Deciphering Local Structural Complexity in Zn/Ga-ZrO2 CO2 Hydrogenation Catalysts.

In the last few decades, massive effort has been expended in heterogeneous catalysis to develop new materials presenting high conversion, selectivity, and stability even under high-temperature and high-pressure conditions. In this context, CO2 hydrogenation is an interesting reaction where the catalyst local structure is strongly related to the development of an active and stable material under hydrothermal conditions at T/P > 300 °C/30 bar. In order to clarify the relationship between catalyst local ordering and its activity/stability, we herein report a combined laboratory and synchrotron investigation of aliovalent element (Ce/Zn/Ga)-containing ZrO2 matrixes. The results reveal the influence of similar average structures with different short-range orderings on the catalyst properties. Moreover, a further step toward the comprehension of the oxygen vacancy formation mechanism in Ce- and Ga-ZrO2 catalysts is reported. Finally, the reported results illustrate a robust method to guide local structure determination and ultimately help to avoid overuse of the "solid solution" definition.

Regioselective hydroformylation of propene catalysed by rhodium-zeolite.

Hydroformylation is an industrial process for the production of aldehydes from alkenes1,2. Regioselective hydroformylation of propene to high-value n-butanal is particularly important, owing to a wide range of bulk applications of n-butanal in the manufacture of various necessities in human daily life3. Supported rhodium (Rh) hydroformylation catalysts, which often excel in catalyst recyclability, ease of separation and adaptability for continuous-flow processes, have been greatly exploited4. Nonetheless, they usually consist of rotationally flexible and sterically unconstrained Rh hydride dicarbonyl centres, only affording limited regioselectivity to n-butanal5-8. Here we show that proper encapsulation of Rh species comprising Rh(I)-gem-dicarbonyl centres within a MEL zeolite framework allows the breaking of the above model. The optimized catalyst exhibits more than 99% regioselectivity to n-butanal and more than 99% selectivity to aldehydes at a product formation turnover frequency (TOF) of 6,500 h-1, surpassing the performance of all heterogeneous and most homogeneous catalysts developed so far. Our comprehensive studies show that the zeolite framework can act as a scaffold to steer the reaction pathway of the intermediates confined in the space between the zeolite framework and Rh centres towards the exclusive formation of n-butanal.

Tricoordinated Single-Atom Cobalt in Zeolite Boosting Propane Dehydrogenation.

Propane dehydrogenation (PDH) reaction has emerged as one of the most promising propylene production routes due to its high selectivity for propylene and good economic benefits. However, the commercial PDH processes usually rely on expensive platinum-based and poisonous chromium oxide based catalysts. The exploration of cost-effective and ecofriendly PDH catalysts with excellent catalytic activity, propylene selectivity, and stability is of great significance yet remains challenging. Here, we discovered a new active center, i.e., an unsaturated tricoordinated cobalt unit (≡Si-O)CoO(O-Mo) in a molybdenum-doped silicalite-1 zeolite, which afforded an unprecedentedly high propylene formation rate of 22.6 molC3H6 gCo-1 h-1 and apparent rate coefficient of 130 molC3H6 gCo-1 h-1 bar-1 with >99% of propylene selectivity at 550 °C. Such activity is nearly one magnitude higher than that of previously reported Co-based catalysts in which cobalt atoms are commonly tetracoordinated, and even superior to that of most of Pt-based catalysts under similar operating conditions. Density functional theory calculations combined with the state-of-the-art characterizations unravel the role of the unsaturated tricoordinated Co unit in facilitating the C-H bond-breaking of propane and propylene desorption. The present work opens new opportunities for future large-scale industrial PDH production based on inexpensive non-noble metal catalysts.

A Fine Analysis of Zn Species Structure and Distribution in Zn/ZSM-5 Catalysts by Linear Combination Fitting Analysis of XANES Spectra.

