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Open AccessArticle

Carbonylation of Polyfluorinated Alkylbenzenes and Benzocycloalkenes at the Benzyl C-F and C-Cl Bonds Under the Action of CO/SbF₅

by Yaroslav V. Zonov, Siqi Wang, Vladislav V. Komarov, Victor M. Karpov, Dmitriy A. Parkhomenko and Tatyana V. Mezhenkova

Molecules 2025, 30(4), 931; https://doi.org/10.3390/molecules30040931 - 17 Feb 2025

Cited by 1 | Viewed by 1643

Abstract

The carbonylation at the benzyl C-Hal bonds (Hal = F, Cl) of a number of polyfluorinated alkylbenzenes and benzocycloalkenes using carbon monoxide in the presence of SbF₅ is described. The reaction provided the corresponding α-arylcarboxylic acids or their methyl esters following aqueous or methanol treatment. The products of double carbonylation were obtained from bis(chloromethyl)tetrafluorobenzenes and benzal fluorides. For benzal chloride derivatives, the possibility of selective mono- or dicarbonylation was shown to depend on the amount of antimony pentafluoride. In the case of polyfluorinated secondary benzyl halides with a hydrogen atom at the α-carbon atom and vicinal fluorine atoms, the addition of CO was found to be accompanied by the elimination of HF, resulting in α,β-unsaturated α-arylcarboxylic acids. The double elimination of HF during the carbonylation of 1,4-dichloro-2,2,3,3,5,6,7,8-octafluorotetralin yielded dimethyl perfluoronaphthalene-1,4-dicarboxylate. Full article

(This article belongs to the Section Organic Chemistry)

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13 pages, 7061 KB

Open AccessArticle

Significant Electromechanical Characteristic Enhancement of Coaxial Electrospinning Core–Shell Fibers

by Duc-Nam Nguyen and Wonkyu Moon

Polymers 2022, 14(9), 1739; https://doi.org/10.3390/polym14091739 - 25 Apr 2022

Cited by 15 | Viewed by 4049

Abstract

Electrospinning is a low-cost and straightforward method for producing various types of polymers in micro/nanofiber form. Among the various types of polymers, electrospun piezoelectric polymers have many potential applications. In this study, a new type of functional microfiber composed of poly(γ-benzyl-α,L-glutamate) (PBLG) and poly(vinylidene fluoride) (PVDF) with significantly enhanced electromechanical properties has been reported. Recently reported electrospun PBLG fibers exhibit polarity along the axial direction, while electrospun PVDF fibers have the highest net dipole moment in the transverse direction. Hence, a combination of PBLG and PVDF as a core–shell structure has been investigated in the present work. On polarization under a high voltage, enhancement in the net dipole moment in each material and the intramolecular conformation was observed. The piezoelectric coefficient of the electrospun PBLG/PVDF core–shell fibers was measured to be up to 68 pC N⁻¹ (d₃₃), and the voltage generation under longitudinal extension was 400 mVpp (peak-to-peak) at a frequency of 60 Hz, which is better than that of the electrospun homopolymer fibers. Such new types of functional materials can be used in various applications, such as sensors, actuators, smart materials, implantable biosensors, biomedical engineering devices, and energy harvesting devices. Full article

(This article belongs to the Special Issue Polymer-Based Materials for Sensors)

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13 pages, 7356 KB

Open AccessEditor’s ChoiceReview

Advances on Polymer Optical Fiber Gratings Using a KrF Pulsed Laser System Operating at 248 nm

by Carlos A. F. Marques, Arnaldo G. Leal-Junior, Rui Min, Maria Domingues, Cátia Leitão, Paulo Antunes, Beatriz Ortega and Paulo André

Fibers 2018, 6(1), 13; https://doi.org/10.3390/fib6010013 - 1 Mar 2018

Cited by 73 | Viewed by 7390

Abstract

This paper presents the achievements and progress made on the polymer optical fiber (POF) gratings inscription in different types of Fiber Bragg Gratings (FBGs) and long period gratings (LPGs). Since the first demonstration of POFBGs in 1999, significant progress has been made where the inscription times that were higher than 1 h have been reduced to 15 ns with the application of the krypton fluoride (KrF) pulsed laser operating at 248 nm and thermal treatments such as the pre-annealing of fibers. In addition, the application of dopants such as benzyl dimethyl ketal (BDK) has provided a significant decrease of the fiber inscription time. Furthermore, such improvements lead to the possibility of inscribing POF gratings in 850 nm and 600 nm, instead of only the 1550 nm region. The progress on the inscription of different types of polymer optical fiber Bragg gratings (POFBGs) such as chirped POFBGs and phase-shifted POFBGs are also reported in this review. Full article

(This article belongs to the Special Issue Optical Fiber Communications)

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