Reactions最新文献_第8页

The Alkyne Zipper Reaction: A Useful Tool in Synthetic Chemistry 炔拉链反应:合成化学中的一个有用工具

Reactions Pub Date : 2022-12-30 DOI: 10.3390/reactions4010002

Åshild Moi Sørskår, Helge Ø. K. Stenstrøm, Y. Stenstrøm, S. Antonsen

引用次数: 0

Hydrothermal Synthesis of Vanadium Oxide Microstructures with Mixed Oxidation States 水热合成具有混合氧化态的氧化钒微结构

Reactions Pub Date : 2022-12-28 DOI: 10.3390/reactions4010001

D. Navas

{"title":"Hydrothermal Synthesis of Vanadium Oxide Microstructures with Mixed Oxidation States","authors":"D. Navas","doi":"10.3390/reactions4010001","DOIUrl":"https://doi.org/10.3390/reactions4010001","url":null,"abstract":"This review is based on hydrothermal synthetic procedures that generate different vanadium oxide microstructures with mixed oxidation states, where different vanadium (V5+) precursors (vanadate, vanadium oxide, vanadium alkoxide, etc.,) are used to obtain various types of morphologies and shapes, such as sea urchins, cogs, stars, squares, etc., depending on the amphiphilic molecules (usually surfactants) exhibiting a structural director role containing an organic functional group such as primary amines and thiols, respectively. The performance of sol–gel methodology, where intercalation processes sometimes take place, is crucial prior to the hydrothermal treatment stage to control the V4+/V5+. In every synthesis, many physical and chemical parameters, such as temperature, pH, reaction time., etc., are responsible for influencing the reactions in order to obtain different products; the final material usually corresponds to a mixed oxidation state structure with different content rates. This feature has been used in many technological applications, and some researchers have enhanced it by functionalizing the products to enhance their electrochemical and magnetic properties. Although some results have been auspicious, there are a number of projects underway to improve the synthesis in many ways, including yield, secondary products, size distribution, oxidation state ratio, etc., to achieve the best benefits from these microstructures in the large number of technological, catalytic, and magnetic devices, among other applications.","PeriodicalId":20873,"journal":{"name":"Reactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86187490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Study of the Synthetic Approach Influence in Ni/CeO2-Based Catalysts for Methane Dry Reforming 合成方法对Ni/ ceo2基甲烷干重整催化剂影响的研究

Reactions Pub Date : 2022-12-16 DOI: 10.3390/reactions3040043

M. Pizzolato, Giulia Da Pian, E. Ghedini, A. di Michele, F. Menegazzo, G. Cruciani, M. Signoretto

{"title":"Study of the Synthetic Approach Influence in Ni/CeO2-Based Catalysts for Methane Dry Reforming","authors":"M. Pizzolato, Giulia Da Pian, E. Ghedini, A. di Michele, F. Menegazzo, G. Cruciani, M. Signoretto","doi":"10.3390/reactions3040043","DOIUrl":"https://doi.org/10.3390/reactions3040043","url":null,"abstract":"This study focuses on the synthetic approach influence in morphostructural features and catalytic performances for Ni/CeO2 catalysts. Incipient wetness impregnation, coprecipitation and nitrate combustion were studied as catalyst preparation approaches, and the materials were then tested at 700 °C for methane dry reforming (MDR). The morphostructural properties of the materials were deeply studied using several techniques, such as temperature programmed reduction (TPR), to investigate reducibility and support-metal interaction, N2 physisorption to evaluate the porosity and the surface area, scanning electron microscopy (SEM) and X-ray diffraction (XRD) to estimate Ni dispersion, and temperature programmed oxidation (TPO) to identify the type and amount of coke formed on catalysts’ surface after reaction. From the data obtained, coprecipitation turned out to be the most suitable technique for this application because this catalyst was able to reach 70% of CO2 conversion and 30% methane conversion, with an H2 yield of 15% and 30% yield of CO at the end of the 30 h test. Moreover, it was also the catalyst with the highest metal dispersion, the strongest interaction with the support, and the lowest coke deposition.","PeriodicalId":20873,"journal":{"name":"Reactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88260135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Three-Component Condensation of β-Ketonitriles, 4-Fluorobenzaldehyde, and Secondary Cyclic Amines β-酮腈、4-氟苯甲醛和仲环胺的三组分缩合

