Hierarchical Sn-Beta was prepared by a hydrothermal postsynthesis method. It shows higher catalytic activity for conversion of glucose to alkyl lactate than microporous Sn-Beta hydrothermally synthesized in fluoride media.

Transition-metal-catalyzed transfer hydrogenation with an in situ hydrogen donor has received a great deal of attention from both academia and industry as an alternative to the traditional high-pressure-hydrogen process, owing to its better efficiency, atom economy, and sustainability features. Hydrogen stored in the chemical bonds of formic acid (FA), a promising hydrogen storage compound that could be derived from biomass or reduction of CO2, can be extracted selectively and used for diverse catalytic transformations. This Review summarizes and compares recent progress in catalytic transfer hydrogenation (CTH) via heterogeneous hydrogen transfer from FA. Transformations of biomass-derived platform chemicals (e.g., aromatic units, C5 and C6 sugars, furans, glycerol, fatty acids, levulinic acid (LA)), nitrogen-containing compounds (e.g., nitroarenes, quinolines), and organochlorinated compounds via transfer hydrogenation, hydrogenolysis, and hydrodechlorination (HDC) are outlined. Synthesis strategies of the heterogeneous metal catalysts (e.g., metal and support type, metal–support interaction, single-atom, alloy effect, and confinement effect) and optimization of the reaction conditions (e.g., temperature, solvents, additives, and FA dosages) for enhancing the catalytic activity and regulating the product distribution are presented. Structure–activity relationships based on both dehydrogenation and hydrogenation of metal catalysts as well as the mechanistic interpretation of CTH with FA are also highlighted. Finally, current challenges and outlook for the future development of the field are discussed.

SummaryThe base‐editing technique using CRISPR/nCas9 (Cas9 nickase) or dCas9 (deactivated Cas9) fused with cytidine deaminase is a powerful tool to create point mutations. In this study, a novel G. hirsutum‐Base Editor 3 (GhBE3) base‐editing system has been developed to create single‐base mutations in the allotetraploid genome of cotton (Gossypium hirsutum). A cytidine deaminase sequence (APOBEC) fused with nCas9 and uracil glycosylase inhibitor (UGI) was inserted into our CRISPR/Cas9 plasmid (pRGEB32‐GhU6.7). Three target sites were chosen for two target genes, GhCLA and GhPEBP, to test the efficiency and accuracy of GhBE3. The editing efficiency ranged from 26.67 to 57.78% at the three target sites. Targeted deep sequencing revealed that the C→T substitution efficiency within an ‘editing window’, approximately six‐nucleotide windows of −17 to −12 bp from the PAM sequence, was up to 18.63% of the total sequences. The 27 most likely off‐target sites predicted by CRISPR‐P and Cas‐OFFinder tools were analysed by targeted deep sequencing, and it was found that rare C→T substitutions (average < 0.1%) were detected in the editing windows of these sites. Furthermore, whole‐genome sequencing analyses on two GhCLA‐edited and one wild‐type plants with about 100× depth showed that no bona fide off‐target mutations were detectable from 1500 predicted potential off‐target sites across the genome. In addition, the edited bases were inherited to T1 progeny. These results demonstrate that GhBE3 has high specificity and accuracy for the generation of targeted point mutations in allotetraploid cotton.

Rapid synthesis of Sn-containing nanosized all-silica Beta zeolite was developed in this work. The method employed all-silica Beta (Si-Beta) as parent, which was crystallized in several hours by the hydrothermal method, and incorporated Sn to Si-Beta through grinding with SnCl4·5H2O and subsequent calcination procedure. The prepared Sn-Beta zeolites were analyzed by several methods including XRD, SEM, N2 physisorption, FT-IR spectroscopy of deuterated acetonitrile and pyridine adsorption, UV–vis DR, and XPS. The mechanism of incorporation of Sn sites into the framework of zeolite was revealed. The results show that the successful incorporation of Sn sites strongly depends on the crystallinity of the parent Si-Beta. Si-Beta with lower crystallinity (<90%) had a considerable amount of silanols which provided sites for Sn incorporation into the framework sites. For Si-Beta with higher crystallinity and less silanols, desilication was used to generate more silanols for the incorporation of Sn sites. The prepared Sn-Beta zeolites were effective for the transformation of glucose to methyl lactate (MLA). Its catalytic activity is better than those of Sn-Beta-P prepared by dealumination–stannation of Al-Beta and Sn-Beta-F synthesized through the traditional hydrothermal method. Turnover frequency (TOF) was calculated on the amount of framework Sn sites to measure the intrinsic and initial activity of active Sn sites. TOF values varied in the sequence of nano Sn-Beta ≫ Sn-Beta-F ≫ Sn-Beta-P. The high MLA yield for nano Sn-Beta is due to its higher mesoporosity. The prepared Sn-Beta zeolite was recycled eight times in the transformation of glucose to MLA without any decrease of catalytic activity. Additionally, the effect of potassium salt on the formation of MLA from glucose over Sn-Beta catalyst was studied.

Mg-Sn-Beta zeolites with different Mg/Sn molar ratios were prepared from the parent deAl-Beta by a coimpregnation method. It shows higher selectivity for the conversion of glucose to methyl lactate than post-synthesized Sn-Beta.