Names And Conditions Of Mechanisms, And Key Definitions Flashcards
What is the name, reagent and conditions for the mechanism from Haloalkane to Alcohol?
Nucleophilic Substitution
Reagent: NaOH
Conditions: Aqueous, heat under reflux
What is the name, reagent and conditions for the mechanism going from Haloalkane to Amine?
Nucleophilic Substitution
Reagent: Excess NH3
Conditions: Ethanol, heat and pressure
What is the name, reagent and conditions for the mechanism going from Haloalkane to Nitrile
Nucleophilic Substitution
Reagent: KCN
Conditions: Water and ethanol
What is the name of the process, reagent and conditions to go from Nitrile to Amine?
Reduction
Reagent: H2 (in the equation; 2H2)
Condition: Nickel (Ni) catalyst
What is the name, catalyst and conditions for the mechanism going from Alcohol to Alkene?
Elimination/Dehydration
Catalyst: Hot concentrated H2SO4
Conditions: Hot
What is the name, reagent and conditions for the mechanism going from Alkene to Alcohol?
Direct Hydration
Reagent: H3PO4
Conditions: Steam
What is the name, reagent and conditions for the mechanism going from Haloalkane to Alkene?
Elimination
Reagent: KOH/NaOH (acts as base, not nucleophile)
Conditions: Ethanol, Reflux
What is the name, reagent and conditions for the mechanism going from Alkene to Haloalkane?
Electrophilic Addition
Reagent: HBr, HCl, Br2, Cl2
Conditions: No conditions required
What is the name and reagent for the mechanism going from Alkene to Alkyl Hydrogen Sulfate?
Electrophilic Addition
Reagent: H2SO4
What is the name of the process of going from Alkyl Hydrogen Sulfate to an Alcohol, and what is the reagent?
Hydrolysis
Reagent: H2O
What is the name, reagent and conditions for the process of going from Alkane to Haloalkane? And what are the names of the steps?
Free Radical Substitution Reagent: Either Br2 or Cl2 Condition: U.V light Steps: Initiation Propagation (two equations) Termination
Define a Nucleophile
An electron pair donor
Define an Electrophile
An electron pair acceptor (AKA a reactive intermediate
Define a Base
A proton acceptor
Define an Acid
A proton donor
What is meant by “More Stable Carbocation”?
The major product has the more stable carbocation. It’s a positive carbon with more carbons around it. E.g a 1° carbocation is less stable than a 2° one.
This is due to the positive inductive effect.
Define the Positive Inductive Effect
The ability to release electron density through a covalent bond
What is the name, reagent and conditions for the mechanism for the Nitration of Benzene (Forms Nitrobenzene)? How is the electrophile/reactive intermediate formed?
How is the Catalyst Re-Formed?
Electrophilic Substitution
Reagent/Conditions: Conc HNO3 and Conc H2SO4 Catalyst
H2SO4 + HNO3 —> HSO4- + H2O + NO2+
HSO4- + H+ —> H2SO4
What is the name, reagent and conditions for the mechanism going from Benzene to Phenylethanone (Friedel-Crafts Acylation)
What is the equation for the formation of the electrophile/reactive intermediate
How is the catalyst Re-Formed?
Electrophilic Substitution
Conditions/Reagents: An acyl chloride e.g RCOCl and an AlCl3 catalyst
RCOCl + AlCl3 —> RCO+ + AlCl4-
(RCO+ = Electrophile)
AlCl4- + H+ —> AlCl3 + HCl
What occurs when forming an Amine from a Haloalkane, if the Haloalkane is also in Excess as well as the NH3?
Further Substitution
Product reacts with Haloalkane to form a 2° anime, and that product reacts to form 3° amine and then that product reacts to form a Quaternary (4°) Ammonium Salt (used in hair conditioner)
What are the Cons to forming an Amine from a Haloalkane for either nucleophilic substitution with excess NH3 (Route 1), or nucleophilic substitution with KCN to form Nitrile, and then reduction with 2H2 and Ni catalyst (Route 2)?
Route 1: Risks Further Substitution
Route 2: KCN is Toxic and also it requires two steps instead of one
What is the name of the process, reagent and conditions for turning the Nitro group (NO2) on Nitrobenzene to an Amine group (NH2)? Give a general equation for the transformation of the alkyl group.
Reduction Reagent: HCl Condition: Tin (Sn) Catalyst NO2 + 6[H] ---> NH2 + 2H2O (NO2 and NH2 are attached to benzene)
What is the risk of reacting HCl with Nitrobenzene to change group to an amine group? And how is this solved?
Risk of product reacting with HCl to form Phenylammonium Chloride
(NH2 group becomes NH3+ with Cl- nearby like when amino acids are in acidic conditions)
Solution:
Add stronger base (NaOH)
NH3+ + Cl- + NaOH —> NH2 + NaCl + H2O
(NH2 and NH3+ are attached to benzene)
What is the name, reagent and conditions for the mechanism going from a Ketone to a 2° Alcohol or an Aldehyde to a 1° Alcohol?
