HK1124485B - Active bromine containing biocidal compositions and their preparation - Google Patents
Active bromine containing biocidal compositions and their preparation Download PDFInfo
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Description
The application has application number of 200380102335.4, application date of 2003, 10 and 28, and the invention creation name is as follows: active bromine-containing biocide compositions and divisional applications for methods of making the same.
Background
Bromine-based biocides have proven to be more advantageous than chloro-dechlorination for microbiological control of cooling water and disinfection of waste treatment systems. The water treatment industry recognizes the benefits of cost effectiveness control at higher pH values, little loss of biocidal activity when ammonia is present, and effective control of bacteria, algae, and molluscs.
A common method of introducing bromine-based biocides into aqueous systems is through the use of a combination of aqueous NaBr and NaOCl bleaching. The user feeds both materials to a common point whereupon NaOCl oxidizes bromide ions to HOBr/OBr. This activated solution is then introduced directly into the water system to be treated. Feeding both liquids in this manner is necessary because of the HOBr/OBrThe mixture is unstable and has to be produced on site only before introduction into the water. In addition, the supply and metering of the two liquids is cumbersome, especially when the system must be designed to allow time for bromide activation to occur. Thus, many biocide users have shown that for a single feed, bromine-based biocidesAnd (4) demand. The use of elemental bromine and molecular bromine chloride has been considered to meet these requirements. Both are liquid at room temperature and can be fed directly to the water system where hydrolysis to HOBr occurs immediately.
Br2+H2O→HOBr+HBr (1)
BrCl+H2O→HOBr+HCl (2)
The properties of bromine and bromine chloride are compared in table 1.
TABLE 1 physical Properties of bromine and bromine chloride
| Properties of | Bromine (Br)2) | Bromine chloride (BrCl) |
| Appearance of the product | Fuming, dark red liquid | Fuming, red-coloured liquids or gases |
| Boiling point | 59℃ | 5℃ |
| Steam pressure (25 ℃ C.) | 214mm | 1800mm |
| Corrosiveness of | Corrode most metals in the presence of water | Corrode most metals in the presence of water |
It can be seen that certain characteristics of these materials, in particular their corrosiveness, high vapour pressure and tendency to smoke, make it necessary to take care and skill in handling and using them. Early efforts to overcome this material deficiency included complexing bromine with excess bromide ion in the presence of strong acids and stabilizing the resulting solution with ethanolamine. The resulting ethanolammonium perbromide solution contains up to 38 wt% elemental bromine. See US 4886915 to favstitsky in this regard; and US 4966716 to favstriitsky, Hein and Squires.
These solutions allow the use of a single feed to introduce bromine into the water system. For bromine and bromine chloride, ethanolammonium perbromide is hydrolyzed in water to liberate HOBr. These solutions have lower vapor pressures than elemental bromine and bromine chloride. Nevertheless, the solution still has a measurable vapor pressure and therefore tends to produce an undesirable reddish vapor during storage and use.
US 5141652 to Moore et al describes an economically acceptable method of stabilizing aqueous solutions of high concentrations of bromine chloride. A solution is prepared from bromine chloride, water, and a halide salt or hydrohalic acid. These solutions were found to decompose at a rate of less than 30% per year, and at high halide salt concentrations, at a rate of less than 5% per year. In addition, a solution containing 15% elemental bromine equivalents may be prepared. Unfortunately, the relatively high acidity of these solutions and their tendency to be corrosive and fuming have limited their commercial acceptability.
Many solid bromine derivatives, such as BCDMH (1, 3-bromochloro-5, 5-dimethylhydantoin), are limited in the amount of material that can be dissolved in water and supplied to water treatment systems as a liquid. For example, BCDMH has only about 0.15% solubility in water. Another limitation of such derivatives is that when the pH is neutral, HOBr decomposes rapidly, eventually forming bromide ions. Thus, the ability to store and transport these aqueous solutions is greatly limited and commercial viability is problematic.
US3558503 to Goodenough et al describes aqueous solutions of bromine stabilized with various stabilizers and various applications to which such solutions may be put. The compositions described in this patent comprise an aqueous solution of bromine having a bromine number of 0.01 to 100000ppm by weight, wherein the molar ratio of bromine to nitrogen present in the bromine stabilizer is in the range of 2.0: 1 to 0.5: 1. The stabilizers used are biuret, succinimide, urea, lower aliphatic mono-or disubstituted urea containing 2 to 4 carbon atoms in each substituent, sulfamic acid or a compound of the formula RSO3NH2Wherein R is methyl or ethyl. The solution also contains sufficient hydroxide additive to provide a pH of 8 to 10 in the solution, the hydroxide additive being an alkaline earth metal hydroxide or an alkali metal hydroxide.
US 5683654 to Dallmier et al describes the preparation of an aqueous solution of alkali or alkaline earth metal hypobromite by mixing an alkali or alkaline earth metal hypochlorite with a water soluble source of bromide ions to form a labile alkali or alkaline earth metal hypochlorite solution. To this solution is added an aqueous solution of an alkali metal sulfamate, the aqueous solution having a temperature of at least 50 ℃ and being added in an amount such that the molar ratio of alkali metal sulfamate to alkali metal or alkaline earth metal hypobromite is from 0.5 to 6, thereby forming a stable aqueous solution of alkali metal or alkaline earth metal hypobromite. The Dallmier et al patent teaches that much higher levels of sterilizable brine are obtained by this process than by Goodenough et al. However, the Dallmier et al patent recognizes that in their process stabilization must be performed quickly after formation of the unstable NaOBr.
Thus, there is a need for a water-soluble bromine-based biocide that is non-acidic and non-corrosive. There is also a need for a method of disinfecting surfaces and disinfecting water bodies using a single feed, non-acidic and non-corrosive water-soluble bromine-based biocide.
Disclosure of Invention
The present invention provides, inter alia, highly concentrated aqueous biocide solutions containing active bromine which have surprisingly high storage stability, even higher than the stability of the more dilute aqueous biocide solutions currently commercially available which are formed from the same components, assuming, except for the concentration, that they have the same or very similar chemical composition. The present invention also relates, inter alia, to novel high water-soluble solid bromine-containing biocide compositions which are suitable for storage and transportation in solid form and which can be used as effective biocide additives either in solid form for direct addition to industrial or recreational water systems or as raw materials to form aqueous high active biocide solutions or slurries of any desired concentration for addition to industrial or recreational water systems. Thus, the present invention can reduce storage space and transportation costs associated with the production and transportation of highly effective active bromine-containing biocide compositions. In other words, by providing higher concentrations of the aqueous biocide solution or the biocide itself in solid form, the storage space, shipping volume and shipping costs of the biocide product of the invention can be greatly reduced. Furthermore, the surprising improvement in the ideal storage stability of the solid biocide products of the invention and the storage stability of the higher concentration solutions of the invention, as compared to the more dilute commercial solutions, is a further advantage of the invention. It has also been found that the higher concentration biocide compositions of the invention surprisingly have a crystallization temperature equal to or lower than that of the thinner commercial compositions made from the same components.
The invention also provides methods of forming the novel high-concentration active bromine-containing biocide aqueous solutions or slurries of the invention, and methods of forming the novel solid biocide products of the invention.
The preferred high concentration aqueous active bromine compositions of the present invention are solids-free aqueous solutions wherein the active bromine content is greater than 160000 ppm. In other words, the active bromine in these preferred liquid biocides is in solution at room temperature (e.g., 23 ℃).
One embodiment of the present invention is an aqueous biocide composition comprising water, whereinHaving (i) an active bromine content from bromine chloride of greater than 160000ppm (wt/wt), and (ii) an overbased alkali metal salt of sulfamic acid (most preferably the sodium salt), and optionally (but preferably comprising) (iii) an alkali metal halide (preferably sodium chloride or sodium bromide or both), wherein the relative proportions of (i) and (ii) are such that the atomic ratio of nitrogen to active bromine is greater than 0.93, preferably greater than 1 (for example in the range of from greater than 1 to 1.5), and wherein the pH of the composition is at least 7 (for example in the range of from 10 to 13.5, and preferably in the range of from 12.5 to 13.5, or even up to 14). The content of active bromine in the solution is typically in the range of over 160000ppm to 215000 ppm. Preferably, the concentrated liquid biocide solutions of the invention have an active bromine content (whether (a) BrCl, or (b) Br is used)2Or (c) BrCl and Br2Or (d) Br2And Cl2Or (e) BrCl, Br2And Cl2Formed) is in the range of 165000ppm (wt/wt) to 215000ppm (wt/wt), more preferably in the range of 70000ppm (wt/wt) to 215000ppm (wt/wt), and still more preferably in the range of 176000ppm (wt/wt) to 215000ppm (wt/wt).
