BACKGROUND OF THE INVENTION

Field of the Invention The present invention relates to compositions including organic am onium perhalides and a bromine stable, organic solvent, and which are characterized by a low bromine vapor pressure. The compositions are stable and possess high concentrations of easily available oxidizing bromine, and have utility as water sterilization agents.

Description of the Prior Art

The preparation and utility of ammonium perhalides as are useful in the present invention are described in U.S. Patent No. 4,886,915, issued to Favstritsky on December 12, 1989. These compounds have been found to be particularly desirable in view of their stability, water solubility and high concentrations of easily available oxidizing bromine.

The perbromide ion (Br_ ) in solution is in equilibrium with bromide ion (Br ^~ ) and bromine (Br_). The perbromide ion has no measurable vapor pressure, while dissolved bromine (Br-) will give a distinct bromine odor. It is desirable that compositions containing the ammonium perhalides have a low bromine vapor pressure. U.S. Patent No. 4,898,975, issued to Favstritsky on February 6, 1990, describes formulations which use the addition of organic and inorganic halide salts to reduce bromine vapor pressure through a common ion effect. The additional halide, especially bromide, serves to inhibit perbromide dissociation to bromide ion and bromine. The foregoing organic ammonium compositions, optionally

including halide salts to reduce bromine vapor pressure, have been shown to be useful for controlling biofouling in recirculating water systems. Such use may occur in water cooling Lowers, air conditioning systems and the like, and is described in U.S. Patent No. 4,935,153, issued to Favstritsky et al. on June 19, 1990, and U.S. Patent No. 4,966,716, issued to Favstritsky et al. on October 30, 1990.

Bromine compositions of the aforedescribed type will desirably have low vapor pressure while having a high bromine content. It has surprisingly been discovered that reduction of bromine vapor pressure is obtained by adding a water soluble, bromine stable, organic solvent to an organic perbromide formulation.

The use of organic solvents as stabilizing mediums for hydrogen perbromide and sodium perbromide has been identified in the prior art. For example, it has been reported that the equilibrium constant for the interaction:

K = (Br ₃ )/(Br ^" )(Br ₂ )

increases with the volume percent of acetic acid in aqueous solution. This evaluation was performed to quantitatively interpret the inhibition of aromatic bromination reactions by bromide ion in acetic acid and in aqueous acetic acid solutions, due to tribromide formation. See T.W. Nakagawa, L.J. Andrews, R.M. Keefer, J.Phys. Chem..£, pp. 1007-1009 (1957) . Similar observations as to inorganic perbromide stability in methanol are set forth in J.E. Dubois, F. Gamier, Bull. Soc. Chim. Fr., pp. 1715-1718 (1965).

There remains a need for cost effective, low bromine vapor pressure bromine carriers with good water dispersibility. However, the reduction of bromine vapor pressure for organic perbromides by the addition of a water soluble, bromine stable, organic solvent has not been previously recognized.

SUMMΛRY OF THE INVENTION

The present invention is directed to organic perbromide compositions including (1) water soluble mono- and disubstituted ammonium perhalide compounds of the formula R,R„NH ₂ XBr where R, and R_ are independently hydrogen or organic substituents, with only one of R, and R_ being hydrogen; X is chlorine, bromine or iodine; and n is 2 to 6; and (2) a bromine stable, organic solvent. More particularly, the compounds of the present invention include compounds in which the organic substituents for R. and R„ may include hydrogen, hydroxyethyl, alkyl, cycloalkyl, (alpha, omega)-alkyl, alkyl ether, polyether, heterocyclic ring-substituted alkyl, polyoxyalk lene, and halogenated alkyl. These mono- and disubstituted ammonium perhalides possess high concentrations of oxidizable bromine, are stable, have good water solubility and can be easily prepared. The organic solvents are selected to be stable with the perhalides and to provide reduced bromine vapor pressure. It is an objective of the present invention to provide a cost effective composition of organic perbrornides having a high bromine content and a low bromine vapor pressure.

