Pyrolysis references

The pyrolysis process can further be classified into slow- and fast-pyrolysis, referring to the applied heating rates in the process. 

Pyrolysis refers to the decomposition of organic matter by heat in the absence of air. A common synonym for pyrolysis is devolatilization. Thermal decomposition and destructive distillation are frequently used to mean the same. 

Dehydrohalogenation method Quinoline FeCL Pyrolysis Reference... 

The layer to be investigated consists of three oxide films 2, SiC and 2 each with an optical thickness of A74. The layers were taken from an organic solution and transferred to a soda lime glass substrate through pyrolysis. Reference to... 

Starting compounds Reaction type Composition of the ceramic Pyrolysis/ References... 

Three general processes occur simultaneously during tobacco combustion pyrolysis, pyrosynthesis, and distillation. Pyrolysis refers to thermal decomposition of the organic leaf components into smaller molecules. Being partially unstable chemically, some of these newly formed fragments can recombine to form additional components (pyrosynthesis). Both pyrolysis and pyrosynthesis result in the presence of chemical species in tobacco... 

Polymer pyrolysis refers to the pyrolytic decomposition of metal-organic polymeric compounds to produce ceramics. The polymers used in this way are commonly referred to as preceramic polymers in that they form the precursors to ceramics. Unlike conventional organic polymers (e.g., polyethylene), which contain a chain of carbon atoms, the chain backbone in preceramic polymers contains elements other than carbon (e.g., Si, B, and N ) or in addition to carbon. The pyrolysis of the polymer produces a ceramic containing some of the elements present in the chain. Polymer pyrolysis is an extension of the well-known route for the production of carbon materials (e.g., fibers from pitch or polyacrylonitrile) by the pyrolysis of carbon-based polymers (54). It is also related to the solution sol-gel process described in the previous section where a metal-organic polymeric gel is synthesized and converted to an oxide. 

Pyrolysis is a synonym for cracking and is the process of thermally degrading a material in the absence of O2. Specifically, the use of the term pyrolysis refers to plastic-to-fuel (PTF) technologies that handle scrap plastic through a process of thermal... 

Thioketenes can be prepared in several ways, from carboxyHc acid chlorides by thionation with phosphoms pentasulfide [1314-80-3] 2 5 ketene dithioacetals by -elimination, from l,2,3-thiadia2oles with flash pyrolysis, and from alkynyl sulfides (thioacetylenes). The dimeri2ation of thioketenes to 2,4-bis(alkyHdene)-l,3-dithietane compounds occurs quickly. They can be cleaved back pyrolyticaHy (63). For a review see Reference 18. 

An excess of crotonaldehyde or aUphatic, ahcyhc, and aromatic hydrocarbons and their derivatives is used as a solvent to produce compounds of molecular weights of 1000—5000 (25—28). After removal of unreacted components and solvent, the adduct referred to as polyester is decomposed in acidic media or by pyrolysis (29—36). Proper operation of acidic decomposition can give high yields of pure /n j ,/n7 j -2,4-hexadienoic acid, whereas the pyrolysis gives a mixture of isomers that must be converted to the pure trans,trans form. The thermal decomposition is carried out in the presence of alkaU or amine catalysts. A simultaneous codistillation of the sorbic acid as it forms and the component used as the solvent can simplify the process scheme. The catalyst remains in the reaction batch. Suitable solvents and entraining agents include most inert Hquids that bod at 200—300°C, eg, aUphatic hydrocarbons. When the polyester is spHt thermally at 170—180°C and the sorbic acid is distilled direcdy with the solvent, production and purification can be combined in a single step. The solvent can be reused after removal of the sorbic acid (34). The isomeric mixture can be converted to the thermodynamically more stable trans,trans form in the presence of iodine, alkaU, or sulfuric or hydrochloric acid (37,38). 

Of the many forms of carbon and graphite produced commercially, only pyrolytic graphite (8,9) is produced from the gas phase via the pyrolysis of hydrocarbons. The process for making pyrolytic graphite is referred to as the chemical vapor deposition (CVD) process. Deposition occurs on some suitable substrate, usually graphite, that is heated at high temperatures, usually in excess of 1000°C, in the presence of a hydrocarbon, eg, methane, propane, acetjiene, or benzene. 

Soot. Emitted smoke from clean (ash-free) fuels consists of unoxidized and aggregated particles of soot, sometimes referred to as carbon though it is actually a hydrocarbon. Typically, the particles are of submicrometer size and are initially formed by pyrolysis or partial oxidation of hydrocarbons in very rich but hot regions of hydrocarbon flames conditions that cause smoke will usually also tend to produce unbumed hydrocarbons with thek potential contribution to smog formation. Both maybe objectionable, though for different reasons, at concentrations equivalent to only 0.01—0.1% of the initial fuel. Although thek effect on combustion efficiency would be negligible at these levels, it is nevertheless important to reduce such emissions. 

Pyrolysis of alkanes is referred to as eraeking. Alkanes from the paraffins (kerosene) fraetion in the vapor state are passed through a metal ehamher heated to 400-700°C. Metallie oxides are used as a eatalyst. The starting alkanes are broken down into a mixture of smaller alkanes, alkenes, and some hydrogen. 

