scholarly journals A Use-Store-Reuse (USR) Concept in Catalytic HCOOH Dehydrogenation: Case-Study of a Ru-Based Catalytic System for Long-Term USR under Ambient O2

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 481
Author(s):  
Marinos Theodorakopoulos ◽  
Maria Solakidou ◽  
Yiannis Deligiannakis ◽  
Maria Louloudi
Keyword(s):  
Catalytic System ◽  
Water System ◽  
Catalytic Efficiency ◽  
Ambient Air ◽  
Catalytic Performance ◽  
H2 Production ◽  
Repeated Use ◽  
Biphasic Catalytic System ◽  
First Time

Commercial use of H2 production catalysts requires a repeated use/stop/store and reuse of the catalyst. Ideally, this cycle should be possible under ambient O2. Herein we exemplify the concept of Use-Store-Reuse (USR) of a (Ru-phosphine) catalyst in a biphasic catalytic system, for H2 production via dehydrogenation of HCOOH. The catalytic system can operate uninterrupted for at least four weeks, including storage and reuse cycles, with negligible loss of its catalytic efficiency. The catalytic system consisted of a RuP(CH2CH2PPh2)3 (i.e. RuPP3) in (tri-glyme/water) system, using KOH as a cocatalyst, to promote HCOOH deprotonation. In a USR cycle of 1 week, followed by storage for three weeks under ambient air and reuse, the system achieved in total TONs > 90,000 and TOFs > 4000 h−1. Thus, for the first time, a USR concept with a readily available stable ruthenium catalyst is presented, operating without any protection from O2 or light, and able to retain its catalytic performance.

scholarly journals Enhanced Photocatalytic Activity and Stability in Hydrogen Evolution of Mo6 Iodide Clusters Supported on Graphene Oxide

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1259
Author(s):  
Marta Puche ◽  
Rocío García-Aboal ◽  
Maxim A. Mikhaylov ◽  
Maxim N. Sokolov ◽  
Pedro Atienzar ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Gas Phase ◽  
Hybrid Material ◽  
Liquid Water ◽  
Catalytic Performance ◽  
H2 Production ◽  
Cluster Compound ◽  
Catalytic Systems ◽  
Active Cluster ◽  
First Time

Catalytic properties of the cluster compound (TBA)2[Mo6Ii8(O2CCH3)a6] (TBA = tetrabutylammonium) and a new hybrid material (TBA)2Mo6Ii8@GO (GO = graphene oxide) in water photoreduction into molecular hydrogen were investigated. New hybrid material (TBA)2Mo6Ii8@GO was prepared by coordinative immobilization of the (TBA)2[Mo6Ii8(O2CCH3)a6] onto GO sheets and characterized by spectroscopic, analytical, and morphological techniques. Liquid and, for the first time, gas phase conditions were chosen for catalytic experiments under UV–Vis irradiation. In liquid water, optimal H2 production yields were obtained after using (TBA)2[Mo6Ii8(O2CCH3)a6] and (TBA)2Mo6Ii8@GO) catalysts after 5 h of irradiation of liquid water. Despite these remarkable catalytic performances, “liquid-phase” catalytic systems have serious drawbacks: the cluster anion evolves to less active cluster species with partial hydrolytic decomposition, and the nanocomposite completely decays in the process. Vapor water photoreduction showed lower catalytic performance but offers more advantages in terms of cluster stability, even after longer radiation exposure times and recyclability of both catalysts. The turnover frequency (TOF) of (TBA)2Mo6Ii8@GO is three times higher than that of the microcrystalline (TBA)2[Mo6Ii8(O2CCH3)a6], in agreement with the better accessibility of catalytic cluster sites for water molecules in the gas phase. This bodes well for the possibility of creating {Mo6I8}4+-based materials as catalysts in hydrogen production technology from water vapor.

scholarly journals High Catalytic Performance and Sustainability of Zr Modified Aluminophosphate for Vapor-Phase Selective O-methylation of Catechol with Methanol

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 740
Author(s):  
Xinfeng Ren ◽  
Dongfei Xu ◽  
Yuchen Yin ◽  
Xiujing Zou ◽  
Yankai Wang ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Low Cost ◽  
Catalytic Efficiency ◽  
Catalytic Performance ◽  
Weak Acid ◽  
Molar Ratio ◽  
Solid Catalysts ◽  
Long Term Stability ◽  
Calcined Temperature

