Accelerating ASEAN's energy transition in the power sector through cross-border transmission and a net-zero 2050 view.

Faced with energy transition objectives, the ten countries of the Association of Southeast Asian Nations (ASEAN) have technology options to decarbonize power sector. This study investigates the hypothetical decarbonization pathways for ASEAN's power sector. Here, we present an integrated power system capacity expansion model for ASEAN over 2018-2050.

Covalent organic frameworks for CO capture: from laboratory curiosity to industry implementation.

CO concentration in the atmosphere has increased by about 40% since the 1960s. Among various technologies available for carbon capture, adsorption and membrane processes have been receiving tremendous attention due to their potential to capture CO at low costs. The kernel for such processes is the sorbent and membrane materials, and tremendous progress has been made in designing and fabricating novel porous materials for carbon capture.

Functionalization of zeolite ZSM-5 by hydrosilylation and acetone coupling: synthesis, MAS NMR, and theory.

We report a two-step postsynthetic functionalization reaction of zeolite HZSM-5 that proceeds with high selectivity at room temperature. In the first step the framework acid sites of the zeolite are reacted with phenylsilane to replace the acidic proton with a hydrosilyl (-SiH3) group covalently linked to the framework. This group readily couples to acetone in a second step to form a framework-bound hydrosilyl isopropyl ether that is thermally stable at 473 K, but decomposes in the presence of moisture.

Structural and mechanistic investigation of a phosphate-modified HZSM-5 catalyst for methanol conversion.

Phosphorus modification of a HZSM-5 (MFI) zeolite by wet impregnation has long been known to decrease aromatic formation in methanol conversion chemistry. We prepared and studied a catalyst modified by introducing trimethylphosphine under reaction conditions followed by oxidation. Magic-angle spinning (MAS) NMR shows that extensive dealumination occurs, resulting in a catalyst with a much higher framework SiO2/Al2O3 ratio, as well as extraframework aluminum and approximately 1.

Reactions of halobenzenes with methanol on the microporous solid acids hbeta, HZSM-5, and HSAPO-5: halogenation does not improve the hydrocarbon pool.

The reactions of fluorobenzene, 3-fluorotoluene, and three isomers of difluorotoluene, chlorobenzene, and bromobenzene with excesses of methanol were investigated on the large-pore catalysts HBeta (*BEA) and HSAPO-5 (AFI), and on the medium-pore HZSM-5 (MFI). Flow reactor studies in pulse mode with GC-MS detection revealed that the fluorobenzene derivatives were readily methylated at, for example, 375 degrees C, but not even pentamethylfluorobenzene was obviously active as a reaction center for methanol-to-olefin (MTO) catalysis. Carbon-labeling studies revealed that small amounts of methylbenzenes were formed by defluorination, and these aromatic hydrocarbons seemed to account for the small yields of olefins (and their secondary reaction products) observed.

Trimethylsilylation of framework Brønsted acid sites in microporous zeolites and silico-aluminophosphates.

Framework-bound alkoxy groups are well-studied intermediates in zeolite chemistry, but their low stability complicates their spectroscopic study in high-temperature reactions such as alkylation or dealkylation. Taking advantage of the much higher bond strength of Si-O versus C-O, we synthesized trimethylsilylated zeolites by reacting them with phenyltrimethylsilane in a catalytic flow reactor at 648 K. In favorable cases, the reaction accurately titrated the acid sites, and 29Si and 13C MAS NMR spectra of the derivatized catalysts measured at room temperature confirmed the proposed reaction.