Base hydrolysis, procedure

Griscom and coworkers [179,180] prepared 0-enriched and unenriched silica gels from TEOS using a two-step acid-base hydrolysis procedure with r = 3.8. After heating, the gels were sealed under vacuum and thereafter not subjected to atmospheric contamination during or after irradiation. 

Bermejo-Barrera P, I Ernanuez-Nocelo S, Moreda-PiSeiro A and Bekmejo-Barrera A (1999) Useftilness of enzymatic hydrolysis procedures based on the use of pronase E as sample pre-treatment for multi-element determination in biological materials. J Anal At Spcctrom 14 1893-1900. 

More recently, a colorimetric-based LAL procedure has been devised. This entails addition to the LAL reagent of a short peptide, susceptible to hydrolysis by the LAL clotting enzyme. This synthetic peptide contains a chromogenic tag (usually para-nitroaniline, pNA) which is released free into solution by the clotting enzyme. This allows spectrophotometric analysis of the test sample, facilitating more accurate end-point determination. 

The first objective has been accomplished by the development of an HPLC procedure as reported by Spalik et al. ( 5) and GC/NPD procedures developed by Lemley and Zhong ( ). The second and third objectives are being accomplished by fundamental solution studies and reactive ion exchange experiments conducted in parallel. Lemley and Zhong (7) determined recently the solution kinetics data for base hydrolysis of aldicarb and its oxidative metabolites at ppm concentrations and for acid hydrolysis of aldicarb sulfone. They have since ( ) reported similar results for ppb solutions of aldicarb and its metabolites. In addition, the effect on base hydrolysis of temperature and chlorination was studied and the effect of using actual well water as compared to distilled water was determined. Similar base hydrolysis data for carbofuran, methomyl and oxamyl will be presented in this work. 

The amide bonds in peptides and proteins can be hydrolyzed in strong acid or base Treatment of a peptide or protein under either of these conditions yields a mixture of the constituent amino acids. Neither acid- nor base-catalyzed hydrolysis of a protein leads to ideal results because both tend to destroy some constituent ammo acids. Acid-catalyzed hydrolysis destroys tryptophan and cysteine, causes some loss of serine and threonine, and converts asparagine and glutamine to aspartic acid and glutamic acid, respectively. Base-catalyzed hydrolysis leads to destruction of serine, threonine, cysteine, and cystine and also results in racemization of the free amino acids. Because acid-catalyzed hydrolysis is less destructive, it is often the method of choice. The hydrolysis procedure consists of dissolving the protein sample in aqueous acid, usually 6 M HC1, and heating the solution in a sealed, evacuated vial at 100°C for 12 to 24 hours. 

The hydrolysis procedure is based on heterogeneous carbonyl-selective fluorescence labeling with CCOA, which is subsequently released with triflic... 

Ligands 56 and 46 were made by the same procedure except that in 56 iV-(2-chloroethanoyl)-2-phenylethylamine was replaced by a combination of paraformaldehyde and MeP(OEt)2 and the resulting triphosphi-nate ester was subjected to base hydrolysis. 

Hydrolysis by Emmons path 2 has been suggested" as a method for converting amines to ketones, the acid counterpart of a base-catalyzed procedure cited previously. The oxaziridines were obtained by oxidation of the product from amines and acetone, and hydrolyzed with 2M hydrochloric acid at room temperature for 40 hours. The only aliphatic aldehyde produced was not stable under these conditions. This reaction has received further study. ... 

CoDolvmer Characterization. The base-catalyzed hydrolysis reaction of polyacrylamide has been studied by several workers (27-29). Halverson, et al. (29) concluded from Interpretations of C NHR spectra that a well-spaced distribution of acrylate groups Is produced along the polymer chain. This hydrolysis procedure offered an opportunity to prepare nearly model copolymers free of chemical sequence heterogeneity. 

Complexes of trifluoromethanesulfonate anion with cobalt(III) are labile oward substitution under mild conditions, and they have proved to be useful synthetic precursors to a variety of aminecobalt(III) complexes. The pentaammine-(trifluoromethanesulfonato-O)rhodium(III) ion, which is readily prepared from [Rh(NH3)5Cl]Cl2 in hot CF3SO3H, is also versatile as a synthetic precursor. " Its synthesis and solvolysis to give essentially quantitative yields of the penta-ammineaqua- and hexaamminerhodium(III) ions are described below. The aqua complex has previously been prepared by the base hydrolysis or Ag -induced aquation of [Rh(NH3)5Cl]Cl2 in water, but the present method presents a cleaner and more rapid alternative. The methods for preparation of the [RhCNHj) ] ion have evolved from the procedure of J0rgensen. They involve prolonged reaction of [Rh(NH3)5Cl]Cl2 with ammonia in a pressure vessel at elevated temperature. The solvolysis of [Rh(NH3)5(0S02CF3)](CF3S0j)2 in liquid ammonia is a simple, high-yield, and rapid alternative. 

Various procedures to convert the sulfated esters to diol esters have been reported (Quilliam et al., 1996) however a base hydrolysis for the determination of total OA group toxins in samples is recommended (McNabb et al., 2005). 

The synthesis of the twistane-ketal 279 using endo-6-hydroxy-9-oxabicyclo[3.3.1]-nonan-2-one (274) or its acetate 227, resp., was nevertheless successful by applying the following route according to a procedure by Inhoffen etal. the keto-acetate 221 was treated with trimethyl orthoformate. From the reaction mixture which contained the dimethoxy-ketals 222 and 223 as well as the enolethers 224 and 225, the acetates 222 (63%) and 224 (5%) were isolated by chromatography. On base-hydrolysis they gave the alcohols 223 and 225. Pyrolysis of the ketal 222 and simultaneous distillation yielded 67% of the enolether 224. Finally by treating the dime-... 

Q2 (Rl) Validation of Analytical Procedures Methodology Page 7 [specificity] As appropriate, this should include samples stored under relevant stress conditions, light, heat, humidity, acid/base hydrolysis and oxidation... 

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