Quarternary ammonium halides for treating halogen contamination

Abstract

The invention relates to a method for treating emergency spill or leak of halogen which is bromine or chlorine, comprising contacting an aqueous solution of quaternary ammonium halide with the halogen.

Claims

1. A method for treating emergency spill or leak of halogen which is bromine or chlorine, comprising contacting an aqueous solution of quaternary ammonium halide with the halogen, wherein the quaternary ammonium halide is selected from the group consisting of aliphatic and cyclic quaternary ammonium bromides or chlorides, wherein the aliphatic quaternary ammonium bromide is of the formula R.sub.1R.sub.2R.sub.3R.sub.4N.sup.+Br.sup.−, wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are independently selected from linear or branched C.sub.1-C.sub.5 alkyl, wherein the R.sub.1R.sub.2R.sub.3R.sub.4N.sup.+Br.sup.− is symmetrical quaternary ammonium bromide, such that R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are the same, wherein the quaternary ammonium bromide is tetra ethyl ammonium bromide, tetra propyl ammonium bromide, or tetra butyl ammonium bromide, and wherein the cyclic quaternary ammonium bromide or chloride is selected from the group consisting of 2-methyl-1-alkyl-pyridinium bromides, 2-methyl-1-alkyl-pyridinium chlorides, 3-methyl-1-alkyl-pyridinium bromides and 3-methyl-1-alkyl-pyridinium chlorides wherein the alkyl at position 1 of the ring is linear or branched C.sub.1-C.sub.5 group.

2. The method of claim 1, wherein the 2-methyl-1-alkyl-pyridinium bromide is 2-methyl-1-ethyl pyridinium bromide (2-MEPy) and the 3-methyl-1-alkyl-pyridinium bromide is 3-methyl-1-n-butyl pyridinium bromide (3-MBPy).

3. The method of claim 1, wherein the halogen is bromine.

4. The method of claim 1, wherein the bromine is liquid bromine.

5. The method of claim 4, wherein the aqueous solution of the quaternary ammonium halide comprises a foaming agent, to form a foam on top of the liquid bromine.

6. The method of claim 5, wherein the foaming agent is an aqueous film forming foam (AFFF) agent.

7. The method of claim 5, wherein the quaternary ammonium halide is tetra ethyl ammonium bromide and the foaming agent is an aqueous film forming foam (AFFF) agent.

8. The method of claim 1, wherein the bromine is bromine gas.

9. The method of claim 1, comprising collecting halogen neutralization product as complexed bromine in a form of liquid or solid mass.

10. The method of claim 1, wherein the halogen is chlorine gas, and wherein the aqueous solution of quaternary ammonium bromide further comprises one or more alkali or alkaline earth metal bromides.

11. The method of claim 10, wherein the aqueous solution comprises not less than 40 wt. % of quaternary ammonium bromide and not less than 40 wt. % alkali or alkaline earth metal bromide.

12. The method of claim 11, wherein the aqueous solution comprises: a symmetrical quaternary ammonium bromide of the formula R.sub.1R.sub.2R.sub.3R.sub.4N.sup.+Br.sup.− wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are the same C1-C5 alkyl groups; and sodium bromide or calcium bromide.

13. The method of claim 12, wherein the aqueous solution comprises tetra ethyl ammonium bromide and calcium bromide.

14. The method of claim 11, wherein the aqueous solution comprises tetra ethyl ammonium bromide, tetra propyl ammonium bromide or tetra butyl ammonium bromide.

15. The method of claim 14, wherein the aqueous solution comprises tetra ethyl ammonium bromide.

16. Halogen-neutralizing aqueous solution comprising: from 30 to 60 wt. % tetra alkyl ammonium bromide, wherein the alkyl is linear or branched C.sub.1-C.sub.5 alkyl; and from 30 to 55 wt. % sodium bromide or from 30 to 60 wt. % calcium bromide.