The unit of the veloeity eonstant k is see Many reaetions follow first order kineties or pseudo-first order kineties over eertain ranges of experimental eonditions. Examples are the eraeking of butane, many pyrolysis reaetions, the deeomposition of nitrogen pentoxide (NjOj), and the radioaetive disintegration of unstable nuelei. Instead of the veloeity eonstant, a quantity referred to as the half-life iyj is often used. The half-life is the time required for the eoneentration of the reaetant to drop to one-half of its initial value. Substitution of the appropriate numerieal values into Equation 3-33 gives... 

The results of research into the fluidised bed pyrolysis of plastic wastes are reported, with reference to determining the optimum process conditions for the process with respect to the reactor behaviour. The study investigates the effects of process variables such as bed temperature, polymer feed rate, bed hold-up, fluidising velocity, and size of inert material. Findings illustrate the importance of the knowledge of the hydrodynamics of the fluidised bed and of the interactions between bed and polymer particles in the design and operation of the reactor. 15 refs. 

Experimental conditions are listed in Table 2. After pyrolysis of samples at 1073K, the product char was washed with pure water and chlorine of the leachates was analyzed by ion chromatography. Refer to the reference [3] for a detailed experimental procedure. 

The thermo-gravimetric (TG) and differential thermo-gravimetric (DTG) curves of the gingko nut shell are shown in Fig. 2 where the moisture losses take place up to 200°C followed by the pyrolysis reaction. Then, the major weight loss due to the main degradation occurs at around 360°C. This zone is referred to as the active pyrolysis zone where the evolution of volatile compounds occurs during decomposition of the primary hemi-cellulose and cellulose [5]. 

Over a long time period it may well not be possible to duplicate library cell culture conditions. What happens when the lot of media used in the final culture step prior to pyrolysis has been consumed Can culture media suppliers assure nutritional identity between batches Media types for growth of fastidious strains invariably include natural products such as brewer s yeast, tryptic soy, serum, egg, chocolate, and/or sheep blood. Trace components in natural products cannot be controlled to assure an infinite, invariable supply. The microtiter plate wells used here do not hold much media. Even so, the day will come when all media supplies are consumed and a change in batch is unavoidable. When that happens, if there were no effective way to compensate spectra for the resulting distortions, it would be necessary to re-culture and re-analyze replicates for every strain in the reference library. Until recently the potential for obsolescence was a major disincentive for developing PyMS spectral libraries of bacteria. Why this is no longer an insurmountable problem is discussed in the next section. 

With recent developments in analytical instrumentation these criteria are being increasingly fulfilled by physicochemical spectroscopic approaches, often referred to as whole-organism fingerprinting methods.910 Such methods involve the concurrent measurement of large numbers of spectral characters that together reflect the overall cell composition. Examples of the most popular methods used in the 20th century include pyrolysis mass spectrometry (PyMS),11,12 Fourier transform-infrared spectrometry (FT-IR), and UV resonance Raman spectroscopy.16,17 The PyMS technique... 

It is appropriate to conclude this section by reference to one aspect of the CSIRO flash pyrolysis project involving, again, brown coals. Here, it has been shown (28) that the presence of... 

Further reference to Fig. 6 shows that the latter tar yield now plots with the bituminous coals with reference to the effect of the atomic H/C ratio. Similarly a second brown coal sample (Loy Yang) which, as recovered from the seam, has a very low ash yield (0.4% dry ash-free basis), and most of the carboxyl groups in the acid form, plots with the bituminous coals in Fig. 6 however, when the sodium-salt is produced from this coal before flash pyrolysis the tar yield is almost complete supressed. 

Suggestions of untoward hazard inherent in the preparation of nitrosotrifluoro-methane by pyrolysis of trifluoroacetyl nitrite [1] are discounted in the later reference, which gives full details of the equipment and procedure that had been used uneventfully during the previous decade [2],... 

Another valuable advantage of Raman spectroscopy, which is unique, is its capability of being used to characterise carbon species, in particular graphitic and amorphous carbon this can be of value to many degradation and pyrolysis studies. Perfectly ordered graphite is characterised by a Raman-active vibrational mode that occurs at 1,575 cm-1 this band is usually referred to as the C7 band. With increasing disorder in the carbon, a new band, the D band, appears at... 

For these reasons, when the pyrolysis of samples from works of art is undertaken for the first time, as well as when a new device or a new instrumental set-up is introduced in a laboratory, it is very important to build one s own libraries of chromatographic profiles, based on the analysis of reference materials. 

For the decabromodiphenyl oxide (DBDPO) pyrolysis reactions, two different procedures were used to synthesize the series of brominated diphenyl oxides and dibenozofurans employed as the relative retention time standards AlBr3/Br2 in ethylene dibromide and Fe° (metal)/Br2 in tetrachloroethylene. The rate of the initial bromination steps in the former reaction was so rapid that only the higher degree of bromination adducts could be isolated. The rate of the Fe°/Br2 reaction was found to be much slower, especially during the initial stages, and these reactions yielded a broader range of relative retention time reference peaks. 

The collected data were aimed for the commercial heat treatment of hardboards (24) and for curing processes proposed for some paper grades (4,6,25). They thus refer to quite a mild pyrolysis in air, for a shorter treatment period than some of the data presented here... 

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