Week 2 Official Lecture Module 2021 IND. CHE PDF

TECHNOLOGICAL UNIVERSITY OF THE PHILIPPINES VISAYAS Capt. Sabi St., City of Talisay, Negros Occidental College of Engineering Technology Office of the Program Coordinator LEARNING MODULE CHT 413B G...

TECHNOLOGICAL UNIVERSITY OF THE PHILIPPINES VISAYAS Capt. Sabi St., City of Talisay, Negros Occidental College of Engineering Technology Office of the Program Coordinator LEARNING MODULE CHT 413B General Industrial Chemistry DEPARTMENT: Chemical Engineering Technology COMPILED BY: ALPHA J. HERMOSURA 2020 This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  VISION The Technological University of the Philippines shall be the premier state university with recognized excellence in engineering and technology at par with leading universities in the ASEAN region. MISSION The University shall provide higher and advanced vocational, technical, industrial, technological and professional education and training in industries and technology, and in practical arts leading to certificates, diplomas and degrees. It shall provide progressive leadership in applied research, developmental studies in technical, industrial, and technological fields and production using indigenous materials; effect technology transfer in the countryside; and assist in the development of small-and- medium scale industries in identified growth center. (Reference: P.D. No. 1518, Section 2) QUALITY POLICY The Technological University of the Philippines shall commit to provide quality higher and advanced technological education; conduct relevant research and extension projects; continually improve its value to customers through enhancement of personnel competence and effective quality management system compliant to statutory and regulatory requirements; and adhere to its core values. CORE VALUES T - Transparent and participatory governance U - Unity in the pursuit of TUP mission, goals, and objectives P - Professionalism in the discharge of quality service I - Integrity and commitment to maintain the good name of the University A - Accountability for individual and organizational quality performance N - Nationalism through tangible contribution to the rapid economic growth of the country S - Shared responsibility, hard work, and resourcefulness in compliance to the mandates of the university This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  iii TABLE OF CONTENTS TUP Vision, Mission, Quality Policy, and Core Values…………………………. ii Table of Contents……………………………………………………………..……. iii Course Description..……………………………………………………….. iv Learning Outcomes………………………………………………………… iv General Guidelines/Class Rules…………………………………………… iv Grading System ………………………………………………………….... iv Learning Guide (Week No. 1) …………………………………………….. 1 Topic/s …………………………………………………………….. 1 Expected Competencies …………………………………………... 1 Content/Technical Information …………………………………… 1 Progress Check …………………………………………………… References ………………………………………………………… Learning Guide (Week No. 2) …………………………………………….. Topic/s …………………………………………………………….. Expected Competencies …………………………………………... Content/Technical Information …………………………………… Progress Check …………………………………………………… References ………………………………………………………… Learning Guide (Week No. 3) …………………………………………….. Topic/s …………………………………………………………….. Expected Competencies …………………………………………... Content/Technical Information …………………………………… Progress Check …………………………………………………… References ………………………………………………………… Learning Guide (Week No. 4) …………………………………………….. Topic/s …………………………………………………………….. Expected Competencies …………………………………………... Content/Technical Information …………………………………… Progress Check …………………………………………………… References ………………………………………………………… References ………………………………………………………………………….. About the Author/s ………………………………………………………………... This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  iv COURSE DESCRIPTION The subject deals with the study of physical inorganic chemistry in applied settings. Basic foundational concepts in industrial processing will be discussed, including raw materials sourcing and processing, intermediates and conversion of chemical materials to final products, process optimisation and purification processes. LEARNING OUTCOMES 1. Describe the origin of raw materials used in the chemical and allied industries. 2. Analyze how chemical raw materials are processed into finished products. 