Sodium Hypochlorite Handbook
TABLE OF his handbook outlines recommendedmethods for handling, storing, andusing sodium hypochlorite. It alsoincludes information on themanufacture, physical properties,safety considerations and analyticalmethods for testing sodiumhypochlorite. Additional informationand contacts can be found tion Terminology5Manufacturing6Handling and Storage9Safety Handling11Unloading Tank Trucks14Physical Property Data16Methods of Analysis18Typical Storage Tank Installation23Important: The information presented herein, while not guaranteed, was prepared by technical personnel andis true and accurate to the best of our knowledge. NO WARRANTY OF MERCHANTABILITY OR OF FITNESSFOR A PARTICULAR PURPOSE, OR WARRANTY OR GUARANTY OF ANY OTHER KIND, EXPRESS ORIMPLIED, IS MADE REGARDING PERFORMANCE, SAFETY, SUITABILITY, STABILITY OR OTHERWISE. Thisinformation is not intended to be all-inclusive as to the manner and conditions of use, handling, storage,disposal and other factors that may involve other or additional legal, environmental, safety or performanceconsiderations, and Occidental Chemical Corporation assumes no liability whatsoever for the use of orreliance upon this information. While our technical personnel will be happy to respond to questions, safehandling and use of the product remains the responsibility of the customer. No suggestions for use areintended as, and nothing herein shall be construed as, a recommendation to infringe any existing patents orto violate any Federal, State, local or foreign laws.
INTRODUCTIONThis handbook provides informationconcerning sodium hypochlorite orbleach, solutions. An attempt has beenmade to give comprehensive coverageof the subject. If additional technicalinformation or specificrecommendations regarding sodableach solutions are desired, theTechnical Service Group of OccidentalChemical Corporation will be pleasedto provide assistance. Requests forsuch information should be made toyour local OxyChem representative.Some safety and handling informationhas been taken directly from theChlorine Institute’s Pamphlet 96 withthe permission of the ChlorineInstitute. Pamphlet 96 also containsadditional information on sodiumhypochlorite.For further information regardingcaustic soda and chlorine, refer to theappropriate OxyChem handbook.Sodium hypochlorite solutions haveattained widespread use in bleachingoperations and as disinfectants, bothin the home and in industry.Scheele, a Swedish chemist, isgenerally credited with discoveringchlorine in 1774. During hisexperiments, he found that a solutionof chlorine in water possessed definitebleaching properties. Since thereaction between chlorine and waterforms hydrochloric and hypochlorousacids, early textile bleachingexperiments were not successfulbecause of damaged cloth.In 1789, the French chemist Bertholletsucceeded in chlorinating a solution ofpotash, forming a potassiumhypochlorite solution. This solutionproved to be a more successful bleachfor textiles due to the absence ofhydrochloric acid. However, it nevergained more than limited usage in thebleaching field, primarily because ofthe high cost of potash.2In 1798, Tennant of England prepareda solution of calcium hypochlorite bychlorinating a slurry of relativelyinexpensive lime. The following yearhe patented a process for themanufacture of bleaching powderwhere chlorine gas was absorbed in adry lime hydrate.Labarraque succeeded, in 1820, inpreparing sodium hypochlorite bychlorinating a solution of caustic soda.Varying concentrations of this solutionhave found a multitude of applicationsso that the general public is now wellacquainted with the material. Thishandbook will discuss sodiumhypochlorite solutions.
