scholarly journals THE REACTION OF DIOXANE WITH HYDROGEN BROMIDE

1951 ◽  
Vol 29 (9) ◽  
pp. 785-789 ◽  
Author(s):  
A. B. Van Cleave ◽  
R. I. Blake
Keyword(s):  
Molecular Weight ◽  
Hydrobromic Acid ◽  
Room Temperature ◽  
Hydrogen Bromide ◽  
Intermediate Compound ◽  
Molecular Weight Determination ◽  
Sample Analysis ◽  
Ethylene Dibromide ◽  
Free Hydrogen ◽  
Oxonium Salt

Dioxane reacted slowly at room temperature with anhydrous, bromine free hydrogen bromide to form 2, 2′-dibromodiethyl ether as a principal product. The 2, 2′-dibromodiethyl ether was characterized by comparison with a known sample, analysis, molecular weight determination, and by conversion to divinyl ether which was subsequently brominated to yield 1, 1′, 2, 2′-tetrabromodiethyl ether. When refluxed with constant boiling hydrobromic acid 2, 2′-dibromodiethyl ether was partially converted to ethylene dibromide. An intermediate compound in the formation of 2, 2′-dibromodiethyl ether from dioxane and hydrogen bromide was isolated by solvent extraction using petroleum ether. Its properties indicated that it was probably an oxonium salt.

scholarly journals Tin Chloride Catalysed Oxidation of Acetone with Hydrogen Peroxide to Tetrameric Acetone Peroxide

1999 ◽  
Vol 23 (4) ◽  
pp. 288-289
Author(s):  
Heng Jiang ◽  
Gang Chu ◽  
Hong Gong ◽  
Qingdong Qiao
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Elemental Analysis ◽  
Room Temperature ◽  
Molecular Weight Determination ◽  
Tin Chloride ◽  
Catalysed Oxidation ◽  
Acetone Peroxide

SnCl4·5H2O and SnCl2·2H2O are efficient catalysts for the oxidation of acetone with 30% hydrogen peroxide at room temperature and produce tetrameric acetone peroxide which is identified by molecular weight determination, elemental analysis, FTIR, NMR and MS.

Degradation in a Methyl-phenyl Co-Polymeric Polysilane for LED Applications

2003 ◽  
Vol 769 ◽  
Author(s):  
Asha Sharma ◽  
Deepak ◽  
Monica Katiyar ◽  
Satyendra Kumar ◽  
V. Chandrasekhar ◽  
...  
Keyword(s):  
Thin Films ◽  
Molecular Weight ◽  
Light Source ◽  
Room Temperature ◽  
Light Exposure ◽  
Room Temperature Photoluminescence ◽  
Pl Spectrum ◽  
Pl Intensity ◽  
Methyl Phenyl

AbstractThe optical degradation of polysilane copolymer has been studied in spin cast thin films and solutions using light source of 325 nm wavelength. The room temperature photoluminescence (PL) spectrum of these films show a sharp emission at 368 nm when excited with a source of 325 nm. However, the PL intensity deteriorates with time upon light exposure. Further the causes of this degradation have been examined by characterizing the material for its transmission behaviour and changes occurring in molecular weight as analysed by GPC data.

Molecular Weight Determination of Component Polypeptides of Glutenin after Fractionation by Gel Filtration

1975 ◽  
Vol 39 (8) ◽  
pp. 1527-1531
Author(s):  
Zen-ichiro Hamauzu ◽  
Yukio Kamazuka ◽  
Hirokazu Kanazawa ◽  
Daizo Yonezawa
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Molecular Weight Determination

scholarly journals Metal- and Oxidant-Free Photoinduced Aromatic Trifluoromethylation Performed in Aerated Gel Media: Determining the Effects on Yield and Selectivity

Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 29 ◽  
Author(s):  
Alex Abramov ◽  
Hendrik Vernickel ◽  
César Saldías ◽  
David Díaz Díaz
Keyword(s):  
Molecular Weight ◽  
Room Temperature ◽  
Homogeneous Solution ◽  
Product Distribution ◽  
Blocking Effect ◽  
Low Molecular Weight ◽  
Metal Free ◽  
Potential Benefits ◽  
Media Concentration ◽  
Reaction Media

In this work we have investigated the potential benefits of using supramolecular gel networks as reaction media to carry out air-sensitive metal-free light-induced trifluoromethylation of six-membered (hetero)arenes under aerobic conditions. This reaction was performed at room temperature (RT) using sodium triflinate (CF3SO2Na, Langlois’ reagent) as a source of radicals and diacetyl as electron donor. The effects of confinement in gel media, concentration of reactants, and type of light source on yield and product distribution were evaluated and compared to the results obtained in homogeneous solution. Four different low molecular weight (LMW) gelators were employed in this study. The results confirmed the blocking effect of the gel medium against reaction quenching by external oxygen, as well as a certain control on the kinetics and selectivity.

scholarly journals Chemical Composition and Thermal Behavior of Kraft Lignins

Forests ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 483 ◽  
Author(s):  
Aleš Ház ◽  
Michal Jablonský ◽  
Igor Šurina ◽  
František Kačík ◽  
Tatiana Bubeníková ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Cost Effective ◽  
Activation Energies ◽  
Industrial Applications ◽  
Raw Material ◽  
Molecular Weight Determination ◽  
Two Samples ◽  
Process Measurements

Lignin has great potential for utilization as a green raw material or as an additive in various industrial applications, such as energy, valuable chemicals, or cost-effective materials. In this study, we assessed a commercial form of lignin isolated using LignoBoost technology (LB lignin) as well as three other types of lignin (two samples of non-wood lignins and one hardwood kraft lignin) isolated from the waste liquors produced during the pulping process. Measurements were taken for elemental analysis, methoxyl and ash content, higher heating values, thermogravimetric analysis, and molecular weight determination. We found that the elemental composition of the isolated lignins affected their thermal stability, activation energies, and higher heating values. The lignin samples examined showed varying amounts of functional groups, inorganic component compositions, and molecular weight distributions. Mean activation energies ranged from 93 to 281 kJ/mol. Lignins with bimodal molecular weight distribution were thermally decomposed in two stages, whereas the LB lignin showing a unimodal molecular weight distribution was decomposed in a single thermal stage. Based on its thermal properties, the LB lignin may find direct applications in biocomposites where a higher thermal resistance is required.

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