3. Identify/Discover areas where finished products are applied or used. GENERAL GUIDELINES/CLASS RULES 1. Make-up exams and quizzes will only be given with prior approval of the professor and under exceptional circumstances. For excused absences during the exam, the university policy will be followed. 2.Students are not allowed to leave the classroom once the class has started, unless extremely necessary. Students who leave the classroom without any valid reason will be marked absent. 3.Students are expected to comply strictly with the university’s rule on dress code, class tardiness and attendance. 4.Cell phones or any e-gadgets must be turned off or put in a silent mode during class hours. 5.Late homework or projects will not be accepted. Students are expected to maintain complete honesty and integrity in their academic work. Acts of academic dishonesty, such as cheating, plagiarism, or inappropriately using the work of others to satisfy course requirements, will not be tolerated and may result in failure of the affected assignments and/or failure of this class. Students with Special Needs: A student with special medical needs, is advised to inform the instructor as to how he/she can best assist him/her. All information will be considered confidential. GRADING SYSTEM The student will be graded according to the following: Average of examinations - 40% Average of assessment - 60% Prelim Grade : [(Prelim Exam x.0.40) + (Assessment x 0.60)] x 0.30 Midterm Grade : [(Midterm Exam x.0.40) + (Assessment x 0.60)] x 0.30 End term Grade : [(Final Exam x.0.40) + (Assessment x 0.60)] x 0.40 Final Grade : Prelim Grade + Mid-Term Grade + End Term Grade The passing grade for this course is 5.0. This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  1 LEARNING GUIDE Week No.: __2__ TOPIC/S: Chlor-Alkali Industries EXPECTED COMPETENCIES: At the end of the lesson, you should be able to: 1. list the important products from the chlor-alkali industries; 2. identify the raw materials used to manufacture the different products from the chlor-alkali industries; 3. explain the process/es involved in the chlor-alkali industry; 4. describe important uses/applications of the products in the chor-alkali industry; and 5. cite reason/s in support of the chlor-alkali industry. CONTENT/TECHNICAL INFORMATION: I INTRODUCTION The manufacture of soda ash, caustic soda, and chlorine is one of the most important heavy chemical industries.The three products are sold almost entirely to industry for the production of soap and detergents, fibers and plastics, glass, petrochemicals, pulp and paper, fertilizers, explosives, solvents, and other chemicals. The name chlor-alkali comes from the two main products of the process, chlorine and the alkali, sodium hydroxide (NaOH, lye/caustic soda), which are commodity chemicals required by industry. The value of these products is what makes the chlor-alkali industry so important. Soda ash (Na2CO3) is a lightweight solid, moderately soluble in water, usually containing 99.3 % Na2CO3. It is sold on the basis of its sodium oxide content, which is generally 58%. Figure 2.1 Soda ash (Source:https://insidechem.blogspot.com/2017/04/test-method-for-sodium-carbonate- soda.html) This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  2 Pure caustic soda (NaOH) is a brittle white solid that readily absorbs moisture and carbon dioxide from the air. It is sold on the basis of its Na2O content and usually contains about 76% Na2O corrosive to the skin. Figure 2.2 Caustic soda (Source: https://www.turraco.com/energy-and-industrial-chemicals-caustic-soda.html) Chlorine is a chemical used in industry and in household cleaning products. At room temperature, chlorine is a gas. It has a yellow-green color, and a pungent, irritating odor similar to bleach. Usually, it is pressurized and cooled for storage and shipment as an amber- colored liquid. Chlorine does not catch fire easily, but may combine with other common substances to form explosive compounds. Figure 2.3 Chlorine (Source: https://slideplayer.com/slide/14037406/) This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  3 II MANUFACTURE OF SODA ASH A. Raw Materials The Solvay process (1861) uses salt, limestone, and coke or natural gas as its raw materials and uses ammonia as a cyclic reagent. The LeBlanc (1773) process uses salt cake with carbon and limestone. B. Manufacturing Process 1. LeBlanc process Before the Solvay process was