Organic substances, stability

This is an essential topic for biochemists and biochemical engineers. Biochemical reactions involve both cellular and enzymatic processes, and the principal differences between biochemical and chemical reactions lie in the nature of the living systems. Biochemists and biochemical engineers can stabilize most organic substances in processes involving microorganisms. 

Mineral Colloid-Organic Substance-Microorganism Interactions in Relation to Soil Structural Stability... 

Despite its unsaturated nature, benzene with its sweet aroma, isolated by Michael Faraday in 1825 [1], demonstrates low chemical reactivity. This feature gave rise to the entire class of unsaturated organic substances called aromatic compounds. Thus, the aromaticity and low reactivity were connected from the very beginning. The aromaticity and reactivity in organic chemistry is thoroughly reviewed in the book by Matito et al. [2]. The concepts of aromaticity and antiaromaticity have been recendy extended into main group and transition metal clusters [3-10], The current chapter will discuss relationship among aromaticity, stability, and reactivity in clusters. 

It is operationally difficult to distinguish between dissolved and colloidally dispersed substances. For example, colloidal metal-ion precipitates occasionally have particle sizes smaller than 100 A, sufficiently small to pass through a membrane filter, and organic substances can exist as a stable colloidal suspension. Information on the types of species encountered under different chemical conditions (type of complexes, their stabilities, rate of formation) is a prerequisite to better understanding of the transformation in properties of toxic chemicals in a water body. 

The composition of the surface-bound species must be considered they contribute to the stability of the dispersions of metal nanoparticles. In the case of electrostatically stabilized dispersions, the techniques to measure the interfacial electronic phenomena, including electrophoresis, electroosmosis, etc., are useful (54). In order to understand the composition (as well as structures) of the chemical species bound in the surface of metal particles, spectroscopic measurements used for common organic substances are used as well as the elemental analysis. 

The term biochemical stabilization refers to the biotic or abiotic production of organic substances that are refractory to decomposition by microorganisms and contribute, through condensation and complex formation, to the stabilization of otherwise easily decomposable substrates such as enzymes. This stabilization process coincides with the process of humification. 

The first question to be answered is whether or not the sample is volatile enough to be analyzed by GC. GC columns are currently available with upper temperature limits of around 350 °C. Hence, compounds should be sufficiently volatile at this temperature to be analyzed by GC. A second requirement for the sample, which becomes the more relevant the higher the temperatures used, is the thermal stability of the sample, both in the column, as well as in the injector, which in conventional GC is operated at a temperature slightly above that of the column. Because of the limited stability of organic substances at higher temperatures, extremely high temperatures do not seem to be very... 

Finally, in some of the most widely used classical models - the free-volume models of Fujita, Vrentas and Duda and their alternatives (171-175) - more than a dozen structural and physical parameters are needed to calculate the free-volume in the penetrant polymer system and subsequently the D. This might prove to be a relatively simple task for simple gases and some organic vapors, but not for the non-volatile organic substances (rest-monomers, additives, stabilizers, fillers, plasticizers) which are typical for polymers used in the packaging sector. As suggested indirectly in (17) sometimes in the future it will maybe possible to calculate all the free-volume parameters of a classical model by using MD computer simulations of the penetrant polymer system. 

It is known that phosphorus (+5) oxide actively reacts with water vapor. It is an effective chemisorbent of water, and it can be used for drying of gases. Phosphoric acid is formed however, and regeneration is very difficult. It was created as a sorbent on silica with P-oxide nanolayer. It is an active sorbent of water vapor and it is 5-6 times better than initial silica (at a humidity of 70%). It also adsorbs ammonia, and some organic substances. Its name in industry is P-1-3. The sorbents IVS-1 and P-1-3 are used in industry for clearing and stabilization of the gas atmosphere in devices. 

---