An investigation of the oxidation mechanism of abietic acid using two-dimensional infrared correlation spectroscopy

Ren, F.; Zheng, Yanfei; Liu, Xiongmin; Yue, Xin-Yin; Ma, Lan; Li, Weiguang; Lai, Fang; Jialing, Liu; Guan, Wen‐Long

doi:10.1016/j.molstruc.2014.12.055

Cited by 34 publications

(26 citation statements)

References 41 publications

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“…Additionally, the MC specimen shows a decrease in the current density on the cathodic branch as well as a larger β C , thus indicating a decrease in the oxygen reduction reaction, likely caused by the oxidation of colophony. 76 This behavior is also shown by the CBS, which corroborates the FT-IR results; however, it is more significant in SCPS, attributed to the high alkalinity causing increased deprotonation of abietic acid and allowing for a higher degree of oxidation. 76 Figure 14a shows the E corr values of carbon steel rebar immersed in 0.4 wt % Cl − contaminated solutions at pH 6.8, 9.1, and 12.6.…”

Section: The Diffusion For the Corrosion Inhibitor (supporting

confidence: 78%

“…76 This behavior is also shown by the CBS, which corroborates the FT-IR results; however, it is more significant in SCPS, attributed to the high alkalinity causing increased deprotonation of abietic acid and allowing for a higher degree of oxidation. 76 Figure 14a shows the E corr values of carbon steel rebar immersed in 0.4 wt % Cl − contaminated solutions at pH 6.8, 9.1, and 12.6. The corrosion protection of free NaNO 2 inhibitors and colophony MCs containing NaNO 2 can be observed by the higher potentials maintained for all pH solutions tested.…”

Section: The Diffusion For the Corrosion Inhibitor (supporting

confidence: 78%

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pH-Triggered Release of NaNO₂ Corrosion Inhibitors from Novel Colophony Microcapsules in Simulated Concrete Pore Solution

Ress

Martin

Bosch

et al. 2020

ACS Appl. Mater. Interfaces

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Herein, pH-sensitive microcapsules containing NaNO 2 corrosion inhibitors for protection of steel reinforced concrete were synthesized via water-in-oil-in-water (W/O/W) double emulsion using colophony as the wall material. The average microcapsule size was 79.07 μm in diameter and exhibited a high encapsulation efficiency of 83.2%. Study of the release of corrosion inhibitors from microcapsules in deionized water (DI water, pH 6.8), carbonate/bicarbonate buffer solution (CBS, pH 9.1), and simulated concrete pore solution (SCPS, pH 12.6) demonstrates that the microcapsules are sensitive to pH and display higher release in alkaline media. This is the first study of colophony as an encapsulating agent for corrosion inhibitors. Furthermore, the alkaline pH-triggered release shows the suitability of its use in reinforced concrete systems. A wide thermal stability range was also found for the colophony microcapsules up to 100 °C. These high pH environments (CBS and SCPS) present pH values above the pK a of colophony (7.2), thus triggering enhanced inhibitor release by the ionization and deprotonation of colophony shell. The higher release in CBS and SCPS is demonstrated by the increases of the corrosion inhibitor diffusion coefficient by an order of magnitude from 3.30 × 10 −17 m 2 /s in DI water up to 1.66 × 10 −16 m 2 /s for SCPS. The release performance indicates that the proposed approach can be used to encapsulate a variety of inhibitors for the protection of steel reinforcements. After immersion in different pH solutions, the corrosion potentials of a carbon steel substrate with microcapsules containing nitrite were more noble than when immersed without microcapsules and the corrosion current densities showed comparable values to free corrosion inhibitors. The formation of a passive ferric oxide layer was confirmed by electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy.

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Section: The Diffusion For the Corrosion Inhibitor (supporting

confidence: 78%

Section: The Diffusion For the Corrosion Inhibitor (supporting

confidence: 78%

pH-Triggered Release of NaNO₂ Corrosion Inhibitors from Novel Colophony Microcapsules in Simulated Concrete Pore Solution

Ress

Martin

Bosch

et al. 2020

ACS Appl. Mater. Interfaces

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“…This necessity results from the fact that aerobic self‐oxidation of abietanes is indeed a characteristic feature that has long been known but not wholly recognized due to its complexity and lack of selectivity . Its exact course is also still unknown, and hydroperoxides and alcohols are not the only products . Among the numerous self‐oxidation products identified, such as peroxides, epoxides, alcohols, and ketones, there are still some unidentified ones.…”