17. The halogen-neutralizing aqueous solution of claim 16, comprising: from 40 to 60 wt. % tetra alkyl ammonium bromide; and from 40 to 55 wt. % sodium bromide or from 40 to 60 wt. % calcium bromide.

18. The halogen-neutralizing aqueous solution of claim 17, comprising: from 40 to 60 wt. % tetra ethyl ammonium bromide; and from 40 to 60 wt. % calcium bromide.

19. The halogen-neutralizing aqueous solution of claim 16, wherein the tetra alkyl ammonium bromide is tetra ethyl ammonium bromide.

20. Use of an aqueous solution of quaternary ammonium halide with concentration of not less than 40 wt. % as halogen neutralization agent in case of emergency leak of the halogen, wherein the halide is bromide, and wherein the aqueous solution of quaternary ammonium bromide further comprises one or more alkali or alkaline earth metal bromides.

21. The use of claim 20, wherein the quaternary ammonium halide is tetra ethyl ammonium bromide, and wherein the alkaline earth metal bromide is calcium bromide.

22. Chlorine neutralization emergency system comprising an aqueous solution of quaternary ammonium halide with concentration of not less than 40 wt. % in an instantly sprayable or pourable form, wherein the halide is bromide, wherein the aqueous solution of quaternary ammonium bromide further comprises one or more alkali or alkaline earth metal bromides.

23. The chlorine neutralization emergency system of claim 22, wherein the quaternary ammonium halide is tetra ethyl ammonium bromide, and wherein the alkaline earth metal bromide is calcium bromide.

Description

SHORT DESCRIPTION OF THE FIGURES

(1) FIG. 1: 1A presents the wt. % change vs. time while 1B presents weight loss magnification of quaternary salts/bromine mixtures.

(2) FIG. 2 depicts a Cl.sub.2 capturing process as described in Example 8A. A is the starting point of the experiment, B is after the addition of 30 gr of chlorine, and D is the resultant phase separation at the end of the experiment.

(3) FIG. 3 depicts a Cl.sub.2 capturing process as described in Example 8B. A is the starting point of the experiment, B is after the addition of 50 gr of chlorine, C is after the addition of 93 gr of chlorine and D is after the addition of 147 gr of chlorine.

(4) FIG. 4 illustrates an experimental set-up used for chlorine neutralization.

EXAMPLES

Example 1

Treatment of Bromine Vapor

(5) Two samples each of 10 gr liquid bromine (Br.sub.2) were added to 250 ml glass bottles. The bottles were sealed, and Br.sub.2 vapor was formed inside the bottles.

(6) 50 wt. % tetra-ethyl ammonium bromide (TEAB) aqueous solution was added to a small spraying flask.

(7) The two sealed Br.sub.2 containing bottles were opened and turned facing down vertically to release the heavy Br.sub.2 vapor. Bottle number (1) was used as a reference, while bottle number (2) was treated as followed: about 3 ml of TEAB solution as described above was sprayed towards the opening of bottle number (2).

(8) Results: reference bottle number (1) continued to release bromine vapor, while no vapor emission was observed from bottle number (2), which was sprayed with the TEAB solution and small brown drops were observed on the interior side of the bottle.

Example 2

Treatment of Bromine Spill

(9) A) 42 gr of 50 wt. % 3-methyl-1-n-butyl pyridinium bromide (3-MBPy; also named BCA13) was added to a separating funnel containing 32 gr of liquid bromine (1:2 molar ratio). The two liquids were mixed via shaking the separating funnel and then kept still. Two phases were immediately formed, a top aqueous phase (slightly yellow) and a bottom organic phase (brown-red). The two phases were immediately collected (separately) and were analyzed utilizing HPLC and titration as follows:

(10) Both phases were analyzed for Br.sub.2 and 3-MBPy using iodometric titration (in which iodide oxidation was followed by titration with thiosulfate) and HPLC (HP 1100, Equipped with UV detector and CROMASYL C-18 column (2.1*250 mm), Agilent). The bottom phase (53.4 gr) was found to contain 37 wt. % 3-MBPy and 58 wt. % bromine. The top phase (20.4 gr) gave rise to a residual amount of 3000 ppm of 3-MBPy and 380 ppm of bromine.

