THE HYDROLYSIS OF PROPIONITRILE IN CONCENTRATED SOLUTIONS OF MINERAL ACIDS

1942 ◽  
Vol 20b (8) ◽  
pp. 168-173 ◽  
Author(s):  
J. D. McLean ◽  
B. S. Rabinovitch ◽  
C. A. Winkler
Keyword(s):  
Activation Energy ◽  
Sulphuric Acid ◽  
Acid Concentration ◽  
Rate Increase ◽  
Acid Solutions ◽  
Concentrated Solutions ◽  
Consecutive Reactions ◽  
Mineral Acids ◽  
Hydrolysis Of

The study of the hydrolysis of propionitrile in concentrated acid solutions has been extended to hydrobromic, nitric, and sulphuric acids for a range of acid concentrations. For the system of irreversible, unimolecular consecutive reactions, nitrile [Formula: see text] amide [Formula: see text] acid, [Formula: see text] for all acid concentrations below 4 N. At higher concentrations, k1 and k2 are of the same order, and, in the case of sulphuric acid, k1 becomes [Formula: see text]k2 at concentrations above 20 N. The observed activation energy decreases with increasing acid concentration for all acids. The specific differences in rate increase with acid concentration may be accounted for by the specific variations of A and E for each acid.

THE HYDROLYSIS OF ACID AMIDES IN CONCENTRATED HYDROCHLORIC ACID SOLUTIONS

1942 ◽  
Vol 20b (5) ◽  
pp. 73-81 ◽  
Author(s):  
B. S. Rabinovitch ◽  
C. A. Winkler
Keyword(s):  
Activation Energy ◽  
Hydrochloric Acid ◽  
Acid Concentration ◽  
Reaction Rates ◽  
Activation Energies ◽  
Acid Solutions ◽  
Hydrochloric Acid Solutions ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

The Arrhenius constants have been evaluated for the hydrolysis of formamide, acetamide, propionamide, and benzamide in hydrochloric acid solutions over the concentration range 1 to 10 N. There is approximate correspondence between reaction rates and activation energies for the series of amides. An increase in observed activation energy with increasing acid concentration was found for all amides. The maximum in rate of hydrolysis, which occurs at higher acid concentrations, is discussed and accounted for by the variation in the Arrhenius constants with acid concentration.

THE HYDROLYSIS OF PROPIONITRILE IN CONCENTRATED HYDROCHLORIC ACID SOLUTIONS

1942 ◽  
Vol 20b (7) ◽  
pp. 121-132 ◽  
Author(s):  
B. S. Rabinovitch ◽  
C. A. Winkler ◽  
A. R. P. Stewart
Keyword(s):  
Activation Energy ◽  
Hydrochloric Acid ◽  
Acid Concentration ◽  
Acid Solutions ◽  
Large Measure ◽  
Unimolecular Reactions ◽  
Hydrochloric Acid Solutions ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Ammonia Formation

The hydrolysis of propionitrile has been studied in aqueous hydrochloric acid solutions from 0.5 to 10 N and over a range of temperatures at six acid concentrations. The rate of hydrolysis as measured by ammonia formation is dependent upon the decomposition of the intermediate amide at acid concentrations above 4 N. The system represented by nitrile [Formula: see text] amide [Formula: see text] acid affords a good example of consecutive, irreversible unimolecular reactions over the complete range [Formula: see text] (below 4 N) to [Formula: see text] (above 11 N). A marked increase in rate with increasing acid concentration is accounted for in large measure by a decrease in observed activation energy of 6.7 Cal. over the range 1 to 10 N.