A further object of the present invention is to provide an organic perhalide composition having good water dispersibility, and being useful for controlling biofouling in recirculating water systems.

Further objects and advantages will be apparent from the description of the preferred embodiment which follows.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the preferred embodiment of the invention and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations, modifications and further applications of the principles of the invention being contemplated as would normally occur to one skilled in the art to which the invention relates.

The present invention provides useful organic perhalide compositions which are characterized by significantly reduced bromine vapor pressures. It has been discovered that the addition of a bromine stable, water soluble, organic solvent to the organic perhalide compound, with or without the further addition of water, will reduce the bromine vapor pressure while providing a cost effective and readily water dispersed product. In fact, the present invention reduces the vapor pressure of the perhalide composition by as much as an order of magnitude, while keeping the bromine content at least as much as 10% by weight.

The resulting perhalide compositions are useful in the same manner as the perhalide compositions disclosed in the Favstritsky et al. patents cited in the "Description of the Prior Art", the pertinent portions of which are hereby incorporated by reference. In addition, the use of suitable organic solvents can eliminate the need for the use of additional halide salts, and also is inexpensive and environmentally acceptable. In accordance with the present invention, mono- and disubstituted ammonium perhalides are combined with organic solvents, with the result being a reduction in the bromine vapor pressure of the composition. A favorable shift in the equilibrium toward the perbromide ion apparently results from

the lower dielectric strength of the organic medium, as suggested by the following relationship:

Br ^~ + Br _? *» Br_ high dielectric low dielectric medium medium

The compositions therefore maintain a high bromine content, but provide cost effective, low bromine vapor pressure bromine carriers with good water dispersibility.

The present invention involves the combination of bromine stable, organic solvents with the perhalides. The prior art indicates that it may be convenient to blend the perhalide compounds used in this invention with water to produce a liquid mixture which can easily be handled by pumping and metering devices. However, while water is the preferred diluent for making formulations with excellent shelf life, there are instances where it is desirable to make formulations with very low bromine partial vapor pressures. In these instances, water soluble, bromine stable solvents alone or in combination with water produce the desired liquid formulations.

Solvents which may be used in this fashion include aliphatic nitro, nitrile and carboxylic acids, some alcohols and some amides. While considerations such as cost, toxicity, and shelf life will affect the decision as to which solvent to choose, suitable solvents will include one or more of the following solvents: nitrometha e, acetonitrile, acetic acid, propionic acid, tertiary butanol, methanol, N,N-dimethyl acetamide and N-methyl pyrrolidinone. From this group of organic solvents, acetic acid and methanol, which are inexpensive and environmentally safe, are especially preferred.

The water soluble mono- and disubstituted ammonium

perhalides useful in this invention are compounds of the following structure:

where R, and R_ are independently hydrogen, hydroxyethyl, alkyl, cycloalkyl, (alpha, omega)-alkyl, alkyl ether, polyether, heterocyclic ring-substituted alkyl, polyox alk lene, and halogenated alkyl, at most one of R, and R_ being hydrogen; X is chlorine, bromine or iodine; and n is 2 to 6. As known in the art, these perhalide compounds may be prepared by reacting the corresponding raono- or disubstituted ammonium hydrohalide salt with bromine. The solubility and bromine content of the perhalide compounds depend on the bulk and nature of the substituents. The most preferred substituents are R, = hydroxyethyl or C 1, to CO_ alkyl groups, and R A_ = hydrogen, hydroxyethyl, or C, to C„ o alkyl groups.

In general, the compounds of this invention include mono- and disubstituted perhalides where X may be bromine, chlorine or iodine. It is preferred, however, to employ compounds where X is bromine, i.e., perbroπiides of the formula

^R l ^R 2 ^NH 2 ^Br n ₊ l' ^{SUCh aS R} l ^R 2 ^NH 2 ^Br 3-

Specific stable, water soluble perhalides useful with the present invention include ethanolammonium perbromide, propylammonium perbromide, diethanolammonium perbromide, butylammonium perbromide, methylethanolammonium perbromide, ethylethanolammυnlum perbromide, hexylammonium perbromide octylammonium perbromide, dipropylammonium perbromide, dibutylammonium perbromide, diethylammonium perbromide, and 1,6-hexanediammonium perbromide, as well as the corresponding chloro and iodo-dibromides.

