Friedel-Crafts Catalysts and Polymerization

1947 ◽  
Vol 20 (2) ◽  
pp. 375-376 ◽  
Author(s):  
A. G. Evans ◽  
G. W. Meadows ◽  
M. Polanyi
Keyword(s):  
Gas Phase ◽  
Boron Trifluoride ◽  
High Vacuum ◽  
Polymerization Reaction ◽  
Catalyzed Polymerization

Abstract In an earlier communication, evidence was given on which the following conclusion was based. In the dimerization of diisobutene and the polymerization of isobutene, it is essential that a trace of some third component, X, shall be present in addition to the monomer and the Friedel-Crafts catalyst, in order that the reaction shall proceed at an appreciable rate. It was suggested then that this third component was probably water. We have continued this line of investigation by studying the boron trifluoride-catalyzed polymerization of isobutene in the gas phase, using high-vacuum technique. The polymerization reaction was followed by mixing the boron trifluoride and the isobutene in the gas phase and measuring the fall in pressure with time. We may summarize the results as follows:

Chemisorption of ethylene on nickel surfaces with preadsorbed oxygen

1981 ◽  
Vol 46 (2) ◽  
pp. 340-353
Author(s):  
Pavel Zachař ◽  
Zdeněk Bastl ◽  
Jakub Adámek
Keyword(s):  
Gas Phase ◽  
Phase Analysis ◽  
Oxygen Concentration ◽  
Electrical Resistance ◽  
High Vacuum ◽  
Volumetric Method ◽  
Surface Oxygen ◽  
Oxygen Chemisorption ◽  
Thin Polycrystalline ◽  
Total Adsorption

Chemisorption of ethylene was studied on thin polycrystalline layers of nickel prepared by metal deposition in high vacuum and modified by preadsorbed oxygen. The volumetric method combined with the gas-phase analysis and the measurement of the electrical resistance changes of these layers were used. Already small amounts of preadsorbed oxygen of the order of 10-2 of the monolayer affect rather substantially the extent of ethylene chemisorption. The extent of the initial irreversible chemisorption and also the total adsorption of ethylene as a function of the amount of preadsorbed oxygen have a maximum at the surface oxygen concentration of 3 . 1013 molecule cm-2. The adsorption accompanied by the extensive dissociation of ethylene C-H bonds proceeds predominantly on nickel atoms with lower coordination (atoms on the microcrystal edges, corner atoms, etc.), where also oxygen chemisorption proceeds preferentially.

Low Temperature Laser-Assisted Gas Phase Reactivity of TMGa with NH3 and Oxygen-Containing Compounds (H2O, CH3OH, O(CH3)2) in Constrained Pulsed Expansions

2002 ◽  
Vol 743 ◽  
Author(s):  
Alexander Demchuk ◽  
Michael Lynch ◽  
Steven Simpson ◽  
Brent Koplitz
Keyword(s):  
Gas Phase ◽  
Vacuum Chamber ◽  
Cluster Formation ◽  
High Vacuum ◽  
Oxygen Species ◽  
Quadrupole Mass ◽  
High Vacuum Chamber ◽  
Arf Excimer Laser ◽  
Gas Nozzle ◽  
193 Nm

ABSTRACTThe present work reports on the study of III-V gas phase reactivity in constrained gas pulse expansions of trimethylgallium (TMGa) and oxygen derivative compounds (H2O, CH3OH, O(CH3)2) with and without ammonia. The precursors are introduced separately into a high vacuum chamber via a multipulsed gas nozzle assembly. The gas mixtures are then exposed to a UV pulse from an ArF excimer laser (λ=193 nm) and the products are mass analyzed with a quadrupole mass spectrometer. The efficient laser-assisted growth of Ga-O-containing clusters in the form of [(CH3)2GaOR] x, where R is H or CH3, has been revealed. Different behavior can be seen in the reaction of TMG and the oxygen species depending on the presence of H atoms bonded to the oxygen. Significant influence of NH3 on cluster formation and oxygen incorporation is demonstrated.

Fluorescence resonance energy transfer of gas-phase ions under ultra high vacuum and ambient conditions

2014 ◽  
Vol 16 (19) ◽  
pp. 8911-8920 ◽  
Author(s):  
Vladimir Frankevich ◽  
Vitaliy Chagovets ◽  
Fanny Widjaja ◽  
Konstantin Barylyuk ◽  
Zhiyi Yang ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Gas Phase ◽  
Fluorescence Resonance Energy Transfer ◽  
High Vacuum ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Ultra High Vacuum ◽  
Ambient Conditions ◽  
Gas Phase Ions ◽  
Fluorescence Resonance

Gas-phase enthalpies of adduct formation: dimethylamine-chloroform and ethyl acetate-boron trifluoride

1968 ◽  
Vol 7 (8) ◽  
pp. 1484-1488 ◽  
Author(s):  
Lawrence J. Sacks ◽  
Russell S. Drago ◽  
Darrell P. Eyman
Keyword(s):  
Ethyl Acetate ◽  
Gas Phase ◽  
Boron Trifluoride ◽  
Adduct Formation
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