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Definition
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| the link joining two cyclic sugars is called ___, ___, and ___ |
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Definition
acetal linkage
saccharide linkage
glycoside linkage |
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Definition
| enhances the rate of the rxn without being consumed or permanently altered |
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Term
| catalysts usually work by... |
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Definition
| ...reducing activation energy, usually by providing a different rxn mechanism |
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Definition
| kinetics, not thermodynamics, so they can't change the position of equilibrium, only help to get there faster |
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Definition
1. in the same phase as reactants and products
2. no problem getting the reactants to the catalyst, but at the end, you have to separate them
3. biochemical rxns (enzymes) |
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Definition
1. in a different phase than the reactants and products
2. trouble getting the reactants to the catalyst, but at the end, separation needed
3. industrial rxns |
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Definition
1*: sequence of amino acids
2*: alpha coils and beta pleats
3*: 3-D conformation
4*: multiple proteins joined together |
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Definition
1. activity- how fast it works
2. turnover frequency- (# of rxns per catalyst site)/time
3. selectivity- (desired product)/(all products) |
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Term
| homogeneous vs. heterogeneous catalysts |
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Definition
| homogeneous catalysts (enzymes) have very high turnover frequency (~1000/sec) and good selectivity (~100%) |
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Term
| CONVERSION OF POLYSACCHARIDES TO ETHANOL |
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Definition
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Definition
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Definition
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| ethanol fermentation details |
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Definition
catalyst is yeast
max ethanol conc. is 8-12%, because above that, the alcohol kills the yeast
after that, distillation is used to increase the concentration |
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Term
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Definition
| 1. use directly as fuel (slight energy penalty because of the 5% water) 2. make 100% ethanol by A. add a third component like benzene to shift the equilibrium B. react the water away C. cleverly separate the ethanol and water (membranes, etc.) |
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Definition
| theoretically CO2 neutral |
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Definition
principally renewable
(concerns: soil depletion and monoculture dependence) |
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Definition
| secure, domestic energy resource |
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Definition
| very high octane number--suitable for high compression engines |
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Definition
| partially oxygenated -> shifts combustion chemistry in the engine to reduce emissions of CO and unburned fuel |
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Definition
| infinitely miscible with water |
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Definition
| lower volumetric energy density than gasoline (lower MPG) |
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Definition
materials compatibility--ethanol is an alcohol (gasoline is a hydrocarbon) -> different interactions with parts of the fuel system
(not a big deal--largely solveable) |
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Definition
| food vs. fuel argument--is it ethical? |
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Definition
low energy balance--1.5 (compared to gasoline's 20)
waste of energy is due to distillation (water has a high specific heat) |
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Definition
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| (energy liberated by burning)/(energy used to make) |
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Definition
1. find hardy plants (low-maintenance, grow on crappy soil)
2. find easy hydrolysis of cellulose at mild conditions
3. find yeast that can tolerate >12% ethanol
4. find low energy separation processes (so that we don't have to use distillation) |
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Definition
| long-term energy storage for plants |
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Term
| plant oil/biodiesel con #1 |
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Definition
high molecular wt
-> low vapor pressure
-> hard to vaporize for combustion
-> hard to use in cold weather |
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Term
| plant oil/biodiesel con #2 |
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Definition
high viscosity
(and viscosity increases as temp. decreases) |
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Term
| plant oil/biodiesel con #3 |
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Definition
| oil molecules tangle with each other and form gums in the engine |
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Term
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Definition
derived from petroleum;
made of alkanes 12-20 carbons long |
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Definition
| take apart the plant oil molecule to get the carbon chains |
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Definition
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Term
| ester hydrolysis of plant oil to get the carbon chains can be ___ or ___ |
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Definition
base induced (not a catalyst)
acid catalyzed |
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Term
| base-induced hydrolsis is used over acid-catalyzed hydrolysis for plant oils because... |
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Definition
| ...the last step of the base-induced rxn is a forward-only rxn |
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Term
| the RCOO- formed in base-induced hydrolysis is acidic and bad for the engine, so... |
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Definition
| ...it is re-sterified, but with the smallest alcohol, methanol |
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Term
| biodiesel vs. petrodiesel |
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Definition
biodiesel has no sulfur and no aromatic compounds -> very clean burning
the couple of oxygens in biodiesel give a small energy penalty |
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Term
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Definition
biodiesel is much easier to make
but we need to figure out what to do with the glycerol that forms
we also need a plant oil source |
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Term
| plant oil/biodiesel pro #1 |
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Definition
| easy to make compared to ethanol |
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Term
| plant oil/biodiesel pro #2 |
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Definition
| more clean-burning than petrodiesel |
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Term
| plant oil/biodiesel pro #3 |
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Definition
| it can be used in a petrodiesel engine |
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Term
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Definition
| plant oil + methanol -> 3 FAs + glycerol |
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Definition
| use of thermal energy to split molecules |
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Term
| pyrolysis is also called ___ and ___ |
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Definition
thermal decomposition
carbonization |
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Term
| why does charcoal have a higher calorific value than wood? |
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Definition
| wood is 35-45% oxygen (it's already partially oxidized, so there's less to oxidize/burn), while charcoal has most of the oxygen already gone |
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Term
| products of wood pyrolysis |
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Definition
gas: CO2, CO, CH4, small hydrocarbons
liquid: pyroligneous acid |
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Term
| hardwood pyroligneous acid |
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Definition
aqueous phase: methanol, acetic acid, acetone
heavy organic phase |
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Term
| softwood pyroligneous acid |
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Definition
light organic phase: turpentine, pine oil
aqueous phase: methanol, acetic acid, acetone
heavy organic phase: wood creosote |
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Term
| methanol can be made from wood by ___ and ___ |
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Definition
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Term
| wood -gasification-> methanol |
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Definition
1. endothermic, so the heat from combustion rxn is used to power it
2. product is synthesis gas (CO and H2), which can be made into methanol
3. 90% yield of methanol |
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Definition
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| wood -pyrolysis-> methanol |
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Definition
1. endothermic, so the heat from combustion rxn is used to power it
2. methanol is separated out from the organic and aqueous phases
3. 2% yield of methanol |
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