If desired, the shelf life of aqueous solutions of the compounds of this invention may be stabilized by increasing the amount of ammonium hydrohalide in relation to bromine. More particularly, up to four moles of mono- or disubstituted ammonium hydrohalide salt may be admixed with one mole of bromine. Perhalides with lower apparent vapor pressure and lower oxidizable bromine content are produced when two moles of salt in aqueous solution are added to one mole of elemental bromine. Mono- and disubstituted ammonium hydrohalide salts which may be used include those of the formula:

*2

where R,, R„ and X are as previously defined.

Shelf life stability may also be increased by replacing part of the substituted ammonium hydrohalide salt with other stability enhancing salts such as alkali metal and ammonium bromides, especially a monium bromide and sodium bromide, preferably in a molar ratio of about 1:1. Preferably, the substituted ammonium hydrohalide salt and other stability enhancing salt, if any, are provided in a ratio lying in the range of about 1 to 4 moles of salt to 1 mole of bromine.

The compositions of this invention can be easily prepared by mixing the organic solvent with perhalide compounds formed by various known processes as exemplified by the following. For example, the perbromides may be prepared by first reacting the corresponding amines with hydrogen halide (Equation 1), followed by the addition of bromine (Equation 2):

R^NH + HX s* RχR ₂ NH2X (1)

R-LR ₂ H ₂ X + Br ₂ s> R ₁ R ₂ NH ₂ XBr ₂ (2)

Alternatively, anhydrous perbromides can be easily prepared by gently heating the dry amine hydrobromide salt with bromine.

Conveniently, an aqueous solution of lower alkyl- or dialkyl-ammonium perbromides can be prepared by reacting the readily available and inexpensive aqueous 48% hydrobromic acid with neat amine. The resulting aqueous amine hydrobromic salt is then readily converted to the perbromide by the addition of bromine. A simple one-pot procedure produces aqueous solutions of perbromides with exceedingly high bromine content. The organic solvent is then added thereto.

Another method of preparing the perhalide compounds consists of first dissolving the bromine in hydrobromic acid (Equation 3), followed by the addition of the neat amine (Equation 4) :

HBr + Br ₂ - ^~ - HBr ₃ (3)

HBr ₃ + R!R ₂ NH 5» R!R ₂ NH ₂ XBr ₂ (4)

Still another method for the preparation of the perhalide compounds used in the present invention, especially if higher bromine content in the final solution is desired, consists of reacting a more concentrated hydrobromic acid with amine, followed by bromine addition. Alternatively, the corresponding aqueous solution of the amine hydrobromide can be concentrated by evaporating water, followed by the addition of an appropriate amount of bromine.

Analogous procedures may be employed to produce the chlorine and iodine containing perhalides useful in this invention by employing the corresponding hydrogen halide in the foregoing reactions.

The perhalides used in this invention may also include those containing additional bromine. The bromine content of

these perhalides may be increased by adding more than one mole of bromine to the substituted-ammonium hydrobromide, yielding a higher perbrominated salt, as illustrated by Equation (5) .

R ₁ R ₂ NH ₂ Br + 2Br ₂ R!R2 H ₂ B 5 (5)

Although four or more moles of bromine can be added to the aqueous amine hydrobromide, the solution, upon contact with excess water, releases elemental bromine. However, it is possible to prepare solutions of perbromides in which the bromine content approaches R.R.NH Br and which does not release bromine upon contact with excess water.

The inventive solutions of perhalides have good shelf life stability. Generally, in aqueous solution onoalkylammonium perbromides are more stable than dialkylammonium perbromides. Furthermore, the more dilute the perbromide solution, the lower its stability unless stabilized with additional stabilizer additives.

