MOLECULAR ATTRACTIVE FORCES AND THE VELOCITY OF CHEMICAL REACTIONS

1930 ◽  
Vol 3 (6) ◽  
pp. 526-539 ◽  
Author(s):  
C. C. Coffin ◽  
O. Maass
Keyword(s):  
Atmospheric Pressure ◽  
Liquid State ◽  
Freezing Point ◽  
Effect Of Temperature ◽  
Molecular Compound ◽  
Reaction Products ◽  
Compound Formation ◽  
Gaseous State ◽  
Reaction Velocity ◽  
Molecular Attraction

The reactions between hydrogen chloride and α-, β-, and γ-butylene have been investigated in both the liquid and gaseous states. The effect of temperature and concentration of the reactants on the reaction velocities was studied and the reaction products were examined. In the liquid state the γ-isomer reacts rapidly, the α- much more slowly and the β- slowest of all. In the gaseous state at atmospheric pressure only γ-butylene shows a measurable reaction which is bimolecular and probably heterogeneous. The liquid reactions were found to be homogeneous. Where possible the freezing-point curves of the systems were determined in order to ascertain the extent of molecular compound formation. The results obtained bear out the conclusions arrived at from previous work on the effect of molecular attraction upon reaction velocity, and indicate the existence of a catalytic factor peculiar to the liquid state. Suggestions as to the mechanism of such a catalysis are offered.

NOTE ON SOLID-LIQUID EQUILIBRIA IN SOME TWO-COMPONENT SYSTEMS INVOLVING HYDROGEN CYANIDE

1933 ◽  
Vol 8 (2) ◽  
pp. 114-118 ◽  
Author(s):  
A. L. Peiker ◽  
C. C. Coffin
Keyword(s):  
Hydrogen Cyanide ◽  
Freezing Point ◽  
Eutectic Type ◽  
Molecular Compound ◽  
Compound Formation ◽  
Component Systems ◽  
Two Component ◽  
Hydride Hydrogen ◽  
Two Component Systems ◽  
Solid Liquid

The freezing-point curves of the two-component systems hydrogen cyanide-water, hydrogen cyanide-formic acid, hydrogen cyanide-formamide and hydrogen cyanide-benzaldehyde have been determined. These systems are all of the simple eutectic type and show no evidence of molecular compound formation. A chemical reaction prohibited the investigation of solid-liquid equilibria in the case of halogen hydride-hydrogen cyanide systems.

scholarly journals The effect of pressure on reactions in solution I—Sodium ethoxide and ethyl iodide to 3000 kg/cm 2 II—Pyridine and ethyl iodide to 8500 kg/cm 2

1935 ◽  
Vol 150 (869) ◽  
pp. 223-240 ◽  
Keyword(s):  
Atmospheric Pressure ◽  
Pressure Effect ◽  
Sodium Ethoxide ◽  
Ethyl Iodide ◽  
Effect Of Temperature ◽  
Reaction Velocity ◽  
Velocity Constant ◽  
Effect Of Pressure ◽  
Different Temperatures ◽  
Arrhenius Expression

Previous work has shown that pressure has an accelerating effect on a large number of chemical reactions in the liquid phase. The rates of the reaction between pyridine and cetyl halides have been studied at different temperatures and pressures, but it was not found possible to interpret the results by means of the ordinary reaction velocity equations, and no conclusions could be drawn as to the mechanism of the pressure effect. In making a further attempt to determine this mechanism, it seemed desirable to take reactions which have already been studied at atmospheric pressure and are known to follow the simple velocity equations, and to investigate the effect of pressure on the velocity con­stants. The effect of temperature on the velocity constant of a reaction k , can be expressed by the Arrhenius expression k = A e -E/RT . A knowledge of the variation of the velocity constant with pressure at different temperatures would show whether this change is due to a change in the value of the constants A or E, or of both.

SOME FREEZING POINT AND CONDUCTANCE MEASUREMENTS IN THE SYSTEM NITRIC ACID – ACETIC ACID

1951 ◽  
Vol 29 (6) ◽  
pp. 461-468 ◽  
Author(s):  
Edward G. Taylor ◽  
Alan G. Follows
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Freezing Point ◽  
Preliminary Investigation ◽  
Liquid System ◽  
Molecular Compound ◽  
Compound Formation ◽  
Vapor Equilibrium ◽  
Binary Azeotrope ◽  
Solid Liquid

An independent investigation of the phase diagram for the solid–liquid system nitric, acid – acetic acid has confirmed the findings of Miskidzh'yan and Trifonov (4), namely, that a 1: 1 molecular compound exists. Conductance measurements at 0°, 25°, and 40°C. have been made for the same system. It does not appear possible to predict compound formation from the conductance measurements alone. A preliminary investigation of the liquid–vapor equilibrium for the system nitric acid – acetic acid indicates the existence of a maximum boiling azeotrope. Diacetylorthonitric acid—(CH3COO)2N(OH)3—discovered by Pictet and Genequaud (8) is, in all probability, identical with this binary azeotrope. Some molecular weight measurements tend to confirm this view.