Reactions Pub Date : 2022-12-12 DOI: 10.3390/reactions3040042

D. Osipov, K. S. Korzhenko, V. Osyanin

引用次数: 0

Synthesis and Characterization of Multiple Functionalized Cyclohexanone Using Diels–Alder Reaction of α-Nitrocinnamate α-硝基氨基酸酯diols - alder反应合成多功能化环己酮及表征

Reactions Pub Date : 2022-12-02 DOI: 10.3390/reactions3040041

Takumi Hamada, Kento Iwai, N. Nishiwaki

引用次数: 0

Selective O-alkylation of Phenol Using Dimethyl Ether 二甲醚选择性邻烷基化苯酚

Reactions Pub Date : 2022-11-17 DOI: 10.3390/reactions3040040

Mane Samruddhi, Akash Bhatkar, M. Prabu, S. Mekala, P. Gogoi, G. Mohapatra, Raja Thirumalaiswamy

{"title":"Selective O-alkylation of Phenol Using Dimethyl Ether","authors":"Mane Samruddhi, Akash Bhatkar, M. Prabu, S. Mekala, P. Gogoi, G. Mohapatra, Raja Thirumalaiswamy","doi":"10.3390/reactions3040040","DOIUrl":"https://doi.org/10.3390/reactions3040040","url":null,"abstract":"Anisole is a straw-colored aromatic compound mainly used in making solvents, flavoring agents, perfumes, fuel additives, and in the synthesis industries. Anisole, also known as methoxybenzene, is synthesized from sodium phenoxide or phenol using various methylating agents. The use of dimethyl ether (DME) as an alkylating agent is seldom reported in the literature. Herein, we have synthesized anisole through the O-alkylation process of phenol and DME to obtain zero discharge from this process. The thermodynamic equilibrium for the reaction of phenol and DME is simulated by using Aspen HYSYS (Hyprotech and Systems). The O-alkylation of phenol has been investigated using phosphotungstic acid (PTA) over γ-Al2O3 with appropriate acidity. Active metal loadings of various percentages were studied and the conversion was optimized at 46.57% with a selectivity of 88.22% at a temperature of 280 °C. The liquid products from the continuously stirred reactor were analyzed with liquid G.C. and the conversion and selectivity were calculated. A comparison of the O-alkylation and C-alkylation of phenol at different temperatures, reactant ratios, residence times, and recyclability was explored, as well as the impact of these factors on the yield of the desired anisole. The catalyst was characterized by XRD, BET, HR-TEM, FE-SEM, elemental mapping, XPS, and DRIFT studies.","PeriodicalId":20873,"journal":{"name":"Reactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81890282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Hydrolytic Oxidation of Cellobiose Using Catalysts Containing Noble Metals 含贵金属催化剂水解氧化纤维素二糖的研究

