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Pyrolysis study results

The material balance is consistent with the results obtained by OSA (S2+S4 in g/100 g). For oil A, the coke zone is very narrow and the coke content is very low (Table III). On the contrary, for all the other oils, the coke content reaches higher values such as 4.3 g/ 100 g (oil B), 2.3 g/ioo g (oil C), 2.5 g/ioo g (oil D), 2.4/100 g (oil E). These organic residues have been studied by infrared spectroscopy and elemental analysis to compare their compositions. The areas of the bands characteristic of C-H bands (3000-2720 cm-1), C=C bands (1820-1500 cm j have been measured. Examples of results are given in Fig. 4 and 5 for oils A and B. An increase of the temperature in the porous medium induces a decrease in the atomic H/C ratio, which is always lower than 1.1, whatever the oil (Table III). Similar values have been obtained in pyrolysis studies (4) Simultaneously to the H/C ratio decrease, the bands characteristics of CH and CH- groups progressively disappear. The absorbance of the aromatic C-n bands also decreases. This reflects the transformation by pyrolysis of the heavy residue into an aromatic product which becomes more and more condensed. Depending on the oxygen consumption at the combustion front, the atomic 0/C ratio may be comprised between 0.1 and 0.3 ... [Pg.415]

The expulsion of CO from ketocyclohexadienyl radical is also reasonable, not only in view of the data of flow-reactor results, but also in view of other pyrolysis studies [64], The expulsion indicates the early formation of CO in aromatic oxidation, whereas in aliphatic oxidation CO does not form until later in the reaction after the small olefins form (see Figs. 3.11 and 3.12). Since resonance makes the cyclopentadienyl radical very stable, its reaction with an 02 molecule has a large endothermicity. One feasible step is reaction with O atoms namely,... [Pg.134]

Heyns et al. (9) have conducted one of the most extensive studies utilizing glucose that was pyrolyzed at 300°C for four hours or at 500°C for three hours under nitrogen. Approximately 130 compounds were observed. They found that the higher pyrolysis temperature resulted in the formation of aromatic hydrocarbons. Other compound classes identified included aliphatic aldehydes and ketones, furans and oxygenated furans, alcohols, lactones, volatile and nonvolatile acids, and oligosaccharides. [Pg.33]

However, the known difficulties in performing controlled pyrolysis reactions in a laboratory prompted a search for more manageable synthetic procedures. These studies resulted in a detailed investigation of transamination reactions 10,18-15) which have since become one of the most useful methods for the preparation of B-organosubstituted 1,3,2-dia-zaboracycloalkanes (Eq. 4). [Pg.107]

Alkaloids of Delphinium bicolor Nutt.—The structure of Alkaloid A from this plant has been revised on the basis of additional 13C n.m.r. data.24 Alkaloids A and B formerly had been assigned structures (23) and (24), respectively, as a result of a pyrolysis study of Alkaloid A and from 13C n.m.r. data.25 Comparison of the spectra of these alkaloids with those of neoline (10), 8-acetylneoline (25), delphisine (12), trimethoxyneoline (26), heteratisine (27), and 6-acetylheteratisine... [Pg.224]

The expulsion of CO from ketocyclohexadienyl radical is also reasonable, not only in view of the data of flow reactor results, but also in view of other pyrolysis studies [64]. The expulsion indicates the early formation of CO in aromatic... [Pg.110]

Goodings [38] used ethylene dibenzoate as a model compound for pyrolysis studies on PET. His results indicated that an important pyrolytic reaction in molten PET is cleavage of an internal ester linkage to form a carboxylic acid end group and a vinyl ester end group... [Pg.501]

Prior pyrolysis studies on alkaline black liquor from pulping of straw have been developed in our work research group [3], In those studies the processed material was black liquor with 37 % in weight of solids. The experimental system used in that case was a fluidised bed reactor, and the results shown that the main gas product was H2 (about 65% in volume) followed by CO (about 30% in volume). [Pg.255]

In this study results of an extensive experimental activity are presented on the pyrolysis of wood (chips and thick cylinders) for a wide range of external beating conditions and several varieties, namely, two bard-woods (beech, chestnut) and three soft-woods (Douglas fir, redwood and pine). [Pg.1143]

Labscale pyrolysis study examination of the influence of temperature and residence time on the release of metals and resulting mass reduction. [Pg.1418]

Few pyrolysis studies were performed on particular components of bacterial lipopolysaccharides. Py-MS results on KDO were reported [3]. The Py-MS studies on individual lipopolysaccharides may encounter problems caused by the difficulty of obtaining pure compounds from this class. As previously indicated, a significant amount of work has been done on direct Py-MS of a variety of whole microorganisms with the purpose of their rapid identification and classification [3]. [Pg.304]

Pyrolysis does not provide always the desired information on materials from this group. For example, several pyrolysis studies on hemoglobin [15,16], showed that the heme prosthetic group is not revealed in the mass spectrum due to its low contribution to the total mass of the molecule (about 1% [15]), The Py-MS result for hemoglobin from bovine erythrocytes obtained by Curie point pyrolysis at 510° C from a sample applied as a methanol suspension and analyzed by MS with El ionization at 14 eV [15] is shown in Figure 12.4.1. [Pg.395]

