SUMMARY
StJt-!MARY
'lb.e work presented i n the thcts1s is divided into tvo
parts.
Pa r t 1 presents resul ta on the ldne t1cs ot isotope
exchange reaction betvean 1od1de and iodate lons stu-:1- 1ed by
paper ohromatographJ.
The reaotlon proce ds at a measurable rate at bigb
\•peraturQs 1n the range 100·300" C.
The exohan.go being
wholl y quenched at room tampera,ure, 1t appeared teas1ble to
empl oy paper chromatography 1n order to tollow i t s progress.
Aaatal.Jag that there i s no 1sotop1o eftgot,
k1t~•tie
or
thermodynamic between 131 1 (halt-life A.04 d8JS) and ordtnarr
iodine 127 r, th• 1od1da -:;yst• van labelled with 131 1 and the
reaction vas s tudied under an inert ataospbere
by varying
one
of the tollow1ng paraeters &t a tiae keeplft« the oth•rs eon~ tanta
(1) Concentration ot the I. and 103 tons separately as vell as
concurrently, ( 2) addition
suCh a s Cl-, NOj and
'lbe rate ot
so;·,
or
iodine and other fbPeign tons
(3) pHt and (4) tesp erature.
exehan ~e
R vas obtained by ua1ng th.e 'i cKay
relat1on and the rate eoftstant 1t was calculated tl'OIIl the relation
k • R/,1-)(IOa)•
It 1s observed that all the reaetlon rates
tol Low the general t1rs t order exchange and the rate as weU as
the rate constant are 1nfl u ncGd by all th
1nto account.
var iables taken
- 1 22 -
Foll owing
(1)
re the cbiet f indings:
As the eoncent rat1on i s steadily inc -
s d , th
k valu
1
=
eith r constant (when eone1cone10- ) or 1nor.aa tlll the
3
oono ntratlon or ions reaches a bout 0 . 2 to 0 . 3 M (k ep1n g either
eonoz- or conc 10 - constant equal to o. a
or
3
M) 1
tor fUr ther 1neraa
concentration, k diminishes t ast i n all the systems .
( 2)
or
Traces
sy&t
f r ee i odine are tomed invariably in all the
s studied except ln
found to be much maller.
aore
l knl1ne media Vberein t he
Furth er , a
d more iodine 11 liborat d as
th
ates are
r action proc eds
bserv d speetrophoto-
A v ry pronoune d increas e ( 2 t o 5 t1mos) i n
metrically.
exeh ng r te was found due to the addi tion of iodine ven i n
millimolar aoneentrattons .
(3) Presence
or
chloride , nitrate and sulpbate ions at 0 .1 M
concentrati ons suppresse
Cl• > NOj
(4)
ot
by t
xchange ?at
ln the order
> so;·.
Th Arrhenius pl ot shows thr e disti nct regi ons
a char
Thi
the
~ter1st1c
enern of actiY t1on as follows:
~
T
(a)
E
42 Kcal/mole when
(b)
:£ ~ 13 Koal/mole 'When
(c)
~ ~
88 Kcallmole when
< 500
K
ooo• < T < 530"K
T > soo ~ K .
indica tes tha t the reaction 1s a compoalt
··o or more concurrent reactions each diff er
per ture.
ch w1th
and
one , made up
tly l nfiuencecl
- 123 (5)
A finding ot pa t1eul r 1ntere t 1s 1n r egard to the
a urable 1n4uat1on periOds ot the os-d
1n s
extr • o s s .
so
vh
th tl\
the r
or 1n
~1
all
t1ons and
.I t is pract1e l ly z ro
r e en.,e ot
tud1ed ln tb
dded i odine
tly acidic m d1um .
The Vbol
pi cture or the
principal r
0 . 5 to 5 hour
c · nt coneent
o ot temperatur •
ot1on w
or
l n g neral, the lnduetlon p r1od
s s with the 1nerease ot r
dec
I'
xebange reaction tbus turn1sh s a c plex
obanim i nvolved and 1 t i s thought that t he
ot1on
xo; . . I •-
;:
[o -
.,o.. . . •] a-
~~;I
•• (1)
l owe t , controls the r t e of (ov rall) exchange . 'fb1s
beln
1 followed by t h other cons cut1•• t st
Th
tollows:
reactions propo ed are
conaecut1
etlons .
(3)
I • 0 + + a o __,. I • 0 3
2
2
(OII )3- + sa• _...,. I ,2
d
t'h
r
tas t r
t 1rat ord r
the abov
th
etions
nu+
~ ..
+
r:-
nd the obs noed o
t h re peot to e1 the? I
ehanla
+
-
•• ( 3 )
+
H o
2
..
rall
•• (4)
t e fo l low
or IO3 cone en t r t l on .
&1. o explains the obs•Pfed tt ots due to
1 a 1n pH , coneentrat1ons and impurities .
- 124•
Part w2 ot the thesis pr esents r esult
r coil
on the Cn,Y)
actions in org nio halogen compounds
and t he oollaction
ot charged active products on th silver leetrodes .
· eot19n I;
In thi s secti on an exportm
tor
tal techni que
as developed
pplying an electric t1 ld t o coll ct the products ot
(n,Y)
d1olys1s during
1r~
d1· t1on.
The syst s s tudied were
met hyl , ethyl and phenyl iodides and othyl and phenyl bromides.
e wer 1rr di a ted 1n a
r got o 11, containing demoun
1 24sb-He photoneutron ource ot 13 curi e
lectrodes , by
~1e
(n
n ux
about 107 cm· 2sec· 1 > applyi n g
800 V/ cm d. e.
constant potentia l
The total acti vit y produe d 1n t he liqui d and
tbe tractions of t h
ctive
ohar ~ e d
anode and t he c thode pl at es ver
1n tb
ble
p rtielas collect1
e su ed ,
s
on the
lso the chans s
elect rical conductance 1n the irradiated sys t em •
Results showc
(1)
th po lt1voly and negativel y charged active species are
produced and collect on the pl ates , the anodlc
ct1v1ty always
reater than the Ot\ t bod1o.
