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Separation and gravimetric determination of palladium (II) with 3-acetyl-6-methyl-2,4-pyrandione
Separation and t&pyrandione
gravimetric
determination
of palladium(l1)
pith
3 -acetyM-methyl-
During a study of pyrone derivatives as analytical reagents, 3-nitroso-4hydroxycoumarin, or oximidobenzotctronic acid, was reported as a sensitive and selective gravimctric reagent for palladium in the prcscncc of other metals including the platinum metals’*2 even when the platinum metals arc present together’. Further investigations have shown that 3-acctyl-6-methyl-2,4-pyrandionc (dehydroacctic acid) gives a pale yellow flocculent precipitate with palladium(lI), the precipitation of palladium being complete in cu. 1 h over the pH range 0.7-5.0. After being dried at 105-l lo”, the precipitate corresponds 10 the composition Pd(CgH,04)2.2H20, whereas at 140-15o”, the anhydrous complex is formed. Dehydroacctic acid can bc used for the separation and gravimetric dctcrmination of palladium(lI) in prcscncc of Cu(II), Ni(II), Au(III), Ag(I), F c and the platinum metals. even when the platinum metals arc present together. Experiwwtttul Reu~~ettts. Dchydroacetic acid (sodium salt) (Light & Co., England) was used without further purification as an aqueous I ‘x, (w/v) solution. Stock solutions of palladium(l I) were prepared as dcscribcd earlier ‘. The platinum metal salts wcrc obtained from Johnson, Matthcy & Co. ; other salts used wcrc of analytical-rcagcnr grade (BDH or Merck). Hydrochloric acid, nitric acid and sodium hydroxide wcrc used for pH adjustment, with LLBeckman Zeromatic pH meter. Procedure. To ca. 50 ml of aqueous palladium(l1) solution containing 1.5-17.5 mg of palladium at pH 1.5-2.0 at room temperature (20-300). add with stirring 4 mg of sodium dehydroacctatc per mg of palladium. as a 1 “A, solution. The solution becomes turbid and a pale yellow prccipitatc appears. Keep the solution at room tcmpcrature for about 1 h with occasional stirring to complctc the precipitation of palladium dchydroacctate, and filter through a wcighcd sintcrcd glass (G3) crucible. Wash the precipitate with cold water until free from chloride and nitrate ions. Dry at 105-110” for 3 h and weigh as Pd(C,H,04)2.2H10; or dry at 140-1600 for 1 h and weigh as Pd(CHH,0j)2. Results The results of some of the experiments involving diffcrcnt quantities of paltadium(I1) arc given in Table I. Amounts of paltadium(I1) more than 17.5 mg wcrc not determined, as the precipitate was very voluminous. The composition of the precipitate remained constant over the tcmpcraturc range 105-l 15” and then over the range 140-l SO”, corresponding to the dihydrate and the anhydrous complexes, rcspcctively. Drying at 105-l lo” required cu. 3 h for attainment of constant weight, hence the range 140-1800 was sclcctcd for routine work. Encr ofpH. Paltadium(t I) could bc accurately dctcrmincd in solutions ranging from 0.20 M in hydrochloric, nitric or sulphuric acids lo pH 5.0 (Table I I). At high& pH the complex decomposed to give the hydrated oxide. Am/.
Chim.
Actu.
54 ( I97
I ) 18 I -I 84
182
SHORT COMMUNICATIONS
TABLE
I
IX3’EHMINATION
fd(Il) rtrkcn
01: I’ALLAIXU.W(II)
Pd(f/)
Dlflerencc
Pd(lf)
Complex
jottnd
bw)
cuken
ohtulned
hl)
(w)
--
(WI)
__-._---
(mu)
Dried 01 140-16~ 1.47 6.20 2.94 12.70 5.88 25.60 1 I .I5 51.00 17.53 76.60
-t 0.02 - 0.02 0.w - 0.02 +O.OI
1.49 2.92 5.88 Il.73 17.54
__-
Pd(ll) :
found 04
I .43 2.93 5.90 11.75 17.55
Diflerencc
bw)
- 0.04 - 0.01’ + 0.02’ 0.w -+ 0.02
or 4 results. II
EFI:CCT01: pH (Weight
ACII)
ohruincd
DricJ al IO5- I IO” 1.47 7.00 2.94 13.75 5.88 27.70 II.75 55.50 17.53 83.15
TABLE
I>EttYl~I~OACI?lIC
. Complex
(“‘Y) --_
’ Avcrngc
WlTtl
ON
Tltt?
of Pd tukcn
I’Hl2CIPITATION
01’
I’ALLAI~IUM(~~)-~~~~~YD~~OACI~ATI!