(11) B) Liquid bromine (160 gr) was introduced into a 1 L glass open vessel and bromine vapor was observed. Tetra-ethyl ammonium bromide (TEAB) aqueous solution (105 gr of 50 wt. % solution) was poured on the liquid bromine surface.

(12) Results: two phases were immediately formed upon the addition of the TEAB solution and no bromine vapor was observed following the phase separation. The bottom phase was solidified after about two hours.

(13) C) Liquid bromine (120 gr) was added to a 1 L glass open vessel and bromine vapor was observed. Tetra-butyl ammonium bromide (TBAB) aqueous solution (161 gr of 50 wt % solution) was poured on the liquid bromine surface.

(14) Results: two phases were immediately formed upon the addition of the tetra-butyl ammonium bromide solution and no bromine vapor was observed following the phase separation. Two hours later, the bottom phase turned into a gel-like phase. The obtained gel-like phase was liquefied utilizing 40 gr of liquid bromine.

Example 3

Foam Passivation of Bromine Spill

(15) A) Liquid bromine (50 gr) was added to a 1 L glass open vessel and bromine vapor was observed. A 25 gr solution containing 92 wt. % of TEAB solution of 50 wt. % tetra-ethyl ammonium bromide, and 8 wt. % of a foaming agent AR-AFFF FireAid-AR® 2000 solution was sprayed utilizing a pump spray on the liquid bromine surface.

(16) Results: A foam was immediately formed on top of the bromine surface, covering the bromine-air interface, and no bromine vapor emission was observed.

(17) An additional 30 gr liquid bromine was slowly added on top of the foam and did not cause any vapor release.

(18) Several hours later, the entire bromine source and the surface-coating foam phase were solidified.

(19) B) 50 gr of liquid bromine were poured into a 1 L glass open vessel and bromine vapor was observed. A 25 gr solution containing 50 wt. % 3-methyl-1-n-butyl pyridinium bromide (3-MBPy) solution (80 wt. %) and 8 wt. % of a foaming agent AR-AFFF FireAid-AR® 2000 was sprayed utilizing a pump spray on the liquid bromine surface.

(20) Results: A foam was immediately formed on top of the bromine surface, covering the bromine-air interface, no bromine vapor emission was observed.

(21) An additional 30 gr liquid bromine dripped on top of the foam and did not cause any vapor release.

(22) C) 50 gr of liquid bromine were poured into a 1 L glass open vessel. The bottom of the vessel was covered with liquid bromine and bromine vapor was formed. 25 gr of 92 wt. % 2-MEPy solution (50 wt. % 2-methyl-1-ethyl pyridinium bromide, (2-MEPy) mixed with 8 wt. % of a foaming agent AR-AFFF FireAid-AR® 2000 solution was sprayed on the liquid bromine surface.

(23) Results: A foam was immediately formed on top of the bromine surface, covering the bromine-air interface, and no bromine vapor emission was observed.

(24) An additional 30 gr liquid bromine dripped on top of the foam and did not cause any vapor release.

Example 4

Collecting Treated Bromine Solids

(25) Solid product of treated liquid bromine were obtained as described in examples 2B and 3. The solids were collected manually by spatula into a plastic container. No changes in the product was observed after a 3 months period.

Example 5

Collecting Treated Bromine Liquids

(26) Liquid product of treated liquid bromine obtained as described in example 2C was collected manually by suction into a plastic container. No changes in the product was observed after a 3 months period.

