共查询到20条相似文献,搜索用时 31 毫秒
1.
Prashant V. Kamat Geneviève Sauvé Dirk M. Guldi Klaus -Dieter Asmus 《Research on Chemical Intermediates》1997,23(7):575-585
Pulse radiolysis and steady-state radiolysis experiments describing the radical and electron transfer reactions of C84 are reported here for the first time. C84 reacts readily with radiolytically generated chloromethyl (•CCl3) and trichloromethylperoxyl (CCl3OO•) radicals in CCl4. The formation of the radical adduct has been confirmed from its characteristic absorption in the UV (320 nm) and visible
(480 nm). Radical-induced oxidation in 1,2-dichloroethane (1,2-DCE) resulted in a short lived transient absorbing at 920 nm.
Reduction of C84 in toluene/2-propanol/acetone could be conveniently followed by formation of an absorption band with an absorption maximum
at 960 nm. 相似文献
2.
The •OH and the NO2
• radicals generated pulse radiolytically in N2O-saturated aqueous solution at pH 8–8.5 oxidize Mesna to form the corresponding thiyl radicals which on reaction with thiolate
ions form an RSSR•
− type of transient with λmax = 420 nm. The rate constants for the formation of these transients were determined. In the absence of O2 at pH=6, the RS• radicals formed show an absorption maximum at 360 nm and an ε=200±50 dm3 mol−1 cm−1. The rate constant k (•OH+RSH) was 6×109 dm3 mol−1 s−1 as determined from competition kinetics. In the presence of O2 the Mesna thiyl radical was seen to rapidly add oxygen to form an RSOO• type of species with λmax = 535 nm, ε=700±50 dm3 mol−1 cm−1 and k (RS•+O2)=1.3×108 dm3 mol−1 s−1. Both the RS• and the RSOO• radicals formed by the oxidation of Mesna were able to abstract H-atoms from ascorbate ions and k(RS• +AH−)=~k(RSOO•+AH−)=~6−7×108 dm3 mol−1 s−1-. Moderately strong oxidants like CCl3OO• and the (CH3)3CO• radicals, having a reduction potential of +1.4−1.6 V vs NHE were unable to oxidize Mesna. The results thus reflect on the
pro- and anti-oxidant properties of Mesna. 相似文献
3.
Atanu Barik K. Indira Priyadarsini Hari Mohan 《Research on Chemical Intermediates》2006,32(9):837-845
Reactions of peroxyl radicals and peroxynitrite with o-vanillin (2-hydroxy 3-methoxy benzaldehyde), a positional isomer of
the well-known dietary compound vanillin, were studied to understand the mechanisms of its free radical scavenging action.
Trichloromethylperoxyl radicals (CCl3O
2
·
) were used as model peroxyl radicals and their reactions with o-vanillin were studied using nanosecond pulse radiolysis technique
with absorption detection. The reaction produced a transient with a bimolecular rate constant of approx. 105 M−1s−1, having absorption in the 400–500 nm region with a maximum at 450 nm. This spectrum looked significantly different from that
of phenoxyl radicals of o-vanillin produced by the one-electron oxidation by azide radicals. The spectra and decay kinetics
suggest that peroxyl radical reacts with o-vanillin mainly by forming a radical adduct. Peroxynitrite reactions with o-vanillin
at pH 6.8 were studied using a stopped-flow spectrophotometer. o-Vanillin reacts with peroxynitrite with a bimolecular rate
constant of 3 × 103 M−1s−1. The reaction produced an intermediate having absorption in the wavelength region of 300–500 nm with a absorption maximum
at 420 nm, that subsequently decayed in 20 s with a first-order decay constant of 0.09 s−1. The studies indicate that o-vanillin is a very efficient scavenger of peroxynitrite, but not a very good scavenger of peroxyl
radical. The reactions take place through the aldehyde and the phenolic OH group and are significantly different from other
phenolic compounds. 相似文献
4.