(Reduction)
Nucleophilic Addition
Reagent: NaBH4
(For hydride ion nucleophile :H- )
Condition: Acidic Solvent Needed (For H+ in mechanism)
What is the name, reagent and conditions for the mechanism going from either a Ketone or Aldehyde to a 2° or 1° Hydroxy Nitrile group
(Reduction)
Nucleophilic Addition
Reagent: Potassium Cyanide, KCN, Aqueous and Ethanolic
(Nucleophile: -CN)
Conditions: Acidic Solvent Needed (For H+ in mechanism)
Give the name, conditions and reagent for the 1st method of making esters that you learnt.
Esterification (Reversible via hydrolysis)
Reagent: Carboxylic Acid + Alcohol
Conditions: Concentrated H2SO4 (H+) catalyst and Gentle Heat
(H2O is a side product)
What is Hydrolysis?
The breaking of covalent bonds using water
What are the two methods of Hydrolysis for splitting Esters? And what do both methods form?
Acid-Catalysed Hydrolysis
Reagent: Water
Conditions: Room Temp and Strong Acid Catalyst
Forms: Carboxylic acid and Alcohol
Base-Catalysed Hydrolysis
Reagent: Warm AQUEOUS NaOH
Forms: Salt of the acid (e.g Sodium Propanoate if using ‘something’ Propanoate) and Alcohol
(Once carboxylic acid forms, it reacts with NaOH in an acid base reaction)
What is meant by the term Unsaturated when applied to an Alkene?
Contains a C=C bond
Give the name, reagent and conditions for the mechanism used in the 2nd way if forming Esters you learnt
Addition-Elimination
Reagent: An Alcohol and an Acyl Chloride (RCOCl, all have names ending with ‘Oyl Chloride’)
No specified conditions
Give the name of the reagents for the 3rd way of forming an ester, more specifically, aspirin.
Salicylic Acid and Ethanoic Anhydride (Practical 10 on paper 2)
For Industrial Use of Acylation Reactions, why is it more beneficial to use Acid Anhydrides (RCOOCOR’) over Acyl Chlorides (RCOCl)? 4 reasons
- Cheaper
- Less Corrosive
- Doesn’t react with water to form a carboxylic acid
- Safer as side product is Carboxylic acid and not HCl vapours
Give the name and products for the mechanism when H2O is added to an Acyl Chloride (RCOCl)
Addition-Elimination
Products: Carboxylic acid and HCl vapours
Give the name and products for the mechanism when ammonia (NH3) is added to an Acyl Chloride (RCOCl)
Addition-Elimination
Products: Amide (RCONH2) and NH4Cl
(Ammonium chloride salt)
Give the name and products for the mechanism when an Amine is added to an Acyl Chloride (RCOCl)
Addition-Elimination
Products: N-Substituted Amide (RCONHR’) and an Ammonium Chloride Salt (RN(+)H3Cl)
Why are Addition Polymers non-biodegradable? And how are they disposed instead?
C-C bonds in carbon chain are Non-Polar so cannot be attacked by nucleophiles therefore can’t be hydrolysed by H2O
They are incinerated or buried
Why are Condensation Polymers biodegradable?
‘C’ in polar C-O can be attacked by nucleophiles so can be hydrolysed under acidic or basic conditions
How is the condensation polymer ‘Polyester’ formed?
From a Dicarboxylic acid and Alcohol (Diol)
How is the condensation polymer ‘Polyamide’ formed?
From a Dicarboxylic acid and Diamine
What are the uses of Polyesters?
Terylene
Carpets, clothing, heat treated polyesters used in drink bottles
What are the uses of Polyamides
Nylon 6,6: Fibres in clothing as it is elastic and has strong abrasion resistance
Kevlar: Body Amour and Crash Helmets as it is strong, light and heat resistant
What are the reagent, condition and products for the Base Hydrolysis of Polyesters?
Reagent: H2O
Condition: NaOH
Products: Salt of Dicarboxylic acid, and Alcohol (Diol)
What are the reagent, condition and products for the Acid Hydrolysis of Polyesters?
Reagent: H2O
Condition: H+
Products: Dicarboxylic Acid and Alcohol (Diol)
What are the reagent, condition and products for Base Hydrolysis of Polyamides?
Reagent: H2O
Condition: NaOH
Products: Salt of Dicarboxylic Acid and Diamine
What are the reagent, condition and products for Acid Hydrolysis of Polyamides?
Reagent: H2O
Condition: H+
Products: Diammonium Salt (NH3+) and Dicarboxylic Acid
What is an amino acid? And subsequently what is an alpha amino acid
Made from a carboxylic acid and an amine, and and alpha amino acid has 1 carbon between them with an R group attached to it
What happens to an amino acid at neutral pH?
Zwitterions form
+NH3 and COO-
Key Facts About Zwitterions (3)
Form a solid lattice of Zwitterions
(Strong Electrostatic Forces Of Attraction Between COO- and +NH3)
Soluble as H2O can bond with COO- and +NH3
Mostly found as Solid or (aq)
What happens to an Amino Acid in Acidic Conditions? (HCl)
Amino acid gets protonated:
NH2 group becomes Cl- +NH3
And also R group gets protonated if it also contains an amine group
What happens to an Amino Acid in Alkaline conditions? (NaOH)
Amino acid gets Deprotonated:
COOH becomes COO- Na+ H2O
R group also gets Deprotonated if it contains a COOH group
What is a peptide?
