorine to nitrogen is preferably approximately 1:1, since the closer to an equimolar ratio the more stable the stabilized chlorine solution. It is also preferred that the mixing is carried out under alkaline conditions. For example, mixing ammonium with hypochlorite leads to the formation of monochloramine (MCA). Dilution with water at a molar ratio (active chlorine to nitrogen) of 1:1 to a final concentration of active chlorine of 5,000 mg / l at pH 9.0 results in a stabilized chlorine solution in which monochloramine is stable for more than one hour. However, mixing at a higher ratio of active chlorine to nitrogen and below pH 7 can result in, for example, the formation of undesired dichloramine and can also affect the stability of the stabilized chlorine solution.

[0025] Stabilized chlorine compounds made from dimethylhydantoin usually require reaction with sodium hypochlorite (see U.S. Pat. No. 6,429,181). In this way, monochloro-5,5-dimethylhydantoin (MCDMH) can be formed. This reaction is also carried out by mixing. However, dilution water is not necessary. For example, it is possible to directly mix 15% hypochlorite and 15% dimethylhydantoin (in water). The mixing ratio is also not critical. If active chlorine is provided in excess, the amount of monochloro-5,5-dimethylhydantoin is simply limited by the amount of dimethylhydantoin available. Excess active chlorine simply remains as free active chlorine without stabilization. Dimethylhydantoin is the least preferred nitrogen-based reactant because it is relatively expensive.

[0026] A particularly useful combination of antimicrobial compound and stabilized chlorine compound is 3-[(4-methylphenyl)sulfonyl]-2-propenenitrile and MCA (monochloramine).

[0027] The method of the present invention is applicable to various industrial processes. Many of these processes use process waters that contain components that provide nutrients to microorganisms. In addition, many industrial processes operate at high temperatures, such as at least 40° C. or at least 50° C., which can also promote microbial growth. Microorganisms present in the process water can grow in biofilms and cause biofouling and biocorrosion, also known as microbiologically influenced corrosion (MIC). Microbial biofilms can reduce conductive heat transfer on surfaces and clog hydraulic systems, resulting in energy losses and production cutbacks and shutdowns.

[0028] Typical bacteria found in industrial process waters include Meiothermus, Deinococcus, and / or Pseudoxanthomonas. MICs can also be caused by, for example, Sulphate-reducing bacteria (SRB), Sulphate-reducing Archae (SRA), Acidogenic bacteria, Methanogens, or Iron-oxidizing bacteria. Proteobacteria are the major microbial group found in cooling water biofilms.

[0029] The industrial process waters to be treated relate to water from any equipment or facility used in any industry, including industrial circulating waters. These include waters used in industrial manufacturing processes, waters used as cooling waters that may be circulated through piping, and waters used in the oil and gas industry. Examples of waters in the oil and gas industry that require microbial inhibition include injection waters, fracturing fluids, tank storage, pipelines, and hydrostatic test waters.

[0030] Alternatively, or in addition, the antimicrobial system of the present invention may be added to a cooling water system, which may be in a separate circuit from the industrial manufacturing process. Typically, such cooling water systems include circulating water in contact with a heat exchanger that contacts process water or equipment from the industrial manufacturing process. Cooling water systems may operate at a wide range of temperatures, depending on the temperature of the water supply as well as the temperature to which the industrial process or equipment is being cooled. Temperatures ranging from 5°C to 50°C or higher are found. Many such systems operate at higher temperatures, such as at least 30°C.

