Polyphenylene-Based Solid Acid as an Efficient Catalyst for Activation and Hydration of Alkynes

Abstract

Porous polymer catalysts possess the potential to combine the advantages of heterogeneous and homogeneous catalysis, namely, easy postreaction recycling and high dispersion of active sites. Here, we designed a −SO 3 H functionalized polyphenylene (PPhen) framework with purely sp 2 -hybridized carbons, which exhibited high activity in the hydration of alkynes including challenging aliphatic substrates such as 1-octyne. The superiority of the structure lies in its covalent crosslink in the xyplane with a π−π stacking interaction between the planes, enabling simultaneously high swellability and porosity (653 m 2 •g −1 ). High acidic site density (2.12 mmol•g −1 ) was achieved under a mild sulfonation condition. Similar turnover frequencies (0.015 ± 0.001 min −1 ) were obtained regardless of acidic density and crosslink content, suggesting high accessibility for all active sites over PPhen. In addition, the substituted benzene groups can activate alkynes through a T-shape CH/π interaction, as indicated by the 8 and 16 cm −1 red shift of the alkyne C−H stretching peak for phenylacetylene and 1-octyne, respectively, in the infrared (IR) spectra. These advantages render PPhen-SO 3 H a promising candidate as a solid catalyst replacing the highly toxic liquid phase acids such as the mercury salt.

Heterogeneous Formic Acid Production by Hydrogenation of CO2 Catalyzed by Ir‐bpy Embedded in Polyphenylene Porous Organic Polymers

“…Recently, Wang et al. have shown that a sulfonated PP can hydrate alkyne bonds showing the versatility of such a material [20] . Yet, as the PP POP is made up exclusively of aromatic sp 2 ‐carbons in a ordered structure, it is very robust with inherent high porosity, and these features could make it ideal for applications in high‐pressure reactions like the hydrogenation of CO 2 to formate.…”

Design, Identification, and Evolution of a Surface Ruthenium(II/III) Single Site for CO Activation

“…The ratio is set to 1:3 for that raising the content of dibromo molecule will increase the linear content of the polymer, decrease the overall surface area and consequently reduce the accessibility to the bipy sites. [17] The PPhen-bipy is Pd free, as shown in the energy dispersive spectroscopy (EDS; Supporting Information, Figure S1).…”

“…The ratio between 5,5′‐dibromo‐2,2′‐bipyridine and 1,2,4,5‐tetrabromobenzene determines the amount of bipy ligands in relation to the PPhen‐bipy polymer, thereby the loading of single metal sites. The ratio is set to 1:3 for that raising the content of dibromo molecule will increase the linear content of the polymer, decrease the overall surface area and consequently reduce the accessibility to the bipy sites [17] . The PPhen‐bipy is Pd free, as shown in the energy dispersive spectroscopy (EDS; Supporting Information, Figure S1).…”

Rational design of bifunctional conjugated microporous polymers

“…Wang et al demonstrated a bifunctional acidic solid catalyst, PPhen-SO 3 H, which was obtained through the attachment of –SO 3 H groups to the polyphenylene (PPhen) framework via a post-synthetic modification. 126 PPhen-SO 3 H featuring high porosity and unique structure ensures the high accessibility of reactants to the active sites, representing enhanced activity in the hydration of alkynes with the combination of the solvation environments in the structure.…”