THE HYDROLYSIS OF ALIPHATIC NITRILES IN CONCENTRATED HYDROCHLORIC ACID SOLUTIONS

1942 ◽  
Vol 20b (10) ◽  
pp. 221-230 ◽  
Author(s):  
B. S. Rabinovitch ◽  
C. A. Winkler
Keyword(s):  
Activation Energy ◽  
Hydrochloric Acid ◽  
Acid Concentration ◽  
Hydrocyanic Acid ◽  
Acid Solutions ◽  
Acid Media ◽  
Hydrochloric Acid Solutions ◽  
Aliphatic Nitriles ◽  
Nitrile Hydrolysis ◽  
Hydrolysis Of

Studies of nitrile hydrolysis in concentrated acid media have been extended to the hydrolysis of hydrocyanic acid, acetonitrile, and cyanoacetic acid in hydrochloric acid solutions of concentration 1 to 8.5 N. It appears that the hydrolysis of aliphatic nitriles in concentrated sulphuric and hydrochloric acids provides systems of consecutive, irreversible unimolecular reactions over the complete range knitrile[Formula: see text]kamide (more dilute acid) to knitrile[Formula: see text]kamide (highly concentrated acid), for a sufficient range of acid concentrations. The limit, knitrile[Formula: see text]kamide, is not attained in hydrobromic acid solutions. The nitriles studied here exhibit a large decrease in activation energy with increase of acid concentration, similar to that observed earlier for propionitrile. The magnitude of the variation of the Arrhenius parameters is specific for each nitrile. For the acetonitrile hydrolysis, the increase in rate with increase of acid concentration largely follows the accompanying activation energy decrease. The relative rates of hydrolysis of different nitriles, at given acid concentration, are not governed by differences in activation energy. The variation of activation energy is briefly discussed in relation to certain other factors.

THE RAMAN SPECTRUM OF THE SULPHURIC ACIDIUM ION: THE CONSTITUTION OF CONCENTRATED SOLUTIONS OF TETRA(HYDROGENSULPHATO)BORIC ACID IN SULPHURIC ACID

1962 ◽  
Vol 40 (4) ◽  
pp. 784-787 ◽  
Author(s):  
R. J. Gillespie ◽  
E. A. Robinson
Keyword(s):  
Raman Spectrum ◽  
Boric Acid ◽  
Sulphuric Acid ◽  
Raman Spectra ◽  
Acid Solutions ◽  
Concentrated Solutions

The Raman spectra of sulphuric acid solutions of tetra(hydrogensulphato)boric acid and its sodium and hydronium salts have been examined. Frequencies are assigned to some of the vibrations of the sulphuric acidium ion, H3SO4+, and are compared with the frequencies of the analogous vibrations of H2SO4 and HSO4−. Evidence is presented that elimination of disulphuric acid occurs between molecules of HB(HSO4)4 to give polymers containing B—O—B linkages.

scholarly journals Phase Behaviour of Cellulose Nanocrystal Dispersion in Aqueous Sulphuric Acid and Development of an Energy Efficient Separation Technique for the Acid-Cellulose Nanocrystal System

2017 ◽  
Vol 371 ◽  
pp. 59-72
Author(s):  
Soon Yee Liew ◽  
Wim Thielemans ◽  
Buddhika Hewakandamby
Keyword(s):  
Sulphuric Acid ◽  
Energy Efficient ◽  
Volume Fraction ◽  
Extraction Process ◽  
Phase Behaviour ◽  
Cellulose Nanocrystal ◽  
Separation Mechanism ◽  
Acid Solutions ◽  
Efficient Separation ◽  
Hydrolysis Of

In this paper, the phase behaviour of a cellulose nanocrystal (CNCs) dispersion in sulphuric acid solutions was investigated, aimed at the development of an energy efficient separation method for this mixture. The system in consideration was a mixture of 30 wt% aqueous sulphuric acid (ρl = 1219 kg/m3) containing 12.6 mg/ml of cellulose nanocrystals (CNCs) (ρs = 1590 kg/m3, volume fraction of CNCs less than 1%). This volume filling mixture was obtained directly from a CNC extraction process, as obtained after the hydrolysis of cotton using 64 wt% sulphuric acid at ca. 45 ̊C for 45 minutes (this condition was required for the extraction of CNCs from cotton) followed by quenching the hydrolysis with water. The CNCs form the desired product and need to be separated from the acid that can then be recycled. Conventionally this separation has been difficult and requires a large input of energy. This work addresses this problem by investigating into the phase behaviour and physicochemical and hydrodynamic character of this mixture. This understanding led to the development of a very energy efficient separation mechanism for this mixture, which is 5 orders of magnitude more energy efficient than the most widely used centrifugation systems.

