Aqueous polymerization of acrylic acid initiated by KMnO4 — H2C2O4 redox system

Misra, G. S.; Narain, Harish

doi:10.1002/macp.1968.021130106

Cited by 76 publications

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“…MISRA et aZ. [5][6][7] studied the homogeneous polymerization of acrylic acid, methacrylic acid and acrylamide in aqueous solution. At lower concentrations, the overall initial rate of polymerization is of the first order with respect to monomer and a t higher concentrations t o the square root of the initiator (KMn04) concentration.…”

Section: Introductionmentioning

confidence: 99%

Aqueous polymerization of methacrylamide initiated by KMnO₄/H₂C₂O₄ redox system

Misra

Gupta

1972

Makromol. Chem.

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The polymerization of methacrylamide initiated by potassium permanganate/oxalic acid redox system has been studied at 35 f 0.2"C in a nitrogen atmosphere. The rate of polymerization is independent of the activator (oxalic acid) concentration within the range 5.10-3to 10.10-3mole.1-1, except at very high (above 10.10-3mole.1--1) or at very low(be1ow 5 .lO-3 mole.1-1) concentrations of the activator. The rate varies linearly a t low monomer concentration (up t o 5.87.10-2 mole.1-1). The catalyst exponent decreases from nearly unity (0.91) to 0.66 with increase in concentration of the catalyst (KMnO4) probably due to participation of primary radicals in the termination of the growing chain. The addition of strong acid (HzSO4) within the range 5~10-4-15~10-4mole~l-~, shows a constant pH of 2.7 resulting in no change in initial rate. With activator alone (13zC204.2HzO), within the pH range 2.7 to 2.9 an optimum is observed. The initial rate increases with increase in polymerization temperature. The overall energy of activation as calculated from the ARRHENIUS plot has been found t o be 15.1 kcal.mole-1 within the temperature range 30-50°C.Organic solvents (water miscible only) depress the initial rate and the maximum conversion. Small amounts of neutral salts (KCl and NazSOd), however, show no appreciable effect on the polymerization rate, but small amounts of manganous salts (MnS04) can increase the initial rate to a considerable extent. High concentrations of MnS0.q result in termination of the growing chain. A complexing agent, Na2F2, decreases the initial rate but increases the maximum conversion. Introduction of fresh catalyst at intermediate stages of polymerization increases both the rate of the reaction and the conversion. ZUSAMMENFASSUNG:Die mit dem Redoxsystem Permanganat/Oxalsaure ausgeloste Polymerisation von Methacrylamid unter Stickstoff wurde bei 35 i 0,2OC untersucht. Die Polymerisationsgeschwindigkeit ist im Bereichvon 5.10-3 bis 10.10-3 mol.Z-1vonder Aktivator(Oxa1saure)konzentration unabhangig. Hiervon ausgenommen ist der Bereich sehr hoher (iiber 10 mol. I-1) oder sehr niedriger (unter 5 .10-3 mo1.Z-1) Alrtivatorkonzentration. Die Geschwindigkeit ist bis zu 5,87.10-2 mol. Z -1 der Monomerkonzeutration proportional. Der Katalysatorexponent nimmt von nahezu eins (0,91) bis auf 0,66 mit zunehmender Katalysator-(KMn04-)konzentration ab, da moglicherweise Primarradikale am Abbruch der wachsenden Kette teilnehmen. Das Zugeben einer starken Saure (HzSO4) innerhalb 5.10-4-15.10-4 mo1.I-1 ergibt einen koustanten pH-Wert von 2,7 und bewirkt keine Anderung der Startgeschwindigkeit. Mit dem Aktivator (IIzC204.2 HzO) allein wird im pH-Bereich von 2,7 bis 2,9 ein Optimum beobachtet. 195 C;. S. MISRA and C. V. GUPTA Die Startgeschwindigkeit wachst mit zunehmender Polymerisationstemperatur. Die gesamte Aktivierungsenergie berechnet sich im Bereich von 30-50 "C aus der Auftragung nach ARRHENIUS zu 15,l kcal.mo1-1. Organische Losungsmittel (nur solche, die mit Wasscr mischbar sind) vermindern die Startgeschwindigkei...

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Section: Introductionmentioning

confidence: 99%

Aqueous polymerization of methacrylamide initiated by KMnO₄/H₂C₂O₄ redox system

Misra

Gupta

1972

Makromol. Chem.

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“…The experimental setup and kinetic procedure were similar to that of our earlier reports and other work published elsewhere 9–12…”

Section: Methodsmentioning

confidence: 73%

Effects of surfactants on acrylonitrile polymerization initiated by a Cr(VI)–cyclohexanone redox system: A kinetic study

Behera

Sinha

2003

J of Applied Polymer Sci

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ABSTRACT:The polymerization of acrylonitrile (AN) was kinetically studied with a Cr(VI)-cyclohexanone (CH) redox system as an initiator from 25 to 45°C in the presence of a surfactant. The rate of polymerization and the percentage of the monomer conversion increased as the concentration of the anionic surfactant [sodium dodecyl sulfate (SDS)] increased above its critical micelle concentration. However, the cationic surfactant (cetyltrimethylammonium bromide) reduced the rate considerably at higher concentrations, whereas the nonionic surfactant (TX-100) had no effect on the rate. The effects of the Cr(VI), CH, AN, and H ϩ concentrations and the ionic strength on the rates were also examined. The presence of 0.015M SDS reduced the overall activation energy of the polymerization by 5.55 kcal/mol with respect to that in the absence of the surfactant. With increasing SDS concentration, the viscosity-average molecular weight also increased. A suitable mechanistic scheme was proposed for the polymerization process.

