Metal complex-assisted polymerization of thermosetting resins: a convenient one-step procedure for the preparation of heterogeneous catalysts

2010 ◽  
pp. 229-232 ◽  
Author(s):  
Ulrich Arnold ◽  
Manfred Döring
Keyword(s):  
Metal Complex ◽  
Heterogeneous Catalysts ◽  
Thermosetting Resins ◽  
Step Procedure ◽  
One Step

Synthesis of Polycycles and Oxacycles by Tandem Metathesis of endo–norbornene Derivatives

Synthesis ◽  
2021 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Sunil Pulletikurti ◽  
Ambareen Fatma ◽  
gopal dhangar ◽  
gonna somu Naidu
Keyword(s):  
Natural Products ◽  
Metal Complex ◽  
Carbonyl Group ◽  
Single Step ◽  
Time Dependent ◽  
Computational Studies ◽  
Nmr Studies ◽  
Tricyclic Compounds ◽  
One Step ◽  
Norbornene Derivatives

Here, we have demonstrated that the presence of a carbonyl group at C7 position is preventing the olefin metathesis of endo-norbornene derivatives due to the complexation of the metal alkylidene. Time-dependent NMR studies showed the presence of new proton signals in the metal alkylidene region, which indicate the formation of metal complex with the carbonyl group of the substrate. These observations were further proved by ESI-MS analysis. Whereas, computational studies provided that the catalyst was interacting with the C7 carbonyl group and aligned perpendicular to that of norbornene olefin. Later, these endo-keto norbornene derivatives were reduced to hydroxyl derivatives diastereoselectively. Ring-rearrangement metathesis (RRM) of these hydroxyl derivatives, produced the [6/5/6], and [5/6/5] carbo-tricyclic cores of the natural products in one step. Whereas the RRM of O-allyl derivatives, delivered the oxa-tricyclic compounds in a single step with excellent yields.

scholarly journals Electrochromic Performance and Capacitor Performance of α-MoO3 Nanorods Fabricated by a One-Step Procedure

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 783
Author(s):  
Ying Duan ◽  
Chen Wang ◽  
Jian Hao ◽  
Yang Jiao ◽  
Yanchao Xu ◽  
...  
Keyword(s):  
Growth Parameters ◽  
Average Diameter ◽  
Fast Response ◽  
Cycle Stability ◽  
Electrochromic Devices ◽  
Step Procedure ◽  
One Step ◽  
Supercapacitor Performance ◽  
First Time ◽  
Prepared Nanorods

In this paper, we propose for the first time the synthesis of α-MoO3 nanorods in a one-step procedure at mild temperatures. By changing the growth parameters, the microstructure and controllable morphology of the resulting products can be customized. The average diameter of the as-prepared nanorods is about 200 nm. The electrochromic and capacitance properties of the synthesized products were studied. The results show that the electrochromic properties of α-MoO3 nanorods at 550 nm have 67% high transmission contrast, good cycle stability and fast response time. The MoO3 nanorods also exhibit a stable supercapacitor performance with 98.5% capacitance retention after 10,000 cycles. Although current density varies sequentially, the nanostructure always exhibits a stable capacitor to maintain 100%. These results indicate the as-prepared MoO3 nanorods may be good candidates for applications in electrochromic devices and supercapacitors.

One-step procedure for the preparation of tertiary .alpha.-ketols from the corresponding ketones

1968 ◽  
Vol 33 (8) ◽  
pp. 3294-3297 ◽  
Author(s):  
J. N. Gardner ◽  
F. E. Carlon ◽  
O. Gnoj
Keyword(s):  
Step Procedure ◽  
One Step

An innovative and efficient method to synthesize meloxicam in one-step procedure with respect to the green chemistry

2018 ◽  
Vol 16 (3) ◽  
pp. 501-509 ◽  
Author(s):  
Pierrick Dufrénoy ◽  
Alina Ghinet ◽  
Marie Hechelski ◽  
Adam Daïch ◽  
Christophe Waterlot
Keyword(s):  
Green Chemistry ◽  
Efficient Method ◽  
Step Procedure ◽  
One Step

scholarly journals An effective GC method for the determination of the fatty acid composition in silkworm pupae oil using a two-step methylation process