Copolymers are very common synthetic materials, and a significant number of pyrolysis studies reported in literature are dedicated to copolymers. Pyrolysis results for different copolymers are discussed in connection to each homopolymer class. Also, a considerable number of literature references is given in the book for each subject. [Pg.2]

Pyrolysis studies were conducted on JP-10 and also on related compounds that are potential products of JP-10 pyrolysis. Figure 9.1 shows a series of methane Cl mass spectra of the material leaving the flow-tube reactor, after JP-10 has passed through at different temperatures. This is a new set of spectra, taken with better control over the ion source conditions. The spectra were actually scanned over a mass range up to more than twice the JP-10 maiss (136) to check for adducts or species that might result from polymerization on the flow-tube walls. Only the range up to mass 140 is plotted, as no significant peaks are... [Pg.356]

Table III shows the effect of shifting furnace operation from propane fresh feed to ethane. Data are from Schutt and Zdonik (54). The reduction of propylene yield from ethane to negligible levels in favor of increased ethylene production cannot be done if a plant has propylene commitments. Because propylene requirements cannot be satisfied with ethane feed, Ericsson (14) has concluded that propane will continue to be the preferred feedstock to make ethylene. Actually, 85% of the U.S. ethylene plants are located in the Gulf Coast area so that they can obtain and operate on economical ethane and propane feeds. The need for propane pyrolysis has resulted in a renewal of experimental interest in this area, and in-depth studies have been made by Crynes and Albright (17) and by Buekens and Froment (7). Table III shows the effect of shifting furnace operation from propane fresh feed to ethane. Data are from Schutt and Zdonik (54). The reduction of propylene yield from ethane to negligible levels in favor of increased ethylene production cannot be done if a plant has propylene commitments. Because propylene requirements cannot be satisfied with ethane feed, Ericsson (14) has concluded that propane will continue to be the preferred feedstock to make ethylene. Actually, 85% of the U.S. ethylene plants are located in the Gulf Coast area so that they can obtain and operate on economical ethane and propane feeds. The need for propane pyrolysis has resulted in a renewal of experimental interest in this area, and in-depth studies have been made by Crynes and Albright (17) and by Buekens and Froment (7).
The overwhelming majority of results listed in Table 16 have been obtained by the methods outlined above and sometimes described as low-temperature photolysis experiments, by which is meant that the radical source is photolytic and the mean experimental temperature (T ) is below 700°K. Quite recently, higher temperature data (T, — 1000°K) have been obtained for methyl [220] and ethyl [221] H-abstrac-tion reactions from alkanes from pyrolysis studies of the alkanes in flow systems. The rate coefficients so obtained for the reaction... [Pg.63]

Analytical pyrolysis of organic matter waste materials has seen similar applications to of organic matter present analyses in water, soil, and air. Similar pyrolysis products evolve from the pyrolysis of waste materials. Pyrolysis studies have also been used to investigate the organic matter present in wastewater from sewerage treatment plants (Page, unpublished results) and wastewater derived from landfill seepage and chlorinated sediments. [Pg.305]

Anthracene dimers as well as dihydroanthracene have been identified as initial reaction products in all pyrolysis studies of anthracene. As shown in Chart I, 11 dimers from anthracene are possible. Because the 9-position is the most reactive, one might expect a predominance of the 9,9 -dimer. However the 2,9-dimer was reported as the major product in one study (18). Many of the other possible dimers were also obtained, depending on the reaction conditions employed. Both steric effects and reactivity factors must, therefore, be taken into account for considering the possible reaction products in aromatic hydrocarbon pyrolysis. The results for anthracene show how the lack of a functional group and the nonspecificity for molecular recombination lead to complex product mixtures in aromatic pyrolysis. [Pg.276]

Table 111-4, modified and updated from similar tables presented by Chortyk and Schlotzhauer (722) and by Baker (171a), summarizes the major precursor relationships proposed and/ or demonstrated to date between tobacco leaf components and tobacco smoke components. These proposals are based in part on the results of a great variety of pyrolysis studies. In some cases, the validation of the proposals is based on the results obtained by addition of leaf components to tobacco and assessing the effect on the levels of specihc MSS components when the spiked tobacco is actually smoked in a... [Pg.219]

Most pyrolysis studies with tobacco, tobacco extracts, extract fractions, individual components, and tobacco additives are performed in a nitrogen atmosphere. This procedure has often been criticized on the grounds that many of the toxic constituents formed during smoking of tobacco products occur as a result of combustion in air rather than in a nitrogen atmosphere. This criticism, however, cannot... [Pg.811]

In 1969, Jones and Schmeltz reported catechol as the major pyrolysis product (32%) from free caffeic acid (1981) and stilbene as the major pyrolysis product from trans-cinmmic acid (1983). trans-Cinnamic acid pyrolysate also contained low yields of several bicyclic and tricyclic PAHs. The results of these and similar pyrolysis studies with tobacco acids were reviewed by Chortyk and Schlotzhauer (722). [Pg.1130]

From his pyrolysis study on cocoa, Schlotzhauer (3447) reported that his results suggested ... [Pg.1139]

During 1969, Rathkamp and Hoffmann (3086) reported on the inhibition of the pyrosynthesis of several selective smoke components. They snggested from the results of their pyrolysis studies on tobacco containing KNO3 or I2 that PAHs are at least partially formed via C and H free radicals. [Pg.1240]


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Pyrolysis studies

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