The protonation of weak bases. A study of the protonation of some nitroaniline indicators and the determination of the H 0 values of aqueous sulphuric acid

1970 ◽  
pp. 65 ◽  
Author(s):  
P. Tickle ◽  
A. G. Briggs ◽  
J. M. Wilson
Keyword(s):  
Sulphuric Acid ◽  
Weak Bases

scholarly journals Modelling and Multi-Objective Optimization of the Sulphur Dioxide Oxidation Process

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1072
Author(s):  
Mohammad Reza Zaker ◽  
Clémence Fauteux-Lefebvre ◽  
Jules Thibault
Keyword(s):  
Sulphuric Acid ◽  
Sulphur Dioxide ◽  
Variable Number ◽  
Inlet Temperature ◽  
Multi Objective Optimization ◽  
Absorption Column ◽  
Maximum Reaction Rate ◽  
Multi Objective ◽  
Maximum Reaction

Sulphuric acid (H2SO4) is one of the most produced chemicals in the world. The critical step of the sulphuric acid production is the oxidation of sulphur dioxide (SO2) to sulphur trioxide (SO3) which takes place in a multi catalytic bed reactor. In this study, a representative kinetic rate equation was rigorously selected to develop a mathematical model to perform the multi-objective optimization (MOO) of the reactor. The objectives of the MOO were the SO2 conversion, SO3 productivity, and catalyst weight, whereas the decisions variables were the inlet temperature and the length of each catalytic bed. MOO studies were performed for various design scenarios involving a variable number of catalytic beds and different reactor configurations. The MOO process was mainly comprised of two steps: (1) the determination of Pareto domain via the determination a large number of non-dominated solutions, and (2) the ranking of the Pareto-optimal solutions based on preferences of a decision maker. Results show that a reactor comprised of four catalytic beds with an intermediate absorption column provides higher SO2 conversion, marginally superior to four catalytic beds without an intermediate SO3 absorption column. Both scenarios are close to the ideal optimum, where the reactor temperature would be adjusted to always be at the maximum reaction rate. Results clearly highlight the compromise existing between conversion, productivity and catalyst weight.

VI. The glucoside constitution of proteid matter

1894 ◽  
Vol 54 (326-330) ◽  
pp. 53-57 ◽  
Keyword(s):  
Sulphuric Acid ◽  
Cupric Oxide ◽  
The Body ◽  
Long Time

For a long time I have adopted a process for separating the glycogen of the liver consisting in boiling with potash, pouring into alcohol, and collecting the precipitate. For the purpose of estimation, the precipitated glycogen was converted by means of sulphuric acid into glucose, the determination of which gave the information required. I afterwards applied the process to blood, and the various organs and tissues of the body, with the result that a more or less notable amount of cupric oxide reducing product was obtained, which I at the time looked upon as taking origin, as in the case of the liver, from glycogen.

NEW COLOR REACTIONS OF SEDOHEPTULOSAN AND ITS DETERMINATION IN MIXTURES OF RIBOSE AND FRUCTOSE

1954 ◽  
Vol 32 (1) ◽  
pp. 14-18 ◽  
Author(s):  
L. Ujejski ◽  
E. R. Waygood
Keyword(s):  
Sulphuric Acid ◽  
Colorimetric Determination ◽  
Pure Solution ◽  
Naturally Occurring ◽  
Cysteine Hydrochloride ◽  
Color Reactions

The reagents carbazole – sulphuric acid, cysteine hydrochloride – sulphuric acid, have been applied successfully to the quantitative colorimetric determination of sedoheptulosan in pure solution or in the presence of ribose and/or fructose. Fructose can be determined quantitatively in the presence of sedoheptulosan and/or ribose by using a combination of the two reagents. Results indicate that while sedoheptulose reacts differently to sedoheptulosan with the orcinol reagent, the reactions with carbazole and cysteine are not altered by hydration and these may form a basis for the determination of the naturally occurring seven carbon sugar sedoheptulose.