Investigating the distribution of different Zn species on Zn-containing zeolite catalysts is crucial for identifying the active sites and establishing the relationship between the catalyst's structure and its activity in the process of ethylene aromatization. By utilizing X-ray absorption near edge spectra (XANES) of various reference samples, this study employed linear combination fitting (LCF) analysis on XANES spectra of real samples to accurately measure the changes in the distribution of Zn species in Zn-containing HZSM-5 zeolites under different Zn sources and loadings. The results showed that ZnOH+, ZnO clusters, and ZnO crystalline structures coexist in Zn/HZSM-5 catalysts prepared through physical mixing and incipient wet impregnation methods. A similar trend was observed for catalysts prepared using different methods, with an increase in Zn content resulting in a decrease in the proportion of ZnOH+ and a significant increase in the amount of larger ZnO crystals. Furthermore, ZnO clusters were confined within the zeolite pores. The findings of this study established a direct correlation between the amount of ZnOH+ determined through LCF analysis and both the rate of hydrogen production and the rate of aromatics formation, providing strong evidence for the catalytic role of ZnOH+ as an active center for dehydrogenation, which plays a key role in promoting the formation of aromatics. The method of LCF analysis on XANES spectra allows for the determination of the local structure of Zn species, facilitating a more precise analysis based on the distribution of these species. This method not only provides detailed information about the Zn species but also enhances the accuracy of the overall analysis.

The Effect of Water Co-Feeding on the Catalytic Performance of Zn/HZSM-5 in Ethylene Aromatization Reactions.

During the methanol-to-aromatics (MTA) process, a large amount of water is generated, while the influence and mechanism of water on the activity and selectivity of the light olefin aromatization reaction are still unclear. Therefore, a study was conducted to systematically investigate the effects of water on the reactivity and the product distribution in ethylene aromatization using infrared spectroscopy (IR), intelligent gravitation analyzer (IGA), and X-ray absorption fine structure (XAFS) characterizations. The results demonstrated that the presence of water reduced ethylene conversion and aromatic selectivity while increasing hydrogen selectivity at the same contact time. This indicated that water had an effect on the reaction pathway by promoting the dehydrogenation reaction and suppressing the hydrogen transfer reaction. A detailed analysis using linear combination fitting (LCF) of Zn K-edge X-ray absorption near-edge spectroscopy (XANES) on Zn/HZSM-5 catalysts showed significant variations in the state of existence and the distribution of Zn species on the deactivated catalysts, depending on different reaction atmospheres and water contents. The presence of water strongly hindered the conversion of ZnOH+ species, which served as the active centers for the dehydrogenation reaction, to ZnO on the catalyst. As a result, the dehydrogenation activity remained high in the presence of water. This study using IR and IGA techniques revealed that water on the Zn/HZSM-5 catalyst inhibited the adsorption of ethylene on the zeolite, resulting in a noticeable decrease in ethylene conversion and a decrease in aromatic selectivity. These findings contribute to a deeper understanding of the aromatization reaction process and provide data support for the design of efficient aromatization catalysts.

Direct transformation of nitriles to cyanide using chloride anion as catalyst.

A simple method is explored for the scission of C-CN bonds into aldehyde and CN- in air. The transformation was mediated by chloride anions. The cyanide anions were extracted from the reaction solution to form (Et4N)2[Zn(CN)4] and (Et4N)2[Ni(CN)4]. A chloride-induced reaction mechanism is proposed based on experimental studies and DFT calculations. This work might guide the study of halogen catalysts for C-C bond cleavage.

Venetoclax dose adjustment due to drug-drug interactions: a case report and literature review.

