FT-Raman spectra

Figure 3 FT-Raman spectra of TEAOH 40% (a) and of the TEAOH, TP A, TEA, and MCHA templates occluded in the as-synthesized AlP04-5 (b).

Computational methods were employed to predict molecular vibrations in 3-mercato-l,2,4-triazole 18 and 3,5-diamino-1,2,4-triazole 19 in order to fully assign the Fourier transform infrared (FTIR) and FT-Raman spectra of these molecules <2004SAA709, 2005SAA261>. 

The FT-Raman spectra of a range of drugs (theophylline, indomethacin, diclofenac, and promethazine) in several polymers (sodium alginate, hydroxy-propylmethylcellulose, and polyethylene glycol) have been obtained [56,57]. In these studies, the linearity of response of Raman scattering to species concentration was exploited to analyze diclofenac at concentrations of 0.01-6.0% w/w... 

Fig. 8 The FT-Raman spectra of polymorph I (upper) and polymorph III (lower) of carbamazepine. 

Fig. 9 The FT-Raman spectra of a paracetamol-dicalcium phosphate dihydrate mixture A, spectrum of pure paracetamol B, spectrum of pure dicalcium phosphate dihydrate C, spectrum of a mixture of paracetamol (5% w/w) in dicalcium phosphate dihydrate D, spectrum C minus spectrum B to identify pure paracetamol (compare with A). 

Fig. 10 The FT-Raman spectra over the wavenumber range 10-250cm-1 ofmagnesium stearate after different drying procedures. Top, heated at 90°C to constant weight under vacuum middle, heated to 60°C to constant weight under vacuum bottom, commercially supplied sample.

Figure 6 reproduces the Raman spectra in the region 800-1200 cm-1 reported by these authors for pure silicalite (sample 1) and for two TS-1 samples, 3 and 5, which contain 1.4 and 3.0 wt% Ti02. The spectra shown in Fig. 6a were recorded with a Fourier transfrom (FT) Raman spectrometer at an excitation wavelength of Aexc = 1064 nm (9398 cm-1), whereas those shown in Fig. 6b were excited with a UV-laser line at Aexc = 244 nm (40,984 cm-1). With each excitation wavelength, the pure silicalite gives rise to weak bands at 975 and 1085 cm -1 and a complex band centered near 800 cm-1. In the FT-Raman spectra of the dehydrated TS-1 samples (Fig. 6a), a band is clearly visible at 960 cm-1, the intensity of which increases with Ti02 content. 

R. Szostak and S. Mazurek, A quantitative analysis of liquid hydrocarbon mixtures on the basis of FT-Raman spectra registered under unstable conditions, J. Mol. Struct., 704, 235-245 (2004). 

In the case of the sulphur triimide S(NBu-f)3, the dispersive Raman technique applying a double monochromator and a CCD camera was employed to obtain the information from polarized measurements (solution studies) and also to obtain high-resolution spectra by low-temperature measurements. In the case of the main group metal complex, only FT-Raman studies with long-wavenumber excitation were successful, since visible-light excitation caused strong fluorescence. The FT-Raman spectra of the tetraimidosulphate residue were similar to those obtained from excitation with visible laser lines. 

FT-Raman spectra, collected in triplicate, was obtained using a Nicolet 870 spectrometer. 

Figure 12.12 Details of FT-Raman spectra of the [C4CiIm][PF5] and [C4QIm][BF4] ionic liquids at 25°C (Berg, R. W., Unpublished results, 2006. With permission.) Note that the characteristic bands of the AA and GA forms of the [C4CiIm]+ cation are present in both melts, as also found, for example, by Hamaguchi et al. [50].

Figure 12.24 Experimental FT-Raman spectra for the [CjC4pyr][Tf2N] liquid (in the figure [bmpy][Tf2N]) (Fujimori, T., Fujii, K., Kanzaki, R., Chiba, K., Yamamoto, H., Umebayashi, Y., and ishiguro, S.-i., /. Mol. Liquids 131-132, 216-224, 2007), showing that the spectum (top) at room temperature essentially consists of bands from both the [Tf2N] anion (middle) and the [CiC4pyr]+ cation (bottom) (shifted conveniently). The Fi+ and Cl do not contribute bands directly in the liquid but have influence on the structures of the salts and are interactive with the ions and influence the conformational equilibria in the IF (Berg, R. W., Unpublished results, 2006.)...

Macro-FT Raman Spectroscopy 4c The FT Raman spectra can be acquired in macromode on a small amount of beads. The advantages compared to single-bead Raman measurement are reduced acquisition time and the excitation energy. 

FT-Raman spectra are measured at room temperature on a FT-IR spectrometer (Bruker IFS66) equipped with an FT-Raman accessory (Bruker FRA 106) using a Nd-YAG laser (emission wavelength 1064 nm). The data are collected in the backscattering mode (180° excitation resolution 4 cm- 256 scans 19 mW). 

