Ethylbenzene spectra

You may have noticed that the two multiplets in the upheld part of the ethylbenzene spectrum are not quite symmetrical. In general, a multiplet leans upward toward the signal of the protons responsible for the splitting. In the ethyl signal (Figure 13-25) the quartet at lower field leans toward the triplet at a higher field, and vice versa. 

A chemist obtains the mass spectrum of l,2-dichloro-4-ethylbenzene. Give at least four possible fragments and the masses at which you would expect them to occur. Chlorine has two naturally occurring isotopes 35C1, 34.969 zu, 75.53%, and 37C1, 36.966 ti , 24.47%. The mass of H is 1.0078m,. See Major Technique 6, Mass Spectrometry, which follows this set of exercises. 

In the presence of an activator, naturally, the spectrum, yield, and lifetime are characteristics of the activator molecule. Indeed, the luminescence spectrum of the oxidized ethylbenzene was found to be identical to that of activator fluorescence [221]. 9,10-Dibromanthracene, 9,7-dipropylanthracene, and derivatives of oxazole were used as activators [221,223]. 

I ve included a spectrum of ethylbenzene (Fig. 135) to give you some idea of how to start interpreting NMRs. Obviously, you ll need more than this. See your instructor or any good organic chemistry text for more information. 

FIGURE 10.14 The NMR spectrum of ethylbenzene with integration trace. 

Figure 4 demonstrates the counter-diffusion of ethylbenzene vs. benzene. In this experiment, benzene was first taken up at 415 K from a stream of benzene in helium, with a benzene partial pressure of 1.15 mbar, until a steady state was reached (spectrum No. 0). Subsequently, ethylbenzene was admixed (1.15 mbar) with the benzene partial pressure and the total rate of the gas ilow remaining constant. Counter-diffusion is indicated by the decrease of the typical benzene absorbance at 1478 cm and the development of the typical ethylbenzene bands at 1605,1496 and 1453 cm (spectra Nos. 1-5). 

Friedel-Crafts catalysts (corrosion, continuous catalyst makeup). Although it gives a broader spectrum of alkylated products, recycling and transalkylation ensure high ethylbenzene yields. Steamed ZSM-5 and chrysozeolite ZSM-5 were shown by Union Carbide to afford ethylbenzene with high selectivity in the alkylation of benzene with ethanol.317... 

Figure 1.10 lal Absorption spectrum of ethylbenzene, showing the lowest energy vibrational band ibi absorption spectrum of acetylnaphthalene. showing an estimate of where the lowest energy vibrational band lies-... 

Figure 9.19—Proton decoupled 13C NMR spectrum of ethylbenzene. Each of the carbon atoms gives a signal consisting of a singlet. These large band decoupled spectra are simpler but contain less information.

Correlation in NMR is not a new concept to us. For instance, the H NMR spectrum of ethylbenzene (Figure 3.34) shows a clean triplet and quartet for the methyl and methylene groups, respectively. These two groups are correlated to each other because the... 

Figure 8. Comparison of ethylbenzene absorption spectrum in methanol (32 OMA accumulations) with published fluorescence spectrum in cyclohexane. Arrows indicate spectral region of difference.

Figure 10. Enlargement of spectral region where differences exist in the fluorescence spectrum of ethylbenzene (Figure 9) indicating the presence of naphthalene...

Proton NMR spectrum of ethylbenzene. The ethyl group appears as a triplet at 51.2 (-CH3) and a quartet at 52.6 (-CH2-). The aromatic protons appear as a multiplet near 57.2. 

A typical phosphorescence spectrum of atactic PS has been published by Vala, Haebig and Rice (19) together with the monomeric model ethylbenzene. The two spectra do not show substantial differences. PVCA is compared with N-isopropyl-carbazole and BCP in Figure... 

In Figure I we compare emission spectra for polystyrene in dilute solution and as a solid film, and for a model monomer, ethylbenzene, in dilute solution. Polystyrene in solution exhibits, in addition to a monomer-like emission, a broad excimer emission maximizing at emission spectrum is not unique to high molecular weight polymer. Indeed, 1,3-diphenylpropane exhibits (la,8) very similar total emission spectra. The excimer emission lifetime is (4) 12.5 ns in CH2CI2 at room temperature, while monomer-like emission decay and excimer emission rise times are reported (2) to be of the order of a nanosecond in cyclohexane solution. 

---