PROPERTIES OF SODIUM HYPOCHLORITECHEMICAL PROPERTIESChlorine (Cl2) is the best overalldisinfectant, germicide, algaecide andanti-slime agent. Chlorination andfiltration of drinking water isresponsible for a nearly fifty percentreduction in deaths due to disease inmajor cities during the late 19th andearly 20th centuries and the nearelimination of typhoid fever. Infantsand children benefiting the most.Calcium hypochlorite was the firstchlorinating agent used.Chlorine also oxidizes and eliminatesorganic compounds and convertssome soluble metallic impurities intoinsoluble solids that can be removedby filtration.Chlorine is soluble in water to about7000 ppm at 68 F. It reacts with waterforming hypochlorous acid (HOCl). Inalkali solutions hypochlorous aciddissociates forming hypochlorite(OCl-). Chlorine, hypochlorous acidand hypochlorite exist together inequilibrium.Cl2 H2O HOCl OClIncreasing pH The figure below shows the effect pHhas on the equilibrium.Below pH 2 the equilibrium favorschlorine. Between pH 2 and 7.4hypochlorous acid predominates andabove pH 7.4 hypochloritepredominates.Hypochlorous acid is a significantlymore powerful oxidizer anddisinfectant than hypochlorite. Bestbiological control is achieved in the pHrange of 5 to 7 where hypochlorousacid is predominate.Hypochlorous acid is extremelyunstable. It is much easier to handlethe more stable hypochlorites. Theterm hypochlorites refers to the salt ofhypochlorous acid. One of the bestknown hypochlorites is sodiumhypochlorite, the active ingredient inbleach. The molecular formula forsodium hypochlorite is NaOCl.Na OCl- NaOClsodiumhyposodiumcation chlorite hypochloriteanionThe most common method forproducing sodium hypochlorite is toreact chlorine with sodium hydroxide(NaOH). The reaction by-products aresodium chloride (salt, NaCl) and water(H2O).1) Cl2 2 NaOH NaOCl NaCl H2O HEATSYNONYMS Hypo Liquid bleach Hypochlorite Soda bleach Bleach Javel water Chlorine bleachAPPLICTIONS Disinfection Removal of ammonia Control taste and odor Hydrogen sulfide oxidation Iron and manganese oxidation Destruction of organic matter Color reduction Control of slime and algae Laundry BleachingOXIDIZING POWEREq. 2 shows the oxidation of twomoles of potassium iodide (KI) withone mole of sodium hypochlorite in asolution of acetic acid to iodine (I2).2) NaOCl 2 CH3COOH 2 KI NaCl 2 CH3COOK I2 H2OEq. 3 shows the oxidation of twomoles of potassium iodide with onemole of chlorine to iodine.3) Cl2 2 KI 2 KCl I2Given that one mole of sodiumhypochlorite can oxidize the sameamount of iodide to iodine as one moleof chlorine they have equal oxidizingpower. Therefore, the “availablechlorine” in sodium hypochloriteequals the amount of chlorine used toproduce it and sodium chloride (seeEq. 1) in oxidizing power.DECOMPOSITION REACTIONSSodium hypochlorite is stable abovepH 12 where the less reactivehypochlorite is predominant andhypochlorous acid is virtuallynonexistent.Decomposition is by Eq. 4 and 5.4) 3 NaOCl NaClO3 2 NaCl5) 2 NaOCl O2 2 NaClEq. 4 is the major decompositionreaction forming chlorate (ClO3-) andchloride (Cl-). This reaction istemperature and concentrationdependent; it is not catalytic. Eq. 5 iscatalytic, forming oxygen (O2) andchloride. Trace metals such as nickel,cobalt and copper form metal oxides,which cause catalytic decomposition.Light also catalyzes this reaction.
PROPERTIES OF SODIUM HYPOCHLORITESSTABILITYAlthough more stable thanhypochlorous acid, sodiumhypochlorite is unstable. It startsdecomposing immediately. Withproper care, the rate of decompositioncan be reduced such that relativelystable solutions can be prepared.The stability and shelf life of ahypochlorite solution depends on fivemajor factors: Hypochlorite concentration.pH of the solution.Temperature of the solution.Concentration of certain impuritieswhich catalyze decomposition. Exposure to light.Low concentration hypochloritesolutions decompose slower than highconcentration hypochlorite solutions.Fifteen weight percent sodiumhypochlorite will decomposeapproximately 10 times faster than5 wt% sodium hypochlorite at 25 C.The pH has a significant effect on thestability of sodium hypochloritesolutions. Below pH 11 thedecomposition of sodium hypochloriteis significant due to the shift in theequilibrium