chemical synthesis Flashcards
haber process
N₂ + 3H₂ ⇌ 2NH₃ + ΔH
Fe₃O₄/450-500°C/150-200atm
contact process
2S + 3O₂ + 2H₂O ⇌ 2H₂SO₄ + ΔH
V₂O₅/400-450°C/1-2atm/O₂ in 1:1 ratio
base-catalyzed transesterification of triglycerides into biodiesel
triglyceride + 3CH₃OH → glycerol + 3 fatty acid-COOCH₃ (biodiesel)
(NaOH)
lipase-catalyzed transesterification of triglycerides into biodiesel
triglyceride + 3CH₃OH → glycerol + 3 fatty acid-COOCH₃ (biodiesel)
(lipase)
advantages & disadvantages of base-catalyzed transesterification
advantages : high yield; fast rate of reaction; cheap catalyst
disadvantages : high energy consumption; soap byproduct; low product purity
advantages & disadvantages of lipase-catalyzed transesterification
advantages : no soap formation; low energy consumption; high product purity
disadvantages : slow rate of reaction; expensive catalyst; loss of effectiveness over time
hydration of ethene
(exothermic addition reaction)
ethene + steam → ethanol
H₃PO₄/300°C/60-70atm
what is the conversion rate of hydration of ethene ?
5% each time ethene is passed over the catalyst
95% by repeating the process
enzyme-catalyzed fermentation of ethanol
starch + amylase → maltose
maltose + maltase → glucose
glucose + zymase → ethanol
(C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂)
why is enzyme-catalyzed fermentation of ethanol only successful up to 15% ethanol ?
↑[C₂H₅OH] poisons the yeast which carries zymase that catalyzes C₆H₁₂O₆ → C₂H₅OH
theoretical yield
assuming 100% conversion of reactants → products according to stoichiometry
actual yield
real conversion of reactants → products according to experimental data
what causes actual yield to be lesser than theoretical yield ?
reaction stops at equilibrium instead of completion
slow rate of reaction (time runs out)
loss of reactants/products during transfers
percentage yield
[(actual yield) ÷ (theoretical yield)] × 100
overall percentage yield (A → B & B → C)
(Yield₁ × Yield₂) × 100