Reactions Pub Date : 2022-11-16 DOI: 10.3390/reactions3040039

O. Manaenkov, O. Kislitsa, E. Ratkevich, Yu. Kosivtsov, V. Sapunov, V. Matveeva

{"title":"Hydrolytic Oxidation of Cellobiose Using Catalysts Containing Noble Metals","authors":"O. Manaenkov, O. Kislitsa, E. Ratkevich, Yu. Kosivtsov, V. Sapunov, V. Matveeva","doi":"10.3390/reactions3040039","DOIUrl":"https://doi.org/10.3390/reactions3040039","url":null,"abstract":"Studies of the processes of the hydrolytic oxidation of disaccharides are the first step towards the development of technologies for the direct conversion of plant polysaccharides, primarily cellulose, into aldonic and aldaric acids, which are widely used in chemical synthesis and various industries. In this study, heterogeneous catalysts based on a porous matrix of hypercrosslinked polystyrene (HPS) and noble metals (Pt, Au, Ru, and Pd) were proposed for the hydrolytic oxidation of cellobiose to gluconic and glucaric acids. The catalysts were characterized using low-temperature nitrogen adsorption, hydrogen chemisorption, electron microscopy, and other methods. In particular, it was shown that the Pt-containing catalyst contained, on average, six times more active centers on the surface, which made it more promising for use in this reaction. At a temperature of 145 °C, an O2 pressure of 5 bars, and a substrate/catalyst weight ratio of 4/1, the yields of gluconic and glucaric acids reached 21.6 and 63.4%, respectively. Based on the data obtained, the mathematical model of the cellobiose hydrolytic oxidation kinetics in the presence of 3% Pt/HPS MN270 was developed, and the parameter estimation was carried out. The formal description of the kinetics of cellobiose hydrolytic oxidation was obtained.","PeriodicalId":20873,"journal":{"name":"Reactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91266695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Decomposition of Heavy Diesel SCR Urea Fluid Adsorbed in Cu/HZSM-5 SCR Catalysts Studied by FTIR Spectroscopy at Ambient Conditions 常压条件下Cu/HZSM-5 SCR催化剂吸附重柴油SCR尿素液分解研究

Reactions Pub Date : 2022-11-11 DOI: 10.3390/reactions3040038

C. Tempelman, Brahim el Arkoubi, Jochem Spaan, Ronny Slevani, V. Degirmenci

{"title":"Decomposition of Heavy Diesel SCR Urea Fluid Adsorbed in Cu/HZSM-5 SCR Catalysts Studied by FTIR Spectroscopy at Ambient Conditions","authors":"C. Tempelman, Brahim el Arkoubi, Jochem Spaan, Ronny Slevani, V. Degirmenci","doi":"10.3390/reactions3040038","DOIUrl":"https://doi.org/10.3390/reactions3040038","url":null,"abstract":"A method is presented to study the decomposition of urea deposited on Cu/HZSM-5 SCR catalysts and therewith the ability of the Cu/HZSM-5 SCR catalyst to be regenerated when being overdosed with SCR urea fluids during operation. This straightforward laboratory method could speed up calibration of exhaust gas aftertreatment systems. As an example, the removal of adsorbed urea to the SCR substrate due to dosage malfunction is studied. To study the removal of adsorbed urea on the catalyst substrate, FTIR experiments have been conducted to investigate the state of the catalyst. Besides Cu/HZSM-5 also HZSM-5 and CuOx were studied as model compounds to provide more inside on the processes occurring at the Cu/HZSM-5 surface upon urea decomposition. To simulate exposure of the SCR catalyst to overdosing of the urea solution, samples were impregnated with a 32 wt% urea solution, which correlates to that of commercial heavy duty diesel urea solutions. After impregnation, the samples were heated at various temperatures in the 133–400 °C temperature region, typically the operation window of a SCR catalyst. After heating, the samples were cooled to room temperature and measured in FTIR. The obtained spectra were compared with various literature reports to correlate the observed absorption bands to urea, urea related compounds and decomposition compounds. The concentration of these adsorbed species decreases at increased thermolysis temperature and is no longer visible at temperatures >250 °C. Extended heat treatment at 200 °C revealed only minor loss of adsorbents after 6 h and were still observable in the FTIR spectra after 24 h. Urea derived adsorbents were completely removed when simulating catalyst regeneration under SCR operation conditions under continuous air flow with a humidity of 10% and at elevated temperatures (400 °C).","PeriodicalId":20873,"journal":{"name":"Reactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79386085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Azathioprine overdose* 用药过量*

Reactions Pub Date : 2022-11-01 DOI: 10.1007/s40278-022-27485-y

引用次数: 0

Valproic acid 丙戊酸

Reactions Pub Date : 2022-11-01 DOI: 10.1007/s40278-022-27937-6

引用次数: 0