Borazone OR Borazone

ppt for college seminar

1. Borazine
THE INORGANIC BENZENE
B
3N
3H
6

2. Definationof Borazine
Borazeneisa colorless volatile liquid compound B
3N
3H
6
that is formed by heating diborane and ammonia and has a structure like that of benzene with
alternating boron and nitrogen atoms in a ring
—called alsotriborinetriamine
ANOTHER DEFINATION :
Borazineis aninorganic compoundwith thechemical formula(BH)
3(NH)
3. In thiscyclic compound,
the three BH units and three NH units alternate. The compound
isisoelectronicandisostructuralwithbenzene. Like benzene, borazine is a colourlessliquid.

3. Structure of Borazine

4. BORAZINE IS ISOELECTRONIC WITH BENZENE AND HAS
SIMILAR CONNECTIVITY, SOIT IS SOMETIMES REFERRED TO
AS "INORGANIC BENZENE".
THIS COMPARISON ISNOT RIGOROUSLY VALID DUE TO
THEELECTRO-NEGATIVITY DIFFERENCEBETWEENBORON
AND NITROGEN.
X-RAY CRYSTALLOGRAPHIC STRUCTURAL
DETERMINATIONSSHOW THAT THE BOND LENGTHS WITHIN
THE BORAZINE RING ARE ALL EQUIVALENTAT 1.429 Å, A
PROPERTY SHARED BY BENZENE.

5. oTHEELECTRONEGATIVITYOF BORON (2.04 ON THEPAULING SCALE)
COMPAREDTOTHAT OF NITROGEN (3.04) AND ALSO THE ELECTRON
DEFICIENCY ONTHEBORONATOM AND THE LONE PAIR ON
NITROGENFAVORALTERNATIVEMESOMERSTRUCTURES FOR
BORAZINE.
oBORON BEHAVES AS ALEWIS ACIDAND NITROGEN BEHAVES AS
ALEWIS BASE.

6. Synthesis of Borazine
Borazine is synthesized fromdiboraneandammoniain a 1:2 ratio at
250–300°C with aconversionof 50%.
3 B
2H
6+ 6 NH
3→ 2 B
3H
6N
3+ 12 H
2
An alternative more efficient route begins withlithium
borohydrideandammonium chloride:
3 LiBH
4+ 3 NH
4Cl → B
3H
6N
3+ 3 LiCl + 9 H
2
In a two-step process to borazine,boron trichlorideis first converted
to trichloroborazine:
3 BCl
3+ 3 NH
4Cl → Cl
3B
3H
3N
3+ 9 HCl
The B-Cl bonds are subsequently converted to B-H
bonds: 2 Cl
3B
3H
3N
3+ 6 NaBH
4→ 2 B
3H
6N
3+ 3
B
2H
6+ 6 NaCl

7. Reactivity :
Although often compared with benzene, borazine is far more
reactive. Withhydrogen chlorideit forms anadduct, whereas
benzene is unreactive toward HCl.
B
3N
3H
6+ 3 HCl → B
3N
3H
9Cl
3
Addition reaction of borazine with hydrogen chloride
B
3N
3H
9Cl
3+ NaBH
4→ (BH
4N)
3
Reduction withsodium borohydride

8. The addition reaction withbrominedoes not
require acatalyst.
Borazines undergonucleophilicattack at
boron andelectrophilicattack at nitrogen.
Heating borazine at 70°C expels hydrogen
with
formationofa borazinylpolymer or polybora
zylene, in which the monomer units are
coupled in apara fashionby new boron-
nitrogen bonds.
Boron nitridecan be prepared by heating
polyborazyleneto 1000°C.
Borazines are also starting materials for other
potential ceramics such asboron
carbonitrides.

9. POLYBORAZYLENE HAS BEEN PROPOSED AS A RECYCLED HYDROGEN
STORAGEMEDIUM FORHYDROGEN FUEL CELLVEHICLE APPLICATIONS,
USING A "SINGLE POT" PROCESS FOR DIGESTION AND REDUCTION TO
RECREATE AMMONIA BORANE.
AMONG OTHER B-N TYPE COMPOUNDS MIXED AMINO -NITRO
SUBSTITUTED BORAZINES HAVE BEEN PREDICTED TO OUTPERFORM
CARBON BASED EXPLOSIVES SUCH AS CL-20