Hari Mohan 《Journal of Chemical Sciences》2002,114(6):749-758
In neutral aqueous solution of (phenylthio)acetic acid, hydroxyl radical is observed to react with a bimolecular rate constant
of 7.2 × 10-1 dm3 mol−s− and the transient absorption bands are assigned to•OH radical addition to benzene and sulphur with a rough estimated values of 50 and 40% respectively. The reaction of the•OH radical with diphenyl sulphide (k = 4.3 × 108 dm3 mol−1 s−1) is observed to take place with formation of solute radical cation, OH-adduct at sulphur and benzene with estimated values
of about 12, 28 and 60% respectively. The transient absorption bands observed on reaction of•OH radical, in neutral aqueous solution of 4-(methylthio)phenyl acetic acid, are assigned to solute radical cation (λmax = 550 and 730 nm), OH-adduct at sulphur (λmax = 360 nm) and addition at benzene ring (λmax = 320 nm). The fraction of•OH radical reacting to form solute radical cation is observed to depend on the electron-withdrawing power of substituted group.
In acidic solutions, depending on the concentration of acid and electron-withdrawing power, solute radical cation is the only
transient species formed on reaction of•OH radical with the sulphides studied. 相似文献
5.
The transient absorption bands (λmax = 330, 525 nm, kf = 5 × 109 dm3 mol−1 s−1) obtained on pulse radiolysis of N2O‐saturated neutral aqueous solution of 4,4′‐thiodiphenol (TDPH) are due to the reaction of TDPH with ·OH radicals and are assigned to phenoxyl radical formed on fast deprotonation of the solute radical cation. The reaction of specific one‐electron oxidants (Cl2·−, Br2·−, N3·, TI2+, CCl3OO·) with TDPH also produced similar transient absorption bands. The phenoxyl radicals are also produced on pulse radiolysis of N2‐saturated solution of TDPH in 1,2‐dichloroethane. The nature of transient absorption spectrum obtained on reaction of ·OH radicals with TDPH is not affected in acidic solutions, showing that OH‐adduct is not formed in neutral solutions. The oxidation potential for the formation of phenoxyl radical is determined to be 0.98 V. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 603–610, 1999 相似文献
6.
Reactions of e−aq, OH radicals and H atoms were studied with n-allylthiourea (NATU) using pulse radiolysis. Hydrated electrons reacted with
NATU (k = 2.8×109 dm3 mol−1 s−1) giving a transient species which did not have any significant absorption above 300 nm. It was found to transfer electrons
to methyl viologen. At pH 6.8, the reduction potential of NATU has been determined to be −0.527 V versus NHE. At pH 6.8, OH radicals were found to react with NATU, giving a transient species having absorption maxima at 400–410
nm and continuously increasing absorption below 290 nm. Absorption at 400–410 nm was found to increase with parent concentration,
from which the equilibrium constant for dimer radical cation formation has been estimated to be 4.9×103 dm3 mol−1. H atoms were found to react with NATU with a rate constant of 5 × 109 dm3 mol−1 s−1, giving a transient species having an absorption maximum at 310 nm, which has been assigned to H-atom addition to the double
bond in the allyl group. Acetoneketyl radicals reacted with NATU at acidic pH values and the species formed underwent reaction
with parent NATU molecule. Reaction of Cl.−2 radicals (k = 4.6 × 109 dm3 mol−1 s−1) at pH 1 was found to give a transient species with λmax at 400 nm. At the same pH, reaction of OH radicals also gave transient species, having a similar spectrum, but the yield
was lower. This showed that OH radicals react with NATU by two mechanisms, viz., one-electron oxidation, as well as addition to the allylic double bond. From the absorbance values at 410 nm, it has been
estimated that around 38% of the OH radicals abstract H atoms and the remaining 62% of the OH radicals add to the allylic
double bond. 相似文献
7.
Pulse radiolysis of resveratrol was carried out in aqueous solutions at pH ranging from 6.5 to 10.5. The one-electron oxidized
species formed by the N•3 radicals at pH 6.5 and 10.5 were essentially the same with λmax at 420 nm and rate constant varying marginally (k = (5−6.5) × 109 dm3 mol−1 s−1). The nature of the transients formed by NO•2, NO• radical reaction at pH 10.5 was the same as that with N•3, due to the similarity in decay rates and the absorption maximum. Reaction of •OH radical with resveratrol at pH 7 gives an absorption maximum at 380 nm, attributed to the formation of carbon centered
radical. The repair rates for the thymidine and guanosine radicals by resveratrol were approx. 1 × 109 dm3 mol−1 s−1, while the repair rate for tryptophan was lower by nearly an order of magnitude (k = 2 × 108 dm3 mol−1 s−1). The superoxide radical anion was scavenged by resveratrol, as well as by the Cu–resveratrol complex with k = 2 × 107 and 1.5 × 109 dm3 mol−1 s−1, respectively. Its reduction potential was also measured by cyclic voltammetry. 相似文献
8.
