Amine Inhibitors Research Articles

Study of Aromatic Amine Inhibitors by Nuclear Magnetic Resonance

Abstract Every and Riggs1,2 have reported the inhibitive properties of aniline and several of its derivatives. They found that the relative inhibitor effectiveness of these compounds was determined by the nature of the substituent group and its position in the aromatic ring. Some of the substituted anilines gave better than 95 percent protection to 1020 mild steel in 10 percent hydrochloric acid; a few of the substituted anilines accelerated the corrosion rate by as much as a factor of two. Differences in molecular area of these compounds were small. The observed corrosion rate could not be attributed to differences in surface area of the metal covered per molecule. No significant relationship was noted between the inhibitive properties and solubility, molecular weight or dipole moment. High resolution nuclear magnetic resonance spectra have been obtained for a group of these amine bases in cyclohexane solution. It was found that there is a linear correlation between the proton resonance frequency of the amine hydrogens and the observed inhibitor characteristics of these compounds.

A study of the efficiency of oxidation inhibitors for rubber at various temperatures

AbstractA kinetic study of the oxidation of butadiene–styrene and butadiene polymers in the presence of secondary aromatic amine inhibitors has been made over the temperature range 70–150°C. The rate of the inhibited oxidation has been found to depend upon the inhibitor concentration. In contrast with other inhibited processes, this relation is described by a curve with a minimum. The concentration corresponding to the latter depends upon the oxidation temperature, polymer reactivity, and lability of the imino hydrogen of the inhibitor molecule. Experimental data and kinetic computation have shown that the extreme on the efficiency–concentration curve is due to the fact that the amine not only exerts a retarding but also an initiating effect on the polymer oxidation process. The latter is due to direct interaction of the amine and molecular oxygen during the inhibited oxidation of the polymer. The kinetics of oxidation of the amine have been investigated. The duration of the induction period of the polymer oxidation process does not increase in proportion with the inhibitor concentration. The relation between the length of the induction period and rate of oxidation of the polymer for various inhibitor contents has been investigated and discussed. The inhibitor concentration exerts a marked influence on the overall rate of structural changes undergone by the polymer in the oxidation process and also on the ratio of the degradation and structuration velocities of the molecular chains. The change in efficiency of the inhibitor with respect to the oxidation temperature has been examined.

Corrosion Inhibitor Evaluation from Cathodic Polarization Measurements

Abstract Investigation described indicates that relative corrosion rates of iron and steel in systems buffered to a pH of 5.0 can be determined from cathodic polarization measurements in the presence of an oil phase, carbon dioxide and commercially used amine inhibitors. Method described provides a rapid and relatively accurate means of evaluating the efficiency of industrial corrosion inhibitors in systems which simulate operating conditions. 5.8.3

Further response of acetylcholinesterase and of conduction in bullfrog sciatic nerve to the stereochemistry of amine inhibitors. II

The stereochemical responses of acetylcholinesterase and bullfrog sciatic nerve to structural variations in the compound sequence I–III have been compared. The enzyme does not differentiate between configurations at the β-carbon atom in Ib, whereas the nerve shows specificity in terms of reversibility of blockade. Both nerve and enzyme show greater sensitivity to blockade by the cis-isomer III than by the trans-species II.

Deuterium isotope effect in inhibited oxidation of butadiene–styrene rubber

AbstractThe importance of hydrogen abstraction by peroxy radicals as a mechanism of antioxidant action in rubber has been studied by investigation of a deuterium isotope effect with amine and phenolic inhibitors in the oxidation of butadiene‐styrene rubber. Deuterium was substituted for the active hydrogen of N‐phenyl‐2‐naphthylamine and 2,6‐di‐tert‐butyl‐4‐methylphenol by reacting the antioxidants with methylmagnesium iodide and then with deuterium oxide. The oxidation rates of butadiene–styrene polymer inhibited with 3 parts per hundred of these compounds were measured and compared with the oxidation rates using normal antioxidants. A kinetic isotope effect in the rate of oxidation was observed with both the phenolic inhibitor (kD/kH = 1.3 with not less than 77% substitution) and the amine inhibitor (kD/kH = 1.8 with not less than 60% substitution). The existence of an isotope effect leads to the conclusion that hydrogen donation to a peroxy radical is a controlling step in the mechanism by which these antioxidants function to retard the oxidation of rubber.

Electrocapillary Action of Corrosion Inhibitors

Indelli and Pancaldi1 and I2 have compared some characteristic phenomena occurring at the interface of a dropping mercury microelectrode and electrolyte solutions with phenomena encountered in corrosion inhibition2. It was found2 that the effectiveness of numerous corrosion inhibitors is reflected in their ability to suppress various polarographic maxima (abnormal current peaks in the current-voltage curves of the mercury microelectrode). In particular, it was shown that the order of relative inhibiting effectiveness of a number of amine inhibitors (for the iron – sulphuric acid system) is the same as that of their effectiveness in suppressing certain polarographic maxima. These amines (both aliphatic and aromatic) were most effective in suppressing maxima corresponding to the negative branch of the electrocapillary curve at which mercury is negatively charged with respect to the solution. This is consistent with Mann's3 conclusion that amines inhibit the corrosion of iron in sulphuric acid by becoming adsorbed on the cathodic areas of this metal. It was thus demonstrated that significant similarities exist between the processes involved in polarographic maxima and their suppression, on one hand, and in metallic corrosion and its inhibition, on the other4. Campbell5 has also employed polarographic techniques in detecting corrosion inhibitors.

アミン系添加剤を加えた塗膜の性能

アミン系添加剤を加えた塗膜の性能

冷凍工業における有機アミン系インヒビターの応用 (第1報)

冷凍工業における有機アミン系インヒビターの応用 (第1報)