نتایج جستجو برای: catalytic effects

تعداد نتایج: 1616125  

Journal: :Pharmacological reviews 2000
L Q Sun M J Cairns E G Saravolac A Baker W L Gerlach

Since the discovery of self-cleavage and ligation activity of the group I intron, the expansion of research interest in catalytic nucleic acids has provided a valuable nonprotein resource for manipulating biomolecules. Although a multitude of reactions can be enhanced by this class of catalyst, including trans-splicing activity of the group I intron (which could be applied to gene correction), ...

Journal: :journal of sciences islamic republic of iran 0

three high-silica mordenite zeolites differing in sio440, ratio were prepared by direct synthesis without using any template. the products si02/a120, ratio is influenced by the starting gel composition. this ratio is increased upon ion-exchange with nh,cl and subsequent calcination to prepare protonic mordenite. the protonic mordenites with si02/a1203ra tios of 14.6,29.2 and 34.6 were character...

Journal: :iranian journal of catalysis 2014
mohammad a. nasseri ali allahresani heidar raissi

nano-graphene oxide was synthesized by the oxidation of graphite powders. the structural nature of the nano-graphene oxide was characterized by a variety of techniques including xrd, tem, ft-ir and uv/vis. the functional groups on its basal planes and edges of nano-grahene oxide play important role in catalytic activity. the catalytic activity of nano-graphene oxide was investigated on crossed-...

Journal: :journal of the iranian chemical research 0
yacine benguerba laboratoire de génie des procédés chimiques, université ferhat abbas sétif, 19000, sétif, algérie brahim djellouli laboratoire de génie des procédés chimiques, université ferhat abbas sétif, 19000, sétif, algérie lemnouer chibane laboratoire de génie des procédés chimiques, université ferhat abbas sétif, 19000, sétif, algérie lahcene bencheikh laboratoire de génie des procédés chimiques, université ferhat abbas sétif, 19000, sétif, algérie

the determination of the optimal distribution of the catalytic activity profile, whichmaximizes the catalytic effectiveness, in created unsteady state conditions, is analyzed andtreated numerically for the case of a simple reaction. it was proven that the modulation, of thetemperature and the reactant concentration of the external bulk fluid, leads to a considerableincrease of the catalytic eff...

Journal: :journal of physical & theoretical chemistry 2013
f. shams s. r. emamian e. zahedi

in the present work, impact of lewis acid (la) catalysts bf3, bcl3, and bbr3 on the kinetics andregioselectivity of 1,3-dipolar cycloaddition (1,3-dc) reaction between azidobenzene and acroleinwas theoretically studied using b3lyp/6-31g* level. our results indicate while the uncatalyzed 1,3-dc reaction under investigation takes place via a non-polar, non-regioselective, and lowasynchronous proc...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2013
babak salamatinia iman hashemizadeh abdullah ahmad zuhairi

four different alkaline earth metal oxides i.e. mgo, cao, sro and bao were used as heterogeneous catalysts for biodiesel production from palm oil. effects of critical process variables i.e. reaction time, methanol to oil ratio and temperature were investigated. the results were then fitted to a historical design to study the analysis of variance (anova), to characterize interactions between var...

1999
DONALD A. DAWSON Donald A. Dawson Klaus Fleischmann

In this paper we present an overview of recent work on lattice and measure-valued models of catalytic reactions and in particular catalytic branching systems. The main phenomena exhibited by nearly critical branching systems are dimension-dependent clumping in small and large space and time scales. Special emphasis is given to the e ects which occur when the catalyst is highly clumped and in pa...

2003
MARCEL DEKKER Shi-gang Zhang Heng Jiang Hong Gong Zhao-lin Sun

Synthesis of adipic acid by catalytic oxidation of cyclohexanone with 30% hydrogen peroxide in the presence of sodium tungstate catalyst can be well performed under reflux temperature. The adipic acid isolated yield reaches to 82.1%, and the purity of the product is also very high. The catalytic oxidation reaction takes place without any organic solvent and phase-transfer agent. The effects ove...

2014
Leqin He Shenjun Qin Tao Chang Yuzhuang Sun Jiquan Zhao

Quaternary ammonium geminal Brønsted acid ionic liquids (GBAILs) based on zwitterionic 1,2-bis[N-methyl-N-(3-sulfopropyl)-alkylammonium]ethane (where the carbon number of the alkyl chain is 4, 8, 10, 12, 14, 16, or 18) and p-toluenesulfonic acid monohydrate were synthesized. The catalytic ionic liquids were applied in three-component Mannich reactions with an aldehyde, ketone, and amine at 25 °...

Journal: :Molecules 2017
Pengyu Li Shanshan Du Yang Li Junlin He

In the 15-mer catalytic core of 10-23 DNAzyme, each residue contributes to the catalytic conformation differently. Here, the critically conserved T4 and the least conserved T8 were modified on their 5-position with hydroxyl, imidazolyl, and amino groups with a hydrogen-bonding ability. These external functional groups induced new interactions within the catalytic core, resulting in both negativ...

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