Styrene spectrum

These couplings are exemplified below with reference to styrene (Spectrum 5.10). 

Similarily, Yoshida and Ranby (23) found a well-resolved 24-line spectrum for the growing vinyl acetate chain in dilute aqueous solution five nonresolved lines may be seen for the vinyl acetate popcorn system. Least structured is the styrene spectrum, with three nonresolved lines. In principle, the same features appear in the substituted styrenes represented in Figures 13 and 14, and the vinylpyridines (Figure 15). Only the form of the shoulders changes. With better resolution, these spectra should consist of at least six lines. 

Two-photon spectra of A <— X transitions in ben-zonitrile and styrene. Styrene spectrum also measured using MPI in a supersonic jet... 

Fig. 12. Friction-Speed Curves Calculated for SBR 913 Styrene) Spectrum for Storage Modulus...

Use SHMO to obtain the energy spectrum for the models methylenepentadiene. bicyclohexatriene, and styrene. IDraw all three energy level diagrams.. Are there degeneracies for these molecules ... 

Figure 7.5 Ultraviolet-visible spectrum of dehydrohalogenated copolymers of styrene-l-chloro-1,3-butadiene. [Redrawn with permission from A. Winston and P. Wichacheewa, Macromolecules 6 200 (1973), copyright 1973 by the American Chemical Society.]...

The observation of the spectrum for styrene polymerized on the surface of silane-treated silica and of the difference spectrum of polystyrene adsorbed on the surface of silica have revealed that there are absorption bands of atactic polystyrene at 1602, 1493, 1453, 756, and 698 cm. The absorption bands at 1411 and 1010 cm are related to vinyl trimethoxy silane, and C of the difference spectrum is below the base line. This indicates that the vinyl groups of silane react with styrene to form a copolymer. 

Loader 38) studied the Raman spectra of styrene adsorbed on different silicas—chromatographic grade silica gel, Cab-O-Sil, and Aerosil 380. The author utilized the fact that chemisorption will bring about marked changes in the spectrum whereas physical adsorption will cause only a broadening of the Raman lines accompanied in some cases by a frequency... 

Dynamic differential thermal analysis is used to measure the phase transitions of the polymer. IR is used to determine the degree of unsaturation in the polymer. Monitoring of the purity and raw is done commercially using gas phase chromatography for fractionization and R1 with UV absorption at 260 nanometers for polystyrene identification and measurement Polystyrene is one of the most widely used plastics because of fabrication ease and the wide spectrum of properties possible. Industries using styrene-based plastics are packaging, appliance, construction, automotive, radio and television, furniture, toy, houseware and baggage. Styrene is also used by the military as a binder in expls and rocket propints... 

Acrylic acid terpolymers have appeared on the market in recent years. With their broad spectrum of functions, they offer the potential for excellent waterside conditions. In particular, the terpolymers have proved to be very effective particulate iron oxides dispersants and colloidal iron stabilizers. Examples include acrylic acid/sulfonic acid/sodium styrene sulfonate (AA/SA/SSS), such as Good-Rite K781, K797, K798. A further example is acrylic acid/ sulfonic acid/substituted acrylamide (AA/SA/NI), such as Acumer 3100. 

Figure 2. FTIR spectrum of poly(t-butyl styrene)-b-poly(t-butyl methacrylate) (10% TBMA by weight).

Neutralization with KOH in aqueous THF gave the desired poly(styrene-b-potassium methacrylate) (S-b-MA.K). The carbonyl band in the IR spectrum is replaced with a strong, broad carboxylate absorption centered near 1566 cm 1 (Figure 2c). The carboxylate and potassium contents were assayed by non-aqueous titration and ICP, respectively. The resulting values of 0.91 meq COj /g and 0.98 meq K/g indicate essentially quantitative conversion to the potassium methacrylate. S-b-MA.K obtained in this manner is easily dissolved in solvents such as THF and dichloromethane, in contrast to the... 

Examination of the mass spectrum of P2VPY taken during the maximum decomposition rate reveals the major decomposition products as methylpyridine (93 a.m.u.), protonated vinyl pyridine (106 a.m.u.), and protonated dimer (211 a.m.u.) with ion ratios 74 100 59 respectively. Trimeric and tetrameric protonated species (316 and 421 a.m.u.) are also observed but in relatively small amounts. Protonated ions, rather than the simple monomers and dimers observed for the decomposition of poly(styrene) by MS11, may be created by a mechanism similar to that reported for the decomposition of 2-(4-heptyl)pyridine12 in the mass spectrometer. 

Copolymerization of isopropenylferrocene with styrene was accomplished in two ways. In one method (polymer 16 of Table III) styrene and isopropenylferrocene were mixed together in CH2CI2 at 20°C at a mole ratio of 23/77 of isopropenylferrocene to styrene, and polymerization was initiated with BF3 0Et2. From the 250-MHz NMR spectrum of the product, 27% styrene and 73% isopropenylferrocene units were found to be present in the copolymer, which had an Mu of 2900. This ratio was also confirmed by elemental analysis. 