The primary aim of the study is to discuss the potential interactions between venetoclax and common drugs used in department of hematology and the corresponding effects on the efficacy and safety of venetoclax treatment. Here, we report an acute myeloid leukemia patient treated with venetoclax and posaconazole, and the dose of venetoclax was adjusted due to drug interactions. Clinical pharmacists actively participated in treatment of this patient to provide pharmacy care to assist clinicians to identify the venetoclax-induced liver function impairment and give timely management. The case reported here is hoped to provide reference for clinical venetoclax treatment in patients with such disease. Clinical pharmacists should actively participate in clinical treatment, actively screen potential drug interactions, strengthen cooperation and communication with doctors, provide patients with high-quality pharmaceutical services, and establish clinical pharmacists' status in the multidisciplinary treatment of tumor.

Iodine-Mediated Heterocyclization for the Synthesis of 6-Alkylthio-1,3,5-triazine-2,4-diamines from N-Alkylpyridinium Salts and NH4SCN.

An iodine-mediated method for the synthesis of 6-alkylthio-1,3,5-triazine-2,4-diamines by the reaction of N-alkylpyridinium salts and NH4SCN in air is reported. Twenty-seven compounds were obtained under the standard conditions. Pyridinium salts work as benzyl-group transfer reagents to promote the formation of the CBn-SSCN bond and thereby the construction of the triazine skeleton. A plausible mechanism is proposed based on the experimental results and literature survey.

π-Extension of Indoles Using Acrolein Linker: Synthesis of Indolo[3,2-a]carbazole-6-carbaldehydes and Racemosin B.

A simple method for the synthesis of indolo[3,2-a]carbazole-6-carbaldehydes by the π-extension of indoles with acrolein is reported. The scope of the method is demonstrated with 33 examples. The products exhibit high activities toward advanced synthesis and are proved to be able to produce valuable chemicals, such as natural products, dyes, and organic fluorescent materials. In addition, the alkaloid racemosin B can be prepared by this method in two steps in ∼50% overall yield.

Constructing Intrapenetrated Hierarchical Zeolites with Highly Complete Framework via Protozeolite Seeding.

Creation of intrapenetrated mesopores with open highway from external surface into the interior of zeolite crystals are highly desirable that can significantly improve the molecular transport and active sites accessibility of microporous zeolites to afford enhanced catalytic properties. Here, different from traditional zeolite-seeded methods that generally produced isolated mesopores in zeolites, nanosized amorphous protozeolites with embryo structure of zeolites were used as seeds for the construction of single-crystalline hierarchical ZSM-5 zeolites with intrapenetrated mesopores (mesopore volume of 0.51 cm3 g-1 ) and highly complete framework. In this strategy, in contrast to the conventional synthesis, only a small amount of organic structure directing agents and a low crystallization temperature were adopted to promise the protozeolites as the dominant growth directing sites to induce crystallization. The protozeolite nanoseeds provided abundant nucleation sites for surrounding precursors to be crystallized, followed by oriented coalescence of crystallites resulting in the formation of intrapenetrated mesopores. The as-prepared hierarchical ZSM-5 zeolites exhibited ultra-long lifetime of 443.9 hours and a high propylene selectivity of 47.92 % at a WHSV of 2 h-1 in the methanol-to-propylene reaction. This work provides a facile protozeolite-seeded strategy for the synthesis of intrapenetrated hierarchical zeolites that are highly effective for catalytic applications.

Enhancement of the dimethyl ether carbonylation activation via regulating acid sites distribution in FER zeolite framework.

The carbonylation of dimethyl ether (DME) with CO is a key step for ethanol synthesis from syngas, but traditional mordenite (MOR) zeolite shows low catalytic stability. Herein, various FER zeolite nanosheets were prepared with four types of organic templates. The catalytic performance of FER in DME carbonylation is strongly dependent on the location of strong acid site in framework, which can be effectively regulated by altering organic template. FER-MORP sample synthesized with morpholine shows the highest DME conversion of 53%, thus, giving a methyl acetate space-time yield (STYMA) of 0.889 mmol g-1 h-1. DFT calculation, NH3-IR, 1H/27Al/29Si MAS NMR, and in situ DRIFTS results indicate that morpholine directs more Al species, or strong Brønsted acid sites (BAS), to locate in 8-membered ring (8-MR) channels, which not only enhances carbonylation activity but also suppresses formation of coke species. The catalytic performance is well maintained within 4 repeated recycles (∼460 h).