AN INVESTIGATION OF THE HYDROGEN-CHLORIDE-PROPYLENE REACTION IN THE REGION OF THE CRITICAL TEMPERATURE

1938 ◽  
Vol 16b (12) ◽  
pp. 453-467 ◽  
Author(s):  
C. H. Holder ◽  
O. Maass
Keyword(s):  
Critical Temperature ◽  
Temperature Coefficient ◽  
Hydrogen Chloride ◽  
Liquid State ◽  
Critical Density ◽  
Positive Temperature ◽  
Gaseous State ◽  
Gaseous Mixtures ◽  
Reaction Velocity ◽  
Temperature Range

The reaction between hydrogen chloride and propylene has been studied in the gaseous state above the critical temperature and in the liquid state just below the critical temperature. Pressures were used such that the density of the gaseous mixtures could be made as great as the density of the liquid mixture at some temperature.The rate of reaction above the critical temperature increases slowly with increasing pressure until a certain critical density is attained, after which the rate increases rapidly. In the liquid state the reaction has a positive temperature coefficient except for a 25° temperature range just below the critical temperature. In this region there is a rapid decrease in density of the medium with rise in temperature and a negative temperature coefficient occurs.The density of the liquid reactants at a number of temperatures just below the critical temperature (here defined as the temperature where the visible meniscus disappears) has been reproduced above the critical temperature for a small temperature range. The reaction velocity data obtained under these conditions show a minimum in passing through the critical temperature region.The above results have been interpreted on the basis of a "structure" characteristic of the liquid state which favors higher reaction velocity and which may exist above the critical temperature at sufficiently high densities.

Kinetics of the catalytic hydrodesulphurization reaction system; hydrogenolysis of thiophene

1980 ◽  
Vol 45 (10) ◽  
pp. 2728-2741 ◽  
Author(s):  
Pavel Fott ◽  
Petr Schneider
Keyword(s):  
Atmospheric Pressure ◽  
Active Sites ◽  
Flow Reactor ◽  
Kinetic Equations ◽  
Reaction System ◽  
Reaction Products ◽  
Molybdenum Catalyst ◽  
Cobalt Molybdenum Catalyst ◽  
Kinetics Of ◽  
Reaction Schemes

Kinetics have been studied of the reaction system taking place during the reaction of thiophene on the cobalt-molybdenum catalyst in a gradientless circulation flow reactor at 360 °C and atmospheric pressure. Butane has been found present in a small amount in the reaction products even at very low conversion. In view of this, consecutive and parallel-consecutive (triangular) reaction schemes have been proposed. In the former scheme the appearance of butane is accounted for by rate of desorption of butene being comparable with the rate of its hydrogenation. According to the latter scheme part of the butane originates from thiophene via a different route than through hydrogenation of butene. Analysis of the kinetic data has revealed that the reaction of thiophene should be considered to take place on other active sites than that of butene. Kinetic equations derived on this assumption for the consecutive and the triangular reaction schemes correlate experimental data with acceptable accuracy.

Heat capacities of liquid 2,3,6-trimethylpyridine, 2,4,6-trimethylpyridine and 3-methoxypropionitrile within the range of temperatures of 300 to 328 K

1991 ◽  
Vol 56 (12) ◽  
pp. 2786-2790 ◽  
Author(s):  
Václav Svoboda ◽  
Milan Zábranský
Keyword(s):  
Temperature Interval ◽  
Atmospheric Pressure ◽  
Liquid State ◽  
Adiabatic Calorimeter ◽  
Heat Capacities

Molar heat capacities of 2,3,6-trimethylpyridine, 2,4,6-trimethylpyridine and 3-methoxypropionitrile in the liquid state were measured at the constant atmospheric pressure in the temperature interval of 300.60 to 328.35 K. The static type of adiabatic calorimeter was used for the measurements.

scholarly journals Cloud Particles Differential Evolution Algorithm: A Novel Optimization Method for Global Numerical Optimization

2015 ◽  
Vol 2015 ◽  
pp. 1-36 ◽  
Author(s):  
Wei Li ◽  
Lei Wang ◽  
Quanzhu Yao ◽  
Qiaoyong Jiang ◽  
Lei Yu ◽  
...  
Keyword(s):  
Solid State ◽  
Differential Evolution ◽  
Liquid State ◽  
Differential Evolution Algorithm ◽  
Optimization Method ◽  
Benchmark Problems ◽  
Gaseous State ◽  
Mutation Strategy ◽  
Evolution Algorithm ◽  
Cloud Particles

We propose a new optimization algorithm inspired by the formation and change of the cloud in nature, referred to as Cloud Particles Differential Evolution (CPDE) algorithm. The cloud is assumed to have three states in the proposed algorithm. Gaseous state represents the global exploration. Liquid state represents the intermediate process from the global exploration to the local exploitation. Solid state represents the local exploitation. The best solution found so far acts as a nucleus. In gaseous state, the nucleus leads the population to explore by condensation operation. In liquid state, cloud particles carry out macrolocal exploitation by liquefaction operation. A new mutation strategy called cloud differential mutation is introduced in order to solve a problem that the misleading effect of a nucleus may cause the premature convergence. In solid state, cloud particles carry out microlocal exploitation by solidification operation. The effectiveness of the algorithm is validated upon different benchmark problems. The results have been compared with eight well-known optimization algorithms. The statistical analysis on performance evaluation of the different algorithms on 10 benchmark functions and CEC2013 problems indicates that CPDE attains good performance.

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