Dilute-Solution Behavior of Cellulose Tris(3,5-dimethylphenylcarbamate)

Tsuboi, Akihiko; Yamasaki, Mikiya; Norisuye, Takashi; Teŕamoto, Akio

doi:10.1295/polymj.27.1219

Cited by 17 publications

(25 citation statements)

References 39 publications

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“…Analogous cellulose derivatives, cellulose tribenzoate and cellulose tris(4-chlorophenylcarbamate), have been reported to have the same left-handed 3/2 helical structure by means of X-ray analysis. Moreover, it was reported from light scattering and viscometry measurements that CTPC may hold a similar helical structure even in solution. , On the basis of these reported structure data, we are able to build up a model polymer as described later.…”

Section: Resultsmentioning

confidence: 86%

NMR Studies of Chiral Discrimination Relevant to the Liquid Chromatographic Enantioseparation by a Cellulose Phenylcarbamate Derivative

1996

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Chromatographic enantioseparation of 1,1‘-bi-2-naphthol (2) and its mono- and di-O-methylated derivatives (3a, 3b), 2,2‘-dihydroxy-6,6‘-dimethylbiphenyl (4), and 10,10‘-dihydroxy-9,9‘-biphenanthryl (5) has been performed on cellulose tris(5-fluoro-2-methylphenylcarbamate) (1) as a chiral stationary phase for high-performance liquid chromatography (HPLC). The complete base-line separation of 2 and 4 was achieved with the elution order of enantiomers such that the (R)-isomers eluted first followed by the (S)-isomers. The resolution of 5 and the O-methylated 3 was difficult on 1. The cellulose derivative 1 dissolved in chloroform also exhibited a chiral discrimination for 2 and 4 in 1H and 13C NMR spectroscopies as well as in HPLC. The hydroxy and some aromatic protons and carbon resonances of 2 and 4 were clearly separated into a pair of peaks due to enantiomers in the presence of 1. The binding geometry and dynamics between 1 and the enantiomers of 2 were investigated on the basis of spin−lattice relaxation time, 1H NMR titrations, and intermolecular NOEs in the presence of 1. These NMR data are fully consistent with the chromatographic elution order. These results, combined with molecular modeling, reveal the chiral discrimination rationale.

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Section: Resultsmentioning

confidence: 86%

NMR Studies of Chiral Discrimination Relevant to the Liquid Chromatographic Enantioseparation by a Cellulose Phenylcarbamate Derivative

1996

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“…Samples. Fully substituted samples of CTDC were previously 15 prepared by the reaction of cellulose with 3,5-dimethylphenyl isocyanate in pyridine at 140-150 °C followed by repeated fractional precipitation with NMP as the solvent and methanol as the precipitant. From these, 19 middle fractions were chosen for the present study.…”

Section: Methodsmentioning

confidence: 99%

“…The measurement was also made for the depolarized component, with an analyzer set in the horizontal direction, since the CTDC chain was optically anisotropic. For its specific refractive index increment at 25 °C, the previously determined values 15 of 0.105 cm 3 g -1 for 436 nm and 0.0966 cm 3 g -1 for 546 nm were used. Test solutions and NMP were made optically clean by filtration through a Millipore filter followed by centrifugation at about (4 × 10 4 )g for 2 h (Sorval RC-5C).…”

Section: Methodsmentioning

confidence: 99%

“…In our recent characterization work 15 by light scattering and viscometry, it was found that cellulose tris-[(3,5-dimethylphenyl)carbamate] (CTDC), whose chemical structure is shown in Figure 1, behaves like an unperturbed KP chain in 1-methyl-2-pyrrolidone (or N-methyl-2-pyrrolidone, NMP) at 25 °C but tends to undergo intramolecular excluded-volume effects when the weight-average molecular weight M w exceeds 10 6 . The persistence length estimated was 7.8 nm, indicating a considerable stiffness of the CTDC chain.…”