In a particularly preferred embodiment, the concentrated liquid biocide compositions of the invention have an active bromine content (whether (a) BrCl, or (b) Br is used)2Or (c) BrCl and Br2Or (d) Br2And Cl2Or (e) BrCl, Br2And Cl2Formed) is in the range of 176000ppm to 190000ppm (wt/wt).
In another particularly preferred embodiment, the active bromine content of the liquid biocide composition of the invention (whether (a) BrCl, or (b) Br is used)2Or (c) BrCl and Br2Or (d) Br2And Cl2Or (e) BrCl, Br2And Cl2Formed) is in the range of 201000ppm to 215000 ppm.
It is also preferred to have the atomic ratio of nitrogen to active bromine from (i) and (ii) in the product greater than 1, even when bromine chloride is used in forming the product. In another preferred embodiment, an overbased aqueous solution of an alkali metal salt of sulfamic acid for use in the process is preformed by mixing together in water (1) sulfamic acid and/or an alkali metal salt of sulfamic acid and (2) alkali metal base in proportions such that the proportions of (1) and (2) are such that the feed of the aqueous solution of alkali metal salt of sulfamic acid is capable of maintaining the pH of the aqueous reaction solution at least 7, for example in the range of from 10 to 12 or 12.5, and preferably in the range of from 12.5 to 13.5, during the reaction with one of the above-specified active bromine sources. If sulfamic acid is used as the starting material by itself, it is initially used as a slurry in water with the alkali metal base mixed therewith. If desired, the alkali metal base can be co-fed with the sulfamic acid or alkali metal sulfamate.
Although (a) BrCl, or (b) Br, may be used2Or (c) BrCl and Br2Or (d) Br2And Cl2Or (e) BrCl, Br2And Cl2Either as the active bromine source in the composition of the invention, but preferably bromine chloride, or a mixture of bromine chloride and bromine, especially BrCl and Br used therein2Are greater than 1 because they provide products with very desirable properties and enable efficient plant operation and relatively low plant capital costs.
In one embodiment of the invention, a concentrated liquid biocide composition is provided comprising an aqueous solution of active bromine formed from an overbased aqueous solution of (a) bromine, bromine chloride, or a mixture of bromine chloride and bromine and (b) an alkali metal salt of sulfamic acid, preferably the sodium salt, at a solution pH of at least 7, for example in the range of 10 to 13.5, and preferably in the range of 12.5 to 13.5. The amounts of (a) and (b) used are such that (i) the active bromine content of the concentrated solution is in the range of more than 160000ppm (wt/wt) to 215000ppm (wt/wt), (ii) the atomic ratio of nitrogen to active bromine from (a) and (b) is greater than 1 when bromine is used (i.e., no bromine chloride) and greater than 0.93 when bromine chloride is used (i.e., with or without bromine). In a preferred embodiment, the content of active bromine in the concentrated liquid biocide solution is in the range of 165000ppm (more preferably 176000ppm) to 215000ppm (wt/wt). In a particularly preferred embodiment, the active bromine content of the concentrated liquid biocide solution is in the range of 176000ppm to 190000ppm (wt/wt). In another particularly preferred embodiment, the active bromine content of the concentrated liquid biocide solution is in the range of 201000ppm to 215000 ppm. It is also preferred to use an atomic ratio of nitrogen from (a) and (b) to active bromine of greater than 1, even when bromine chloride is used to form the product. In another preferred embodiment, the aqueous solution of the alkali metal salt of sulfamic acid used in the process is preformed by mixing together in water (i) sulfamic acid and/or alkali metal salt of sulfamic acid and (ii) alkali metal base in proportions such that the aqueous solution of the alkali metal salt of sulfamic acid formed has a pH of at least 7, for example in the range of 10 to 12 or 12.5, and preferably in the range of 12.5 to 13.5 or 14. If sulfamic acid is used as the starting material by itself, it is initially used as a slurry in water with the alkali metal base mixed therewith.
In one embodiment of the invention there is provided a process for the production of a concentrated liquid biocide composition which comprises mixing (a) bromine and (b) an aqueous overbased alkaline solution of an alkali metal salt (preferably the sodium salt) of sulfamic acid, the solution having a pH of at least 7, typically at least 10, desirably at least 12, for example in the range 12 to 14, and preferably in the range 12 to 13.5 or 14. The amounts of (a) and (b) used should be such that (i) the content of active bromine in the solution is as described above and (ii) the atomic ratio of nitrogen to active bromine from (a) and (b) is greater than 1. In a preferred embodiment, the aqueous solution of the alkali metal salt of sulfamic acid used in the process is preformed by mixing together in water (i) sulfamic acid and/or alkali metal salt of sulfamic acid and (ii) alkali metal base in proportions such that an aqueous solution of the alkali metal salt of sulfamic acid having a pH of at least 12 is formed. If sulfamic acid is used as the starting material by itself, it is initially used as a slurry in water with the alkali metal base mixed therewith.
The invention also provides a solid bromine-containing biocide composition formed by removing water from an aqueous solution or slurry of a product formed in water from (a) and (B), wherein (a) is (i) bromine, (ii) bromine chloride, (iii) a mixture of bromine chloride and bromine, (iv) Br2To Cl2Bromine and chlorine in a molar ratio of at least 1 or (v) ratioExample to enable total Br2To Cl2Bromine chloride, bromine and chlorine in a molar ratio of at least 1, and (B) is (i) an alkali metal salt of sulfamic acid and/or sulfamic acid and (ii) an alkali metal base, wherein the aqueous solution or slurry has a pH of at least 7 and the atomic ratio of nitrogen to active bromine from (a) and (B) is greater than 0.93. The concentration of the product formed from (a) and (B) in water used to form the solid bromine-containing biocide composition is not critical; any concentration may be present in the initial aqueous solution or slurry. It is, of course, desirable to start with a higher concentration solution or slurry, as this can reduce the amount of water that must be removed in preparing the solid bromine-containing biocide composition.
The solid bromine-containing biocide compositions of the invention are preferably formed by spray drying an aqueous solution or slurry of the product formed from (a) and (B). The temperature of the atmosphere (e.g. dry air or nitrogen) introduced into the spray is typically in the range of 20-100 c, preferably in the range of 20-60 c, especially when the process is carried out under reduced pressure. When spray drying is used, it is preferred to use the product formed from (a) and (B) as a solution rather than as a slurry, as this minimises the possibility of nozzle blockage. On the other hand, if water is to be flashed off or otherwise distilled from a solution or slurry of the product formed from (a) and (B), it is preferred to use the product formed from (a) and (B) as a slurry rather than a solution, as this minimizes the amount of water to be removed. This flash or distillation may be, and preferably is, carried out at reduced pressure to reduce the temperature to which the product formed from (a) and (B) is exposed during drying.
The solid bromine-containing biocide compositions of the invention are typically in the form of a powder or relatively small particles. However, the solid bromine-containing biocide compositions of the invention can be compressed into larger forms, such as small blocks, granules, pellets, tablets or discs, using known methods. Such a compressed product may be formed using a binder or other material that enables the particles to adhere to one another. If the adhesive used is not readily soluble in water, it is important not to completely coat the product with a water impermeable coating of such adhesive which remains intact under actual use conditions, as this will prevent contact between the coated bromine-containing biocide composition and the water to be treated with the biocide composition. The coated product is used in water at a temperature high enough to melt away the coating and binder so that the water can contact the previously coated biocide composition itself, in which case a low melting wax or the like can be used to bind and even coat the bromine-containing biocide composition. However, it is preferred to use a binder which is water soluble or which provides effective binding but in insufficient proportions to coat the particles which are bound together. The binder used should be compatible with the solid bromine-containing biocide composition of the invention.