The Hydrolysis of Hydrogen Cyanide in Acetic Acid Solutions with Mineral Acids as Catalysts1

1943 ◽  
Vol 65 (8) ◽  
pp. 1479-1482
Author(s):  
Vernon K. Krieble ◽  
Frederick C. Duennebier ◽  
Edward Colton
Keyword(s):  
Acetic Acid ◽  
Hydrogen Cyanide ◽  
Acid Solutions ◽  
Mineral Acids ◽  
Hydrolysis Of

scholarly journals Studies of the processes operative in solutions. XXII.—The hydrolysis of cane sugar by Sulphuric acid; also a note on improvements in Polarimetric apparatus

1912 ◽  
Vol 87 (599) ◽  
pp. 563-581
Keyword(s):  
Sulphuric Acid ◽  
Dibasic Acid ◽  
Hydrolytic Activity ◽  
Cane Sugar ◽  
Gradual Change ◽  
Concentrated Solutions ◽  
Degree Of Hydration ◽  
Series Of Experiments ◽  
Hydrolysis Of ◽  
Angle Of Rotation

In view of the fact that the acids used in the inquiries discussed in Part XII and the succeeding parts of these studies were all monobasic, it was desirable to investigate the hydrolytic activity of a dibasic acid, more especially with a view to following the progressive alteration in molecular hydrolytic activity and apparent degree of hydration attending changes of concentration. A series of experiments, using sulphuric acid as the catalyst, has been carried out therefore on the lines of those described in Part XII. Some of the complexities of the hydrolytic process and of the polarimetric method of following its course were dealt with in that communication; moreover, several disturbing factors were referred to, such as the change in the osmotic conditions as the action proceeds and changes in the optical activity of the various substances due to dilution, to their mutual interference, and to the influence of acids or salts; the possible influence of “mutarotation,” however, was not mentioned, as there appeared to be no reason to believe that it in any way affected the results. The study of the rates at which hydrolysis is effected by sulphuric acid of different degrees of concentration has shown that exactly the same complexities are met with in this case as were experienced in the case of chlorhydric and nitric acids. Thus, in the more concentrated solutions, there is a gradual change in the final angle of rotation after hydrolysis is complete such as was observed in the inquiry described in Part XII; this was allowed for as before when necessary, though in most of the experiments the concentration was not great enough for its effect to be noticed.

THE BEHAVIOR OF LEAD ELECTRODES IN SULPHURIC ACID SOLUTIONS

1964 ◽  
Vol 42 (6) ◽  
pp. 1355-1364 ◽  
Author(s):  
K. Ekler
Keyword(s):  
Sulphuric Acid ◽  
Acid Concentration ◽  
Current Density ◽  
The Self ◽  
Acid Solutions ◽  
Time Data ◽  
Passivation Time ◽  
Lead Electrodes ◽  
Passivation Potential

Lead electrodes were anodically etched in NH2SO3H. Immersion potentials, self-passivation potentials, passivation times, PbO2/O2 potential, and the potential of the first discharge plateau were determined in H2SO4 solutions ranging from 0.5 to 20.0 N and were found to be concentration-dependent. Interruption of the anodizing current had no detectable influence on passivation time. Data obtained with the anodizing current turned on fall into three categories; those obtained with (1) short-immersion anodes, (2) anodes which had reached a hydrogen-like potential, and (3) anodes which were self-passivated before the current was switched on. An inflection in the relation between potential and time during charging was investigated. Its length was dependent upon acid concentration and current density, while its potential was +300 ± 30 mv, and seemed to correspond to the self-passivation potential. The lengths of the first and second discharge plateaus increased with the number of coulombs passed and were dependent upon acid concentration, but were identical for electrodes treated by four different methods. The hydrogen-like potential appeared to be due to the presence of PbO•PbSO4. The self-passivation potential seemed to be caused by formation of PbO.

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