Reactivity of Interstitial Cl− Anions in Synthetic Hydrotalcite-Like Materials in the Halide Exchange Reaction with Alkyl Halides

1994 ◽  
Vol 368 ◽  
Author(s):  
Esteban López-Salinas ◽  
Yoshio Ono ◽  
Eiichi Suzuki
Keyword(s):  
Exchange Reaction ◽  
Benzyl Chloride ◽  
Reaction Rate ◽  
Alkyl Halides ◽  
Butyl Chloride ◽  
Butyl Bromide ◽  
Catalytic Behavior ◽  
Interlayer Region ◽  
Halide Exchange ◽  
Complex Anions

ABSTRACTTwo types of synthetic hydrotalcite-like [Mg6Al2(OH)16 ][An−%D;2/n (HT) were prepared where A = Cl− anions (Cl-HT), and NiC42− complex anions (NiCl-HT), in order to examine: (1) the reactivity of Cl− anion (or ligand) towards alkyl halides and (2) their catalytic behavior in the Finkelstein reaction. For instance, 0.4 g of NiCl-HT (Cl−: 1.41 mmol) suspended in 20 cm3 of toluene with 14.1 mmol of butyl bromide at 373 K yielded 42 % butyl chloride after 15 min of reaction. In comparison, NiCl4(Et4N)2 (precursor to prepare NiCl-HT) yielded at the same conditions only 2.4 % of butyl chloride. This indicates a great mobility of Cl− in the interlayer region of HTs. The reaction rate is greatly accelerated using DMF instead of toluene and butanol totally suppressed it. This is consistent with a SN2 mechanism. The halide-exchange reaction between benzyl chloride and butyl bromide is catalyzed by both Cl-HT and NiCl-HT.

On the relationship between the rate constants for racemization and isotopic exchange

1998 ◽  
Vol 76 (6) ◽  
pp. 643-648 ◽  
Author(s):  
John MW Scott ◽  
Danny Summers
Keyword(s):  
Transition State ◽  
Exchange Reaction ◽  
Rate Constants ◽  
Isotopic Exchange ◽  
Alkyl Halides ◽  
Sufficient Condition ◽  
Isotopic Exchange Kinetics ◽  
Halide Exchange ◽  
Exchange Kinetics ◽  
The Relationship

The relationship between the rate constants that describe the halide ion catalysis of the racemization (kr) of optically alkyl halides and the related isotopic halide exchange reaction (ke) is shown to be valid in two distinct cases. The first is when the racemization and exchange mechanisms follow the classical and conventional SN2 path characterized by a symmetrical trigonal (sp2) transition state. The second envisages the trigonal species characteristic of the SN2 reaction as an intermediate instead of a transition state. The latter mechanism is also shown to be characterized by the relationship kr = 2ke, and hence this diagnostic test is seen to be a necessary but not a sufficient condition for invoking the SN2 mechanism.Key words: racemization, isotopic exchange, kinetics, bimolecular substitution, inversion.

Hydrogen isotope exchange between D2 and H2O catalyzed by platinum plate

1989 ◽  
Vol 67 (5) ◽  
pp. 857-861 ◽  
Author(s):  
Shin-Ichi Miyamoto ◽  
Tetsuo Sakka ◽  
Matae Iwasaki
Keyword(s):  
Kinetic Model ◽  
Exchange Reaction ◽  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Reaction Rate ◽  
Hydrogen Adsorption ◽  
Platinum Catalyst ◽  
Isotope Exchange Reaction ◽  
Hydrogen Isotope Exchange ◽  
Supported Platinum

The reaction rate of hydrogen isotope exchange between D2 and H2O catalyzed by platinum plate is studied. The exchange reaction is described with the kinetic model which is the modification of that for the exchange reaction catalyzed by alumina-supported platinum catalyst. For the comparison of experimental results with this model relative amount of the number of sites for hydrogen adsorption was estimated from the initial rate of hydrogen isotope exchange between H2 and D2 on the same surface. The results show that the kinetic model is applicable for the plate catalyst if the number of the sites for hydrogen absorption, which is very sensitive to the surface state of the catalyst, was estimated not from the macroscopic surface area but from our scheme. Keywords: hydrogen isotope exchange reaction, platinum plate as catalyst.

scholarly journals SYNTHESIS AND ANTIMICROBIAL EVALUATION OF SOME NEW BENZTHIAZOLE OXIME ETHER DERIVATIVES

2021 ◽  
Vol 11 (6) ◽  
pp. 47-50
Author(s):  
Sachin V Patil
Keyword(s):  
Biological Activities ◽  
Alkyl Halides ◽  
Ethyl Chloride ◽  
Absolute Ethanol ◽  
Spectroscopic Methods ◽  
Butyl Chloride ◽  
Oxime Ether ◽  
Antimicrobial Evaluation ◽  
Oxime Derivatives

Some new oxime ether derivatives containing benzthiazole heterocyclic nuclei are synthesized. The reaction of 2-mercapto benzthiazole with α-halo ketones followed by reaction with hydroxylamine gave oxime derivatives which on reaction with alkyl halides viz. ethyl chloride, n-propyl chloride, and n-butyl chloride in absolute ethanol afforded the target compounds 4a-l. The structure of all the synthesized compounds was confirmed by spectroscopic methods like mass and NMR. All compounds after structural confirmation were tested for biological activities.

Pandora's box of binary tungsten iodides

2019 ◽  
Vol 48 (5) ◽  
pp. 1547-1561 ◽  
Author(s):  
Markus Ströbele ◽  
Hans-Jürgen Meyer
Keyword(s):  
Partial Pressure ◽  
Exchange Reaction ◽  
New Synthesis ◽  
Halide Exchange

More than 20 binary tungsten iodides have been discovered. This was possible due to a new synthesis of W3I12 through halide exchange reaction and by thermal scanning. Depending on the I2 partial pressure compounds can incorporate or release I2. On heating they undergo self-reduction. Some tungsten iodide clusters can be directly transferred into solution.

Homogeneous Catalysis of Hydrogen Isotope Exchange Between D2 and Ethanol by Chlorotris(triphenyIphosphine)rhodium(I). II. In Chloroform-Ethanol

1974 ◽  
Vol 52 (12) ◽  
pp. 2226-2235 ◽  
Author(s):  
Graeme Strathdee ◽  
Russell Given
Keyword(s):  
Activation Energy ◽  
Computer Simulation ◽  
Exchange Reaction ◽  
Homogeneous Catalysis ◽  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Reaction Rate ◽  
Side Reaction ◽  
Rate Determining Step ◽  
Inverse Isotope Effect

The kinetics and mechanism of D2 exchange catalyzed by RhCl(PPh3)3 have been studied in chloroform–ethanol solutions. Interpretation of the results was complicated by a side reaction of the solvent to yield HCl, RhHCl2(PPh3)2, C2H5Cl, CH2Cl2, Ph3PO, and other phosphorus(V) species. Computer simulation of the exchange reaction was used to show that the observed inverse isotope effect [Formula: see text] could arise only if the rate determining step was the activation of D2, HD, and H2 by RhCl(PPh3)3.The D2 exchange reaction rate was extremely dependent on solvent composition and decreased 30 times between 6 and 96 mol% C2H5OH. The activation energy for D2 exchange was 101 ± 9 kJ mol−1 at 58 mol% C2H5OH, and 86 ± 8 kJ mol−1 at 6 mol% C2H5OH. These data suggested that solvent–catalyst bonding interactions were important.

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