[0031] Industrial manufacturing processes involving fibrous materials, such as the production of paper, paperboard, pulp, tissue, moulded pulp, nonwovens, viscose, etc., are particularly suitable for the treatment according to the invention. The industrial process water preferably comprises at least water, naturally occurring cellulosic fibrous material, fines and / or fibre fragments. The process water may also comprise starch. The cellulosic fibrous material is usually derived from softwood, hardwood or non-wood sources, such as bamboo, straw or kenaf, or any mixture thereof. Preferably, the cellulosic fibrous material is derived from lignocellulosic fibrous material. More preferably, the cellulosic fibrous material is a lignocellulosic fibre. The cellulosic fibrous material may be derived from any suitable mechanical, chemimechanical or chemical pulping process, or any combination thereof, or any other suitable pulping process known per se. The cellulosic fibrous material may also comprise fibrous material derived from recycled paperboard, paper or pulp. For example, the cellulosic fibrous material may include cellulosic fibers derived from hardwood and having a length of 0.5-1.5 mm, and / or derived from softwood and having a length of 2.5-7.5 mm. The process water may also include inorganic mineral particles, such as fillers and / or coating minerals; hemicellulose; lignin; and / or dissolved and colloidal substances. The process water may also include papermaking additives, such as starch, sizing agents, inorganic or organic flocculating or agglomerating agents, natural or synthetic polymers of various lengths and / or charges, dyes, optical brighteners, or any combination thereof.

[0032] In one configuration, the industrial manufacturing process has process water containing naturally occurring cellulosic fibrous material and is a pulp and / or paper and / or paperboard manufacturing process, where the process water exhibits high temperatures and / or high flow rates. Thus, the antimicrobial system of the present invention is added or administered to the pulp and / or paper and / or paperboard manufacturing system. The process water in these processes often exhibits high flow rates and high shear rates, which may induce biofilm formation on process surfaces due to microbial stress. For example, in paper and paperboard making environments, the flow rates are typically higher than 1 m / s, even above 10 m / s, and may typically be between 1-20 m / s or 1-10 m / s. The antimicrobial system of the present invention has been observed to be particularly effective in these demanding conditions and may be used generally throughout the entire process to reduce or prevent microbial growth and biofilm formation on process surfaces.

[0033] The industrial manufacturing process involving naturally occurring cellulosic fibre material may be a pulp and / or paper and / or paperboard manufacturing process, the aqueous environment of which has a pH in the range of 5 to 9, preferably 7 to 8.5.

[0034] In one configuration of the invention, the antimicrobial system of the invention may be added in an industrial manufacturing process having process water containing cellulosic fibrous material, which is a paper and / or paperboard manufacturing process, in particular in the short loop of the paper or paperboard making process. In a typical paper and paperboard making process, the pulp stock enters the headbox, which distributes the pulp stock onto a moving wire in the forming section, on which a continuous paper web is formed. Here, the short loop or short circulation section of the paper / board machine is understood as the part of the manufacturing system that recycles and reuses at least a portion of the excess water from the pulp stock, which is collected in the wire pit of the forming section and returned to the headbox for reuse, as is customary in the art.

[0035] Alternatively, or in addition, the antimicrobial system of the present invention may be added to process water in industrial manufacturing processes having process water containing cellulosic fibrous material, such as pulp and / or paper and / or paperboard manufacturing processes, anywhere in the process, including, for example, circulating water tanks, circulating water towers, filtered water towers; clear or cloudy filtrate storage tanks; pulpers; water streams upstream / downstream of the pulper; process water streams upstream / downstream of the broken paper system and vessels therein; pit process streams upstream / downstream of the wire pit; chest process streams upstream / downstream of the paper machine blend chest; fresh water tanks; hot water tanks and / or shower water tanks.

[0036] Alternatively or additionally, the antimicrobial system of the present invention may be added anywhere in the long loop of the paper or board making process in an industrial manufacturing process having process water containing cellulosic fibrous material, which is a paper and / or board making process. Here, the long loop or long circulation section of the paper / board machine is understood as the part of the manufacturing system that handles excess water and broke, as is customary in the art. Most of the recovered water leaves the short loop and is injected into the long loop. This includes a save-all to capture useful fiber from the recovered water for reuse; a storage tank for filtered water used in machine showers, etc.; and a storage tank for recirculated water used as dilution water, etc. for taking pulp from the pulp mill to the paper / board machine. Part of the long loop is the broke system for handling wet and dry paper rejects from the machines. This material is repulped and reused as part of the pulp stock.