in favor of the morereactive hypochlorous acid. A pHbetween 12 and 13 gives the moststable solution. This equates to 0.4 to4.0 grams per liter (gpl) excess NaOH.Greater concentrations will notimprove the stability. Excessively highalkalinity will damage textiles andretard the bleaching and disinfectingactions of the hypochlorite.Temperature influences the stability ofhypochlorite solutions. Care should betaken to keep solutions away fromheat, as higher temperatures increasethe decomposition rate. Fifteenpercent sodium hypochloritedecomposes five times faster at 45 Cthan at 25 C. Although low storagetemperatures improve the stability ofhypochlorite solutions, freezing shouldbe avoided. Sodium hypochloritesolutions will freeze at differenttemperatures depending on theconcentration of the solution. Thirteenwt% sodium hypochlorite freezes at-22.5 C compared to 6 wt% sodiumhypochlorite which freezes at -7.5 C.The quality and stability of sodiumhypochlorite solutions can be affectedby the concentration of certainimpurities. Trace metals such asnickel, cobalt and copper forminsoluble metal oxides, which causethe bleach to catalytically decomposeby Eq. 5. These trace metals, as wellas iron, calcium and magnesium, formsediment and may discolor the bleachsolution.Potential sources for these impuritiesinclude raw materials, processingequipment and product storagecontainers. The most common sourcefor these metals, particularly nickeland copper, is the caustic soda.Diaphragm cell caustic soda typicallycontains a higher concentration ofthese metal catalysts than membranegrade. However, stable bleach can bemade from diaphragm grade causticsoda.Some techniques to minimize theconcentration of impurities in thefinished product are listed below. Polish the finished bleach with a 0.5to 1 micron filter. This will removeimpurities which promote bleachdecomposition and/or degrade thevisual appearance. Use plastic or plastic lined tanks andpiping systems to reduce metalscontamination. Use soft water for dilution. Allow finished bleach to settle untilclear and decant before packaging.4The most effective of these techniquesis polishing the finished bleach with a0.5 to 1 micron filter. It removesinsoluble metal oxides that catalyzedecomposition and sediments thataffect product appearance. This levelof filtration is difficult and expensive toachieve using cartridge type filters. Afilter that uses a filter aid such asdiatomaceous earth is needed.Sunlight (ultraviolet light) catalyzeshypochlorite decomposition by Eq. 5.Opaque (non-translucent)containers for hypochlorite solutionswill reduce decomposition due to light.In summary:1. Low concentration solutions aremore stable than highconcentration solutions. Dilutingsoon after receiving will reduce thedecomposition rate. Use soft waterto minimize impurities. Use coldwater to reduce the temperaturethus reducing the decompositionrate.2. A pH between 12 and 13 gives themost stable solution. Less thanpH 11 decomposition is significant.Greater than pH 13 there is noimprovement.3. Keep solutions away from heat, ashigher temperatures increasedecomposition.4. Filter to remove insoluble metaloxides that catalyzedecomposition and sediments thataffect product appearance. Usetitanium, plastic or plastic linedtanks and piping systems toreduce metals contamination.5. Store in opaque (non-translucent)containers to preventdecomposition due to sunlight.
SODIUM HYPOCHLORITE CONCENTRATION TERMINOLOGYChlorine is the standard against whichoxidizers are compared The term“available chlorine” refers to theamount of chlorine equivalent inoxidizing power. It is a measure ofstrength and bleaching power and isused to express the concentration ofbleach solutions. Available chlorine isusually expressed as grams per liter(gpl) or weight percent (wt%). Thestrength of hypochlorite solutions mayalso be expressed as wt% sodiumhypochlorite.Trade percent available chlorine isanother way to express the strength ofhypochlorite solutions. Similar to0.4 (11.0)gpl available chlorineTrade% available chlorineSpecific Gravity @ 20 C% excess NaOHwt% available chlorinewt% NaOClSpecific Gravity @ 20 C% excess NaOHwt% available chlorinewt% NaOClSpecific Gravity @ 20 C% excess NaOHwt% available chlorinewt% NaOClSpecific