Guaiacol produced by O-methylation of catechol with methanol over solid catalysts is a green environmental synthesis route. In order to achieve high catalytic efficiency, it is quite necessary to employ low-cost catalysts with high activity and stability. Herein, series of aluminophosphate catalysts were synthesized by a simple precipitation route modified by Zr. The characterization results indicated that the prepared Al-P-Zr catalysts possessed appropriate weak acid and weak base sites, which were beneficial for the O-methylation of catechol with methanol. Different Zr amount and calcined temperature exerted a significant influence on physicochemical properties of the catalysts and catalytic performance. The Al-P-Zr catalysts containing Zr/Al molar ratio of 0.012 calcined under 400 °C showed the optimal catalytic activity and long-term stability for vapor-phase selective O-methylation of catechol with methanol.

scholarly journals Comparative study between the Titanium Phosphate TiP2O7 and the Phosphate Fertilizers in the catalysis of the Quinazolin-4(3H)-one derivatives synthesis

2020 ◽  
Vol 10 (6) ◽  
pp. 553
Author(s):  
Youssef Merroun ◽  
Soukaina Chehab ◽  
Tourya Ghailane ◽  
Rachida Ghailane ◽  
Said Boukhris ◽  
...  
Keyword(s):  
Reaction Times ◽  
Catalytic Efficiency ◽  
Titanium Phosphate ◽  
Triple Superphosphate ◽  
X Ray Diffraction ◽  
Phosphate Fertilizers ◽  
X Ray ◽  
High Yields ◽  
First Time

A simple and efficient method for the synthesis of quinazolin-4(3H)-one derivatives via condensation of anthranilamide with aromatic aldehyde catalyzed by monoammonium phosphate (MAP), diammonium phosphate (DAP), and triple superphosphate (TSP), were developed.  The modification of these three phosphate fertilizers using titanium tetrachloride (TiCl<sub>4</sub>) has increased their catalytic efficiency. The prepared titanium phosphate (TiP<sub>2</sub>O<sub>7</sub>) was characterized using microscopic and spectroscopic methods, namely X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and infrared spectroscopy (IR). The TiP<sub>2</sub>O<sub>7</sub> was applied for the first time as a heterogeneous catalyst in quinazolin-4(3H)-ones synthesis. High yields and short reaction times were observed in the determined optimal condition (solvent nature, volume, and catalyst amount). This study shows that the TiP<sub>2</sub>O<sub>7</sub> presents an exciting catalytic activity and long-term durability compared to those of MAP, DAP, and TSP.

41. Diffusion Badges as a Long-Term, Low-Level Method of Ambient Air Analysis

2005 ◽  
Author(s):  
K. Parker ◽  
S. Rose-Pehrsson ◽  
D. Kidwell
Keyword(s):  
Ambient Air ◽  
Air Analysis ◽  
Low Level ◽  
Level Method

Somatic Embryogenesis and In vitro Plant Regeneration in Vigna trilobata (L.) Verd. - A Potential Pasture Legume

1970 ◽  
Vol 19 (1) ◽  
pp. 89-99
Author(s):  
K. Choudhary ◽  
M. Singh ◽  
M. S. Rathore ◽  
N. S. Shekhawat
Keyword(s):  
Somatic Embryogenesis ◽  
Growth Regulators ◽  
Somatic Embryos ◽  
Basal Medium ◽  
Long Term Study ◽  
Continuous Application ◽  
First Time ◽  
Pasture Legume

This long term study demonstrates for the first time that it is possible to propagate embryogenic Vigna trilobata and to subsequently initiate the differentiation of embryos into complete plantlets. Initiation of callus was possible on 2,4-D. Somatic embryos differentiated on modified MS basal nutrient medium with 1.0 mg/l  of 2,4-D and 0.5 mg/l  of Kn. Sustained cell division resulted in globular and heart shape stages of somatic embryos. Transfer of embryos on to a fresh modified MS basal medium with 0.5 mg/l of Kn and 0.5 mg/l of GA3 helped them to attain maturation and germination. However, the propagation of cells, as well as the differentiation of embryos, were inhibited by a continuous application of these growth regulators. For this reason, a long period on medium lacking these growth regulators was necessary before the differentiation of embryos occurred again. The consequences for improving the propagation of embryogenic cultures in Vigna species are discussed. Key words: Pasture  legume, Vigna trilobata, Globular, Heart shape, somatic embryogenesis D.O.I. 10.3329/ptcb.v19i1.4990 Plant Tissue Cult. & Biotech. 19(1): 89-99, 2009 (June)

An Evaluation of Provincial Macroeconomic Performance in Vietnam

2017 ◽  
pp. 34-47
Author(s):  
Hoi Le Quoc ◽  
Nam Pham Xuan ◽  
Tuan Nguyen Anh
Keyword(s):  
Development Strategy ◽  
Institutional Transformation ◽  
Economic Indicators ◽  
Macroeconomic Performance ◽  
Economic Development Strategy ◽  
Socio Economic Development ◽  
The Cost ◽  
Development Objectives ◽  
First Time

The study was targeted at developing a methodology for constructing a macroeconomic performance index at a provincial level for the first time in Vietnam based on 4 groups of measurements: (i) Economic indicators; (ii) oriented economic indicators; (iii) socio-economic indicators; and (iv) economic - social – institutional indicators. Applying the methodology to the 2011 - 2015 empirical data of all provinces in Vietnam, the research shows that the socio-economic development strategy implemented by those provinces did not provide balanced outcomes between growth and social objectives, sustainability and inclusiveness. Many provinces focused on economic growth at the cost of structural change, equality and institutional transformation. In contrast, many provinces were successful in improving equality but not growth. Those facts threaten the long-term development objectives of the provinces.