Section: Introductionsupporting

confidence: 65%

“…15 Its exact course is also still unknown, and hydroperoxides and alcohols are not the only products. 16,17 Among the numerous self-oxidation products identified, such as peroxides, epoxides, alcohols, and ketones, there are still some unidentified ones. In this context, the possibility of running the reaction selectively in the desired direction seems to be a subject worthy of a detailed examination.…”

mentioning

confidence: 99%

Research into the oxidation of abietic acid–derived enone with atmospheric oxygen

et al. 2020

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This work presents results of methyl 7‐oxoabiet‐13(14)‐en‐18‐oate (3) self‐oxidation with air‐oxygen in the presence of various bases such as triethylamine or sodium t‐butoxide. While under aerobic conditions, the use of sodium t‐butoxide as a base results in the formation of four isomeric alcohols, an addition of triethylamine into reaction medium directs the enone 3 oxidation to hydroperoxides. To clarify this base dependence and to obtain more in‐depth information about this reaction additional studies with cyclohexenone as a reference enone have been undertaken. Their results demonstrated the predisposition of abietane hydroperoxides to oxidize α,β‐unsaturated ketones to epoxides in the presence of t‐butoxide while reducing the hydroperoxide group to hydroxyl. This ability of hydroperoxides to epoxidize conjugated double bonds and confirmed by the present study intermolecular course allowed proposing a plausible mechanism for this reaction.

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“…The composition of colophony is complex and consists of a variety of resin acids. The main components of the colophony used in this work were abietic acid (AA), palustric acids (PA), neoabietic acids (NA) and dehydroabietic acids (DA), and these compounds were able to undergo isomerization due to the presence of conjugated double bonds, while the CMEs include methyl abietate (MEA), methyl dehydroabietate (MEDA), methyl neoabietate (MENA) and methyl palustrate (MEPA) [ 33 , 34 ]. The catalysis of ZnO/SFCCR with sub-CO 2 promoted the esterification reaction between the carboxyl groups of these acids and the methanol hydroxyl groups, but there have been no reports regarding the methyl esterification reactions of colophony acids or examinations of the complex isomerization and esterification processes.…”

Section: Resultsmentioning

confidence: 99%

Catalytic methyl esterification of colophony over ZnO/SFCCR with subcritical CO ₂ : catalytic performance, reaction pathway and kinetics

et al. 2018

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A heterogeneous catalyst (ZnO/SFCCR) composed of ZnO supported on spent fluid cracking catalyst by wet impregnation was synthesized and applied to the esterification of colophony acids with methanol under subcritical CO2 conditions. The catalyst was characterized by SEM-EDS, BET, ICP, FTIR, XRD and Py-IR. An experimental set-up involving a new injection technique was designed to promote the heterogeneous methyl esterification, and the subcritical CO2 played a role in auxiliary acid catalysis (a pH range of 3.54–3.91), increasing the lifespan of ZnO/SFCCR, reducing the viscosity of the system to promote gas–liquid mass transfer. A maximum conversion rate of 97.01% was obtained in a relatively short time of 5 h. Kinetic experiments were performed from 190 to 220°C using a special high-temperature sampling device and analysing aliquots with high-performance liquid chromatography. A new reaction pathway, involving methyl abietate, methyl dehydroabietate, methyl neoabietate and methyl palustrate along with other kinds of colophony acids, was developed. The kinetic parameters were obtained using the Levenberg–Marquardt nonlinear least-squares method, and the activation energies for the isomerizations of neoabietic and palustric acids and for the methyl esterification of neoabietic, abietic, palustric and dehydroabietic acids were found to be 107.09, 113.95, 68.99, 49.85, 75.43 and 59.20 kJ mol−1, respectively. The results from the kinetic model were in good agreement with experimental values.

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An investigation of the oxidation mechanism of abietic acid using two-dimensional infrared correlation spectroscopy

Cited by 34 publications

References 41 publications

pH-Triggered Release of NaNO₂ Corrosion Inhibitors from Novel Colophony Microcapsules in Simulated Concrete Pore Solution

pH-Triggered Release of NaNO₂ Corrosion Inhibitors from Novel Colophony Microcapsules in Simulated Concrete Pore Solution

Research into the oxidation of abietic acid–derived enone with atmospheric oxygen

Catalytic methyl esterification of colophony over ZnO/SFCCR with subcritical CO ₂ : catalytic performance, reaction pathway and kinetics

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An investigation of the oxidation mechanism of abietic acid using two-dimensional infrared correlation spectroscopy

Cited by 34 publications

References 41 publications

pH-Triggered Release of NaNO2 Corrosion Inhibitors from Novel Colophony Microcapsules in Simulated Concrete Pore Solution

pH-Triggered Release of NaNO2 Corrosion Inhibitors from Novel Colophony Microcapsules in Simulated Concrete Pore Solution

Research into the oxidation of abietic acid–derived enone with atmospheric oxygen

Catalytic methyl esterification of colophony over ZnO/SFCCR with subcritical CO 2 : catalytic performance, reaction pathway and kinetics

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pH-Triggered Release of NaNO₂ Corrosion Inhibitors from Novel Colophony Microcapsules in Simulated Concrete Pore Solution

pH-Triggered Release of NaNO₂ Corrosion Inhibitors from Novel Colophony Microcapsules in Simulated Concrete Pore Solution

Catalytic methyl esterification of colophony over ZnO/SFCCR with subcritical CO ₂ : catalytic performance, reaction pathway and kinetics