developed, the LeBlanc process was in universal use. It was based on roasting salt cake with carbon and limestone in a rotary furnace and subsequently leaching of the product with water. The crude product of the reaction was called black-ash. It was leached cold whereupon some hydrolysis of sulfides took place. These were changed to carbonate by treatment with the carbon dioxide-containing gases from the black ash furnace. The resulting sodium carbonate solution was concentrated to obtain crystalline sodium carbonate, which was then dried or calcined. No Le Blanc process plant was ever built in the US, and none is now being operated anywhere in the world. Figure 2.4 Flow Diagram of the LeBlanc Process (Source: https://slideplayer.com/slide/4385873/) This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  4 2. Solvay Process (Ammonia-soda Process) The present synthetic process for the manufacture of soda ash is the Solvay Process. Ernest Solvay developed this process, also known as the ammonia-soda process, which after a few years reduced the price of soda ash almost one-third, and completely displaced the Le Blanc by 1915. The success of the Solvay process depends upon the fact that ammonia, carbon dioxide, and water in the proper proportions react to form ammonium bicarbonate, which is relatively insoluble in the solution used and can be filtered out and roasted to form soda ash. The ammonium chloride formed is converted back to ammonia by reaction with lime, the calcium chloride thus formed being the principal pollutant from the process. The over-all reaction for the process is CaCO3 + 2NaCl Na2CO3 + CaCl2 By 1982, only one Solvay plant continues to operate in the US. “Natural” soda from the Wyoming deposits now dominates the domestic market and has a brisk export trade as well. Figure 2.5 Flow Diagram of the Solvay Process (Source: https://scienceeasylearning.wordpress.com/2015/05/25/preparation- of-sodium-carbonate-by-solvay-process/) The Green River Basin of southwestern Wyoming is underlaid with huge deposits of trona, naturally occurring sodium sesquicarbonate (Na2O3. NaHCO3.2H2O); some is also found in dry lakes in California. The Wyoming beds are worked by conventional underground mining techniques. Very little processing of trona is required. Solution, clarification, filtration, crystallization, drying, and calcining suffice. Depending on temperature and CO2 This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  5 concentration, sesquicarbonate, sodium carbonate monohydrate, or sodium bicarbonate can be the final product. Figure 2.6 Trona is mined underground, using heavy equipment like the Continuous Miner pictured below. The ore is then carried to the surface and processed. (Source: https://www.wyomingmining.org/minerals/trona/) C. Uses Soda ash can be seen in almost everything that we use every day. The following applications show the importance of soda ash. Industrial Applications Since soda ash is a soluble substance, it can be used in various chemical reactions – mostly as a coloring agent, detergent, fertilizer, as well as in enameling and petroleum industry. Glass Manufacture In the production of glass, glass containers, fiberglass insulation, and many others, soda ash is needed especially because it reduces the melting point of silica. Detergent Manufacture Soda ash can replace the phosphates that are used in making household detergents. Also, there are various cleaning products and dishwashing soaps that contain soda ash in their formulations. Other uses of Soda Ash 1. It can help in removing stains, alcohol, and grease on clothes – also in coffee pots and espresso makers. This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  6 2. It can increase the alkaline level in swimming pools which can help in maintaining the pH Levels to balance the water. 3. It can also be used for dyeing clothes. 4. It can effectively clean the air. 5. It can soften water. 