[0037] The antimicrobial compound and the stabilized chlorine compound may be added to the process water as a solid, such as a dry powder, or more preferably in liquid form. The compounds may be administered continuously or periodically. According to one configuration, one or both compounds may be administered periodically to the process water for 3-45 minutes 6-24 times per day, preferably 10-30 minutes 12-24 times per day.

[0038] The antimicrobial compound and the stabilized chlorine compound may be added as a single composition, but more typically, they are added separately or sequentially. They may be added simultaneously, either as a single composition or as separate components at the same time. Alternatively, they may be added sequentially as separate components. Addition as separate components may be at the same location or at different locations in the process water. Regardless of how the components are added, both need to be dosed to the process water to realize the combined effect.

[0039] The antimicrobial compound may be administered to the process batchwise or continuously. Preferably, the compound is administered continuously at one to three administration points in the process in such a manner that it reaches all parts of the process prone to biofilm formation. These parts include the blend chest, short loop, head box, wire pit, circulating water tank or tower, save-all, filtered water tank or tower, fresh water tank, hot water tank, and / or shower water tank, preferably the short loop, circulating water tank or tower, filtered water tank or tower, and / or shower water tank.

[0040] Stabilized chlorine may be dosed to the process batchwise or continuously. Preferably, it is dosed at several dosing points in the system, especially in locations less susceptible to corrosion, preferably avoiding short loops and headboxes. These locations include pulpers, pulp tanks or towers, blend chests, machine chests, circulating water tanks or towers, filtered water tanks or towers, fresh water tanks, hot water tanks, and / or shower water tanks, save-alls, recovered fiber tanks, broke pulpers, wet broke tanks or towers, and / or dry broke tanks or towers, preferably blend chests, machine chests, circulating water tanks or towers, filtered water tanks or towers, broke pulpers, wet broke tanks or towers, and / or dry broke tanks or towers.

[0041] Both compounds may be added to the process batchwise, both compounds may be added to the process continuously, or one compound may be added batchwise and the other continuously.

[0042] In principle, the compounds may be added at almost any point in the process, particularly to recirculating process water, to maintain suppression of microbial and / or biofilm formation throughout the process. Additionally or alternatively, the compounds may be added to a feed stream. For example, one or both compounds may be added to cellulosic fibrous material, e.g., lignocellulosic fibrous material, that is used as a feedstock for the process.

[0043] Corrosion is a concern in these industrial environments, for example in paper machines where many steel grades are susceptible to active chlorine or other halogens at the gas phase or the interface between the water and gas phases. Halogen-promoted electrochemical processes can also contribute to corrosion at the interface. Many components of the paper machine above the water level are made of softer steel materials. Such corrosion is especially problematic in short loops. According to the present invention, these problems are minimized because the amount of stabilized chlorine compound administered can be kept to a minimum thanks to the presence of the antimicrobial compound.

[0044] The stabilized chlorine compound may be dosed in an amount ranging from 0.1 to 5 ppm, preferably 0.1 to 2 ppm, more preferably 0.1 to 1 ppm, calculated as active chlorine and based on the volume of the process water. Typically, the amount dosed to the process water may be calculated based on the volume of the process water in the system and, in the case of continuous dosing, the flow rate of the stabilized chlorine compound to the process water. The calculated amount should correspond to the amount measured in the process water if the water supply is clean. If the process water supply contains materials such as organic or chemical compounds in an amount that initially consumes the active chlorine from the stabilized chlorine compound, the calculated amount will not correspond to the amount measured in the process water. In this case, a larger amount of stabilized chlorine compound needs to be used to achieve the amount calculated above as active chlorine, based on the volume of the process water.