scholarly journals Rhodamine-Sulphuric Acid -A New Visualization Reagent for the Determination of Sucralose by HPTLC

2010 ◽  
Vol 7 (s1) ◽  
pp. S559-S565 ◽  
Author(s):  
Mohd Idris ◽  
Seema Srivastava ◽  
T. R. Baggi ◽  
S. K. Shulka ◽  
A. K. Ganjoo
Keyword(s):  
Sulphuric Acid ◽  
Limit Of Detection ◽  
Solvent System ◽  
Artificial Sweetener ◽  
Yellow Fluorescence ◽  
Relative Standard ◽  
Golden Yellow ◽  
Solvent Systems ◽  
Olive Green

Sucralose a UV-visible inactive compound was separated on silica gel plate without any plate treatment prior to analysis, derivatized with rhodamine - sulphuric acid reagent and detected densitometrically at 456 nm as olive green band. With this reagent sucralose also shows golden yellow fluorescence at 366 nm. Two new solvent systemsi.e. chloroform: methanol: toluene (v/v 5:3.5:1.5) (solvent system-I) and chloroform: ethanol: benzene (v/v 5:3:2) (solvent system-II) were developed and giving Rfvalues of 0.62 and 0.45 respectively. The method was found to be sensitive with good limit of detection (LOD) for two solvent systems. The method imparts specificity to the method as at 456 nm sucralose only gives olive green color spots where as other artificial sweeteners did not show any response to this reagent, where as carbohydrates gives black color spots. Similarly sucralose gives golden yellow fluorescence at 366 nm which is not given by any other artificial sweetener. The method was highly reproducible with relative standard deviation (RSD)≤3% (n=3) and was applied for the determination of sucralose in different matrices like cola drinks, lemon juices, sugar free sweets, tabletop sweeteners etc.etc.

Bioenergy II: Furfural Destruction Kinetics during Sulphuric Acid-Catalyzed Production from Biomass

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
Gianluca Marcotullio ◽  
Miguel A. Tavares Cardoso ◽  
Wiebren De Jong ◽  
Ad H.M. Verkooijen
Keyword(s):  
Sulphuric Acid ◽  
Acid Concentration ◽  
Reaction Products ◽  
Arrhenius Law ◽  
Exponential Factor ◽  
Oil Derivatives ◽  
Destruction Kinetics ◽  
Acid Catalyzed ◽  
Effects Of Temperature

The interest for furfural has increased in the last years due to its potential for competing with oil derivatives as platform chemical. In addition, furfural, derived from C5 sugars, can play a key role in the valorization of the hemicellulose contained in biomass when considering the development of a modern biorefinery concept. The development of such new and competitive biorefinery processes must be based on accurate kinetic data for the reactions involving furfural in the conditions used for its production.This work addresses the determination of furfural destruction kinetics in aqueous acidic environment, using sulphuric acid as catalyst, in the temperature range 150 - 200°C, acid concentration range 36.4 - 145.5 mM and furfural initial concentration between 60.4 and 72.5 mM. These studies were carried out using a recently built lab-scale titanium reactor that enables liquid phase reactions in a relatively broad range of conditions.The obtained results show that destruction of furfural follows first-order reaction kinetics within the range of temperature and acid concentration evaluated. Moreover, the proposed kinetic model takes into account the effects of temperature and acid dilution on the ions activity, and thus H3O+, by using the electrolyte Non-Random Two-Liquid (eNRTL) model. By using this approach, the rate constant dependence on temperature could be described by the Arrhenius law and thus the activation energy could be estimated as being 125.1 [kJ/mol] and the pre-exponential factor 3.71•1011[s-1]. Separation of different reaction products was achieved by means of HPLC, these products were not yet completely identified. Contrarily to what is reported in previous works, formic acid formation from furfural under the tested conditions can be regarded as playing a far less pronounced role than suggested before.

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