Another embodiment of the invention is a method of disinfecting a surface having a biofilm thereon, which method comprises introducing into the water in contact with or contactable with said biofilm a biocidally effective amount of a concentrated aqueous biocide solution or slurry formed from an overbased aqueous solution of bromine chloride and an alkali metal salt of sulfamic acid, preferably the sodium salt, such composition having an active bromine content of greater than 160000ppm (wt/wt), a pH of at least 7 (e.g. in the range of 7 to 13.5 or even 14, typically in the range of 10 to 13.5, preferably in the range of 12.5 to 13.5) and a nitrogen to active bromine atomic ratio of greater than 0.93 and preferably greater than 1. This atomic ratio in the process is based on the amount of bromine chloride and alkali metal sulfamate used in forming the concentrated aqueous biocide solution or slurry. The water treated according to this embodiment may contain, and typically contains, planktonic bacteria, and a biocidally effective amount of a concentrated aqueous biocide solution or slurry added to the water should be sufficient to control such bacteria and biofilm. In this embodiment, it is preferred to use concentrated aqueous biocide solutions with active bromine content greater than 160000ppm, which are solids free, but slurries are also effective. The content of active bromine in the solution is typically in the range of over 160000ppm to 215000 ppm. Preferably, the concentrated liquid biocide solution used in this embodiment has an active bromine content (whether (a) BrCl or (b) Br is used)2Or (c) BrCl and Br2Or (d) Br2And Cl2Or (e) BrCl, Br2And Cl2Active bromine formation) is in the range of 165000ppm (wt/wt) to 215000ppm (wt/wt), more preferably 170000ppm(wt/wt) to 215000ppm (wt/wt), still more preferably 176000ppm (wt/wt) to 215000ppm (wt/wt). In a particularly preferred embodiment, the content of active bromine in the concentrated liquid biocide composition for biofilm control (whether (a) BrCl, or (b) Br is used)2Or (c) BrCl and Br2Or (d) Br2And Cl2Or (e) BrCl, Br2And Cl2Active bromine formation) is in the range of 176000ppm to 190000ppm (wt/wt). In another such particularly preferred embodiment, a liquid biocide composition is used which has an active bromine content (whether (a) BrCl, or (b) Br is used)2Or (c) BrCl and Br2Or (d) Br2And Cl2Or (e) BrCl, Br2And Cl2Formed) is in the range of 201000ppm to 215000 ppm.
Yet another embodiment of the present invention is a method of disinfecting a water body, such as a recreational water body, an industrial water body, a wastewater body, or a process water body, comprising introducing into such water a biocidally effective amount of a concentrated aqueous biocide solution or slurry, as described immediately in the preceding paragraph.
Yet another embodiment of the present invention is a method of disinfecting a surface having a biofilm thereon, the method comprising introducing a biocidally effective amount of the solid bromine-containing biocide composition of the present invention into water that is in contact with or contactable with the biofilm. It is recalled that such solid compositions are formed by removing water from an aqueous solution or slurry of a product formed in water from (a) bromine, (ii) bromine chloride, (iii) a mixture of bromine chloride and bromine, (iv) Br2To Cl2Bromine and chlorine in a molar ratio of at least 1, or (v) in a ratio such that total Br is2To Cl2Bromine chloride, bromine and chlorine in a molar ratio of at least 1, and (B) is (i) an alkali metal salt of sulfamic acid and/or sulfamic acid and (ii) an alkali metal base, wherein the aqueous solution or slurry has a pH of at least 7 and the atomic ratio of nitrogen to active bromine from (a) and (B) is greater than 0.93. The concentration of the product formed from (a) and (B) in water used to form the solid bromine-containing biocide composition is not critical; in the initial water dissolvingAny concentration may be present in the liquid or slurry. It is, of course, desirable to start with a higher concentration solution or slurry, as this can reduce the amount of water that must be removed when preparing the solid bromine-containing biocide composition. The water treated according to this embodiment may contain, and typically contains, planktonic bacteria, and a biocidally effective amount of a concentrated aqueous biocide solution or slurry added to the water should be sufficient to control such bacteria and biofilm.
Yet another embodiment of the present invention is a method of disinfecting a water body, such as a recreational water body, an industrial water body, a wastewater body, or a process water body, comprising introducing into such water a biocidally effective amount of a solid bromine-containing biocide composition of the present invention, as described immediately in the preceding paragraph. In a preferred embodiment, the water being treated is in a subterranean well being used, or in a subterranean hole drilled in connection with an oil or gas field operation. In such treatments, the solid bromine-containing biocide compositions of the invention can be easily introduced into groundwater by gravity and can efficiently kill not only the commonly common biofilm and planktonic organisms, but also sessile bacteria, thereby preventing well souring. In carrying out the methods described in this paragraph, it is also possible to use a biocidally effective amount of the concentrated aqueous biocide solution or slurry of the present invention, and such methods of using such concentrated aqueous biocide solution or slurry therefore constitute further embodiments of the present invention.
In all embodiments of the invention, the alkali metal content of the alkali metal salt of sulfamic acid and of the alkali metal base used in forming the composition of the invention is preferably potassium, more preferably sodium.
The above and other embodiments of the invention will be more apparent from the ensuing description and appended claims.
Further detailed description
When introducing a bromine source such as bromine chloride or bromine into an aqueous solution of an alkali metal salt of sulfamic acid, it is desirable to maintain the desired pH of the resulting solution at 7 or above by also introducing (continuously or intermittently as necessary) additional alkali metal base into the solution, such as by co-adding an aqueous solution of an alkali metal base. When storing the concentrated aqueous solution in the drum, it is desirable that such a solution has a pH of 10 or more, and preferably in the range of 12.5 to 13.5. The pH can be as high as 14 if desired.
Bromine chloride (or a mixture of bromine chloride and bromine wherein less than 50 mol% of the mixture is bromine) is preferably used as the active bromine source in the above process because in the resulting aqueous composition all of the bromine in the bromine chloride is made available as active bromine which provides biocidal activity in solution. In other words, the chlorine of the bromine chloride is converted to a dissolved alkali metal chloride salt in the process, thereby releasing bromine as an active bromine inclusion in the biocide composition capable of providing biocidal activity. Thus, the more expensive component of bromine chloride, namely bromine, is fully utilized in forming the active bromine in the aqueous biocide composition, while the less expensive component of bromine chloride, namely the anionic chlorine, makes this benefit possible.
The general procedure for preparing the compositions of the present invention using sulfamic acid includes as a first step forming a slurry of sulfamic acid in water. Typically, the pH of such a slurry is below 1pH unit. Then 50% strength sodium hydroxide was added until the solid was completely dissolved. Additional 50% NaOH was added until the desired pH was reached. A bromine source, such as bromine or bromine chloride, is then added at a rate to dissolve the bromine and react with the sulfamic acid without forming a halogen pool at the bottom of the reactor. On a laboratory scale, a convenient addition rate is about 2 drops/second. Sodium hydroxide (e.g., 25% or 50%) is co-fed to the reactor to maintain the desired pH (e.g., in the range of 7 to 13.5), and may be operated at a pH even in the range of 13.5 to 14. It has been found that stable solutions containing up to 26% active bromine (11.5% as active chlorine) can be prepared by the process of the present invention. While solutions containing up to 26% active bromine (i.e., 260000ppm wt/wt) are sufficiently stable for use in contemporary laboratory tests, compositions containing over the range of 160000ppm (wt/wt) to 215000ppm (wt/wt) of active bromine not only have superior stability compared to compositions containing amounts of active bromine well above this range, but also additionally have superior stability compared to compositions containing amounts of active bromine well below this range for commercial purposes where the product must be stored and transported off-site.
The term "active bromine" in the process refers to all bromine-containing species that are capable of biocidal activity. It is generally accepted in the art that all bromine in the +1 oxidation state is biocidally active and is therefore included in the term "active bromine". Bromine, bromine chloride, hypobromous acid, hypobromite ion, hydrogen tribromide, tribromide ion, and organo-N-brominated compounds are well known in the art as bromine having an oxidation state of + 1. These and other such species present within this range therefore constitute the active bromine content of the compositions of the present invention. See, for example, US 4382799 and US 5679239. A very well established method in the art for determining the amount of active bromine in solution is starch-iodine titration, which determines all of the active bromine in a sample, regardless of the species that may constitute the active bromine. The effectiveness and accuracy of classical starch-iodine methods for the quantitative determination of bromine, as well as many other oxidants, have long been known, as evidenced by the evidence of Chapter XIV of Willad-Furman, Elementary quantitative analysis, Third Edition, D.Van Nostrand Company, Inc., New York, Copyright 1933, 1935, 1940.
A typical starch-iodine titration method was performed to determine active bromine as follows: a magnetic stirrer and 50 ml of glacial acetic acid were placed in an iodine vial. A sample (usually 0.2-0.5g) to be tested for active bromine was weighed and added to a flask containing acetic acid. Water (50 ml) and aqueous potassium iodide (15% (wt/wt); 25 ml) were then added to the flask. The flask was stoppered with water. The solution was then stirred for 15 minutes, then the stopper of the flask was removed and the stopper and sealed area were rinsed into the flask with water. An automatic burette (Metrohm Limited) was charged with 0.1 standard sodium thiosulfate. Titrate the solution in the iodine vial with 0.1 standard sodium thiosulfate; when a pale yellow color was observed, 1 ml of 1% aqueous starch solution was added to change the color of the solution in the flask from pale yellow to blue. Titration with sodium thiosulfate was continued until the blue color disappeared. The amount of active bromine was calculated using the weight of the sample and the volume of the titrated sodium thiosulfate solution. Thus, the amount of active bromine in the compositions of the present invention can be determined quantitatively, regardless of the actual chemical form.
