Duan, Xiyan, et al. Tetrahedron Letters 142 (2024): 155105.
A novel method for the direct conversion of enaminones to α-keto amides has been developed, utilizing an oxidative rearrangement of enaminones under free radical conditions. In the presence of KI, TBHP and octanoic acid, a series of α-keto amides were obtained in moderate to excellent yields. This reaction shows excellent functional group compatibility, uses readily available materials, and is easy to perform. Furthermore, when o-hydroxyphenyl enaminone is used as the substrate, the reaction produces 3-iodochromone in high yield.
Hidajat, Marcel Jonathan, Gwang-Nam Yun, and Dong-Won Hwang. Molecular Catalysis 512 (2021): 111770.
Octanoic acid, a medium-chain fatty acid, can be produced through the aforementioned techniques or from the direct pyrolysis of waste plastics and wood chips. However, given the increasing demand for alternative fuel and chemical sources, the hydrogenation upgrade of octanoic acid is crucial as it can be transformed into more valuable chemicals such as octanol. Octanol has a wider range of applications, as it can be used in the production of fragrances, pharmaceuticals, detergents, lubricants, and emulsifiers, and also serves as an alternative to conventional transportation fuels.
Hydrogenation Process of Octanoic Acid
The gas-phase hydrogenation of octanoic acid is carried out in a fixed-bed continuous flow reactor using a bimetallic RuSn/ZnO catalyst. Reactive testing is conducted in a stainless steel continuous fixed-bed downflow reactor, which is 40 cm in length and 0.75 cm in diameter. A mesh element is installed inside the reactor to act as a catalyst filter. The reactor is equipped with a heating jacket capable of reaching up to 500 °C, controlled by a PID controller. Additionally, the reactor system is outfitted with an HPLC pump to control the liquid flow rate of octanoic acid entering the reactor and an MFC controller to manage the flow rate of H2. To ensure complete evaporation of octanoic acid before entering the reactor, the system features an evaporator and line heaters in the preheating zone, set to a temperature of 250 °C, thereby preventing condensation of octanoic acid pre-entry. The pressure within the reactor is regulated using a back-pressure regulator.
Zhang, Ke, et al. Food Hydrocolloids 152 (2024): 109914.
A multifunctional film was developed using gallic acid/octanoic acid-grafted chitosan (GA/OA-g-CS) to achieve high photodynamic antibacterial and antibiofilm efficacy under blue light (BL, 420 nm) illumination.
Synthesis of CS Conjugates
CS conjugates were synthesized through grafting reactions induced by AA/H₂O₂, based on previous reports with some modifications. Under an inert nitrogen atmosphere, 0.5 g of CS was dissolved in an acetic acid aqueous solution (10 mL, 2%, v/v). Then, H₂O₂ (1 mL, 5 M) containing AA (0.044 g) was added. Subsequently, one of GA, OA, or mixtures of GA and OA in different molar ratios (1:2, 1:1, 2:1) was added to the reaction vessel and the mixture was allowed to react overnight under a nitrogen atmosphere. The pH was adjusted to 7, and an excess of ethanol was added to precipitate the CS conjugates. The precipitate was collected and thoroughly washed with ethanol/water mixtures (increasing ethanol content from 70% to 100% v/v) to remove unreacted GA and OA. Finally, the precipitate was freeze-dried to yield the final products, designated as GA-g-CS, OA-g-CS, and GA/OA-g-CS.
Preparation of CS Conjugate Films
First, chitosan and the CS conjugates were dissolved in an acetic acid solution (2%, v/v) to prepare film-forming solutions (0.2%, w/v), which were stirred at room temperature overnight. The film-forming solutions were cast onto the surface of glass slides (22 mm × 22 mm) and dried in an oven at 50 °C for 3 hours to obtain the CS and CS conjugate films. Bare glass slides were used as controls. The hydrophobic chain of the GA/OA-g-CS (2:1) film was isolated in an α-CD (2 mL, 3%, w/v) hydrophobic cavity for 1 hour. The α-CD-treated surfaces were thoroughly washed with deionized water and dried overnight at 55 °C.
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