Copper-Catalyzed Oxidative [3 + 2] Cycloaddition of N-Alkyl Pyridinium Salts to Imidazo[1,2-a]pyridines.

A copper-catalyzed reaction of pyridinium salts and trimethylsilyl cyanide (TMSCN) in the presence of diethyl phosphite is developed. This reaction, which allows the single-step construction of biologically important 2-cyanoimidazo[1,2-a]pyridine from readily available starting materials, is realized for the first time and is feasible at the gram scale. The scope of the protocol is demonstrated with 27 examples. A consecutive double cyanation and cyclization can be achieved in this one-pot process. TMSCN plays a dual role not only as the "CN" source but also as the coupling partner for the cyclization of imidazo[1,2-a]pyridines.

Synthesis of N,O-bidentate organic difluoroboron complexes and their photophysical studies.

We disclose a novel boron trifluoride induced C-H activation and difluoroboronation at room temperature, thus providing a straightforward gateway to a series of N,O-bidentate organic BF2 complexes. The scope of the method is demonstrated with 24 examples. All the synthesized compounds exhibit fluorescence and some of them have large Stokes shifts.

Selective conversion of CO2 to isobutane-enriched C4 alkanes over InZrOx-Beta composite catalyst.

Direct conversion of CO2 to a single specific hydrocarbon with high selectivity is extremely attractive but very challenging. Herein, by employing an InZrOx-Beta composite catalyst in the CO2 hydrogenation, a high selectivity of 53.4% to butane is achieved in hydrocarbons (CO free) under 315 °C and 3.0 MPa, at a CO2 conversion of 20.4%. Various characterizations and DFT calculation reveal that the generation of methanol-related intermediates by CO2 hydrogenation is closely related to the surface oxygen vacancies of InZrOx, which can be tuned through modulating the preparation methods. In contrast, the three-dimensional 12-ring channels of H-Beta conduces to forming higher methylbenzenes and methylnaphthalenes containing isopropyl side-chain, which favors the transformation of methanol-related intermediates to butane through alkyl side-chain elimination and subsequent methylation and hydrogenation. Moreover, the catalytic stability of InZrOx-Beta in the CO2 hydrogenation is considerably improved by a surface silica protection strategy which can effectively inhibit the indium migration.

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.

Efficacy of azithromycin in treating Ureaplasma urealyticum: a systematic review and meta-analysis.

BACKGROUND: Ureaplasma urealyticum is the most prevalent genital mycoplasma isolated from the urogenital tract of females, but there is no unified treatment plan. This study aimed to evaluate the efficacy of azithromycin in treating Ureaplasma urealyticum. METHODS: From the earliest to June 2022, published randomized controlled trials (RCTs) on azithromycin treatment of Ureaplasma urealyticum were retrieved by searching PubMed, Embase, Cochrane Library, and Web of Science. Two reviewers independently extracted the data. We utilized the Cochrane risk-of-bias assessment technique to assess the quality of included RCTs. The data were analyzed using the R language (version 4.0.4) software. RESULTS: Seven RCTs were finally included, involving 512 participants (240 in the experimental group, 272 in the control group). The experimental group was treated with azithromycin monotherapy, while the control group was treated with doxycycline or a placebo. Meta-analysis results suggested that azithromycin has a comparable therapeutic effect on Ureaplasma urealyticum in comparison to that of controls (risk ratio [RR] = 1.03, 95% confidence interval [CI] 0.94-1.12). Subgroup analysis showed that the dose and duration of azithromycin may don't affect its efficacy. CONCLUSION: Regarding the meta-analysis that we performed based on existing clinical studies, azithromycin is quite effective in treating Ureaplasma urealyticum.