The reactions of e−
aq, H-atoms, OH radicals and some one electron oxidants and reductants were studied with dithio-oxamide (DTO) in aqueous solutions
using pulse radiolysis technique. The transient species formed by the reaction of e−
aq with DTO at pH 6.8 has an absorption band with λ
max at 380 nm and is reducing in nature. H-atom reaction with DTO at pH 6.8 also produced the same transient species. The semi-reduced
species was found to be neutral indicating that the electron adduct gets protonated quickly. However at pH 1, the species
produced by H-atom reaction had a different spectrum with λ
max at 360 and 520 nm. Reaction of acetone ketyl radicals and CO2
− radicals with DTO at pH 6.8 gave transient spectra which were identical to that obtained by e−
aq reaction. However at pH 1, the spectrum obtained by the reaction of acetone ketyl radicals with DTO was similar to that obtained
by H-atom reaction at that pH. The transient species formed by OH radical reaction with DTO in the pH range 1–9.2 also has
two absorption maxima at 360 and 520 nm. This spectrum was identical with the spectrum obtained by H-atom reaction at pH 1.
This means that all these radicals viz. OH, H-atom and (CH3)2COH radicals react with DTO at pH 1 by H-abstraction mechanism. The transient species produced was found to be sensitive to
the presence of oxygen. One-electron oxidizing radicals such as Br2
−· and SO4
−· radicals reacted with DTO at neutral pH to give the same species as produced by OH radical reaction having absorption maxima
at 360 to 520 nm. At acidic pHs, only Br2
−· and Cl2
−· radicals were able to oxidize DTO to give the same species as produced by OH radical reaction. The semioxidized species is
a resonance stabilized species with the electron delocalized over the-N-C-S bond. This species was found to be neutral and
non-oxidizing in nature. 相似文献
9.
Veleeparambil M. Manoj Usha K. Aravind Hari Mohan Charuvila T. Aravindakumar 《Research on Chemical Intermediates》2011,37(8):1113-1122
The decomposition studies of S-nitrosothiols (RSNO) are important due to their potential role in vivo in connection with the storage and transport of nitric
oxide (•NO) within the body. Reactions of hydroxyl radicals (•OH) with a number of RSNOs (S-nitroso derivatives of N-acetyl-dl-penicillamine, l-cysteinemethylester, N-acetylcysteamine, and dl-penicillamine) in aqueous medium at neutral and acidic pH have been reported in the present study. Radiation chemical technique
(steady state and pulse radiolysis) has been utilized for the determination of the reaction rate constants, the end product
analyses, and the transient intermediate species. The rate constants for the reaction of •OH with the selected RSNOs were determined using a competition kinetic method with 2′-deoxy-d-ribose as the competitor. All the rate constants were found to be of the order of diffusion controlled (1010 M−1 s−1). The degradation yield of RSNOs was found to be quantitative (i.e., G(–RSNO) ≈ G(•OH)) at neutral and acidic pH. The major products of decomposition were the respective disulfide (RSSR) and nitrite (NO2
−). A good material balance is also obtained between the degradation yield and the formation of the products (i.e., G(–RSNO) ≈ G(RSSR) + G(NO2
−)). The major transient intermediate was the thiyl radical (RS•). Its intermediacy was confirmed by making use of the electron transfer reaction of 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate)
(ABTS2−) to RS•, which results in the formation of ABTS•− having a transient absorption spectrum with λmax at 410 nm. Based on these results, a generalized reaction mechanism is deduced for the reaction of •OH with RSNO. 相似文献
10.
