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Solvents for low-temperature phosphorimetry of nylon
SHORT
COMMUNICATIONS
437
$ Y. K. CIIAU AND I<. LUM-SHUE-CHAN, Anal. Chit)&. .dCla, 48 (1969) 205. 5. J. STAR+, The Solvent Bxfvacliort of Mcfal Cl~elatcs, Pcrgamon, NW- York, G R. A. MOSTYN AND A. F. CUNNINGIIAM, A~zal.Ckerrt.. 39 (1gG7) 433.
(Received
July 25th.
1969) .*Itrd.
Solvents
for
1964,pp. rGo-1GG.
low-temperature
phosphorimetry
Chirrt. Acln.
48 (xgGg)
434-437
of nylon
Two rather extensive lists of solvent behavior at low temperaturesl~” have proven extremely valuable to those engaged in phosphorimetry. However, for those interested in investigation of the phosphorescence of synthetic po.lymers, or impurities therein, this type of information has been very meager indeed. Altllough~ the present work was concerned primarily wit11 nylon solvents, some of the solvents will obiously be applicable to other polymers.
The quartz phosphorescence tubes and the clear liquid nitrogen standard American Instrument Co. equipment.
dewar
were
All solvents tested were reagent-grade chemicals, and were used without further purification. For a given application, such purification might well be necessary. The ethanol was 95% rather than “absolute”. Method
A small sample of each solvent was placed in each of three standard quartz phosphorescence tubes. Each of the tubes was plunged into a clear dewar containing liquid nitrogen, and subsequent behavior was observed. In all cases, the triplicate samples reacted identically.
The ideal solvent, in this case, should dissolve nylon in reasonable quantities at room temperature, and form a clear glass upon rapid cooling to 77°K. Of all solvents listed in the references cited, only sulfuric acid and phosphoric acid appeared very promising, and these had been tested in the 193~---213~I< range rather than at the more generally useful liquid nitrogen temperature of 77°K. These two were included in the present worlc along with several other powerful polymer solvents. The results of the experiments are shown in Table I. It is evident from these data that the only solvents tested which arc suitable for low-temperature phosphorimetry are phosphoric acid and formic acid-ethanol. All formic acid-ethanol mixtures listed are capable of room-temperature dissolution of reasonable amounts of nylon. Frozen phosphoric acid solutions containing IO g/l of nylon G6 exhibited slightly different phosphorescence behavior from frozen nylon fibers or films. Activation spectra in the two media were quite similar, but emission occurred at slightly shorter wavelengths in the glass, and the mean radiative lifetime was extended by Aural.
Cltim.
Acta,
48 (IO@)
437-438
SHORT
438
COMMUNICATIONS
about 30% over that for frozen fibers or films. It is not surprising that such effects were produced by the transition from a solid nylon environment to a highly acidic and relatively dilute frozen solution. Similar effects were observed for the formic acid-ethanol mixtures. This behavior causes no difficulty as long as its existence is borne in mind and no attempts are made to compare directly data measured from two clif ferent media.
Cont. sulfuric acid Cont. phosphoric acid I-lcxafluoroisoprop~~nol Trifluoroacctic ncicl Dichloroacctic acid Formic &cl, #So/o l?ormic acid : ethanol, Formic acid : ethanol, Formic &cl : cthnnol, Formic acicl : ethanol, l?ormic acicl : ethanol,
.
snow Clear glass, slightly Snow Snow Snow
snow 2:I 3:I 4:I 5:I
mixture mixture mixture mixture 6 : I mixture
crackecl
Clear glass, slightly Clear glass, slightly Clear glnss, slightly Snow Snow
cracked crackccl crackccl
ConczlLsiolbs
This investigation has shown that concentrated phosphoric acid and several mixtures of formic acid and ethanol are satisfactory solvents for low-temperature phosphorirnetry of nylon. Several other common polymer solvents have been found unsatisfactory. Clwmstra~zd Research P. 0. Box 731, J)zc71mwL,
N.
c.
27702
A 2d.
JOHNSON
(U.S.A)
I 1:.J . SMIUI, J. I<. Snlmr AND S. I?. MCGLYNN, Rev. Sci. Imlr., 33 (IgGz) 2 J, ID, WINEPORI)NER ANI) I?.A. ST. JOHN, Awd.Chew.,35 (1953) 2211.
(Received
L. D.
Center,
1370.
July zrst, IgGg)
CAinr. A cln, 48 (1969) 437-438
Selectivity in the synergetic extraction of cobalt(ll) and with a mixture of 2-thenoyltrifluoroacetone and pyridine
nickel(Il) bases
Synergetic effects of neutral ligands (B) in the extraction of cobqlt(II) and nickel(I1) with z-thenoyltrifluoroacetone (TTA) have already been investigated by several workersl-3. The authors have also suggested that the synergic extraction system is valid for the improvement of the spectrophotometric sensitivity in the determina.tion of these ions with TTA4-0. However, as far as the selectivity is concerned, the TTA methods for cobaN and nickel(I1) fi are still inadequate. Awd.
Cl&a.