The perhalide compositions of this invention, though high in bromine content, show surprisingly low vapor pressure of bromine. Liquid elemental bromine has a vapor pressure of approximately 220 mm Hg at 26°C and bromine water (containing approximately 3.5% by weight of bromine) shows a vapor pressure of 210 mm Hg at 26°C. For comparison, aqueous NaBr_ containing roughly 40% Br_ has a bromine partial vapor pressure of about 80 mm Hg. Aqueous solutions of organic perhalides such as described by Favstritsky in U.S. Patent No. 4,886,915 further reduce this bromine partial vapor pressure to less than 20 mm Hg at roughly the same bromine content (these numbers differ from Favstritsky because total vapor pressure is not being measured) .

Finally, in accordance with this invention the dilution of these organic perhalides with bromine stable solvents and/or stabilizer salts reduces the bromine partial vapor pressure

to less than half that of the undiluted organic perhalides. This is important for containment, corrosion minimization and reduction of personnel exposure during shipment, storage, and application. The following examples will detail the preparation, properties and stability of the preferred perbromide/solvent compositions in accordance with the present invention.

EXAMPLE 1 Preparation of Ammonium Perbromides

In a 5.01, four-necked round-bottom flask, immersed in an ice bath and equipped with a mechanical stirrer, reflux condenser, addition funnel, and thermometer, HBr (48%) (1940 g, 11.5 moles) was placed. Ethanolamine (703 g, 11.5 moles) was slowly added at a rate such that the temperature did not exceed 50°C, to ensure minimal loss of HBr.

After the addition of the ethanolamine was completed, the reaction mixture (61.8% ethanolamine hydrobromide) was allowed to cool to room temperature. Then, bromine (1840 g, 11.5 moles) was carefully added via the addition funnel, and the temperature was maintained below 50°C. The yield of the dark red aqueous ethanolammonium perbromide (Compound #1) was 4483 g.

The perbromide was then titrated for oxidizable bromine via the method described in "Standard Methods for the Examination of Water and Waste Water," 15th edition: Method 408A. Data for Compound #1 is given in Table 1.

Other water soluble organic ammonium perbromides identified as Compounds #2-9 in Table 1 were prepared via the procedure used for Compound #1, but on a reduced scale. Data for these compounds is also reported in Table 1.

TABLE 1 COMPLETELY SOLUBLE PERBROMIDES PREPARED FROM AQUEOUS SOLUTION pound

Name Structure

1 Ethanolammonium Perbromide HOCH-CH NH-Br.,

2 Butylammonium Perbromide

^CH 3 ^(CH 2 3 ^NH 3 ^Br 3

3 Propylammonium Perbromide CH ₃ (CH _{2 2} NH3Br ₃

4 Piethanolammonium Perbromide (H0CH ₂ CH ₂ ) ₂ H ₂ Br ₃

5 Methylethanolammonium Perbromide CH ₃ ) (HOCH ₂ CH2 NH ₂ Br3

6 Ethylethanolammonium Perbromide CH ₃ CH ₂ )(H0CH ₂ CH ₂ )NB- ₂ Br ₃

7 Dimethylethanolammonium (CH ₃ ) ₂ (HOCH ₂ CH ₂ )NHBr ₃ Perbromide

8 Hexylammonium Perbromide CH ₃ CH ₂ ) ₅ NH ₃ Br ₃

9 Octylammonium Perbromide CH ₃ (CH2 ₇ H ₃ Br3

- Oxidizable bromine calculated on an aqueous mass balance. ** Theoretical oxidizable bromine content of the neat compound,

t~. ^~~ >

~~t t~>

I

A series of additional perbromides identified as Compounds #10-14 were prepared using the procedure described above. However, after the addition of the bromine was completed, two liquid phases were produced. The top phase was an aqueous layer and contained a minimal amount of bromine. The bottom phase, a viscous liquid, represented the perbromide, which in most instances contained oxidizable bromine very close to the theoretical oxidizable bromine content of the neat compound. Data for Compounds #10-14 is given in Table 2.

