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Gary Bonomo
General Chemistry Lab Instructor and Supervisor Syracuse University Chemistry Department
(Syracuse University Chemistry Department Home Page, 2015)
CHE 107: General Chemistry Laboratory I ! Lab 03: Preparation and Viscosity of Biodiesel from Vegetable Oil ! Lab 05a: Chemistry of Recycling Aluminum ! Lab 05b: Synthesis of Alum from Clay
CHE 117: General Chemistry Laboratory II ! Lab 03: Vitamin C Clock Reaction
(Microsoft Office Clip Art, 2013)
Original Lab Provided by SUNY ESF
! Preparation and Viscosity of Biodiesel from Vegetable Oil (Abrams, 2007; adapted from Clark et al., 2006)
! Permission granted to use this lab at Syracuse University
Modifications at Syracuse University
! Separation method of biodiesel and glycerol
! Relative Viscosity – modified to reuse same chemical reagents (less waste)
! Biodiesel product is used at Syracuse University
Biodiesel Synthesis
! Combine KOH pellets and methanol to make potassium methoxide KOH (s) + CH3OH (l) ! K+
(aq) + CH3O– (aq) + H2O (l)
! Put canola oil in a beaker and heat in a water bath (50 °C)
! Add potassium methoxide solution to canola and bring temperature of water bath to 65-70 °C (maintain temperature and stir for 45 minutes)
Triglyceride + 3 CH3O– ! 3 Biodiesel (Methyl Esters) + Glycerol
! Cool solution and use a separatory funnel to separate glycerol and biodiesel
(Abrams, 2007; adapted from Clark et al., 2006)
Relative Viscosity
! Four samples tested: " B100 (100% biodiesel) at room temperature " B100 (100% biodiesel) at ice bath temperature " B20 (20% biodiesel, 80% petroleum diesel) at room temperature " B20 (20% biodiesel, 80% petroleum diesel) at ice bath temperature
! Fill a 25 mL pipette above the 0 mL mark. Begin draining and time from the 0 mL mark to the 23 mL mark. Drain back into sample container.
! Determine the relative viscosities by the following equation: Relative Viscosity = Sample Time / B100 Room Temperature Time
(Abrams, 2007; adapted from Clark et al., 2006)
Biodiesel Synthesis
! How to prepare biodiesel fuel by transesterification
! Biodiesel is green alternative to fossil fuels
Relative Viscosity of Biodiesel
! How to calculate relative viscosity
! High viscosity and solidification of biodiesel at low temperatures
! B20 is a better alternative than B100 in cold climates
(Abrams, 2007; adapted from Clark et al., 2006)
First Part from SUNY ESF (Abrams, 2007)
! Students recycled aluminum to produce hydrogen gas (H2) and KAl(SO4)2•12H2O (crystals of potassium alum)
Second Part at Syracuse University (Miller, 2013)
! Kaolin clay produces alum less expensively than starting from scrap Al
! Halloysite Nanoclay (H4Al2O9Si2 • 2 H2O) is used instead of Kaolin (Al2Si2O5(OH)4), to avoid calcination of clay and sulfuric acid***
*** This is a safety choice for the classroom setting; still similar chemistry to the industrial process except with less heat and high cost clay
! Examine alternative recycling methods for aluminum instead of conversion to alum (melt and forge into a new aluminum metal application)
Preparation
! Sample of aluminum foil is cutting into pieces (Al with polymer coating)
Forming K[Al(OH)4]
! 3M KOH and light heating converts aluminum foil to K[Al(OH)4] 2 Al (s) + 2 KOH (aq) + 6 H2O (l) ! 2 K[Al(OH)4] (aq) + 3 H2 (g)
! Gravity filtration removes residual polymer coating
(Abrams, 2007)
Forming Soluble Al2(SO4)3
! 9 M H2SO4 added to form precipitate of aluminum hydroxide Al(OH)3 2 K[Al(OH)4] (aq) + H2SO4 (aq) ! 2 Al(OH)3 (s) + 2 H2O (l) + K2SO4 (aq)