2015 ◽  
Vol 80 (1) ◽  
pp. 9-20 ◽  
Author(s):  
Jun Wang ◽  
Weiwei Wu ◽  
Xudong Wang ◽  
Min Wang ◽  
Fuan Wu
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Methyl Esters ◽  
Superior Performance ◽  
Step Procedure ◽  
Silkworm Pupae ◽  
Chromatographic Procedure ◽  
One Step ◽  
Synthesis Yield

In search of an accurate and effective method to determine fatty acid composition in silkworm pupae oils, five methylation methods were evaluated for use in the gas chromatographic (GC) quantitation of fatty acid methyl esters (FAMEs), including one-step esterification catalyzed by an acidic (H2SO4 and BF3) or alkali catalyst (KOH and NaOCH3) and a two-step procedure catalyzed successively by KOH and H2SO4. These methods were comparatively adopted to quantify FAMEs in silkworm pupae oil using GC-MS and GC and then validate their precision, stability and average recovery rates. The results indicated that compared with the other four methyl esterification methods, two-step methylation effectively improves the synthesis yield of FAMEs, conserves agents, and eliminates the usage of potential harmful reagents. The proposed GC method has been validated, shows good accuracy and precision, and has been applied successfully to the quantification of FAMEs in several varieties of silkworm pupae oils. The short analytical run time leads to low costs and a fast chromatographic procedure. In summary, two-step pretreatment had superior performance, providing technical references for the determination and analysis of fatty acids in other oils.

scholarly journals An Oligoimide Particle as a Pickering Emulsion Stabilizer

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1071 ◽  
Author(s):  
Yu-Jin Cho ◽  
Dong-Min Kim ◽  
In-Ho Song ◽  
Ju-Young Choi ◽  
Seung-Won Jin ◽  
...  
Keyword(s):  
Particle Concentration ◽  
Pickering Emulsion ◽  
Pickering Emulsions ◽  
Step Method ◽  
Wetting Properties ◽  
Emulsion Droplets ◽  
Step Procedure ◽  
Oil In Water ◽  
One Step ◽  
Oil Emulsions

A pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA)-based oligoimide (PMDA-ODA) was synthesized by a one-step procedure using water as a solvent. The PMDA-ODA particles showed excellent partial wetting properties and were stably dispersed in both water and oil phases. A stable dispersion was not obtained with comparison PMDA-ODA particles that were synthesized by a conventional two-step method using an organic solvent. Both oil-in-water and water-in-oil Pickering emulsions were prepared using the oligoimide particles synthesized in water, and the size of the emulsion droplet was controlled based on the oligoimide particle concentration. The oligoimide particles were tested to prepare Pickering emulsions using various kinds of oils. The oil-in-water Pickering emulsions were successfully applied to prepare microcapsules of the emulsion droplets. Our new Pickering emulsion stabilizer has the advantages of easy synthesis, no need for surface modification, and the capability of stabilizing both oil-in-water and water-in-oil emulsions.

scholarly journals Microwave-Assisted Vacuum Synthesis of TiO2 Nanocrystalline Powders in One-Pot, One-Step Procedure

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 149
Author(s):  
Enrico Paradisi ◽  
Roberto Rosa ◽  
Giovanni Baldi ◽  
Valentina Dami ◽  
Andrea Cioni ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Sol Gel ◽  
Reaction Medium ◽  
Process Intensification ◽  
Nanocrystalline Powders ◽  
Fast Heating ◽  
One Pot ◽  
Nanoparticle Suspension ◽  
Step Procedure ◽  
One Step

