Pyrolysis, structural characterization

S. Tsuge and H. Othani, Structural characterization of polymeric materials by pyrolysis GC/MS, Polym. Degrad. Stab., 58, 109 130 (1997). 

Davies, N., Hill, W., and Kuckuk, R. (2002). Structural characterization of refractory organic substances by means of pyrolysis-GC/FTIR. In Refractory Organic Substances (ROS) in the Environment, Frimmel, F. H., Abbt-Braun, G, Heumann, K. G, Hock, B., Ltidemann, H.-D., and Spiteller, M., eds., Wiley-VCH, Weinheim, pp. 232-238. 

High-resolution NMR spectrometry was used first by Brown and Ladner for structural characterization of coal pyrolysis products (3). Other workers have extended this type of analysis to coal extracts (4) and coal hydrogenation products (5,6,7), A recently published com-... 

As noted above, the use of TMAH/thermochemolysis for the structural characterization of different humic materials have been applied in two different forms pyrolysis of the humic materials in the presence of TMAH or a confined reaction of the humic materials with the TMAH in a sealed glass ampoule at lower temperatures. Both methods release the same types of compunds. 

Pyrolysis in the presence of TMAH has also been applied to the structural characterization of HAs isolated from low-rank coals. Figure 6 shows the chromatogram of the compounds released after the TMAH/pyrolysis of the HA isolated from a humic coal from Konin (Poland). A large variety of components were released, the lignin-derived phenol derivatives and aliphatic acid methyl esters being the most prominent. A series of fatty acid methyl esters were identified in the range from Cio to C34, with maxima at C16 and Cig showing an even-over-odd... 

A new analytical procedure, termed TMAH thermochemolysis, has been used to assess the structure characterization of HS from a variety of samples. Although this procedure has mainly been performed in pyroprobe units at pyrolysis temperatures, it can also be conducted at subpyrolysis temperatures in sealed glass tubes. Therefore, this procedure can be easily implemented in any laboratory having gas chromatographic capabilities, in contrast to other chemolytic or pyrol c procedures. This is a potentially valuable advantage, because it makes the technique readily available to most geochemical laboratories. 

Spectroscopic and Structural Characterization 3.4.3.1 Pyrolysis-Mass Spectrometry... 

Fabbri D, Mongardi M, Mintanari L, Galletti GC, Chiavari G, Scotti R (1998b) Comparison between CP/MAS 13C-NMR and pyrolysis-GC/MS in the structural characterization of humins and humic acids of soil and sediments. 

Pyrolysis-GC/MS (Py-GC/MS) has increasingly been utilized in the field of structural characterization of versatile polymeric materials. This technique often provides a simple but rapid and extremely sensitive tool not only for ordinary solvent soluble polymers, but also for intractable cured polymers with three-dimensional networks. 

However, owing to recent developments in highly efficient separation columns for GC, and various powerful hyphenated identification techniques for GC such as GC/MS, GC/FTIR, and GC/atomic emission detector (AED), Py-GC has made great strides toward becoming a powerful tool for the structural characterization of polymeric materials. Therefore, Py-GC, in particular Py-GC/MS, now plays a very important role among various methods developed in the field of analytical pyrolysis. 

In this chapter, the history and scope of analytical pyrolysis are presented first, and then the instrumental and methodological aspects of Py-GC/MS are briefly discussed. Then, some recent typical applications of Py-GC/MS to the structural characterization of various pol5mieric materials will be discussed in detail. 

Abate, R., Ballistreri, A., Montaudo, G., Giuffrida, M., and Impallomeni, G., Separation and Structural Characterization of Cyclic and Open Chain Oligomers Produced in the Partial Pyrolysis of Microbial Poly(Hydroxbutyrates), Macromolecules, 28, 7911, 1995. 

Allegri G, Biasiolo M, Prison G, Pelli B, Traldi P (1987) Collisional Spectroscopy in Structural Characterization of Melanins. 1. A First Study on CgHvON" Ions Originating from Pyrolysis of Biosynthetic and Synthetic Tryptophan Melanins. Pigment Cell Res 1 87... 

IR and NMR spectroscopy are relatively easy-to-apply for a qnaUtative and comparative evaln-ation of the chemical structure and the DA determination. These techniques are nondestructive methods and do not need initial treatment such as hydrolysis, pyrolysis, and derivatization. This chapter describes the structural characterization of chitin and chitosan (as oligomers and polymers) by IR, near-IR, and various types of NMR spectroscopy techniques. This study provides information on (1) composition, sequence, and type of residues and (2) any structural changes occurring in the molecules as a result of different processes (degradation, deacetylation, and acetylation). The influences of acids, alkali, moisture, and impurities on the NMR and IR spectra of the original molecules will be also discussed. 

Park SH, Yoon CS, Kang SG, Kim H-S, Moon S-L Sun Y-K (2004) Synthesis and structural characterization of layered Li[Nii/3Coi/3Mni/3]02 cathode materials by ultrasonic spray pyrolysis method. Electrochim Acta 49 557... 

Bois, L., Maquet, J., Babonneau, F., Mutin, H., and Bahloul, D. Structural characterization of sol-gel derived oxycarhide glasses. 1. Study of the pyrolysis process. 

In previous studies [22, 23] the structural characterization of a series of carbonaceous materials obtained from pyrolysis and subsequent activation of PET waste was conducted by means of N2 and CO2 adsorption isotherms. The gas adsorption data were interpreted by the BET, Dubinin-Asthakov, t-plot and Horvath-Kawazoe methods. For the t-plot method, the standard data given by Selles-Perez [24] for a nonporous active carbon treated at 2073 K, was used. Significant discrepancies between the results from the t-plot method and those obtained from the DR and/or DA methods, applied to both N2 and CO2 adsorption isotherms, were found. 

R-6 Tsuge S. Structural characterization of polymers by pyrolysis-gas chromatography. 71 Anal Chem 1981 1 87-90. 

A novel, soluble trimetallic double alkoxide precursor to potassium aluminosilicate (KAlSi04) has been synthesized by a one pot procedure and its structure characterized. The process termed the oxide one pot synthesis (OOPS) process uses simple, inexpensive chemicals, silica and aluminum hydroxide, to form a processable precursor in one simple step. The precursor is relatively stable to moisture and can be handled in air for long periods of time with minimal hydrolysis. On pyrolysis in air, to 1100" C, it produces phase-pure KAlSi04. The proposed precursor was characterized using thermogravimetric analysis, multinuclearNMR, and mass spectroscopy. The results suggest the precursor disproportionates in solution. 

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