By using bromine or bromine chloride with caustic in a stabilized bromine composition, higher levels of active halogen can be obtained than can be obtained by adding sodium hypochlorite to sodium bromide. The process and resulting composition also have an active bromine content that is about twice that of the most concentrated solutions produced according to the Goodenough patents mentioned above. Furthermore, even at high active bromine levels, it has been found that biocide compositions can be provided which are capable of maintaining these high active bromine levels for at least two months and which exhibit no visible or objectionable vapors or odors during this period.
The high concentration aqueous active bromine-containing biocide solutions of the present invention were found to have surprisingly high storage stability, even higher than the more dilute biocide concentrates currently commercially available, formed from the same components, in which the same or very similar chemical composition is assumed except for the concentration. For example, by obtaining StabroomA commercial sample of 909 biocide (Albemarle Corporation), water removed therefrom under vacuum and the resulting product characterized to produce a sample having a higher active bromine concentration than those products sold commercially by Albemarle Corporation. Details of this experimental work are set forth in the illustrative examples below.
Example 1
To a 1000mL round bottom flask equipped with a thermometer, water condenser and water bath was added 800g of Stabroom 909 biocide. This original commercial sample had an active bromine content of 14.82%, as determined by the KI/thiosulfate method. In other words, a sample of this commercial product had an active bromine content of 148200ppm (wt/wt). The water bath was heated with a magnetic stirrer/heater and a 28mm vacuum was applied to the apparatus. The water is distilled off at a bath temperature of 48-57 ℃ and 29-32 ℃. Distillation was stopped after 45 minutes. The amount of product remaining in the distillation flask was 668 g. Analysis by the KI/thiosulfate method showed 17.87% active bromine. In other words, the analysis indicated that the active bromine content of this partially dehydrated composition was 178700ppm (wt/wt).
Example 2
The procedure of example 1 was followed. 1000g of Stabroom 909 biocide was added to the round bottom flask. The water is distilled out at the bath temperature of 42-55 ℃ and the temperature of 31-33 ℃. The distillation was stopped after 2.5 hours. The amount of product remaining in the distillation flask was 692 g. Analysis of this partially dehydrated product by the KI/thiosulfate method indicated an activity of 21.19% of active bromine, i.e., indicating that the active bromine content of this composition was 211900ppm (wt/wt).
Example 3
The stability of the highly concentrated compositions of the present invention formed in examples 1 and 2 were compared to the more dilute starting samples. A sample of the product of example 1 was poured into one 8 ounce jar of polyethylene, a sample of the product of example 2 was poured into another 8 ounce jar of polyethylene, and a sample of the starting thinner Stabrom 909 biocide concentrate was poured into a third 8 ounce jar of polyethylene. Each bottle was filled to about half of its total volume. The bottles were loosely covered and placed in a circulating air oven maintained at 45 ℃. Samples were removed periodically and analyzed for activity (i.e., active bromine content). Table 2 summarizes the data. The half-life data shown in table 2 were calculated from the slope of the least-squares line obtained by plotting the data in the form of ln (activity at time ═ t)/(activity at time ═ 0) versus time. This represents a first order kinetic analysis of the data. For more information on this technology, reference may be made to Arthur Adamson, A Textbook of Physical Chemistry, page 617-620, Academic Press, NY, 1973. The data from these experiments show that the samples from examples 1 and 2 have excellent storage stability with half-lives exceeding those of commercial materials. Thus, even more concentrated, the compositions of the present invention have even greater stability than less concentrated commercial compositions.
In table 2, the values shown for the control (Stabrom 909 biocide) and the compositions of example 1 and example 2 are in wt% of active bromine. Thus, the value of 14.86 wt% is equivalent to 148600ppm (wt/wt).
TABLE 2
| Days at 45 ℃ | Control, wt.% | Example 1, wt.% | Example 2, wt.% |
| 0 | 14.86 | 17.81 | 21.25 |
| 7 | ---- | ---- | 20.87 |
| 8 | 14.5 | 17.48 | ---- |
| 14 | ---- | ---- | 20.46 |
| 23 | 14.02 | 16.95 | ---- |
| 28 | ---- | ---- | 19.74 |
| 42 | 13.23 | 16.29 | 19.09 |
| Half-life (days) | 254 | 328 | 272 |
Example 4
The crystallization temperatures of the high activity active bromine samples of examples 1 and 2 were compared to the starting sample (control). Generally, the following methods are used: the glass tube containing 30mL of sample was mechanically stirred while cooling. At 10 c above the expected freezing point temperature, the sample was cooled at a rate of about 0.5 c/min until crystal formation was observed. The temperature was recorded for 10 minutes after crystal formation. Pour point tube containing sample was placed into ethylene glycol bath. The sample was left at one temperature for 8 hours. If the sample does not freeze, the bath temperature is lowered by 10 degrees. The test was continued until the sample solidified.
More specifically, the steps used in the method are as follows:
1) approximately 30mL of sample was measured into a jacketed glass tube.
2) To the sample was added 0.03g of cullet as a seed material.
3) A rubber stopper/thermometer/helical stirrer assembly was inserted into the sample. (the tip of the probe should be located about 0.5 inches from the bottom of the tube).
4) The tubes were supported in a cooling bath until the levels of sample and acetone were approximately equal.
5) The second temperature probe was fixed in the acetone bath so that it did not contact the bottom or side.
6) Stirring of the sample was started and the addition of dry ice to the acetone bath was started slowly and carefully. The stirrer was kept in the sample while stirring. Avoiding removal of the stirrer from the sample. This will result in the formation of air bubbles in the sample.
7) The observed temperature started to decrease on the thermometer display. The temperature of the sample in the tube will decrease at a fairly even rate. The cooling rate should be maintained at about 0.5 c/min at about 10 c above the expected freezing point.
8) Continue cooling and monitor temperature. The samples were monitored when all samples had crystallized. The freezing point temperature should be stable temporarily (10-20 seconds). If supercooling is significant, the freezing temperature is taken when the temperature becomes stable after the temperature is raised. If the sample did not crystallize at-46 deg.C, the test was stopped.
9) The sample was checked for crystal return to solution after warming to room temperature.
The crystallization temperature of the higher concentration compositions of the present invention is equal to or desirably lower than the crystallization temperature of the commercial material. Table 3 summarizes the data.
TABLE 3
| Stabrom 909 | Example 1 | Example 2 | |
| Crystallization temperature of | -4 | -3 | -11 |
The following examples show that samples with even higher initial activity can be prepared. Tests have shown that these samples are less stable than those prepared above and may solidify when stored at room temperature.
Example 5
The procedure of example 1 was followed. 814g Staboom 909 biocide was added to the round bottom flask. The water is distilled out at the bath temperature of 42-52 ℃ and the temperature of 31-33 ℃. The distillation was stopped after 3.5 hours. KI/thiosulfate analysis showed an activity of 20.08% (200800ppm, wt/wt) of active bromine at this point. The distillation was restarted the next day and continued for an additional 1.5 hours. The amount of product remaining in the distillation flask was 578 g. It is dark orange with a small amount of white solid. The product was filtered through a fritted glass funnel to give 541g of filtrate. KI/thiosulfate analysis showed 21.74% active bromine.
Example 6
The procedure of example 1 was followed. To a round bottom flask was added 1002g of Stabrom 909 biocide. The water is distilled off at a bath temperature of 43-59 ℃ and at a temperature of 30-37 ℃. The distillation was stopped after 5 hours. The amount of product remaining in the distillation flask was 602 g. It consisted of a white solid and a dark orange oil. The product was filtered through a fritted glass funnel to give 438g of filtrate and 145g of an off-white solid. The KI/thiosulfate method showed that the bright and dark orange solution had 24.10% active bromine and the solid had 28.09% active bromine.
Example 7
The stability of the high activity BrCl samples from examples 5 and 6 was compared to the starting sample (control). About 100g of the liquid product was poured into each of three 4 oz wide-mouth polyethylene bottles. About 20g of the solid sample from example 6 was placed in a 4 oz wide-mouth polyethylene bottle. The bottles were loosely covered and placed in a circulating air oven at 47 ℃. Samples were removed periodically and analyzed for activity. Table 4 summarizes the data. The values for the control (Stabrom 909 biocide) and the compositions of examples 5 and 6 shown in table 1, table 4 are in wt% of active bromine. Thus, a value of 15.12 wt% is equivalent to 151200ppm (wt/wt). Similarly, half-life data was calculated from the slope of the least-squares line obtained by plotting data in the form of ln (activity at time-t)/(activity at time-0) against time. The data indicate that these samples at even higher concentrations have lower storage stability than the starting material.