! Sulfuric acid dissolves Al(OH)3 to form soluble Al2(SO4)3 2 Al(OH)3 (s) + 3 H2SO4 (aq) ! 2 Al2(SO4)3 (aq) + 6 H2O (l)
Forming Alum Crystals
! Heat to dissolve; then cool in an ice bath and add a seed crystal: Al2(SO4)3 (aq) + K2SO4 (aq) + 24 H2O (l) ! 2 KAl(SO4)2 • 12 H2O (s)
! Vacuum filter to separate, using 50 % ethanol to rinse
(Abrams, 2007)
Summary of Chemical Reactions:
2 Al (s) + 2 KOH (aq) + 6 H2O (l) ! 2 K[Al(OH)4] (aq) + 3 H2 (g)
2 K[Al(OH)4] (aq) + H2SO4 (aq) ! 2 Al(OH)3 (s) + 2 H2O (l) + K2SO4 (aq)
2 Al(OH)3 (s) + 3 H2SO4 (aq) ! 2 Al2(SO4)3 (aq) + 6 H2O (l)
Al2(SO4)3 (aq) + K2SO4 (aq) + 24 H2O (l) ! 2 KAl(SO4)2 • 12 H2O (s)
----------------------------------------------------------------------------------------------------------------------------------------------------------
2 Al (s) + 2 KOH (aq) + 4 H2SO4 (aq) + 22 H2O (l) ! 2 KAl(SO4)2 • 12 H2O (s) + 3 H2 (g)
(Abrams, 2007)
(Miller, 2013)
Forming Soluble Al2(SO4)3
! Add 5 M H2SO4 to clay, stir for 5 minutes, and store for 1 week H4Al2O9Si2 • 2 H2O (s) + 3 H2SO4 (aq) ! Al2(SO4)3 (aq) + 2 SiO2 (s) + 7 H2O (l)
! Gravity filtration removes the silicon dioxide
Forming Alum Crystals
! Add K2SO4 and heat until the solution is boiling
! Cool in an ice bath and add a seed crystal: Al2(SO4)3 (aq) + K2SO4 (aq) + 24 H2O (l) ! 2 KAl(SO4)2 • 12 H2O (s)
! Vacuum filter to separate, using 50 % Ethanol to rinse
(Miller, 2013)
Summary of Chemical Reactions:
H4Al2O9Si2 • 2 H2O (s) + 3 H2SO4 (aq) ! Al2(SO4)3 (aq) + 2 SiO2 (s) + 7 H2O (l)
Al2(SO4)3 (aq) + K2SO4 (aq) + 24 H2O (l) ! 2 KAl(SO4)2 • 12 H2O (s)
-------------------------------------------------------------------------------------------------------------------------------------------------------------
H4Al2O9Si2 • 2 H2O (s) + 3 H2SO4 (aq) + K2SO4 (aq) + 17 H2O (l) ! 2 KAl(SO4)2 • 12 H2O (s)
Green Chemistry
! Comparison of methods for alum production: Starting with scarp aluminum metal vs. Starting from Clay
! Comparison of methods for aluminum metal: Melting of scarp aluminum metal vs. electrolysis of aluminum oxide
Lab Techniques and Calculations
! Gravity filtration and vacuum filtration
! Supersaturation and crystallization
! Limiting reagent, theoretical yield, and percent yield
(Abrams, 2007) and (Miller, 2013)
Green Chemistry in Higher Education Workshop
! Hosted July 2013 by beyondbenign
! Getting off to a good start: Using safer starting martials (King, 2010; adapted from Wright, 2002)
! Produced a small amount of waste and low hazard waste
! Light on calculations, but explained general concept
Existing Lab in 2013
! Reaction Kinetics and Effect of Temperature (Luk, 2009)
! Produced a lot of waste and somewhat hazardous waste
! Detailed calculations, expand on the depth of the concept
Merging and Modifying of the Labs (Zheng, 2013)
! Cost savings in materials and smaller amount of waste generated
! Kept the detailed calculations and in depth data analysis
Article from beyondbenign (Cannon, 2015)
! Detailed case study highlighting the cost savings and waste reduction between the 2009 lab (Luk) and the 2013 lab (Zheng)
! Waste disposal costs reduced from $333.05 to $82.25 per 500 students Waste Disposal Cost Savings of $250.80 per 500 students
! Purchasing costs reduced from $977.30 to $136.00 per 500 students Purchasing Cost Savings of $841.30 per 500 students
Solutions
! Beaker 1: Potassium iodide, starch, and sodium thiosulfate potassium nitrate and ammonium sulfate used for dilutions rather than DI Water to keep the same spectator ion concentrations (K+ and NH4