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“…It is obvious from Table 1 that the initial rate as well as the limiting conversion remains nearly constant over a certain range of oxalic acid concentration (4.5 .lo-3 to 7.5 -10-3 mole/].) 13) in the polymerization of acrylic acid initiated by this system. Similar observations have been made by MISRA et a1.…”

Section: Rate Dependence On Activator Concentrationmentioning

confidence: 80%

Aqueous polymerization of methacrylic acid initiated by permanganate/oxalic acid redox system

Misra

Narain

1968

Makromol. Chem.

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The polymerization of methacrylic acid initiated by permanganate / oxalic acid redox pair has been studied in aqueous media a t 30 & 0.2OC in nitrogen atmosphere.The initial rate of polymerization has been found to be proportional to nearly the first power of the catalyst (KMnO4) concentration ((0.8-6.0).10-4 mole/l.) a t low monomer concentration (5.89.10-2 mole/l.) but the catalyst exponent varies from 1.2 to 0.2 a t comparatively high monomer concentration (17.68.10-2 mole/l.) and falls a t comparatively higher concentrations of the activator ((C0OH)z) a t constant concentration of catalyst (1.6.10-4 mole/l.) and monomer (5.89.10-2 mole/l.). The rate is proportional to the first power of the monomer concentration within the range (2.36-14.1).10-2 mole/l. and catalyst (2.8.10-4 mole/l.).The initial rate increases with increase in polymerization temperature up to 45OC. The overall activation energy has been found to be 9.87 kcal/mole within the temperature range 30-45OC.Organic solvents (water miscible only) and salts (KCl, N a~S 0 4 and NazCz04) depress the rate considerably but the manganous salt (MnS04) is found to increase the initial rate. A complexing agent, NaF, decreases the rate as well as the maximum conversion.Introduction of new catalyst at intermediate stages of polymerization increases the rate and the maximum conversion. ZUSAMMENFASSUNG: Die in waBriger Losung durch das Redoxsystem Permanganat/Oxalsaure ausgeloste Polymerisation von Methacrylsaure wurde bei 30 rt 0,2OC und unter Stickstoff untersucht. Bei niedriger Konzentration des Monomeren (5,89.10-2 mol/l) ist die Anfangsgeschwindigkeit nahezu von erster Ordnung beziiglich der Katalysatorkonzentration ([KMn04] = (0,8-6,0).104 mol/l). Bei hoherer Monomerkonzentration (17,68.10-2 mol/l) schwankt der Exponent der Katalysatorkonzentration zwischen 1.2 und 0.2 ; aunerdem fillt er in diesem Falle mit zunehmender Konzentration des Aktivators (Oxalsaure), wenn die Katalysatorkonzentration (1,6 .lO-4 molll) und die Monomerkonzentration (5,89 molll) konstant gehalten werden. Bei der Katalysatorkonzentration 2.8 .lO-4 mol/l ist die Anfangsgeschwindigkeit der ersten Potenz der Monomerkonzentration proportional, und zwar im Bereich (2,36-14,1).10-2 mol/l. Mit zunehmender Temperatur steigt die Polymerisationsgeschwindigkeit an ; die Aktivierungsenergie ist zwischen 30 und 45 O C 9,87 kcal/mol. Mit Wasser mischbare organische Losungsmittel und auch Salze (KCl, NazS04, Na2C204) setzen die Reaktionsgeschwindigkeit her& ; MnS04 beschleunigt die Reaktion. NaF, 234 Polymerization of Methacrylic Acid by Permanganate/ Oxalic Acid Redox System das als Komplexbildner wirkt, senkt sowohl die Reaktionsgeschwindigkeit als auch den maximalen Umsatz. Ein Zusatz von frischem Katalysator im spiiteren Verlauf der Polymerisation erhoht sowohl die Reaktionsgeschwindigkeit als auch den maximalen Umsatz.

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Aqueous polymerization of acrylic acid initiated by KMnO₄ — H₂C₂O₄ redox system

Cited by 76 publications

References 18 publications

Aqueous polymerization of methacrylamide initiated by KMnO₄/H₂C₂O₄ redox system

Aqueous polymerization of methacrylamide initiated by KMnO₄/H₂C₂O₄ redox system

Effects of surfactants on acrylonitrile polymerization initiated by a Cr(VI)–cyclohexanone redox system: A kinetic study

Aqueous polymerization of methacrylic acid initiated by permanganate/oxalic acid redox system

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Aqueous polymerization of acrylic acid initiated by KMnO4 — H2C2O4 redox system

Cited by 76 publications

References 18 publications

Aqueous polymerization of methacrylamide initiated by KMnO4/H2C2O4 redox system

Aqueous polymerization of methacrylamide initiated by KMnO4/H2C2O4 redox system

Effects of surfactants on acrylonitrile polymerization initiated by a Cr(VI)–cyclohexanone redox system: A kinetic study

Aqueous polymerization of methacrylic acid initiated by permanganate/oxalic acid redox system

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Aqueous polymerization of acrylic acid initiated by KMnO₄ — H₂C₂O₄ redox system

Aqueous polymerization of methacrylamide initiated by KMnO₄/H₂C₂O₄ redox system

Aqueous polymerization of methacrylamide initiated by KMnO₄/H₂C₂O₄ redox system