[0045] The amount of antimicrobial compound administered is calculated as active compound and based on the volume of the process water, in the range of 0.01-100 ppm, 0.01-50 ppm, 0.01-40 ppm, or 0.01-20 ppm, preferably 0.01-10 ppm, more preferably 0.01-2 ppm. Preferably, the amount of antimicrobial compound administered is calculated as active compound and based on the volume of the process water, in the range of 0.01-1 ppm, preferably 0.01-0.5 ppm, more preferably 0.01-0.3 ppm, even more preferably 0.05-0.2 ppm.

[0046] In general, the antimicrobial system of the present invention may be added to the process water in a biostatic or biocidal amount. A biostatic amount refers to an amount sufficient to at least prevent or inhibit the activity and / or proliferation / growth of microorganisms or biofilms. A biocidal amount refers to a more effective action, such as an amount capable of reducing the activity and / or proliferation / growth of microorganisms or biofilms or killing most or all of the microorganisms present in the process water.

[0047] The present invention further provides the use of an antimicrobial system as defined above for treating industrial process water, such as industrial circulating water.

[0048] The present invention further provides the use of an antimicrobial system as defined above to reduce or prevent the growth of microorganisms in industrial process water.

[0049] The present invention further provides the use of an antimicrobial system as defined above to reduce or prevent the formation of a biofilm and / or to reduce or eliminate an established biofilm.

[0050] The present invention further provides a method for reducing or preventing the growth of microorganisms, preferably bacteria, in industrial process water.

[0051] The present invention further provides methods for reducing or preventing the formation of biofilms and / or reducing or eliminating formed biofilms in industrial process waters.

[0052] The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0053] [Figure 1] 1 is a bar graph showing the corrosive effect of chemical compounds used in the present invention. [Diagram 2] 1 is a further bar graph showing the corrosive effect of chemical compounds used in the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] The term "comprise" as used throughout this specification and claims means "include or consist of." This term means that at least the features that follow this term are included, and does not exclude the inclusion of other features not expressly recited. This term can also mean an entity that consists only of the features that follow this term.

[0055] Experimental procedure Materials and Methods Pure cultures of Meiothermus silvanus, a microbial species commonly found in paper machine biofilms (Ekman J, Journal of Industrial Microbiology & Biotechnology 34, pp. 203-211), and Pseudoxanthomonas taiwanensis, another species commonly found in the paper machine environment (Desjardins, E & Beaulieu, C, Journal of Industrial Microbiology & Biotechnology 30, pp. 141-145), were used to investigate the effectiveness of various chemicals to prevent biofilm formation.

[0056] Biofilm tests were performed in fiber-containing synthetic paper machine water (SPW) (prepared by Peltola, et al., J. Ind. Microbiol. Biotechnol. 38, 1719-1727) using wells of a 96-microwell plate with a peg lid (Thermo Fischer Scientific Inc., USA). Plates were incubated at 45°C with rotary shaking (150 rpm) providing high flow through each well.

[0057] 3-[(4-Methylphenyl)sulfonyl]-2-propenenitrile (hereafter referred to as compound A), from Kemira, purity >98% E isomer.

[0058] 2,2-Dibromo-3-nitrilopropionamide (hereafter referred to as DBNPA) was obtained from Kemira Oyj (Fennosan R20, 20% active ingredient).

[0059] Sodium hypochlorite solution was obtained from Kemira Oyj (15% active ingredient). Since active chlorine decomposes over time, the amount of active chlorine in the solution was measured before each experiment.

[0060] Monochloramine (MCA) was freshly prepared by first adding dilution water to a bottle, then adding a sodium hypochlorite solution containing a known amount of active chlorine. After mixing, an equimolar amount of dilute ammonium sulfate solution was added to give an MCA solution containing 1.0% active chlorine in water.

[0061] Biofilm Test Wells of a 96-microwell plate with a peg lid were filled with SPW and inoculated with pure bacterial cultures. Biofilms were grown for 24 h at 45° C. with rotary shaking (150 rpm) without the addition of any of the chemical compounds being tested.

