The Chemistry of Carbonization

In most cases, gas evolution has been observed as a function of temperature, and the gases have been analyzed, either by gas chromatography or by mass spectroscopy. 

CO2 is second in abundance (7-12%) it is evolved in the temperature range where fragmentation of unladdered polymer is assumed to be the main effect. It was suggested by Simitzis that CO2 results mainly from the decomposition of side 

NHj (6-8%) is assumed to be formed from imino end groups of cyclized sequences, with concomitant aromatization of a ring (Hay )  

CH stems most probably from the fragmentation of unladdered parts, as well as from comonomer side chains. It is present only in small amounts. 

Finally, Nj starts to evolve at temperatures over 600 °C intermolecular elimination from relatively stable, N containing, aromatic structures, with ring condensation, may safely be assumed to be the cause  

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There is the possibility of building up an extensive systematic chemistry of compounds containing boron-nitrogen bonds, analogous to the chemistry of carbon-carbon bonds but the reactivity of the B—bond is much greater than that of the C—C bond, so that we get physical, but not chemical, resemblances between analogous compounds. 

The concept of oxidation states is best applied only to germanium, tin and lead, for the chemistry of carbon and silicon is almost wholly defined in terms of covalency with the carbon and silicon atoms sharing all their four outer quantum level electrons. These are often tetrahedrally arranged around the central atom. There are compounds of carbon in which the valency appears to be less than... 

One of the cornerstones of the chemistry of carbon compounds (organic chemistry) is Kekule s concept, proposed in 1858, of the tetra-valence of carbon. It was independently proposed in the same year by Couper who, however, got little recognition (vide infra). Kekule realized that carbon can bind at the same time to not more than four other atoms or groups. It can, however, at the same time use one or more of its valences to form bonds to another carbon atom. In this way carbon can form chains or rings, as well as multiple-bonded compounds. 

Henrici-Olive, G. and Olive, S. The Chemistry of Carbon Fiber Formation from Polyacrylonitrile. Vol. 51, pp. 1—60. 

Abstract Many similarities between the chemistry of carbon and phosphorus in low coordination numbers (i.e.,CN=l or 2) have been established. In particular, the parallel between the molecular chemistry of the P=C bond in phosphaalkenes and the C=C bond in olefins has attracted considerable attention. An emerging area in this field involves expanding the analogy between P=C and C=C bonds to polymer science. This review provides a background to this new area by describing the relevant synthetic methods for P=C bond formation and known phosphorus-carbon analogies in molecular chemistry. Recent advances in the addition polymerization of phosphaalkenes and the synthesis and properties of Tx-con-jugated poly(p-phenylenephosphaalkene)s will be described. 

The chemistry of a carbon(-f) centre is best looked at through the chemistry of carbon in a ketone or an aldehyde which we can write... 

The chemistry of carbon, known as organic chemistry, has i already been discussed. The element silicon, also in Group IV, is just as significant in the mineral world as carbon is in the world of living things. Silicon is the second most abundant element in the earth s crust (oxygen is the most abundant). 

The chemistry of carbon, and radiocarbon, in the atmosphere represents one of the most important areas of environmental research today. The primary practical reason for this is the increasing attention which must be paid to the critical balance between energy and the environment, especially from the viewpoint of man s perturbations of natural processes and his need to maintain control. Probably more than other species, carbonaceous molecules play a central role in this balance. Some of the deleterious effects of carbonaceous gases and particles in the atmosphere are set down in Table 3. The potential effects of increased local or global concentrations of these species on health and climate have led to renewed interest in the carbon cycle and the "C02 Problem". It should be evident from the table, however, that carbon dioxide is not the only problem. In fact, the so-called "trace gases and particles" in the atmosphere present an important challenge to our interpretation of the climatic effects of carbon dioxide, itself [20]. 

Our goal in this chapter is to help you learn about organic chemistry, the chemistry of carbon. You will learn about the different types of organic compounds. We will also discuss biochemistry, including some biologically important compounds, such as proteins, carbohydrates, and so on. We will also familiarize you with some organic reactions. And finally, to do well, you must Practice, Practice, Practice. 

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