Cobalt/Lewis Acid Catalysis for Hydrocarbofunctionalization of Alkynes via Cooperative C–H Activation

2020 ◽  
Author(s):  
Chang-Sheng Wang ◽  
Sabrina Monaco ◽  
Anh Ngoc Thai ◽  
Md. Shafiqur Rahman ◽  
Chen Wang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Lewis Acid ◽  
Hydrogen Transfer ◽  
Acid Catalysis ◽  
Rate Limiting Step ◽  
Site Selectivity ◽  
Set Up ◽  
Site Selective ◽  
First Time ◽  
Rate Limiting

A catalytic system comprised of a cobalt-diphosphine complex and a Lewis acid (LA) such as AlMe3 has been found to promote hydrocarbofunctionalization reactions of alkynes with Lewis basic and electron-deficient substrates such as formamides, pyridones, pyridines, and azole derivatives through site-selective C-H activation. Compared with known Ni/LA catalytic system for analogous transformations, the present catalytic system not only feature convenient set up using inexpensive and bench-stable precatalyst and ligand such as Co(acac)3 and 1,3-bis(diphenylphosphino)propane (dppp), but also display distinct site-selectivity toward C-H activation of pyridone and pyridine derivatives. In particular, a completely C4-selective alkenylation of pyridine has been achieved for the first time. Mechanistic stidies including DFT calculations on the Co/Al-catalyzed addition of formamide to alkyne have suggested that the reaction involves cleavage of the carbamoyl C-H bond as the rate-limiting step, which proceeds through a ligand-to-ligand hydrogen transfer (LLHT) mechanism leading to an alkyl(carbamoyl)cobalt intermediate.

NEW VARIETIES OF CURRANTS AND GOOSEBERRY BREEDING PLANTS

1970 ◽  
pp. 41-46
Author(s):  
O. D. Golyaeva ◽  
O. V. Kurashev ◽  
S. D. Knyazev ◽  
А. Yu. Bakhotskaya
Keyword(s):  
Powdery Mildew ◽  
Genetic Basis ◽  
Black Currant ◽  
Leaf Spots ◽  
Agricultural Sciences ◽  
Berry Crops ◽  
New Varieties ◽  
First Time ◽  
Red Currant

The main goal of the scientific institution was and remains to improve the assortment of fruit and berry crops for the development of domestic horticulture. Black currant breeding at VNIISPK was started by A.F Tamarova and continued by the doctor of agricultural Sciences T.P.Ogoltsova and doctor of agricultural Sciences S.D. Knyazev. A long-term breeding program has been developed. The main goals of the program are to create black currant cultivars with continuous resistance to diseases, first of all powdery mildew, as wells resistance to pests, i.e. bud mite. As a result of the long-term work, over 40 black currant cultivars have been developed, 14 of them are zoned. Red currant breeding was led by the candidate of agricultural Sciences L.V. Bayanova; since 2001 the work has been continued by the candidate of agricultural Sciences O.D. Golyaeva. ‘Heinemanns Rote Spӓtlese’, the descendant of R. multiflorum Kit., was involved in the red currant breeding for the first time in Russia. On its genetic basis, a series of late maturing cultivars with long and dense racemes was created. At the Institute, in total 21cultivars of red currants have been developed, 13 of them are zoned. At present, red currant cultivars make up 25.5% of the zoned assortment in Russia. The first research on gooseberries was stated by V.P. Semakin and A.F Tamarova; since 1992 the systematic gooseberry breeding has been carried out by the candidate of agricultural Sciences O.V. Kurashev. On the basis of Grossularia robusta, we have created gooseberry forms that are resistant to powdery mildew and leaf spots. These forms are highly productive, weakly thorned, having bush habit suitable for mechanized harvest. The result of breeding activities was the transfer of 6 gooseberry cultivars to State agricultural testing: ‘Solnechny Zaychik’, ‘Nekrasovsky’, ‘Yupiter’, ‘Zemlianichny’, ‘Moryachok’ and ‘Discovery’.

Sign in / Sign up

Export Citation Format

Share Document