AMINES Flashcards
WHAT ARE ALIPHATIC AMINES?
THESE ARE PRIMARY, SECONDARY OR TERTIARY AMINES WHERE THE R GROUP ATTACHED TO THE CARBON IS AN ALKYL GROUP. (METHYL, ETHYL, ETC)
WHAT ARE ACROMATIC AMINES?
WHERE THE R GROUP IS A ARYL GROUP (BENZENE RING OR PHENYL GROUP)
HOW CAN AMINES BE PREPARED (MADE), AND GIVE THE CONDITIONS NEEDED FOR EACH METHOD OF PREPARATION, AS WELL AS THE TYPE OF MECHANISM REACTION?
1) REACTIONS OF HALOGENOALKANES WITH NH3 (AMMONIA). CONDITIONS: HOT, EXCESS, ALCOHOLIC AMMONIA UNDER PRESSURE, PRODUCING A PRIMARY AMINE IN A NUCLEOPHILIC SUBSTITUTIONR REACTION.
2) REDUCTION OF NITRILES. CONDITIONS: NITRILE VAPOUR AND H2 GAS (HYDROGEN) ARE PASSED OVER NICKEL CATALYST OR LIALH4 IS USED IN DRY ETHER TO FORM A PRIMARY AMINE. HENCE NITRILES CAN BE REDUCED USING LIALH4 OR H2 GAS AND NICKEL CATALST. (MAIN CONDITIONS ARE EITHER REACT NITRILE WITH LIALH4 TO REDUCE IT (H+ REAGENT), OR REDUCE IT USING H2 GAS AND NICKEL CATALYST.
GIVE THE STEPS TO PRODUCE THE ACROMATIC AMINE (BENZENE RING/PHENYL GROUP CONTAINING), PHENYL AMINE?
S1: BENZENE IS UNDERGOES NITRATION WITH CONC. H2S04 AND CONC. HNO3 IN (25-60 DEGREES) TO FORM NITRO BENZENE.
S2: NITROBENZENE IS THEN REDUCED WITH HOT TIN (Sn), OR/AND CONC. HCL UNDER REFLUX TO FORM AN ACIDIC MIXTURE THAT CONTAINS THE ORGANIC PRODUCT, C6H5n+H3).
S3: ADD NAOH TO THIS ACIDIC MIXTURE TO FORM PHENYLAMINE.
(FOR PURIFICATION) S4: PHENYL AMINE UNDERGOES STEAM DISTILLATION TO BE SEPARATED FROM THE REACTION MIXTURE. IN THE EQUATION 2H20 is by product.
HOW AND WHY CAN NITROGEN IN AMMONIA ACT AS A BASE?
THE NITROGEN IN AMMONIA CAN ACCEPT A PROTON AND THEREFORE ACT AS A BASE IN AQUEOUS SOLUTIONS BY DONATING ITS LONE PAIRS OF ELECTRONS TO A PROTON (h+), and hence forming a dative covalent bond.
LIKE AMMONIA, AMINES CAN REACT WITH HCL TO FORM WHAT?
AMMONIUM SALTS.
AMMONIUM AND AMINE SALTS ARE SOLUBLE IONIC COMPOUNDS AND HENCE WATER SOLUBLE WHEN THE ALKYL GROUP IS SMALL. BUT THEY BECOME LESS _______, AS ______ INCREASES?
THEY BECOME LESS SOLUBLE AS THE CARBON CHAIN INCREASES.
THE STRENGTH OF AMMONIA AND AMINES AS BASES IS DETERMINED BY WHAT?
THEIR ABILITY OF THE LONE PAIR ON THE N ATOM TO BE DONATED TO h+ (proton), and form a dative covalent bond.
GIVE AND EXPLAIN THE FACTORS THAT AFFECT BASICITY OF AMINES?
POSITIVE INDUCTIVE EFFECT: GROUPS LIKE ALKYL GROUPS DONATE ELECTRON DENSITY TO THE N ATOMS, SO THE LP ON THE N ATOM BECOMES MORE AVAILABLE, HENCE A DATIVE COVALENT BOND CAN FORM, INCREASING THE BASICITY OF THE AMINES.
DELOCALISTION: ACROMATIC (BENZENE) RINGS PRESENCE, MEANS THAT THE LONE PAIR OF ELECTRONS ON THE N ATOMS ARE DELOCALISED INTO THE RING, MAKING THEM LESS AVAILABLE TO FORM A DATIVE COVALENT BOND. DECREASING THE BASICITY OF AMINES.
