Acyl-und Alkylidenarsane, V [1] (Dimethylaminomethyliden)-phenylar8an, ein acyclisches Alkylidenarsan / Acyl-and Alkylidenearsines, V [1] (Dimethylaminomethylidene)-phenylarsine, an Acyclic Alkylidenearsine

1981 ◽  
Vol 36 (9) ◽  
pp. 1080-1084 ◽  
Author(s):  
Gerd Becker ◽  
Angelika Münch ◽  
Hans-Jürgen Wessely
Keyword(s):  
Sodium Hydroxide ◽  
Nmr Spectra ◽  
Dimethylamino Group

Abstract Alkylidenearsines, Aminomethylidenearsines, Barrier of Rotation In the absence of a catalyst phenyl-bis(trimethylsilyl)arsine (1 a) reacts only very slowly with excess dimethylformamide (4) to give (dimethylaminomethylidene)-phenylarsine (8 a) and hexamethyldisiloxane (5). In the presence of small amounts of solid sodium hydroxide, however, the reaction is already finished after four days at + 20 °C. Similarly, lithium phenyltrimethylsilylarsenide · DME (2 a), which can easily be obtained from la and methyllithium in 1,2-dimethoxyethane (DME), and dimethylformamide (4) also form the alkylidenearsine (3 a) and lithium trimethylsilanolate. The NMR spectra of 3 a show the rotation of the dimethylamino group to be hindered with a barrier of about 63 kJ · mol-1 .

1H, 13C, and 15N NMR Spectra of Ni(II) Complexes of Schiff Bases of (S)-2-(N-Benzylprolyl)aminobenzophenone and α-Monosubstituted Glycine and Determination of Configuration of the Complexes by 2D NOESY Spectra

1995 ◽  
Vol 60 (6) ◽  
pp. 990-998 ◽  
Author(s):  
Josef Jirman ◽  
Alexander Popkov
Keyword(s):  
Schiff Base ◽  
Schiff Bases ◽  
Absolute Configuration ◽  
Nmr Spectra ◽  
Phenyl Group ◽  
15N Nmr ◽  
Dimethylamino Group ◽  
2D Noesy ◽  
Noesy Spectra

1H, 13C, and 15N NMR spectra have been measured of substituted Ni(II) complexes of Schiff bases of (S)-2-(N-benzylprolyl)aminobenzophenone and glycine. The absolute configuration at C19 of the substituted glycine can be determined from 2D NOESY spectra using the NOESY interactions with the proton of the second chiral centre of the complex. It is possible to determine the rate of rotation of phenyl group of benzophenone unless its rotation is prevented by requatorialr orientation of dimethylamino group as it is the case with the Ni(II) complex of Schiff base of (S)-2-(N-benzylprolyl)aminobenzophenone and (S)-α-dimethylaminoglycine.

Thermodynamic properties and H1 and Na23 NMR spectra of sodium hydroxide solutions

1966 ◽  
Vol 6 (3) ◽  
pp. 353-358 ◽  
Author(s):  
G. Z. Mal'tsev ◽  
G. V. Malinin ◽  
V. P. Mashovets ◽  
V. A. Shcherbakov
Keyword(s):  
Thermodynamic Properties ◽  
Sodium Hydroxide ◽  
Nmr Spectra

Rapid Carboxymethylation of Xylan-Rich Hemicelluloses by Microwave Irradiation

2011 ◽  
Vol 236-238 ◽  
pp. 292-296 ◽  
Author(s):  
Xin Wen Peng ◽  
Jun Li Ren ◽  
Feng Peng ◽  
Run Cang Sun
Keyword(s):  
Chemical Modification ◽  
Sodium Hydroxide ◽  
Nmr Spectra ◽  
Gel Permeation Chromatography ◽  
Water Medium ◽  
Reaction Conditions ◽  
Microwave Irradiations ◽  
Gel Permeation ◽  
Before And After ◽  
Wheat Straw Biomass