[0062] 24 hours after the start of the test, the wells were emptied and a fresh solution of SPW was inoculated with pure bacterial cultures along with different amounts of the chemical compounds being tested, and the original peg lids were replaced in their original position. After a further 24 hours, the wells were emptied and the amount of biofilm on the pegs was quantified.

[0063] Quantification of formed biofilm The amount of biofilm formed on the peg surface was quantified with a staining solution by adding 200 μl of a 1% solution of crystal violet (Merck Millipore KGaA, Germany) in methanol to each well of a clean 96-well plate and placing the peg lid containing the biofilm on top. After 3 min, the wells were emptied and the wells and pegs were rinsed three times with tap water. Finally, the peg lid was placed in a clean 96-well plate, the attached crystal violet was dissolved in ethanol, and the absorbance at 595 nm was measured.

[0064] All parts per million (ppm) amounts shown in Examples 1-2 are as active ingredient. Impact values ​​are calculated as a percentage reduction in biofilm based on comparison with no chemical addition. Positive values ​​indicate a reduction in the amount of biofilm, while negative values ​​indicate an increase in the amount of biofilm.

[0065] Table 1 shows the effect of sodium hypochlorite dosing on Meiothermus silvanus biofilms in SPW at 45 °C and 150 rpm (high mixing) in the presence and absence of compound A. Biofilms were stained and quantified by absorbance measurements. Doses are shown as active ingredient.

[0066] [Table 1]

[0067] Table 2 shows the effect of sodium hypochlorite dosing on Pseudoxanthomonas taiwanensis biofilms in SPW at 45°C and 150 rpm (high mixing) in the presence and absence of compound A. Biofilms were stained and quantified by absorbance measurements. Doses are shown as active ingredient.

[0068] [Table 2]

[0069] Tables 1 and 2 demonstrate the ability of the chlorine-containing biocide sodium hypochlorite to reduce and prevent the formation of Meiothermus silvanus and Pseudoxanthomonas taiwanensis biofilms, respectively, in the presence and absence of Compound A. Test conditions mimicked paper or board making process conditions (synthetic paper machine water, high temperature, fiber, high flow). The chlorine-containing biocide sodium hypochlorite was not effective by itself to reach acceptable biofilm reduction effectiveness, even at dosages up to 8 or 16 ppm. To reach acceptable or significant biofilm reduction effectiveness, sodium hypochlorite required dosages of 4 or 8 ppm of active compound in the presence of Compound A.

[0070] Example 2 Table 3 shows the effect of MCA dosing on Meiothermus silvanus biofilms in SPW at 45 °C and 150 rpm (high mixing) in the presence and absence of compound A. Biofilms were stained and quantified by absorbance measurements. Doses are shown as active ingredient.

[0071] [Table 3]

[0072] Table 4 shows the effect of dosing with MCA on Pseudoxanthomonas taiwanensis biofilms in SPW at 45°C and 150 rpm (high mixing) in the presence and absence of compound A. Biofilms were stained and quantified by absorbance measurements. Doses are shown as active ingredient.

[0073] [Table 4]

[0074] Tables 3 and 4 demonstrate the ability of the stabilized chlorine compound MCA to reduce and prevent the formation of Meiothermus silvanus and Pseudoxanthomonas taiwanensis biofilms, respectively, in the presence and absence of compound A. Test conditions mimicked paper or board making process conditions (synthetic paper machine water, high temperature, fiber, high flow). The stabilized chlorine compound MCA was not effective by itself at low dosages to reach acceptable biofilm reduction efficacy. Similarly, compound A was not effective by itself at low dosages to reach acceptable biofilm reduction efficacy. However, in the presence of compound A, MCA required only a dosage of 0.5 or 1 ppm of active compound to reach significant biofilm reduction efficacy. This result indicates that the combination of compound A and MCA can be used at low dosages for effective anti-biofilm efficacy.