Gravity @ 20 C% excess NaOHwt% available chlorinewt% NaOClSpecific Gravity @ 20 C% excess NaOHwt% available chlorinewt% NaOClSpecific Gravity @ 20 C% excess NaOHwt% available chlorinewt% NaOClSpecific Gravity @ 20 C% excess NaOHwt% available chlorinewt% NaOClSpecific Gravity @ 20 C% excess NaOHwt% available chlorinewt% NaOCl404grams per liter available chlorineexcept instead of grams per liter itsgrams per 100 ml. Given that one literis 1000 ml, trade percent is the gplavailable chlorine divided by 10.It is important to specify theconcentration units wheneverdescribing the strength of hypochloritesolutions. For example, 5.25 wt%sodium hypochlorite is equivalent to5.0 wt% available chlorine orapproximately 53.8 gpl availablechlorine.The table below converts from oneconcentration to another.50560680810010Conversionswt% available Cl2 gpl available Cl210 * SGsolutionwt% NaOCl 1.05 * wt% available Cl2gpl available Cl2wt% NaOCl 1.05 *10 * SGsolutionNote:74.44 MW NaOCl, 70.90 MW Cl21.05 74.44 / 70.90453.6 g/lb * 8.34 lb/gal10 3.7854 l/gal * 100%1201214014150151601618018200200.5 (12.1)1 (12.4)2 (12.7)4 (13.0)6 (13.2)gpl excess NaOH (approximate pH)8 (13.3)10 15.86%16.65%
MANUFACTURING SODIUM HYPOCHLORITEThere are commercially availablecontinuous bleach systems capable ofproducing 25 to 150 gpm of 160 gplavailable chlorine. These systemscome skid mounted, fully instrumentedand include all the operating disciplineand training. The intent of this sectionis to provide an overview of themanufacturing process.Chlorine reacts with sodium hydroxideto produce sodium hypochloriteaccording to Eq. 6.Based on the ratio of the molecularweights, 1 pound of chlorine reactswith 1.13 pounds of sodium hydroxideto produce 1.05 pounds of sodiumhypochlorite. This does not include theexcess sodium hydroxide needed forstability. The exact ratio of chlorineand caustic soda depend on thequality of the dilution water (hard orsoft) and amount of excess sodiumhydroxide in the final product to namea few.The approximate amount of rawmaterials needed to produce a givenconcentration of bleach can becalculated using Eq. 7 through 14.Caustic soda solutions are not 100%sodium hydroxide; the calculationstake this into account. Chlorine isassumed to be 100% (99.5% min).6)Cl2 2 NaOH NaOCl NaCl H2O 24,700 caloriesMW 70.9180.0074.45Ratio 1.001.131.05Chlorine7a) lb Cl2 wt% NaOCl / 1.05 / 100 * SGbleach * 8.34 lb/gal * gal bleach7b) lb Cl2 wt% available Cl2 / 100 * SGbleach * 8.34 lb/gal * gal bleach7c) lb Cl2 gpl available Cl2 * 3.7854 l/gal / 453.6 g/lb * gal bleachCaustic Soda8) lb NaOH lb Cl2 * 1.13 lb NaOH/lb Cl29a) lb XS NaOH wt% XS NaOH / 100 * SGbleach * 8.34 lbs/gal * gal bleach9b) lb XS NaOH gpl XS NaOH * 3.7854 l/gal / 453.6 g/lb * gal bleach10) lb caustic soda (lb NaOH lb XS NaOH) / wt% caustic soda11) gal caustic soda lb caustic soda / 8.34 lb/gal / SG caustic sodaWater12) lb water gal bleach * 8.34 lb/gal * SGbleach - lb Cl2 - lb caustic soda13) gal water lb water / 8.34 lb/gal14) Diluted caustic soda %NaOH (lb NaOH lb XS NaOH) / (lb caustic soda lb water) * 100Example:Make 1,000 gallons of household bleach, 5.25 wt% sodium hypochlorite using20% diaphragm caustic soda.Given: 5.25 wt% sodium hypochlorite equates to 5.00 wt% available chlorine, 5.25wt% NaOCl / 1.05 5.00% available Cl2 Specific gravity of 20% diaphragm caustic soda is 1.2263 (see chart, pg 17) We know a pH between 12 and 13 makes the most stable bleach solutions.This equates to 0.4 to 4.0 gpl XS NaOH. Specific Gravity for a 5 wt% available chlorine bleach solution with 2 gpl XSNaOH is 1.076 (see chart, pg 5)7b) 5.00 wt% available Cl2 / 100 * 1.076 * 8.34 lb/gal * 1,000 gal bleach 449 lbCl28) 449 lb Cl2 * 1.13 lb NaOH/lb Cl2 507 lb NaOH9b) 2 gpl XS NaOH * 3.7854 l/gal / 453.6 g/lb * 1000 gal bleach 17 lb XS NaOH10) (507 lb NaOH 17 lb XS NaOH) / (20% caustic soda / 100) 2,620 lb 20%caustic soda11) 2,620 lb 20% caustic soda / 1.2263 / 8.34 lb/gal 256 gal 20% caustic soda12) (1,000 gal bleach * 8.34 lb/gal * 1.076) – 449 lb Cl2 – 2,620 lb 20% causticThe manufacturing process for making soda 5,902 lb waterbleach can be batch or continuous and 13) 5,902 lb water / 8.34 lb/gal 708 gal wateruse gaseous or liquid chlorine.14) (507 lb NaOH 17 lb XS NaOH) / (2,620 lb 20% caustic soda 5,902 lbTypically they are continuous and usewater) * 100 6.15% diluted caustic sodaliquid chlorine. The manufacturingprocess can be broken down intoseveral unit operations; causticThe table on page 8 shows the rawmaterials for making 1,000 gallons ofbleach in various concentrations from10 to 200 gpl available chlorine. Thetable also shows the gallons of bleachthat can be produced from a 100 lbcylinder, 150 lb cylinder and toncontainer of chlorine.6