A new method for fast and simple synthesis of crystalline TiO2 nanoparticles with photocatalytic activity was developed by carrying out a classic sol–gel reaction directly under vacuum. The use of microwaves for fast heating of the reaction medium further reduces synthesis times. When the solvent is completely removed by vacuum, the product is obtained in the form of a powder that can be easily redispersed in water to yield a stable nanoparticle suspension, exhibiting a comparable photocatalytic activity with respect to a commercial product. The present methodology can, therefore, be considered a process intensification procedure for the production of nanotitania.

scholarly journals Update on Simultaneous Topo-guided Photorefractive Keratectomy Immediately Followed by Corneal Collagen Cross-linking for Treatment of Progressive Keratoconus

2012 ◽  
Vol 1 (3) ◽  
pp. 185-189 ◽  
Author(s):  
George Kymionis ◽  
Sonia Yoo ◽  
Vardhaman Kankariya ◽  
George Kontadakis
Keyword(s):  
Basic Problem ◽  
Corneal Transplantation ◽  
New Combination ◽  
Photorefractive Keratectomy ◽  
Cross Linking ◽  
Effective Technique ◽  
Step Procedure ◽  
One Step ◽  
Collagen Cross Linking ◽  
Corneal Collagen

ABSTRACT Corneal collagen cross-linking (CXL) is a safe and effective technique for the management of corneal ecstatic disorders. It has been proven that CXL is effectual in stopping the progression of keratoconus quasi ‘freezing’ the cornea and in many cases avoiding corneal transplantation. Nevertheless, patients’ basic problem, which is the deterioration of their vision due to irregular astigmatism, remains. CXL combined with topography-guided photorefractive keratectomy (PRK) has been developed in order to achieve an important goal. To offer patients stability of their disorder and at the same time to assist them in achieving a functional vision by improving topographic outcomes. This article discusses update on this new combination therapy in the form of topo-guided PRK immediately followed by CXL as one-step procedure for treatment of progressive keratoconus. How to cite this article Kankariya V, Kymionis G, Kontadakis G, Yoo S. Update on Simultaneous Topo-guided Photorefractive Keratectomy Immediately Followed by Corneal Collagen Cross- linking for Treatment of Progressive Keratoconus. Int J Kerat Ect Cor Dis 2012;1(3):185-189.

scholarly journals Affinity chromatography and inhibition of chorismate mutase-prephenate dehydrogenase by derivatives of phenylalanine and tyrosine

1977 ◽  
Vol 165 (1) ◽  
pp. 121-126 ◽  
Author(s):  
G D Smith ◽  
D V Roberts ◽  
A Daday
Keyword(s):  
Affinity Chromatography ◽  
Competitive Inhibitor ◽  
Chorismate Mutase ◽  
Prephenate Dehydrogenase ◽  
Step Procedure ◽  
One Step ◽  
High Degree ◽  
Sepharose 4B ◽  
Derivatives Of

Several derivatives of phenylalanine and tyrosine were prepared and tested for inhibition of chorismate mutase-prephenate dehydrogenase (EC 1.3.1.12) from Escherichia coli K12 (strain JP 232). The best inhibitors were N-toluene-p-sulphonyl-L-phenylalanine, N-benzenesulphonyl-L-phenylalanine and N-benzloxycarbonyl-L-phenylalanine. Consequently two compounds, N-toluene-sulphonyl-L-p-aminophenylalanine and N-p-aminobenzenesulphonyl-L-phenylalanine, were synthesized for coupling to CNBr-activated Sepharose-4B. The N-toluene-p-sulphonyl-L-p-aminophenylalanine-Sepharose-4B conjugate was shown to bind the enzyme very strongly at pH 7.5. The enzyme was not eluted by various eluents, including 1 M-NaCl, but could be quantitatively recovered by washing with buffer of pH9. Elution was more effective in the presence of 10 mM-1-adamantaneacetic acid, a competitive inhibitor of the enzyme. This affinity-chromatography procedure results in a high degree of purification of the enzyme and can be used to prepare the enzyme in a one-step procedure from the bacterial crude extract. Such a procedure may therefore prove useful in studying this enzyme in a state that closely resembles that in vivo.

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