[0075] The results regarding anti-biofilm efficacy are surprising and important. At relatively low concentrations, compounds such as sodium hypochlorite are ineffective against biofilms. The presence of the benzenesulfonyl compound, compound A, increases the effect of this biocide compound, but not enough to be highly effective in SPW. If higher concentrations of hypochlorite are contemplated, the presence of even higher levels of active halogens is expected to have a high corrosive effect on industrial equipment. At low concentrations, compound A is also ineffective as an anti-biofilm agent. However, surprisingly, the combination of low concentrations of compound A and low concentrations of MCA was effective against biofilms. This is important for the inhibition of biofilms in industrial processes because it requires the use of only small amounts of active chlorine, significantly reducing the level of corrosion mediated by active chlorine. Similar effects can be obtained from stabilized chlorine compounds other than MCA and benzenesulfonyl compounds of formula (I) other than compound A.

[0076] Example 3 (Corrosion test) In this example, antimicrobial compounds and stabilized chlorine compounds are subjected to corrosion testing.

[0077] The corrosion tests were carried out according to ASTM G31-72. A glass reactor with a volume of 2 L and equipped with a reflux condenser was used under atmospheric pressure. The reactors were immersed in a water bath at a temperature of 55° C. 1.5 L of white water from an alkaline fine paper machine was added to each reactor. The tests were carried out in duplicate in the reactors without stirring and over a period of 7 days. The tests were carried out with a reference sample containing only compound A, MCA and white water. Two stainless steel grades were used in the tests: AISI 304 and AISI 316L.

[0078] Prior to testing, coupons of the appropriate steel grade were polished to remove the passive film from the metal surface. After polishing, the coupon surface was cleaned with ethanol in an ultrasonic bath for 10 minutes and finally degreased and dried with acetone. The coupons were weighed and used on the same day.

[0079] After testing was completed, the coupons were cleaned using a brush, cleaning detergent and hot water, then rinsed with deionized water and pickled in a 5% HCl ultrasonic bath for 10 minutes.

[0080] According to the above test method, corrosion is calculated as uniform corrosion mass loss.

[0081] For each chemical tested, three test coupons were placed in each reactor; one fully immersed in the liquid phase, one half immersed in the liquid phase, and one in the vapor phase. The chemicals tested were dosed into the water to give a final concentration of 0.08 ppm Compound A and 4 ppm MCA as total active chlorine. Chemicals were added at the start and re-dosed once or twice per day during the test. In total, Compound A was dosed six times and MCA was dosed nine times. The dose goal was to match realistic use conditions, i.e., shock doses that would result in fluctuations in the levels of the chemicals in the process water.

[0082] result For the high quality steel 316L grade, no corrosion was observed in any of the samples over the seven day test period.

[0083] For the 304 grade, mild corrosion was observed in only one treatment. In the reactor treated with MCA, semi-immersed coupons showed mild corrosion. However, there was no corrosion in any of the reactors treated with Compound A, nor in the untreated reference. These results are summarized in the bar graph in Figure 1, which shows the average of results from duplicate reactors run at 55°C for 7 days.

[0084] Example 4 (Corrosion test) In this example, the tests described in Example 3 were continued using stainless steel grade 304. Using the same setup as in Example 3, but using fresh process water from a paper mill, the concentration of the chemicals was increased by a factor of 10. While such high dosages are much higher than realistic dosages in industrial practice, the higher dosages were used to mimic longer contact periods with the chemicals, where increased corrosion would be expected.

[0085] In these tests, the combination of Compound A and MCA was also tested at realistic low doses of 0.08 ppm Compound A and 4 ppm MCA as total active chlorine.

[0086] result The results are shown in Figure 2, which shows the average of results from duplicate reactors run at 55°C for 7 days.