Example 6

Evaporation Rate Measurements

(27) The purpose of the study was to test the ability of quaternary ammonium salts added to liquid bromine to suppress release of bromine vapors. The study is based on monitoring a weight change for samples containing liquid bromine (Br.sub.2; control), 3-MBPy/Br.sub.2, TBAB/Br.sub.2 and TEAB/Br.sub.2 at various molar ratios as described in Table 1 herein below. The weight loss was measured under the same conditions as a reference.

(28) A sample of (33 ml) was placed on a balance (0.01 g) and the weight was set to zero. The weight change was recorded every 5 seconds. The experiment took place under ambient conditions.

(29) Results: As presented in FIGS. 1A and 1B and Table 1 herein below, it was demonstrated that even upon addition of a small amount of quaternary ammonium bromide to bromine a significant reduction of bromine evaporation occurs. A weight loss rate of 50.04 gr/hr was measured for liquid bromine by itself, and was reduced to 3.96 gr/hr in a system comprising 3-MBPy and bromine in a molar ratio of 1:3. Further weight loss rate reduction was achieved utilizing TEAB with the same molar ratio (1:3), yielding a minimal weight loss of 1.08 gr/hr.

(30) TABLE-US-00001 TABLE 1 Sample weight loss rate # composition ratio [gr/hr] 1 water — 1.44 2 Elemental Bromine — 50.04 3 3-MBPy/Br2 1:3 3.96 4 TBAB/Br2 1:6 3.24 5 TEAB/Br2 1:3 1.08 6 TEAB/Br2 1:7 1.8

Example 7

Effect of Quaternary Ammonium Salt on the Physical Form of the Complexed Bromine

(31) Different quaternary ammonium salts were tested to determine their ability to complex bromine in different molar ratios. Solutions of 3-methyl-1-n-butyl pyridinium bromide (3-MBPy), tetra-butyl ammonium bromide (TBAB) and tetra-ethyl ammonium bromide (TEAB) [50 wt. % solution, total of 0.25 mole quaternary ammonium salt] were mixed with liquid bromine in varied weights of 40, 80, 120, 160 and 200 gr in a glass container in a molar ratio as described in Table 2. The resultant lower phase obtained after the mixing was characterized according to the physical state and whether bromine vapor was observed after the complexation occurred.

(32) TABLE-US-00002 TABLE 2 Quaternary ammonium:bromine 3-MBPy TBAB TEAB 1:1 Liquid Liquid Solid 1:2 Liquid Gel - like Solid 1:3 Liquid Gel - like Solid 1:4 Liquid Gel - like Solid 1:5 Liquid Liquid Gel - like (slight (slight (slight bromine bromine bromine emission) emission) emission) 1:6 Liquid Liquid Liquid (slight (slight (slight bromine bromine bromine emission) emission) emission)

(33) As can be seen from Table 2, the physical form of the complexed bromine depends not only on the kind of quaternary ammonium salt utilized for its complexation but also might be dependent on the molar ratio between said quaternary ammonium salt and bromine. Furthermore, it can be seen that for 3-MBPy, TBAB and TEAB no bromine evaporation was observed up to a molar ratio of 1:4 Quaternary ammonium: bromine.

Example 8

Neutralization of Chlorine (Cl.SUB.2.) Gas with Quaternary Ammonium Bromide Alone and with Quaternary Ammonium Bromide/NaBr

(34) A. 460 gr 50 wt. % of 3-MBPy solution was inserted into a glass vessel. The glass vessel was vented, the solution was stirred and the emissions were trapped in a 20 wt. % NaOH trap.

(35) Cl.sub.2 gas was bubbled into the vessel. Cl.sub.2 gas addition was carried out from a chlorine gas compressed tank, which was controlled and recorded using a semi-analytical balance. Phase separation was observed after 30 gr Cl.sub.2 addition as can be observed in FIG. 2. The solution color became brighter during the Cl.sub.2 addition progress.

