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Chemical Manufacturing

Chemical Manufacturing. By: Robert McVicar & Brenna Lindsey-Swecker. CHEMICAL MANUFACTURING: 1 Raw materials from environment to industry and consumer useful products *Commodity = Large quantities, single chemical *Specialty = Small scale, “made to order”.

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Chemical Manufacturing

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  1. Chemical Manufacturing By: Robert McVicar & Brenna Lindsey-Swecker

  2. CHEMICAL MANUFACTURING: 1Raw materials from environment to industry and consumer useful products *Commodity = Large quantities, single chemical *Specialty = Small scale, “made to order” 2The Chemical Industry is a principle contributor to the US economy • Main customers of chemical manufacturers are: • Auto industry • Agricultural industry • Housing industry, and • Product manufacturing industry 2Environment: Industry emits more than 1.5 million tons of categorized air pollutants

  3. Sulfuric Acid 3The Most Important Chemical • Has been manufactured for more than 400 years • 150 million tons of sulfuric acid is produced annually • A nation’s level of sulfur production can be used to indicate the nation’s industrial compactly. • Surprisingly inexpensive ($150/ton) • Each step is an exothermic process • Heat is sold as energy • Average daily production of sulfuric acid produces 7x106 watts of electric power.

  4. Uses of Sulfuric Acid Amazing number of applications…

  5. Sulfuric Acid Production Process 1. Obtaining sulfur: modern contactprocess is used. • Claus process utilized: H2S in natural gas is chemically separated then oxidized: • 2H2S(g)+2O2(g) 1/2S8(g)+SO2+2H2O(g) • 2H2S(g)+SO2(g)  3/8S8(g)+2H2O(g)

  6. Sulfuric Acid Production Process • When natural gas is not readily available but there are natural underground deposits the Frasch process is utilized: • A hole is drilled, superheated water melts the sulfur. • A combination of hydrostatic pressure and the pressure of condensed air force the sulfur to the surface. • Produces a very pure substance.

  7. Sulfuric Acid Production Process 2. From sulfur to sulfur dioxide. • Sulfur is burned in air to obtain SO2 • 1/8S8(s) + O2(g)  SO2(g) • ΔH° = -297 kJ

  8. Sulfuric Acid Production Process 3. From sulfur dioxide to trioxide: the contact process oxidizes SO2 with O2 to form SO3 • SO2(g) + 1/2O2 SO3(g) ΔH° = -99 kJ • Reaction is exothermic and occurs very slowly at room temperature.

  9. Sulfuric Acid Production Process • Le Chatelier’s principle plays major role in third step.

  10. Sulfuric Acid Production Process 4. From sulfur trioxide to acid • First a hydration step: SO3(g) + H2O(l) H2SO4(l) SO3(g) + H2SO4(l)  H2S2O7(l) H2S2O7(l) + H2O(l)  2H2SO4(l)

  11. Chlorine Ranked in top ten chemicals produced in the United States • 4Used in over 50 percent of all industrial chemical processes: • 90 percent of pharmaceuticals • 96 percent of crop protection chemicals. http://www4.uwm.edu/shwec/publications/newsletters/pills.jpg http://www.ism.ws/pubs/EmailNewsletters/ChemicalsNewsletter/eDigestChemicalDetail.cfm?ItemNumber=4640

  12. Chlorine • The chlor-alkali process electrolyzes NaCl(aq) to produce Cl2 • (and other important chemicals) • Asbestos Diaphragm • Mercury-Cell • Membrane-Cell Electrolysis Plant http://www.bayertechnology.com/uploads/pics/chlorine_electrolysis_references_01.jpg

  13. Chlor-alkali Process Anode: Cl- oxidixed Cathode: H20 reduced Half-Reaction 2Cl-(aq)  Cl2(g) + 2e- Eo = 1.36v 2 H20 + 2e-2OH-(aq) + H2(g) Eo = -1.0v Total Ionic 2Na+(aq) + 2Cl-(aq) + 2 H20  2Na+(aq) + 2OH-(aq) + H2(g) + Cl2(g) Cathode compartment is a mix of NaCl and NaOH - NaCl removed by fractional crystallization Electolysis of NaCl salt yields Cl2, H2 and NaOH http://pia.khe.siemens.com/bilder/pi2_internet/branchenloesungen/chlor_alkali_e.jpg

  14. Chlor-alkali Process Asbestos Diaphragm Diaphragm separates half cell compartments * Cl2 and H2 kept apart to prevent explosive combination

  15. Chlor-alkali Process Mercury-Cell http://www.geneticmaize.com/2009/02/whats-in-the-corn-syrup-guest-post-by-renee-dufault/ Mercury replaced at cathode(favors Na+ reduction) 2Cl-(aq)  Cl2(g) + 2e- 2Na+(aq) + 2e-+Hg 2Na(Hg) Sodium Amalgam treated with water 2Na(Hg) + 2 H20 -Hg 2Na+(aq) + 2OH-(aq) + H2(g) Being phased out due to water contamination - 200 g Hg per ton of Cl2 produced!

  16. Cl- removed at anode to form Cl2 Na+ ions travel through membrane to cathode Na+ ions form NaOH Chlor-alkali Process Membrane-Cell Replaces Diaphragm with polymeric membrane - Allows cations to move through *Uses less electricity and purity of NaOH greater

  17. Information References 1http://www.libraries.psu.edu/psul/business/industry_guides/ chemical.htm 2http://www.epa.gov/ispd/chemical/index.html 3Chemistry Textbook 4http://worldchlorine.com/products/index.html

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