Design of an Organic Template for Synthesizing ITR Zeolites under Ge-Free Conditions.

Germanosilicate zeolites with various structures have been extensively synthesized, but the syntheses of corresponding zeolite structures in the absence of germanium species remain a challenge. One such example is an ITR zeolite structure, which is a twin of the ITH zeolite structure. Through the modification of a classic organic template for synthesizing ITH zeolites and thus designing a new organic template with high compatibility to ITR zeolite assisted by theoretical simulation, we, for the first time, show the Ge-free synthesis of an ITR structure including pure silica, aluminosilicate, and borosilicate ITR zeolites. These materials have high crystallinity, corresponding to an ITR content of more than 95%. In the methanol-to-propylene (MTP) reaction, the obtained aluminosilicate ITR zeolite exhibits excellent propylene selectivity and a long lifetime compared with conventional aluminosilicate ZSM-5 zeolite. The strategy for the design of organic templates might offer a new opportunity for rational syntheses of novel zeolites and, thus, the development of highly efficient zeolite catalysts in the future.

Low-silica Cu-CHA Zeolite Enriched with Al Pairs Transcribed from Silicoaluminophosphate Seed: Synthesis and Ammonia Selective Catalytic Reduction Performance.

Cu-exchanged low-silica CHA zeolites (Si/Al≤4) synthesized without organic templates are promising candidate catalysts for ammonia selective catalytic reduction of nitrogen oxides (NH3 -SCR), but their practical application is restricted due to the low hydrothermal stability. Here, inspired by the transcription from duplex DNA to RNA, we synthesized Al pairs enriched low-silica CHA zeolite (CHA-SPAEI, Si/Al=3.7) by using silicoaluminophosphate (SAPO) featured by strict alternation of -Al-O-P(Si)-O-Al-O- tetrahedra as seed. The proportion of Al pairs in CHA-SPAEI is 78 %, which is much higher than that in the conventional low-silica CHA (CHA-LS, 52 %). After hydrothermal ageing at 800 °C for 6 h, Cu-exchanged CHA-SPAEI shows NO conversion above 90 % within 225-500 °C under a gas hourly space velocity of 200,000 h-1 , which is much better than that of Cu-exchanged CHA-LS. The spatial close proximity of Al pairs in CHA-SPAEI is confirmed by the 27 Al double-quantum single-quantum two-dimensional NMR analyses. The strict -P(Si)-O-Al-O-P(Si)-O- sequence in the fragments from the dissolution of SAPO seed promotes the Al pairs with the -Al-O-Si-O-Al-O- sequence via a transcription process. The utilization of aluminophosphate-based zeolites as seeds opens up a new avenue for the regulation of the Al distribution in zeolites.

Porous Supramolecular Assemblies for Efficient Suzuki Coupling of Aryl Chlorides.

The development of catalytic systems that can activate aryl chlorides for palladium-catalyzed cross-coupling reactions is at the forefront of ongoing efforts to synthesize fine chemicals. In this study, a facile ligand-template approach is adopted to achieve active-site encapsulation by forming supramolecular assemblies; this bestowed the pristine inert counterparts with reactivity, which is further increased upon the construction of a porous framework. Experimental results indicated that the isolation of ligands by the surrounding template units is key to the formation of catalytically active monoligated palladium complexes. Additionally, the construction of porous frameworks using the resulting supramolecular assemblies prevented the decomposition of the Pd complexes into nanoparticles, which drastically increased the catalyst lifetime. These findings, along with the simplicity and generality of the synthesis scheme, suggest that the strategy can be leveraged to achieve unique reactivity and potentially enable fine-chemical synthesis.

Influence of Perioperative COVID-19 Infection on Surgical Outcomes and Risk Adjustment for Quality Assessment in the American College of Surgeons NSQIP.

