Chemical Activation and Nonequilibrium Unimolecular Reactions of C2H5Cl and 1,2‐C2H4Cl2 Molecules

1966 ◽  
Vol 45 (9) ◽  
pp. 3231-3236 ◽  
Author(s):  
J. C. Hassler ◽  
D. W. Setser ◽  
R. L. Johnson
Keyword(s):  
Chemical Activation ◽  
Unimolecular Reactions

Chemical Activation Study of the Unimolecular Reactions of CD3CD2CHCl2 and CHCl2CHCl2 with Analysis of the 1,1-HCl Elimination Pathway

2016 ◽  
Vol 120 (42) ◽  
pp. 8244-8253 ◽  
Author(s):  
Allie C. Larkin ◽  
Matthew J. Nestler ◽  
Caleb A. Smith ◽  
George L. Heard ◽  
D. W. Setser ◽  
...  
Keyword(s):  
Chemical Activation ◽  
Unimolecular Reactions ◽  
Elimination Pathway

Photochemical studies of unimolecular processes IV. Quenching of vibrationally excited cycloheptatriene by added gases

1972 ◽  
Vol 329 (1577) ◽  
pp. 233-240 ◽  
Keyword(s):  
Chemical Activation ◽  
Vibrationally Excited ◽  
Unimolecular Reactions

The relaxation of highly vibrationally excited cycloheptatriene molecules by a variety -of added gases has been studied photochemically. The following mean energies removed per downward step were deduced; He, 1.8; No, 2.4; Ar, 3.5; Kr, 3.6; Xe, 3.3; H 2 , 2.6; D 2 , 2.4; n-C 5 H 12 , 11.7; neo-C 5 H 12 , 10.2 kJ mol -1 . These agree better with data from the ‘fall off’ of unimolecular reactions than with chemical activation studies.

Introduction

1996 ◽  
Author(s):  
Tomas Baer ◽  
William L. Hase
Keyword(s):  
Internal Energy ◽  
Vibrational Energy ◽  
Chemical Activation ◽  
Experimental Studies ◽  
Spectroscopic Studies ◽  
Dissociation Limit ◽  
Major Advance ◽  
Thermal Systems ◽  
Unimolecular Reactions ◽  
Intramolecular Vibrational Energy Redistribution

The field of unimolecular reactions has witnessed impressive advances in both experimental and theoretical techniques during the past 20 years. These developments have resulted in experimental measurements that finally permit critical tests of the major assumptions made more than 60 years ago when Rice and Ramsperger (1927, 1928) and Kassel (1928) first proposed their statistical RRK theory of unimolecular decay. At the heart of these advances is our ability to prepare molecules in narrow ranges of internal energy, even in single quantum states, at energies below and above the dissociation limit. This has led to detailed spectroscopic studies of intramolecular vibrational energy redistribution (IVR), a process that is intimately related to the assumption of random energy flow in the statistical theory of unimolecular decay. This book is devoted exclusively to the study of state- or energy-selected systems. However, in order to place these studies in the context of the much larger field of unimolecular reactions in general, we provide a brief background of the field up to about 1970. The experimental studies of unimolecular reactions developed in three stages. The early studies involved strictly thermal systems in which molecules were energized by heating the sample either in a bulb (Chambers and Kistiakowsky, 1934; Schlag and Rabinovitch, 1960; Flowers and Frey, 1962; Schneider and Rabinovitch, 1962), or by more sophisticated methods such as shock tubes which were applied to unimolecular reactions by Tsang (1965, 1972, 1978, 1981) and others (Astholz et al., 1979; Brouwer et al.,1983). The drawback of these studies is that molecules were prepared in a very broad (albeit well characterized) distribution of internal energy states. A major advance was the use of chemical activation in the early 1960s in which a species such as CH2 reacted with a molecule, thereby forming an energized species which could either isomerize or be stabilized by collisions (Rabinovitch and Flowers, 1964; Rabinovitch and Setser, 1964; Kirk et al., 1968; Hassler and Setser, 1966; Simons and Taylor, 1969). This approach permitted the reacting species to be prepared in a narrow range of internal energies.

Activated carbon from molasses efficiency for Cr(VI), Pb(II) and Cu(II) adsorption: A mechanistic study

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Activated Carbon ◽  
Phosphoric Acid ◽  
Sugar Industry ◽  
Chemical Activation ◽  
High Surface ◽  
High Surface Area ◽  
Mechanistic Study ◽  
Acid Mixture ◽  
Maximum Adsorption Capacity ◽  
Good Potential

Activated carbon was prepared from molasses, which are natural precursors of vegetable origin resulting from the sugar industry. A simple elaboration process, based on chemical activation with phosphoric acid, was proposed. The final product, prepared by activation of molasses/phosphoric acid mixture in air at 500°C, presented high surface area (more than 1400 m2/g) and important maximum adsorption capacity for methylene blue (625 mg/g) and iodine (1660 mg/g). The activated carbon (MP2(500)) showed a good potential for the adsorption of Cr(VI), Cu(II) and Pb(II) from aqueous solutions. The affinity for the three ions was observed in the following order Cu2+ Cr6+ Pb2+. The process is governed by monolayer adsorption following the Langmuir model, with a correlation coefficient close to unity.

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