Solubilization requirements

The dehalogenase activity of dehydrated cells of R. erythropolis, for both chlorinated and brominated compounds, increases with the carbon chain length of the compound (up to 1-chlorohexane and 1-bromohexane). The opposite has been reported for the aqueous phase for both the isolated enzyme [54] and resting cells [14]. Eliminating solubilization requirements also clearly improves rates of... 

The simplest, and at the same time the most effective way to achieve dispersion in water or aqueous media is the addition of amphiphihc molecules carbon nanotubes without any functional groups are hydrophobic. This characteristic may be employed to enclose them in micelles. The surfactant molecules arrange around the single tubes with their hydrophilic head directed outward and their hydrophobic tail oriented toward the nanotube in the center. In this manner, each individual tube is surrounded by an envelop that enables a dispersion, for example, in water. Yet complete solubilization requires considerable amounts of the surfactant. Solutions obtained this way may in fact contain up to 80% of detergent and only 20% of carbon nanotubes. Surfactants suitable to enclose nanotubes in micelles include, for example, sodium dodecylsulfate (SDS), Triton X-100, or octadecyl-trimethylammonium bromide (OTAB). 

Homogeneous solubilization requires that the nucleophilic solid have some finite solubility (though low) in the organic phase and involves the dissolution of the inorganic salt in the organic phase, followed by ion exchange of the quat in the liquid phase with dissolved MY. The PT catalyst does not... 

It appears that the presence of monovalent salt during cooking enhanced both pectin solubilization and Ca" displacement into the liquor, and that the use of the same concentration of salt after cooking in distilled water displaced Ca " but did not increase the liquor pectin concentration. Salt-enhanced pectin solubilization required cooking, but enhanced Ca " displacement took place apart from cooking. Both consequences of the presence of salts were associated with decreased canned bean firmness. 

The results discussed in the course of this article on the synthesis of new, structurally defined PPP derivatives demonstrated the qualitative leap from a purely structurally motivated search for new conjugated macromolecules to the synthesis of structurally defined, processable PPP materials with properties tailor-made for a particular application. Precisely the combination of the solubilization required for processability and... 

Studying the impact of acyl tails showed that PC dismption was quite general, as lipid vesicles containing distearoyl (DS), dipalmitoyl (DP), dimyristoyl (DM), dilauroyl (DL), and dio-leoyl (DO) acyl tails all dismpted easily at reduced pH and above This solubilization requires high polymer-lipid ratios, for example, 50 wt.% for PEAA and DPPC. DOPC takes hours, while DPPC rearranges in minutes. The rate of micelli-zation for PC vesicles by PEAA was characterized by the reciprocal of the time to reduce the optical density by half, 1/Ti/2 Comparing DMPC to DPPC MLVs at pH 6.5, it was determined that the rate is faster for DMPC than DPPC and that both rates are inaeased above T. The increased rates near the... 

According to the Winsor premise, an augmentation in solubilization requires an increase in both the numerator (lipophilic interactions Aco—Aoo> etc.) and the denominator (hydrophilic interactions Acw etc). According to Table 1, it is possible to shift several formulation variables to increase or decrease the numerator and denominator, and in particular to make one of the double formulation changes as illustrated in Fig. 23. The first change departs from one optimum formulation, whereas the second change returns to another. 

Firefly luciferase from P. pyralis is a 50-kDa single polypeptide (550 amino acids). A C-terminal tripeptide sequence, —Ser—Lys—Leu, serves as the peroxisomal translocation signal, and its removal abolishes import of the enzyme into peroxisomes. Luc is hardly soluble in water, and its solubilization requires some salt. In solvents of relatively low ionic strengths, the protein aggregates in a rapidly reversible manner as the solubility limit is approached (69). 

Starting from fresh tissues, or tissues dehydrated with acetone, a limited amount of the mucopolysaccharide can be extracted with water or with salt solution. However, a large proportion seems to be bound to protein, and solubilization requires degradation of the protein part with enz mnes, or scission of the carbohydrate-protein linkage with weak alkali. 