TABLE 4
| Days at 47 ℃ | Control, wt.% | Example 5, wt.% | Example 6, solution, wt.% | Example 6, solids,% by weight |
| 0 | 15.12 | 21.70 | 24.06 | 27.84 |
| 9 | 14.76 | 19.45 | 20.28 | 24.82 |
| 21 | 14.35 | 16.99 | 16.95 | 20.46 |
| 42 | 13.73 | 14.63 | 12.63 | 13.07 |
| 56 | 13.37 | 13.67 | 10.65 | 10.64 |
| Half-life (days) | 303 | 60 | 42 | 47 |
Example 8
Samples of the highly active BrCl product from examples 5 and 6 were stored at room temperature (about 23 deg.C) in the dark. Samples were removed periodically and analyzed for activity. Table 5 summarizes the data. The data show that the very high concentration samples in turn have lower storage stability compared to the Stabrom 909 biocide samples. The liquid sample from example 6 solidified after storage at room temperature for several weeks. The coagulated sample was heated to re-liquefy prior to analysis.
TABLE 5
| Days at RT | Stabrom 909，wt％ | Example 5, wt.% | Example 6, solution, wt.% | Example 6, solids,% by weight |
| 0 | 15.12 | 21.70 | 24.06 | 27.84 |
| 35 | 15.03 | 21.52 | 23.30 | 27.89 |
| 70 | 14.93 | 21.32 | 23.36 | 27.13 |
| Half-life period (week) | 537 | 385 | 237 | 270 |
It will be appreciated that the highly concentrated aqueous biocide solutions containing active bromine of the present invention can be prepared directly without dehydration operations by appropriate partitioning of the amount of water in the reaction between (a) bromine, bromine chloride, or a mixture of bromine chloride and bromine and (b) an overbased aqueous solution of an alkali metal salt of sulfamic acid. Thus, compositions of the present invention having a dissolved active bromine content in the range of from over 160000ppm (wt/wt) to 215000ppm (wt/wt) can be prepared directly by mixing the components (a) and (b) in the appropriate proportions. The dehydration procedure applied to Stabrom 909 biocide in examples 1, 2, 5 and 6 was used only for convenience, as this avoided the need for additional synthetic reactions to prepare the samples for evaluation.
As noted above, another aspect of the present invention is the discovery that new solid bromine-containing biocide compositions can be prepared that are suitable for storage and transportation in solid form and can be used as effective biocide additives, added directly to industrial or recreational water systems in solid form, or added as a raw material to industrial or recreational water systems in the form of a highly active biocide aqueous solution or slurry of any desired concentration. Such novel compositions may be formed by removing water from an aqueous solution or slurry of the derivative product of (i.e., the product formed therefrom) bromine, bromine chloride, or a mixture of bromine chloride and bromine and (b) an overbased solution of an alkali metal salt of sulfamic acid. If the solution or slurry is heated, the resulting particulate solid product tends to have a lower storage stability than the currently marketed aqueous Stabroom 909 concentrate, but as long as the temperature is not too high, the storage stability of the solid is sufficient for short term storage. In a preferred embodiment of the present invention, there is provided a spray-dried product formed from (a) bromine, bromine chloride, or a mixture of bromine chloride and bromine and (b) an overbased aqueous solution of an alkali metal salt of sulfamic acid, preferably the sodium salt of sulfamic acid. Evaporation of water from the spray droplets provides a local cooling effect on the particles, so that solids can form at temperatures below the temperature of the atmosphere in which they form. The spray dried product of the present invention will have better stability if removed from a heated environment and maintained at ambient room temperature than if the solid formed from water was evaporated from a non-sprayed solution or slurry at the same temperature as used in the spray drying operation. Typically, the spray-dried solid product of the invention is prepared using atmospheric temperature, wherein the solution (or slurry) is sprayed in the range of 20-100 ℃ and preferably in the range of 20-60 ℃. The average residence time of the solids in the heated spray-drying zone is preferably kept short, for example in the range from 1 to 30 minutes, and preferably in the range from 1 to 10 minutes. Generally, the higher the temperature, the shorter the residence time. Spray drying may be carried out in a zone where the reduced pressure is maintained, which enables spray drying without the need for heating.
One preferred application of the novel solid bromine-containing biocide compositions of the present invention is as a biocide for subterranean applications in oil field operations. For this use, the present invention provides as an article of manufacture a package consisting of a water-soluble container (preferably a water-soluble pouch) (a) containing (B) a solid bromine-containing biocide composition formed by removing water from an aqueous solution or slurry of a derivative product of (a) bromine, bromine chloride, or a mixture of bromine chloride and bromine (preferably (i) bromine chloride or (ii) a mixture of bromine chloride and bromine, less than 50 mole% of which is bromine in the mixture), (B) an overbased aqueous solution of an alkali metal salt of sulfamic acid (preferably a sodium salt of sulfamic acid). Such solid bromine-containing biocide compositions are preferably in the form of water-soluble particles, granules, pellets or powders. The size of such particles, granules, pellets or powder is not critical. It is required that the solid dissolves at a reasonably rapid rate (e.g. within 30 minutes on contact with water at a temperature of at least 20 ℃). In a preferred embodiment, the solid bromine-containing biocide composition of (B) in such a package is a spray-dried product as described above.
Examples 9 and 10 serve to illustrate the formation of solid bromine-containing biocide compositions of the invention.
Example 9
This example simulates a spray drying operation that can be performed on Stabrom 909 biocide or any other aqueous solution or slurry of the product formed from (a) bromine, bromine chloride, or a mixture of bromine chloride and bromine, and (b) an overbased aqueous solution of an alkali metal salt of sulfamic acid. A sample of stabroom 909 biocide (1.50g, activity ═ 15.10% active bromine) was added as a dispersed drop to a crystallization dish. The dishes were placed in a recirculation oven set at 40 ℃ overnight. The next day, the solution was semi-solid. The semi-solid was treated with a spatula to expose the interior of the drop to air. The material was placed back into the furnace for an additional 5 hours. A yellow slightly waxy solid (0.65g) was obtained. The activity of the solid was 33.24% active bromine. After 3 days of storage at room temperature in the dark, the activity of the solid was 33.38% active bromine. After 14 days of storage at room temperature in the dark, the activity of the solid was 33.23% active bromine.
Example 10
The procedure of example 9 was repeated on a larger scale. Staboom 909 biocide sample (4.00g) was added as a dispersed drop to a crystallizing dish. The dishes were placed in a recirculation oven set at 40 ℃ overnight. The next day, the solution was semi-solid. The semi-solid was treated with a spatula to expose the interior of the droplet to air. The material was placed back into the furnace for an additional 24 hours. A yellow slightly waxy solid (2.18g) was obtained. The activity of the solid was 31.99% active bromine. After 7 days of storage at room temperature in the dark, the activity of the solid was 32.27% as active bromine. After 82 days of storage at room temperature, the activity of the solid was 30.75% active bromine.
The data in examples 9 and 10 are used to illustrate the satisfactory stability of the solid product produced by the simulated spray drying technique. Due to the relatively long exposure of the solids to 40 ℃, especially in example 10, the formation of solids exposed to the drying temperature for a shorter time in a practical spray dryer should provide spray-dried products of the invention with very desirable storage stability, especially if the solids are protected against exposure to excessive heat and exposure to light during storage.
For convenience, the solid bromine-containing biocide compositions of the invention may also be referred to as sulfamate-stabilized active bromine-containing solids. In one embodiment of the invention, the sulfamate-stabilized active bromine-containing solid is in the form of a powder or finely divided particles. In another embodiment of the invention, the sulfamate-stabilized active bromine-containing solid is in the form of a shape consisting of agglomerated or compressed particles. Examples of such shapes include nublets, granules, caplets, tablets, briquettes (briquettes), or pucks (pucks). While there are no hard fixed rules governing the differences in size between the pieces, granules, caplets, tablets, agglomerates, or discs, in general the pieces and granules are considered to be particles typically in the size range of 80-3 U.S. standard mesh sizes. Typically, the caplet has a length in the range of 0.5-1 inch and a cross-sectional width in the range of 0.25-0.5 inch. Typically, the sheet has a diameter in the range of 0.5-1.0 inches and a thickness in the range of 0.5-1.0 inches. Typically, the agglomerate sizes range from 0.5 to 4.0 inches in length, 0.5 to 4.0 inches in width, and 0.5 to 2.5 inches in height. The disks are normal disk-like objects up to 3.0 inches in diameter and in the range of 0.5-1.0 inches thick. For purposes of the present invention, the powder and granular forms of the sulfamate-stabilized active bromine-containing solids of the present invention are considered to have particle sizes below 80 U.S. standard mesh size. It is to be understood and appreciated that the above dimensions are merely illustrative and are not intended to unduly limit the scope of the present invention.