TABLE 2

PARTIALLY SOLUBLE PER ROMIDES PREPARED FROM AQUEOUS SOLUTION

Com¬ pound Tit. Ox. Br ₂ Theo. Ox. Br ₂ ** Solubility

# Name Structure by Weight % by Weight (g/100 g H ₂

10 Dipropyla-mmonium (CH ₃ (CH ₂ ) ₂ ) ₂ H ₂ Br ₃ 45.1 46.7 10 Perbromide

11 Dibutylammoniu-ra (CH ₃ (CH ₂ ) ₃ ) ₂ NB ₂ Br ₃ 40.9 43.3 1.0 Perbromide

12 Tributyla-mmoniu-m (CH ₃ (CH ₂ ) ₃ ) ₃ HBr ₃ 36.0 37.5 0.01 Perbromide

13 Triethyl mmonium (CH CH ) NHBr 45.6 46.7 0.1 Perbromide

14 Diethylethanola-mmonium (CH ₃ CH ₂ ) ₂ (H0CH ₂ CH ₂ )NHBr ₃ 42.3 44.7 0.1

** Theoretical oxidizable bromine content of the neat compound,

Compounds #15 and #16 were prepared using the foregoing procedure. The perbromides produced were crystalline solids which precipitated as the bromine addition proceeded. Data for Compounds #15 and #16 is shown in Table 3.

TABLE 3

PERBROMIDES WHICH PRECIPITATED OUT OF AQUEOUS SOLUTION

Com¬ pound Tit. Ox. Br2 Theo. Ox. Br2** Solubility # Name Structure 7. by Weight 7. by Weight (g/100 g H ₂ 0)

15 Diethylammonium (CH ₃ CH ₂ ) ₂ NH ₂ Br ₃ 47.9 50.9 15 Perbromide

16 1,6-Hexanediammonium Br ₃ H ₃ N(CH ₂ ),NH ₃ Br ₃ 51.8 53.5 50

Perbromide

Theoretical oxidizable bromine content of the neat compound.

Compounds #7, #12, #13, #14, which are all trisubstituted amine hydroperbromides, were used for comparison purposes. All except Compound #7 are only sparingly soluble in water, and thus are unsuitable for use where high water solubility is required. The water solubilities of the perbromides which separated from the solution are shown in Tables 2 and 3. Again, with the exception of Compound #7, they are all significantly more soluble than the trisubstituted ammonium hydrotribromides.

EXAMPLE 2

Concentrated Organic Ammonium Perbromides

By concentrating the salt solution used, aqueous perbromides are obtained with higher oxidizable bromine concentrations. These concentrated salt solutions may be prepared in two different ways: (1) the aqueous salt solution may be evaporated to the desired concentration; or (2) a more concentrated HBr may be used. The procedure for preparing a perbromide using concentrated HBr (62%) is described below and the compound is listed as Compound #17 in Table 4.

Compound #17: Concentrated Aqueous Ethanolammonium Perbromide

Using the setup described in the preparation of Compound #1, HBr (62%) (500 g, 3.8 moles) was placed in a round-bottom flask. Ethanolamine (234 g, 3.8 moles) was slowly dripped into the flask. After the neutralization was complete, yielding a 74.1% salt solution, bromine (612 g, 3.8 moles) was carefully dripped into the reaction flask.

T.a-BLE 4 CONCENTRATED AND ANHYDROUS ORGANIC AMMONIUM PERBROMIDES

Com¬ pound Concentration of Tit. Ox. Br2 Calc. Ox. Br2

Name Hydrobromide, 7. 7. by Weight 7- by Weight M.P. CC)

17 Ethanolammonium Perbromide 74.1 47.3 45.5 Liquid

18 Ethanolammonium Perbromide 100 _. 51.8 52.9 47-53

19 Propylammonium Perbromide 100 53.2 53.4 25-29

20 Diethanolammonium Perbromide 100 45.3 46.2 35-45

By using a completely anhydrous amine hydrobromide salt, it was possible to produce solid organic ammonium perbromides. The preparation of Compound #18, shown in Table 4, is described below.

