Effect of Boric Acid on the Ionization Equilibrium of α-Hydroxy Carboxylic Acids and the Study of Its Applications

Rong-xiu, Qin; Chen, Haiyan; Wen, Rusi; Li, Guiqing; ZhongLei, Meng

doi:10.3390/molecules28124723

Cited by 3 publications

(10 citation statements)

References 18 publications

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“…Thus, the greater the number of hydroxyl and carboxyl groups, the greater the rate of pH change. However, we also found when mandelic acid, lactic acid, and glycolic acid contained the same number of hydroxyl and carboxylic groups, their pH change rates successively decreased [ 28 ]. However, lactic acid only contains one more methyl group than glycolic acid, which cannot explain why the changes in pH are at different rates.…”

Section: Resultsmentioning

confidence: 99%

“…According to complex configuration analysis and the formation equations of the BA-HCA complexes, it was evident the more types of complexes formed after the addition of BA into the aqueous solution of an ionizable HCA, the more anions were consumed, and the easier it became to shift the ionization equilibrium in the forward direction [ 28 ]. From a thermodynamic perspective, the more types of complexes formed, the greater the increase in entropy, and the easier it was for complexation to occur.…”

Section: Resultsmentioning

confidence: 99%

“…Composite catalysts composed of BA and HCA were found to exert a good synergistic catalytic effect during the catalysis of the esterification reaction of camphene and the hydration reaction of pinene [ 26 , 27 ]. In a previous study [ 28 ], we analyzed and measured the effects of complexation reactions between BA and HCAs on the ionization equilibrium of the HCAs. Eight HCAs were selected to measure the pH changes in aqueous HCA solutions after BA addition [ 28 ].…”

Section: Introductionmentioning

confidence: 99%

“…In a previous study [ 28 ], we analyzed and measured the effects of complexation reactions between BA and HCAs on the ionization equilibrium of the HCAs. Eight HCAs were selected to measure the pH changes in aqueous HCA solutions after BA addition [ 28 ]. We found the composition of the HCA and BA solution had a significant impact on the performance of the catalyst.…”

Section: Introductionmentioning

confidence: 99%

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Complexation of Boronic Acid with Chiral α-Hydroxycarboxylic Acids and the Ability of the Complexes to Catalyze α-Hydroxycarboxylic Acid Esterification

Meng,

Qin,

Wen

et al. 2023

Molecules

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The complexation of boric acid (BA) with various α-hydroxycarboxylic acids (HCAs) was examined by analyzing the change in the optical rotation after the addition of BA to aqueous HCA solutions, and the catalytic properties of the complexes were examined by catalyzing the esterification of the HCAs. The absolute values of the optical rotation of the HCAs increased with increasing BA-to-HCA molar ratio, and the rate of change of the optical rotation gradually decreased as the BA-to-HCA molar ratio increased, reaching a minimum value at a molar ratio of approximately three. As a catalyst, BA could catalyze the acetylation of hydroxyl groups in addition to the esterification of HCAs. Compared to the conventional synthesis routes of ATBC and ATOC, a synthesis route with BA as the catalyst allowed for a lower frequency of catalyst separation and replacement while providing light-colored products. BA could catalyze the formation of triethyl citrate, and the yield of triethyl citrate reached 93.8%. BA could also catalyze the reaction between malic acid and pinene to produce borneol malate. After saponification of borneol malate, borneol was obtained with a yield of 39%.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Complexation of Boronic Acid with Chiral α-Hydroxycarboxylic Acids and the Ability of the Complexes to Catalyze α-Hydroxycarboxylic Acid Esterification

Meng,

Qin,

Wen

et al. 2023

Molecules

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“…Boric acid can increase the concentration of hydrogen ions when added to aqueous HCA solution [ 19 ]; therefore, it may form a composite catalyst with HCA. This study screened HCA–boric composite catalysts through orthogonal experiments with the goal of identifying a catalyst that can enhance the terpinyl acetate yield.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of terpinyl acetate from α-pinene catalyzed by α-hydroxycarboxylic acid–boric acid composite catalyst

Meng,

Qin,

Wen

et al. 2024

PLoS ONE

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To enhance the yield of the one-step synthesis of terpinyl acetate from α-pinene and acetic acid, this study evaluated α-hydroxycarboxylic acid (HCA)–boric acid composite catalysts based on orthogonal experimental design. The most important factor affecting the terpinyl acetate content in the product was the HCA content. The catalytic performance of the composite catalyst was related to the pKa1 of HCA. The tartaric acid–boric acid composite catalyst showed the highest catalytic activity. The α-pinene conversion reached 91.8%, and the terpinyl acetate selectivity reached 45.6%. When boric acid was replaced with B2O3, the HCA composite catalyst activity was enhanced, which reduced the use of HCA. When the lactic acid and B2O3 content accounted for 10% and 4% of the α-pinene mass content, respectively, the α-pinene conversion reached 93.2%, and the terpinyl acetate selectivity reached up to 47.1%. In addition, the presence of water was unfavorable to HCA–boric acid composite catalyst. However, a water content less than 1% of the α-pinene mass content improved the catalytic activity of HCA–B2O3. When the tartaric acid–B2O3 was used as catalyst, and the water content was 1% of the α-pinene mass content, the α-pinene conversion was 89.6%, and the terpinyl acetate selectivity was 47.5%.

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Influence of Organic Acids and Related Organic Compounds on Corrosion Behavior of Stainless Steel—A Critical Review

Abbas,

Adesina,

Suleiman

2023

Metals

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Stainless steel is one of the most commonly used structural materials in industry for the transportation of liquids such as water, acids, and organic compounds. Corrosion is a major concern in industry due to the use of strong mineral acids, feedstock contamination, flow, aqueous environments, and high temperatures. Stainless steel is the most commonly used material in the petrochemical industry because of its characteristics of self-protectiveness, offered by thin passive oxides, and its metallurgical composition. However, chlorides and mineral acids attack the stainless steel continuously, consequently breaking down the passivation film, causing a continuous challenge from corrosion. The corrosion in stainless steel is influenced by many factors including flow rate, temperature, pressure, ethanol concentration, and chloride ion content. This review describes the impact of organic compounds and organic acids on the degradation behavior of stainless steel. The review also summarizes the commonly used organic compounds and their applications. It has been demonstrated that organic acid concentration, temperature, and halide impurities have significant effects on susceptibility to pitting corrosion by damaging the passivation film. The phenomenon of corrosion in stainless steel is quite different in immersion tests and electrochemical potentiodynamic polarization. This review article discusses the importance of organic compounds and their corrosion behavior on steel. The article also puts emphasis on the roles of corrosion inhibitors, monitoring methods, corrosion management, and forms of corrosion.

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Effect of Boric Acid on the Ionization Equilibrium of α-Hydroxy Carboxylic Acids and the Study of Its Applications

Cited by 3 publications

References 18 publications

Complexation of Boronic Acid with Chiral α-Hydroxycarboxylic Acids and the Ability of the Complexes to Catalyze α-Hydroxycarboxylic Acid Esterification

Complexation of Boronic Acid with Chiral α-Hydroxycarboxylic Acids and the Ability of the Complexes to Catalyze α-Hydroxycarboxylic Acid Esterification

Synthesis of terpinyl acetate from α-pinene catalyzed by α-hydroxycarboxylic acid–boric acid composite catalyst

Influence of Organic Acids and Related Organic Compounds on Corrosion Behavior of Stainless Steel—A Critical Review

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