Using pulse radiolysis technique, the one-electron oxidation of vanillin (V-OH) with azide radicals, at pH 6 and 9 resulted in the formation of vanillin phenoxyl radical with k = 6.7 × 107 and 2.5 × 109 dm3 mol-1 s-1, respectively. The transient absorption spectra of the vanillin phenoxyl radical (V-O) formed either at pH 6 or 9, showed a
max at 410 nm. At pH 5, the OH radicals seem to form an adduct with vanillin,
max at 430 nm and k(OH + V-OH) = 3.3 × 109 dm3 mol-1 s-1, while at pH 9, the OH radical reaction resulted in the formation of vanillin phenoxyl radical with
max at 410 nm and k(OH + V-O-) = 6.6 × 109 dm3 mol-1 s-1. The reactivity of NO2radicals with vanillin is lower by orders of magnitude signifying an incomplete reaction. In general, the rate constants for the reaction of OH, N, NO radicals with vanillin were higher at pH 9 than at the lower pH. Its reactivity with other one-electron oxidants like CCl3OO, CHCl2OO and CH radicals and the ability to chemically repair tryptophanyl and guanosyl radicals with k = 1.5 - 4 × 107 dm3 mol-1 s-1 indicate its antioxidative behaviour. 相似文献
11.
Radiation chemical reactions of•OH, O•−, N3
•and e
aq
t-
witho- and m-hydroxycinnamic acids were studied. The second-orderrateconstantsforthereaction of•OH with ortho and meta isomers in buffer solution at pH7 are 3.9±0.2 × 109 and 4.4 ± 0.3 × 109 dm3 mol-1 s-1 respectively. At pH 3 the rate with the ortho isomer was halved (1.6 ± 0.4 × 109 dm3 mol-1 s-1) but it was unaffected in the case of meta isomer (k = 4.2±0.6 × 109dm3mol-1 s-1). The rate constant in the reaction of N3
• with the ortho isomer is lower by an order of magnitude (k = 4.9 ± 0.4 × 108 dm3 mol-1s-1). The rates of the reaction of e
aq
t-
with ortho and meta isomers were found to be diffusion controlled. The transient absorption spectrum measured in the•OH witho-hydroxycinnamic acid exhibited an absorption maximum at 360 nm and in meta isomer the spectrum was blue-shifted (330 nm)
with a shoulder at 390 nm. A peak at 420 nm was observed in the reaction of Obb−with theo-isomer whereas the meta isomer has a maximum at 390 and a broad shoulder at 450 nm. In the reaction of the absorption peaks
were centred at 370–380 nm in both the isomers. The underlying reaction mechanism is discussed. 相似文献
12.
Konrad Skotnicki Ireneusz Janik Klaudia Sadowska Grazyna Leszczynska Krzysztof Bobrowski 《Molecules (Basel, Switzerland)》2022,27(1)
One-electron oxidation of 2-selenouracil (2-SeU) by hydroxyl (●OH) and azide (●N3) radicals leads to various primary reactive intermediates. Their optical absorption spectra and kinetic characteristics were studied by pulse radiolysis with UV-vis spectrophotometric and conductivity detection and by the density functional theory (DFT) method. The transient absorption spectra recorded in the reactions of ●OH with 2-SeU are dominated by an absorption band with an λmax = 440 nm, the intensity of which depends on the concentration of 2-SeU and pH. Based on the combination of conductometric and DFT studies, the transient absorption band observed both at low and high concentrations of 2-SeU was assigned to the dimeric 2c-3e Se-Se-bonded radical in neutral form (2●). The dimeric radical (2●) is formed in the reaction of a selenyl-type radical (6●) with 2-SeU, and both radicals are in equilibrium with Keq = 1.3 × 104 M−1 at pH 4 (below the pKa of 2-SeU). Similar equilibrium with Keq = 4.4 × 103 M−1 was determined for pH 10 (above the pKa of 2-SeU), which admittedly involves the same radical (6●) but with a dimeric 2c-3e Se-Se bonded radical in anionic form (2●−). In turn, at the lowest concentration of 2-SeU (0.05 mM) and pH 10, the transient absorption spectrum is dominated by an absorption band with an λmax = 390 nm, which was assigned to the ●OH adduct to the double bond at C5 carbon atom (3●) based on DFT calculations. Similar spectral and kinetic features were also observed during the ●N3-induced oxidation of 2-SeU. In principle, our results mostly revealed similarities in one-electron oxidation pathways of 2-SeU and 2-thiouracil (2-TU). The major difference concerns the stability of dimeric radicals with a 2c-3e chalcogen-chalcogen bond in favor of 2-SeU. 相似文献
13.
