Hydrolysis compared with

The electron-withdrawing power of the tnfluoromethyl group in the 2,2,2-tri-fluoroethyl ether of 9-hydroxy-9-(dinitromethyl)fluorene considerably retards its hydrolysis compared with simple alkyl ethers [59] (equation 57)... 

As discussed in section 2, the alkyltin component of organotin compounds is relatively stable to environmental degradation processes such as hydrolysis, compared with the association with the relative ligand (such as an isooctyl mercaptoacetate group). Thus, in water, most of the derivatives are reported to dissociate to the constituent alkyltin (usually as the chloride or the oxide) and the relevant anion (KemI, 2000). 

The present results suggest that the enzymatic hydrolysis process is at least competitive with the acid hydrolysis process. The main difficulty with it is the long time required for the hydrolysis, compared with the acid process. The present work suggested a mechanism for overcoming this problem, which is to remove the sugars as formed, perhaps by combining the enzymatic hydrolysis and the fermentation in one vessel at the same time. 

Cefaclor, cefuroxime axetil, cefprozil, and loracarbef can be given orally. The usual dosage for adults is 10-15 mg/kg/d in two to four divided doses children should be given 20-40 mg/kg/d up to a maximum of 1 g/d. Except for cefuroxime axetil, these drugs are not predictably active against penicillin-resistant pneumococci and should be used cautiously, if at all, to treat suspected or proved pneumococcal infections. Cefaclor is more susceptible to 13-lactamase hydrolysis compared with the other agents, and its usefulness is correspondingly diminished. 

Base (and water) hydrolysis of the 1 1 complex of the tetramethyl ester of EDTA with copper(II) ([Cu(Me4EDTA)]2+) has been investigated.82 In the complex probably two ester groups of the ligand are bonded to the metal ion in conjunction with the two nitrogen donors. Rate accelerations of the order of 10s were observed in base hydrolysis compared with the unprotonated ligand (Table 14). A variety of metal complexes of the ligand have also been isolated and characterized.83... 

For avoiding high losses in pentoses, another, more moderate hydrolysis method for lignin-containing material was developed. The method is proposed only if arabinose, xylose, galactose, and rhamnose are of interest. In this case, the material is swollen in 100% TFA and boiled with 20% TFA. The result of such a moderate hydrolysis, compared with that of an intensive hydrolysis, is demonstrated in Figure 7. It can be seen that after careful hydrolysis the areas of the peaks of rhamnose... 

Hydrolysis of inulin has already been performed in the presence of a zeolite, namely the zeolite LZ-M-8.[11] This catalyst has been found to be extremely selective towards hydrolysis compared with fructose decomposition, thus illustrating the superiority of the zeolite over sulfuric acid or ion-exchange resins as catalysts. As an example, a 96% yield in fmctose was obtained after 15 min at 130 °C starting from 2 ml of a 0.257 mol L 1 inulin solution and 0.25 g of zeolite. 

The rate of hydrolysis of egg albumin by pepsin exceeded that of soy proteins and decitraconylated yeast proteins (Figure 6). More than 90% egg albumin was hydrolyzed within 3 h of incubation whereas only 60% of the soy proteins and decitraconylated yeast proteins were hydrolyzed under the same conditions. Hydrolysis of egg albumin was not impaired by the presence of added citraconic acid (0.01M and 0.05M). So the hydrolysis of the citraconylated yeast proteins by pepsin was measured (see Figure 6). No differences occurred either in the rate or in the extent of hydrolysis compared with decitraconylated yeast proteins. More thorough nutritional studies and a safety evaluation of the citraconic acid must be conducted before either citraconylated or decitraconylated yeast proteins are used for human consumption. 

Boron trifluoride is one of the most avid acceptors—that is, strongest Lewis acids-—known, and readily unites with water, ethers, alcohols, amines, phosphines, etc., to form adducts. BF3 is commonly available as its diethyl etherate, (C2H5)26bf3. Because of its potency as a Lewis acid and its greater resistance to hydrolysis compared with BC13 and BBr3, BF3 is widely used to... 

PANIC at 250 MHz, has shown that it is the 1 3 2 6-triacetal and not the 1,2 3,5 A 6-trlacetal as previously claimed. The three products from acetalatlon of D-mannitol with 2-methoxypropene in DMF with tosic acid catalyst have been shown to be 1,2 5,6- 1 2 4 6- and 1,2 3,6-di-0-isopropylidene-D-mannitol. The preparation of 1 2 5,6-di-O-isopropylidene-D-mannitol by three alternative procedures for acetonation of D-mannitol has been investigated using acetylation and capillary g.l.c. to monitor the products. The highest yield was obtained by propanone-zinc chloride, whereas 2 2-dlmethoxypropane -tin(II) chloride and 2-methoxypropene - tosic acid gave more complex mixtures contrary to claims in the literature. A new trlacetal 1 2 3,6 4,5-trl-O-lsopropylidene-D-mannltol vas Isolated and its graded hydrolysis compared with that of 1 2 3 4 5 6-trlacetal. Acetal-... 

Segmented polyurethane elastomers, prepared from diisocyanates, macrodiols and chain extenders, are frequently used in the construction of implantable medical devices, such as cardiac pacemakers, heart valves, catheters, and heart assist devices, because of their excellent mechanical properties and haemocompatibility. Polyether macrodiols, such as poly(tetramethylene oxide) (PTMO), are used to prepare polyurethanes for implant, since they offer an increased resistance to enzymatic hydrolysis compared with polyester-based polyurethanes. 

Recent progress in food vitamin Bg analysis incorporates enzymatic hydrolysis of the phosphorylated vitamers prior to HPLC analysis (98). Vitamin Bg is subsequently measured by HPLC as the sum of PM, PN, and PL. The advantage of enzymatic hydrolysis compared with previously utilized acid hydrolysis is that Be vitamer glycosides are not hydrolyzed by phosphatases. 

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