When amino acids join to form a chain (connected by a peptide bond/amide link) (O=C-N-H)
If two amino acids are in a chain it is a…
Dipeptide
If three amino acids are in a chain it is a…
Tripeptide
What are the conditions for the hydrolysis (splitting) of peptides?
Boil (24 hrs)
6moldm-3 HCl catalyst
What is the primary (1°) structure of a protein?
A sequence of amino acids (with the order and structure of these acids being crucial to the structure and function of the protein)
E.g. Glycine-Alanine-Valine-Leucine
What is the secondary (2°) structure of a protein? And how is it held together?
Alpha-Helix or Beta-Pleated Sheet
Delta +ve hydrogen on N-H in amide link on one peptide chain forms a hydrogen bond with lone e- pair on C=O on amide link on another peptide chain
(R group may also form hydrogen bonds)
What is the tertiary (3°) structure of a protein?
Alpha-Helix/ Beta-Pleated Sheet folds into a 3D shape
How is the Tertiary (3°) structure of a protein held in place?
-Hydrogen bonding
-Some Ionic interactions
-Disulfite bonds (S-S) if two cysteine amino acids
(Covalent bond so stronger than H- Bond and has greater affect on structure)
Key Enzyme Facts (3)
- Catalyse just one type of reaction
- Active Site is where the reaction takes place
- It is “Stereospecific” and fits only one type of optical isomer
What is the name of the reaction for producing Ethanol from Glucose? And what is the equation for it?
Fermentation/Anaerobic Respiration
C6H12O6(aq) —> 2CH3CH2OH(aq) + 2CO2(g)
What are the conditions for fermentation?
Yeast, 35°C and NO oxygen
Advantages of the Hydration of Ethene to form Ethanol?
- Large scale production method
- High purity product made
- Readily available raw material
- High reaction rate
- Continuous Production Method
Disadvantages of the Hydration of Ethene to form Ethanol
- High temperature and pressure required so higher cost
- Expensive/High cost equipment required
- Crude oil is non renewable
Advantages of Fermentation to form Ethanol
- Uses renewable resources
- Low tech method, so suitable for developing countries
- Readily available and renewable materials
- Low cost
Disadvantages of Fermentation to form Ethanol
- Slow rate of reaction
- Impure Ethanol made needs distilling
- Causes food prices to rise if crops are used to make ethanol instead of food
- Batch production method is less effective
Name N-Substituted Amide CH3CONHCH3
N-methylethanamide
What is used as a reference standard in CNMR and HNMR spectroscopy? And what does it do?
TMS, aka tetra methyl saline.
Creates sharp peak at 0ppm.
Why do we use TMS apart from due to its sharp peak?
It is unreactive
It is highly volatile (can be removed by evaporation easily)
Peak is always to right of spectrum
Recrystallization steps for formation of Aspirin from Salicylic acid and Ethanoic anhydride (6 marks)
-Weigh mass of aspirin produced and add a minimum amount of hot solvent to form a highly concentrated saturated solution.
(Minimum amount maximises the yield of crystals at the end)
- Filter it Hot to remove insoluble impurities
-Cool it back down to get insoluble crystals to form
- Filter under reduced pressure and wash with cold solvent to remove soluble impurities
-Dry the sample
Hydrogen based fuels create pollutants when combusted such as S(s) and N2(g). How do these react with oxygen at high temp? (2 equations as there is a further reaction for N2)
S(s) + O2(g) –> SO2(g)
N2 (g) + O2 (g) —> 2NO(g)
2NO(g) + O2 –> 2NO2 (g)
How do both SO2 and NO2 dissolve in water to form acid rain?
SO2(g) + 0.5O2(g) + H2O(l) —> H2SO4(l)
4NO2(g) + O2(g) + 2H2O(l) —->
4HNO3 (l)
What metal used as a catalyst makes up the structure of a catalytic converter?
And why does it have a honeycomb structure?
Platinum/Rhodium/Palladium
Increases surface area and thus reaction rate
Equation for a catalytic converter removing Nitrogen monoxide and Carbon monoxide
2NO(g) + 2CO(g) —> N2(g) + 2CO2(g)
How does a catalytic converter remove nitrogen monoxide and unburnt hydrocarbons? (Just name products)
N2, CO2 and H2O
Two methods of flue gas desulfurization
Both make CaSO4
CaO(s) + 2H2O(l) + SO2(g) + 0.5O2(g) –>
CaSO4.2H2O(s)
CaCO3(s) + SO2(g) + 0.5O2(g) –> CaSO4 + CO2
What does catalytic cracking make and what are the conditions and catalyst required?
Makes branched alkanes and cycloalkanes
Requires high temp (700K) and moderate pressure
Requires Zeolite Catalyst
What does thermal cracking make and what does it require?
2 alkenes and 1 alkane (high demand)
Requires high temp and high pressure
