Copper-catalyzed sodium tetraphenylborate, triphenylborane, diphenylborinic acid and phenylboronic acid decomposition kinetic studies in aqueous alkaline solutions

Abstract

This work studied the kinetics of copper-catalyzed decomposition of tetraphenylborate, triphenylborane, diphenylborinic acid and phenylboronic acid (NaTPB, 3PB, 2PB and 1PB, respectively) in aqueous alkaline solution over the temperature range of 25 to 70 °C. The statistically designed test matrices added copper sulfate to maximum concentrations of 10 mg/L. The relative rates of decomposition increase in the order of NaTPB < 1PB ~ 3PB < 2PB. Dependence of decomposition on the amount of added copper increases in the order of 3PB ~ 2PB < 1PB ~ NaTPB. Activation energies ranged from 82 to 143 kJ/mole over the temperature range studied. Final decomposition products predominately involved benzene and phenol. All 3PB, 2PB and 1PB intermediate phenylborate species proved relatively stable (< 8% decomposition ) thermal hydrolysis of the phenylborate species occurs at 55 to 70° C in alkaline (0.6-2.3 M OH -, 2-4.7 M Na + ) solution with no added copper. The experiments suggest an important role for oxygen in copper-catalyzed phenylborate decomposition. NaTPB decomposes promptly under anoxic conditions while 3PB, 2PB and 1PB decompose faster in aerobic solutions. Benzene and phenol form as the predominant end-products from alkaline copper catalysis in static systems sealed under air. Both 2PB and 1PB decompose with near equal rates and quantitatively produce phenol under flowing air-purge conditions at 25 to 60 °C. Mechanisms for copper-catalyzed phenylborate decomposition likely involve a redox process giving loss of a phenyl group from the phenylborate with reduction of cupric ion, or dephenylation by reduced cuprous ion involving a phenylated copper intermediate.

Boron‐ and Iron‐Incorporated α‐Co(OH)2 Ultrathin Nanosheets as an Efficient Oxygen Evolution Catalyst

“…The fabrication process is shown in Figure . As metal ions, including Co 2+ , Fe 3+ , and Ni 2+ , can catalyst NaTPB hydrolysis to release OH − slowly . With NaTPB in EG‐Wsolvent at 160 °C, the pH of the solution changed from weak acid (pH=6.0) to alkaline (pH=8.3) after two hours.…”

Degradation of triphenylborane–pyridine antifouling agent in water by copper ions

“…[1] Triphenylborane-pyridine (TPBP) is one of the alternative biocides and is used for ship antifouling paint in some Asian countries, including Japan. [4] Based on the literature, it was proposed that a series of reactions (1) and (2) could occur at the surface of antifouling coating containing TPBP and cuprous oxide; [2] however, no quantitative data accompanied the reactions: Amey and Waldron [2] mentioned in the Proceedings that TPBP was decomposed by hydrolysis, thermolysis, photolysis, and copper ions in aquatic environments, demonstrating the efficacy and chemistry of TPBP as an antifouling agent.…”