scholarly journals Synthesis and Characterization of Pd exchanged MMT Clay for Mizoroki-Heck Reaction

2018 ◽  
Vol 16 (1) ◽  
pp. 605-613 ◽  
Author(s):  
Vivek Srivastava
Keyword(s):  
Heck Reaction ◽  
Exchange Process ◽  
Reaction Medium ◽  
Analytical Techniques ◽  
Catalyst Loading ◽  
Catalyst Recycling ◽  
Mmt Clay ◽  
Vinyl Phosphonates ◽  
Low Catalyst Loading

AbstractWe successfully synthesized Pd@MMT clay using a cation exchange process. We characterized all the synthesized Pd@MMT clays using sophisticated analytical techniques before testing them as a heterogeneous catalyst for the Mizoroki - Heck reaction (mono and double). The highest yield of the Mizoroki-Heck reaction product was recovered using thermally stable and highly reactive Pd@ MMT-1 clay catalyst in the functionalized ionic liquid reaction medium. We successfully isolated 2-aryl-vinyl phosphonates (mono-Mizoroki-Heck reaction product) and 2,2-diaryl-vinylphosphonates (double-Mizoroki-Heck reaction product) using aryl halides and dialkyl vinyl phosphonates in higher yields. The low catalyst loading, easy recovery of reaction product and 8 times catalyst recycling are the major highlights of this proposed protocol.

Active pyridinium based ionic liquid anchored quinuclidine organocatalyst for Morita-Baylis-Hillman reaction

2021 ◽  
Vol 18 ◽  
Author(s):  
Vivek Srivastava
Keyword(s):  
Ionic Liquid ◽  
Analytical Techniques ◽  
Chemical Yield ◽  
Biologically Active ◽  
Catalyst Loading ◽  
Catalyst Recycling ◽  
Ether Extraction ◽  
Different Types ◽  
Low Catalyst Loading

: In the present manuscript, we easily synthesized three different types of ionic liquid supported 3-quinuclidinone organocatalysts such as [PyAmEQ][BF4] (Py-CATALYST-1), [PyAmEQ][PF6] (Py-CATALYST-2), and [PyAmEQ][NTf2] (Py-CATALYST-3). After performing the careful characterization of the above catalysts with sophisticated analytical techniques, we utilized them as a catalyst to study the passive Morita-Baylis-Hillman reaction. The corresponding Morita-Baylis-Hillman adducts were easily isolated, followed by the simple ether extraction method. Moreover, the above protocol also promoted low catalyst loading, short reaction time, wide substrate scope, easy product, and catalyst recycling. We easily recycled the catalytic system for 5 runs with no noticeable loss in the chemical yield. Additionally, Py-CATALYST-3 was also used to prepare biologically active materials, i.e., N-((E,3S,4R)-5-benzylidene-tetrahydro-4-hydroxy-6-oxo-2H-pyran-3-yl) palmitamide derivatives.

Acceleration of Baylis-Hillman reaction using ionic liquid supported organocatalyst

2021 ◽  
Vol 08 ◽  
Author(s):  
Vivek Srivastava
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Reaction Rate ◽  
Reaction Medium ◽  
Catalyst Loading ◽  
Catalyst Recycling ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Highly Active ◽  
Low Catalyst Loading

Background: Baylis-Hillman reaction suffers from the requirement of cheap starting materials, easy reaction protocol, possibility to create the chiral center in the reaction product has increased the synthetic efficacy of this reaction, and high catalyst loading, low reaction rate, and poor yield. Objective: The extensive use of various functional or non-functional ionic liquids (ILs) with organocatalyst increases the reaction rate of various organic transformations as a reaction medium and as a support to anchor the catalysts. Methods: In this manuscript, we have demonstrated the synthesis of quinuclidine-supported trimethylamine-based functionalized ionic liquid as a catalyst for the Baylis-Hillman reaction. Results: We obtained the Baylis-Hillman adducts in good, isolated yield, low catalyst loading, short reaction time, broad substrate scope, accessible product, and catalyst recycling. N-((E,3S,4R)-5-benzylidene-tetrahydro-4-hydroxy-6-oxo-2H-pyran-3-yl) palmitamide was also successfully synthesized using CATALYST-3 promoted Baylis-Hillman reaction. Conclusion: We successfully isolated the 25 types of Baylis-Hillman adducts using three different quinuclidine-supported ammonium-based ionic liquids such as Et3AmQ][BF4] (CATALYST-1), [Et3AmQ][PF6] (CATALYST-2), and [TMAAmEQ][NTf2](CATALYST-3) as new and efficient catalysts. Tedious and highly active N-((E,3S,4R)-5-benzylidene-tetrahydro-4-hydroxy-6-oxo-2H-pyran-3-yl) palmitamide derivative was also synthesized using CATALYST-3 followed by Baylis-Hillman reaction. Generally, all the responses demonstrated higher activity and yielded high competition with various previously reported homogenous and heterogeneous Catalytic systems. Easy catalyst and product recovery followed by six catalysts recycling were the added advantages of the prosed catalytic system.

