Effect of the Structure of Unsaturated Hydrocarbons and Alcohols on Their Reactivity and Adsorptivity in Hydrogenation

2000 ◽  
Vol 65 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Petr Kačer ◽  
Petr Novák ◽  
Libor Červený
Keyword(s):  
Double Bond ◽  
Supported Catalyst ◽  
Double Bond Position ◽  
Major Effect ◽  
Hydroxyl Group ◽  
Adsorption Parameters ◽  
Unsaturated Hydrocarbons ◽  
Unsaturated Alcohols ◽  
Group Position ◽  
Palladium Supported Catalyst

Competitive hydrogenations of unsaturated hydrocarbons and unsaturated alcohols using a palladium supported catalyst, were studied under atmospheric pressure at 25 °C. From the acquired data and from the hydrogenation of each individual substrate, kinetic and adsorption parameters were determined. It was found that the hydroxyl group position relative to the double bond has no significant effect on the reactivity of the studied unsaturated alcohols; however, it has a major effect on their adsorptivity. Reactivity and adsorptivity of unsaturated hydrocarbons depended on the double bond position in substrates.

Combinatorial Synthesis of Novel 9R-Acyloxyquinine Derivatives as Insecticidal Agents

2020 ◽  
Vol 23 (2) ◽  
pp. 111-118
Author(s):  
Zhiping Che ◽  
Jinming Yang ◽  
Di Sun ◽  
Yuee Tian ◽  
Shengming Liu ◽  
...  
Keyword(s):  
Natural Products ◽  
Double Bond ◽  
Insecticidal Activity ◽  
Structural Modification ◽  
Combinatorial Synthesis ◽  
Hydroxyl Group ◽  
Botanical Insecticide ◽  
Mythimna Separata ◽  
Lead Compounds

Background: It is one of the effective ways for pesticide innovation to develop new insecticides from natural products as lead compounds. Quinine, the main alkaloid in the bark of cinchona tree as well as in plants in the same genus, is recognized as a safe and potent botanical insecticide to many insects. The structural modification of quinine into 9R-acyloxyquinine derivatives is a potential approach for the development of novel insecticides, which showed more toxicity than quinine. However, there are no reports on the insecticidal activity of 9Racyloxyquinine derivatives to control Mythimna separata. Methods: Endeavor to discover biorational natural products-based insecticides, 20 novel 9Racyloxyquinine derivatives were prepared and assessed for their insecticidal activity against M. separata in vivo by the leaf-dipping method at 1 mg/mL. Results: Among all the compounds, especially derivatives 5i, 5k and 5t exhibited the best insecticidal activity with final mortality rates of 50.0%, 57.1%, and 53.6%, respectively. Conclusion: Overall, a free 9-hydroxyl group is not a prerequisite for insecticidal activity and C9- substitution is well tolerated; modification of out-ring double-bond is acceptable, and hydrogenation of double-bond enhances insecticidal activity; Quinine ring is essential and open of it is not acceptable. These preliminary results will pave the way for further modification of quinine in the development of potential new insecticides.

Highly selective palladium supported catalyst for hydrogenation of phenol in aqueous phase

2011 ◽  
Vol 12 (12) ◽  
pp. 1071-1074 ◽  
Author(s):  
Yolanda Pérez ◽  
Mariano Fajardo ◽  
Avelino Corma
Keyword(s):  
Aqueous Phase ◽  
Supported Catalyst ◽  
Palladium Supported Catalyst

Structural preferences for the double bond position in some unsaturated 3,3-diphenylpyrrolidines

1970 ◽  
Vol 48 (23) ◽  
pp. 3742-3745 ◽  
Author(s):  
M. M. A. Hassan ◽  
A. F. Casy
Keyword(s):  
Double Bond ◽  
Methyl Iodide ◽  
Quaternary Salt ◽  
Double Bond Position ◽  
Magnesium Bromide ◽  
Free Base ◽  
Spectroscopic Evidence ◽  
Structural Preferences ◽  
Ethyl Magnesium Bromide ◽  
Sole Product

The reaction between 3,3-diphenyl-3-cyano-1-methylpropyl isocyanate and ethyl magnesium bromide leads to 2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline rather than the isomeric 2-ethylidenepyrrolidine. The protonated N-methyl analogue (identical with a major metabolite of methadone) retains the 1-pyrroline structure, but the free base is a cis-trans mixture of the corresponding 2-ethylidenepyrrolidines; the cis Me/Ph isomer preponderates and is the sole product (obtained as a quaternary salt) when the mixture is treated with methyl iodide. 5-Methyl-2-methylene-3,3-diphenylpyrrolidine, a lower homologue of the methadone metabolite, isomerizes to a 1-pyrroline derivative when protonated or methylated. All structural conclusions are based on i.r. and p.m.r. spectroscopic evidence.

scholarly journals Interplay of Unsaturated Phospholipids and Cholesterol in Membranes: Effect of the Double-Bond Position

2008 ◽  
Vol 95 (7) ◽  
pp. 3295-3305 ◽  
Author(s):  
Hector Martinez-Seara ◽  
Tomasz Róg ◽  
Marta Pasenkiewicz-Gierula ◽  
Ilpo Vattulainen ◽  
Mikko Karttunen ◽  
...  
Keyword(s):  
Double Bond ◽  
Double Bond Position

Hydroxyproline adsorption on a mercury electrode in neutral solution

1991 ◽  
Vol 69 (10) ◽  
pp. 1528-1534 ◽  
Author(s):  
M. M. Gómez
Keyword(s):  
Dipole Moment ◽  
Adsorption Process ◽  
Normal Component ◽  
Mercury Electrode ◽  
Hydroxyl Group ◽  
Neutral Solution ◽  
Pyrrolidine Ring ◽  
Adsorption Parameters ◽  
Gibbs Energies ◽  
Comparison Of The Results

The adsorption of hydroxyproline (HPRO) on mercury in aqueous solutions of 10−2 M KClO4 has been determined from electrocapillary and capacity measurements. Comparison of the results obtained for HPRO with those reported for proline (PRO) shows that the presence of a hydroxyl group in the molecule has a small effect on the adsorption process. The respective values for adsorption parameters are −7 and −5 μC cm−2 for the charges of maximum adsorption, −13.0 and −10.4 kj mol−1 for the standard Gibbs energies of adsorption at zero charge, and −1.28 and +0.6 for the α parameter in the Frumkin isotherms. According to the analysis carried out for the normal component of the dipole moment of HPRO, −0.8 D, the more probable orientation of this aminoacid adsorbed on mercury is with the pyrrolidine ring parallel to the electrode surface resting the OH group away from the surface. Key words: adsorption, double layer, aminoacids, hydroxyproline.

Sign in / Sign up

Export Citation Format

Share Document