Bulk acidity

Hot potassium carbonate is generally considered for bulk acid gas removal applications. Often a secondary removal step using an alkanolamine is also used to meet product specifications. 

Boiler water treatment Base exchange Dealkylization Demineralization Demin, water tank Demin, water pump Bulk acid and alkali storage Neutralizing... 

Are raw process and waste materials stored in a safe and appropriate manner for example, are bulk acids in tanks bunded with secondary containment, are flammable materials in a fire-protected, ventilated store, are powders and pellets in areas fitted with dust extraction segregation of noncompatible materials Provide details of existing storage arrangements, inducing plans and specifications. Identify risk areas. Identify the risk category. 

Fig. 44. Relationships between catalytic activity and bulk acidity, (a) (O) Dehydration of 2-propanol, (A) decomposition of formic acid, ( ) conversion of methanol, (ta) ( ) Isomerization of cjs-2-butene after treatment at 423 K, ( ) isomerization of m-2-butene after treatment at 573 K. (From Ref. 46b.)...

The variations of surface and bulk acidic characters after coking... 

It was found by Nis XPS studies of pyridine-adsorbed samples that after deactivation the surface acidic function changes in a different manner with the bulk acidity measured by infrared characteristic absorption bands of pyridine adsorbed samples [7], which would suggest different distributions of the acidic properties in the sample catalysts. The effects of additive elements on the overall acidic features of modified zeolite catalysts are dependent on sample pretreatment and/or reaction condition, which will contribute differently to the induced acidity on the surface and in bulk bifunctional properties, as examined by the reaction of n-heptane shown in Figure 1. 

For acid catalysis, the rates of bulk-type reactions show close correlations with the bulk acidity, while the catalytic activities for surface-type reactions are related to the surface acidity which is sensitive to the surface composition and often change randomly. Similarly, in the case of oxidation catalysis, good correlations exist between the oxidizing ability of catalyst and the catalytic activity for oxidation in both bulk-type and surface-type reactions. Acid and redox bifunctionality is another characteristic of HPAs. For example, the acidity and oxidizing ability work cooperatively for the oxidation of mcthacrolcin, whereas they function competitively for the oxidative dehydrogenation of isobutyric acid [5]. Interestingly, the former is of surface type and the latter of bulk type. 

One of these is the question of where does the reaction occur It is often assumed that alkylation proceeds in the bulk acid phase (12a), but one of the aims of this report is to show that alkylation must proceed in at least two phases and that the reaction occurring at the hydrocarbon-acid interface is by far the most important in controlling the quality or selectivity of alkylate i.e. the formation of a Cg fraction from isobutane plus butenes while minimizing the production of side products. The fact that alkylation does not occur uniformly throughout the acid has been recently suggested by Doshi and Albright (12b). 

It was also found that the methylcyclopentane concentration in the acid phase was about 60 ppm. An order of magnitude calculation indicates that the diffusion of methylcyclopentane Into the bulk acid phase occurs much faster than the rate of formation of Isobutane. Thus the acid phase should be considered to be saturated with methylcyclopentane throughout the reaction In all the kinetic experiments. 

The fact that hydride transfer shows a dependence on the methylcyclopentane concentration in the emulsion Is consistent with a reaction occurring at the acid-hydrocarbon interface. It would be inconsistent with reaction occurring only in the bulk acid phase since there the methylcyclopentane concentration Is constant. 

The fact that some Increased rates are observed suggests that we have Increased cationic reactivity by weakening the acid and destabilizing carbonlum Ion Intermediates. The lack of correlation with solubility of the hydride donor again Indicates that significant hydride transfer does not occur In the bulk acid phase. Rather, the data are more easily understood If the reaction occurs primarily at the acid-hydrocarbon Interface under well mixed conditions. 

As the ion concentration in the acid grows toward a steady state value, alkylation and polymerization-cracking reactions occur which generate a distribution of C5" " to Cg" " ions in the acid. An estimate of this "homogeneous" alkylate distribution in the bulk acid can be made from the product distribution at the earliest times shown in Figures 8 to 11. 

The drop In the DMH/TMP ratio suggests that a second reaction site which preferentially yields trlmethylpentanes develops with time. This should be the Interfaclal reaction. A rough measure of the relative Importance of the second site can be made by assuming that bulk acid yields a DMH/TMP ratio of 0.33 and that the Interface yields pure TMP. In order to obtain a typical product with DMH/TMP = 0.15/1 the ratio of product formed at the Interface to that formed in the bulk acid Is about 1 1. 