(36) A total of 2 mole (142 gr) chlorine gas were captured in the described 3-MBPy solution.

(37) B. 460 gr 50 wt. % of 3-MBPy solution was added into a glass vessel. 155 gr NaBr was added into the solution. The glass vessel was vented, the solution was stirred and the emissions were trapped in a 26 wt. % NaOH trap.

(38) Cl.sub.2 gas was bubbled into the vessel (for a duration of 105 minutes). Cl.sub.2 gas addition was carried out from a chlorine gas compressed tank, which was controlled and recorded using a semi-analytical balance. The solution's color became darker during the Cl.sub.2 addition progress as can be observed in FIG. 3. The chlorine gas addition was stopped upon observed gas emission in the trap.

(39) A total of 2.45 mole (174 gr) chlorine gas were captured in the described 3-MBPy:NaBr solution. The reaction was exothermic and the temperature reached 70.8° C. following the addition of 80 gr chlorine. Further addition of chlorine did not cause a further increase in temperature.

Examples 9 to 12

Eliminating Cl.SUB.2 .Gas Release by Counter Spraying of a Treatment Solution of Quaternary Ammonium Bromide/Inorganic Bromide

(40) The experimental set-up used for the next set of Examples is shown in FIG. 4. The experimental set-up consists of three major parts: feeding sources (1) and (2), a reaction chamber (3) and a gas trapping system (4). From the feeding sources, controlled quantities of Cl.sub.2 gas (2) and the treatment solution consisting of quaternary ammonium bromide and inorganic bromide salt (1) are delivered separately into the reaction chamber. The Cl.sub.2 inlet is located at the bottom part of the reaction chamber (column 3, which is a 30 L closed glass vessel). The solution is fed from tank (1) into column (3) in a counterflow fashion, by spraying through a nozzle (3o) positioned at the center of the top section of column (3).

(41) A chemical reaction between the Cl.sub.2 gas and the reaction solution takes place in the interior of column (3): Cl.sub.2 reduction by the bromide ion, and complexation of the elemental bromine formed by the quaternary ammonium halide. The atmospheric pressure inside the reaction chamber is balanced by permitting two-direction gas flow through the trapping system (4). The trapping system consists of three trapping vessels (M1, M2 and M3) connected in series from one end of the reaction chamber (column 3) to the exhaust. The first trap M1 consists of an empty vessel and is used to prevent the flow of trap solution into the reaction chamber (column 3) when a negative pressure is built up in the column. The other two traps (M2 and M3) are filled with sodium hydroxide solution (20-25 wt. %) to collect and neutralize Cl.sub.2 or Br.sub.2 gas escaping from the column (3). There is an activated carbon trap at the end (M4).

(42) The experimental set-up shown in FIG. 4 was used to perform a series of tests, the conditions of which are tabulated in Table 3 below. Briefly, a quantity of Cl.sub.2 gas (indicated in Table 3, column A) was released from cylinder (2) during a time period (indicated in Table 3, column B) through a bottom joint of an empty 30 L closed glass vessel (column 3). When the interior of the vessel started acquiring yellow color at the bottom, indicating accumulation of chlorine gas, a treatment solution consisting of TEAB and inorganic bromide salt was pumped from tank (1) and sprayed through a nozzle located at the top part of the vessel. The volume of the TEAB/M.sup.n+Br.sub.n solution supplied to the reaction vessel and its composition are indicated in Table 3, column C).

(43) The reaction between the Cl.sub.2 gas and the treatment solution TEAB/M.sup.n+Br.sub.n led to formation of a red product, either in a solid or liquid form (product phase is indicated in Table 3, column D), and consequently, internal negative pressure was created. As a result, the 1st trap (M1) was filled with sodium hydroxide solution drawn from the 2nd and 3rd traps (M2 and M3, respectively).

(44) Table 3 below summarizes the conditions of each experiment and the product formed.