The cleaning process proceeds by one of three primary mechanisms solubilization, emulsification, and roll-up [229]. In solubilization the oily phase partitions into surfactant micelles that desorb from the solid surface and diffuse into the bulk. As mentioned above, there is a body of theoretical work on solubilization [146, 147] and numerous experimental studies by a variety of spectroscopic techniques [143-145,230]. Emulsification involves the formation and removal of an emulsion at the oil-water interface the removal step may involve hydrodynamic as well as surface chemical forces. Emulsion formation is covered in Chapter XIV. In roll-up the surfactant reduces the contact angle of the liquid soil or the surface free energy of a solid particle aiding its detachment and subsequent removal by hydrodynamic forces. Adam and Stevenson s beautiful photographs illustrate roll-up of lanoline on wood fibers [231]. In order to achieve roll-up, one requires the surface free energies for soil detachment illustrated in Fig. XIII-14 to obey... 

In the first method a secondary acetylenic bromide is warmed in THF with an equivalent amount of copper(I) cyanide. We found that a small amount of anhydrous lithium bromide is necessary to effect solubilization of the copper cyanide. Primary acetylenic bromides, RCECCH Br, under these conditions afford mainly the acetylenic nitriles, RCsCCHjCsN (see Chapter VIII). The aqueous procedure for the allenic nitriles is more attractive, in our opinion, because only a catalytic amount of copper cyanide is required the reaction of the acetylenic bromide with the KClV.CuCN complex is faster than the reaction with KCN. Excellent yields of allenic nitriles can be obtained if the potassium cyanide is added at a moderate rate during the reaction. Excess of KCN has to be avoided, as it causes resinifi-cation of the allenic nitrile. In the case of propargyl bromide 1,1-substitution may also occur, but the propargyl cyanide immediately isomerizes under the influence of the potassium cyanide. 

There are numerous variations of the wet process, but all involve an initial step in which the ore is solubilized in sulfuric acid, or, in a few special instances, in some other acid. Because of this requirement for sulfuric acid, it is obvious that sulfur is a raw material of considerable importance to the fertilizer industry. The acid—rock reaction results in formation of phosphoric acid and the precipitation of calcium sulfate. The second principal step in the wet processes is filtration to separate the phosphoric acid from the precipitated calcium sulfate. Wet-process phosphoric acid (WPA) is much less pure than electric furnace acid, but for most fertilizer production the impurities, such as iron, aluminum, and magnesium, are not objectionable and actually contribute to improved physical condition of the finished fertilizer (35). Impurities also furnish some micronutrient fertilizer elements. 

Polyvinylpyrrohdinone/vinyl acetate copolymer (PVP/VA) was developed as an improved, less hygroscopic version of PVP. The monomer ratios control the stiffness and the resistance to humidity however, too high a vinyl acetate monomer content requires another solvent in addition to water to completely solubilize it. 

Solvents. The most widely used solvent is deionized water primarily because it is cheap and readily available. Other solvents include ethanol, propjdene glycol or butylene glycol, sorbitol, and ethoxylated nonionic surfactants. There is a trend in styling products toward alcohol-free formulas. This may have consumer appeal, but limits the formulator to using water-soluble polymers, and requires additional solvents to solubilize the fragrance and higher levels of preservatives. 

For deliming, ammonium salts and acids are used. The proportion of ammonium salts to acids and the type of acids employed is a matter of the tanner s choice. The acid neutralizes the lime, Ca(OH)2, thereby adjusting the pH. The ammonium salts have two functions to buffer the solution to a pH required for bating, and to form calcium ammonium complexes. The acidity and the complex formation solubilize the calcium and serve to bring the hide to the desired pH. 

For aqueous inks, the resins are water- or alkali-soluble or dispersible and the solvent is mosdy water containing sufficient alcohol (as much as 25%) to help solubilize the resin. To keep the alkah-soluble resin in solution, pH must be maintained at the correct level. Advances include the development of uv inks. These are high viscosity inks that require no drying but are photocurable by uv radiation. In these formulations, the solvent is replaced by monomers and photoinitiators that can be cross-linked by exposure to uv radiation. The advantage of this system is the complete elimination of volatile organic compounds (VOC) as components of the system and better halftone print quaUty. Aqueous and uv inks are becoming more popular as environmental pressure to reduce VOC increases. 

Enzyme—Heat—Enzyme Process. The enzyme—heat—enzyme (EHE) process was the first industrial enzymatic Hquefaction procedure developed and utilizes a B. subtilis, also referred to as B. amjloliquefaciens, a-amylase for hydrolysis. The enzyme can be used at temperatures up to about 90°C before a significant loss in activity occurs. After an initial hydrolysis step a high temperature heat treatment step is needed to solubilize residual starch present as a fatty acid/amylose complex. The heat treatment inactivates the a-amylase, thus a second addition of enzyme is required to complete the reaction. 