Rapid carboxymethylation of xylan-rich hemicelluloses from wheat straw biomass with sodium monochloroacetate and sodium hydroxide in the ethanol/water medium under microwave irradiations was investigated in this paper. The effects of reaction conditions such as the reaction time, the reaction temperature, and the amounts of sodium hydroxide and sodium monochloroacetate on the degree substitution (DS) of carboxymethylated hemicelluloses were discussed. The structures of hemicelluloses before and after the chemical modification were analyzed by13C nuclear magnetic resonance (NMR) spectra. Gel permeation chromatography (GPC) was used to characterize the carboxymethylated hemicelluloses. During the chemical modification, it was found that the remarkable degradation of hemicelluloses occurred under microwave irradiations.

Preparation and Characterization of New Heterocyclic Derivatives, Six and Five Ring from Acetanilide

2020 ◽  
pp. 87-89
Keyword(s):  
Physical Properties ◽  
Sodium Hydroxide ◽  
Hydrazine Hydrate ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Room Temperature ◽  
13C Nmr Spectra ◽  
Dilute Solution ◽  
Heterocyclic Derivatives

The aim of the study synthesis of new heterocyclic derivatives (six and five ring) from acetanilide. Firstly the chalcones have been synthesized from the reaction acetanilide with aromatic aldehyde [ 2-nitrobenzaldyhade, 4- dimethylaminobenzaldehyde, 2-naphthaldehyde ] in dilute solution of ethanolic sodium hydroxide at room temperature. This reaction occurs depending on Claisen Schmidt condensation, then a new oxazine and thiazine derivatives (six ring) have been synthesized by the reaction chalcones with urea and thiourea. Finally the synthesized chalcones were reacted with hydrazine hydrate to produce new pyrazol derivatives (five ring). All derivatives were characterized by physical properties, FTIR, 1H-NMR and 13C-NMR spectra.

Comparison of Acrylamide and Agar Gels by Freeze-Etching

1977 ◽  
Vol 35 ◽  
pp. 606-607
Author(s):  
Russell L. Steere ◽  
Eric F. Erbe
Keyword(s):  
Electron Microscope ◽  
Sodium Hydroxide ◽  
Sodium Hypochlorite ◽  
Chromic Acid ◽  
Distilled Water ◽  
Thin Sheets ◽  
Acid Cleaning ◽  
Agar Gels ◽  
Freeze Etching ◽  
Water Cut

Thin sheets of acrylamide and agar gels of different concentrations were prepared and washed in distilled water, cut into pieces of appropriate size to fit into complementary freeze-etch specimen holders (1) and rapidly frozen. Freeze-etching was accomplished in a modified Denton DFE-2 freeze-etch unit on a DV-503 vacuum evaporator.* All samples were etched for 10 min. at -98°C then re-cooled to -150°C for deposition of Pt-C shadow- and C replica-films. Acrylamide gels were dissolved in Chlorox (5.251 sodium hypochlorite) containing 101 sodium hydroxide, whereas agar gels dissolved rapidly in the commonly used chromic acid cleaning solutions. Replicas were picked up on grids with thin Foimvar support films and stereo electron micrographs were obtained with a JEM-100 B electron microscope equipped with a 60° goniometer stage.Characteristic differences between gels of different concentrations (Figs. 1 and 2) were sufficiently pronounced to convince us that the structures observed are real and not the result of freezing artifacts.

Soft ionic liquid based resistive memory characteristics in a two terminal discrete polydimethylsiloxane cylindrical microchannel

2020 ◽  
Vol 8 (38) ◽  
pp. 13368-13374
Author(s):  
Muhammad Umair Khan ◽  
Gul Hassan ◽  
Jinho Bae
Keyword(s):  
Ionic Liquid ◽  
Acrylic Acid ◽  
Sodium Hydroxide ◽  
Sodium Salt ◽  
Resistive Memory ◽  
Cylindrical Microchannel ◽  
Memory Characteristics ◽  
Poly Acrylic Acid

This paper proposes a novel soft ionic liquid (IL) electrically functional device that displays resistive memory characteristics using poly(acrylic acid) partial sodium salt (PAA-Na+:H2O) solution gel and sodium hydroxide (NaOH) in a thin polydimethylsiloxane (PDMS) cylindrical microchannel.

