Naphthalene-Based Polymers as Catalytic Supports for Suzuki Cross-Coupling

In this work, for the first time, naphthalene (NA)-based polymers were synthesized by one-stage Friedel-Crafts crosslinking. The influence of NA functionalization by -OH, -SO₃H, and -NO₂ groups on the polymers' porosity and distribution of the catalytically active phase (Pd) was studied. Synthesized catalytic systems containing 1 wt.% of Pd either in the form of Pd(II) species or Pd(0) nanoparticles supported on NA-based polymers were tested in a model reaction of Suzuki cross-coupling between 4-bromoanisole and phenylboronic acid under mild reaction conditions (60 °C, ethanol-water mixture as a solvent). These novel catalysts demonstrated high efficiency with more than 95% of 4-bromoanisole conversion and high selectivity (>97%) for the target 4-methoxybiphenyl.

Adsorbents obtained from recycled polymeric materials for retention of different pollutants: A review

Polymeric waste is an environmental problem, with an annual world production of approximately 368 million metric tons, and increasing every year. Therefore, different strategies for polymer waste treatment have been developed, and the most common are (1) redesign, (2) reusing and (3) recycling. The latter strategy represents a useful option to generate new materials. This work reviews the emerging trends in the development of adsorbent materials obtained from polymer wastes. Adsorbents are used in filtration systems or in extraction techniques for the removal of contaminants such as heavy metals, dyes, polycyclic aromatic hydrocarbons and other organic compounds from air, biological and water samples. The methods used to obtain different adsorbents are detailed, as well as the interaction mechanisms with the compounds of interest (contaminants). The adsorbents obtained are an alternative to recycle polymeric and they are competitive with other materials applied in the removal and extraction of contaminants.

Role of sulfonation in the stability, reactivity, and selectivity of poly(ether imide) used to develop ion exchange membranes: DFT study with application to fuel cells

The design of polymer electrolyte membranes for fuel cells must satisfy two equally important fundamental principles: optimization of the reactivity and the selectivity in order to improve the ion transport properties of the membrane as well as its long-term stability in the hydrated state at high temperature (above 100 °C). A study utilizing density functional theory (DFT) to elucidate the effect of the degree of sulfonation on the chemical stability, reactivity, and selectivity of poly(ether imide) (PEI), which allows the ionic transport properties of the membrane to be predicted, is reported here. Sulfonated poly(ether imide) (SPEI) structures with (-SO3H) n (n = 1-6) groups were built and optimized in order to calculate the above properties as functions of the number of sulfonyl groups. A comparative study demonstrated that the SPEI with four sulfonyl groups in its backbone is the polymer with the properties best suited for use in fuel cells.