[0087] In all reactors treated with compound A, the corrosion rate of the steel coupons was low, similar to the reactors using process water only. Increasing the MCA concentration by a factor of 10 increased the corrosion. Coupons that were semi-submerged in the MCA treated reactors showed 10.5 times higher corrosion than coupons that were semi-submerged in the compound A treated reactors. Coupons that were in the gas phase in the MCA treated reactors showed 2.5 times higher corrosion than coupons in the gas phase in the compound A treated reactors. The higher level of corrosion in the semi-submerged coupons is due to electrochemical processes at the gas-liquid interface.

[0088] The combination of low MCA dosage and Compound A showed similarly low corrosion rates compared to process water alone.

[0089] These results suggest that effective levels of stabilized chlorine compounds (e.g., MCA) and benzenesulfonyl antimicrobial compounds (e.g., Compound A) for the treatment of biofilms do not cause significant corrosion of stainless steels of the type used in industrial equipment.

Claims

1. (a) an antibacterial compound according to Formula I 【Chemistry 1】 and (b) an antimicrobial system comprising a stabilized chlorine compound, the compounds are separate compounds or comprise a single composition, In the formula, R1, R2, and R3 independently represent a hydrogen atom; a halogen atom; a hydroxy group; an amino group; an alkylamino group, an alkyl group, a hydroxyalkyl group, an acyl group, a haloalkyl group, or an alkoxy group having 1 to 4 carbon atoms; or an acylamide group having 1 to 10 carbon atoms; A represents 2-thiazolamine; 2-propenenitrile; 2-propenoic acid; an alkyl or hydroxyalkyl ester of 2-propenoic acid having 1 to 4 carbon atoms; or a -CHCHCONR5R6 group, where R5 and R6 independently represent a hydrogen atom, an alkyl or hydroxyalkyl having 1 to 4 carbon atoms; The antimicrobial system, wherein the stabilized chlorine compound comprises a reaction product of a reaction between active chlorine and a nitrogen-based reactant selected from ammonium, urea, and dimethylhydantoin.

2. In formula (I), R1 represents a methyl group, an ethyl group, a propyl group, a butyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, or a tertiary butoxy group; R2 and R3 independently represent a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, or a tert-butoxy group; A represents 2-propenenitrile; Or, R1 represents a methyl group, an ethyl group, a propyl group, a butyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, a tert-butoxy group, or an amino group; R2 and R3 independently represent a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, or a tert-butoxy group; 2. The antimicrobial system of claim 1, wherein A represents a -CHCHCONR5R6 group, where R5 and R6 independently represent a hydrogen atom, an alkyl or a hydroxyalkyl having 1 to 4 carbon atoms, and preferably R5 and R6 represent a hydrogen atom.

3. 2. The antimicrobial system of claim 1, wherein the compound according to formula (I) is selected from the group consisting of 3-[(4-methylphenyl)sulfonyl]-2-propenenitrile, 3-phenylsulfonyl-2-propenenitrile, 3-[(4-fluorophenyl)sulfonyl]-2-propenenitrile, 3-[(4-trifluoromethylphenyl)sulfonyl]-2-propenenitrile, 3-[(2,4-dimethylphenyl)sulfonyl]-2-propenenitrile, 3-[(3,4-dimethylphenyl)sulfonyl]-2-propenenitrile, 3-(3,5-dimethylphenyl)sulfonyl-2-propenenitrile, 3-[(2,4,6-trimethylphenyl)sulfonyl]-2-propenenitrile, 3-(4-methoxyphenyl)sulfonyl-2-propenenitrile, 3-[(4-methylphenyl)sulfonyl]prop-2-enamide, 3-[(4-methylphenyl)sulfonyl]prop-2-enoic acid, and any isomers thereof.

4. 4. The antimicrobial system of claim 3, wherein the compound according to formula (I) is selected from the group consisting of 3-[(4-methylphenyl)sulfonyl]-2-propenenitrile, 3-phenylsulfonyl-2-propenenitrile, 3-[(4-trifluoromethylphenyl)sulfonyl]-2-propenenitrile, 3-[(2,4,6-trimethylphenyl)sulfonyl]-2-propenenitrile, 3-(4-methoxyphenyl)sulfonyl-2-propenenitrile, and 3-[(4-methylphenyl)sulfonyl]prop-2-enamide, and any isomers thereof, wherein the compound is preferably 3-[(4-methylphenyl)sulfonyl]-2-propenenitrile.

