Factors affecting inhibitor efficiency

FACTORS AFFECTING INHIBITOR EFFICIENCY 2.2.1 Electron directing and steric effects solvents... 

The efficiency of a particular amine must depend not only on the rate of the initial hydrogen abstraction, but also on the nature and subsequent reactions of the radical produced. The free radical produced by H transfer may well be stabilised by resonance and may be insufficiently reactive to start a new oxidation chain [40], particularly when the amino group is surrounded by bulky substituents [9]. If the radical does react, then the subsequent rate and nature of the reaction will depend upon the intermediates and on the relative importance of chain termination and chain transfer reactions. Some formal grouping of the factors affecting the efficiency of a given inhibitor and the kinetics of the inhibited reaction is possible. 

Before undertaking a program of evaluating inhibitors for effectiveness in mitigating corrosion, one must review the overall problem and determine what is required of the inhibitor, that is, exactly what parameters are to be tested and what factors affect test results. These questions and their answers will help in obtaining meaningful data for selection of the most efficient inhibitor in the environment of interest. The first step is to select the critical environmental conditions of interest and to incorporate them in the test. 

The production of pharmaceutical proteins in plants has clear advantages over traditional systems in terms of cost-efficiency and product safety, since there is no risk of contamination with human pathogens. Furthermore plants are much less likely than mammalian cells to be affected by the expression of certain human proteins, such as growth factors and cell cycle inhibitors [29]. Therefore, plants provide a strategic complement to existing microbial and animal production systems. 

In general, the factors that influence the efficiency of the compounds as inhibitors also affect their oxidisability. Thus, for example, studies of... 

All derivatives of the benzo-hydroxamic acid inhibited copper corrosion more effectively than BHA itself. The efficiency was affected much more by hydrophobic bulkiness in the phenyl ring than by the electronpushing or electron-attracting character of the substituents. The results attained by electrode impedance spectroscopy and quartz crystal nanobalance techniques led to recognition that the higher efficacy was not due to the inductive effect of the substituents, as both chloro and methyl substitution led to enhanced inhibition. The most important factor is the hydrophobic bulkiness. In the inhibition process, the inhibitor molecule is attached to the copper surface by the polar group (CON"), and the apolar hydro-phobic moiety may block the metal surface... 

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