Production and Economic Aspects. Thallium is obtained commercially as a by-product in the roasting of zinc, copper, and lead ores. The thallium is collected in the flue dust in the form of oxide or sulfate with other by-product metals, eg, cadmium, indium, germanium, selenium, and tellurium. The thallium content of the flue dust is low and further enrichment steps are required. If the thallium compounds present are soluble, ie, as oxides or sulfates, direct leaching with water or dilute acid separates them from the other insoluble metals. Otherwise, the thallium compound is solubilized with oxidizing roasts, by sulfatization, or by treatment with alkaU. The thallium precipitates from these solutions as thaUium(I) chloride [7791 -12-0]. Electrolysis of the thaUium(I) sulfate [7446-18-6] solution affords thallium metal in high purity (5,6). The sulfate solution must be acidified with sulfuric acid to avoid cathodic separation of zinc and anodic deposition of thaUium(III) oxide [1314-32-5]. The metal deposited on the cathode is removed, kneaded into lumps, and dried. It is then compressed into blocks, melted under hydrogen, and cast into sticks. 

Most flavors that are designed for beverage alcohol products use ethanol as the primary solvent for the flavor. Glycerol [56-81-5] propylene glycol [57-55-6] and water are other common solvents in Hquid flavors. Some beverage alcohol concepts require the addition of an emulsified flavor, either as a vehicle to solubilize the oils in the beverage or as a deflberate attempt to cloud the product. This can best be accompHshed at lower proofs with the alcohol breaking the emulsion. 

Microemulsions or solubilized or transparent systems are very important ia the marketing of cosmetic products to enhance consumer appeal (32,41). As a rule, large quantities of hydrophilic surfactants are required to effect solubilization. Alternatively, a combination of a solvent and a surfactant can provide a practical solution. In modem clear mouthwash preparations, for example, the flavoring oils are solubilized in part by the solvent (alcohol) and in part by the surfactants. The nature of solubilized systems is not clear. Under normal circumstances, microemulsions are stable and form spontaneously. Formation of a microemulsion requires Httle or no agitation. Microemulsions may become cloudy on beating or cooling, but clarity at intermediate temperatures is restored automatically. 

The principal mbbers, eg, natural, SBR, or polybutadiene, being unsaturated hydrocarbons, are subjected to sulfur vulcanization, and this process requires certain ingredients in the mbber compound, besides the sulfur, eg, accelerator, zinc oxide, and stearic acid. Accelerators are catalysts that accelerate the cross-linking reaction so that reaction time drops from many hours to perhaps 20—30 min at about 130°C. There are a large number of such accelerators, mainly organic compounds, but the most popular are of the thiol or disulfide type. Zinc oxide is required to activate the accelerator by forming zinc salts. Stearic acid, or another fatty acid, helps to solubilize the zinc compounds. 

Dehydrobromination of 12 to -tetronic acid (13) in high yield could be achieved only under narrowly circumscribed conditions 62). The molar ratio of barium hydroxide to 12 needed to solubilize 12 and to neutralize the liberated hydrobromicacid must be at least two to one. Deionized water was the preferred solvent because of ease of workup. The yields were found to be concentration dependent. Concentrations of 12 in water of about 16% gave good yields of 13, whereas at 33% concentration the yield was much lower. One gram of 10% Pd-on-C per 33 g of 12 was required less catalyst gave incomplete reductions. 

Transition metal catalysis in liquid/liquid biphasic systems principally requires sufficient solubility and immobilization of the catalysts in the IL phase relative to the extraction phase. Solubilization of metal ions in ILs can be separated into processes, involving the dissolution of simple metal salts (often through coordination with anions from the ionic liquid) and the dissolution of metal coordination complexes, in which the metal coordination sphere remains intact. 

The two basic requirements for efficient bromine storage in zinc-bromine batteries, which need to be met in order to ensure low self-discharge and more over a substantial reduction of equilibrium vapor pressure of Br2 of the polybromide phase in association with low solubillity of active bromine in the aqueous phase. As mentioned by Schnittke [4] the use of aromatic /V-substitucnts for battery applications is highly problematic due to their tendency to undergo bromination. Based on Bajpai s... 

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