EG QUESTION, FROM STRONGEST TO WEAKEST BASE WHICH ONE OF THESE COMPOUNDS ARE THE STRONGEST, AND WHICH IS IN THE MIDDLE, AND WHICH IS THE WEAKEST. AMMONIA, PHENYL AMINE, ETHYL AMINE.
STRONGEST BASE - ETHYL AMINE: THE POSTIVE INDUCTIVE EFFECT OF THE ALKYL GROUPS INCREASES THE ELECTRON DENSITY OF N ATOM, HENCE THE LONE PAIRS ON N BECOME MORE AVAILABLE, MAKING THEM MORE ATTRACTIVE TO PROTONS, HENCE FORMING A DATIVE COVALENT BOND.
MIDDLE BASE - AMMONIA: NO ALKYL GROUPS ARE PRESENT TO DONATE ELECTRON DENSITY AND CAUSE POSITIVE INDUCTIVE EFFECT, AND NO ACROMATIC (BENZENE) RINGS ARE PRESENT TO CAUSE THE LONE PAIRS ON N TO BE DELOCALISED INTO THE RING.
WEAKEST BASE - PHENYL AMINE: ACROMATIC (BENZENE) RING PRESENT MEANS THAT THE LONE PAIRS OF ELECTRONS ON N ATOM BECOME DELOCALISED INTO THE RING, CAUSING THEM TO BE LESS AVAILABLE TO FORM A DATIVE COVALENT BOND WITH h+ (proton).
WHATS THE NAME OF THE REACTION MECHANISM TYPE THAT INVOLVES THE FORMATION OF AMIDES FROM REACTION AMINES/AMMONIA WITH ACYL CHLORIDE.
NUCLEOPHILIC ADDITION ELIMINATION.
GIVES THE DIFFERENCES IN THE PRODUCT FORMED IN THE NUCLEOPHILIC ADDITION ELIMINATION REACTION BETWEEN AMMONIA AND ACYL CHLORIDE, AND AMINE AND ACYL CHLORIDE.
WITH AMMONIA - THE PRODUCT IS A NON - SUBSTITUTED AMIDE ( non-substitued meaning The nitrogen has two hydrogens attached → no alkyl groups
So it’s called a non-substituted (or primary) amide)
AND WHITE FUMES OF NH4CL ARE FORMED (as a result of CL reacting with excess/remaining nh3 in HCl + NH₃ → NH₄Cl)
WITH AMINES - THE PRODUCT IS A SUBSTITUTED AMIDE (the N has alkyl groups) AND THE HCL FORMED REACTS WITH THE UNREACTED AMINE TO FORM A WHITE ORGANIC AMMONIUM SALT.
IN THE REACTION OF PROPANOYL CHLORIDE WITH A PRIMARY AMINE, METHYL PROPANAMIDE IS PRODUCED ALONGISDE THE BY PRODUCT HCL. HCL IS THEN INVOLVED IN AN ACID - BASE REACTION, AS THE FINAL STEP. WHAT DOES IT REACT WITH AND WHAT DOES IT FORM.
HCL REACTS WITH THE SAME ORIGINAL PRIMARY AMINE NUCLEOPHILE, TO FORM AMMONIUM SALT CH3Nh3+CL-. hcl acts as the acid and the primary amine (nh2ch3) acts as the base)
QUATERNARY AMMONIUM SALTS ARE VERY USEFUL IN MANUFACTURE OF CLEANING PRODUCTS LIKE WHAT?
CONDITIONERS FOR WASHING HAIR, AND IN FABRIC SOFTENERS
AMMONIUM SALTS ACT AS CATIONIC SURFACTANTS. WHAT ARE SURFACTANTS.
SURFACTANTS ARE CHEMICALS THAT LOWER THE SURFACE TENSION BETWEEN IMMISCIBLE LIQUIDS AND ALLOW WETTING TO TAKE PLACE.
AMMONIUM SALTS ARE CATIONIC BECUASE _____?
THE + CHARGE ON N
THE HYDROCARBON BEING HYDROPHOBIC AND THE AMINE GROUPS BEING HYDROPHILIC ALLOWS THE MOLECULES TO DO WHAT?
CLUSTER ON THE SURFACE OF H20 WITH THEIR HYDROPHILIC CHARGED ENDS IN THE WATER AND THEIR HYDROPHOBIC TAILS ON THE OUTER SURFACE. HENCE THE TERM SURFACTANT.