5. 10. The antimicrobial system of claim 1, wherein the stabilized chlorine compound comprises a reaction product of a reaction between an active chlorine source and a nitrogen-based reactant selected from ammonium salts and urea.

6. 6. The antimicrobial system of claim 5, wherein the stabilized chlorine compound comprises monochloramine.

7. 1. A method for treating industrial process water, the method comprising: (i) administering to a patient an amount of an antimicrobial compound according to Formula I; 【Chemistry 2】 and (ii) administering an amount of a stabilized chlorine compound to the industrial process water; In the formula, R1, R2, and R3 independently represent a hydrogen atom; a halogen atom; a hydroxy group; an amino group; an alkylamino group, an alkyl group, a hydroxyalkyl group, an acyl group, a haloalkyl group, or an alkoxy group having 1 to 4 carbon atoms; or an acylamide group having 1 to 10 carbon atoms; A represents 2-thiazolamine; 2-propenenitrile; 2-propenoic acid; an alkyl or hydroxyalkyl ester of 2-propenoic acid having 1 to 4 carbon atoms; or a -CHCHCONR5R6 group, where R5 and R6 independently represent a hydrogen atom, an alkyl or hydroxyalkyl having 1 to 4 carbon atoms; 1. A method for treating industrial process water, wherein the stabilized chlorine compound comprises the reaction product of a reaction between chlorine and a nitrogen-based reactant selected from ammonium, urea, and dimethylhydantoin.

8. 8. The method of treating industrial process water of claim 7, comprising reducing or preventing microbial growth or reducing or preventing bacterial growth.

9. 10. The method of treating industrial process water of claim 8, comprising reducing or preventing the formation of biofilm and / or reducing or removing formed biofilm.

10. 9. The method for treating industrial process water according to claim 8, wherein the microorganisms are bacteria belonging to the genera Meiothermus, Deinococcus and / or Pseudoxanthomonas.

11. 8. The method for treating industrial process water according to claim 7, wherein the industrial process water comprises cooling water or water containing textile materials.

12. 12. The method for treating industrial process water of claim 11, wherein the industrial process water contains cellulosic fibrous material and is circulated in contact with equipment for producing paper, paperboard, pulp, tissue, molded pulp, nonwovens, or viscose, or equipment for producing pulp, paper, or paperboard.

13. 8. The method of treating industrial process water according to claim 7, wherein the temperature of the industrial process water is at least 40°C, or at least 50°C.

14. 8. The method of treating industrial process water of claim 7, wherein the amount of the antimicrobial compound administered ranges from 0.01 to 100 ppm, 0.01 to 10 ppm, 0.01 to 2 ppm, 0.01 to 1 ppm, 0.01 to 0.5 ppm, or 0.05 to 0.2 ppm, calculated as active compound and based on the volume of the industrial process water.

15. 8. The method of treating industrial process water according to claim 7, wherein the amount of the stabilized chlorine compound administered to the industrial process water is in the range of 0.1 to 5 ppm, 0.1 to 2 ppm, or 0.1 to 1 ppm, calculated as active chlorine and based on the volume of the industrial process water.

16. the antimicrobial compound is continuously administered to the industrial process water; and / or Each compound is added at a different location in the industrial process water; and / or 8. The method of treating industrial process water according to claim 7, wherein the stabilized chlorine compound is administered to an apparatus for producing pulp, paper, or paperboard at a location away from short loops and headboxes.

17. 17. The method of treating industrial process water according to any one of claims 7 to 16, wherein the antimicrobial compound and the stabilized chlorine compound are as defined in any one of claims 2 to 6.

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