BACKGROUND: Surgical patients with perioperative coronavirus disease 19 (COVID-19) infection experience higher rates of adverse events than those without COVID-19, which may lead to imprecision in hospital-level quality assessment. Our objectives were to quantify differences in COVID-19-associated adverse events in a large national sample and examine distortions in surgical quality benchmarking if COVID-19 status is not considered. STUDY DESIGN: Data included 793,280 patient records from the American College of Surgeons NSQIP from April 1, 2020, to March 31, 2021. Models predicting 30-day mortality, morbidity, pneumonia, and ventilator dependency greater than 48 hours, and unplanned intubation were constructed. Risk adjustment variables were selected for these models from standard NSQIP predictors and perioperative COVID-19 status. RESULTS: A total of 5,878 (0.66%) had preoperative COVID-19, and 5,215 (0.58%) had postoperative COVID-19. COVID-19 rates demonstrated some consistency across hospitals (median preoperative 0.84%, interquartile range 0.14% to 0.84%; median postoperative 0.50%, interquartile range 0.24% to 0.78%). Postoperative COVID-19 was always associated with increased adverse events. For postoperative COVID-19 among all cases, there was nearly a 6-fold increase in mortality (1.07% to 6.37%) and15-fold increase in pneumonia (0.92% to 13.57%), excluding the diagnosis of COVID-19 itself. The effects of preoperative COVID-19 were less consistent. Inclusion of COVID-19 in risk-adjustment models had minimal effects on surgical quality assessments. CONCLUSIONS: Perioperative COVID-19 was associated with a dramatic increase in adverse events. However, quality benchmarking was minimally affected. This may be the result of low overall COVID-19 rates or balance in rates established across hospitals during the 1-year observational period. There remains limited evidence for restructuring ACS NSQIP risk-adjustment for the time-limited effects of the COVID-19 pandemic.

A Six-Membered Ring Molecular Sieve Achieved by a Reconstruction Route.

Zeolite molecular sieves with at least eight-membered rings are widely applied in industrial applications, while zeolite crystals with six-membered rings are normally regarded as useless products due to the occupancy of the organic templates and/or inorganic cation in the micropores that could not be removed. Herein, we showed that a novel six-membered ring molecular sieve (ZJM-9) with fully open micropores could be achieved by a reconstruction route. The mixed gas breakthrough experiments such as CH3OH/H2O, CH4/H2O, CO2/H2O, and CO/H2O at 25 °C showed that this molecular sieve was efficient for selective dehydration. Particularly, a lower desorption temperature (95 °C) of ZJM-9 than that (250 °C) of the commercial 3A molecular sieve might offer an opportunity for saving more energy in dehydration processes.

Advances in emission control of diesel vehicles in China.

Diesel vehicles have caused serious environmental problems in China. Hence, the Chinese government has launched serious actions against air pollution and imposed more stringent regulations on diesel vehicle emissions in the latest China VI standard. To fulfill this stringent legislation, two major technical routes, including the exhaust gas recirculation (EGR) and high-efficiency selective catalytic reduction (SCR) routes, have been developed for diesel engines. Moreover, complicated aftertreatment technologies have also been developed, including use of a diesel oxidation catalyst (DOC) for controlling carbon monoxide (CO) and hydrocarbon (HC) emissions, diesel particulate filter (DPF) for particle mass (PM) emission control, SCR for the control of NOx emission, and an ammonia slip catalyst (ASC) for the control of unreacted NH3. Due to the stringent requirements of the China VI standard, the aftertreatment system needs to be more deeply integrated with the engine system. In the future, aftertreatment technologies will need further upgrades to fulfill the requirements of the near-zero emission target for diesel vehicles.

Stable Porous Organic Polymers Used for Reversible Adsorption and Efficient Separation of Trace SO2.

The development of porous solid adsorbents for selective adsorption and separation of SO2 has attracted much attention recently. Herein, we design porous organic polymers (POPs) decorated with pyridine ligands as building units (POP-Py) through a radical polymerization of the 2,5-divinylpyridine (v-Py) monomer. Due to its high BET surface area, nanoporosity, and excellent stability, the prepared POP-Py can be used for reversible adsorption and efficient separation of SO2. The POP-Py possesses a SO2 capacity of 10.8 mmol g-1 at 298 K and 1.0 bar, which can be well retained after 6 recycles, showing an excellent reversible adsorption capacity. The POP-Py also shows superior separation performance for SO2 from a ternary SO2/CO2/N2 mixture (0.17/15/84.83v%), giving a breakthrough time and a saturated SO2 capacity at 178 min g-1 and 0.4 mmol g-1. The retention time was well maintained even under high moisture conditions, confirming its superior water resistance. Furthermore, when other vinyl-functionalized organic ligand monomers (bipyridine, pyrimidine, and pyrazine) were employed for radical polymerization, all of the resultant porous organic ligand polymers (POP-BPy, POP-PyI, and POP-PyA) exhibited superior performance for reversible adsorption and efficient separation of SO2. The combined features of reversible adsorption, efficient separation, and water resistance are important for the industrial applications of these materials as SO2 adsorbents.