6. It can be used as fertilizers. III MANUFACTURE OF SODIUM BICARBONATE Sodium bicarbonate, baking soda, bicarb or bicarbonate of soda, or sodium hydrogen carbonate (IUPAC name) is a white solid that is crystalline but often appears as a fine powder. It has a slightly salty, alkaline taste. The natural mineral form is nahcolite (natural sodium bicarbonate), a component of the mineral natron and is found dissolved in many mineral springs. The Piceance Basin of Colorado has nahcolite beds among the oil-shale deposits. Figure 2.7 Baking soda (Source: https://www.worldofchemicals.com/585/chemistry-articles/sodium- bicarbonate-discovery-production-uses.html) Sodium bicarbonate is made by treating a saturated solution of soda ash with CO2 in a contacting tower at about 40OC. Here, the saturated soda ash solution moves from the top of the tower downward. The suspension of bicarbonate formed is removed from the bottom of the tower, filtered, and washed on a rotary drum filter. The cake is then centrifuged and dried on a continuous belt conveyor at 70OC. After filtering, washing, and drying, the sodium bicarbonate crystals—baking soda, are sorted by particle size and packaged appropriately. Bicarbonate made in this fashion is about 99.9% pure. This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  7 Figure 2.8 An illustration of the baking soda manufacturing process. (Source: https://www.madehow.com/Volume-1/Baking-Soda.html) Uses of baking soda Sodium bicarbonate is widely used in the food industry, in making rubber, in pharmaceuticals as an antacid, in fire extinguishers, soap and detergents, rug cleaners, animal feeds, and textiles, in leather and paper manufacturing, for flue-gas scrubbing, and for many other diversified small-scale uses. The crude material from natural deposits could be used directly for flue-gas scrubbing to remove sulfur dioxide, or as an additive for animal feed. IV MISCELLANEOUS ALKALIES Various alkalies of different strengths are consumed commercially, according to the contained amounts of NaOH, Na2CO3, or NaHCO3. 1. Causticized soda ash (soda ash with 10 to50% caustic) - for bottle washing and metal cleaning 2. Modified sodas (soda ash with 25 to 75% NaHCO3) - for mild-alkali demands, as in tanning industry 3. Sodium sesquicarbonate, (natural trona) - can be used without modification for wool scouring and in laundering 4. Sal soda (Na2CO3.10H2O) - also known as washing soda or soda crystals. V MANUFACTURE OF CHLORINE AND CAUSTIC SODA This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  8 Before the electrolytic method of making sodium hydroxide and chlorine (chlor-alkali process) became widely used, sodium hydroxide was made from soda ash by the lime-soda process. The soda ash as aqueous Na2CO3 is reacted with slaked lime (Ca(OH)2) according to the following equation: Na2CO3(aq) + Ca(OH)2(s) 2NaOH(aq) + CaCO3(s) The chlor-alkali process has gradually replaced the lime-soda process. Raw Materials The chlor-alkali industry uses rock salt, a natural deposit of sodium chloride. The aqueous sodium chloride solution, referred to as brine contains Na+, Cl-, H+ and OH - ions. Electrolysis of this solution produces simultaneously chlorine, sodium hydroxide and hydrogen in the ratio of 1:1.13:0.028 Manufacturing process Chlorine and caustic soda are produced almost entirely by the electrolysis of aqueous solutions of alkali metal chlorides, or from fused chlorides. Principal products of the reaction are NaOH, Hydrogen, and Chlorine. Brine electrolysis produces chlorine at the anode and hydrogen along with the alkali hydroxide at the cathode. Much of this hydrogen is used to produce hydrochloric acid, ammonia, hydrogen peroxide, or is burned for power and/or steam production. Electrolytic cell design must keep chlorine and the alkali hydroxide from mixing. At present, three types of electrolytic cell dominate the industry, the diaphragm cell, the membrane cell, and the mercury cell. 1. Diaphragm Cells Diaphragm cells contain a porous diaphragm, usually made of asbestos fibers, to separate the anode from the cathode. This allows ion to pass through by electrical migration but reduces the diffusion of products. Anodes have usually been made of graphite, cathodes of cast iron. The brine is introduced into the anode compartment and flows through the diaphragm into the cathode compartment. When an electric current passes through the brine, the salt's chlorine ions and sodium ions move to the electrodes. Chlorine gas is produced at the anode. At the cathode, sodium ions react with water, forming caustic soda and hydrogen gas. Some salt remains in the solution with the caustic soda and can be removed at a later stage. The general equation for the reaction is: 2NaCl + 2H2O Cl2 + H2 + 2NaOH This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  9 Figure 2.9 The diaphragm