Acid continued concentration, dependence

In continuous treatment Nowcorr 800 is added to the drilling fluid or to the acid blends. The concentration depends on downhole conditions temperature, total pressure and... 

The rate of hydrolysis of carboxylic esters can be increased by raising the temperature. It is also advantageous to remove the alcohol produced by continuous distillation. Acid hydrolysis is dependent on the hydrogen ion concentration it is usually considerably slower than alkaline hydrolysis of esters. 

The concentration dependence of the Brookfield viscosity (Figures 9 and 10) indicates a rapid drop in viscosity upon dilution below a critical concentration. Bagley (7) attributed such rheological behavior to a structure of swollen, deformable gel particles closely packed in intimate contact. Davidson (8) later attributed the thickening efficiency of a cross-linked poly(acrylic acid) to the dispersed rather than the continuous phase. In general, pseudoplastic and viscoplastic rheology is characteristic of dispersions with low... 

Figure 6.10 Effect of streptokinase (SK) on fibrinogen concentration and platelet aggregation induced by ADP in platelet-rich plasma. Platelets were incubated with streptokinase for 1 minute prior to the addition of ADP, lfimo L and aggregation monitored by light transmission. Samples for fibrinogen were collected in aprotinin to prevent continued lysis. The fibrinogenolytic and proaggregatory effects of streptokinase were concentration dependent and were inhibited by aprotinin and e-aminocaproic acid (e-ACA)...

The treatment of 1 with an aqueous solution of NaOH yields a-ethyl-a-N-(hydroxyethylamino)methyl phosphonic acid 2 after treatment with Dowex 50WX8-200 [89]. a-Ethyl-N-(phosphonomethyl) glycine 3 is obtained by oxidation of 1 or 2 [90]. The cytotoxicity of the new aminophosphonic acids has been studied in continuous cell line and was expressed as a concentration-depending reduction of the uptake of the vital dye Neutral Red (ICjq) (Table 4.1) [91]. The results obtained showed that 4-ethyl-2-hydroxyl-2-oxo-1,4,2-dioxaphosphorinane and a-ethyl-a-(hydroxyethy-lamino)methyl phosphonic acid are toxic compounds. The sodium salt of the... 

Incorporation of additives (ovalbumin, progesterone) resulted in a decrease of tensile strength, modulus and elongation at break compared to fibres without additive. A continuous decrease in the properties was observed with increasing concentration of the additive. Similar concentration-dependent deterioration of mechanical properties was observed also if A -(3,4-dimethoxyciimamoyl)-anthranilic acid was mixed into PCL fibres during melt spiiming. ... 

While some autiiors assumed and observed in anl dnxis formic add a continuous increase in reduced specific viscoaty with d ieasing n cm ccmcentration (Fig. 5), others under the same conditions found a sharp maximum on the same depraidence in the range of very low concentrations. An imponounced maximum observed on the concentration dependence of i7gp/c in a solution of nylcm 6 in anhydrous sulphuric acid indicates an only incon lete suppression of the polyelectrolyte effect due to partial dissociation of the add itself The effect can be totally suppressed by a mere I wt-% of water. 

Hofmann and coworkers (327-330) have reported a series of studies on the deactivation kinetics for the heterogeneously catalyzed disproportionation of ethyl benzene to benzene and diethyl benzene under SCF conditions. Kinetic studies have been conducted in both a loop reactor using a protonated Y-faujasite (Z-14) catalyst (327) and in a continuous concentration-controlled recycle reactor using an HY-zeolite (HYZ) (329,330) and USY-zeolite, H-ZSM-5, and H-mordenite (328) under supercritical conditions T > 373 C, P > A5 bar). Coke extraction by SCFs was found to be strongly dependent on the type of catalyst used, and the Lewis acid centers were determined to play an important role in the coke formation and activity of the catalysts. A simple kinetic model for the catalyst deactivation was proposed (329) for SCF conditions and high ethyl benzene concentration. Based on the relatively high estimated deactivation energy of about 147 kJ/mol and first-order deactivation, the authors concluded that the catalyst deactivates much slower under SCF conditions than under atmospheric pressure. 

The continued effectiveness of the nitronium ion in relatively dilute solutions has been indicated by comparing the dependence of the rates on the concentration of sulphuric acid, with the acidity-dependence of the ionisation of model compounds. The (formerly or Cq) acidity... 

Aerosol Dynamics. Inclusion of a description of aerosol dynamics within air quaUty models is of primary importance because of the health effects associated with fine particles in the atmosphere, visibiUty deterioration, and the acid deposition problem. Aerosol dynamics differ markedly from gaseous pollutant dynamics in that particles come in a continuous distribution of sizes and can coagulate, evaporate, grow in size by condensation, be formed by nucleation, or be deposited by sedimentation. Furthermore, the species mass concentration alone does not fliUy characterize the aerosol. The particle size distribution, which changes as a function of time, and size-dependent composition determine the fate of particulate air pollutants and their... 

A simple, reliable, and fast method of determining the pH of a solution and of monitoring a titration is with a pH meter, which uses a special electrode to measure H 0+ concentration. An automatic titrator monitors the pH of the analyte solution continuously. It detects the stoichiometric point by responding to the characteristic rapid change in pH (Fig. 11.9). Another common technique is to use an indicator to detect the stoichiometric point. An acid-base indicator is a water-soluble organic dye with a color that depends on the pH. The sudden change in pH... 

Influence of the mode of operation on process performance. The mode of operation of stirred-tank reactors can also significantly affect reactor performance. The history of concentrations will be changed by the time policy of reactant(s) addition to the reaction mixture. In view of our very limited possibility of controlling of temperature in stirred-tank reactors, the temperature-time dependencies for different policies of dosing will also be different. For example, the result of nitration depends upon the method of addition of nitric acid to aromatics, and the choice which phase is dispersed and which is continuous. Consequently, if the reaction is concentration- or temperature-sensitive the result will be dependent on the mode of operation (see Example 5.3.1.5). 

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