Post on 15-Dec-2015
transcript
1
Green Chemistry Across the CurriculumAt St. Olaf College
Bob HansonBCCE20, Indiana University, July 28, 2008
A Project Supported By the W.M. Keck Foundation
2
Goals of Green Chemistry at St. Olaf
• Alter the chemistry curriculum 1st year, 2nd year, 3rd year
• Design a science facility that reflects this effort LEED Gold Building www.stolaf.edu/sciencecomplex/
3
Web App: Green Chemistry Assistant http://fusion.stolaf.edu/gca
A collaborative project between St. Olaf College and US EPA - an extension of the EPA Green Chemistry Expert System SMART module
4
Wittig ReactionAtom Economy – 30.3%E-Factor – 58.5 : 1
Ring Closing Metathesis of Diethyl Diallylmalonate Atom Economy – 88.3% E-Factor – 25.5 : 1
Desired Product
Coproduct
Catalysts
Solvents
Other materials
GCA Graphical Output
5
GCA graphics
6
GCA graphics
7
1st Year: Periodic Trends & Solubility
• Lab Manual includes “Green Connections” and new pre-/post-lab questions
• Replace heptane with ethyl acetate Volatile but with lesser hazards Option as a renewable resources Potentially less harmful degradation
products• Observed color differences
Chlorine: colorless, Bromine: orange, and Iodine: yellow
• Replace chromate anion with thiosulfate anion and eliminate barium cation
Heptane EtOAc
Cl2
Br2
I2
8
1st Year Experimental Changes
Ethanol oxidation: kinetics study• Eliminate the chromate oxidation
process. • Uses household bleach (6%
sodium hypochlorite solution) • Eliminates concentrated
hydrochloric acid
Mystery Product Reactions• Replace permanganate with
iodine redox system• Eliminates phosphoric and
hydrochloric acids• 70% waste reduction (30 L
annually)
7 experiments revised & changes implemented
9CuCl2·2H2O CuCl2
10
1st Year Waste Management Introduction
Efforts:
• Students typically work in groups of two or three.
• Each group is required to appoint one student who will take responsible for accounting for group waste and filling out “waste manifests” for their group.
Results (unquantified):
• Students are far more aware of waste issues.
• Students like taking some responsibility in this regard.
• Faculty become more aware of waste issues as well.
• Safety discussions and awareness arise spontaneously.
11
2nd Year: Sonogashira Coupling Reaction
CH3
O
+ +Methanol, Water
KI KIO3
HCl, 25O C, 20 hours
I
CH3
O
Figure 1: Iodination of anisole
I
CH3
O
OH
CH3
CH3
CH
OH
CH3CH3
CH3
O
PEG, Triethylamine
PdCl2(PPh3)2, CuI, Heat
Figure 2: Sonogashira reaction with 2-methyl-3-butyn-2-ol
+
Palladium (5%) and copper (8%) catalyzed coupling of terminal alkynes with aryl halides
Uses product made in 1st lab of second semester,
PEG 200 solvent
Microwave 1 minute at 240 Watts
Moderate success recycling catalysts and PEG solvent
20+ experiments evaluated and 7 changed
12
More 2nd Year Experimental Pursuits
• Ring Closing Metathesis Catalytic ring closure with
production of ethylene Microwave for heating …
proceeded to 98.3% conversion
• Polyethylene glycol solvent potential to recycle the
catalyst low toxicity, biodegradability,
and low vapor pressure modest catalyst recycling
success
EtO OEt
O OOO
EtO OEt
CH2 CH2
+
1 .0 m m ol
CH2
CH2
6 .5 % m o l G ru b b s C a ta lys t
.5 m L P E G , m ic ro w a v e h e a t in g
13
3rd Year: Goals & Objectives
• Infuse Analytical & Physical labs with green chemistry principles
• Develop appropriate metrics
• Test metrics and apply to current lab experiments (benchmarking)
• Determine labs with the least green characteristics NFPA 3 High material/solvent use High energy use Nonrenewable feedstocks Stoichiometric reactions
• Reduce waste stream
• Develop new or modified experiments Change chemistry or
chemical system Reducing material/solvent
use in currents labs Make volumetric reductions Analysis of citrus fruit
essential oils by GC, GC/MS, Raman and/or IR-ATR.