+)
! Beaker 2: Ammonium persulfate
! Combine Beakers 1 and 2; stir and record time for the color to change
Concentration and Temperature
! Vary concentration of I– and S2O82–
! Vary temperature (ice bath, room temperature, hot water bath)
(Luk, 2009)
(Luk, 2009)
Run 3 is repeated in ice bath and hot water bath
Three Trials per each Run (15 Trials total)
Notable PostLab Questions
! Calculate the concentrations of the reactants when combined
! Calculate the reaction rates, orders of reaction, and rate law
! Calculate the rate constants for each trials
! For the three different temperature trials, graph ln k vs 1 / T
! Use the slope from the graph (– Ea / R) to determine the activation energy
(Luk, 2009)
Solutions
! Vitamin C solution: Vitamin C tablet dissolved in DI water with mild heating and gravity filter to remove insoluble materials
! Solution A: Vitamin C solution, Lugol’s Iodine and DI water
! Solution B: hydrogen peroxide and liquid laundry starch
! Combine Solutions A and B; stir and record time for the color to change
Concentration and Temperature
! Vary concentration of hydrogen peroxide and Lugol’s Iodine
! Vary temperature (ice bath, room temperature, hot water bath)
(Zheng, 2013)
(Zheng, 2013)
Trial 1 is repeated in ice bath and hot water bath
One Trial per each Run (5 Trials total)
Notable PostLab Questions
! Calculate the concentrations of the reactants when combined
! Calculate the reaction rates, orders of reaction, and rate law
! Calculate the rate constants for each trial
! For the three different temperature trials, graph ln k vs 1 / T
! Use the slope from the graph (– Ea / R) to determine the activation energy
! Look up the procedure for the “Old Nassau Reaction” and compare the procedure of this lab. Which is greener and why?
(Zheng, 2013)
Reagents:
! Do you have hazardous regents that have safer alternatives?
! Do have any unnecessary reagents?
! Can any reagents and supplies be used more efficiently?
Waste:
! Keep different wastes separate waste; easier for treatment later.
! Can any of the products be used by your lab or someone else?
! Collaborate with your school’s waste collection and processing staff!
Curriculum:
! Can any concepts be taught better through the lens of Green Chemistry?
1. Syracuse University Chemistry Department Home Page. http://www-che.syr.edu/ (accessed June 8, 2015).
2. SU Photo & Imaging, as cited by Syracuse University Archives. http://www-che.syr.edu/ (accessed June 8, 2015).
3. Office.com Clip Art. Microsoft PowerPoint (Version 2013). Microsoft Corporation.
4. Abrams, N. Preparation and Viscosity of Biodiesel from Vegetable Oil. SUNY ESF, 2007. *Adapted from: Clark et. Al, 2006, J. Chem. Ed., 83 (2), 257-259.
5. Abrams, N. Chemistry of Recycling Aluminum. SUNY ESF, 2007.
6. Miller, C. Synthesis of Alum from Clay. Syracuse University, 2013.
7. King, J. Getting off to a safe start: Using safer starting materials for chemical reactions. Intro to Green Chemistry. 2010. *Adapted from: Wright S., 2002, J. Chem. Ed., 79 (1), 41-43.
8. Luk, Y. Reaction Kinetics and Effect on Temperature. General Chemisty Laboratory II CHE 117 Lab Manual; Second Revised Printing. Kendall Hunt Publishing. Syracuse University, 2009.
9. Zheng, H. Vitamin C Clock Reaction. Syracuse University, 2013.
10. Cannon, A. Vitamin C Clock Reaction, beyondbenign, 2015. *Adapted from: “Getting off to a safe start – Using safer starting materials for chemical reactions” in Introduction to Green Chemistry: Instructional Activities for Introductory Chemistry, ACS, 2002.