Section: Introductionmentioning

confidence: 99%

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Chain Stiffness and Excluded-Volume Effects in Dilute Polymer Solutions: Cellulose Tris[(3,5-Dimethylphenyl)carbamate]

1996

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Nineteen fractions of cellulose tris[(3,5-dimethylphenyl)carbamate] (CTDC) ranging in weight-average molecular weight M w from 2.5 × 104 to 7.5 × 106 have been studied by static light scattering, sedimentation equilibrium, and viscometry in 1-methyl-2-pyrrolidone at 25 °C. Since this cellulose derivative exhibits pronounced optical anisotropy, light-scattering data are corrected for the anisotropy effect on the basis of Nagai theory for the Kratky−Porod (KP) wormlike chain with cylindrically symmetric polarizabilities. It is shown that the data for 〈S 2〉z (the z-average mean-square radius of gyration), δ (the optical anisotropy factor), and [η] (the intrinsic viscosity) and those reported previously for 11 fractions are described accurately by the known theories for the unperturbed KP chain if M w is lower than 7 × 105. From the comparison, the persistence length and the monomeric projection of the CTDC chain are estimated to be 7.8 and 0.52 nm, respectively. When M w exceeds 106, i.e., when n K (the Kuhn segment number) increases above 50, excluded-volume effects on 〈S 2〉z and [η] become experimentally observable. Though such a large n K value for the appearance of volume effects has been considered inconsistent with the Yamakawa−Stockmayer−Shimada (YSS) theory for KP or helical wormlike chains, the observed excluded-volume effects are found to be explained quantitatively in the YSS scheme, i.e., by the YSS perturbation theory combined with the Domb−Barrett function for the radius expansion factor and the Barrett function for the viscosity expansion factor. Thus, this theoretical scheme should have a wider applicability than what might be anticipated from earlier studies.

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“…Very recently, we have investigated dilute-solution behavior and liquid crystal formation of this cellulose derivative in 1methyl-2-pyrrolidone (or N-methyl-2-pyrrolidone, NMP) by light scattering, sedimentation equilibrium, viscometry, and polarized microscopy (Refs. [5][6][7][8], and analyzed the experimental results on the basis of the Kratky-Porod wormlike chain (Ref. 9) with or without excluded volume.…”

Section: Introductionmentioning

confidence: 99%

Solution properties of cellulose tris(3,5‐dimethyl‐phenylcarbamate)

Norisuye

Tsuboi

Sato

et al. 1997

Macromolecular Symposia

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The dilute-solution behavior and liquid crystal formation of cellulose tris(3,5-dimethylphenylcarbamate) (CTDC) in 1-methyl-2-pyrrolidone (NMP) at 25OC are discussed by summarizing our recent studies, and its molecular characteristics are compared with those of cellulose tris(pheny1carbamate) (CTC) in the same solvent. The molecular weight dependences of optical anisotropy factor, radius of gyration, intrinsic viscosity ([q]), and isotropic-cholesteric phase boundary concentration for CTDC are explained consistently by current theories based on the wormlike chain. An analysis of the newly measured [q] for CTC shows that the backbone conformation and chain stiffness are substantially the same for the two cellulose derivatives in NMP. However, a distinct difference in optical anisotropy is found and briefly discussed in relation to the higher optical resolution capacity of CTDC than that of CTC in chromatographic separation of racemic compounds.

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Dilute-Solution Behavior of Cellulose Tris(3,5-dimethylphenylcarbamate)

Cited by 17 publications

References 39 publications

NMR Studies of Chiral Discrimination Relevant to the Liquid Chromatographic Enantioseparation by a Cellulose Phenylcarbamate Derivative

NMR Studies of Chiral Discrimination Relevant to the Liquid Chromatographic Enantioseparation by a Cellulose Phenylcarbamate Derivative

Chain Stiffness and Excluded-Volume Effects in Dilute Polymer Solutions: Cellulose Tris[(3,5-Dimethylphenyl)carbamate]

Solution properties of cellulose tris(3,5‐dimethyl‐phenylcarbamate)

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