MANUFACTURING SODIUM HYPOCHLORITESodium Hypochlorite Manufacturing ProcessWaterCaustic SodaCaustic dilution, chlorination, filtration anddistribution. Above is a simple processflow diagram.During caustic dilution heat isgenerated. For instance 50% causticsoda can arrive at temperatures ashigh as 110 F and after dilution with70 F water to 20% the finaltemperature is 130 F.During chlorination heat is alsogenerated. The amount of heatgenerated is 24,700 calories. SeeEq.6. This equates to 627 BTU/lb ofgaseous chlorine. By using liquidchlorine the heat generated is reducedby 109 BTU/lb (heat of vaporization ofchlorine @ 70 F) or 518 BTU/lb ofliquid chlorine. Using liquid chlorinenot only generates less heat, but alsoeliminates the need for an expensivechlorine vaporizer and everything thatgoes along with it (maintenance,controls, steam, etc.).Bas
grade. However, stable bleach can be made from diaphragm grade caustic soda. Some techniques to minimize the concentration of impurities in the finished product are listed below. Polish the finished bleach with a 0.5 to 1 micron filter. This will remove impurities which promote bleach decomposition and/or degrade the visual appearance.
Hydrofluorosilicic Acid Hydrogen Peroxide 35% Lead-acid Batteries Oxygen – Gas & Liquid Ozone Phosphoric Acid Potassium Permanganate Road Salt Sodium Bisulfate Sodium Bisulfite Sodium Carbonate or Soda Ash Sodium Hydroxide or Caustic Soda Sodium Hypochlorite Sodium Permanganate Sulfur Dioxide Sulfuric Acid 38 Sect 311 & 312 Threshold Review .
Preparation of Cyclohexanone by Hypochlorite Oxidation In this experiment we will prepare cyclohexanone from cyclohexanol using hypochlorite oxidation. We will use common household bleach that is a 5.25% (0.75 M) aqueous solution of sodium hypochlorite. The overall reaction is shown in Figure 8.1. Na O Cl CH 3 C O OH OH HOCl O HOCl H 2 O O C .
The average Canadian diet contains about 3400mg of sodium per day. A low sodium diet means limiting sodium intake to 1500 - 2300mg per day. You can use the guidelines in this education booklet to help you follow a low sodium diet. How do I limit my sodium intake? The key steps to following a low sodium diet are to: 1.
Calcium hypochlorite should always be predissolved before adding it to a fiberglass pool to - prevent bleaching or staining of the surfaces. Calcium hypochlorite is used at a rate of one pound per 10,000 gallons of pool water. Lithium hypochlorite is a quicker dissolving chemical, which may be added directly to a fiberglass pool.
You are invited to bring along samples of bleach containing cleaning products from home if you like. Be warned that colored cleaning products may mask the color change signifying the endpoint of the titration thus producing less accurate results. The first step of the bleach analysis reacts sodium hypochlorite with excess iodide and hydrogen ions:
(Medin ),steelK-reamer(Mani),andNiTiH-files(Polin-tech ). The following irrigation solutions were used: 2.0% sodium hypochlorite (Chema-Elektromet), 5.25% sodium hypochlorite (Cerkamed), 40.0% citric acid (Cerkamed), 0.2% chlorhexidine digluconate—Gluco-Hex (Cerk
5.1.1 The E-Series Commercial Chlorine Generator by electrolysis creates chlorine to sanitize the pool using the salt molecules (NaCL) in the water. A small electric charge is applied across a set of titanium plates inside the Electrolytic Cell(s). This produces Sodium Hypochlorite (NaOCl). In water, Sodium Hypochlorite dissociates
Note that measuring specific gravity at the same temperature as the bleach sample temperature used in the bleach strength test. Weight % available chlorine x NaOCl/Cl 2 or x 74/71 or 1.05 weight % NaOCl Weight % sodium hypochlorite g/L available chlorine x 1.05 (10 x specific gravity) or trade % Available Cl 2 x 1.05 specific gravity
