Investigation of the effect of hydrogen pressure on the rate of heterogeneous catalytic isomerization of cyclohexane

1960 ◽  
Vol 9 (6) ◽  
pp. 931-935
Author(s):  
I. I. Levitskii ◽  
M. G. Gonikberg
Keyword(s):  
Hydrogen Pressure ◽  
Heterogeneous Catalytic ◽  
Catalytic Isomerization

scholarly journals The catalytic isomerization of buten-1

1941 ◽  
Vol 178 (972) ◽  
pp. 106-117 ◽  
Keyword(s):  
Double Bond ◽  
Hydrogen Pressure ◽  
Square Root ◽  
Double Bond Migration ◽  
Rate Determining Step ◽  
Catalytic Isomerization ◽  
Rate Of Reaction ◽  
Hydrogenation Reactions ◽  
Kinetics Of ◽  
Catalytic Exchange

It has been shown that butene-1 undergoes isomerization to butene-2 on a nickel catalyst in the presence of hydrogen. B y using deuterium, this double-bond migration has been examined simultaneously with the exchange and hydrogenation reactions. The kinetics of double-bond migration and hydrogenation at 65° C were found to be identical, the rate of reaction in both cases being proportional to the square root of the butene pressure and to the square root of the hydrogen pressure. Energies of activation for the three reactions were measured over the temperature range 76-126° C and the following values found: Exchange 9.0 kcal. Hydrogenation 2.5 ,, Double-bond migration 5.9 ,, At the lowest temperatures, the rate of double-bond migration was about six times that of exchange. These facts are in agreement with the theory that the catalytic exchange between olefines and deuterium takes place through the formation of an associative complex. The rate-determining step in the double-bond migration is the second, fast step of the exchange reaction, viz.

Synthesis and Antimicrobial activities of Some Polyphenol compounds by Nano ZnO-TBAB as a Heterogeneous Catalytic Media

2020 ◽  
Vol 17 ◽  
Author(s):  
Rahele Bargebid ◽  
Ali Khalafi-Nezhad ◽  
Kamiar Zomorodian ◽  
Leila Zamani ◽  
Ali Ahmadinejad ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
Antimicrobial Activities ◽  
Reusable Catalyst ◽  
Nano Zno ◽  
Antifungal Activities ◽  
Chemical Structures ◽  
Heterogeneous Catalytic ◽  
Solvent Free Conditions ◽  
New Compounds ◽  
Derivatives Of

Introduction: Mannich reaction is a typical example of a three-component condensation reaction and the chemistry of Mannich bases has been the matter of search by researchers. Here an efficient procedure for the synthesis of some new Mannich derivatives of simple phenols is described. Methods: In this procedure a microwave-assisted and solvent less condensation were done between different phenols, secondary amines and paraformaldehyde. The reactions proceed in the presence of catalytic amount of nano ZnO and tetrabutylammonium bromide (TBAB) in excellent yields. 10 new compounds were synthesized (A1-A10). Chemical structures of all new compounds were confirmed by different spectroscopic methods. We optimized the chemical reactions in different conditions. Optimization reactions were done in the presence of different mineral oxides, different amount of TBAB and also different solvents. Nano ZnO and TBAB in catalytic amounts and solvent free conditions were the best conditions. All the synthesized compounds were screened for their antimicrobial activities. Antifungal and antibacterial activities of the synthesized compounds were evaluated against some Candida, filaments fungi, gram positive and gram negative bacteria by broth micro dilution method as recommended by CLSI. Results: The result showed that compounds A2, A3 and A4 against most of the tested Candida species and compounds A5 and A7 against C. parapsilosis and C. tropicalis, exhibited considerable antifungal activities. Also Compounds A8 and A10 showed desirable antifungal activities against C. neoformance and C. parapsilosis, respectively. The antibacterial activities of the synthesized compounds were also evaluated. Compounds A6 - A10 against E. Fecalis and compounds A5, A7, A9 and A10 against P. aeruginosa showed desirable antibacterial activities. Discussion: We have synthesized some new Mannich adducts of poly-hydroxyl phenols in the presence of nano-ZnO as a reusable catalyst, with the hope of discovering new lead compounds serving as potent antimicrobial agents. The advantages of this method are generality, high yields with short reaction times, simplicity, low cost and matching with green chemistry protocols. The antimicriobial studies of Mannich derivatives of phenols showed desirable results in vitro.

Hydrogen peroxide decomposition on a two-component CuO-Cr2O3 catalyst

1988 ◽  
Vol 53 (8) ◽  
pp. 1636-1646 ◽  
Author(s):  
Viliam Múčka ◽  
Kamil Lang
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Extreme Values ◽  
Catalytic Properties ◽  
Active Components ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Peroxide Decomposition ◽  
Two Component ◽  
Catalytically Active

Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalyst with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a testing reaction. It has been found that along to both basic components, the system under study contains also the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate is catalytically active. During the first period of the reaction the equilibrium is being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties are changed rather significantly after the thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably in connection with the changes of the valence state of the catalytically active components of the catalyst.

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