FTIR analyses

Properties Rice husk Wheat gluten husk 

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Figure 8. Example of FTIR analysis of Polysulfone (PS) ultrafilter static adsorption test.

The formation of these polar groups contributes increased adhesion. Observation of disappearing vinyl groups in the silane coupling agent and of the formation of polystyrene in the silica by FTIR analysis (Fig. 15) have confirmed the occurrence of a reaction between the polymer and the silane coupling agent [77]. 

An amine-terminated poly ether (ATPE) is prepared as follows. Charge poly(tetramethylene oxide) diol (PolyTHF 1000, BASF, 75.96 g, 0.0759 m) to a 500-mL three-neck round-bottom flask fitted with a thermocouple, a mechanical stirrer, and a vacuum port. Add tert-butylacetoacetate (24.04 g, 0.1582 m) and apply vacuum. Heat at 175° C for 4 h, Fourier transform infrared (FTIR) analysis should indicate complete loss of the polyol OH absorption at 3300 cm. The room temperature viscosity of the product should be about 520 mPa-s. React this acetoacetylated product (85.5 g, 0.0649 m) with cyclohexylamine (14.5 g, 0.1465 m) at 110° C under vacuum for several hours. Cool the resultant cyclohexylaminocrotonate poly ether product to room temperature (1790 mPa-s at room temperature). 

The stress curve sharply increases when the steric component appears upon compression. The initial thickness of a deformed layer is equal to be half the distance Dq obtained by extrapolating the sharpest initial increase to stress zero. The value Do is 21 1 nm, which is close the thickness of two molecular layers (19.2 nm) of the a-helix brush, calculated using the CPK model and the orientation angles obtained by FTIR analysis. We have calculated the elastic compressibility modulus Y,... 

Since spillover phenomena have been most directly sensed through the use of IR in OH-OD exchange [10] (in addition, in the case of reactions of solids, to phase modification), we used this technique to correlate with the catalytic results. One of the expected results of the action of Hjp is the enhancement of the number of Bronsted sites. FTIR analysis of adsorbed pyridine was then used to determine the relative amounts of the various kinds of acidic sites present. Isotopic exchange (OH-OD) experiments, followed by FTIR measurements, were used to obtain direct evidence of the spillover phenomena. This technique has already been successfully used for this purpose in other systems like Pt mixed or supported on silica, alumina or zeolites [10]. Conner et al. [11] and Roland et al. [12], employed FTIR to follow the deuterium spillover in systems where the source and the acceptor of Hjp were physically distinct phases, separated by a distance of several millimeters. In both cases, a gradient of deuterium concentration as a function of the distance to the source was observed and the zone where deuterium was detected extended with time. If spillover phenomena had not been involved, a gradientless exchange should have been observed. 

Wieboldt et al. [560] have described SFE-SFC-FTIR analysis of hindered phenol primary antioxidants and phosphite secondary antioxidants in PE. SFE is more selective for the lower-range low-MW polymer than Soxhlet-type extraction. This yields a chromatogram with less interference from low-MW polymer peaks in the region where the additive components elute. As a result, SFE appears to be a better choice than Soxhlet-type extraction for the selective removal of additives from flaked polymer. SFE and dissolution/precipitation methods were compared for a PVC/stabiliser system [366]. 

Infrared measurement of additive concentrations is a more complex analysis than initially expected, as some additives may undergo a variety of chemical reactions during processing, as shown by Reeder et al. [128] for the FTIR analysis of phosphites in polyolefins. Some further examples of IR work refer to PVC/metal stearates [129], and PE/Santonox R [68,130]. Klingbeil [131] has examined the decomposition of various organic peroxyesters (TBPB, TBPP, TBPA and TBPO) and a peroxidicarbonate (BOPD) as a function of pressure, temperature and solvent by means of quantitative FTIR using an optical high p, T reaction cell. 

M. Reeder, W. Enlow and E. Borkowski, Factors Influencing the FTIR Analysis of Phosphites in Polyolefins, Technical Paper FI 81, GE Specialty Chemicals, General Electric Company, Parkersburg, WV (1989). 

Consequently, the major experimental options for the analyst are packed or capillary SFC, mobile phase with/without modifier and off-line or on-line mode, namely direct deposition (DD-SFC-FUR) vs. flowcell. Both small-bore packed columns and narrow-bore open-tubular columns have been used for SFC-FTIR analysis using a pressure-stable, thermostated, flow-cell or solvent elimination interfaces. 

Since the ketene will copolymerize with cyclopropanone, excess ketene was removed by addition of 3A molecular sieves followed by evacuation at 1 mm Hg for 2-3 hours at -70°C. The amount of ketene was monitored by FTIR analysis. Ketene has a distinct strong absorption between 2130 and 2150 cm-1 (5,6). The solution FTIR spectrum of cyclopropanone in Figure 1 was taken before ketene removal. 

Federica Prinetto and Giovanna Ghiotti from University of Torino are gratefully acknowledged for FTIR analysis. 

Fanson, P.T., Horton, M.R., Delgass, W.N. et al. (2003) FTIR Analysis of Storage Behavior and Sulfur Tolerance in Barium-Based NOx Storage and Reduction (NSR) Catalysts, Appl. Catal. B Environ., 46, 393. 

If additional information pertaining to the rubber composition were sought, FTIR analysis of the pyrolysis products would have been performed. Even more detailed analysis can be obtained by gas chromatography (GC) separation of the multiple pyrolysis products followed by mass spectrometric (MS) detection. The gas chromatography-mass spectrometry (GC-MS) method is well suited to deformulation and contaminant analysis. 