Acta,
48 (1969) 438-441
COMMUNICATIONS
437
$ Y. K. CIIAU AND I<. LUM-SHUE-CHAN, Anal. Chit)&. .dCla, 48 (1969) 205. 5. J. STAR+, The Solvent Bxfvacliort of Mcfal Cl~elatcs, Pcrgamon, NW- York, G R. A. MOSTYN AND A. F. CUNNINGIIAM, A~zal.Ckerrt.. 39 (1gG7) 433.
(Received
July 25th.
1969) .*Itrd.
Solvents
for
1964,pp. rGo-1GG.
low-temperature
phosphorimetry
Chirrt. Acln.
48 (xgGg)
434-437
of nylon
Two rather extensive lists of solvent behavior at low temperaturesl~” have proven extremely valuable to those engaged in phosphorimetry. However, for those interested in investigation of the phosphorescence of synthetic po.lymers, or impurities therein, this type of information has been very meager indeed. Altllough~ the present work was concerned primarily wit11 nylon solvents, some of the solvents will obiously be applicable to other polymers.
The quartz phosphorescence tubes and the clear liquid nitrogen standard American Instrument Co. equipment.
dewar
were
All solvents tested were reagent-grade chemicals, and were used without further purification. For a given application, such purification might well be necessary. The ethanol was 95% rather than “absolute”. Method
A small sample of each solvent was placed in each of three standard quartz phosphorescence tubes. Each of the tubes was plunged into a clear dewar containing liquid nitrogen, and subsequent behavior was observed. In all cases, the triplicate samples reacted identically.
The ideal solvent, in this case, should dissolve nylon in reasonable quantities at room temperature, and form a clear glass upon rapid cooling to 77°K. Of all solvents listed in the references cited, only sulfuric acid and phosphoric acid appeared very promising, and these had been tested in the 193~---213~I< range rather than at the more generally useful liquid nitrogen temperature of 77°K. These two were included in the present worlc along with several other powerful polymer solvents. The results of the experiments are shown in Table I. It is evident from these data that the only solvents tested which arc suitable for low-temperature phosphorimetry are phosphoric acid and formic acid-ethanol. All formic acid-ethanol mixtures listed are capable of room-temperature dissolution of reasonable amounts of nylon. Frozen phosphoric acid solutions containing IO g/l of nylon G6 exhibited slightly different phosphorescence behavior from frozen nylon fibers or films. Activation spectra in the two media were quite similar, but emission occurred at slightly shorter wavelengths in the glass, and the mean radiative lifetime was extended by Aural.
Cltim.
Acta,
48 (IO@)
437-438
SHORT
438
COMMUNICATIONS
about 30% over that for frozen fibers or films. It is not surprising that such effects were produced by the transition from a solid nylon environment to a highly acidic and relatively dilute frozen solution. Similar effects were observed for the formic acid-ethanol mixtures. This behavior causes no difficulty as long as its existence is borne in mind and no attempts are made to compare directly data measured from two clif ferent media.
Cont. sulfuric acid Cont. phosphoric acid I-lcxafluoroisoprop~~nol Trifluoroacctic ncicl Dichloroacctic acid Formic &cl, #So/o l?ormic acid : ethanol, Formic acid : ethanol, Formic &cl : cthnnol, Formic acicl : ethanol, l?ormic acicl : ethanol,
.
snow Clear glass, slightly Snow Snow Snow
snow 2:I 3:I 4:I 5:I
mixture mixture mixture mixture 6 : I mixture
crackecl
Clear glass, slightly Clear glass, slightly Clear glnss, slightly Snow Snow
cracked crackccl crackccl
ConczlLsiolbs
This investigation has shown that concentrated phosphoric acid and several mixtures of formic acid and ethanol are satisfactory solvents for low-temperature phosphorirnetry of nylon. Several other common polymer solvents have been found unsatisfactory. Clwmstra~zd Research P. 0. Box 731, J)zc71mwL,
N.
c.
27702
A 2d.
JOHNSON
(U.S.A)
I 1:.J . SMIUI, J. I<. Snlmr AND S. I?. MCGLYNN, Rev. Sci. Imlr., 33 (IgGz) 2 J, ID, WINEPORI)NER ANI) I?.A. ST. JOHN, Awd.Chew.,35 (1953) 2211.
(Received
L. D.
Center,
1370.
July zrst, IgGg)
CAinr. A cln, 48 (1969) 437-438
Selectivity in the synergetic extraction of cobalt(ll) and with a mixture of 2-thenoyltrifluoroacetone and pyridine
nickel(Il) bases
Synergetic effects of neutral ligands (B) in the extraction of cobqlt(II) and nickel(I1) with z-thenoyltrifluoroacetone (TTA) have already been investigated by several workersl-3. The authors have also suggested that the synergic extraction system is valid for the improvement of the spectrophotometric sensitivity in the determina.tion of these ions with TTA4-0. However, as far as the selectivity is concerned, the TTA methods for cobaN and nickel(I1) fi are still inadequate. Awd.
Cl&a.
Acta,
48 (1969) 438-441