《Radiation Physics and Chemistry》2006,75(1):70-77
Pulse radiolysis technique has been employed to study the reaction of different oxidizing and reducing radicals with mangiferin. The reaction of OH radical showed the formation of transient species absorbing in 380–390 and 470–480 nm region. The reaction with specific one-electron oxidants (N3, CCl3O2) also showed the formation of similar transient absorption bands and is assigned to phenoxyl radicals. The pKa values of the transient species have been determined to be 6.3 and 11.9. One-electron oxidation potential of mangiferin at pH 9 has been found to be 0.62 V vs. NHE. The reaction of eaq− showed the formation of transient species with λmax at 340 nm, which is assigned to the ketyl anion radical formed on addition of eaq− at carbonyl site. Reactions of one-electron oxidised mangiferin radicals with ascorbic acid have also been studied. 相似文献
14.
Puspalata Rajesh G. R. Dey D. B. Naik K. Kishore 《Research on Chemical Intermediates》2008,34(1):53-65
Reactions of 2- and 3-nitro anilines (2- and 3-NA) with eaq−, H-atoms and one-electron reductants have been studied using pulse radiolysis in aqueous solutions. Reactions of eaq− were found to be quite fast with both 2-NA and 3-NA resulting in their corresponding semi-reduced species which are reducing
in nature. Reduction potentials for 2-NA/2-Na•′ have been estimated to be approx. −0.56 Vvs. NHE and that for 3-NA/3-NA•− was found to be between −0.185 V and −0.45 Vvs. NHE. Semi-reduced 2-NA has main absorption peak at 300 nm with a shoulder in the 350 nm region and a broad weak band in
the 470–500 nm region, whereas semi-reduced 3-NA possesses an absorption peak at 520 nm. Reducing radicals such as (CH3)2 C•OH and CO2•− reacted with 2-NA, producing semi-reduced species, whereas reactions of these radicals with 3-NA produced their corresponding
radical-adduct species. 相似文献
15.
Nature of the transient species formed during pulse radiolysis of thioacetamide in aqueous solutions
K. Kishore P. Dwibedy G. R. Dey D. B. Naik P. N. Moorthy 《Research on Chemical Intermediates》1998,24(1):35-45
Thioacetamide (TA) is an organic compound having thioamide group similar to that in thiourea derivatives. Its reactions with
eaq−, H-atom and OH radicals were studied using the pulse radiolysis technique at various pHs and the kinetic and spectral characteristics
of the transient species were determined. The initial adduct formed by the reaction of TA with OH radicals at pH 7 does not
absorb light in the 300–600 nm region but reacts with the parent compound to give a transient species with an absorption maximum
around 400 nm. At pH 0, the reaction of OH radicals with TA directly gives a similar transient species with absorption maximum
at 400 nm. Transient species formed by H-atom reaction with TA and pH 0 has no absorption in the 300–600 nm region but at
higher acidity a new transient species is formed which has absorption maximum at 400 nm. This transient absorption observed
in the case of both OH and H atom reaction with TA is ascribed to the formation of a resonance stabilized radical similar
to that obtained in the case of thiourea derivatives. The species produced by electron reaction viz. electron adduct was found to be a strong reductant and could reduce MV2+ with a high rate constant. H2S was produced as a stable product in the reaction of eaq− and its G-value was determined to be about 0.8. 相似文献
16.
Specific features of the kinetics of alkane and alkylbenzene oxidation with HOONO formed in the H2O2-NaNO2 system (pH 4.27) are quantitatively explained assuming the simultaneous occurrence of reactions in the gas and liquid phases.
A model of the kinetic distribution method is developed and verified that accounts for the equilibrium distribution of a substrate
and a reagent between phases and their interaction in both phases. Relative rate constants for the oxidation ofn-alkanes (C3-C8), isobutane, cyclopentane, cyclohexane, benzene, and alkylbenzenes are measured over a wide range of the volume ratios of
the gas and liquid phases (λ = Vg/V1). Relative rate constants for the oxidation of alkanes in the gas phase and alkylbenzenes in gas and solution were determined.
Similarity in substrate selectivities and kinetic isotope effects of the gasphase reactions of alkanes and arenes with peroxynitrous
acid and•OH radicals suggest that hydroxyl radical or the ˙OH...NO2 radical pair is an active species in the gas phase. In solution, alkylbenzenes react nonselectively with HOONO, as well as
with ˙OH radicals. In contrast to the liquid-phase oxidation of arenes, the liquidphase oxidation of all alkanes under study
insignificantly contribute (5–15%) to the overall rate of the substrate consumption. 相似文献
17.