= 5.88 mg) ---------
pt-t or acidity Pd(ll) found (nlg)
0.60 N I .22
0.40 N 2.86
0.20 N 5.89
0.05 N 5.86
1.7 5.88
PH Pd(ll)
5.0 5.90
5.5 5.28
5.8 4.02
6.2 3.32
6.6 1.49
found
(mg)
2.5 5.89
3.5 5.87
4.3 5.84
Separation of palladium(I1) from other ions With dehydroacetic acid at pH 1.5-2.0, palladium(II) could be successfully separated and determined in the presence of many anions and cations (Table III); up to 20-fold amounts of platinum(IV) and lOfold amounts of ruthenium(III), rhodium(III), osmium(IV), iridium(IV) and gold(II1) were tolerated. Iodide, cyanide, EDTA, cerium(IV) and uranium(V1) ions interfered. TABLE
Ill
I>IETTIIHMINhTION
01:
I’ALLAIXUM(II)
IN
PKI’SI!NCt?
.---Forei(l~l
lotI
rokot
Pc/(lf)
(w)
-
Acctatc
22.3 173.2 33.4 153.6 19.2 193.6 42.3 183.8 90.3 199.5
Tartmtc Citrate Foxir1utc
Ann/.
Chirn.
01:
I~OH~IGN
IOSS
---.---
Acfa. 54 (1971)
(mu) ---.-~
Tuktw
Fouttd
DiJJbence
5.875
5.863 5.887 5.850 5.875 5.887 5.887 5.863 5.900 5.900 5.900
0.012 0.012 0.025 o.cwO 0.012 0.012 0.012 0.025 0.025 0.025
181-184
SHORT
COMMUNICATIONS
PO: -
IS.4 175.8 12.8 195.6 10.1 20.2 10.4 20.8 19.2 38.4 19.3 38.6 19.5 39.0 44.0 97.5 9.7 19.4 27.U 13.2 84.7 II.3 91.3 Il.3 89.9 23.2 93.3 22.7 129.3 5.2 112.3 11.3 98.3 5.9 76.1 Il.2 102.3 32.7 113.3 23.4 132.9 27.2 192.3 28.0 143.7 42.3 108.4 11.2 97.8
BO;Ru(ll1) Rh(llI) Os(IV) Ir(lV) Pl(IV)
Au(ll
I)
Fc(l I) Fc(lll) Co(lI) Ni(lI) Zn(lI) AB(~) Ph(ll) Hy(lI) Cu(l I) Cd(ll) Cr(lII) Mo(VI) As(V) Sb(l II) Sn(ll)
183
4.406
3.368
4.406
3.828’
4.406
5.875
4.406
4.431 4.394 4.4 18 4.394 3.388 3.348 3.375 3.351 3.363 3.363 3.388 3.37s 3.363 3.388 3.375 3.375 3.375 3.363 3.388 4.43 1 4.418 4.418 4.381 4.43 1 4.418 4.394 4.394 4.406 4.418 3.838 3.814 3.814 3.814 3.826 3.851 4.418 4.43 I 4.418 4.418 5.887 5.863 5.900 5.875 5.887 5.863 4.394 4.381 4.418 4.394
0.025 0.012 0.012 0.012 0.020 0.020 0.007 0.017 O.OQS 0.005 0.020 0.007 0.005 0.020 0.007 0.007 0.007 0.005 0.020 0.025 0.012 0.012 0.025 0.025 0.012 0.012 0.012 O.OOO 0.012 0.010 0.014 0.014 0.014 0.002 0.023 0.012 0.025 0.012 0.012 0.012 0.012 0.025 0.000 0.012 0.012 0.012 0.025 0.012 0.012
’ As nitratc.
And.
C/aim. Acru, 54(1971)
181-184
184
SHORT
COMMUNICATIONS
Detertnirtatkxr VJ palladium(I I) in presence oj’ other noble metals In natural deposits, palladium is present along with other noble metals, hence the determination of palladium(I1) in presence of the other noble metals, was also invcstigatcd. With synthetic mixtures, palladium(l1) was successfully dctcrmined even in prescncc ofabout 40-fold amounts ofother noble metals when present together (Table IV). -rAnLli Iv _-. .
