Particles aldehyde-containing

Another route to the formation of a hydrazide on a surface is to use an aldehyde-containing particle (such as HEMA/acrolein copolymers) and subsequently modify the aldehydes to form hydrazone linkages with bis-hydrazide compounds, which then can be stabilized by reduction with sodium cyanoborohydride (Chapter 2, Section 5). The resulting derivative contains terminal hydrazides for immobilization of carbonyl ligands (see Figure 14.18). 

Figure 14.18 Carboxylate-particles or aldehyde-particles can be modified with the carbohydrazide in excess to create a hydrazide-particle that can be used to couple with aldehyde-containing molecules.

Figure 14.19 Aldehyde-containing molecules, such as periodate-oxidized carbohydrates or glycoproteins, can be coupled to hydrazide-particles to form a hydrazone bond. This bond can be further stabilized by reduction...

Controlling fluid loss loss is particularly important in the case of the expensive high density brine completion fluids. While copolymers and terpolymers of vinyl monomers such as sodium poly(2-acrylamido-2-methylpropanesulfonate-co-N,N-dimethylacrylamide-coacrylic acid) has been used (H)), hydroxyethyl cellulose is the most commonly used fluid loss additive (11). It is difficult to get most polymers to hydrate in these brines (which may contain less than 50% wt. water). The treatment of HEC particle surfaces with aldehydes such as glyoxal can delay hydration until the HEC particles are well dispersed (12). Slurries in low viscosity oils (13) and alcohols have been used to disperse HEC particles prior to their addition to high density brines. This and the use of hot brines has been found to aid HEC dissolution. Wetting agents such as sulfosuccinate diesters have been found to result in increased permeability in cores invaded by high density brines (14). 

Figure 14.21 Aldehyde-particles can be reacted with amine-containing proteins or other molecules to form intermediate Schiff bases, which can be stabilized by reduction with sodium cyanoborohydride.

Aldehyde particles are spontaneously reactive with hydrazine or hydrazide derivatives, forming hydrazone linkages upon Schiff base formation. Reactions with amine-containing molecules, such as proteins, can be done through a reductive amination process using sodium cyanoborohydride (Figure 14.21). 

Wash 10 mg of aldehyde particles 3 times with 10 mM sodium phosphate, pH 7.4 (coupling buffer). Buffers of higher pH value (i.e., carbonate buffer at pH 10) will result in more efficient Schiff base formation with amine-containing molecules than neutral pH conditions. 

Electrically conducting polymer particles such as polypyrrole and polyaniline could also be prepared by dispersion polymerization in aqueous ethanol (31). The oxidation polymerization of pyrrole and aniline has been carried out at the electrode surfaces so far and formed a thin film of conducting polymer. On the other hand, polypyrrole precipitates as particles when an oxidizing reagent is added to a pyrrole dissolved ethanol solution, which contains a water-soluble stabilizer. In this way electrically conducting polymer particles are obtained and, in order to add more function to them, incorporation of functional groups, such as aldehyde to the surface, and silicone treatment were invented (32). 

The furan aldehydes HMF and furfural were determined by HPLC using a Waters 2690 separation module, with a binary pump, an autoinjector, and a diode array detector at 282 nm. The furan aldehydes were separated on a YMC ODS-AL column (50 x 3 mm, 120 A, and 5-pm particles) (Waters, Milford, MA). The flow rate was 0.8 mL/min. Elution was performed with a gradient composed of Milli-Q water and acetonitrile containing 0.016% (v/v) trifluoroacetic acid. The gradient was formed in four steps over 17 min. In the first step, 10% acetonitrile was added for 3 min. 

In a 2-1. two-neck ilask fitted with a short reflux condenser and mechanical stirrer (Note 1) are placed 400 cc. of dry xylene (Note 2) and 29 g. (1.26 moles) of clean sodium (Note 3) cut in small pieces. The flask is surrounded by an oil-bath and heated until the sodium has melted. At this point the stirrer is started and the sodium is broken up into very small particles (Note 4). The oil-bath is removed but stirring is continued until the sodium has solidified as very fine particles. The xylene is then poured off, and to the sodium is added 455 cc. (4.7 moles) of absolute ethyl acetate (Note 5) containing 3-4 cc. of absolute ethyl alcohol (Note 6). The flask is quickly cooled to o° and 106 g. (1 mole) of pure benzaldehyde (Note 7) is added slowly from a separatory funnel while the mixture is stirred. The temperature is held between o° and 50 (Note 8). The reaction starts as soon as the benzaldehyde is added, as is shown by the production of a reddish substance on the particles of the sodium. About one and a half to two horns are required for this addition. The stirring is continued until practically all of the sodium has reacted (one hour after all the aldehyde has been added). When most of the sodium (Note 9) has disappeared, 90-95 cc. of glacial acetic acid is added and the mixture is carefully diluted with... 

Highly hydrophobic sorbents including porous carbon and copolymers of styrene and divinylbenzene (SDB) were widely investigated for environmental applications. The particle-loaded membranes containing modified SDB particles with surface sulfonic acid groups were successfully used for recovering different alcohols, phenols, aldehydes, ketones, or esters from aqueous samples [221]. Carbon-based PLM were also used for isolation of highly polar pesticides from water [222]. 

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