cell for the manufacture of chlorine. (Source: https://www.chemguide.co.uk/inorganic/group7/diaphragmcell.html) Diaphragms permit the construction of compact cells of lowered resistance because the electrodes can be placed close together. The diaphragms become clogged with use and must be replaced regularly. The diaphragm permits a flow of brine from anode to cathode and thus greatly lessens or prevents side reactions. Cells with metal cathodes (titanium coated with rare earth oxides, platinum or noble metals, or oxides ) rarely develop clogged diaphragms and operate for 12 to 24 months without requiring diaphragm replacements. Diaphragms made of corrosion-resistant plastics will increase service life and remove the environmentalist’s objection to any process that may release asbestos fibers into the environment. A major advantage of the diaphragm cell is that it can run on dilute (20%), fairly impure brine, which produce dilute sodium hydroxide ( 11% NaOH with 15% NaCl) contaminated with sodium chloride as a product.The usual shipping strength of 50% is required, and approximately 2 600 kg of water must be evaporated to produce a ton of 50% caustic. Salt is not very soluble in concentrated caustic solution, and the small amount of chloride ion which remains is highly objectionable to rayon manufacture. Sodium chlorate is objectionable when caustic is used in the manufacture of glycerin, pentaerythritol, sodium sulfate, sodium hydrosulfate, cellophane, and other chemicals.A catalytic reduction with hydrogen can remove this. 2. Membrane Cells The membrane cell is similar to the diaphragm cell, and the same reactions occur. The main difference is that the two electrodes are separated by an ion-selective This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  10 membrane, rather than by a diaphragm. The membrane allows cations to pass through it between compartments of the cell. It does not allow anions to pass through. The purpose of the membrane is to exclude OH- and Cl- ions from the anode chamber, making the product lower in salt than from a diaphragm cell. Brine is pumped into the anode compartment, and only the positively charged sodium ions pass into the cathode compartment, which contains pure water. Figure 2.10 The membrane cell for the manufacture of chlorine. (Source:https://chem.libretexts.org/Courses/University_of_British_Columbia/UBC_CHEM_ 154%3A_Chemistry_for_Engineering/11%3A_Electrochemistry/11.6%3A_Industrial Electrolysis_Processes) With diaphragm cells, back migration of ions is controlled by the rate of flow of fluid through the diaphragm, regulated by careful control of liquid levels in the compartments. Membrane cells separate the compartments with porous chemically active plastic sheets that allow sodium ions to pass but reject hydroxyl ions. Membrane cells operate using a more concentrated brine and produce a purer, more concentrated product (28% NaOH containing 50 ppm of NaCl; some claiming 40% NaOH product). Membranes are more readily clogged than diaphragms, so the necessity to pretreat the brine fed in order to remove calcium and magnesium before the electrolysis. 3. Mercury Cells Mercury cells operate differently from diaphragm and membrane cells. The anodes are either graphite or modified titanium, and the cathode is a flowing pool of mercury. The electrolysis produces a mercury-sodium alloy (amalgam), decomposed in a separate vessel according to the reaction: 2 Na.Hg + 2 H2O 2 NaOH + H2 + Hg This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  11 When the correct amount of water is used, 50% NaOH with a very low salt content (30 ppm) becomes the direct product with no evaporation required. The small loss of mercury to the environment presents extreme problems In the mercury-cell process, also known as the Castner–Kellner process, brine passes through a chamber which has a carbon electrode (the anode) suspended from the top. Mercury flows along the floor of this chamber and acts as the cathode. When an electric current is applied to the circuit, chloride ions in the electrolyte are oxidized to form chlorine gas. 2Cl-(aq) Cl2(g) + 2e- At the cathode, sodium ions are reduced to sodium. 2 Na+ ( aq ) + 2e- 2 Na ( Hg ) The sodium dissolves in the mercury, forming an amalgam of sodium and mercury. The amalgam is then poured into a separate vessel, where it decomposes into sodium and mercury. The sodium reacts with water in the vessel and produces sodium hydroxide (caustic soda) and hydrogen gas, while the mercury returns to the electrolytic cell to be used again. 