_. *r&w1 _
(w{/) _.
_
_ Hu(//l)
I’(/( II)
. ._,_. .._
5.07 IO. I 4 20.2x 18.2 I IO.14 50.70 __.-.-
3.37 4.40 3.37 4.40 2.94 5.HH ._- .-__--
’ Weight
ratio
.- .,,
-._ Os(fY)
. .._.
The author
rloblc
/r(/V)
mctnls
..-__
.
i’r(/V)
._-- _..--. 4.H5 19.50 9.70 39.00 19.40 58.50 14.55 29.25 19.40 39.00 9.70 19.50 . .. . _-.--.
_ .____
-
4.HO 9.60 14.40 19.20 24.00 9.60 __-.-_.-.
-- ..-
_ 20 24 40 22 48 I9 .._-_
3.39 4.40 3.35 4.44 2.9x 5.92
-..
to Prof. B. D. Jain, Department help and suggestions.
14th October
1970)
,l!Ict/. C’/li0,. AcYtJ. 54 (197 1) l xl - 1x4
. .- -.
ofChcmistry,
I G. S. MANK~;. A. N. 13tlh.r ,\rw 13. D. JAIN. Arrtrl. C/tir,r. Acrtr. 39 (1967) 369. 2 G. S. MANKU. A. N. BIIAT AND U. D. JAIN. Tcrlrtrrrtr. I6 (1969) 1421.
(Rcccivcd
Pt/(//)
DiJJ.
Jtiitrd
/ll~(///)
.--.....
.-__ ___.._____
_ ---. (PUN)
.
.
(w)
,. ._____
._ .-
0.02 0.00 0.02 0.04 0.04 0.04
_ ._--____
to Pd(ll).
is grateful
of Delhi. for his valuable
.
. _
IO.40 24.00 14.40 20.80 5.20 19.20 IO.40 9.60 IS.60 19.20 20.80 4.80 ._.. -..__.--__.-----._--
of other
___-- .._........_..__. HiIfi0~
/
. _
- ___.._
University
gravimetric
determination
of palladium(l1)
pith
3 -acetyM-methyl-
During a study of pyrone derivatives as analytical reagents, 3-nitroso-4hydroxycoumarin, or oximidobenzotctronic acid, was reported as a sensitive and selective gravimctric reagent for palladium in the prcscncc of other metals including the platinum metals’*2 even when the platinum metals arc present together’. Further investigations have shown that 3-acctyl-6-methyl-2,4-pyrandionc (dehydroacctic acid) gives a pale yellow flocculent precipitate with palladium(lI), the precipitation of palladium being complete in cu. 1 h over the pH range 0.7-5.0. After being dried at 105-l lo”, the precipitate corresponds 10 the composition Pd(CgH,04)2.2H20, whereas at 140-15o”, the anhydrous complex is formed. Dehydroacctic acid can bc used for the separation and gravimetric dctcrmination of palladium(lI) in prcscncc of Cu(II), Ni(II), Au(III), Ag(I), F c and the platinum metals. even when the platinum metals arc present together. Experiwwtttul Reu~~ettts. Dchydroacetic acid (sodium salt) (Light & Co., England) was used without further purification as an aqueous I ‘x, (w/v) solution. Stock solutions of palladium(l I) were prepared as dcscribcd earlier ‘. The platinum metal salts wcrc obtained from Johnson, Matthcy & Co. ; other salts used wcrc of analytical-rcagcnr grade (BDH or Merck). Hydrochloric acid, nitric acid and sodium hydroxide wcrc used for pH adjustment, with LLBeckman Zeromatic pH meter. Procedure. To ca. 50 ml of aqueous palladium(l1) solution containing 1.5-17.5 mg of palladium at pH 1.5-2.0 at room temperature (20-300). add with stirring 4 mg of sodium dehydroacctatc per mg of palladium. as a 1 “A, solution. The solution becomes turbid and a pale yellow prccipitatc appears. Keep the solution at room tcmpcrature for about 1 h with occasional stirring to complctc the precipitation of palladium dchydroacctate, and filter through a wcighcd sintcrcd glass (G3) crucible. Wash the precipitate with cold water until free from chloride and nitrate ions. Dry at 105-110” for 3 h and weigh as Pd(C,H,04)2.2H10; or dry at 140-1600 for 1 h and weigh as Pd(CHH,0j)2. Results The results of some of the experiments involving diffcrcnt quantities of paltadium(I1) arc given in Table I. Amounts of paltadium(I1) more than 17.5 mg wcrc not determined, as the precipitate was very voluminous. The composition of the precipitate remained constant over the tcmpcraturc range 105-l 15” and then over the range 140-l SO”, corresponding to the dihydrate and the anhydrous complexes, rcspcctively. Drying at 105-l lo” required cu. 3 h for attainment of constant weight, hence the range 140-1800 was sclcctcd for routine work. Encr ofpH. Paltadium(t I) could bc accurately dctcrmincd in solutions ranging from 0.20 M in hydrochloric, nitric or sulphuric acids lo pH 5.0 (Table I I). At high& pH the complex decomposed to give the hydrated oxide. Am/.