Design of a Small Organic Template for the Synthesis of Self-Pillared Pentasil Zeolite Nanosheets.

Zeolite nanosheets with excellent mass transfer are attractive, but their successful syntheses are normally resulted from a huge number of experiments. Here, we show the design of a small organic template for the synthesis of self-pillared pentasil (SPP) zeolite nanosheets from theoretical calculations in interaction energies between organic templates and pentasil zeolite skeletons. As expected, the SPP zeolite nanosheets with the thickness at 10-20 nm have been synthesized successfully. Characterizations show that the SPP zeolite nanosheets with about 90% MFI and 10% MEL structures have good crystallinity, the house-of-card morphology, large surface area, and fully four-coordinated aluminum species. More importantly, methanol-to-propylene tests show that the SPP zeolite nanosheets exhibit much higher propylene selectivity and longer reaction lifetime than conventional ZSM-5 zeolite. These results offer a good opportunity to develop highly efficient zeolite catalysts in the future.

Selective catalytic reduction of NO x with NH3: opportunities and challenges of Cu-based small-pore zeolites.

Zeolites, as efficient and stable catalysts, are widely used in the environmental catalysis field. Typically, Cu-SSZ-13 with small-pore structure shows excellent catalytic activity for selective catalytic reduction of NO x with ammonia (NH3-SCR) as well as high hydrothermal stability. This review summarizes major advances in Cu-SSZ-13 applied to the NH3-SCR reaction, including the state of copper species, standard and fast SCR reaction mechanism, hydrothermal deactivation mechanism, poisoning resistance and synthetic methodology. The review gives a valuable summary of new insights into the matching between SCR catalyst design principles and the characteristics of Cu2+-exchanged zeolitic catalysts, highlighting the significant opportunity presented by zeolite-based catalysts. Principles for designing zeolites with excellent NH3-SCR performance and hydrothermal stability are proposed. On the basis of these principles, more hydrothermally stable Cu-AEI and Cu-LTA zeolites are elaborated as well as other alternative zeolites applied to NH3-SCR. Finally, we call attention to the challenges facing Cu-based small-pore zeolites that still need to be addressed.

Microwave-Assisted Defibrillation of Microalgae.

The first production of defibrillated celluloses from microalgal biomass using acid-free, TEMPO-free and bleach-free hydrothermal microwave processing is reported. Two routes were explored: i. direct microwave process of native microalgae ("standard"), and ii. scCO2 pre-treatment followed by microwave processing. ScCO2 was investigated as it is commonly used to extract lipids and generates considerable quantities of spent algal biomass. Defibrillation was evidenced in both cases to afford cellulosic strands, which progressively decreased in their width and length as the microwave processing temperature increased from 160 °C to 220 °C. Lower temperatures revealed aspect ratios similar to microfibrillated cellulose whilst at the highest temperature (220 °C), a mixture of microfibrillated cellulose and nanocrystals were evidenced. XRD studies showed similar patterns to cellulose I but also some unresolved peaks. The crystallinity index (CrI), determined by XRD, increased with increasing microwave processing temperature. The water holding capacity (WHC) of all materials was approximately 4.5 g H2O/g sample. The materials were able to form partially stable hydrogels, but only with those processed above 200 °C and at a concentration of 3 wt% in water. This unique work provides a new set of materials with potential applications in the packaging, food, pharmaceutical and cosmetic industries.

Metalated Porous Phenanthroline-Based Polymers as Efficient Heterogeneous Catalysts for Regioselective C-H Activation of Heteroarenes.

Direct C-H bond activation of heterocycles as a step-economical and environmentally friendly approach to build the heterobiaryls motifs is highly attractive, but it still has a challenge to design and prepare a cheap and regioselective heterogeneous catalyst. To tackle this challenge, we have introduced Ni species into a porous phenanthroline-based organic polymer donated as POP-Phen@Ni. This heterogeneous catalyst shows excellent catalytic performances in regioselective C-H activation of heterocycles, even better than those of the corresponding homogenous catalyst. H/D exchange experiments show that the lithium bis(trimethylsilyl)amide (LiHMDS), a base added in the reaction, play a very important role during the reaction processes. We believe that this heterogeneous catalyst would open a new door for design of heterogeneous catalysts to efficiently catalyze the regioselective C-H activation of heterocycles.