The photooxidation of adenosine in presence of peroxydisulphate (PDS) has been studied by spectrophotometrically measuring
the absorbance of adenosine at 260 nm. The rates of oxidation of adenosine by sulphate radical anion have been determined
in the presence of different concentrations of caffeic acid. Increase in [caffeic acid] is found to decrease the rate of oxidation
of adenosine suggesting that caffeic acid acts as an efficient scavenger of SO
4
•
and protects adenosine from it. Sulphate radical anion competes for adenosine as well as for caffeic acid. The quantum yields
of photooxidation of adenosine have been calculated from the rates of oxidation of adenosine and the light intensity absorbed
by PDS at 254 nm, the wavelength at which PDS is activated to sulphate radical anion. From the results of experimentally determined
quantum yields (Φexpt1) and the quantum yields calculated (Φcal) assuming caffeic acid acting only as a scavenger of SO
4
•
show that Φexpt1 values are lower than Φexpt1 values. The ǵf values, which are experimentally found quantum yield values at each caffeic acid concentration and corrected
for
4
•
scavenging by caffeic acid, are also found to be greater than Φexpt1 values. These observations suggest that the transient adenosine radicals are repaired by caffeic acid in addition to scavenging
of sulphate radical anions. 相似文献
18.
K. Pietrucha L. Góra K. Burczak 《Journal of Radioanalytical and Nuclear Chemistry》1998,232(1-2):83-86
Hydroxyl radicals were generated radiolytically in N2O-saturated aqueous solutions of the aminoglycoside antibiotic, gentamycin. Using the pulse radiolysis technique, the rate
constant of OH radicals with gentamycin determined was 1.2·109 dm3·mol−1·s−1. Upon.OH attack a transient species with an absorption maximum at 270 nm is observed which decays by second-order kinetics within
the solute concentration range of 3.2·10−5 to 1·10−3mol·dm−3. Transient species undergoes transformation to a permanent product absorbing between 260 and 340 nm with maximum absorption
at 300 nm. Rate constant of the reaction of bimolecular decay of gentamycin radicals, k (Gen.+Gen.) was found to be ≈ 1.4·107 dm3·mol−1·s−1. 相似文献
19.
The pulse radiolysis of FA and FA:water solutions was studied in the absence and presence of redox indicator 1,1′-dimethyl-4,4′-bipyridinium
dichloride (methyl viologen, MV2+). The experiments performed in the presence of MV2+ have provided strong support to the idea that the first species obtained from the reaction of esol− and •OH with FA produces radicals that show reactivity towards the MV2+. Both the radicals on reaction with MV2+ results in the appearance of the well-known intense blue MV•+ radical absorption signal (λmax = 395 nm, λmax = 605 nm). The intermediate radicals formed during radiolysis were used to generate silver nanoparticles. 相似文献
20.
Alexander Konkin Frank Wendler Frank Meister Hans-Klaus Roth Albert Aganov Oliver Ambacher 《Cellulose (London, England)》2007,14(5):457-468
Degradation processes of N-methylmorpholine-N-oxide monohydrate (NMMO), cellulose and cellulose/NMMO solutions were studied by high performance liquid chromatography (HPLC)
and electron spin resonance (ESR) spectroscopy. Kinetics of radical accumulation processes under UV (λ = 248 nm) excimer laser
flash photolysis was investigated by ESR at 77 K. Beside radical products of cellulose generated and stabilized at low temperature,
radicals in NMMO and cellulose/NMMO solutions were studied for the first time in those systems and attributed to nitroxide
type radicals ∼CH2–NO•–CH2∼ and/or ∼CH2–NO•–CH3∼ at the first and methyl •CH3 and formyl •CHO radicals at the second step of the photo-induced reaction. Kinetic study of radicals revealed that formation and recombination
rates of radical reaction depend on cellulose concentration in cellulose/NMMO solutions and additional ingredients, e.g.,
Fe(II) and propyl gallate. HPLC measurements showed that the concentrations of ring degradation products, e.g., aminoethanol
and acetaldehyde, are determined by the composition of the cellulose/NMMO solution. Results based on HPLC are mainly maintained
by ESR that supports the assumption concerning a radical initiated ring-opening of NMMO. 相似文献