Purifying ethylene with flexible zeolites: Ethylene is a key feedstock for many chemicals and polymers, but its production requires cryogenic separation from ethane, an energy-consuming step. In theory, pure silica zeolites are well suited to separate olefins from paraffins. Bereciartua et al. synthesized a pure silica zeolite with very small pores, which, if static, would not adsorb either of these hydrocarbons. However, molecular dynamics suggested that the pores should be flexible. Indeed, in competitive adsorption experiments, the zeolite preferentially adsorbed ethylene from a mixed stream of ethylene and ethane. Science , this issue p. 1068

A zeolite with microporous channels (6 to 7 angstrom diameter) and mesoporous channels (~2-nanometer diameter) was made.

Natural methane hydrates are believed to be the largest source of hydrocarbons on Earth. These structures are formed in specific locations such as deep-sea sediments and the permafrost based on demanding conditions of high pressure and low temperature. Here we report that, by taking advantage of the confinement effects on nanopore space, synthetic methane hydrates grow under mild conditions (3.5 MPa and 2 °C), with faster kinetics (within minutes) than nature, fully reversibly and with a nominal stoichiometry that mimics nature. The formation of the hydrate structures in nanospace and their similarity to natural hydrates is confirmed using inelastic neutron scattering experiments and synchrotron X-ray powder diffraction. These findings may be a step towards the application of a smart synthesis of methane hydrates in energy-demanding applications (for example, transportation).