In microphase-separated systems, ESR spectra may consist of a superposition of two contributions, from nitroxides in both fast and slow-tumbling regimes. Such spectra provide evidence for the presence of two types of domains with different dynamics and transition temperatures. This case was detected for a HAS-derived nitroxide radical in heterophasic polyfacrylonitrile-butadiene-styrene) (ABS) as shown in Figure 5, the fast and slow components in the ESR spectrum measured represent nitroxide radicals located in butadiene-rich (B-rich) and styrene/acrylonitrile-rich (SAN-rich) domains, respectively [40]. These two components were determined by deconvoluting the ESR spectrum of HAS-NO measured at 300 K. 

The spectrum of styrene in toluene was compared with that in toluene containing an equimolar quantity of Zr (benzyl) 4 at 0.06 M using a sweep of 2500 Hz. The methylene doublets of styrene were in identical positions (1115 and 1230 Hz) in these spectra. Experiment (b) (Table XIX) was repeated at — 60°C using 250-Hz expansion on a 100-MHz spectrometer. The benzyl resonance was observed to shift approximately 4 Hz (relative to toluene) upheld. The lack of splitting in the latter indicates equilibrium (if any occurs) is very rapid. Finally, the effect of temperature on the systems Zr (benzyl) 4 in styrene and Zr (benzyl) 4 toluene were examined and the results are given in Table XX. They show that no specific interaction of styrene with Zr (benzyl) 4 occurs. The interaction of toluene would probably be of the type (XXIV) whereas styrene would interact similarly or in a manner shown in (XXV), both interactions would affect the environment of the benzyl protons in Zr (benzyl) 4 if they occurred to any significant... 

The influence of adsorption on the structure of a -chymotrypsin is shown in Fig. 10, where the circular dichroism (CD) spectrum of the protein in solution is compared with that of the protein adsorbed on Teflon and silica. Because of absorbance in the far UV by the aromatic styrene, it is impossible to obtain reliable CD spectra of proteins adsorbed on PS and PS- (EO)8. The CD spectrum of a protein reflects its composition of secondary structural elements (a -helices, / -sheets). The spectrum of dissolved a-chymotrypsin is indicative of a low content of or-helices and a high content of //-sheets. After adsorption at the silica surface, the CD spectrum is shifted, but the shift is much more pronounced when the protein was adsorbed at the Teflon surface. The shifts are in opposite directions for the hydrophobic and hydrophilic surfaces, respectively. The spectrum of the protein on the hydrophilic surface of silica indicates a decrease in ordered secondary structure, i.e., the polypeptide chain in the protein has an increased random structure and, hence, a larger conformational entropy. Adsorption on the hydrophobic Teflon surface induces the formation of ordered structural elements, notably an increase in the content of O -helices (cfi, the discussion in Sect. 3.1.4). 

Figure 8. 31P-CP/MAS solid-state spectrum of polymer-bound (polystyrene cross-linked with 2% divinylbenzene) triphenylphosphine (a), 31P-CP/MAS solid-state spectrum of cis-[PtCl2(PPht-C6H -CH—CH2)2] (referenced to external 85% Hs POJ (b), 31P-CP/MAS solid-state spectrum of a copolymer of 65% styrene, 31% divinylbenzene and 4% cis-/PtCl2(PPh2-C6H -CH CH2)z] after soxhlet extraction (c) and 31P-CP/MAS solid-state spectrum of c s-[PtCl(PPhs)2, (N P )] ClOf after soxhlet extraction (d). All spectra referenced to external 85% HsPOk. (Reproduced from Ref. 21. Copyright by American Chemical Society.)...

As mentioned above, we planned to obtain optically pure styrenyl ethers through Zr-catalyzed kinetic resolution [5] subsequent metal-catalyzed rearrangement would afford optically pure chromenes. However, as shown in Scheme 11, the recovered starting material (40) was obtained with <10% ee (at 60% conversion) upon treatment with 10 mol% (,R)-(EBTHI)Zr-binol (3b) and five equivalents of EtMgCl (70°C, THF). We conjectured that, since the (EBT-HI)Zr-catalyzed reaction provides efficient resolution only when asymmetric alkylation occurs at the cyclic alkene site, competitive reaction at the styrenyl terminal olefin renders the resolution process ineffective. Analysis of the H NMR spectrum of the unpurified reaction mixture supported this contention. Indeed, as shown in Scheme 11, catalytic resolution of disubstituted styrene 49... 

The shift correlates in magnitude with the separation of each particular group distance-wise from the aromatic moiety of the substrate or product this points to the formation of an intermediate -complex, for which the rate of formation and the rate of decay can be determined. The 1H-PHIP-NMR spectrum, as well as the anticipated intermediate product-catalyst-re-complex observed during the hydrogenation of styrene, is outlined in Figure 12.19. 

Fig. 12.19 The H-PHIP-NMR spectrum and the anticipated intermediate product-catalyst-re-complex observed during the hydrogenation of styrene.

Fig. 12.22 CH2- and CH3-resonances observed in the -PHIP-NMR spectrum of the intermediate attached to an achiral catalyst during the hydrogenation of styrene.

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