(45) TABLE-US-00003 TABLE 3 A Cl.sub.2(g) B C D Example (gr) [min] [Treatment solution composition] Product phase 9 118 4 1.2 L: 840 gr TEAB (50 wt. %) + Solid 916 gr NaBr solution (45 wt. %) 10 155 10 5 L: 2940 gr TEAB (50 wt. %) + Mostly Liquid 3206 gr NaBr solution (45 wt. %) + 206 gr NaBr(s) 11 108 4:30 3 L: 1680 gr TEAB (50 wt. %) + Solid 1538 gr CaBr2 (52 wt. %) 12 245 3 1.2 L: 840 gr TEAB (50 wt. %) + Solid 769.2 gr CaBr2 (52 wt. %)

(46) No residual of Cl.sub.2 gas was detected (<10 ppm) in the 1.sup.st (M1), 2.sup.nd (M2) and 3.sup.rd (M3) traps, indicating complete absorption of the chlorine gas by the treatment solution consisting of TEAB/M.sup.n+Br.sub.n, and its conversion into harmless product which is readily removable from the reaction vessel.

Example 13 (Comparative)

Neutralization of Chlorine (Cl.SUB.2.) Gas

(47) The experimental set-up shown in FIG. 4 and described in detail above was used for the experiment. Cl.sub.2 gas (107 gr) was released (2) during a period of 5 minutes through a bottom joint of an empty 30 L closed glass vessel (3). During the first five minutes air bubbles were observed inside the sodium hydroxide trap M2, as Cl.sub.2 pushed out the air in the glass vessel (3). During the next nine minutes the color of the sodium hydroxide solution in the first sodium hydroxide trap (M2) changed to yellowish green. No bubbles were observed and no color change was visible in the 3rd trap (M3). After shutting down the Cl.sub.2 flow, N.sub.2 gas (5) was purged into the glass vessel (3) to wash out any remaining Cl.sub.2 gas inside the reaction vessel.

(48) At the end of experiment a positive weight change of 97.7 gr and 3.8 gr were determined in the first NaOH trap (M2) and second NaOH (M3) trap, respectively.

Example 14

Neutralization of Chlorine (Cl.SUB.2.) Gas

(49) 20 gr CaBr.sub.2 powder were dissolved in 105 gr of TEAB aqueous solution (50 wt. %) inside a 200 ml glass vessel (connected to a NaOH trap). Cl.sub.2 gas (32 gr) from pressure regulated tank was bubbled into the solution at a flow rate of 0.47 gr/min. The temperature during the experiment was in the range of 30-40° C. After 68 minutes, emission of Cl.sub.2 gas was observed in the NaOH trap, indicating the exhaustion of the TEAB/CaBr.sub.2 reagent. The process was stopped, and the final product solution was separated into two phases—an upper aqueous yellow phase and a reddish organic phase at the bottom, indicating accumulation of elemental bromine in the organic phase. The organic phase solidified after 1 hour.

Example 15 (of the Invention) and 16 (Comparative)

Testing Quaternary Ammonium Chloride in Complexation of Halogen

(50) The quaternary ammonium chloride chosen for the experiments was tetra ethyl ammonium chloride (TEACl).

(51) Bromine complexation was investigated (Example 15). 0.4 mole of liquid bromine (64 gr) were mixed with 0.1 mole of TEACl (50 wt. %) solution (36 gr). 3 equivalents (48 gr) of Bromine were complexed by the TEACl solution, the 4th equivalent addition led to the appearance of light bromine vapor emission.

(52) Chlorine complexation was investigated (Example 16). 10 gram Cl.sub.2 gas was bubbled into 108 gr TEACl solution (50 wt. %). The Cl.sub.2 emission was collected by sodium hydroxide solution (25 wt. %) trap. No weight change was observed in the TEACL solution, indicating that Cl.sub.2 was entirely adsorbed by the trap (namely, no Cl.sub.2 was captured by TEACl).