Isolated boron in zeolite for oxidative dehydrogenation of propane.

Oxidative dehydrogenation of propane (ODHP) is a key technology for producing propene from shale gas, but conventional metal oxide catalysts are prone to overoxidation to form valueless CO x Boron-based catalysts were recently found to be selective for this reaction, and B-O-B oligomers are generally regarded as active centers. We show here that the isolated boron in a zeolite framework without such oligomers exhibits high activity and selectivity for ODHP, which also hinders full hydrolysis for boron leaching in a humid atmosphere because of the B-O-SiO x linkage, achieving superior durability in a long-period test. Furthermore, we demonstrate an isolated boron with a -B[OH…O(H)-Si]2 structure in borosilicate zeolite as the active center, which enables the activation of oxygen and a carbon-hydrogen bond to catalyze the ODHP.

Porous Organic Phenanthroline-Based Polymer as an Efficient Transition-Metal-Free Heterogeneous Catalyst for Direct Aromatic C-H Activation.

Direct C-H bond transformation has been regarded as one of the most important areas in organic synthesis in both academia and industry. However, the heterogeneous transition-metal-free catalysis of direct C-H bond transformation has remained a contemporary challenge. To tackle this challenge, we designed and constructed a porous phenanthroline-based polymer (namely POP-Phen) via free radical polymerization of vinyl-functionalized phenanthroline monomers. POP-Phen shows excellent catalytic performances in transition-metal-free catalyzed C-H arylation, even better than those of the corresponding homogeneous catalyst, which is mainly attributed to the high density of catalytically active sites in the heterogeneous catalyst. Kinetic isotope experiments and spectral characterizations demonstrate the electron-transfer between the heterogeneous catalyst and the base (t-BuOK), a key step for C-H activation. We believe that this porous organic phenanthroline polymer could open a new door for the design of novel heterogeneous transition-metal-free catalysts for direct C-H activation.

Coking-Resistant Iron Catalyst in Ethane Dehydrogenation Achieved through Siliceous Zeolite Modulation.

Nonoxidative dehydrogenation is promising for production of light olefins from shale gas, but current technology relies on precious Pt or toxic Cr catalysts and suffers from thermodynamically oriented coke formation. To solve these issues, the earth-abundant iron catalyst is employed, where Fe species are effectively modulated by siliceous zeolite, which is realized by the synthesis of Fe-containing MFI siliceous zeolite in the presence of ethylenediaminetetraacetic sodium (FeS-1-EDTA). Catalytic tests in ethane dehydrogenation show that this catalyst has a superior coke resistance in a 200 h run without any deactivation with extremely high activity and selectivity (e.g., 26.3% conversion and over 97.5% selectivity to ethene in at 873 K, close to the thermodynamic equilibrium limitation). Multiple characterizations demonstrate that the catalyst has uniformly and stably isolated Fe sites, which improves ethane dehydrogenation to facilitate the fast desorption of hydrogen and olefin products in the zeolite micropores and hinders the coke formation, as also identified by density functional calculations.

Synthesis of Aluminophosphate Molecular Sieves in Alkaline Media.

Unlike conventional aluminosilicate zeolites synthesized in alkaline media, aluminophosphate molecular sieves (AlPOs) have always been prepared under acidic conditions in the past three decades; this has been regarded as one of essential factors for synthesis, except for the case of silica-substituted analogues (SAPOs). For the first time, we demonstrate herein a simple and generalized route for synthesizing various types of aluminophosphate molecular sieves in alkaline media. A series of aluminophosphate sieves and their analogues have been prepared with different quaternary ammonium cations as structure-directing agents in this manner. The above successes have extended the systematic media from acidic or neutral to alkaline for the preparation of a series of aluminophosphate molecular sieves, which possibly open an alternative route for the synthesis of aluminophosphate molecular sieves.

A Cationic Oligomer as an Organic Template for Direct Synthesis of Aluminosilicate ITH Zeolite.