Intermediates and causes them to abstract hydride Ions more rapidly from Isobutane or any other potential donor. Increased hydride transfer converts more of the carbonlum Ions at the add Interface to saturates faster, yielding product while minimizing polymerization and side reactions. It Is also likely that the surfactants physically block alkyl Ions from one another in the surface film and thus Impede Ion + olefin polymerization. In such a film the carbonlum Ion concentration must also be lower than In the absence of surfactant and mass law effects will therefore also lead to less polymerization and cracking. The fact that steady state hydride transfer rates In H2SO are subject to control through the use of acid modifiers which act In the bulk acid and at the acid-hydrocarbon Interface Is the key to the control of sulfuric acid alkylation. 

Within the pharmaceutical industry, these materials are utilized for bulk acid storage at room temperature, storage of dry powders, piping of potable water, sewer lines, and wastewater treatment. The Food and Drug Administration (FDA) recognizes acceptable materials for food contact in the Code of Federal Regulations (CFR) 21 part 177. 

Figure 6.23 Infrared spectra and a model of a HOOC—( 012)30—COO H monolayer on silver. A comparison with spectra of all-trans configured bulk acid (lower and dotted traces) clearly indicate the gauche bend in the monolayer (compare with Figure 5.16).

Nevertheless, there are limitations of even the most advanced amines-only based gas treatment technologies in handling very highly add gas loaded natural or associated oil field gases - especially for bulk acid gas removal when the acid gases are destined for cycling and/or disposal by re-injection. 

Finally, Total in collaboration with IFF has embarked upon a comprehensive program with a pooling of resources to develop new gas treatment technologies to better suit the bulk acid gas removal destined for re-injection applications. To this end, pre-treatment techniques and hybrid solvent processes are envisioned as the most cost-effective overall solutions. 

The upstream acid gas pre-extraction technique from IFF, called SFREX, offers a synergistic combination with the Elf Activated MDEA process in most applications for bulk H2S rich acid gas disposal projects. The substantial reduction of the acid gas removal and re-compression loads afforded by the SFREX step coupled with energy efficient flash procured Activated MDEA process achieves sour gas purification with bulk acid gas disposal very cost-effectively. 

Interesting supports are the polymeric materials, notwithstanding their thermal instability at high temperatures. In the electrocatalysis field, the use of polypyrrole, polythiophene and polyaniline as heteropolyanion supports was reported [2]. The catalytically active species were introduced, in this case, via electrochemical polymerization. Hasik et al. [3] studied the behavior of polyaniline supported tungstophosphoric acid in the isopropanol decomposition reaction. The authors established that a HPA molecular dispersion can be attained via a protonation reaction. The different behavior of the supported catalysts with respect to bulk acid, namely, predominantly redox activity versus acid-base activity, was attributed to that effect. 

Molybdophosphoric acid was also used to prepare HPA-polymer composite film catalysts, using polyphenylene oxide, polyethersulfone and polysulfone as polymers [4], The membrane-like materials were tested as catalysts in the liquid-phase synthesis of tert-butanol from isobutene and water, showing higher catalytic activity than the bulk acid. 

Fig. 3. FT-IR spectra of MS and MS-F supported TPA (MPA), and the bulk acids (a, b) and the catalysts after leaching with ethanol/water (c, d).

In Walker v. Stauffer Chemical Corporation, the defendant manufactured bulk sulfuric acid. After that product left the defendant it was compoimded into a product by a customer, packaged and subsequently sold, through distributors, to a manufacturer of drain cleaning compounds. The compounding process involved a change in the chemical composition of the bulk acid the acid was substantially altered not only as to its chemical composition but also as to the containers in which it was distributed. In this case the ultimate product was in no way considered to be the one in the same sulfuric acid which was distributed by Stauffer. The case arose as a result of injuries sustained from an explosion of the drain cleaner. The question before the court was whether Stauffer, the manufacturer of bulk sulphuric acid, was required to transmit warnings of the explosion potential of the cleaning compounds. The court in this case said ... 

As for the acidic properties (amount, strength and type of acid sites) of solid heteropoly compounds, bulk acidity as well as surface acidity must be considered, since acid catalysis often occurs in the solid bulk. These acidic properties are sensitive to the counter cations as well as to the constituent elements of polyanion. The acid forms are protonic acids and the acid strength reflects that in solution. In the case of salts, there are several possible mechanisms for the origins of the acidity. 

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