2 Na ( Hg ) + 2H2O(l) 2 NaOH ( aq ) + H2(g) Figure 2.11 The mercury cell (Source: https://web.unep.org/globalmercurypartnership/our-work/mercury-cell-chlor- alkali-production) Some of the main problems with the mercury cell are as follows: This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  12 1. The reaction needs a higher voltage than the diaphragm cell: 4.5 V in the mercury cell compared to 3.5 in a diaphragm cell. 2. Requires quite a bit of electrical energy, as it needs 3400 kWh/ton Cl2 opposed to 2500 in a diaphragm cell. 2. Potential damage to the environment due to mercury deposits. Luckily deposits were as large as 200 g mercury per ton chlorine gas, but now, they never exceed 0.25 g per ton chlorine gas.Today, the brine is treated before it is discharged so that the environmental impact is lower. Mabuhay Vinyl Corporation is the only chlor-alkali producer in the Philippines. It is the country’s manufacturer of caustic soda and hydrochloric acid and the only company that produces chlorine in commercial quantities. A 26-hectare complex located at Assumption Heights, Buru-un, Iligan City, 9 km from the city proper and a kilometer from the jetty houses the two chlor-alkali plants. The plant employs the Ion Exchange Membrane Technology of Chlorine Engineers Corporation (Japan) for the brine electrolysis. Uses of Chlorine and Other Chlorine Products 1. Sodium Hydroxide Sodium Hydroxide is used for chemical manufacturing, pulp and paper industry, cleaning products, rayon and mercerized cotton industry, oil and gas treating industry. It is also used for degreasing metals, and also to remove sulphurous impurities from poor quality crude oil by a process called caustic washing. Figure 2.12 Some Applications of Caustic Soda (Source:https://www.21food.com/products/sodium-hydroxide---caustic-sod-2147107.html) This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  13 2. Chlorine Chlorine is used as a disinfectant, to treat drinking water and swimming pool water. It is also used to make hundreds of consumer products from paper to paints, and from textiles to insecticides. About 20% of chlorine produced is used to make PVC. This is a very versatile plastic used in window frames, car interiors, electrical wiring insulation, water pipes, blood bags and vinyl flooring. In organic chemistry, it is used as an oxidising agent and in substitution reactions. 85% of pharmaceuticals use chlorine or its compounds at some stage in their manufacture. Figure 2.13 Some Applications of Chlorine (Source:https://resources.schoolscience.co.uk/greenerindustry/pages/chlorine/1_chlori ne_ap.html) 3. Hydrogen Hydrogen is frequently made into other compounds, such as hydrochloric acid or ammonia, or is employed for the hydrogenation of organic compounds. It may also be burned for heat generation or used in a fuel cell to produce electricity. This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  14 Figure 2.14 Some Uses of Hydrogen (Source: https://www.controldron.com/drones-con-hidrogeno/usos-del-hidrogeno/ 4. Bleaching Powder Bleaching powder is used for bleaching dirty clothes in the laundry, as a bleaching agent for cotton and linen in the textile industry. It is also used as an oxidizer in many industries, and as a disinfectant which is used for disinfecting water to make potable water. Chlorine gas is used in the production of bleaching powder according to the reaction O Ca(OH)2 + Cl2 Ca. H2O Cl This reaction is carried out below 50OC in a countercurrent fashion by passing chlorine through a rotating steel cylinder with inner lifting blades which shower the solid through the path of the gas. The activity of bleaching powder is measured in terms of available chlorine.Available chlorine is the weight of chlorine that would exert the same action as the chlorine compound in question. For bleaching powder, the available chlorine is the same as the percentage chlorine. It contains about 35% or less of available chlorine when freshly manufactured. This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  15 Figure 2.15 Bleaching Powder (Source:https://zychemical.en.made-in-china.com/product/yMSxrqOPLNUD/China- High-Chlorine-Bleaching-Powder-Factory-Calcium-Hypochlorite-Cl-28-70-.html) 