Thermal decomposition of carbon

As chlorination proceeds from methyl chloride to carbon tetrachloride, the length of the C—Cl bond is decreased from 0.1786 nm in the former to 0.1755 nm in the latter (3). At ca 400°C, thermal decomposition of carbon tetrachloride occurs very slowly, whereas at 900—1300°C dissociation is extensive, forming perchloroethylene and hexachloroethane and Hberating some chlorine. Subjecting the vapor to an electric arc also forms perchloroethylene and hexachloroethane, as well as hexachlorobenzene, elementary carbon, and chlorine. 

Holmium oxide is prepared by thermal decomposition of carbonate, oxalate, hydroxide, nitrate, sulfate, or any oxo salt of holmium ... 

Radushkevich LV, Lukyanovich VM (1952) About structure of carbon created at thermal decomposition of carbon monoxide on iron contact. J Phys Chem 26 88-95... 

Vapor binding, or air lock, is another common cause of household radiator malfunction. Often, the vapor accumulating in the radiator is CO,2, rather than air. The C02 originates from the thermal decomposition of carbonates in the boiler. Regardless, air and C02 form a noncondensable vapor in the radiator. These noncondensables mix with the steam in the radiator. The noncondensables then reduce the concentration of the steam, by dilution. The diluted steam has a lower partial pressure than pure steam. The lower the partial pressure of the steam, the more difficult it is to condense. As the rate of condensation of the steam drops, so does the heat radiated by the radiator. 

Some reactions are brought about by the action of heat alone, for example the thermal decomposition of carbonates, and baking bread and other materials. These constitute a special class of solid reactions somewhat akin to the progressive conversion type of reaction models but with the rate limited by the rate of heat penetration from the exterior. 

The discussion of the high-temperature properties and thermal decomposition of carbonates in this chapter, a plan which will be followed for other classes of compounds in subsequent chapters, is given for each element. A brief discussion is followed by quantitative data on phase transitions, densities, and thermodynamic parameters for the carbonate, the corresponding oxide, and the decomposition reaction MC03 = MO + C02. If the carbonate and oxide are solids and form no solid solution, the equilibrium constant is the pressure of C02 which would be obtained if one begins with an evacuated container and lets the system come to equilibrium. In this case, the pressure is a unique function of the temperature. As pointed out in Chapter 1, this is no longer true... 

Figure 9.3 Conversion of thermal decomposition of carbon dioxide in a dense yttria-stabilized zirconia membrane reactor as a function of membrane thickness when a sweep gas is used (top) and when vacuum is applied (bottom) [Itoh et al., 1993]...

First of all, the space time defined in Eq. (11-5) or (11-6) depends on the volume of the reactor and the total volumetric feed rate. Thus, for a given reactor volume, space time is inversely proportional to the total feed rate. Itoh et al. [1993] studied the use of a dense yttria-stabilized zirconia membrane reactor for thermal decomposition of carbon dioxide. The reactor temperature was not kept constant everywhere in the reactor but varying with the reactor length instead. The resulting temperature profile is parabolic with the maximum temperature at the midpoint of the reactor length. This nonisothermal... 

The heat generated in the reaction causes thermal decomposition of carbonic acid to gaseous carbon dioxide and water ... 

PZC/IEP of CO3O4 Obtained by Thermal Decomposition of Carbonate Decomposition... 

Oxygen forms binary compounds with nearly all elements. Most may be obtained by direct reaction, although other methods (such as the thermal decomposition of carbonates or hydroxides) are sometimes more convenient (see Topic B6). Oxides may be broadly classified as molecular, polymeric or ionic (see Topics B1 and B2). Covalent oxides are formed with nonmetals, and may contain terminal (E=0) or bridging (E-O-E) oxygen. Especially strong double bonds are formed with C, N and S. Bridging is more common with heavier elements and leads to the formation of many polymeric structures such as Si02 (see Topics FT and F4). 

The long time intervals that separate the deposition of marine carbonates and the return of volcanic CO2, i.e. the above reaction in reverse, as a result of the thermal decomposition of carbonates deep within the lithosphere, can lead to an imbalance in atmospheric CO2 concentrations. 

Another source of CO2 can be thermal decomposition of carbonate minerals, or their destruction by acid waters during the oxidation of sulphide ores. 

L Vov BV (2002) Mechanism and kinetics of thermal decomposition of carbonates. Thermochim Acta 386 1-16... 

Carbon dioxide acid -1- carbonate/hydrogencarbonate salt -i-water -i- carbon dioxide Thermal decomposition of carbonate/ hyd rogenca rbonate... 

I2 + Q. and potassium carbonate at ca. 310 °C (- KF + CO + Q, study of which has led to the value 448.5 kJ mol- for the C—F bond energy [the C—F bond energy in poly(carbon monofluoride) of stoichiometry CFi.ij is reported to be ca. 480 kJ mol ]. Obviously, thermal decomposition of carbon monofluoride in the presence of suitable substrates might prove an interesting, if not useful, source of some fluorinated organic, organometallic, or organometalloidal compounds. 

Carbon dioxide, the other important oxide of carbon, earns the rank of seventeenth among chemicals produced. It is recovered mainly as a by-product of other processes, for example, the thermal decomposition of carbonates and the fermentation of carbohydrates. 

In the present work, essentially all carbon species were removed leaving pure silicon nitride. When the deposition was conducted in hydrogen, however, Si-C bonds in the precursor were only partially ruptured, with the concomitant formation of silicon carbonitride (Fig. 6a). Since the Si-to—C ratio in methylsilazane is unity, the low carbon composition of the films, about 9%, estimated from the peak to peak height, indicates that reactive hydrogen also promotes thermal decomposition of carbon—related bonds in the precursor. The atomic composition of each elements remained uniform throughout the film thickness. The relative atomic composition does not appear to be dependent on the deposition temperatures as shown in Fig. 7. 

The rare earth dioxymonocarbonate (abbreviated oxycarbonate) is formed as a stable intermediate during the thermal decomposition of carbonate hydrates in air. The decomposition reaction leading to oxycarbonate may have one or two steps as described earlier. Thermoanalytical studies have established that the thermal decomposition of rare earth oxalates in an air or COj atmosphere is another simple way to prepare oxycarbonates (Ropp and Gritz, 1965). The decomposition of rare earth formates likewise leads to oxycarbonates (Petru et al., 1966). 

Recently, greater attention has been focused on COg capture and sequestration. One potential route for the consumption of COg is the thermal decomposition of carbon dioxide to CO and Og, because CO can be utilized as a raw material in the synthesis of important basic... 

Fio. 22-4c. Thermal process (thermal decomposition) of carbon-black manufacture. 

Prasad, R. M., Mera, G., Morita, K., Muller, M., Kleebe, H. J., Gurlo, A. et al. (2012). Thermal decomposition of carbon-rich polymer-derived silicon carbonitrides leading to ceramics with high specific surface area and tunable micro- and meso-porosity. Journal of the European Ceramic Society, 32(2), 477-484. doi 10.1016/j. jeurceramsoc.2011.08.020. 

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