The FTIR spectrum for the dried paint resin does have a reasonable match score to and feature bands characteristic of an alkyd resin [5]. Due to the presence of fillers though, the spectral analysis did not allow for a high-quality match to be obtained. Removal of the fillers and subsequent FTIR analysis would provide the best spectroscopic result for the identification of the alkyd type and provide a better comparison to such as the reference vinyl toluene-modified alkyd. 

Si element ATR-FTIR spectroscopy was used to analyze this residue, and its spectrum, along with the closest library matches, are shown in Figure 41. The absorbance of this residue is low as a consequence of the thin layer present on the plate. This makes matching the sample spectrum with a reference spectrum somewhat difficult. The closest matches extracted from the library interrogated are to ester-based plasticizer materials, which is consistent with a phthalate-plasticized PVC. A more specific identification could have been made with further testing such as subjecting the residue to GC-MS analysis, but the information suggested by the ATR-FTIR analysis was, in this case sufficient. 

To ensure complete conversion for all examples of a 21-member library, irradiation times of 30-60 min were used (Scheme 7.39), employing a multi-vessel rotor system for parallel microwave-assisted synthesis (see Fig. 3.7). The results were confirmed by on-bead FTIR analysis, accurate weight-gain measurements of washed and dried resins, and post-cleavage analysis of the prepared enones. 

The isocyanates were added to the respective resin-bound amines suspended in dichloromethane in open glass tubes. The resulting reaction mixtures were each irradiated in a single-mode microwave cavity for 2 min intervals (no temperature measurement given) (Scheme 7.52). After each step, samples were collected for on-bead FTIR analysis. Within 12 min (six irradiation cycles), each reaction had reached completion. Acid cleavage of the polymer-bound ureas furnished the corresponding hydrouracils. 

Fourier spectroscopy, 23 137 Fourier transformation, essential equations for, 14 226-227 Fourier transform (FT) infrared (ftir) analysis, 19 563-564, 813. See also Microscopy-ftir technique dichroism, in silicone network characterization, 22 569 instruments, 23 138 advantages of, 14 228 resolution for, 14 227 microscopy, 14 232... 

It is also possible to carry out a GC-GC-FTIR analysis (see Triple Hyphenated Methods ). FTIR is very rapid, which means that several scans of the eluting material can usually be obtained. These are automatically combined by the spectrometer to give the final spectrum. The more scans that can be obtained, the more noise can be reduced, producing a cleaner spectrum. 

Explain why the eluents used in HPLC might interfere with FTIR analysis. 

Abstract In the beginning, the mixed potential model, which is generally used to explain the adsorption of collectors on the sulphide minerals, is illustrated. And the collector flotation of several kinds of minerals such as copper sulphide minerals, lead sulphide minerals, zinc sulphide minerals and iron sulphide minerals is discussed in the aspect of pulp potential and the nature of hydrophobic entity is concluded from the dependence of flotation on pulp potential. In the following section, the electrochemical phase diagrams for butyl xanthate/water system and chalcocite/oxygen/xanthate system are all demonstrated from which some useful information about the hydrophobic species are obtained. And some instrumental methods including UV analysis, FTIR analysis and XPS analysis can also be used to investigated sulphide mineral-thio-collector sytem. And some examples about that are listed in the last part of this chapter. 

FTIR Analysis of Adsorption of Thio-Collectors on Sulphide Minerals... 

Because of the strong hydrolysis property of antimony salt, it is very difficult to prepare antimony xanthate salt to obtain its IR spectrums. Therefore, the formation of antimony xanthate is difficult to be identified by the UV and FTIR analysis, which has been determined by using XPS. Finally, it can be concluded that the interaction mechanism between ethyl xanthate and jamesonite are attributed to the formation of lead and antimony xanthate on the surface in the light of flotation results, voltammogram measurement, UV and FTIR as well as XPS analyses. 

Cases, J. M. and de Donato, P., 1991. FTIR analysis of sulphide mineral surfaces before and after collection galena, in K. S. E. Forssberg(ed.), Flotation of Sulphide Minerals. Inter. J. Mineral Process, 33 49 - 65... 

In a dehydration reaction (Scheme 12.4), the IR band of the formamide carbonyl group at 1684 cm in (7) decreased and eventually converted to the isonitrile band at 2150 cm in (8) (Fig. 12.8). In a separate example (Scheme 12.5), the conversion of the IR band from the carbonate carbonyl group in (9) to the IR band of the carbamide carbonyl group in (10) can be monitored to assure the reaction completion (Fig. 12.9). Based on FTIR analysis, the reaction time course can be analyzed by integrating peak areas of the IR bands from the starting resin and the product. From the point of view of kinetics, the side reaction product formation can be excluded if the pseudo first order rates of the starting material consumption and the product formation are identical. 

The rate of a chemical reaction depends on temperature. A rule of thumb for many organic reactions in solution is that a 10 °C change in temperature causes a two- to three-fold change in rate of reaction [25]. To study the temperature dependence of solid-phase reactions, the cleavage reaction of resin (35) with n-butyla-mine at 20, 40 and 60 °C were carried out. The cleavage time courses and pseudo-first-order rate fits at these three temperatures are shown in Fig. 12.20. The rate constants from single bead FTIR analysis are Hsted in Tab. 12.4. Compared with the reaction at 20 °C, the solid-phase cleavage reaction of resin 3b was two times faster at 40 °C and four times faster at 60 °C. 

Fig. 7. The crystal structure of the C-domain of hemopexin (PDB accession number IHXN) 128) showed a four-bladed p-propeller structure, which because of sequence similarity was also expected in the N-domain. The high degree of beta structure and limited a-helix content agrees with the earlier FTIR analysis.

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