Non-reversible reaction

In aqueous or alcoholic solution, certain alkylazoles react with bases to give traces of anions of type (367). With suitable electrophilic reagents, these anions undergo reasonably rapid and essentially non-reversible reaction. 

Interaction with a chemical indicator Can be highly specific, if suitable indicator. Can measure total exposure over time (dosimetry), if a non-reversible reaction is used. Can allow operation at a convenient wavelength, when gas has no convenient absorption in that spectral range. Poisoning can occur, and is easily fouled. Sensitive to groups of chemicals, e.g. acid gases, rather than to a specific gas. May exhibit non-reversible behaviour, which, in many cases, may be undesirable. May need water vapour present, to act as a catalyst, if dry reaction is too slow. 

The [47r(ketone)-27T (silene)] reaction mode is dominant for the alkyl substituted silenes 149 and 150 The initially formed product is 479, which isomerizes in the dark in a non-reversible reaction to the siloxetane 480 (equation 159)235. 

The solid materials obtained by these methods are always governed by the general thermodynamic laws represented by the phase diagrams. In contrast, the methodologies included in the phrase Chimie Douce involve kinetic control of the solid synthesis when non-reversible reactions are used. Therefore, solids prepared by this route are not the most... 

The proposed halorhodopsin photocycle is shown in Fig. 6. In this protein the Schiff base of L does not deprotonate (except as a side reaction, cf. below), but a chloride-dependent equilibrium is established, within a few milliseconds, between L and a red-shifted 0-like state [120-123]. From the kinetics it is inferred that the 0-+L back-reaction is accompanied by uptake of a chloride ion [120,121,123]. Decay of O by a non-reversible reaction regenerates halorhodopsin in tens of milliseconds, but to balance the loss of the chloride it is assumed that first the chloride-free form, HR, is formed, which produces the original state after uptake of chloride on a time scale too rapid to measure. In the absence of chloride the L state is not observed [55,121] it appears that O is directly produced in a truncated photocycle. In the presence of nitrate, an anion poorly transported by halorhodopsin from H. halobium, both photocycles are seen simultaneously. Halorhodopsin from Natronobacterium pharaonis transports nitrate as well as chloride, and in this system O cannot be detected in the photocycle [54]. 

Hydrogen transfer represents a non-reversible reaction with a quantum yield dose to 100%, i.e., there is no return to the enol geometry after the fast formation of the keto product. Calculations of wavepacket propagation in the Sj state, assuming harmonic potentials for the modes contributing to... 

The reactive uptake coefficient F for the non-reversible reaction is given by the relationship (Fogg 2003) ... 

Adenosine triphosphate, ATP, phosphorylates glncose as it enters the living cell according to reaction (11.36), which can alternatively be written as (11.37). In this non-reversible reaction in which ATP acts as the phosphorylating agent, the enzyme is given a special name hexokinase (Fignre 11.14). Enzymes which catalyse transfers specifically to and from ATP (or other nucleotides) are sometimes called phosphokinases. 

Chemical corrosion is when the bonds in the polymer are broken by a chemical reaction with the polymer s environment. During this process the polymer may become embrittled, softened, charred, delaminated, discoloured or blistered these are usually non-reversible reactions. A correct curing procedure of the polymer is important to reduce these degrading effects. 

The characteristic of (5.59) is that it contains trace amounts of reducing agent in the equilibrium of medium, which is almost a non-reversible reaction. Equation (5.60) is an endothermic reaction. When the temperature increases, the equilibrium will move to the right direction. The content of CO and H2 in mixture of equilibrium will decrease. Equation (5.61a) is an endothermic reaction, while (5.61b) is an exothermic reaction. 

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