Fig. 9.7. (a) FT-Raman spectra top to bottom 5 mg active tablet, lmg active tablet, placebo, (b) ATR FT-IR spectra top to bottom placebo, lmg active tablet, 5 mg active tablet... 

Dyrby, M. Engelsen, S.B. Norgaard, L. etal., Chemometric quantitation of the active substance (containing C—N) in a pharmaceutical tablet using near-infrared (NIR) transmittance and NIR FT-Raman spectra Appl. Spectrosc. 2002, 56, 579-585. 

The FT-Raman spectra of the sulfur vulcanisates of the various model olefins do not contain the characteristic disulfide signal at 510 cm"1, but do contain the typical higher sulfide bands at 490, 460 and 440 cm"1 (Table 6.2). In addition, a new band at about 475 cm 1 is observed for the vulcanisates of 2-methyl-2-pentene and 3-hexene, which has not yet been assigned (hexasulfide ). Results of HPLC analysis have shown that the vulcanisate of 2,3-dimethyl-2-butene consists mainly of a mixture of disulfide to pentasulfide with about 15 mole% of disulfide [79]. This illustrates that FT-Raman spectroscopy is not very sensitive for the identification of disulfides. Because of an overlap of signals, FT-Raman does not provide detailed, quantitative information on the presence of the individual higher sulfides (S>2). 

It has been shown that during sulfur vulcanisation of EPDM the C=C peak of the residual ENB unsaturation at 1685 cm 1 seems to decrease in intensity in agreement with the observations by Fujimoto and co-workers [73,74] (see Section 6.2.2.1). However, in Section 6.2.2.2 it was shown that sulfur vulcanisation of the low-molecular-weight ENBH results in a shift of the Raman C=C peak from 1688 to 1678 cm 1. Taking this into account a closer inspection of the FT-Raman spectra reveals that the original C=C peak at 1690 cm"1 decreases in intensity, and a new peak is observed at 1681 cm"1. Actually, the C=C peak broadens towards lower wave numbers, but in a first approximation the total area remains constant. So, the sulfur substitution reaction of the allylic hydrogens is confirmed for the polymer system. This corresponds to the observation by Koenig and co-workers, namely that upon sulfur vulcanisation of cz s-BR, the C=C peak at 1650 cm 1 decreases in intensity and that of a new peak at 1633 cm-1 increases its intensity [19, 58]. 

Fig. 5. Laser Fourier transform (FT)-Raman spectra of the explosive formulation C-4, its main ingredient RDX, and samples of RDX of different origin. The exciting laser wavelength was 1064 nm [10].

Figures 4.24 and 4.25 show the FTIR spectra and FT Raman spectra of two samples, that is, a mesoporous molecular sieve (MMS) and a Ni-Y zeolite where aniline was incorporated and polymerized [67],...

FIGURE 4.25 FT Raman spectra of the adducts polyaniline-hosts in KBr pellets (a) MCM-41 MMS and (b) Ni-Y zeolite. 

Figure 3-32 Synchronous (A) and asynchronous (B) 2D FT-Raman spectra in the range 1620 1290 cm-1 constructed from the spectra of a set of blends containing PS and PPE polymers at the ratios of 100/0, 90/10 and 70/30. Black peaks indicate negative contours. (Reproduced with permission from Ref. 99.)...

This study illustrates a particular use of FT-Raman spectroscopy (Section 2.4.2) to monitor an emulsion polymerization of an acrylic/methacrylic copolymer. There are four reaction components to an emulsion polymerization water-immiscible monomer, water, initiator, and emulsifier. During the reaction process, the monomers become solubilized by the emulsifier. Polymerization reactions were carried using three monomers BA (butyl acrylate), MMA (methyl methacrylate), and AMA (allyl methacrylate). Figure 7-1 shows the FT-Raman spectra of the pure monomers, with the strong vC=C bands highlighted at 1,650 and 1,630 cm-1. The reaction was made at 74°C. As the polymerization proceeded, the disappearance of the C=C vibration could be followed, as illustrated in Fig. 7-2, which shows a plot of the concentration of the vC=C bonds in the emulsion with reaction time. After two hours of the monomer feed, 5% of the unreacted double bonds remained. As the... 

Figure 7-1 FT-Raman spectra of monomers (a) BA, (b) MMA, (c) AMA (inset shows C=C stretching region). (Reproduced from G. Ellis, M. Clayboume, and S. E. Richards, Spec. Acta. 46A, 227, Copyright 1990, with permission from Pergamon Press Ltd., Headington Hill Hall. Oxford 0X3 OBW, UK.)...

The study was conducted on a series of lipids such as oils, tallow and butter. Figures 7-4 and 7-5 illustrate Raman spectra of sunflower, corn, sesame, rapeseed and olive oils and peanut, beef tallow and butter, respectively. The study determined that the iodine number of the lipid containing foodstuffs could be estimated by measuring the FT-Raman spectra. The presence of double bonds in the unsaturated fatty acids in lipids provides a method of... 

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