The active bromine-containing solid stabilized by the powdery or granular solid sulfamate of this invention can be formed into small pieces, granules, tablets or other compressed shapes such as briquettes and disks using conventionally known processing equipment and, to a maximum extent, using known procedures. However, in carrying out the compaction of the mixture of the invention, it is important that the compaction pressure be sufficient to cause interparticle adhesion of the particles to one another, whether or not a binder is used, and may be accompanied by plastic deformation of some, if not all, of the particles. At the same time, the compaction pressure should not be so great as to produce a layered compacted product. Typically, suitable compaction pressures are in the range of 1000 to 30000psi, preferably in the range of 5000 to 25000 psi. Such compaction may be performed using, for example, a rotary tablet press operating at conventional rotational speeds. Another method of accomplishing compaction is through die orifices using pressure extrusion while shearing the extrudate to produce a compacted shape of the desired dimensions. In such an operation, the compaction pressure within the die should be sufficient to cause plastic deformation and interparticle adhesion of the particles, but should be insufficient to produce a compacted product that undergoes substantial elastic recovery when extruded resulting in delamination of the compacted extrudate.
Finely divided waxes such as finely divided paraffin waxes and chloroparaffins which are compatible with the sulfamate-stabilized active bromine-containing solids of the invention can be used as binders for forming the compressed shapes of the invention. Certain inorganic salts may also be used to help form the compressed or compacted solids of the present invention.
Additionally, various micronized synthetic waxes may be used as binders in the formation of compacted or compressed tablets, granules, tablets or other compressed shapes such as briquettes and discs from the powdered or granular solid sulfamate-stabilized active bromine-containing solid of the present invention. Such micronized waxes are typically micronized polyolefin waxes or micronized polyfluorocarbon waxes, or mixtures thereof. Although the average particle size of the wax may vary within reasonable limits, preferred micronized waxes typically have an average particle size of no greater than 15 microns prior to compaction. Also, preferred micronized waxes typically have a maximum particle size of no greater than 40 microns prior to compaction. In most cases, the bulk density of the micronized wax prior to compaction is in the range of 0.9 to 1.4g/cc at 25 ℃. Another characteristic of the preferably micronized waxes is that they at least partially melt at temperatures in the range of 100 ℃ to 150 ℃.
Among the particularly preferred micronized polyethylene waxes are those which, before compaction, have the following characteristics: (a) melting at a temperature in the range of 109 ℃ to 111 ℃, or (b) having an average particle size in the range of 6.0 to 8.0 microns, or (c) having a maximum particle size of about 22 microns, or (d) having a combination of any two or all three of (a), (b), and (c).
Particularly preferred polypropylene waxes include those characterized by the following prior to compaction: (a) a melting temperature in the range of 140 ℃ to 143 ℃, or (b) an average particle size in the range of 5.0 to 7.0 microns, or (c) a maximum particle size of about 22 microns, or a combination of any two or all three of (a), (b), and (c).
Particularly preferred micronized wax mixtures include micronized polyolefin and polyfluorocarbon wax mixtures that at least partially melt at temperatures in the range of 104 ℃ to 126 ℃ prior to compaction. Wherein these mixtures are those having the following characteristics before compaction: (a) partially melt at a temperature in the range of 104 ℃ to 110 ℃, or (b) have an average particle size in the range of 5-7 microns, or (c) have a maximum particle size of about 22 microns, or (d) have a combination of any two or all three of (a), (b), and (c). Wherein these mixtures also include those having the following characteristics before compaction: (a) partially melt at a temperature in the range of 124 ℃ to 126 ℃, or (b) have an average particle size in the range of 9-11 microns, or (c) have a maximum particle size of about 31 microns, or (d) have a combination of any two or all three of (a), (b), and (c).
Other particularly preferred micronized waxes are modified polyfluorocarbon waxes having the following characteristics before compaction: (a) partially melt at a temperature in the range of 108 ℃ to 115 ℃, or (b) have an average particle size in the range of 5-6 microns, or (c) have a maximum particle size of about 22 microns, or (d) have a combination of any two or all three of (a), (b), and (c).
In forming the compacted or compacted shape, a dry powder mixture of the powdered or granular solid sulfamate-stabilized active bromine-containing solid of the present invention and one or more binders is formed and compacted or compacted. Various methods may be used in forming such dry mixtures of the present invention. The preferred method is to use a ribbon blender or drum blender to mix the powdered or finely divided particulate solid sulfamate-stabilized active bromine-containing solid with a binder such as micronized wax. Such equipment is readily available in the market from many well-known suppliers. The amount of binder, e.g., micronized wax, in the dry mixture of the present invention is in the range of 0.5 to 10 weight percent, preferably in the range of 1 to 5 weight percent, based on the total weight of solid sulfamate-stabilized active bromine-containing solids and binder. It will be understood and appreciated that departures from these ranges are permissible without departing from the scope of the invention, so long as such departures are deemed necessary or appropriate.
When the powdered or granular solid sulfamate-stabilized active bromine-containing solid of the present invention is compacted with or without one or more binders, it is desirable, but not necessary, to apply a pressure agglomeration lubricant to the compaction surface of the tool to reduce the coefficient of friction between the compacted material and the tool. When such lubricants are used, any of the various lubricants conventionally used therefor may be used, such as suitable finely divided waxes and the like.
The bits, particles, flakes, agglomerates, or discs of the present invention have particular utility as biocides for treating swimming pools, spas, decorative fountains, toilet bowls, urinals, cooling towers, air scrubber systems, wastewater, liquids used and formed in pulp and paper processing operations, and liquids used and formed in oil field applications such as secondary oil field recovery operations, particularly operations involving seawater irrigation.
In another embodiment, the alkali metal dichlorohypobromite M [ BrCl ] is preformed by premixing bromine chloride and aqueous sodium chloride solution2](M ═ alkali metal) and bromine chloride is used in this form to provide the active bromine content of the resulting solution. The preferred alkali metal dichlorohypobromite is dichlorohypobromideSodium salt.
A preferred method of forming the above-described aqueous biocide composition comprising water is to mix together in relative proportions the following materials having in solution at least 100000ppm (wt/wt) and from 145000 to 160000ppm (wt/wt), in accordance with the invention in the range of above 160000ppm (wt/wt) to 215000ppm (wt/wt) active bromine content, the materials being (i) bromine chloride, or a combination of bromine chloride and bromine, and (ii) an overbased aqueous solution of alkali metal sulfamates, or (iii) water, alkali metal base and alkali metal sulfamates, or (iv) water, base and sulfamic acid, or any combination of (v) (ii), (iii) and (iv), and the alkali metal relative proportions being such that the atomic ratio of nitrogen to active bromine in the biocide composition is greater than 0.93, preferably greater than 1, the pH of the biocide composition is at least 7 (e.g. in the range of 10 to 13.5), and preferably in the range of 12 or 12.5 to 13.5 or 14.
In each embodiment of the present invention, the atomic ratio of nitrogen to active bromine is preferably in the range of 1.1 to 1.5, more preferably in the range of 1.35 to 1.5. Higher ratios may also be used if desired.
As noted above, amounts of active bromine above 160000ppm (wt/wt) are within the scope of the present invention. In other words, any stable active bromine component concentration in excess of 160000ppm (wt/wt) that does not result in the formation of a precipitate during storage or transport of the concentrated solution under normal ambient temperature conditions (e.g., 23 ℃) constitutes a composition of the present invention. When used for microbial control, the concentrated solutions of the present invention are mixed or diluted with or introduced into additional water, typically the water that needs to be treated for such microbial control, so that the amount of active bromine in the water treated for microbial control is a microbiologically effective amount. The various compositions of the embodiments mentioned in this paragraph preferably also contain dissolved chloride ions, most preferably a stoichiometric excess of alkali metal cations such as sodium or potassium cations is present. The alkali metal chloride salts have a high solubility in the aqueous medium of the concentrates according to the invention compared with certain other alkali metal salts and therefore do not cause any problems with respect to precipitate formation during storage, transport or use. In addition, the dissolved alkali metal chloride in the solution of the present invention minimizes the extent to which oxygen or air dissolves in the concentrated solution.