5. Calcium Hypochlorite Calcium hypochlorite is a good oxidizing agent and is used in the field of organic chemistry. It is used to obtain fragmented aldehydes/carboxylic acids by cleaving the bonds in glycols and keto acids. Ca(ClO)2 can also be used in the halo form reaction to yield chloroform. The compound can be used to disinfect both wastewater and drinking water since it has a high chlorine availability. Calcium hypochlorite is manufactured by the formation under refrigeration of the salt [Ca(OCl)2.NaOCl.NaCl.12H2O], which is prepared by the chlorination of a mixture of sodium and calcium hydroxides. This is reacted with a chlorinated lime slurry, filtered to remove salt, and dried, resulting finally in a stable product containing 65-70%. The reaction is Ca(OCl)2.NaOCl.NaCl.12H2O + CaCl2 + Ca(OCl)2 4 Ca(OCl)2.2H2O + 4 NaCl + 16 H2O Calcium hypochlorite is twice as strong as ordinary bleaching powder, and for calcium hypochlorite, available chlorine is twice the percentage (49.65) of chlorine present (99.2%)Ca(OCl)2. This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  16 Figure 2.16 Some Uses of Calcium Hypochlorite (Source: https://www.alibaba.com/product-detail/35-bleaching-powder-70-chlorine- bleaching_62006006458.html) 6. Sodium Hypochlorite Sodium hypochlorite is used as a key ingredient in laundry bleach, as a bleaching agent, in textile industries, as an oxidizing agent, in detergent industries, in the refining of petroleum products, in paper industries, in wastewater treatment, as a disinfectant, in food processing to sanitize the food preparation equipment, in swimming pools to keep the infectious agents at bay. The most common method for making it is the treatment of sodium hydroxide solution with gaseous chlorine. Cl2 + 2NaOH NaCl + H2O + NaOCl Figure 2.17 A Bottle of Sodium Hypochlorite (Source: https://www.chemtex.shop/product/chemtex-sodium-hypochlorite-solution/) This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  17 7. Sodium Chlorite Sodium chlorite is used in the industry as bleaching agents, finishing agents, in the final whitening of kraft paper in the pulp and textile industry, intermediates, oxidizing/reducing agents, plating agents and surface treating agents, in water treatment products, and as processing aids, specific to petroleum production. Sodium chlorite is manufactured from chlorine through calcium chlorate to chlorine dioxide, ending with the reaction 4NaOH + Ca(OH)2 + C + 4 ClO2 4 NaClO2 + CaCO3 + 3 H2O Figure 2.18 A Bottle of Sodium Chlorite (Source: https://en.wikipedia.org/wiki/Sodium_chlorite) PROGRESS CHECK (To be posted on GC) REFERENCES Books Shreve's chemical process industries. (1984). On-Line Sources Calcium hypochlorite [Ca(ClO)2] - Structure, properties & uses. (2019, February 11). BYJUS. https://byjus.com/chemistry/calcium-hypochlorite/ Chemical name of bleaching powder - Preparation, formula, videos & uses. (2017, October 31). BYJUS. https://byjus.com/chemistry/bleaching-powder-and-sodium-hydroxide/ This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  18 Chlorine - Element information, properties and uses | Periodic table. (n.d.). The Royal Society of Chemistry. https://www.rsc.org/periodic-table/element/17/chlorine#: Facilities. (2018, October 26). Mabuhay Vinyl Corporation. https://www.mvc.com.ph/about- us/facilities/ The major applications of sodium carbonate or "Soda ash". (n.d.). Blog. https://sodis- plc.com/blog/en/the-major-applications-of-sodium-carbonate-or-soda-ash/ Sodium bicarbonate, production, history and uses. (n.d.). ILNA. https://www.ilna.news/Section-economy-4/1062921-sodium-bicarbonate- production-history-and-uses OpenStax CNX. (n.d.). OpenStax CNX. https://cnx.org/contents/[email protected]:qnFQr_g2@1/The-chloralkali- industry Sodium hypochlorite (NaClO) - Structure, molecular mass, properties & uses. (2018, September 25). BYJUS. https://byjus.com/chemistry/sodium-hypochlorite-bleach/ The facts about chlorine. (n.d.). New York State Department of Health. https://www.health.ny.gov/environmental/emergency/chemical_terrorism/chlo rine_general.htm Usos del Hidrogeno » control DRON. (2019, September 23). CONTROL DRON. https://www.controldron.com/drones-con-hidrogeno/usos-del-hidrogeno/ ------------------------------------------------------------------------------------------------------------ This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.