Solubilization strong acids

Homogeneous catalysts have been reported, which can oxidize methane to other functionalized products via C-H activation, involving an electrophilic substitution process. The conversion of methane into methyl bisulfate, using a platinum catalyst, in sulfuric acid, has been described. The researchers found that a bipyrimidine-based ligand could both stabilize and solubilize the cationic platinum species under the strong acidic conditions and TONs of >500 were observed (Equation (5)).13... 

Hi) Use of pH indicators and buffers. The most common method is to inject into reverse micelles various organic dyes (indicators) whose absorption spectra depend on pH, and observe the shift of those spectra with respect to the injected water solution. Dye solubilization shows that the micellar cores in hydrocarbon solutions can be either strongly acidic or basic. The determination of the pKa of an indicator in the presence of detergent aggregates in non-aqueous solvents is intrinsically more complex than in aqueous system. 

Micellar solutions of detergents such a sulfonates, phenolates and salicylates enhance the solubilizing properties of succinimide additives. For small concentrations of about 0.25% w/w sulfonate and 2.8% succinimide, a synergistic effect is observed, but for high sulfonate concentrations, the quantity of acid solubilized is less than that observed for succinimide alone (Bradley and Jaycock, 1972). A different mechanism exists for the solubilization of those weak acids and for strong acids. The different interaction between the amine groups in the polar head of a succinimide micelle and a weak acid (WH), and for a strong acid (SH), indicates that the weak acid is much better solubilized as ... 

A second collagen sample was bovine Achilles tendon collagen (Schwartz Mann, Inc.). This material resisted solvation in all simple aqueous solutions and even in strong acids, but it could be solubilized with time by dichloroacetic acid (DCA). Thus, films formed from this sample had to be cast from DCA. 

Absorption or adsorption of proteins. Reduce nonspecific interactions by changing HPLC mode add protein-solubilizing agent, strong acid or base (with polymeric columns only), or detergent such as SDS to mobile phase. 

The ionic-potential (Ip) concept discussed in Chap. 3 best describes element behavior at intermediate pH s. Most of the metal oxides and hydroxide minerals formed by cations with Ip values between about 3 and 8.2 become significantly soluble in acid waters, where the high H+ concentrations can break metal-0 or metal-OH bonds to form water and release metal cations to solution. Some of these otherwise insoluble metal oxides and hydroxides (for example, those of Al and Fe " ) are also solubilized by high pH s. In other words, the mobilities of these metal cations depend on the acid-base properties of the water, as well as on their ionic potentials. The rate of chemical weathering is also greatly accelerated in strongly acid waters. 

Solubilized vat dyes behave towards wool very much as if they were acid dyes. Thus the rate of exhaustion is increased by the addition of acid to the dyebath and they are fixed to the protein fibre by chemical bonds. They are, however, much more difficult to oxidize on protein than on cellulosic fibres. Soluble Vat Blues O and OR are dyed in fairly strongly acid liquors containing 2 to 4 per cent of formic acid, one per cent of sulphoxylate and 5 per cent of sodium sulphate. Most of the other soluble... 

Polyaniline (PAn) is most amenable to solution processing. The emeraldine base (EB) form of PAn is soluble in selected solvents such as methyl pyrrolidinone1 or strong acids.2 3 More recently, it has been discovered that solubility of the doped form can be induced by the use of appropriate surfactant-like molecules as dopants.4 Camphorsulfonic acid (HCSA) and dodecylbenzenesulfonic acid have proved particularly useful in this regard. Once solubilized, these PAn s can be cast into sheets or blended with other conventional polymer structures. For example, the pres-... 

The same structural characteristics that are responsible for the excellent thermal properties of these materials are responsible for their limited solubility as well as good chemical resistance. PPTA is soluble only in strong acids like H2SO4, HF, and methanesulfonic acid. Preparation of this polymer via solution polymerization in amide solvents is accompanied by polymer precipitation. As expected, based on its structure, MPDI is easier to solubilize then PPTA. It is soluble in neat amide solvents like A-methyl-2-pyrrolidone (NMP) and dimethylacetamide (DMAc), but adding salts like CaCl2 or LiCl significantly enhances its solubility. 

In so far as microdomains in water are concerned, partially quaternized polytertiary amines with pendant tertiary amine groups possess a property of special interest. The deprotonated microdomains can be readily destabilized by adding strong acids, which cause protonation of tertiary amine residues and thus solubilize the polymer chains conventionally. The destabilization occurs at a constant pH through cooperative chemical and conformational transitions of the all-or-none type for a large range of the degree of protonation.2... 

The destabilization is absolutely reversible and the microdomains reform immediately by adding bases which cause deprotonation of the formerly protonated tertiary amine residues. Such behavior is of special interest if temporary trapping of hydrophobic water-insoluble species by solubilization in the microdomains is desired. Indeed, the trapped species should be releasable instantaneously and at constant pH by adding at most a stoichiometric amount of strong acid. 

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