Chim.
Actu.
54 ( I97
I ) 18 I -I 84
182
SHORT COMMUNICATIONS
TABLE
I
IX3’EHMINATION
fd(Il) rtrkcn
01: I’ALLAIXU.W(II)
Pd(f/)
Dlflerencc
Pd(lf)
Complex
jottnd
bw)
cuken
ohtulned
hl)
(w)
--
(WI)
__-._---
(mu)
Dried 01 140-16~ 1.47 6.20 2.94 12.70 5.88 25.60 1 I .I5 51.00 17.53 76.60
-t 0.02 - 0.02 0.w - 0.02 +O.OI
1.49 2.92 5.88 Il.73 17.54
__-
Pd(ll) :
found 04
I .43 2.93 5.90 11.75 17.55
Diflerencc
bw)
- 0.04 - 0.01’ + 0.02’ 0.w -+ 0.02
or 4 results. II
EFI:CCT01: pH (Weight
ACII)
ohruincd
DricJ al IO5- I IO” 1.47 7.00 2.94 13.75 5.88 27.70 II.75 55.50 17.53 83.15
TABLE
I>EttYl~I~OACI?lIC
. Complex
(“‘Y) --_
’ Avcrngc
WlTtl
ON
Tltt?
of Pd tukcn
I’Hl2CIPITATION
01’
I’ALLAI~IUM(~~)-~~~~~YD~~OACI~ATI!
= 5.88 mg) ---------
pt-t or acidity Pd(ll) found (nlg)
0.60 N I .22
0.40 N 2.86
0.20 N 5.89
0.05 N 5.86
1.7 5.88
PH Pd(ll)
5.0 5.90
5.5 5.28
5.8 4.02
6.2 3.32
6.6 1.49
found
(mg)
2.5 5.89
3.5 5.87
4.3 5.84
Separation of palladium(I1) from other ions With dehydroacetic acid at pH 1.5-2.0, palladium(II) could be successfully separated and determined in the presence of many anions and cations (Table III); up to 20-fold amounts of platinum(IV) and lOfold amounts of ruthenium(III), rhodium(III), osmium(IV), iridium(IV) and gold(II1) were tolerated. Iodide, cyanide, EDTA, cerium(IV) and uranium(V1) ions interfered. TABLE
Ill
I>IETTIIHMINhTION
01:
I’ALLAIXUM(II)
IN
PKI’SI!NCt?
.---Forei(l~l
lotI
rokot
Pc/(lf)
(w)
-
Acctatc
22.3 173.2 33.4 153.6 19.2 193.6 42.3 183.8 90.3 199.5
Tartmtc Citrate Foxir1utc
Ann/.
Chirn.
