DFT study of phenol alkylation with propylene on H-BEA in the absence and presence of water

2021 ◽  
Author(s):  
Sajal Kanti Dutta ◽  
Vishal Agarwal
Keyword(s):  
Transition State ◽  
Transition State Theory ◽  
Rate Coefficient ◽  
Activation Barrier ◽  
State Theory ◽  
Dft Study ◽  
Phenol Alkylation ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

Water reduces the activation barrier of the rate-limiting step of phenol alkylation with propylene in H-BEA. This, in turn, increases the transition-state theory rate coefficient by two orders-of-magnitude, suggesting much faster alkylation.

Biological treatability of a corn wet mill effluent

2002 ◽  
Vol 45 (12) ◽  
pp. 339-346 ◽  
Author(s):  
G. Eremektar ◽  
O. Karahan-Gul ◽  
F. Germirli-Babuna ◽  
S. Ovez ◽  
H. Uner ◽  
...  
Keyword(s):  
Biological Treatment ◽  
Rate Coefficient ◽  
Activated Sludge Process ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Metabolic Products ◽  
High Level ◽  
Biological Treatability ◽  
Rate Limiting ◽  
Hydrolysis Of

Corn wet mill effluents are studied in terms of their characteristics relevant for biological treatment. They have a high COD of mainly soluble and biodegradable nature, with practically no soluble inert components. They generate a relatively high level of soluble residual metabolic products, which affects the choice of the appropriate biological treatment and favors aerobic activated sludge process. Experimental assessment of process kinetics yields typical values. Hydrolysis of the slowly biodegradable COD, the rate limiting step for the utilization of substrate, is characterized by an overall rate coefficient, which is within the range commonly associated for the hydrolysis of starch.

Transition State of the Rate-Limiting Step of Heat Denaturation of Cry3A δ-Endotoxin†

Biochemistry ◽  
1999 ◽  
Vol 38 (13) ◽  
pp. 4121-4127 ◽  
Author(s):  
Sergey A. Potekhin ◽  
Olga I. Loseva ◽  
Elizabeth I. Tiktopulo ◽  
Anatoly P. Dobritsa
Keyword(s):  
Transition State ◽  
Heat Denaturation ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

Transition state theory for ion-molecule reactions

1978 ◽  
Vol 360 (1700) ◽  
pp. 1-23 ◽  
Keyword(s):  
Transition State ◽  
Transition State Theory ◽  
Rate Coefficient ◽  
State Theory ◽  
Initial Slope ◽  
Orbital Energy ◽  
Helium Pressure ◽  
Ion Molecule Reactions ◽  
Radiative Association ◽  
Saturation Region

The standard formula for the rate coefficient given by transition state theory is not valid for exothermic ion-molecule reactions having no activation energy. A formula covering these is derived. For monatomic reactants Langevin’s formula is recovered. In the general case, account must be taken of the long-lived collision complex which arises because of the transfer of orbital energy into the rotational and vibrational modes of the reactants. The theory is applied to bimolecular reactions (most of which it gives to be rapid whether or not an electronic transition is involved), to termolecular association and to radiative association. The major conflict with experiment concerns N 2 + N 2 + + He---- >N 4 + + He which Bohme, Dunkin, Fehsenfeld & Ferguson (1968) have studied at a temperature of 80 K. According to their measurements, the apparent binary rate coefficient is a linear function of the helium pressure, if this is low, but above about a torr it reaches a saturation limit of only around one hundredth of the Langevin rate coefficient, the transition from the linear to the saturation region being quite sharp. Only the initial slope is in agreement with expectation.

Ornithine Decarboxylase Activity in Cultured Endothelial Cells Stimulated by Serum, Thrombin and Serotonin

1978 ◽  
Vol 39 (02) ◽  
pp. 496-503 ◽  
Author(s):  
P A D’Amore ◽  
H B Hechtman ◽  
D Shepro
Keyword(s):  
Endothelial Cells ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Aortic Endothelial Cells ◽  
Ornithine Decarboxylase Activity ◽  
Rate Limiting Step ◽  
Bovine Aortic Endothelial Cells ◽  
Limiting Step ◽  
Rate Limiting ◽  
Serum Serotonin

SummaryOrnithine decarboxylase (ODC) activity, the rate-limiting step in the synthesis of polyamines, can be demonstrated in cultured, bovine, aortic endothelial cells (EC). Serum, serotonin and thrombin produce a rise in ODC activity. The serotonin-induced ODC activity is significantly blocked by imipramine (10-5 M) or Lilly 11 0140 (10-6M). Preincubation of EC with these blockers together almost completely depresses the 5-HT-stimulated ODC activity. These observations suggest a manner by which platelets may maintain EC structural and metabolic soundness.

Dynamics of hepatic and peripheral insulin effects suggest common rate-limiting step in vivo

Diabetes ◽  
1993 ◽  
Vol 42 (2) ◽  
pp. 296-306 ◽  
Author(s):  
D. C. Bradley ◽  
R. A. Poulin ◽  
R. N. Bergman
Keyword(s):  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting
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