NMR spectra and relaxation in incommensurate systems in the presence of a devil's staircase

1985 ◽  
Vol 46 (7) ◽  
pp. 1205-1209 ◽  
Author(s):  
R. Blinc ◽  
S. Žumer ◽  
D.C. Ailion ◽  
J. Nicponski
Keyword(s):  
Nmr Spectra ◽  
Devil's Staircase ◽  
Devil’S Staircase

Environmental benefits of magnesium hydroxide-based peroxide bleaching of mechanical pulp – mill results

TAPPI Journal ◽  
2013 ◽  
Vol 12 (6) ◽  
pp. 9-15 ◽  
Author(s):  
TOMI HIETANEN ◽  
JUHA TAMPER ◽  
KAJ BACKFOLK
Keyword(s):  
Sodium Hydroxide ◽  
Magnesium Hydroxide ◽  
Oxygen Demand ◽  
Pulp Mill ◽  
Transition Metal Ions ◽  
Environmental Benefits ◽  
Raw Material ◽  
Paper Machine ◽  
High Brightness ◽  
Peroxide Bleaching

The use of a new, technical, high-purity magnesium hydroxide-based peroxide bleaching additive was evaluated in full mill-scale trial runs on two target brightness levels. Trial runs were conducted at a Finnish paper mill using Norwegian spruce (Picea abies) as the raw material in a conventional pressurized groundwood process, which includes a high-consistency peroxide bleaching stage. On high brightness grades, the use of sodium-based additives cause high environmental load from the peroxide bleaching stage. One proposed solution to this is to replace all or part of the sodium hydroxide with a weaker alkali, such as magnesium hydroxide. The replacement of traditional bleaching additives was carried out stepwise, ranging from 0% to 100%. Sodium silicate was dosed in proportion to sodium hydroxide, but with a minimum dose of 0.5% by weight on dry pulp. The environmental effluent load from bleaching of both low and high brightness pulps was significantly reduced. We observed a 35% to 48% reduction in total organic carbon (TOC), 37% to 40% reduction in chemical oxygen demand (COD), and 34% to 60% reduction in biological oxygen demand (BOD7) in the bleaching effluent. At the same time, the target brightness was attained with all replacement ratios. No interference from transition metal ions in the process was observed. The paper quality and paper machine runnability remained good during the trial. These benefits, in addition to the possibility of increasing production capacity, encourage the implementation of the magnesium hydroxide-based bleaching concept.

Improvement in the Fock test for determining the reactivity of dissolving pulp

TAPPI Journal ◽  
2013 ◽  
Vol 12 (11) ◽  
pp. 21-26 ◽  
Author(s):  
CHAO TIAN ◽  
LINQIANG ZHENG ◽  
QINGXIAN MIAO ◽  
CHRIS NASH ◽  
CHUNYU CAO ◽  
...  
Keyword(s):  
Moisture Content ◽  
Sodium Hydroxide ◽  
Constant Temperature ◽  
Carbon Disulfide ◽  
Testing Procedure ◽  
Dissolving Pulp ◽  
Water Bath ◽  
Testing Conditions ◽  
Pulp Sample ◽  
Fock Reactivity

The Fock test is widely used for assessing the reactivity of dissolving pulp. The objective of this study was to modify the method to improve the repeatability of the test. Various parameters that affect the repeatability of the Fock test were investigated. The results showed that Fock reactivity is dependent on testing conditions affecting the xanthation between cellulose and carbon disulfide, such as the moisture content of the pulp sample, sodium hydroxide (NaOH) concentration, xanthation temperature, carbon disulfide dosage, and xanthation time. The repeatability of the test was significantly improved using the following modified testing procedure: air dried sample in the constant temperature/humidity room, xanthation temperature of 66°F (19°C) in a water bath, xanthation time of 3 h, NaOH concentration of 9% (w/w), and 1.3 mL carbon disulfide.

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