Reaction mechanism of ethanol dehydration on/in heteropoly compounds: Analysis of transient behavior based on pseudo-liquid catalysis model

In a continuous flow system, transformation of diethylamine over heteropoly compounds was studied at 250 to 350 °C. It was found that ammonium molybdophosphate and tungstophosphate are the most active catalysts while copper molybdophosphate is the most stable one. 12-Molybdophosphoric acid and its salts were highly selective catalysts for dehydrogenation of diethylamine to ethyliden- ethylamine whereas 12-tungstophosphoric acid and its salts directed the reaction selectively to deamination. The role of Lewis acidity of metal cations, Bronsted acidity and basic sites in the reaction mechanism is discussed.

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Ultrastructure of Some Planktonic Formainifera

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050962 ◽

1974 ◽

Vol 32 ◽

pp. 190-191

Author(s):

William H. Zucker

Keyword(s):

Cell Biology ◽

Water Mass ◽

Planktonic Foraminifera ◽

Uranyl Acetate ◽

Ethanol Dehydration ◽

Globigerinoides Ruber ◽

Light Microscope Level ◽

Globigerina Bulloides ◽

Glutaraldehyde Solution ◽

Diamond Knife

Planktonic foraminifera are widely-distributed and abundant zooplankters. They are significant as water mass indicators and provide evidence of paleotemperatures and events which occurred during Pleistocene glaciation. In spite of their ecological and paleological significance, little is known of their cell biology. There are few cytological studies of these organisms at the light microscope level and some recent reports of their ultrastructure.Specimens of Globigerinoides ruber, Globigerina bulloides, Globigerinoides conglobatus and Globigerinita glutinata were collected in Bermuda waters and fixed in a cold cacodylate-buffered 6% glutaraldehyde solution for two hours. They were then rinsed, post-fixed in Palade's fluid, rinsed again and stained with uranyl acetate. This was followed by graded ethanol dehydration, during which they were identified and picked clean of debris. The specimens were finally embedded in Epon 812 by placing each organism in a separate BEEM capsule. After sectioning with a diamond knife, stained sections were viewed in a Philips 200 electron microscope.

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The significance of SEM in the diagnosis of haematopoietic malignancies

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100082431 ◽

1978 ◽

Vol 36 (2) ◽

pp. 314-315

Author(s):

Etienne de Harven ◽

Nina Lampen

Keyword(s):

Room Temperature ◽

Culture Medium ◽

Cell Attachment ◽

Ethanol Dehydration ◽

Moist Chamber ◽

Efficient Alternative ◽

Mononuclear Leucocytes ◽

Fast Quenching ◽

Freeze Dryer ◽

Scanning Electron

Samples of heparinized blood, or bone marrow aspirates, or cell suspensions prepared from biopsied tissues (nodes, spleen, etc. ) are routinely prepared, after Ficoll-Hypaque concentration of the mononuclear leucocytes, for scanning electron microscopy. One drop of the cell suspension is placed in a moist chamber on a poly-l-lysine pretreated plastic coverslip (Mazia et al., J. Cell Biol. 66:198-199, 1975) and fifteen minutes allowed for cell attachment. Fixation, started in 2. 5% glutaraldehyde in culture medium at room temperature for 30 minutes, is continued in the same fixative at 4°C overnight or longer. Ethanol dehydration is immediately followed by drying at the critical point of CO2 or of Freon 13. An efficient alternative method for ethanol dehydrated cells is to dry the cells at low temperature (-75°C) under vacuum (10-2 Torr) for 30 minutes in an Edwards-Pearse freeze-dryer (de Harven et al., SEM/IITRI/1977, 519-524). This is preceded by fast quenching in supercooled ethanol (between -90 and -100°C).

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Elemental analysis of human erythrocytes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015318x ◽

1989 ◽

Vol 47 ◽

pp. 242-243

Author(s):

S. A. Livesey ◽

A. A. del Campo ◽

E. S. Griffey ◽

D. Ohlmer ◽

T. Schifani ◽

...

Keyword(s):

Sample Preparation ◽

Elemental Analysis ◽

Human Erythrocyte ◽

Spectroscopic Analysis ◽

Model System ◽

Human Erythrocytes ◽

List Type ◽

Chemical Fixation ◽

Ethanol Dehydration ◽

Lowicryl K4m

The aim of this study is to compare methods of sample preparation for elemental analysis. The model system which is used is the human erythrocyte. Energy dispersive spectroscopic analysis has been previously reported for cryofixed and cryosectioned erythrocytes. Such work represents the reference point for this study. The use of plastic embedded samples for elemental analysis has also been documented. The work which is presented here is based on human erythrocytes which have been either chemically fixed and embedded or cryofixed and subsequently processed by a variety of techniques which culminated in plastic embedded samples.Heparinized and washed erythrocytes were prepared by the following methods for this study :(1). Chemical fixation in 4% paraformaldehyde/0.25% glutaraldehyde/0.2 M sucrose in 0.1 M Na cacodylate, pH 7.3 for 30 min, followed by ethanol dehydration, infiltration and embedding in Lowicryl K4M at -20° C.

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Arylation of enelactams using TIPSOTf: reaction scope and mechanistic insight

Organic Chemistry Frontiers ◽

10.1039/d0qo01396j ◽

2021 ◽

Author(s):

Tomasz J. Idzik ◽

Zofia M. Myk ◽

Łukasz Struk ◽

Magdalena Perużyńska ◽

Gabriela Maciejewska ◽

...

Keyword(s):

Reaction Mechanism ◽

Multinuclear Nmr ◽

Mechanistic Insight ◽

Nmr Study ◽

Wide Range

Triisopropylsilyltrifluoromethanesulfonate can be effectively used for the arylation of a wide range of enelactams. The multinuclear NMR study provided deep insights into the reaction mechanism.

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