Three-Component Synthesis of 4-Arylidene-3-alkylisoxazol-5(4H)-ones in the presence of potassium 2,5-dioxoimidazolidin-1-ide

2021 ◽  
Vol 25 ◽  
Author(s):  
Neda Reihani ◽  
Hamzeh Kiyani
Keyword(s):  
Ethylene Glycol ◽  
Ethyl Acetoacetate ◽  
Reaction Medium ◽  
Hydroxylamine Hydrochloride ◽  
Aromatic Aldehydes ◽  
Catalyst Loading ◽  
Efficient Synthesis ◽  
Current Process ◽  
High Yields ◽  
Low Catalyst Loading

: An efficient synthesis of 4-arylidene-3-alkylisoxazole-5(4H)-ones has been implemented via the three-component cyclocondensation of aryl(heteroaryl)aldehydes with hydroxylamine hydrochloride and β-ketoesters. The potassium 2,5-dioxoimidazolidin-1-ide has been introduced as the new organocatalyst to facilitate of this heterocyclization. In the current process, three starting materials, including substituted benzaldehydes/heterocyclic aromatic aldehydes, hydroxylamine hydrochloride, and ethyl acetoacetate/propyl acetoacetate/butyryl acetoacetate have been successfully used for the synthesize of the number of substituted isoxazole-5(4H)-ones in good to high yields in ethylene glycol as a green reaction medium at 80 ºC. The low catalyst loading is also a main advantage over the some reported catalysts.

scholarly journals Ru@hyperbranched Polymer for Hydrogenation of Levulinic Acid to Gamma-Valerolactone: The Role of the Catalyst Support

2022 ◽  
Vol 23 (2) ◽  
pp. 799
Author(s):  
Svetlana A. Sorokina ◽  
Stepan P. Mikhailov ◽  
Nina V. Kuchkina ◽  
Alexey V. Bykov ◽  
Alexander L. Vasiliev ◽  
...  
Keyword(s):  
Levulinic Acid ◽  
Catalyst Support ◽  
Physicochemical Characterization ◽  
Significant Loss ◽  
Catalyst Loading ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Low Catalyst Loading

Hydrogenation of levulinic acid (LA) obtained from cellulose biomass is a promising path for production of γ-valerolactone (GVL)—a component of biofuel. In this work, we developed Ru nanoparticle containing nanocomposites based on hyperbranched pyridylphenylene polymer, serving as multiligand and stabilizing matrix. The functionalization of the nanocomposite with sulfuric acid significantly enhances the activity of the catalyst in the selective hydrogenation of LA to GVL and allows the reaction to proceed under mild reaction conditions (100 °C, 2 MPa of H2) in water and low catalyst loading (0.016 mol.%) with a quantitative yield of GVL and selectivity up to 100%. The catalysts were successfully reused four times without a significant loss of activity. A comprehensive physicochemical characterization of the catalysts allowed us to assess structure-property relationships and to uncover an important role of the polymeric support in the efficient GVL synthesis.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Some applications of electron beam microanalysis techniques in VLSI process evaluation

1983 ◽  
Vol 41 ◽  
pp. 160-161
Author(s):  
Simon Thomas
Keyword(s):  
Integrated Circuits ◽  
Process Evaluation ◽  
Large Scale ◽  
Technology Development ◽  
Analytical Techniques ◽  
Successful Implementation ◽  
Analysis Of Failures ◽  
Characterization Of Materials ◽  
Circuits Vlsi

Trends in the technology development of very large scale integrated circuits (VLSI) have been in the direction of higher density of components with smaller dimensions. The scaling down of device dimensions has been not only laterally but also in depth. Such efforts in miniaturization bring with them new developments in materials and processing. Successful implementation of these efforts is, to a large extent, dependent on the proper understanding of the material properties, process technologies and reliability issues, through adequate analytical studies. The analytical instrumentation technology has, fortunately, kept pace with the basic requirements of devices with lateral dimensions in the micron/ submicron range and depths of the order of nonometers. Often, newer analytical techniques have emerged or the more conventional techniques have been adapted to meet the more stringent requirements. As such, a variety of analytical techniques are available today to aid an analyst in the efforts of VLSI process evaluation. Generally such analytical efforts are divided into the characterization of materials, evaluation of processing steps and the analysis of failures.

A very rapid in situ Kikuchi technique to determine relative crystal misorientation

1988 ◽  
Vol 46 ◽  
pp. 830-831
Author(s):  
J. I. Bennetch
Keyword(s):  
Electron Beam ◽  
Analytical Techniques ◽  
Superplastic Forming ◽  
The Other ◽  
Kikuchi Pattern ◽  
Kikuchi Line ◽  
Line Analysis

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.

Comparison of Ion-Milling Techniques For Cross-Sectional TEM of Semiconductors

1985 ◽  
Vol 43 ◽  
pp. 166-167
Author(s):  
Julia T. Luck ◽  
C. W. Boggs ◽  
S. J. Pennycook
Keyword(s):  
Analytical Techniques ◽  
Sample Surface ◽  
Ion Milling ◽  
Cross Sectional ◽  
Reliable Technique ◽  
Near Surface ◽  
Transmission Electron ◽  
Thin Region ◽  
Transient Thermal

The use of cross-sectional Transmission Electron Microscopy (TEM) has become invaluable for the characterization of the near-surface regions of semiconductors following ion-implantation and/or transient thermal processing. A fast and reliable technique is required which produces a large thin region while preserving the original sample surface. New analytical techniques, particularly the direct imaging of dopant distributions, also require good thickness uniformity. Two methods of ion milling are commonly used, and are compared below. The older method involves milling with a single gun from each side in turn, whereas a newer method uses two guns to mill from both sides simultaneously.

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