59486-57-6Relevant academic research and scientific papers
Vibrational excitation of the allene-fluorine reaction in cryogenic matrices: Possible mode selectivity
Knudsen, Arne K.,Pimentel, George C.
, p. 6780 - 6792 (1983)
The infrared induced reaction of allene (C3H4) and fluorine in N2, Ar, Kr, and Xe matrices at 12 K has been studied.The reaction is promoted by the selective vibrational excitation of C3H4*F2 reactive pairs and the course of the reaction followed by infrared spectroscopy.Four products are detected, consistent with the concerted addition of F2 across the C-C double bond to form vibrationally excited cis- and gauche-CH2CFCH2F which may then eliminate HF to yield either CHCCH2F*HF or CH2=C=CHF*HF pairs.The relative abundance of each product depends markedly upon the matrix.Selective vibrational photoisomerization of CH2=CFCH2F was used to distinguish and assign spectral features due to the cis- and gauche-rotameters as well as to provide evidence about the torsional barrier in the matrix.In a particular matrix, the allene-fluorine reaction product distribution is independent of the exciting frequency, with measurements at 1679, 1953, 1999, and 3076 cm-1.However, the relative quantum yield at 3076 cm-1 is three orders of magnitude higher than observed at the lower frequencies.Furthermore, the quantum yields at 1680, 1953, and 1999 cm-1 show differences that implicate mode selectivity in the allene-fluorine reaction.The CH2 rocking overtone 2ν9 at 1999 cm-1 and perhaps as well the CH2 bending overtone 2ν10 at 1679 cm-1 show a higher reaction propensity than that of the asymmetric skeletal stretching vibration ν6 at 1953 cm-1.
Dehydrofluorination and dehydrogenation of fluorinated alkanes
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, (2008/06/13)
Fluorinated alkanes are converted into correspond-ing unsaturated dehydrofluorination products by contact with a catalyst bed containing γ-fluorided alumina in the presence of a co-reactant gas at a reaction temperature of from about 200°C to about 700°C, the catalyst bed having been prepared by the steps of (a) flowing air over a catalyst bed containing γ-alumina for a contact time of from about 5 seconds to about 150 seconds, at a temperature of from about 600°C to about 750°C, and (b) thereafter flowing hydrogen fluoride over the air-treated catalyst bed at elevated temperature to convert the γ-alumina to γ--fluorided alumina. The co-reactant gas contains oxygen, carbon dioxide or mixtures thereof. The γ-fluorided alumina-containing catalyst may also be utilized to convert 1,1-difluoroethane to its dehydrogenation product, vinylidene fluoride at a reaction temperature of from about 300°C to about 700°C.