01:
I~OH~IGN
IOSS
---.---
Acfa. 54 (1971)
(mu) ---.-~
Tuktw
Fouttd
DiJJbence
5.875
5.863 5.887 5.850 5.875 5.887 5.887 5.863 5.900 5.900 5.900
0.012 0.012 0.025 o.cwO 0.012 0.012 0.012 0.025 0.025 0.025
181-184
SHORT
COMMUNICATIONS
PO: -
IS.4 175.8 12.8 195.6 10.1 20.2 10.4 20.8 19.2 38.4 19.3 38.6 19.5 39.0 44.0 97.5 9.7 19.4 27.U 13.2 84.7 II.3 91.3 Il.3 89.9 23.2 93.3 22.7 129.3 5.2 112.3 11.3 98.3 5.9 76.1 Il.2 102.3 32.7 113.3 23.4 132.9 27.2 192.3 28.0 143.7 42.3 108.4 11.2 97.8
BO;Ru(ll1) Rh(llI) Os(IV) Ir(lV) Pl(IV)
Au(ll
I)
Fc(l I) Fc(lll) Co(lI) Ni(lI) Zn(lI) AB(~) Ph(ll) Hy(lI) Cu(l I) Cd(ll) Cr(lII) Mo(VI) As(V) Sb(l II) Sn(ll)
183
4.406
3.368
4.406
3.828’
4.406
5.875
4.406
4.431 4.394 4.4 18 4.394 3.388 3.348 3.375 3.351 3.363 3.363 3.388 3.37s 3.363 3.388 3.375 3.375 3.375 3.363 3.388 4.43 1 4.418 4.418 4.381 4.43 1 4.418 4.394 4.394 4.406 4.418 3.838 3.814 3.814 3.814 3.826 3.851 4.418 4.43 I 4.418 4.418 5.887 5.863 5.900 5.875 5.887 5.863 4.394 4.381 4.418 4.394
0.025 0.012 0.012 0.012 0.020 0.020 0.007 0.017 O.OQS 0.005 0.020 0.007 0.005 0.020 0.007 0.007 0.007 0.005 0.020 0.025 0.012 0.012 0.025 0.025 0.012 0.012 0.012 O.OOO 0.012 0.010 0.014 0.014 0.014 0.002 0.023 0.012 0.025 0.012 0.012 0.012 0.012 0.025 0.000 0.012 0.012 0.012 0.025 0.012 0.012
’ As nitratc.
And.
C/aim. Acru, 54(1971)
181-184
184
SHORT
COMMUNICATIONS
Detertnirtatkxr VJ palladium(I I) in presence oj’ other noble metals In natural deposits, palladium is present along with other noble metals, hence the determination of palladium(I1) in presence of the other noble metals, was also invcstigatcd. With synthetic mixtures, palladium(l1) was successfully dctcrmined even in prescncc ofabout 40-fold amounts ofother noble metals when present together (Table IV). -rAnLli Iv _-. .
_. *r&w1 _
(w{/) _.
_
_ Hu(//l)
I’(/( II)
. ._,_. .._
5.07 IO. I 4 20.2x 18.2 I IO.14 50.70 __.-.-
3.37 4.40 3.37 4.40 2.94 5.HH ._- .-__--
’ Weight
ratio
.- .,,
-._ Os(fY)
. .._.
The author
rloblc
/r(/V)
mctnls
..-__
.
i’r(/V)
._-- _..--. 4.H5 19.50 9.70 39.00 19.40 58.50 14.55 29.25 19.40 39.00 9.70 19.50 . .. . _-.--.
_ .____
-
4.HO 9.60 14.40 19.20 24.00 9.60 __-.-_.-.
-- ..-
_ 20 24 40 22 48 I9 .._-_
3.39 4.40 3.35 4.44 2.9x 5.92
-..
to Prof. B. D. Jain, Department help and suggestions.
14th October
1970)
,l!Ict/. C’/li0,. AcYtJ. 54 (197 1) l xl - 1x4
. .- -.
ofChcmistry,
I G. S. MANK~;. A. N. 13tlh.r ,\rw 13. D. JAIN. Arrtrl. C/tir,r. Acrtr. 39 (1967) 369. 2 G. S. MANKU. A. N. BIIAT AND U. D. JAIN. Tcrlrtrrrtr. I6 (1969) 1421.
(Rcccivcd
Pt/(//)
DiJJ.
Jtiitrd
/ll~(///)
.--.....
.-__ ___.._____
_ ---. (PUN)
.
.
(w)
,. ._____
._ .-
0.02 0.00 0.02 0.04 0.04 0.04
_ ._--____
to Pd(ll).
is grateful
of Delhi. for his valuable
.
. _
IO.40 24.00 14.40 20.80 5.20 19.20 IO.40 9.60 IS.60 19.20 20.80 4.80 ._.. -..__.--__.-----._--
of other
___-- .._........_..__. HiIfi0~
/
. _
- ___.._
University