There are a large number of zeolites, such as ITH, that cannot be prepared in the aluminosilicate form. Now, the successful synthesis of aluminosilicate ITH zeolite using a simple cationic oligomer as an organic template is presented. Key to the success is that the cationic oligomer has a strong complexation ability with aluminum species combined with a structural directing ability for the ITH structure similar to that of the conventional organic template. The aluminosilicate ITH zeolite has very high crystallinity, nanosheet-like crystal morphology, large surface area, fully four-coordinated Al species, and abundant acidic sites. Methanol-to-propylene (MTP) tests reveal that the Al-ITH zeolite shows much higher selectivity for propylene and longer lifetime than commercial ZSM-5. FCC tests show that Al-ITH zeolite is a good candidate as a shape-selective FCC additive for enhancing propylene and butylene selectivity.

Author Correction: Silica accelerates the selective hydrogenation of CO2 to methanol on cobalt catalysts.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Illuminating solvent-free synthesis of zeolites.

With the merits of the accelerated crystallization process, high volume yields, and reduced waste production, solvent-free syntheses give new opportunities for the fabrication of zeolites. In this Frontier, a background overview is provided, consisting of a brief introduction of challenges in traditional zeolite syntheses and how solvent-free syntheses provide the right combination of properties for achieving a more sustainable route. Next, recent advancements in zeolites synthesized under solvent-free conditions are exemplified along with discussions about the strategies and principles involved. Finally, the remaining challenges and opportunities for this synthetic route are outlined.

Does Comanagement of Patients With Hip Fracture Influence 30-Day Outcomes.

INTRODUCTION: Comanagement of hip fractures is thought to optimize outcomes for these high-risk patients, but this practice is not universal. We aimed to determine whether comanagement of patients with hip fracture affects 30-day outcomes. METHODS: The American College of Surgeons National Surgical Quality Improvement Program database was queried for all hip fractures between January 2015 and January 2017, totaling 15 461 patients (144 hospitals). Patients were divided into 3 cohorts: 11 233 comanaged throughout stay (CM), 2537 partially comanaged during stay (PCM), or 1691 not comanaged (NCM), by orthopedic surgeons with medicine physicians or geriatricians. Data collected included demographics, hip fracture type, postoperative outcomes, and length of stay (LOS). Logistic regression and linear regression analyses were performed. RESULTS: Both CM and PCM patients were older, with more dementia, poorer mobility, and more comorbidities than NCM patients. Mortality rates were 4.55%, 0.81%, and 0.33% for CM, PCM, and NCM, respectively, and risk-adjusted odds ratios (ORs) were 1.63 (95% confidence interval = 1.22-2.23) and 1.22 (0.87-1.74) for CM and PCM, respectively, compared to NCM. Morbidity rates were 11.06%, 15.45%, and 7.63% for CM, PCM, and NCM, respectively, and ORs were 1.74 (1.41-2.16) and 1.94 (1.57-2.41) for CM and PCM, respectively, compared to NCM. Risk-adjusted mean square LOS was 6.38, 8.80, and 7.23 for CM, PCM, and NC, respectively (P < .01). CONCLUSIONS: Comanaged patients with hip fracture had poorer cognition, function, and general health, with the shortest LOS. Surprisingly, NCM was associated with reduced morbidity and mortality, which may relate to them being the healthiest patients. Overall, our findings still support orthogeriatric comanagement in this high-risk group to maximize outcomes.

Silica accelerates the selective hydrogenation of CO2 to methanol on cobalt catalysts.

The reaction pathways on supported catalysts can be tuned by optimizing the catalyst structures, which helps the development of efficient catalysts. Such design is particularly desired for CO2 hydrogenation, which is characterized by complex pathways and multiple products. Here, we report an investigation of supported cobalt, which is known for its hydrocarbon production and ability to turn into a selective catalyst for methanol synthesis in CO2 hydrogenation which exhibits good activity and stability. The crucial technique is to use the silica, acting as a support and ligand, to modify the cobalt species via Co‒O‒SiOn linkages, which favor the reactivity of spectroscopically identified *CH3O intermediates, that more readily undergo hydrogenation to methanol than the C‒O dissociation associated with hydrocarbon formation. Cobalt catalysts in this class offer appealing opportunities for optimizing selectivity in CO2 hydrogenation and producing high-grade methanol. By identifying this function of silica, we provide support for rationally controlling these reaction pathways.