( 2)
less th n 30 per e
t
or th
tt)tal aot1w1t y collects on
tho plates wh n the fracti on of the liquid under the el ectrto
field 1 13 per cent.
( 3)
in the oaso ot ethyl iodide, as t he p r lod or 1rr diatlon
1ncrea
a the
tlo
or
t ho anodi c to tho cathodic yi eld , which
- 1
-
always gre ter t han one, :lncreas
1
nd tb
d
gain to 1.3 tol' saturation periods ot
1n1shes
It ts also observed that the traction of th
lrr d1 t1on.
aet1v1ty eolt et1ng on thf.t eh
upto bout 50 minutes
to be expect ed .
n char
~
total
d plates goes on 1nc:rea 1ng
slowly; the tot l
10 s on 1ne:aeas1ng with time as 1
The lno:rease la expla1Ded on the bas is of
t rans fers bet
inactive charged sp c1es
produced mostly by the 1nt ens
ap ci s ere t d 1n th
to be du
~
d then d crease
ac t1 1ty produced otcours
o
to a maximum ot abOut 2
to th
Y- tlux
Cn,Y) eventJ
d ctlve unoh r ed
decreas
1s exp eted
polari zation of the electrodes by tho products
or rad1ol ys1s .
( )
th
total
cttvi t y colleet1n on t he el etrode ,
r tio ot the anodic to cathodic yi eld , ar
order
or
t he R-X bond trength 1n the dift r
s w 11 as
in the r · r se
t
bromo and 1od
tudted .
oo
un is
(6)
a pr limln ey stUdy o r the change ln con(1uct1v1ty due to
r d1olysi s
sbo~~
b . ide Whi h hav
maximum lnore se tn ethyl iodide and etb7l
relat1Yely h1 h r d1 leotrlc constants .
PJOb bl r actions
r
discussed to aceount tor the
Yartous r sulta.
@tatlop, Its
pl s ot chloroform and e r bOn t t chloride were
used tor 1rrad1at1on t a dose r t 3 x 1013 4 a.s x 1013
Pur
oond !'Gspaet1voly.
obse!"Yat1onst
eV/ ml per s
llow1ng at"e t he maj or
- 126(l)
Retention or th
v ry r pi <il.y on the
r ad1oact1Ye species in cc1 4 d craas s
d tion ot alc~J bol during 1n d1 tion.
( 2J Tb w t r-extr aet ot the i rradiated sampl s contains t wo
t y p s ot act1v1t1es , on
n1 tra t e aftd th
to
r
pp
chlor t
that c n be precipitated by silver
oth r which i s not thus pr eei p1 tated .
rs to b
dn to chlori de i ons and t h
Tb
l ater due to
tons obta ined tl'Om hnochlor1te, a 11 el y ini tial
roduct bes i des chloride i ons ln wat r layer .
(3)
~then
Both anodic and cathodic a ctlv1t1 s were obs
e field w s
ppl1 d dur i
w 11
tter th e il'l"adi a t i on ,
the anodic bei n g 1 , ys gr ea ter t han the ca tnod.1c.
(4)
Th
conductivity ot
l o rofon.'l falls r pidly within firs t
5-10 s conds on the applicati on of the f i el d
and t hen d cr a
of t
s
lowly .
This 1
tt r ir dia tloa
tt 1btttod to t h
pr sene
pped and quas1tr e el ctrons in the l i quid baring v ery
high mobility tmmedl tely r ach th
1n it1 1 currents a
obs erve-d .
el etrodew l e di ng to hi gher
This pl'Ocess being
oon ov r ,
the tlnal aonduotano 1 mainly due to t he hydrochlortc
produced 1n ehlorotorm durin
was obs rvable 1n the c s e
or
1rr di t1on.
c1d
No such phen
enon
e rbon t e tr chlorid , th
conductance in tb1s c se being be7ond th$ S$na1t1vity o f the
1ns trum nt (lea
th
than 4 x 10• 13 mho).
Cl acti vity was round ch t•g d
Ho
r , a tracti on ot
., lt oolloot d on the
lectrodes .
(6)
Thi s startin g v alue of conductance tall , 1 .t the t1 ld
- 127-
ap llc tlon ls d lay d,witb1n
s mtnut e after the irradiation.
This fall 1
sl
xpla 1n d on th
ot the trapp1
of quas1tt-ee
electrons 1n tho bulk or the liqUid 1f field 1a not applied
edi tely.
Th e electron o ptures produce ch r g
lower ob1l1ty.
'fh aot1111t7 coll otlnl on the
p oles ot
lates, when
con cted for the d cay, howev r, is constant upto atleast an
hour hovtng
or
w1 thin the cours
(6)
s th
that the
the~eb.r
1nt ns1ty
the
or
r
not ett1ng neutral ized
xperiaents •
the t1 ld 1s 1nore
d, more and
ore
act1 1ty eoll cts on th pl t es upto saturation and then
t
cur
t sho
tor turther increase.
a continuous 1nor
oonduot1v1t7 ot th
c 11 r
i.Jh11e the starting
•• with the tield, the
ohes a. uld..mum around 2000 V/cm
d tb n d1mtn1 hes.
A probabl
sequence
or
ttents 1
diseua ed vhieb
aecounts tb results (or section I and s ction II) qualitatively.