(yellow) organic analysis and synthesis Flashcards
(yellow) organic analysis and synthesis
what are some compounds that absorb water . therefore can be used to measure water absorbtion
anhydrdrous calcium chloride or anhydrdrous copper sulphate (II)
if a organic compound is burnt under a flame and produces a clean blue flame what is it
alcohol
if a organic compound is burnt under a flame and produces a yellow flame what is it
alkane
if a organic compound is burnt under a flame and produces a smoky yellow flame what is it
unstaurated / aromatic
*(may need to edit later)
carbon composition is greater in unsaturated compounds therefore this leads to more oxygen being used, which causes less oxygen in the surrounding enviroment leading to incomplete combusiton
comment on the solubility of hydrocarbens
no soluable immiscuble forming two layers
comment on the solubility of alcohols
dipole , forms hydrogen bonds
comment on the solubility of carboxilic acids and amine
very soluable , H0bonding
what are the observations when you put an alkene with bromine water
goes from brown to colourless and produces a H and Br neighbours on the double bond carbon
what are the observations when you put an alkene with KMnO4 / H2SO4
purple to colourless
also produces two dioles (oh x 2)
how do you go from a nitrile R-CN to a R-CH2-NH2
LiAlH4 in dry ether
how do you go from a nitrile R-CN to a carboxilic group
dil HCl which causes hydrolisation
how do you go from a halogeno alkane to a nitrile
KCN in ethanol which acts as a solvent has to be in alkali conditions
what would happen if you added KCN or HCN to a ketone
you would produce a hydroxy nitrile
how would you go from a hydroxy nitrile R-C(OHCN) - R to a carboxilic group and alcohol group R-C(OHCOOH) - R
dil HCl
how would you go from a hydroxy nitrile R-C(OHCN) - R to a reduced CH2-NH2 group instead of the CN gorup
LiALH4 in dry ether
Alkene to Halogenoalkane
type of reaction , reagent and conditions
Halogen or Hydrogen Halid
addition
type of reaction , reagent and conditions
alkene to alkane
Hydrogen and Pt/Pd catalyst
addition
reduction
type of reaction , reagent and conditions
alkene to alcohol
Steam and acid catalyst (phosphoric acid)
addition
type of reaction , reagent and conditions
alkene to diol
KMnO4/dil NaOH, cold KMnO4/dil H2SO4, warm
addition
type of reaction , reagent and conditions
carbonyl to hydroxynitrile
HCN and KCN
addition
type of reaction , reagent and conditions
alkane to Halogenoalkane
Halogen and UV light
substitution
type of reaction , reagent and conditions
Halogenoalkane to alcohol
NaOH(aq)
sub
type of reaction , reagent and conditions
Halogenoalkane to nitrile
KCN (ethanol)
sub
type of reaction , reagent and conditions
Halogenoalkane to amine
NH3 (ethanol)
sub
type of reaction , reagent and conditions
Alcohol to Halogenoalkane
PCl5 / PBr3 /PI3 or HCl / HBr (made in situ)
sub
type of reaction , reagent and conditions
Acyl chloride to Carboxylic acid
H2O
SUB
type of reaction , reagent and conditions
Acyl chloride to ester
alcohol
SUB
type of reaction , reagent and conditions
Acyl chloride to Amide
Ammonia
SUB
type of reaction , reagent and conditions
Acyl chloride to N sub amide
amine
type of reaction , reagent and conditions
1.Alkene to diol
KMnO4 + acid
oxidation
type of reaction , reagent and conditions
Aldehyde to carboxilic acids
K2Cr2O7 + Sulfuric acid or Tollens or Fehling
oxidation
type of reaction , reagent and conditions
nitrile to amine
LiAlH4 (dry ether) or H2 & Catalyst
reduction
type of reaction , reagent and conditions
. Carboxylic acid + alcohol to ester
Acid catalyst
condensation
type of reaction , reagent and conditions
3.Acid chlorides + H2O, ROH, NH3, RNH2 to Carboxylic acid, ester, (N-subs)amide
Dry
oxidation
type of reaction , reagent and conditions
Halogenoalkane to alkene
Con KOH (ethanol) heat under reflux
elimination
type of reaction , reagent and conditions
alocohols to alkene
Con Sulphuric acid and high temp
eliminaiton
type of reaction , reagent and conditions
Carboxylic acid + alkali to salt + water
Room temp
acid / base
type of reaction , reagent and conditions
Amine + HCl to alkyl ammonium salt
Room temp
acid / base
type of reaction , reagent and conditions
Benzene to Bromobenzene
FeBr3 and Br2
SUB
type of reaction , reagent and conditions
Benzene to Nitrobenzene
Con H2SO4 and Con HNO3 Heat under reflux
SUB
type of reaction , reagent and conditions
Benzene to Alkylbenzene
Halogenoalkane & AlCl3 Heat under reflux
SUB
type of reaction , reagent and conditions
Benzene to Alkylbenzene
Acyl Chloride & AlCl3 Heat under reflux
SUB
type of reaction , reagent and conditions
Phenol to 2 4 6 tribromophenol
Bromine water
read
Other points to consider when choosing a route
Yields
The fewer steps the better – why?
· Organic reactions seldom produce a yield of >50%.
· The products requires often have to be separated before the next stage.
How easy will it be to separate the product
· It is usually easier to separate and purify solid products.
· Recrystallisation of solids or fractional distillation of liquids
Isomerism Will isomers be formed? Which types of reactions result in isomer formation?
· Addition reactions when Nucleophilic Addition. Racemic mixtures due to addition to a planar starting material
· Substitution reactions e.g. SN1 Racemic mix due to planar intermediate carbocation SN2 optical product only one direction to attach C delta +ve
· Elimination reactions e.g.to form cis or trans products
Why is the formation of isomers a problem in synthesis?
· May result in different products in subsequent reactions
· Biological systems require stereo-specific molecules
how does mass spec work and what are its key principals
how it works
High energy electrons bombard sample knocking off an electron. Also possible fragmentation
Key information gained
Molecular weight value from m/z Formula from High resolution Mass spec with M/z values to 4 dp Stable fragments have high percentage abundance
how does IR work and what are its key principals
how it works
IR radiation absorbed by sample causes bonds to vibrate etc. Must be polar bonds.
key information :
Below 1500 wavenumbers fingerprint region can be used to identify compound. Above 1500 can be used with data book to give information about the bonds which are present
how does C NMR work and what are its key principals
how it works :
Radio waves absorbed by sample
key info :
No of C in different environments – no of peaks Chemical shift – the nature of the C environmen
how does H NMR work and what are its key principals
how it works
Radio waves cause H nuclei to flip to a high energy state
key info :
No of H in different envionments by o of peaks Area under curve – No of H in each environment Chemical shift – the nature of the H environment High resolution Splitting pattern - The number in adjacent inequivalent H’s ie the n+1 rule
what is the basic function of recystalisation and also what is its steps
basic function : product is soluable in hot solvent but not in cold solvent
1 . min qualintaty of solvent added to impure substance
- warmed to dissolve substance , insoluable impuritys left
- Hot filtration removes insoluable inpuritys
- allow to cool and substance crystallises out leaving soluable impuritys in
- filter off crystalls rinse and dry
rinse : rinses out in cold solvent so impuritys dissolve
dry : oven or between two filter papers
