Flashcards

nitroalkanes

arwk CHEMISTRY sat English 33 cards

Cards in this deck (33)

1NITROALKANESH replaced BY NO2
2anniline
3Primary amines (1)in primary amines only one hydrogen atom in ammonia is replaced by one alkyl or aryl group
4secondary aminein secondary amines two hydrogens of ammonia are replaced
5tertiary aminesin tertiary amines all 3 hydrogens of ammonia are replaced
6simple amine(C2H5)2 NH
7mixed amine
8strucure of amine- is trivalent and carries an unshared pair of electrons
-sp3 hybridised and the geometry
of amines is pyramidal.
-.---Each of the three sp3 hybridised orbitals of nitrogen overlap with orbitals of hydrogen or carbon depending upon the composition of the amines.
9bond angle amine----The fourth orbital of nitrogen in all amines contains an unshared pair of electrons.
-----Due to the presence of unshared pair of electrons, the angle C–N–E, (where E is C or H) is less than 109.5°.
---- for instance, it is 108 in case of trimethylamine amine
10NOMENCLETURE -1
11NOMENCLETURE -2
12LOWER AMINES AREcolourless and have fishy odour
13primary amines having 3 or more carbon atoms are in which stateliquid
14some physical properties+ primary ,sec,tert amines form hydrogen bonds with water
+ solubility is directly prop to molecular mass
+aryl amine ----> toxic in nature
+ exposure to air the amines become coloured
++ pri, sec amines have more h bonding than tert due to intermolecular association with h bonds
++boiling point pri > sec > tert
++ polarity alcohols >> amine>> alkanes
15BASICITY OF AMINES1.According to Lewis theory, the species which donates a lone pair of electrons is called a base.
2.) The nitrogen atom in ammonia carries a lone pair of electron, which can be donated for the formation of a co-ordinate bond.
3.) Thus amines are basic in nature and are Lewis bases.
4.) An amine also acts as Bronsted Lowry base as it accepts a proton from acid.
16BASICITY OF AMINES 2
17AMINES TURN red litmus -BLUEEEEEEEE AND SO THEY ARE BASES
18Ammonium salts on treatment with a base
19Ammonium salts on treatment with a base 2
20amines are weak base thanalkali NaOH or KOH.
21ALSO BASICITY CAN BE EXPLAINED BY
22Comparison of basicity of aliphatic amines and ammoniaAliphatic AMINEs are stronger bases than ammonia. Due to electron releasing inductive effect (+1 effect) of the alkyl groups in aliphatic amines, the electron density on the nitrogen atom increases and the lone pair of electron becomes readily available for protonation.
23Compare the basicity of Primary, secondary and tertiary aminesbasic nature of aliphatic amines should increase with the increase in number of alkyl groups,
3° arnines > 2° amines > 1° amines > ammonia.
24Comparison of basicity of aromatic amines and ammonia--Aromatic amines are weaker bases than ammonia
- electron withdrawing nature of the aryl group.
25Compare the basicity of Primary, secondary and tertiary amines in aquesous phase+ solvation of ammonium +water should be considered
+ size of ion increases , solvation decreases , stability decreases
+sec and tert amine -----> steric hindrance------> bulky r grp
+ so the H2O molecule cannot approac to it so the basic strength decreases
+ pri > sec > tert
26general order of basicitysec > pi > tert
due to
1 inductive effect
2 solvation effect
3 steric hindrance
27stability of aniline and anilinium ion.Anilinium ion can have only two resonating structures.
where as anniline has many resonating structures so anniline is more stable
28basicity of aniline and anilinium ion.----aniline has very little tendency to combine with a proton to form anilinium ion and therefore, aniline is less basic.
----In case of substituted aniline, electron releasing groups like OCH3, —CH3, —NH2 increase the basic strength whereas electron withdrawing groups like —NO2, —C6H5, —SO3, —COOH, —CN, —x decrease it.
29aromatic amines and ammonia basearomatic amines are weaker base than ammonia
30alkylationThe process of introducing an alkyl group in amines is called alkylation of amines.
31methylation of amines ?The reaction in which a hydrogen atom attached to the nitrogen atom in amines is replaced by methyl group is called methylation of amines
32Hoffmann’s carbylamine reactiona. Aliphatic or aromatic amines on heating with chloroform and alcoholic potassium hydroxide form isocyanides or carbylamines having foul smell.
b. Secondary and tertiary amines do not show this reaction. This reaction is known as carbylamine reaction.
33Hoffmann elimination:Quaternary ammonium hydroxides on strong heating undergo 13 — elimination to give alkenes, the reaction is called Hoffmann elimination.