The silicalite-1 crystal with intracrystal pores in the range of 50–100 nm was synthesized by using the nanosized CaCO3 as a hard template. The nanosized CaCO3 can be trapped into the silicalite-1 crystal during the crystallization process. By means of acid dissolution, the encapsulated nanoparticles were removed, giving rise to the intracrystal pores within the zeolite crystal. Characterization techniques including XRD, TEM, SEM, and N2 adsorption provided the detailed information on this hierarchical pore structure. The hydroxyl groups on the surface of CaCO3 are essential to taking the hard template effect. The secondary pores within zeolite correspond well to the morphology of the nanosized CaCO3, which confirms the template effect of nanosized CaCO3. These results suggest that using CaCO3 as a hard template may be a useful approach for the synthesis of hierarchical porous materials.

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Many classical and emerging methodologies in organic chemistry rely on CO2 extrusion to generate reactive intermediates for bond-forming events. Synthetic reactions that involve the microscopic reverse, the carboxylation of reactive intermediates, have conventionally been undertaken using very different conditions. We report that chemically stable C(sp3) carboxylates, such as arylacetic acids and malonate half-esters, undergo uncatalyzed reversible decarboxylation in dimethylformamide solution. Decarboxylation/carboxylation occurs with substrates resistant to protodecarboxylation by Brønsted acids under otherwise identical conditions. Isotopically labeled carboxylic acids can be prepared in high chemical and isotopic yield by simply supplying an atmosphere of 13CO2 to carboxylate salts in polar aprotic solvents. An understanding of carboxylate reactivity in solution enables conditions for the trapping of aldehydes, ketones, and α,β-unsaturated esters.

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