14
Analytical Lab BenchmarksLab Topics NFPA 3 Solvent Use Waste/Group
Glassware Calibration
Cleaning &Stats EtOH-KOH H2O (2 L) Neutralized - Sewer
CaOxalate Gravimetry & AAS HCl H2O (17.4 L) 1.04 L
low pH
Weak Acid Titrations NaOH H2O (4.5 L) Neutralized – Sewer
MockRobot IsosPt & Automat. H2SO4, NaOH H2O (2.1 L) Neutralized – Sewer
Easter Egg Grass
Food dyes UV/VIS - H2O (3 L) Neutralized – Sewer
Downsizing Fe-bipy, UV/VIS & Automation
HCl, NH2OH•HCl
H2O (3 L) 1.31 L
Metals
Broken Pill Machine
Metals & AAS HCl, HNO3, Bronze alloys
H2O (4 L) 1.18 L, low pH Metals
Mysterious Death
Chromatogr. & HPLC
MeOH, Acetic Acid, Et3N
Mobile Phase Volume
0.32 L
low pH
15
3rd Year: Solvent Reduction - HPLC
Discovery HS C18 75 x 3 mm (3.5 m dp), 20 L inj, 254 nm detection; 68:30:1.5:0.5 Water:MeOH:formic acid:triethylamine; 0.50 mL/min. Analytes: a) procainamide, b) qunidine, c) lidocaine, d) diisopyramide.
-6.0
-4.0
-2.0
0.0
2.0
0 2 4 6 8 10
Minutes
Sig
na
l
Mixed Flow 0.5Original
dc
b
a
a
c
d
b
*
75% solvent reduction, 50% time reduction
16
Analytical MetricsMetric Name Measures efficiency of Formula
Analytical Atom Economy AAE
Transformation of reactant atoms into a desired product necessary to prepare the analyte for analysis.
Analytical Mass Efficiency AME
Chemical and solvent use involved in a chemicalreaction.
Method Mass Efficiency MME
Comprehensive material use necessary for entire analysis method.
Energy per Analytical Unit EPAU
Energy use for entire analysis method relative to the mass of analyte in sample.
100 x Reagents ofFW
Analyte ofFW AAE
100 x )Solvents(g Reagents, ofFW
Analyte(g) of MassAME
100 x
(g) Prep Cleaning,
Solvents, Reagents, ofFW
(g) Analyte of MassMME
100 x (g) analyte of Mass
(kJ)energy method TotalEPAU
17
3rd Year: Volumetric Reduction - Downsizing
• Iron determination via bipyridine complexation
• Automation (robotic) vs. human (volumetric) method.
• Challenge – maintain # sig figs and solution handling.
Starting Materials Original Amount
Modified Amount
iron wire 25 mg 10 mg
HCl, conc. 10 mL 8 mL
HCl, 0.2M 35 mL 17.5 mL
hydroxylamine hydrochloride, 10%
35 mL 17.5 mL
Na acetate, 2 M 14 mL 7 mL
bipyridine, 0.1% 70 mL 35 mL
water 1031 mL 511.5 mL
AAE 79.87% 79.87%
AME 1.67x10-5% 3.34x10-5%
MME 4.77x10-6% 9.53x10-6%
18
3rd Year: New Citrus Oil Analysis
SAMPLING STRATEGIES
• Solid Phase Microextraction Peel / zest into vial PMDS-DVB fiber
• Supercritical CO2 extraction
Peel / zest into centrifuge tube Dry ice & water bath
Why is lemon oil used for some consumer products and orange oil for others? How chemically similar are citrus oil extracts? How would you determine this when starting with a piece of fruit (grapefruit, lemon, lime, or orange) and doing as little sample preparation as possible?.
19
Physical Properties of CO2
CO2 (l) Good solvent for small, nonpolar molecules: hydrocarbons < 20 carbon atoms & some aldehydes, esters, and ketones
20
Headspace Samples of Citrus ZestHeadspace Samples of Citrus Zestings
0
7 7.5 8 8.5 9 9.5 10 10.5 11
Minutes
Inte
nsity
Limonene
-Pinene-Pinene -Terpinene
GC Conditions: VF-5 capillary column (30 m x 0.25 mm x 0.23 m film), splitless inj 250 °C; column oven hold 50 °C 1 min, 10 °C/min, hold 240 °C for 10 min; helium carrier gas 30 cm/s. MS Conditions: EI, Full scan 40-350 m/z. SPME: PDMS-DVB fiber, 65 m, 30 s retracted headspace exposure.
Grapefruit
Lemon
Lime
Orange
21
New Science Facility Sept. 1, 2008 Opening
• Interdisciplinary• Investigative• Interactive• Innovative• Interconnected• Inviting • Integrity
Green Team, Builder (Boldt), Architect (Holabird & Root)
LEED Gold target Building as Teacher Life-cycle costs Chemical Fume Hood
Reductions (energy, operations, first costs)
• 120,000 NASF, 26 teaching labs• Informal gathering spaces
designed to extend learning beyond the classroom and laboratory. Green roof terrace Adjacent landscape Water management basins
65% decrease for intro/2nd year chemistry (2.5 linear ft/student std)40% decrease across facility compared to initial design
22
Future/On-going Work
• Continue development and implementation in first two years of curriculum, particularly in the area of waste management and safety
• Ramp up development and implementation in third year of curriculumPiloting upper level p-chem lab (aqueous SEC
w/proteins & dextrans to calculate virial coefficients)• LEED-NC Innovation Credit – Green Chemistry & Hood
Reduction• Hire another Post-Doc (Enquire here!)