Compound #18: Solid Anhydrous

Ethanolammonium Perbromide

Ethanolammonium bromide (10 g, 0.07 moles), prepared by the neutralization of HBr (48%) by ethanolamine and evaporated to dryness, was placed in a beaker. Bromine (11.2 g, 0.07 moles) was added, and the beaker was covered with parafilm to minimize bromine loss. The beaker was carefully heated to 35°C, at which point the contents of the beaker became a homogenous liquid. The beaker was allowed to sit overnight at room temperature (24°C) . By morning, the perbromide had crystallized.

Two other solid perbromides, solid propylammonium perbromide (Compound #19) and solid diethanolammonium perbromide (Compound #20), were very soluble in water and were prepared in the same manner (see Table 4) .

EXAMPLE 3

Perbromides with lower apparent vapor pressure and lower oxidizable bromine content are produced when two moles of the hydrobromide salt are added to one mole of elemental bromine. If the second mole of salt is the same corresponding amine hydrobromide, then the perbromides are exemplified by Compounds #21-23. The procedure for preparing a 2:1 (salt:bromine) aqueous ethanolammonium perbromide (Compound #21) is described below. However, if the second salt is different, as exemplified by Compounds #24 and #25, then the desired second salt can be added either as a solid or as an aqueous solution, followed by the addition of bromine. The procedure for preparing Compound #24 is given below. Data for Compounds #21-#25 is given in Table 5.

TABLE 5 STABILIZED AQUEOUS ORGANIC AMMONIUM PERBROMIDES

Com¬ pound Tit. Ox. Br2 Calc. Ox. B

Name Stab. Salt Used 7. by Weight 7. by Weight

21 Ethanolammonium Perbromide HOCH ₂ CH ₂ NH ₃ Br 25.4 25.8 22 Propylammonium Perbromide CH ₃ (CH ₂ ) ₂ H ₃ Br 26.9 28.6 23 Piethanolammonium Perbromide (HOCH ₂ CH ₂ ) ₂ NH ₂ Br 20.5 22.6 24 Ethanolammonium Perbromide NaBr 24.4 24.8 25 Ethanolammonium Perbromide NH ₄ Br 23.6 24.8

Cornpound #21: Aqueous 2:1 (Salt:Bromine) Ethanolammonium Perbromide

The ethanolamine hydrobromide salt is prepared via the neutralization of HBr (48%) with ethanolamine as described by Compound #1. Ethanolamine hydrobromide (459.2 g, 2.0 moles) was placed in a 500 ml round-bottom flask, equipped with a mechanical stirrer, thermometer, and addition funnel. Bromine (159.8 g, 1 mole) was slowly added. A dark red liquid (612 g, 98.9% yield based on mass balance) with very low visible vapor pressure was obtained.

Compound #24: Aqueous Ethanolammonium Perbromide Stabilized with NaBr

NaBr (26 g, 0.25 moles) was dissolved in water (38 g) . The resulting solution was added to 100 g of an ethanolammonium perbromide solution containing 0.25 moles ethanolammonium hydrobromide and 0.25 moles of bromine. The perbromide produced had a very low vapor pressure.

EXAMPLE 4

Further addition of bromine to the aqueous organic ammonium perbromides is possible. These perbromides have a higher available oxidizable bromine content and are still soluble in water. Data for these perbromides is listed in

Table 6. The calculated n of the HOCH_CH_NH_BrBr

2 2 3 n molecule is also shown. Compound #29, which had an added bromine concentration of approximately 51%, was the only perbromide that formed pools when a one-ml sample was placed in 200 ml of water.

TABLE 6 HIGHER AQUEOUS ETHANOLAMMONIUM PERBROMIDE

Compound Grams Br ₇ Added Tit. Ox. Br2 Calc. Ox. Br2 to 100 g ^~ Cpd #1 1 by Weight 7. by Weight i ¹ H20 Solubility

26 24.6 52.6 52.5 3.2 Completely 27 46.9 57.7 59.7 4.3 Completely 28 69.0 63.9 65.0 5.5 Completely 29 106.0 72.6 71.3 7.3 Formed pools

^" n calculated for formula ΞOCH ₂ CH ₂ NH ₃ BrBr _n

Perbromide Shelf Life Stability Studies In order to determine the shelf life stability of the perbromide solutions, a series of studies was conducted to determine the percent bromine lost over time. The following tables shown below list the perbromides studied and the percent oxidizable bromine lost over time. The perbromides studied were kept in closed bottles in ambient conditions (Table 7) and at 50°C. (Table 8).