Although not mandatory, it is preferred that the compositions of the present invention remain peroxide-free from the beginning of their production.
Still other embodiments of the invention include the following:
1) containing sulfamate-stabilized bromineAn ionic, concentrated aqueous biocide composition which (i) has a pH of more than 8 from its start, and (ii) is Br2Measured, more than 16 wt% bromine was present in the solutionIonic, such wt% based on the total weight of the composition.
2) The concentrated biocide composition of claim 1), wherein from its very beginning the composition has a pH of greater than 10.
3) Comprises passing through BrCl andSO3NH2concentrated aqueous, reaction-stable oxyhalogen biocide compositions which are (i) Br2Measured as having greater than 16 wt% bromine in solutionIons, such wt% based on the total weight of the composition, and (ii) having a pH of greater than 10.
4) Comprises passing through BrCl andSO3NH2concentrated aqueous biocide composition of stabilized oxyhalogen obtained by reaction with Br2Measurement of, such asThe composition comprises at least 16 wt% bromine in solutionIonic, such wt% based on the total weight of the composition.
Preferably, but not necessarily, the compositions of 1), 2), 3) and 4) above are further characterized by comprising chloride ions in solution thereof.
Preferred alkali metal salts of sulfamic acid and preferred alkali metal bases used to form such salts are potassium sulfamate and potassium bases such as KOH, respectively. Most preferred are sodium sulfamate and sodium base such as NaOH, respectively.
One desirable method of achieving reactant mixing in the production of the concentrated liquid biocide formulations of the invention comprises simultaneously introducing into a reaction zone, such as a reactor or other reaction vessel, an aqueous solution of (a) bromine chloride and (b) an alkali metal salt of sulfamic acid, the resulting solution having a pH of at least 7 (e.g., in the range of 10-13.5), and preferably in the range of 12 or 12.5 to 13.5 or 14. As mentioned above, the proportions of (a) and (b) used are such that (i) the active bromine content in the solution is at least 100000ppm (wt/wt), for example from 145000 to 160000ppm (wt/wt), in accordance with the invention in the range of above 160000ppm (wt/wt) to 215000ppm (wt/wt), and (ii) the atomic ratio of nitrogen from (a) and (b) to active bromine is greater than 0.93, preferably greater than 1.
The addition of a biocidal effective amount of active bromine as a composition of the present invention to water treated in accordance with the present invention results in substantial dilution because bromine (as Br) is typically present in the range of 0.5 to 20ppm in the treated water in the aqueous medium treated for biocidal and/or biofilm control on a wt/wt basis2Expressed as Br) and preferably in the range of from 4 to 10ppm of bromine (expressed as Br)2Expressed) is generally sufficient. This results in efficient microbial control in the treated water.
A further advantage of the present invention is that the concentrated aqueous biocide compositions of the present invention are produced without the need to use strong oxidizers such as ozone or peroxides, which are considered to have undesirable and actually harmful characteristics.
The following additional examples are provided for illustration and not limitation.
Examples 11 to 17
Various compositions were prepared using the general procedure described above and the resulting compositions were assayed for active bromine content. The conditions used and the results obtained (observations of odor and vapors, and initial content of active bromine in solution) are summarized in Table 6, where SAeqRepresenting the molar ratio of sulfamic acid to halogen.
Table 6 data on the sulfamic acid stabilized bromine solutions prepared
| Example numbering | Halogen | pH | SAeq | Description of smell and vapor | Active bromine (wt%) |
| 11 | Br2 | 13.0 | 1.42 | Slightly sweet, no steam observed | 12.4％* |
| 12 | Br2 | 7.0 | 1.48 | Slight Br smell, no fuming | 13.4％* |
| 13** | BrCl | 7 | 0.92 | Strong Br smell, slight fuming | 11.2％ |
| 14 | Br2 | 13.0 | 1.15 | Slightly sweet, no steam observed | 19.6％ |
| 15 | Br2 | 7.0 | 1.13 | Moderate Br flavor and no fuming | 26.7％ |
| 16 | BrCl | 12.5 | 0.94 | Slightly sweet, no steam observed | 18.0％ |
| 17 | BrCl | 2.8 | 0.41 | Slightly sweet, no steam observed | 17.6％ |
*Measured with a Hach spectrometer; all others were titrated using the starch-iodine-sodium arsenite method.
**Comparative example.
Specific details of examples 13-17 of Table 6 are given below. Example 19 illustrates the use of alkali metal dichlorohypobromite as the active bromine source.
Example 13
Bromine chloride, caustic and sodium sulfamate of neutral pH
A1 liter flask was charged with 52.0g sulfamic acid and 250g water. Sodium sulfamate was prepared by adding 60.0g of 50% sodium hydroxide to the stirred slurry. Bromine chloride was prepared by adding 20g of chlorine to 47.0g of bromine. The bromine chloride was then added with 210g of 25% sodium hydroxide to maintain the pH between 6 and 8. 5mL of 1M hydrochloric acid was added to bring the final pH to about 7. + -. 0.5. The solution containing some solids was transferred to an amber bottle for storage. A sample of the starch-iodine titration solution showed it to have an active bromine concentration of 11.2%.
Example 14
Bromine, caustic (50% sodium hydroxide) and sodium sulfamate
A500 mL flask was charged with 26.0g of sulfamic acid and 50g of water. To the slurry was added 35.0g of 50% sodium hydroxide. Since the acid is converted to the sodium salt, it can be more easily dissolved into an aqueous solution. Bromine (37.0g) and 50% sodium hydroxide (30.0g) were added together to the solution at a rate to maintain the pH between 11 and 13. After all bromine and caustic were added, the contents were transferred to an amber bottle for storage. A sample of the starch-iodine titration solution showed it to have an active bromine concentration of 19.6%. Bromine solutions were analyzed, which also contained over 95% active bromine content.
Example 15
Bromine, caustic and neutral pH sodium sulfamates
A500 mL flask was charged with 26.0g of sulfamic acid and 50g of water. To this stirred slurry was added 30.9g of 50% sodium hydroxide, which raised the initial pH to about 12. Sulfamic acid was then dissolved into the solution. Bromine (37.7g) was added to the solution until the pH dropped to about 7, at which time 50% sodium hydroxide (10.9g) was co-added to maintain the pH between 6 and 9. The final pH was brought to about 7. + -. 0.5 using 5mL of 0.01N sodium hydroxide. The contents were then transferred to an amber bottle for storage. Starch-iodine titration of a sample of the solution indicated it to have an active bromine content of 26.7%. Analysis of the solution after 6 weeks of storage at ambient temperature showed that the stabilized bromine solution still contained over 95% active bromine content.
Example 16
Bromine chloride, caustic and sodium sulfamate
A1 liter flask was charged with 107g sulfamic acid and 200g water. Sodium sulfamate was prepared by adding 93.9g of 50% sodium hydroxide to the stirred slurry. Bromine chloride was prepared by adding 39g of chlorine to 96.0g of bromine. The bromine chloride was then co-added with 319g of 50% sodium hydroxide to maintain the pH between 11 and 13. After stirring for an additional 30 minutes, the solution containing some solids was transferred to an amber bottle for storage. A sample of the starch-iodine titration solution showed it to have an active bromine concentration of 18.0%. Analysis of the solution after 3 weeks storage at ambient temperature showed that the stabilized bromine solution still contained over 90% active bromine content.
Example 17
Bromine chloride, caustic and sodium sulfamate; large scale of production
A5 liter flask was charged with 470g sulfamic acid and 900g water. Sodium sulfamate was prepared by adding 436g of 50% sodium hydroxide to the stirred slurry. Bromine chloride was prepared by adding 120g of chlorine to 276g of bromine. This bromine chloride was then added with 1723g of 50% sodium hydroxide to maintain the pH between 12 and 13. After stirring for another 60 minutes, the orange clear solution was transferred to a polyethylene bottle for storage. A sample of the starch-iodine titration solution showed it to have an active bromine concentration of 17.6%.
Example 18
Bromine chloride, caustic and sodium sulfamate; large scale of production
A5 liter flask was charged with 390g sulfamic acid and 400g water. Sodium sulfamate was prepared by adding 1820g of 25% sodium hydroxide to the stirred slurry while cooling to keep the temperature below 30 ℃. 344g of bromine chloride are then added. The orange clear solution had a pH of 13.5, was filtered and transferred to a polyethylene bottle for storage. A sample of the starch-iodine titration solution showed it to have an active bromine concentration of 16.2%.