The correlation between paclitaxel chemotoxicity and the plasma albumin level in cancer patients.

WHAT IS KNOWN AND OBJECTIVE: The aim of this study was to evaluate the pharmacokinetics of paclitaxel in cancer patients with hypoalbuminemia following paclitaxel-containing chemotherapy and to provide a reference for the prevention of adverse events (AEs) after paclitaxel administration. METHODS: Peripheral blood was collected from cancer patients treated with paclitaxel. The plasma concentration of paclitaxel was determined by ultra-high performance liquid chromatography after 24 ± 8 h of chemotherapy, and individual paclitaxel time above a threshold concentration of 0.05 µmol/L (Tc>0.05 ) was calculated using the population pharmacokinetic model. Haematological and non-haematological toxicities were monitored after chemotherapy, and the correlation between different chemotherapy toxicities and Tc>0.05 was evaluated using the Prism software. RESULTS AND DISCUSSION: The enrolled patients were divided into the hypoalbuminemia group and normal albumin level group. The mean Tc>0.05 values in the normal albumin level and hypoalbuminemia groups were 36.89 and 24.93 h, respectively (P < 0.001). The risk of myelosuppression was positively correlated with Tc>0.05 . Due to the lower Tc>0.05 , the incidences of immediate AEs such as gastrointestinal reactions and rashes were higher in the hypoalbuminemia group than in the normal albumin level group, and the incidences of delayed AEs such as myelosuppression and neurotoxicity were lower in the hypoalbuminemia group. WHAT IS NEW AND CONCLUSIONS: Plasma albumin level has a conclusive effect on Tc>0.05 , which can predict the potential clinical toxicity of paclitaxel. The study provides a theoretical basis for administration of paclitaxel.

Three-Component Cycloaddition of Nitriles: Construction of Bicyclic 4-Aminopyrimidines and Their Photophysical Studies.

A base-induced synthesis of bicyclic 4-aminopyrimidines by the cycloaddition of three types of nitriles is reported. The scope of the method is demonstrated with 44 examples. Products are found to have luminescence properties and show potential applications as organic luminescent layer materials.

CO2 Hydrogenation on Metal-Organic Frameworks-Based Catalysts: A Mini Review.

Conversion of carbon dioxide (CO2) into value-added fuels and chemicals can not only reduce the emission amount of CO2 in the atmosphere and alleviate the greenhouse effect but also realize carbon recycling. Through hydrogenation with renewable hydrogen (H2), CO2 can be transformed into various hydrocarbons and oxygenates, including methanol, ethanol, methane and light olefins, etc. Recently, metal-organic frameworks (MOFs) have attracted extensive attention in the fields of adsorption, gas separation, and catalysis due to their high surface area, abundant metal sites, and tunable metal-support interface interaction. In CO2 hydrogenation, MOFs are regarded as important supports or sacrificed precursors for the preparation of high-efficient catalysts, which can uniformly disperse metal nanoparticles (NPs) and enhance the interaction between metal and support to prevent sintering and aggregation of active metal species. This work summarizes the recent process on hydrogenation of CO2 to methanol, methane and other C2+ products over various MOFs-based catalysts, and it will provide some dues for the design of MOFs materials in energy-efficient conversion and utilization.

Copper(II)-Catalyzed Selective CAr-H Bond Formylation: Synthesis of Dialdehyde Aniline.

A simple and efficient method for the synthesis of dialdehyde aniline in good yields (up to 83%) is explored using Cu(OTf)2 as the catalyst, Selectfluor as the radical initiator, and DMSO as both the carbon and oxygen sources. Experimental studies indicate that the reaction is achieved by the formylation of two CAr-H bonds, first at the para-position and then at the ortho-position. A possible mechanism is proposed, including the thermal homolysis of Selectfluor, the Cu(II)-facilitated formylation of the CAr-H bonds, and the hydrolysis of the amide under alkaline conditions in air atmosphere.