TABLE 7 PERBROMIDE CLOSED-BOTTLE STABILITY AT AMBIENT TEMPERATURE

Compound Initial Ox. Br2 Final Ox. Br2 Relative Change Time Elaps

Name of Perbromide 1 by Weight 7. by Weight Change in 7. Br2 in % Br2 (months)

1 Ethanolammonium 40.1 38.5 1.6 4.0 24

3 Propylammonium 41.3 41.0 0.3 0.7 17

4 Diethylammonium 37.0 35.0 2.0 5.4 24 11 Dibutyla-mmonium 43.2 41.1 2.1 4.9 16

21 Stabilized Ethanolammonium 25.4. 24.9 0.5 2. 24

22 Stabilized Propylammonium 25.6 25.0 0.6 2. 24

23 Stabilized Diethanolammonium 22.1 19.7 2.4 10. 22

30 Diluted Compound #1 20.0 18.0 1.0 5. 24

31 Diluted Compound #3 20.0 18.2 1.8 9. 24

32 Diluted Compound #4 20.0 16.6 3.4 17. 24

TABLE 8 PERBROMIDE CLOSED-BOTTLE STABILITY AT 50' C

Compound Initial Ox. Br2

Name of Perbromide 7. by Weight

1 Ethanolammonium 40.8

3 Propylammonium 41.0

4 Diethylammonium 37.0

21 Stabilized Ethanolammonium 25.8

22 Stabilized Propylammonium 25.6

23 Stabilized Diethanolammonium . 22.5

30 Diluted Compound #1 20.0

31 Diluted Compound §2 20.0

32 Diluted Compound #3 20.0

Vapor Pressure of Perbromides

In accordance with the present invention, useful perbromide formulations are formed by the combination of the foregoing perhalides of Examples 1 and 2 with water soluble, bromine stable, organic solvents. Table #9 illustrates the effect of various exemplary additives and diluents on the bromine partial vapor pressure. The data in Table #9 was determined as follows. 10 milliliters of the formulation were added to a 50 milliliter disposable polypropylene syringe held upright (plunger down) . Then 40 milliliters of air were drawn into the syringe. The syringe was sealed and immersed in a temperature controlled bath at 25°C for two hours to allow equilibration. After equilibration, a capillary PTFE syringe needle was affixed to the syringe and the 40 milliliters of air were carefully displaced into 20 grams of 1.0 N NaOH solution. The bromine content of the air was then titrated using the method described in "Standard Methods for Examination of Water and Waste Water," 15th edition: Method 408A. The partial pressure was then calculated to - 1 torr using the ideal gas law (PV = nRT) .

TABLE 9

VAPOR PRESSURE MEASUREMENTS OF ORGANIC AMMONIUM PERBROMIDE FORMULATIONS

Br2 Partial

Name of Solvent Weight 7. Vapor Pressu or Additive Solvent or Additive (torr at 25°

16

25

34

41

Acetic Acid 26.5 7 Acetic Acid 38.7 4 Acetic Acid 51.0 3 Propionic Acid 51.0 3 Acetonitrile 51.0 <1 t Ethanolammonium 31.8 4 bromide

25.4 28.4 Ethanolammonium 23.5 bromide

Propylammonium 12

30.2 1

49.1 3 49.1 <1 49.1 <1

33 Sodium (NaBr3) 80 35 Pure Bromine 223

The water, perhalide and organic solvent mixtures of this invention can be easily and economically prepared. They are surprisingly stable and have a high concentration of oxidizable bromine. These compositions are useful in many water treatment and other sterilization and disinfection applications where stability and low bromine partial pressure, high bromine content and good water dispersibility are desirable.