Example 19
Reduction of vapour pressure of sodium dichlorobromite with sodium sulfamate
Sodium sulfamate was prepared by slurrying 24.3g of sulfamic acid in 9g of water. 24.0g of 50% sodium hydroxide are added dropwise. The flask was heated significantly and the solids dissolved. The solution was added dropwise to 184.6g of sodium dichlorohypobromite. Preparation of sodium dichlorobromite Na [ BrCl ] by adding 30.6g of bromine chloride to 154g of 3M aqueous sodium chloride solution2]. An additional 24g of 50% sodium hydroxide was added to raise the pH to 7. Analysis of the solution showed it to have an active bromine concentration of 12.0%.
Presently, the preferred method of carrying out the process of the invention on a large scale involves charging a reactor with water, an aqueous alkali metal hydroxide solution (preferably aqueous sodium hydroxide), sulfamic acid, followed by bromine chloride, or a mixture of bromine chloride and bromine. The preferred proportions of the components are, based on 100 parts by weight in total, 17 parts by weight of water, 59 parts by weight of 25% by weight aqueous sodium hydroxide solution, 13 parts by weight of sulfamic acid and 11 parts by weight of bromine chloride. The components are preferably charged in the order listed. However, the order of addition of the other three components may be varied so long as bromine chloride is added last. The bromine chloride used preferably contains 68.9 to 73.1% by weight of bromine. However, if desired, pure bromine chloride, or other combinations of bromine chloride and bromine, can be used to prepare useful products. The temperature of the mixture during the bromine chloride addition preferably does not exceed 50 c, although the temperature may be allowed to exceed 50 c for short periods of time without detrimental effects. Prolonged exposure to high temperatures tends to result in degradation of the product and should therefore be avoided. The bromine chloride concentration in the resulting product solution formed in this manner (regardless of the chemical form in which the active bromine chloride is present in such solution) is in the range of above 16.0 wt% to 21.5 wt% (e.g., between 165000ppm and 215000ppm (wt/wt)), and preferably targets an active bromine content in the range of 17.6 wt% to 19.0 wt% (i.e., in the range of 176000ppm wt/wt to 196000 ppmwt) or an active bromine content in the range of 20.1 wt% to 21.5 wt% (i.e., in the range of 201000ppm wt/wt to 215000ppm wt/wt). Determination of such concentrations can, of course, be readily accomplished by starch-iodine titration. When operating as described in this paragraph, the final pH of the product solution is in the range of 12.4-13.7. It is to be understood and appreciated that in accordance with the present invention, equivalent amounts of bromine, or bromine and chlorine instead of bromine chloride, or a mixture of bromine chloride and bromine may be used in this process.
Another preferred method of large scale operation of the process described immediately in the preceding paragraph is in a semi-continuous or semi-batch mode. This involves forming an alkali metal sulfamate solution, preferably a sodium sulfamate solution (using caustic, water, sulfamic acid), and feeding bromine chloride, or bromine chloride and bromine (BrCl), into a suitable vessel (reactor or tank) containing the sulfamate solution. The BrCl may be passed directly into the vessel of the aqueous solution of sodium sulfamate or into the pumping system loop of the vessel. BrCl can be prepared in advance or by continuously mixing together bromine and chlorine in a tube, with or without a mixing element, and then directly injected into the aqueous sodium sulfamate solution without isolating BrCl. The advantage of continuous preparation of BrCl is that it avoids having a separate BrCl reactor or storage tank and avoids the need to store large quantities of this material on the equipment set up.
In addition to use in microbial treatment of aqueous media such as recreational water, industrial cooling water, process water and wastewater, the concentrated solutions of the present invention can also be used to eradicate or at least reduce biofilm on surfaces in contact with aqueous media, such as cooling tower surfaces, filter surfaces, surfaces in pools and spas, the interior surfaces of pipes and tubing, and similar surfaces on which biofilm can form. In addition to surface damage and/or unsightliness that causes the bacterial film to adhere firmly, biofilms can harbor dangerous pathogens. And biofilms can interfere with normal water flow as they can form a slime layer. Despite the fact that the adhesive film itself constitutes a barrier to biocide penetration, the biocide solution of the present invention makes possible effective biocidal control of biofilms. Thus, in accordance with the present invention, the concentrated aqueous solutions of the present invention can be used to introduce a biocidally effective amount of active bromine into an aqueous system in contact with a surface infested by a significant amount of biofilm, thereby at least reducing, if not completely eradicating, the biofilm. This is, of course, accomplished by adding to the water to be treated to reduce or eradicate the biofilm an amount of the concentrated aqueous solution of the present invention at least as much as, if not all, to reduce the biofilm. Generally, the amount of active bromine (as Br) in the aqueous medium treated to control biofilm is in the range of 0.5 to 20ppm2Expressed as Br) and preferably an amount of active bromine in the range of 4-10ppm2Indicated), is generally sufficient, but smaller or larger amounts of active bromine may be used, as deemed necessary, suitable, or desirable. Of course, a period of time may elapse between the time the concentrated aqueous solution of the present invention is brought into contact with the water to be treated and thereby diluted and the time the biofilm is reduced or eradicated. If desired, such reduction or eradication can be observed by periodic visual inspection of the water-contacting surface infested by significant biofilm growth,it is assumed that such a surface is in a position that can be observed by a person. In the case of filters, pipes or tubes which are infested with significant biofilm and which transport water treated in accordance with the invention by treating the water with a biocidal amount (amount) of the concentrated aqueous solution of the invention to reduce or eradicate such biofilm, reduction or eradication of biofilm may be evidenced and thus observed by improved performance of the device (e.g., increased water flow). However, regardless of whether such observation is made, biofilm reduction or eradication occurs when a suitable amount of the concentrated solution of the present invention is added to water in contact with the biofilm to include a biocidally effective amount of active bromine in such water.
The solid biocide compositions of the invention are also used in amounts sufficient to be effective in controlling microorganisms, biofilms, and/or other pathogens to be controlled. Thus, in an aqueous medium treated to control biofilm, it is possible to produce a composition containing, for example, 0.5-20ppm of active bromine (as Br)2Expressed as Br) and preferably from 4 to 10ppm of active bromine (expressed as Br)2Expressed) is generally sufficient, but smaller or larger amounts of active bromine may be used again, as deemed necessary, appropriate or desirable. One preferred application of the solid product of the invention is in the control of bacteria and other microorganisms present in subterranean zones, such as in the pores being drilled or used in oil and/or gas fields. To this end, the present invention provides a water-soluble or water-disintegrable container or bag which contains a suitable microbicidal amount of the solid biocide or composition of the invention. Such a package consisting of a container or bag of the solid biocide of the invention can simply be dropped into the hole. When the water level in the well is reached, the biocide of the invention quickly dissolves into the water and thus provides a powerful microbicidal effect on microorganisms present in the well being drilled or used, including various anaerobic species and sessile bacteria. The amount of solid biocide contained in the package will depend on factors such as the size of the pores and the degree of microbial activity to be controlled. Thus, in any given case, the amount of biocide used in the package can be readily determined by performing several trial productions. The solid biocides of the present invention have the advantage thatIn that they can be effectively used in amounts well in excess of the amounts actually required to achieve biocidal activity without encountering significant adverse results. Therefore, precise control of the amount used in a given downhole process is generally not required.
Even though the claims hereinafter may refer to substances, components and/or ingredients in the present tense ("comprises" or "is"), the reference to a substance, component or ingredient is to the substance, component or ingredient as if it were present immediately prior to first contacting, blending or mixing with one or more other substances, components and/or ingredients, or if formed in solution, as if it were not formed in solution, and is fully consistent with the present invention. It is not critical that the substance, component or ingredient lose its original identity through a chemical reaction or transformation during such contacting, blending, mixing or in situ formation, so long as it is performed in accordance with the present invention.
Claims (2)
1. A method of providing an aqueous biocide composition having high storage stability and substantially the same or better crystallization temperature when compared to a composition made with the same components having a lower active bromine level, the method comprising:
providing an aqueous biocide composition having in solution: an active bromine content from (i) bromine chloride, or bromine chloride and bromine, said active bromine content being 201000 and 215000ppm by weight; and (ii) an overbased alkali metal salt of sulfamic acid, wherein the relative proportions of (i) and (ii) are such that the atomic ratio of nitrogen to active bromine from (i) and (ii) is greater than 0.93, and wherein the pH of the composition is at least 7.
2. An aqueous biocide composition prepared according to the process of claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US10/282,290 US8414932B2 (en) | 1998-06-01 | 2002-10-28 | Active bromine containing biocidal compositions and their preparation |
| US10/282,290 | 2002-10-28 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| HK1124485A1 HK1124485A1 (en) | 2009-07-17 |
| HK1124485B true HK1124485B (en) | 2014-01-30 |
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